Physics of grain boundaries in polycrystalline photovoltaic semiconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Yanfa, E-mail: yanfa.yan@utoledo.edu; Yin, Wan-Jian; Wu, Yelong

2015-03-21

Thin-film solar cells based on polycrystalline Cu(In,Ga)Se{sub 2} (CIGS) and CdTe photovoltaic semiconductors have reached remarkable laboratory efficiencies. It is surprising that these thin-film polycrystalline solar cells can reach such high efficiencies despite containing a high density of grain boundaries (GBs), which would seem likely to be nonradiative recombination centers for photo-generated carriers. In this paper, we review our atomistic theoretical understanding of the physics of grain boundaries in CIGS and CdTe absorbers. We show that intrinsic GBs with dislocation cores exhibit deep gap states in both CIGS and CdTe. However, in each solar cell device, the GBs can bemore » chemically modified to improve their photovoltaic properties. In CIGS cells, GBs are found to be Cu-rich and contain O impurities. Density-functional theory calculations reveal that such chemical changes within GBs can remove most of the unwanted gap states. In CdTe cells, GBs are found to contain a high concentration of Cl atoms. Cl atoms donate electrons, creating n-type GBs between p-type CdTe grains, forming local p-n-p junctions along GBs. This leads to enhanced current collections. Therefore, chemical modification of GBs allows for high efficiency polycrystalline CIGS and CdTe thin-film solar cells.« less

Physics of grain boundaries in polycrystalline photovoltaic semiconductors

DOE PAGES

Yan, Yanfa; Yin, Wan-Jian; Wu, Yelong; ...

2015-03-16

Thin-film solar cells based on polycrystalline Cu(In,Ga)Se 2 (CIGS) and CdTe photovoltaic semiconductors have reached remarkable laboratory efficiencies. It is surprising that these thin-film polycrystalline solar cells can reach such high efficiencies despite containing a high density of grain boundaries (GBs), which would seem likely to be nonradiative recombination centers for photo-generated carriers. In this study, we review our atomistic theoretical understanding of the physics of grain boundaries in CIGS and CdTe absorbers. We show that intrinsic GBs with dislocation cores exhibit deep gap states in both CIGS and CdTe. Although, in each solar cell device, the GBs can bemore » chemically modified to improve their photovoltaic properties. In CIGS cells, GBs are found to be Cu-rich and contain O impurities. Density-functional theory calculations reveal that such chemical changes within GBs can remove most of the unwanted gap states. In CdTe cells, GBs are found to contain a high concentration of Cl atoms. Cl atoms donate electrons, creating n-type GBs between p-type CdTe grains, forming local p-n-p junctions along GBs. This leads to enhanced current collections. In conclusion, chemical modification of GBs allows for high efficiency polycrystalline CIGS and CdTe thin-film solar cells.« less

An over 18%-efficiency completely buffer-free Cu(In,Ga)Se2 solar cell

NASA Astrophysics Data System (ADS)

Ishizuka, Shogo; Nishinaga, Jiro; Koida, Takashi; Shibata, Hajime

2018-07-01

In this letter, an independently certified photovoltaic efficiency of 18.4% demonstrated from a completely buffer-layer-free Cu(In,Ga)Se2 (CIGS) solar cell is reported. A Si-doped CIGS thin film was used as the photoabsorber layer and a conductive B-doped ZnO (BZO) front electrode layer was directly deposited on the CIGS layer. Metastable acceptor activation by heat-light soaking treatment was performed to maximize the efficiency. The results presented here are expected to serve as a benchmark for simplified-structure CIGS devices as well as a reference for discussions on the role of buffer layers used in conventional CIGS solar cells.

Optical Physics of Cu(In,Ga)Se2 Solar Cells and Their Layer Components

NASA Astrophysics Data System (ADS)

Ibdah, Abedl-Rahman

Polycrystalline Cu(In1-xGax)Se 2 (CIGS) thin film technology has emerged as a promising candidate for low cost and high performance solar modules. The efficiency of CIGS solar cells is strongly influenced by several key factors. Among these factors include Ga composition and its profile in the absorber layer, copper content in this layer, and the solar cell multilayer structure. As a result, tools for the characterization of thin film CIGS solar cells and their layer components are becoming increasingly essential in research and manufacturing. Spectroscopic ellipsometry is a non-invasive technique that can serve as an accurate probe of component layer optical properties and multilayer structures, and can be applied as a diagnostic tool for real-time, in-line, and off-line monitoring and analysis in small area solar cell fabrication as well as in large area photovoltaics manufacturing. Implementation of spectroscopic ellipsometry provides unique insights into the properties of complete solar cell multilayer structures and their layer components. These insights can improve our understanding of solar cell structures, overcome challenges associated with solar cell fabrication, and assist in process monitoring and control on a production line. In this dissertation research, Cu(In,Ga)Se2 films with different Cu contents have been prepared by the one stage co-evaporation process. These films have been studied by real time spectroscopic ellipsometry (RTSE) during deposition, and by in-situ SE at the deposition temperature as well as at room temperature to extract the dielectric functions (epsilon1, epsilon 2) of the thin film materials. Analytical expressions for the room temperature dielectric functions were developed, and the free parameters that describe these analytical functions were in turn expressed as functions of the Cu content. As a result of this parameterization, the dielectric function spectra (epsilon 1, epsilon2) can be predicted for any desired composition within the range of the samples investigated. This capability was applied for mapping the structural and compositional variations of CIGS thin films deposited over a 10 cm x 10 cm substrate area. In another application presented in this dissertation, a non-invasive method utilizing ex-situ spectroscopic ellipsometry analysis has been developed and applied to determine non-destructively the Ga compositional profile in CIGS absorbers. The method employs parameterized dielectric function spectra (epsilon1, epsilon2) of CIGS versus Ga content to probe the compositional variation with depth into the absorber. In addition, a methodology for prediction of the external quantum efficiency (QE) including optical gains and losses for a CIGS solar cell has been developed. The methodology utilizes ex-situ spectroscopic ellipsometry analysis of a complete solar cell, with no free parameters, to deduce the multilayer solar cell structure non-invasively and simulate optical light absorption in each of the layer components. In the case of high efficiency CIGS solar cells, with minimal electronic losses, QE spectra are predicted from the sum of optical absorption in the active layer components. For such solar cells with ideal photo-generated charge carrier collection, the SE-predicted QE spectra are excellent representation of the measured ones. Since the QE spectra as well as the short circuit current density (Jsc) can be calculated directly from SE analysis results, then the predicted QE from SE can be compared with the experimental QE to evaluate electronic losses based on the difference between the spectra. Moreover, the calculated Jsc can be used as a key parameter for the design and optimization of anti-reflection coating structures. Because the long term production potential of CIGS solar modules may be limited by the availability of indium, it becomes important to reduce the thickness of the CIGS absorber layer. Thickness reduction would reduce the quantity of indium required for production which would in turn reduce costs. A decrease in short-circuit current density (Jsc) is expected, however, upon thinning the CIGS absorber due to incomplete absorption. To clarify the limits of obtainable Jsc in ultra-thin CIGS solar cells with Mo back contacts, optical properties and multilayer structural data are deduced via spectroscopic ellipsometry analysis and used to predict the QE spectra and maximum obtainable Jsc values upon thinning the absorber. Moreover, SE-guided optical design of ultra-thin CIGS solar cells has been demonstrated. In the case of solar cells fabricated on Mo, thinning the absorber in a CIGS solar cell is associated with significant optical losses in the Mo containing back contact layers. This is due in part to the poor optical reflectance of Mo. Such optical losses may be reduced by employing a back contact design with improved reflectance. Thus, alternative novel solar cell structures with ultra-thin absorbers and improved back contact reflectance have been designed and investigated using SE and the optical modeling methods. In addition to optical losses, electronic losses in the ultra-thin solar cells have been evaluated. By separating the absorber layer into sub-layer regions (for example, near-junction, bulk, and near-back-contact) and varying carrier collection probability in these regions, the contribution of each region to the current can be estimated. Based on this separation, the origin of the electronic losses has been identified as near the back contact.

Optical Metrology for CIGS Solar Cell Manufacturing and its Cost Implications

NASA Astrophysics Data System (ADS)

Sunkoju, Sravan Kumar

Solar energy is a promising source of renewable energy which can meet the demand for clean energy in near future with advances in research in the field of photovoltaics and cost reduction by commercialization. Availability of a non-contact, in-line, real time robust process control strategies can greatly aid in reducing the gap between cell and module efficiencies, thereby leading to cost-effective large-scale manufacturing of high efficiency CIGS solar cells. In order to achieve proper process monitoring and control for the deposition of the functional layers of CuIn1-xGaxSe 2 (CIGS) based thin film solar cell, optical techniques such as spectroscopic reflectometry and polarimetry are advantageous because they can be set up in an unobtrusive manner in the manufacturing line, and collect data in-line and in-situ. The use of these techniques requires accurate optical models that correctly represent the properties of the layers being deposited. In this study, Spectroscopic ellipsometry (SE) has been applied for the characterization of each individual stage of CIGS layers deposited using the 3-stage co-evaporation process along with the other functional layers. Dielectric functions have been determined for the energy range from 0.7 eV to 5.1 eV. Critical-point line-shape analysis was used in this study to determine the critical point energies of the CIGS based layers. To control the compositional and thickness uniformity of all the functional layers during the fabrication of CIGS solar cells over large areas, multilayer photovoltaics (PV) stack optical models were developed with the help of extracted dielectric functions. In this study, mapping capability of RC2 spectroscopic ellipsometer was used to map all the functional layer thicknesses of a CIGS solar cell in order to probe the spatial non-uniformities that can affect the performance of a cell. The optical functions for each of the stages of CIGS 3-stage deposition process along with buffer layer and transparent conducting oxide (TCO) bi-layer, thus derived were used in a fiber optic-based spectroscopic reflectometry optical monitoring system installed in the pilot line at the PVMC's Halfmoon facility. Results obtained from this study show that the use of regular fiber optics, instead of polarization-maintaining fiber optics, is sufficient for the purpose of process monitoring. Also, the technique does not need to be used "in-situ", but the measurements can be taken in-line, and are applicable to a variety of deposition techniques used for different functional layers deposited on rigid or flexible substrates. In addition, effect of Cu concentration on the CIGS optical properties has been studied. Mixed CIGS/Cu2-xSe phase was observed at the surface at the end of the second stage of 3-stage deposition process, under Cu-rich conditions. A significant change in optical behavior of CIGS due to Cu2-xSe at the surface was observed under Cu-rich conditions, which can be used as end-point detection method to move from 2nd stage to 3rd stage in the deposition process. Developed optical functions were applied to in-line reflectance measurements not only to identify the Cu2-xSe phase at the surface but also to measure the thickness of the mixed CIGS/Cu2-xSe layer. This spectroscopic reflectometry based in-line process control technique can be used for end-point detection as well as to control thickness during the preparation of large area CIGS films. These results can assist in the development of optical process-control tools for the manufacturing of high quality CIGS based photovoltaic cells, increasing the uptime and yield of the production line. Finally, to understand the cost implications, low cost potential of two different deposition technologies has been studied on both rigid and flexible substrates with the help of cost analysis. Cost advantages of employing a contactless optics based process control technique have been investigated in order to achieve a low cost of < 0.5 $/W for CIGS module production. Based on cost analysis, one of the best strategies for achieving the low cost targets would be increasing manufacturing throughput, using roll-to-roll thin-film module manufacturing, with co-evaporation and chemical bath deposition processes for absorber and buffer layer respectively, while applying a low-cost process control technique such as spectroscopic reflectometry to improve module efficiencies and maintain high yield.

New insights into the Mo/Cu(In,Ga)Se2 interface in thin film solar cells: Formation and properties of the MoSe2 interfacial layer.

PubMed

Klinkert, T; Theys, B; Patriarche, G; Jubault, M; Donsanti, F; Guillemoles, J-F; Lincot, D

2016-10-21

Being at the origin of an ohmic contact, the MoSe 2 interfacial layer at the Mo/Cu(In,Ga)Se 2 interface in CIGS (Cu(In,Ga)Se 2 and related compounds) based solar cells has allowed for very high light-to-electricity conversion efficiencies up to 22.3%. This article gives new insights into the formation and the structural properties of this interfacial layer. Different selenization-steps of a Mo covered glass substrate prior to the CIGS deposition by co-evaporation led to MoSe 2 interfacial layers with varying thickness and orientation, as observed by x-ray diffraction and atomic resolution transmission electron microscopy. A novel model based on the anisotropy of the Se diffusion coefficient in MoSe 2 is proposed to explain the results. While the series resistance of finished CIGS solar cells is found to correlate with the MoSe 2 orientation, the adhesion forces between the CIGS absorber layer and the Mo substrate stay constant. Their counter-intuitive non-correlation with the configuration of the MoSe 2 interfacial layer is discussed and related to work from the literature.

Achieving 14.4% Alcohol-Based Solution-Processed Cu(In,Ga)(S,Se)2 Thin Film Solar Cell through Interface Engineering.

PubMed

Park, Gi Soon; Chu, Van Ben; Kim, Byoung Woo; Kim, Dong-Wook; Oh, Hyung-Suk; Hwang, Yun Jeong; Min, Byoung Koun

2018-03-28

An optimization of band alignment at the p-n junction interface is realized on alcohol-based solution-processed Cu(In,Ga)(S,Se) 2 (CIGS) thin film solar cells, achieving a power-conversion-efficiency (PCE) of 14.4%. To obtain a CIGS thin film suitable for interface engineering, we designed a novel "3-step chalcogenization process" for Cu 2- x Se-derived grain growth and a double band gap grading structure. Considering S-rich surface of the CIGS thin film, an alternative ternary (Cd,Zn)S buffer layer is adopted to build favorable "spike" type conduction band alignment instead of "cliff" type. Suppression of interface recombination is elucidated by comparing recombination activation energies using a dark J- V- T analysis.

Behavior of Photocarriers in the Light-Induced Metastable State in the p-n Heterojunction of a Cu(In,Ga)Se2 Solar Cell with CBD-ZnS Buffer Layer.

PubMed

Lee, Woo-Jung; Yu, Hye-Jung; Wi, Jae-Hyung; Cho, Dae-Hyung; Han, Won Seok; Yoo, Jisu; Yi, Yeonjin; Song, Jung-Hoon; Chung, Yong-Duck

2016-08-31

We fabricated Cu(In,Ga)Se2 (CIGS) solar cells with a chemical bath deposition (CBD)-ZnS buffer layer grown with varying ammonia concentrations in aqueous solution. The solar cell performance was degraded with increasing ammonia concentration, due to actively dissolved Zn atoms during CBD-ZnS precipitation. These formed interfacial defect states, such as hydroxide species in the CBD-ZnS film, and interstitial and antisite Zn defects at the p-n heterojunction. After light/UV soaking, the CIGS solar cell performance drastically improved, with a rise in fill factor. With the Zn-based buffer layer, the light soaking treatment containing blue photons induced a metastable state and enhanced the CIGS solar cell performance. To interpret this effect, we suggest a band structure model of the p-n heterojunction to explain the flow of photocarriers under white light at the initial state, and then after light/UV soaking. The determining factor is a p+ defect layer, containing an amount of deep acceptor traps, located near the CIGS surface. The p+ defect layer easily captures photoexcited electrons, and then when it becomes quasi-neutral, attracts photoexcited holes. This alters the barrier height and controls the photocurrent at the p-n junction, and fill factor values, determining the solar cell performance.

Preparation and characterization of ZnS thin films by the chemical bath deposition method (Conference Presentation)

NASA Astrophysics Data System (ADS)

Ando, Shizutoshi; Iwashita, Taisuke

2017-06-01

Nowadays, the conversion efficiency of Cu(In･Ga)Se2 (CIGS)-based solar cell already reached over 20%. CdS thin films prepared by chemical bath deposition (CBD) method are used for CIGS-based thin film solar cells as the buffer layer. Over the past several years, a considerable number of studies have been conducted on ZnS buffer layer prepared by CBD in order to improve in conversion efficiency of CIGS-based solar cells. In addition, application to CIGS-based solar cell of ZnS buffer layer is expected as an eco-friendly solar cell by cadmium-free. However, it was found that ZnS thin films prepared by CBD included ZnO or Zn(OH)2 as different phase [1]. Nakata et. al reported that the conversion efficiency of CIGS-based solar cell using ZnS buffer layer (CBD-ZnS/CIGS) reached over 18% [2]. The problem which we have to consider next is improvement in crystallinity of ZnS thin films prepared by CBD. In this work, we prepared ZnS thin films on quarts (Si02) and SnO2/glass substrates by CBD with the self-catalysis growth process in order to improve crystallinity and quality of CBD-ZnS thin films. The solution to use for CBD were prepared by mixture of 0.2M ZnI2 or ZnSO4, 0.6M (NH2)2CS and 8.0M NH3 aq. In the first, we prepared the particles of ZnS on Si02 or SnO2/glass substrates by CBD at 80° for 20 min as initial nucleus (1st step ). After that, the particles of ZnS on Si02 or SnO2/glass substrates grew up to be ZnS thin films by CBD method at 80° for 40 min again (2nd step). We found that the surface of ZnS thin films by CBD with the self-catalyst growth process was flat and smooth. Consequently, we concluded that the CBD technique with self-catalyst growth process in order to prepare the particles of ZnS as initial nucleus layer was useful for improvement of crystallinity of ZnS thin films on SnO2/glass. [1] J.Vidal et,al., Thin Solid Films 419 (2002) 118. [2] T.Nakata et.al., Jpn. J. Appl. Phys. 41(2B), L165-L167 (2002)

Influence of Post-Heat Treatment of ZnO:Al Transparent Electrode for Copper Indium Gallium Selenide Thin Film Solar Cell.

PubMed

Eom, Taewoo; Park, Jeong Eun; Park, Sang Yong; Park, Jeong Hoon; Bweupe, Jackson; Lim, Donggun

2018-09-01

Copper indium gallium selenide (CIGS) thin film solar cells have been regarded as a candidate for energy conversion devices owing to their high absorption coefficient, high temperature stability, and low cost. ZnO:Al thin film is commonly used in CIGS solar cells as a window layer. In this study, ZnO:Al films were deposited on glass under various post-heat temperature using RF sputtering to observe the characteristics of ZnO:Al films such as Hall mobility, carrier concentration, and resistivity; subsequently, the ZnO:Al films were applied to a CIGS solar cell as a window. CIGS solar cells fabricated with various ZnO:Al films were analyzed in order to investigate their influence. The test results showed that the improvement of ZnO:Al characteristics affects Jsc and Voc in the solar cell through reduced recombination and increase of optical property.

Quantum and conversion efficiencies optimization of superstrate CIGS thin-films solar cells using In2Se3 buffer layer

NASA Astrophysics Data System (ADS)

Bouchama, Idris; Boudour, Samah; Bouarissa, Nadir; Rouabah, Zahir

2017-10-01

In this present contribution, AMPS-1D device simulator is employed to study the performances of superstrate SLG/TCO/p-Cu(In,Ga)Se2(CIGS)/n-ODC/n-In2Se3/Metal thin film solar cells. The impact of the TCO and Metal work functions on the cell performance has been investigated. The combination of optical transparency and electrical property for TCO front contact layer is found to yield high efficiency. The obtained results show that the TCO work function should be large enough to achieve high conversion efficiency for superstrate CIGS solar cell. Nevertheless, it is desirable for Metal back contact layer to have low work function to prevent the effect of band bending in the n-In2Se3/Metal interface. Several TCOs materials and metals have been tested respectively as a front and back contact layers for superstrate CIGS solar cells. An efficiency of 20.18%, with Voc ≈ 0.71 V, Jsc ≈ 35.36 mA/cm2 and FF ≈ 80.42%, has been achieved with ZnSn2O3-based as TCO front contact layer. In the case of SnO2:F front contact and indium back contact layers, an efficiency of 16.31%, with Voc ≈ 0.64 V, Jsc ≈ 31.4 mA/cm2 and FF ≈ 79.4%, has been obtained. The present results of simulation suggest an improvement of superstrate CIGS solar cells efficiency for feasible fabrication.

Suppressing lossy-film-induced angular mismatches between reflectance and transmittance extrema: optimum optical designs of interlayers and AR coating for maximum transmittance into active layers of CIGS solar cells.

PubMed

Chang, Yin-Jung

2014-01-13

The investigation of optimum optical designs of interlayers and antireflection (AR) coating for achieving maximum average transmittance (T(ave)) into the CuIn(1-x)Ga(x)Se2 (CIGS) absorber of a typical CIGS solar cell through the suppression of lossy-film-induced angular mismatches is described. Simulated-annealing algorithm incorporated with rigorous electromagnetic transmission-line network approach is applied with criteria of minimum average reflectance (R(ave)) from the cell surface or maximum T(ave) into the CIGS absorber. In the presence of one MgF2 coating, difference in R(ave) associated with optimum designs based upon the two distinct criteria is only 0.3% under broadband and nearly omnidirectional incidence; however, their corresponding T(ave) values could be up to 14.34% apart. Significant T(ave) improvements associated with the maximum-T(ave)-based design are found mainly in the mid to longer wavelengths and are attributed to the largest suppression of lossy-film-induced angular mismatches over the entire CIGS absorption spectrum. Maximum-T(ave)-based designs with a MgF2 coating optimized under extreme deficiency of angular information is shown, as opposed to their minimum-R(ave)-based counterparts, to be highly robust to omnidirectional incidence.

Origin of reduced efficiency in high Ga concentration Cu(In,Ga)Se2 solar cell

NASA Astrophysics Data System (ADS)

Wei, S.-H.; Huang, B.; Deng, H.; Contreras, M. A.; Noufi, R.; Chen, S.; Wang, L. W.

2014-03-01

CuInSe2 (CIS) is one of the most attractive thin-film materials for solar cells. It is well know that alloying Ga into CIS forming Cu(In,Ga)Se2 (CIGS) alloy is crucial to achieve the high efficiency, but adding too much Ga will lead to a decline of the solar cell efficiency. The exact origin of this puzzling phenomenon is currently still under debate. Using first-principles method, we have systemically studied the structural and electronic properties of CIGS alloys. Our phase diagram calculations suggest that increasing growth temperature may not be a critical factor in enhancing the cell performance of CIGS under equilibrium growth condition. On the other hand, our defect calculations identify that high concentration of antisite defects MCu(M =In, Ga) rather than anion defects are the key deep-trap centers in CIGS. The more the Ga concentration in CIGS, the more harmful the deep-trap is. Self-compensation in CIGS, which forms 2VCu + MCudefect complexes, is found to be beneficial to quench the deep-trap levels induced by MCu in CIGS, especially at low Ga concentration. Unfortunately, the density of isolated MCu is quite high and cannot be largely converted into 2VCu + MCu complexes under thermal equilibrium condition. Thus, nonequilibrium growth conditions or low growth temperature that can suppress the formation of the deep-trap centers MCu may be necessary for improving the efficiency of CIGS solar cells with high Ga concentrations.

Extending the Endurance of Small Unmanned Aerial Vehicles Using Advanced Flexible Solar Cells

DTIC Science & Technology

2012-12-01

Ryburn for the distractions of fishing and golf . Gratitude to Maxwell for moral support and being the best running partner I could ever ask for, you...shortages and price swings without development of better collection techniques [32]. 3. CIGS Like CdTe, CIGS cells are named for the base material

Device Modeling and Characterization for CIGS Solar Cells

NASA Astrophysics Data System (ADS)

Song, Sang Ho

We studied the way to achieve high efficiency and low cost of CuIn1-xGaxSe2 (CIGS) solar cells. The Fowler-Nordheim (F-N) tunneling currents at low bias decreased the shunt resistances and degraded the fill factor and efficiency. The activation energies of majority traps were directly related with F-N tunneling currents by the energy barriers. Air anneals decreased the efficiency from 7.74% to 5.18% after a 150 °C, 1000 hour anneal. The decrease of shunt resistance due to F-N tunneling and the increase of series resistance degrade the efficiencies of solar cells. Air anneal reduces the free carrier densities by the newly generated Cu interstitial defects (Cui). Mobile Cui defects induce the metastability in CIGS solar cell. Since oxygen atoms are preferred to passivate the Se vacancies thus Cu interstitial defects explains well metastability of CIGS solar cells. Lattice mismatch and misfit stress between layers in CIGS solar cells can explain the particular effects of CIGS solar cells. The misfits of 35.08° rotated (220/204) CIGS to r-plane (102) MoSe2 layers are 1% ˜ -4% lower than other orientation and the lattice constants of two layers in short direction are matched at Ga composition x=0.35. This explains well the preferred orientation and the maximum efficiency of Ga composition effects. Misfit between CIGS and CdS generated the dislocations in CdS layer as the interface traps. Thermionic emission currents due to interface traps limit the open circuit voltage at high Ga composition. The trap densities were calculated by critical thickness and dislocation spacing and the numerical device simulation results were well matched with the experimental results. A metal oxide broken-gap p-n heterojunction is suggested for tunnel junction for multi-junction polycrystalline solar cells and we examined the characteristics of broken-gap tunnel junction by numerical simulation. Ballistic transport mechanism explains well I-V characteristics of broken-gap junction. P-type Cu2O and n-type In2O3 broken-gap heterojunction is effective with the CIGS tandem solar cells. The junction has linear I-V characteristics with moderate carrier concentration (2x1017 cm-3) and the resistance is lower than GaAs tunnel junction. The efficiency of a CGS/CIS tandem solar cells was 24.1% with buffer layers. And no significant degradations are expected due to broken gap junction.

Improving Efficiency of Multicrystalline Silicon and CIGS Solar Cells by Incorporating Metal Nanoparticles.

PubMed

Jeng, Ming-Jer; Chen, Zih-Yang; Xiao, Yu-Ling; Chang, Liann-Be; Ao, Jianping; Sun, Yun; Popko, Ewa; Jacak, Witold; Chow, Lee

2015-10-08

This work studies the use of gold (Au) and silver (Ag) nanoparticles in multicrystalline silicon (mc-Si) and copper-indium-gallium-diselenide (CIGS) solar cells. Au and Ag nanoparticles are deposited by spin-coating method, which is a simple and low cost process. The random distribution of nanoparticles by spin coating broadens the resonance wavelength of the transmittance. This broadening favors solar cell applications. Metal shadowing competes with light scattering in a manner that varies with nanoparticle concentration. Experimental results reveal that the mc-Si solar cells that incorporate Au nanoparticles outperform those with Ag nanoparticles. The incorporation of suitable concentration of Au and Ag nanoparticles into mc-Si solar cells increases their efficiency enhancement by 5.6% and 4.8%, respectively. Incorporating Au and Ag nanoparticles into CIGS solar cells improve their efficiency enhancement by 1.2% and 1.4%, respectively. The enhancement of the photocurrent in mc-Si solar cells is lower than that in CIGS solar cells, owing to their different light scattering behaviors and material absorption coefficients.

Improving Efficiency of Multicrystalline Silicon and CIGS Solar Cells by Incorporating Metal Nanoparticles

PubMed Central

Jeng, Ming-Jer; Chen, Zih-Yang; Xiao, Yu-Ling; Chang, Liann-Be; Ao, Jianping; Sun, Yun; Popko, Ewa; Jacak, Witold; Chow, Lee

2015-01-01

This work studies the use of gold (Au) and silver (Ag) nanoparticles in multicrystalline silicon (mc-Si) and copper-indium-gallium-diselenide (CIGS) solar cells. Au and Ag nanoparticles are deposited by spin-coating method, which is a simple and low cost process. The random distribution of nanoparticles by spin coating broadens the resonance wavelength of the transmittance. This broadening favors solar cell applications. Metal shadowing competes with light scattering in a manner that varies with nanoparticle concentration. Experimental results reveal that the mc-Si solar cells that incorporate Au nanoparticles outperform those with Ag nanoparticles. The incorporation of suitable concentration of Au and Ag nanoparticles into mc-Si solar cells increases their efficiency enhancement by 5.6% and 4.8%, respectively. Incorporating Au and Ag nanoparticles into CIGS solar cells improve their efficiency enhancement by 1.2% and 1.4%, respectively. The enhancement of the photocurrent in mc-Si solar cells is lower than that in CIGS solar cells, owing to their different light scattering behaviors and material absorption coefficients. PMID:28793599

Design and long-term monitoring of DSC/CIGS tandem solar module

NASA Astrophysics Data System (ADS)

Vildanova, M. F.; Nikolskaia, A. B.; Kozlov, S. S.; Shevaleevskiy, O. I.

2015-11-01

This paper describes the design and development of tandem dye-sensitized/Cu(In, Ga)Se (DSC/CIGS) PV modules. The tandem PV module comprised of the top DSC module and a bottom commercial 0,8 m2 CIGS module. The top DSC module was made of 10 DSC mini-modules with the field size of 20 × 20 cm2 each. Tandem DSC/CIGS PV modules were used for providing the long-term monitoring of energy yield and electrical parameters in comparison with standalone CIGS modules under outdoor conditions. The outdoor test facility, containing solar modules of both types and a measurement unit, was located on the roof of the Institute of Biochemical Physics in Moscow. The data obtained during monitoring within the 2014 year period has shown the advantages of the designed tandem DSC/CIGS PV-modules over the conventional CIGS modules, especially for cloudy weather and low-intensity irradiation conditions.

Employing Si solar cell technology to increase efficiency of ultra-thin Cu(In,Ga)Se2 solar cells.

PubMed

Vermang, Bart; Wätjen, Jörn Timo; Fjällström, Viktor; Rostvall, Fredrik; Edoff, Marika; Kotipalli, Ratan; Henry, Frederic; Flandre, Denis

2014-10-01

Reducing absorber layer thickness below 500 nm in regular Cu(In,Ga)Se 2 (CIGS) solar cells decreases cell efficiency considerably, as both short-circuit current and open-circuit voltage are reduced because of incomplete absorption and high Mo/CIGS rear interface recombination. In this work, an innovative rear cell design is developed to avoid both effects: a highly reflective rear surface passivation layer with nano-sized local point contact openings is employed to enhance rear internal reflection and decrease the rear surface recombination velocity significantly, as compared with a standard Mo/CIGS rear interface. The formation of nano-sphere shaped precipitates in chemical bath deposition of CdS is used to generate nano-sized point contact openings. Evaporation of MgF 2 coated with a thin atomic layer deposited Al 2 O 3 layer, or direct current magnetron sputtering of Al 2 O 3 are used as rear surface passivation layers. Rear internal reflection is enhanced substantially by the increased thickness of the passivation layer, and also the rear surface recombination velocity is reduced at the Al 2 O 3 /CIGS rear interface. (MgF 2 /)Al 2 O 3 rear surface passivated ultra-thin CIGS solar cells are fabricated, showing an increase in short circuit current and open circuit voltage compared to unpassivated reference cells with equivalent CIGS thickness. Accordingly, average solar cell efficiencies of 13.5% are realized for 385 nm thick CIGS absorber layers, compared with 9.1% efficiency for the corresponding unpassivated reference cells.

Employing Si solar cell technology to increase efficiency of ultra-thin Cu(In,Ga)Se2 solar cells

PubMed Central

Vermang, Bart; Wätjen, Jörn Timo; Fjällström, Viktor; Rostvall, Fredrik; Edoff, Marika; Kotipalli, Ratan; Henry, Frederic; Flandre, Denis

2014-01-01

Reducing absorber layer thickness below 500 nm in regular Cu(In,Ga)Se2 (CIGS) solar cells decreases cell efficiency considerably, as both short-circuit current and open-circuit voltage are reduced because of incomplete absorption and high Mo/CIGS rear interface recombination. In this work, an innovative rear cell design is developed to avoid both effects: a highly reflective rear surface passivation layer with nano-sized local point contact openings is employed to enhance rear internal reflection and decrease the rear surface recombination velocity significantly, as compared with a standard Mo/CIGS rear interface. The formation of nano-sphere shaped precipitates in chemical bath deposition of CdS is used to generate nano-sized point contact openings. Evaporation of MgF2 coated with a thin atomic layer deposited Al2O3 layer, or direct current magnetron sputtering of Al2O3 are used as rear surface passivation layers. Rear internal reflection is enhanced substantially by the increased thickness of the passivation layer, and also the rear surface recombination velocity is reduced at the Al2O3/CIGS rear interface. (MgF2/)Al2O3 rear surface passivated ultra-thin CIGS solar cells are fabricated, showing an increase in short circuit current and open circuit voltage compared to unpassivated reference cells with equivalent CIGS thickness. Accordingly, average solar cell efficiencies of 13.5% are realized for 385 nm thick CIGS absorber layers, compared with 9.1% efficiency for the corresponding unpassivated reference cells. PMID:26300619

Ultrawide Spectral Response of CIGS Solar Cells Integrated with Luminescent Down-Shifting Quantum Dots.

PubMed

Jeong, Ho-Jung; Kim, Ye-Chan; Lee, Soo Kyung; Jeong, Yonkil; Song, Jin-Won; Yun, Ju-Hyung; Jang, Jae-Hyung

2017-08-02

Conventional Cu(In 1-x ,Ga x )Se 2 (CIGS) solar cells exhibit poor spectral response due to parasitic light absorption in the window and buffer layers at the short wavelength range between 300 and 520 nm. In this study, the CdSe/CdZnS core/shell quantum dots (QDs) acting as a luminescent down-shifting (LDS) layer were inserted between the MgF 2 antireflection coating and the window layer of the CIGS solar cell to improve light harvesting in the short wavelength range. The LDS layer absorbs photons in the short wavelength range and re-emits photons in the 609 nm range, which are transmitted through the window and buffer layer and absorbed in the CIGS layer. The average external quantum efficiency in the parasitic light absorption region (300-520 nm) was enhanced by 51%. The resulting short circuit current density of 34.04 mA/cm 2 and power conversion efficiency of 14.29% of the CIGS solar cell with the CdSe/CdZnS QDs were improved by 4.35 and 3.85%, respectively, compared with those of the conventional solar cells without QDs.

Device physics of Cu(In,Ga)Se2 solar cells for long-term operation

NASA Astrophysics Data System (ADS)

Nishinaga, J.; Shibata, H.

2017-02-01

The degradation mechanism of Cu(In,Ga)Se2 (CIGS) solar cells on exposure to air has been investigated. Exposure to air at room temperature slightly reduces the conversion efficiency of CIGS solar cells, and the conversion efficiency decreases significantly under damp heat testing at 85 °C and 85% relative humidity due to low shunt resistance. On the other hand, shunt resistance increases after dry nitrogen heating. Therefore, oxygen and humidity should degenerate the solar cell performance. The low shunt resistance and conversion efficiency are completely recovered after removing the side edges of the CIGS solar cells by mechanical scribing. These results suggest that low-resistive layers are formed on the sidewalls of the solar cells during damp heat testing. The low-resistive layers on the sidewalls are identified to be molybdenum oxides and sodium molybdate by Auger electron spectroscopy. After etching the oxides on the sidewalls by alkaline solution, the saturation current density and ideality factor are confirmed to be improved. These results suggest that metal oxides on the sidewalls of CIGS solar cells may act as recombination centers.

Improving the efficiency of copper indium gallium (Di-)selenide (CIGS) solar cells through integration of a moth-eye textured resist with a refractive index similar to aluminum doped zinc oxide

NASA Astrophysics Data System (ADS)

Burghoorn, M.; Kniknie, B.; van Deelen, J.; Xu, M.; Vroon, Z.; van Ee, R.; van de Belt, R.; Buskens, P.

2014-12-01

Textured transparent conductors are widely used in thin-film silicon solar cells. They lower the reflectivity at interfaces between different layers in the cell and/or cause an increase in the path length of photons in the Si absorber layer, which both result in an increase in the number of absorbed photons and, consequently, an increase in short-circuit current density (Jsc) and cell efficiency. Through optical simulations, we recently obtained strong indications that texturing of the transparent conductor in copper indium gallium (di-)selenide (CIGS) solar cells is also optically advantageous. Here, we experimentally demonstrate that the Jsc and efficiency of CIGS solar cells with an absorber layer thickness (dCIGS) of 0.85 μm, 1.00 μm and 2.00 μm increase through application of a moth-eye textured resist with a refractive index that is sufficiently similar to AZO (nresist = 1.792 vs. nAZO = 1.913 at 633 nm) to avoid large optical losses at the resist-AZO interface. On average, Jsc increases by 7.2%, which matches the average reduction in reflection of 7.0%. The average relative increase in efficiency is slightly lower (6.0%). No trend towards a larger relative increase in Jsc with decreasing dCIGS was observed. Ergo, the increase in Jsc can be fully explained by the reduction in reflection, and we did not observe any increase in Jsc based on an increased photon path length.

CIGS2 Thin-Film Solar Cells on Flexible Foils for Space Power

NASA Technical Reports Server (NTRS)

Dhere, Neelkanth G.; Ghongadi, Shantinath R.; Pandit, Mandar B.; Jahagirdar, Anant H.; Scheiman, David

2002-01-01

CuIn(1-x)Ga(x)S2 (CIGS2) thin-film solar cells are of interest for space power applications because of the near optimum bandgap for AM0 solar radiation in space. CIGS2 thin film solar cells on flexible stainless steel (SS) may be able to increase the specific power by an order of magnitude from the current level of 65 Wkg(sup -1). CIGS solar cells are superior to the conventional silicon and gallium arsenide solar cells in the space radiation environment. This paper presents research efforts for the development of CIGS2 thin-film solar cells on 127 micrometers and 20 micrometers thick, bright-annealed flexible SS foil for space power. A large-area, dual-chamber, inline thin film deposition system has been fabricated. The system is expected to provide thickness uniformity of plus or minus 2% over the central 5" width and plus or minus 3% over the central 6" width. During the next phase, facilities for processing larger cells will be acquired for selenization and sulfurization of metallic precursors and for heterojunction CdS layer deposition both on large area. Small area CIGS2 thin film solar cells are being prepared routinely. Cu-rich Cu-Ga/In layers were sputter-deposited on unheated Mo-coated SS foils from CuGa (22%) and In targets. Well-adherent, large-grain Cu-rich CIGS2 films were obtained by sulfurization in a Ar: H2S 1:0.04 mixture and argon flow rate of 650 sccm, at the maximum temperature of 475 C for 60 minutes with intermediate 30 minutes annealing step at 120 C. Samples were annealed at 500 C for 10 minutes without H2S gas flow. The intermediate 30 minutes annealing step at 120 C was changed to 135 C. p-type CIGS2 thin films were obtained by etching the Cu-rich layer segregated at the surface using dilute KCN solution. Solar cells were completed by deposition of CdS heterojunction partner layer by chemical bath deposition, transparent-conducting ZnO/ZnO: Al window bilayer by RF sputtering, and vacuum deposition of Ni/Al contact fingers through metal mask. PV parameters of a CIGS2 solar cell on 127 micrometers thick SS flexible foil measured under AM 0 conditions at NASA GRC were: V(sub oc) = 802.9 mV, J(sub sc) = 25.07 mA per square centimeters, FF = 60.06%, and efficiency 0 = 8.84%. For this cell, AM 1.5 PV parameters measured at NREL were: V(sub oc) = 788 mV, J(sub sc) = 19.78 mA per square centimeter, FF = 59.44%, efficiency 0 = 9.26%. Quantum efficiency curve showed a sharp QE cutoff equivalent to CIGS2 bandgap of approximately 1.50 eV, fairly close to the optimum value for efficient AM0 PV conversion in the space.

In-Situ Probing Plasmonic Energy Transfer in Cu(In, Ga)Se2 Solar Cells by Ultrabroadband Femtosecond Pump-Probe Spectroscopy.

PubMed

Chen, Shih-Chen; Wu, Kaung-Hsiung; Li, Jia-Xing; Yabushita, Atsushi; Tang, Shih-Han; Luo, Chih Wei; Juang, Jenh-Yih; Kuo, Hao-Chung; Chueh, Yu-Lun

2015-12-18

In this work, we demonstrated a viable experimental scheme for in-situ probing the effects of Au nanoparticles (NPs) incorporation on plasmonic energy transfer in Cu(In, Ga)Se2 (CIGS) solar cells by elaborately analyzing the lifetimes and zero moment for hot carrier relaxation with ultrabroadband femtosecond pump-probe spectroscopy. The signals of enhanced photobleach (PB) and waned photoinduced absorption (PIA) attributable to surface plasmon resonance (SPR) of Au NPs were in-situ probed in transient differential absorption spectra. The results suggested that substantial carriers can be excited from ground state to lower excitation energy levels, which can reach thermalization much faster with the existence of SPR. Thus, direct electron transfer (DET) could be implemented to enhance the photocurrent of CIGS solar cells. Furthermore, based on the extracted hot carrier lifetimes, it was confirmed that the improved electrical transport might have been resulted primarily from the reduction in the surface recombination of photoinduced carriers through enhanced local electromagnetic field (LEMF). Finally, theoretical calculation for resonant energy transfer (RET)-induced enhancement in the probability of exciting electron-hole pairs was conducted and the results agreed well with the enhanced PB peak of transient differential absorption in plasmonic CIGS film. These results indicate that plasmonic energy transfer is a viable approach to boost high-efficiency CIGS solar cells.

Effect of Selenization Processes on CIGS Solar Cell Performance.

PubMed

Wu, C H; Wu, P W; Chen, J H; Kao, J Y; Hsu, C Y

2018-07-01

Cu(In, Ga)Se2 (CIGS) films were fabricated by a two-step process method using sputtering from Cu0.7Ga0.3 and In targets. The metallic precursor structures of In/CuGa/In were prepared, and CuGa film was adjusted to the thicknesses of 150, 200, 250 and 300 nm, in order to optimize the CIGS film. After selenization, three independent CIGS (112), CIGS (220/204) and CIGS (312/116) began to crystallize at ~280 °C and phase peaks continued growing until 560 °C. Experimental results showed that with a single stage selenization method, the excessive stoichiometry of the CIGS films was obtained. Using three sequential stages for the selenization process, with a annealing time of 20 min, the stoichiometry of the CIGS absorbers with the Cu/(In + Ga) and Ga/(In + Ga) showed atomic ratios of 0.94 and 0.34, respectively. The intensity of the (112) XRD diffraction peak became stronger, indicating an improvement in the crystallinity. Raman spectra of CIGS absorbers showed a main peak (174 cm-1) and two weak signals (212 and 231 cm-1). TEM image for electron diffraction pattern showed that the grains were randomly oriented. CIGS solar cell device prepared with a proper selenization, a maximum efficiency of 12.45% was obtained.

Physics-Based Compact Model for CIGS and CdTe Solar Cells: From Voltage-Dependent Carrier Collection to Light-Enhanced Reverse Breakdown: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Xingshu; Alam, Muhammad Ashraful; Raguse, John

2015-10-15

In this paper, we develop a physics-based compact model for copper indium gallium diselenide (CIGS) and cadmium telluride (CdTe) heterojunction solar cells that attributes the failure of superposition to voltage-dependent carrier collection in the absorber layer, and interprets light-enhanced reverse breakdown as a consequence of tunneling-assisted Poole-Frenkel conduction. The temperature dependence of the model is validated against both simulation and experimental data for the entire range of bias conditions. The model can be used to characterize device parameters, optimize new designs, and most importantly, predict performance and reliability of solar panels including the effects of self-heating and reverse breakdown duemore » to partial-shading degradation.« less

Designing novel thin film polycrystalline solar cells for high efficiency: sandwich CIGS and heterojunction perovskite

NASA Astrophysics Data System (ADS)

Wang, Tianyue; Chen, Jiewei; Wu, Gaoxiang; Song, Dandan; Li, Meicheng

2017-01-01

Heterojunction and sandwich architectures are two new-type structures with great potential for solar cells. Specifically, the heterojunction structure possesses the advantages of efficient charge separation but suffers from band offset and large interface recombination; the sandwich configuration is favorable for transferring carriers but requires complex fabrication process. Here, we have designed two thin-film polycrystalline solar cells with novel structures: sandwich CIGS and heterojunction perovskite, referring to the advantages of the architectures of sandwich perovskite (standard) and heterojunction CIGS (standard) solar cells, respectively. A reliable simulation software wxAMPS is used to investigate their inherent characteristics with variation of the thickness and doping density of absorber layer. The results reveal that sandwich CIGS solar cell is able to exhibit an optimized efficiency of 20.7%, which is much higher than the standard heterojunction CIGS structure (18.48%). The heterojunction perovskite solar cell can be more efficient employing thick and doped perovskite films (16.9%) than these typically utilizing thin and weak-doping/intrinsic perovskite films (9.6%). This concept of structure modulation proves to be useful and can be applicable for other solar cells. Project supported by the National High-Tech R&D Program of China (No. 2015AA034601), the National Natural Science Foundation of China (Nos. 91333122, 61204064, 51202067, 51372082, 51402106, 11504107), the Ph.D. Programs Foundation of Ministry of Education of China (Nos. 20120036120006, 20130036110012), the Par-Eu Scholars Program, and the Fundamental Research Funds for the Central Universities.

Improving the efficiency of copper indium gallium (Di-)selenide (CIGS) solar cells through integration of a moth-eye textured resist with a refractive index similar to aluminum doped zinc oxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burghoorn, M.; Kniknie, B.; Deelen, J. van

2014-12-15

Textured transparent conductors are widely used in thin-film silicon solar cells. They lower the reflectivity at interfaces between different layers in the cell and/or cause an increase in the path length of photons in the Si absorber layer, which both result in an increase in the number of absorbed photons and, consequently, an increase in short-circuit current density (J{sub sc}) and cell efficiency. Through optical simulations, we recently obtained strong indications that texturing of the transparent conductor in copper indium gallium (di-)selenide (CIGS) solar cells is also optically advantageous. Here, we experimentally demonstrate that the J{sub sc} and efficiency ofmore » CIGS solar cells with an absorber layer thickness (d{sub CIGS}) of 0.85 μm, 1.00 μm and 2.00 μm increase through application of a moth-eye textured resist with a refractive index that is sufficiently similar to AZO (n{sub resist} = 1.792 vs. n{sub AZO} = 1.913 at 633 nm) to avoid large optical losses at the resist-AZO interface. On average, J{sub sc} increases by 7.2%, which matches the average reduction in reflection of 7.0%. The average relative increase in efficiency is slightly lower (6.0%). No trend towards a larger relative increase in J{sub sc} with decreasing d{sub CIGS} was observed. Ergo, the increase in J{sub sc} can be fully explained by the reduction in reflection, and we did not observe any increase in J{sub sc} based on an increased photon path length.« less

10.3%-efficient submicron-thick Cu(In,Ga)Se2 solar cells with absorber fabricated by sputtering In2Se3, CuGaSe2 and Cu2Se targets

NASA Astrophysics Data System (ADS)

Peng, Xiao; Zhao, Ming; Zhuang, Daming; Sun, Rujun; Zhang, Leng; Wei, Yaowei; Lv, Xunyan; Wu, Yixuan; Ren, Guoan

2018-06-01

We reported a new method to fabricate submicron-thick CIGS with smooth surface by sputtering In2Se3, CuGaSe2 and Cu2Se targets with post-selenization. The influence of gallium content on the properties of CIGS thin film was evaluated by the crystallinity and the cells performance. The most suitable value of Ga content in our submicron-thick CIGS is 0.32 and cells based on it demonstrated the highest efficiency of 10.3%.

Wet Pretreatment-Induced Modification of Cu(In,Ga)Se2/Cd-Free ZnTiO Buffer Interface.

PubMed

Hwang, Suhwan; Larina, Liudmila; Lee, Hojin; Kim, Suncheul; Choi, Kyoung Soon; Jeon, Cheolho; Ahn, Byung Tae; Shin, Byungha

2018-06-20

We report a novel Cd-free ZnTiO buffer layer deposited by atomic layer deposition for Cu(In,Ga)Se 2 (CIGS) solar cells. Wet pretreatments of the CIGS absorbers with NH 4 OH, H 2 O, and/or aqueous solution of Cd 2+ ions were explored to improve the quality of the CIGS/ZnTiO interface, and their effects on the chemical state of the absorber and the final performance of Cd-free CIGS devices were investigated. X-ray photoelectron spectroscopy (XPS) analysis revealed that the aqueous solution etched away sodium compounds accumulated on the CIGS surface, which was found to be detrimental for solar cell operation. Wet treatment with NH 4 OH solution led to a reduced photocurrent, which was attributed to the thinning (or removal) of an ordered vacancy compound (OVC) layer on the CIGS surface as evidenced by an increased Cu XPS peak intensity after the NH 4 OH treatment. However, the addition of Cd 2+ ions to the NH 4 OH aqueous solution suppressed the etching of the OVC by NH 4 OH, explaining why such a negative effect of NH 4 OH is not present in the conventional chemical bath deposition of CdS. The band alignment at the CIGS/ZnTiO interface was quantified using XPS depth profile measurements. A small cliff-like conduction band offset of -0.11 eV was identified at the interface, which indicates room for further improvement of efficiency of the CIGS/ZnTiO solar cells once the band alignment is altered to a slight spike by inserting a passivation layer with a higher conduction band edge than ZnTiO. Combination of the small cliff conduction band offset at the interface, removal of the Na compound via water, and surface doping by Cd ions allowed the application of ZnTiO buffer to CIGS treated with Cd solutions, exhibiting an efficiency of 80% compared to that of a reference CIGS solar cell treated with the CdS.

Photovoltaic Performance and Interface Behaviors of Cu(In,Ga)Se2 Solar Cells with a Sputtered-Zn(O,S) Buffer Layer by High-Temperature Annealing.

PubMed

Wi, Jae-Hyung; Kim, Tae Gun; Kim, Jeong Won; Lee, Woo-Jung; Cho, Dae-Hyung; Han, Won Seok; Chung, Yong-Duck

2015-08-12

We selected a sputtered-Zn(O,S) film as a buffer material and fabricated a Cu(In,Ga)Se2 (CIGS) solar cell for use in monolithic tandem solar cells. A thermally stable buffer layer was required because it should withstand heat treatment during processing of top cell. Postannealing treatment was performed on a CIGS solar cell in vacuum at temperatures from 300-500 °C to examine its thermal stability. Serious device degradation particularly in VOC was observed, which was due to the diffusion of thermally activated constituent elements. The elements In and Ga tend to out-diffuse to the top surface of the CIGS, while Zn diffuses into the interface of Zn(O,S)/CIGS. Such rearrangement of atomic fractions modifies the local energy band gap and band alignment at the interface. The notch-shape induced at the interface after postannealing could function as an electrical trap during electron transport, which would result in the reduction of solar cell efficiency.

Electron-Selective TiO 2 Contact for Cu(In,Ga)Se 2 Solar Cells

DOE PAGES

Hsu, Weitse; Sutter-Fella, Carolin M.; Hettick, Mark; ...

2015-11-03

The non-toxic and wide bandgap material TiO 2 is explored as an n-type buffer layer on p-type Cu(In,Ga)Se 2 (CIGS) absorber layer for thin film solar cells. The amorphous TiO 2 thin film deposited by atomic layer deposition process at low temperatures shows conformal coverage on the CIGS absorber layer. Solar cells from non-vacuum deposited CIGS absorbers with TiO 2 buffer layer result in a high short-circuit current density of 38.9 mA/cm 2 as compared to 36.9 mA/cm 2 measured in the reference cell with CdS buffer layer, without compromising open-circuit voltage. The significant photocurrent gain, mainly in the UVmore » part of the spectrum, can be attributed to the low parasitic absorption loss in the ultrathin TiO 2 layer (~10 nm) with a larger bandgap of 3.4 eV compared to 2.4 eV of the traditionally used CdS. Overall the solar cell conversion efficiency was improved from 9.5% to 9.9% by substituting the CdS by TiO 2 on an active cell area of 10.5 mm2. In conclusion, optimized TiO 2/CIGS solar cells show excellent long-term stability. The results imply that TiO 2 is a promising buffer layer material for CIGS solar cells, avoiding the toxic CdS buffer layer with added performance advantage.« less

Recycling of high purity selenium from CIGS solar cell waste materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gustafsson, Anna M.K., E-mail: anna.gustafsson@chalmers.se; Foreman, Mark R.StJ.; Ekberg, Christian

Highlights: • A new method for recycling of selenium from CIGS solar cell materials is presented. • Separation of selenium as selenium dioxide after heating in oxygen atmosphere. • Complete selenium separation after oxidation of <63 μm particles at 800 °C for 1 h. • After reduction of selenium dioxide the selenium purity was higher than 99.999 wt%. - Abstract: Copper indium gallium diselenide (CIGS) is a promising material in thin film solar cell production. To make CIGS solar cells more competitive, both economically and environmentally, in comparison to other energy sources, methods for recycling are needed. In addition tomore » the generally high price of the material, significant amounts of the metals are lost in the manufacturing process. The feasibility of recycling selenium from CIGS through oxidation at elevated temperatures was therefore examined. During oxidation gaseous selenium dioxide was formed and could be separated from the other elements, which remained in solid state. Upon cooling, the selenium dioxide sublimes and can be collected as crystals. After oxidation for 1 h at 800 °C all of the selenium was separated from the CIGS material. Two different reduction methods for reduction of the selenium dioxide to selenium were tested. In the first reduction method an organic molecule was used as the reducing agent in a Riley reaction. In the second reduction method sulphur dioxide gas was used. Both methods resulted in high purity selenium. This proves that the studied selenium separation method could be the first step in a recycling process aimed at the complete separation and recovery of high purity elements from CIGS.« less

The Effect of Interface Cracks on the Electrical Performance of Solar Cells

NASA Astrophysics Data System (ADS)

Kim, Hansung; Tofail, Md. Towfiq; John, Ciby

2018-04-01

Among a variety of solar cell types, thin-film solar cells have been rigorously investigated as cost-effective and efficient solar cells. In many cases, flexible solar cells are also fabricated as thin films and undergo frequent stress due to the rolling and bending modes of applications. These frequent motions result in crack initiation and propagation (including delamination) in the thin-film solar cells, which cause degradation in efficiency. Reliability evaluation of solar cells is essential for developing a new type of solar cell. In this paper, we investigated the effect of layer delamination and grain boundary crack on 3D thin-film solar cells. We used finite element method simulation for modeling of both electrical performance and cracked structure of 3D solar cells. Through simulations, we quantitatively calculated the effect of delamination length on 3D copper indium gallium diselenide (CIGS) solar cell performance. Moreover, it was confirmed that the grain boundary of CIGS could improve the solar cell performance and that grain boundary cracks could decrease cell performance by altering the open circuit voltage. In this paper, the investigated material is a CIGS solar cell, but our method can be applied to general polycrystalline solar cells.

High-Efficiency Polycrystalline Thin Film Tandem Solar Cells.

PubMed

Kranz, Lukas; Abate, Antonio; Feurer, Thomas; Fu, Fan; Avancini, Enrico; Löckinger, Johannes; Reinhard, Patrick; Zakeeruddin, Shaik M; Grätzel, Michael; Buecheler, Stephan; Tiwari, Ayodhya N

2015-07-16

A promising way to enhance the efficiency of CIGS solar cells is by combining them with perovskite solar cells in tandem devices. However, so far, such tandem devices had limited efficiency due to challenges in developing NIR-transparent perovskite top cells, which allow photons with energy below the perovskite band gap to be transmitted to the bottom cell. Here, a process for the fabrication of NIR-transparent perovskite solar cells is presented, which enables power conversion efficiencies up to 12.1% combined with an average sub-band gap transmission of 71% for photons with wavelength between 800 and 1000 nm. The combination of a NIR-transparent perovskite top cell with a CIGS bottom cell enabled a tandem device with 19.5% efficiency, which is the highest reported efficiency for a polycrystalline thin film tandem solar cell. Future developments of perovskite/CIGS tandem devices are discussed and prospects for devices with efficiency toward and above 27% are given.

Molybdenum, molybdenum oxides, and their electrochemistry.

PubMed

Saji, Viswanathan S; Lee, Chi-Woo

2012-07-01

The electrochemical behaviors of molybdenum and its oxides, both in bulk and thin film dimensions, are critical because of their widespread applications in steels, electrocatalysts, electrochromic materials, batteries, sensors, and solar cells. An important area of current interest is electrodeposited CIGS-based solar cells where a molybdenum/glass electrode forms the back contact. Surprisingly, the basic electrochemistry of molybdenum and its oxides has not been reviewed with due attention. In this Review, we assess the scattered information. The potential and pH dependent active, passive, and transpassive behaviors of molybdenum in aqueous media are explained. The major surface oxide species observed, reversible redox transitions of the surface oxides, pseudocapacitance and catalytic reduction are discussed along with carefully conducted experimental results on a typical molybdenum glass back contact employed in CIGS-based solar cells. The applications of molybdenum oxides and the electrodeposition of molybdenum are briefly reviewed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of thermal annealing on the redistribution of alkali metals in Cu(In,Ga)Se2 solar cells on glass substrate

NASA Astrophysics Data System (ADS)

Kamikawa, Yukiko; Nishinaga, Jiro; Ishizuka, Shogo; Tayagaki, Takeshi; Guthrey, Harvey; Shibata, Hajime; Matsubara, Koji; Niki, Shigeru

2018-03-01

The precise control of alkali-metal concentrations in Cu(In,Ga)Se2 (CIGS) solar cells via post deposition treatment (PDT) has recently attracted attention. When PDT is performed at an elevated temperature, an accompanying annealing effect is expected. Here, we investigate how thermal annealing affects the redistribution of alkali metals in CIGS solar cells on glass substrates and the properties of the solar cells. In addition, we investigate the origin of non-homogeneous alkali-metal depth profiles that are typical of CIGS grown using a three-stage process. In particular, we use secondary-ion mass spectrometry measurements of the ion concentration as a function of distance from the CIGS surface to investigate the impact of thermal annealing on the distribution of alkali metals (Na, Ka, and Rb) and constituent elements (Ga and In) in the CIGS absorbers. We find that the depth profiles of the alkali metals strongly reflect the density of sites that tend to accommodate alkali metals, i.e., vacancies. Annealing at elevated temperature caused a redistribution of the alkali metals. The thermal-diffusion kinetics of alkali metals depends strongly on the species involved. We introduced low flux potassium fluoride (KF) to study a side effect of KF-PDT, i.e., Na removal from CIGS, separately from its predominant effects such as surface modification. When sufficient amounts of Na are supplied from the soda lime glass via annealing at an elevated temperature, the negative effect was not apparent. Conversely, when the Na supply was not sufficient, it caused a deterioration of the photovoltaic properties.

Determination of the Electrical Junction in Cu(In, Ga)Se2 and Cu2ZnSnSe4 Solar Cells with 20-nm Spatial Resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Chuanxiao; Jiang, Chun-Sheng; Moutinho, Helio

2016-11-21

We located the electrical junction (EJ) of Cu(In, Ga)Se2 (CIGS) and Cu2ZnSnSe4 (CZTS) solar cells with ~20-nm accuracy using a scanning capacitance spectroscopy (SCS) technique. A procedure was developed to prepare the cross-sectional samples and grow critical high-quality insulating layers for the SCS measurement. We found that CIGS has a buried homojunction with the EJ located at ~40 nm inside the CIGS/CdS interface. An n-type CIGS was probed in the region 10-30 nm away from the interface. By contrast, the CZTS/CdS cells have a heterointerface junction with a shallower EJ (~20 nm) than CIGS. The EJ is ~20 nm frommore » the CZTS/CdS interface, which is consistent with asymmetrical carrier concentrations of the p-CZTS and n-CdS in a heterojunction cell. The unambiguous determination of the junction locations helped explain the large open circuit voltage difference between the state-of-the-art devices of CIGS and CZTS.« less

Cu(In,Ga)(Se,S)2 solar cell research in Solar Frontier: Progress and current status

NASA Astrophysics Data System (ADS)

Kato, Takuya

2017-04-01

As the largest manufacturer of Cu(In,Ga)(Se,S)2 (CIGS) thin-film photovoltaic modules with more than 1 GW/year production volume, Solar Frontier K.K. has continuously improved module performance and small-area cell efficiencies in the laboratory. Because of our low-cost and environmentally-friendly process, Solar Frontier’s CIGS is a promising technology for the mass production of photovoltaic modules to fill ever-increasing demand. Recently we have achieved certified efficiencies of 22.3 and 22.0% on CdS-buffered and Cd-free buffered small-area cells, respectively, as well as 18.6% on a Cd-free mini-module. In this paper, a review of our CIGS technology and recent progress on the development of the module and the small-area cell is presented.

Optical Coating for Improvement in Thermal Radiative Properties of Cu (In, Ga) Se2 Thin Film Solar Cells for Space Applications

NASA Astrophysics Data System (ADS)

Shimazaki, Kazunori; Kawakita, Shirou; Imaizumi, Mitsuru; Kuwajima, Saburou; Sakurai, Keiichiro; Matsubara, Koji; Niki, Sigeru

2005-05-01

Optical coating on Cu(In, Ga)Se2 thin film solar cells, which have high radiation tolerance, is investigated in order to improve their radiative properties for thermal balance in space. Due to low thermal emissivity, the temperature of the CIGS solar cell is expected to exceed the allowable limit if no coating is applied. Evaporated single-layer coating of silicon dioxide and additional over-layer coatings on the CIGS solar cells increase the emissivity from 0.18 to 0.75. The coating with the over-layer coatings realizes higher emissivity with less thickness than that of the single SiO2 coating. In addition, optical coatings reflecting UV rays and infrared radiation are designed and evaporated on the cells to control solar input. The developed optical coatings could give the CIGS solar cells appropriate thermal radiative properties for space applications without any degradations of the cell performance.

Review of grain interior, grain boundary, and interface effects of K in CIGS solar cells: Mechanisms for performance enhancement

DOE PAGES

Muzzillo, Christopher P.

2017-07-16

Introducing K into Cu(In,Ga)(Se,S) 2 (CIGS) absorbers has led to recent world record power conversion efficiencies for thin film polycrystalline solar cells. In this work, the diverse phenomena associated with K in CIGS were reviewed, and overarching mechanisms were identified. The effects of K depend on its distribution among grain interiors (GIs), grain boundaries (GBs), and interfaces. High substrate Na and low temperature favor GI K incorporation, while low Na and high temperature favor segregation of K at GBs. Depositing KInSe 2 (or KIn 1-yGaySe 2) by co-evaporation or KF post-deposition treatment onto CIGS reduces buffer interface recombination in themore » final solar cells. KInSe 2 decomposes in air, which makes characterization difficult and may affect performance. In conclusion, the mechanism for reduced interface recombination could be direct passivation, beneficial compound precursor, oxidation barrier, or favorable diffusion alteration.« less

Review of grain interior, grain boundary, and interface effects of K in CIGS solar cells: Mechanisms for performance enhancement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muzzillo, Christopher P.

Introducing K into Cu(In,Ga)(Se,S) 2 (CIGS) absorbers has led to recent world record power conversion efficiencies for thin film polycrystalline solar cells. In this work, the diverse phenomena associated with K in CIGS were reviewed, and overarching mechanisms were identified. The effects of K depend on its distribution among grain interiors (GIs), grain boundaries (GBs), and interfaces. High substrate Na and low temperature favor GI K incorporation, while low Na and high temperature favor segregation of K at GBs. Depositing KInSe 2 (or KIn 1-yGaySe 2) by co-evaporation or KF post-deposition treatment onto CIGS reduces buffer interface recombination in themore » final solar cells. KInSe 2 decomposes in air, which makes characterization difficult and may affect performance. In conclusion, the mechanism for reduced interface recombination could be direct passivation, beneficial compound precursor, oxidation barrier, or favorable diffusion alteration.« less

Multilayer Transparent Top Electrode for Solution Processed Perovskite/Cu(In,Ga)(Se,S)2 Four Terminal Tandem Solar Cells.

PubMed

Yang, Yang Michael; Chen, Qi; Hsieh, Yao-Tsung; Song, Tze-Bin; Marco, Nicholas De; Zhou, Huanping; Yang, Yang

2015-07-28

Halide perovskites (PVSK) have attracted much attention in recent years due to their high potential as a next generation solar cell material. To further improve perovskites progress toward a state-of-the-art technology, it is desirable to create a tandem structure in which perovskite may be stacked with a current prevailing solar cell such as silicon (Si) or Cu(In,Ga)(Se,S)2 (CIGS). The transparent top electrode is one of the key components as well as challenges to realize such tandem structure. Herein, we develop a multilayer transparent top electrode for perovskite photovoltaic devices delivering an 11.5% efficiency in top illumination mode. The transparent electrode is based on a dielectric/metal/dielectric structure, featuring an ultrathin gold seeded silver layer. A four terminal tandem solar cell employing solution processed CIGS and perovskite cells is also demonstrated with over 15% efficiency.

Quenching Mo optical losses in CIGS solar cells by a point contacted dual-layer dielectric spacer: a 3-D optical study.

PubMed

Rezaei, Nasim; Isabella, Olindo; Vroon, Zeger; Zeman, Miro

2018-01-22

A 3-D optical modelling was calibrated to calculate the light absorption and the total reflection of fabricated CIGS solar cells. Absorption losses at molybdenum (Mo) / CIGS interface were explained in terms of plasmonic waves. To quench these losses, we assumed the insertion of a lossless dielectric spacer between Mo and CIGS, whose optical properties were varied. We show that such a spacer with low refractive index and proper thickness can significantly reduce absorption in Mo in the long wavelength regime and improve the device's rear reflectance, thus leading to enhanced light absorption in the CIGS layer. Therefore, we optimized a realistic two-layer MgF 2 / Al 2 O 3 dielectric spacer to exploit (i) the passivation properties of ultra-thin Al 2 O 3 on the CIGS side for potential high open-circuit voltage and (ii) the low refractive index of MgF 2 on the Mo side to reduce its optical losses. Combining our realistic spacer with optically-optimized point contacts increases the implied photocurrent density of a 750 nm-thick CIGS layer by 10% for the wavelengths between 700 and 1150 nm with respect to the reference cell. The elimination of plasmonic resonances in the new structure leads to a higher electric field magnitude at the bottom of CIGS layer and justifies the improved optical performance.

Proposed suitable electron reflector layer materials for thin-film CuIn1-xGaxSe2 solar cells

NASA Astrophysics Data System (ADS)

Sharbati, Samaneh; Gharibshahian, Iman; Orouji, Ali A.

2018-01-01

This paper investigates the electrical properties of electron reflector layer to survey materials as an electron reflector (ER) for chalcopyrite CuInGaSe solar cells. The purpose is optimizing the conduction-band and valence-band offsets at ER layer/CIGS junction that can effectively reduce the electron recombination near the back contact. In this work, an initial device model based on an experimental solar cell is established, then the properties of a solar cell with electron reflector layer are physically analyzed. The electron reflector layer numerically applied to baseline model of thin-film CIGS cell fabricated by ZSW (efficiency = 20.3%). The improvement of efficiency is achievable by electron reflector layer materials with Eg > 1.3 eV and -0.3 < Δχ < 0.7, depends on bandgap. Our simulations examine various electron reflector layer materials and conclude the most suitable electron reflector layer for this real CIGS solar cells. ZnSnP2, CdSiAs2, GaAs, CdTe, Cu2ZnSnS4, InP, CuO, Pb10Ag3Sb11S28, CuIn5S8, SnS, PbCuSbS3, Cu3AsS4 as well as CuIn1-xGaxSe (x > 0.5) are efficient electron reflector layer materials, so the potential improvement in efficiency obtained relative gain of 5%.

New Materials for Chalcogenide Based Solar Cells

NASA Astrophysics Data System (ADS)

Tosun, Banu Selin

Thin film solar cells based on copper indium gallium diselenide (CIGS) have achieved efficiencies exceeding 20 %. The p-n junction in these solar cells is formed between a p-type CIGS absorber layer and a composite n-type film that consists of a 50-100 nm thin n-type CdS followed by a 50-200 nm thin n-type ZnO. This dissertation focuses on developing materials for replacing CdS and ZnO films to improve the damp-heat stability of the solar cells and for minimizing the use of Cd. Specifically, I demonstrate a new CIGS solar cell with better damp heat stability wherein the ZnO layer is replaced with SnO2. The efficiency of solar cells made with SnO2 decreased less than 5 % after 120 hours at 85 °C and 85 % relative humidity while the efficiency of solar cells made with ZnO declined by more than 70 %. Moreover, I showed that a SnO2 film deposited on top of completed CIGS solar cells significantly increased the device lifetime by forming a barrier against water diffusion. Semicrystalline SnO2 films deposited at room temperature had nanocrystals embedded in an amorphous matrix, which resulted in films without grain boundaries. These films exhibited better damp-heat stability than ZnO and crystalline SnO2 films deposited at higher temperature and this difference is attributed to the lack of grain boundary water diffusion. In addition, I studied CBD of Zn1-xCdxS from aqueous solutions of thiourea, ethylenediaminetetraacetic acid and zinc and cadmium sulfate. I demonstrated that films with varying composition (x) can be deposited through CBD and studied the structure and composition variation along the films' thickness. However, this traditional chemical bath deposition (CBD) approach heats the entire solution and wastes most of the chemicals by homogenous particle formation. To overcome this problem, I designed and developed a continuous-flow CBD approach to utilize the chemicals efficiently and to eliminate homogenous particle formation. Only the substrate is heated to the deposition temperature while the CBD solution is rapidly circulated between the bath and a chilled reservoir. We have demonstrated Zn1-x CdxS films for a variety of (x) values, with and without varying (x) across film thickness.

Effect of thermal annealing on the redistribution of alkali metals in Cu(In,Ga)Se 2 solar cells on glass substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamikawa, Yukiko; Nishinaga, Jiro; Ishizuka, Shogo

The precise control of alkali-metal concentrations in Cu(In,Ga)Se 2 (CIGS) solar cells via post deposition treatment (PDT) has recently attracted attention. When PDT is performed at an elevated temperature, an accompanying annealing effect is expected. Here, we investigate how thermal annealing affects the redistribution of alkali metals in CIGS solar cells on glass substrates and the properties of the solar cells. In addition, we investigate the origin of non-homogeneous alkali-metal depth profiles that are typical of CIGS grown using a three-stage process. In particular, we use secondary-ion mass spectrometry measurements of the ion concentration as a function of distance frommore » the CIGS surface to investigate the impact of thermal annealing on the distribution of alkali metals (Na, Ka, and Rb) and constituent elements (Ga and In) in the CIGS absorbers. We find that the depth profiles of the alkali metals strongly reflect the density of sites that tend to accommodate alkali metals, i.e., vacancies. Annealing at elevated temperature caused a redistribution of the alkali metals. The thermal-diffusion kinetics of alkali metals depends strongly on the species involved. We introduced low flux potassium fluoride (KF) to study a side effect of KF-PDT, i.e., Na removal from CIGS, separately from its predominant effects such as surface modification. When sufficient amounts of Na are supplied from the soda lime glass via annealing at an elevated temperature, the negative effect was not apparent. Conversely, when the Na supply was not sufficient, it caused a deterioration of the photovoltaic properties.« less

Effect of thermal annealing on the redistribution of alkali metals in Cu(In,Ga)Se 2 solar cells on glass substrate

DOE PAGES

Kamikawa, Yukiko; Nishinaga, Jiro; Ishizuka, Shogo; ...

2018-03-07

The precise control of alkali-metal concentrations in Cu(In,Ga)Se 2 (CIGS) solar cells via post deposition treatment (PDT) has recently attracted attention. When PDT is performed at an elevated temperature, an accompanying annealing effect is expected. Here, we investigate how thermal annealing affects the redistribution of alkali metals in CIGS solar cells on glass substrates and the properties of the solar cells. In addition, we investigate the origin of non-homogeneous alkali-metal depth profiles that are typical of CIGS grown using a three-stage process. In particular, we use secondary-ion mass spectrometry measurements of the ion concentration as a function of distance frommore » the CIGS surface to investigate the impact of thermal annealing on the distribution of alkali metals (Na, Ka, and Rb) and constituent elements (Ga and In) in the CIGS absorbers. We find that the depth profiles of the alkali metals strongly reflect the density of sites that tend to accommodate alkali metals, i.e., vacancies. Annealing at elevated temperature caused a redistribution of the alkali metals. The thermal-diffusion kinetics of alkali metals depends strongly on the species involved. We introduced low flux potassium fluoride (KF) to study a side effect of KF-PDT, i.e., Na removal from CIGS, separately from its predominant effects such as surface modification. When sufficient amounts of Na are supplied from the soda lime glass via annealing at an elevated temperature, the negative effect was not apparent. Conversely, when the Na supply was not sufficient, it caused a deterioration of the photovoltaic properties.« less

Experimental studies of thin films deposition by magnetron sputtering method for CIGS solar cell fabrication

NASA Astrophysics Data System (ADS)

Gułkowski, Sławomir; Krawczak, Ewelina

2017-10-01

Among a variety of the thin film solar cell technologies of second generation, copper-indium-gallium-diselenide device (CIGS) with the latest highest lab cell efficiency record of 22.4 % seems to be the most promising for the power generation. This is partly due to the advantages of using low cost films of few microns thick not only as a metallic contacts but also as a main structure of the solar cell consisted of high quality semiconductor layers. This paper reports the experimental studies of the CIGS absorber formation on Soda Lime Glass substrate covered by thin molybdenum film as a back contact layer. All structures were deposited with the use of magnetron sputtering method only. Technological parameters of the deposition process such as deposition power, pressure and deposition time were optimized for each layer of the structure. Mo back contact was examined in terms of resistivity. EDS measurements were carried out to verify stoichiometric composition of CIGS absorber. Thin film of Al was used as a top contact in order to examine the quality of p-n junction. The I-V electrical characteristic of the p-n junction was analysed in terms of solar cell application.

Relationship between open-circuit voltage in Cu(In,Ga)Se2 solar cell and peak position of (220/204) preferred orientation near its absorber surface

NASA Astrophysics Data System (ADS)

Chantana, J.; Watanabe, T.; Teraji, S.; Kawamura, K.; Minemoto, T.

2013-11-01

Cu(In,Ga)Se2 (CIGS) absorbers with various Ga/III, Ga/(In+Ga), profiles are prepared by the so-called "multi-layer precursor method" using multi-layer co-evaporation of material sources. It is revealed that open-circuit voltage (VOC) of CIGS solar cell is primarily dependent on averaged Ga/III near the surface of its absorber. This averaged Ga/III is well predicted by peak position of (220/204) preferred orientation of CIGS film near its surface investigated by glancing-incidence X-ray diffraction with 0.1° incident angle. Finally, the peak position of (220/204) preferred orientation is proposed as a measure of VOC before solar cell fabrication.

Beneficial Effect of Post-Deposition Treatment in High-Efficiency Cu(In,Ga)Se2 Solar Cells through Reduced Potential Fluctuations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jensen, Soren A.; Glynn, Stephen; Kanevce, Ana

World-record power conversion efficiencies for Cu(In,Ga)Se2 (CIGS) solar cells have been achieved via a post-deposition treatment with alkaline metals, which increases the open-circuit voltage and fill factor. We explore the role of the potassium fluoride (KF) post-deposition treatment in CIGS by employing energy- and time-resolved photoluminescence spectroscopy and electrical characterization combined with numerical modeling. The bulk carrier lifetime is found to increase with post-deposition treatment from 255 ns to 388 ns, which is the longest charge carrier lifetime reported for CIGS, and within ~40% of the radiative limit. We find evidence that the post-deposition treatment causes a decrease in themore » electronic potential fluctuations. These potential fluctuations have previously been shown to reduce the open-circuit voltage and the device efficiency in CIGS. Additionally, numerical simulations based on the measured carrier lifetimes and mobilities show a diffusion length of ~10 um, which is ~4 times larger than the film thickness. Thus, carrier collection in the bulk is not a limiting factor for device efficiency. By considering differences in doping, bandgap, and potential fluctuations, we present a possible explanation for the voltage difference between KF-treated and untreated samples.« less

Effect of vacuum thermal annealing on a molybdenum bilayer back contact deposited by radio-frequency magnetron sputtering for chalcogenide- and kesterite-based solar cells

NASA Astrophysics Data System (ADS)

Liu, Xiaolei; Cui, Hongtao; Hao, Xiaojing; Huang, Shujuan; Conibeer, Gavin

2017-12-01

Molybdenum (Mo) thin films are still a dominant choice for the back contact layer of Cu(In,Ga)Se2 (CIGS) and Cu2ZnSnS4 (CZTS) solar cells. This paper presents a review of Mo back contacts for CIGS and CZTS solar cells, including the requirements for a good back contact, the reason for the choice of Mo, and post-treatment. Additionally, a Mo bilayer back contact was fabricated by varying the argon (Ar) pressure during sputtering to provide both low resistivity and good adhesion to the soda-lime glass substrate. The effects of vacuum thermal annealing on the electrical, morphological and structural properties of the Mo bilayer were also investigated. Vacuum thermal annealing was seen to densify the Mo bilayer, reduce the sheet resistance, and improve the bilayer's adhesion to the soda-lime glass. The Mo bilayer back contact with a low sheet resistance of 0.132 Ω/□ and strong adhesion was made for chalcogenide- and kesterite-based solar cells.

Stability of CIGS Solar Cells and Component Materials Evaluated by a Step-Stress Accelerated Degradation Test Method: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pern, F. J.; Noufi, R.

A step-stress accelerated degradation testing (SSADT) method was employed for the first time to evaluate the stability of CuInGaSe2 (CIGS) solar cells and device component materials in four Al-framed test structures encapsulated with an edge sealant and three kinds of backsheet or moisture barrier film for moisture ingress control. The SSADT exposure used a 15oC and then a 15% relative humidity (RH) increment step, beginning from 40oC/40%RH (T/RH = 40/40) to 85oC/70%RH (85/70) as of the moment. The voluminous data acquired and processed as of total DH = 3956 h with 85/70 = 704 h produced the following results. Themore » best CIGS solar cells in sample Set-1 with a moisture-permeable TPT backsheet showed essentially identical I-V degradation trend regardless of the Al-doped ZnO (AZO) layer thickness ranging from standard 0.12 μm to 0.50 μm on the cells. No clear 'stepwise' feature in the I-V parameter degradation curves corresponding to the SSADT T/RH/time profile was observed. Irregularity in I-V performance degradation pattern was observed with some cells showing early degradation at low T/RH < 55/55 and some showing large Voc, FF, and efficiency degradation due to increased series Rs (ohm-cm2) at T/RH ≥ 70/70. Results of (electrochemical) impedance spectroscopy (ECIS) analysis indicate degradation of the CIGS solar cells corresponded to increased series resistance Rs (ohm) and degraded parallel (minority carrier diffusion/recombination) resistance Rp, capacitance C, overall time constant Rp*C, and 'capacitor quality' factor (CPE-P), which were related to the cells? p-n junction properties. Heating at 85/70 appeared to benefit the CIGS solar cells as indicated by the largely recovered CPE-P factor. Device component materials, Mo on soda lime glass (Mo/SLG), bilayer ZnO (BZO), AlNi grid contact, and CdS/CIGS/Mo/SLG in test structures with TPT showed notable to significant degradation at T/RH ≥ 70/70. At T/RH = 85/70, substantial blistering of BZO layers on CIGS cell pieces was observed that was not seen on BZO/glass, and a CdS/CIGS sample displayed a small darkening and then flaking feature. Additionally, standard AlNi grid contact was less stable than thin Ni grid contact at T/RH ≥ 70/70. The edge sealant and moisture-blocking films were effective to block moisture ingress, as evidenced by the good stability of most CIGS solar cells and device components at T/RH = 85/70 for 704 h, and by preservation of the initial blue color on the RH indicator strips. The SSADT experiment is ongoing to be completed at T/RH = 85/85.« less

Alternative buffer layer development in Cu(In,Ga)Se2 thin film solar cells

NASA Astrophysics Data System (ADS)

Xin, Peipei

Cu(In,Ga)Se2-based thin film solar cells are considered to be one of the most promising photovoltaic technologies. Cu(In,Ga)Se2 (CIGS) solar devices have the potential advantage of low-cost, fast fabrication by using semiconductor layers of only a few micrometers thick and high efficiency photovoltaics have been reported at both the cell and the module levels. CdS via chemical bath deposition (CBD) has been the most widely used buffer option to form the critical junction in CIGS-based thin film photovoltaic devices. However, the disadvantages of CdS can’t be ignored - regulations on cadmium usage are getting stricter primarily due to its toxicity and environmental impacts, and the proper handling of the large amount of toxic chemical bath waste is a massive and expensive task. This dissertation is devoted to the development of Cd-free alternative buffer layers in CIGS-based thin film solar cells. Based on the considerations of buffer layer selection criteria and extensive literature review, Zn-compound buffer materials are chosen as the primary investigation candidates. Radio frequency magnetron sputtering is the preferred buffer deposition approach since it’s a clean and more controllable technique compared to CBD, and is readily scaled to large area manufacturing. First, a comprehensive study of the ZnSe1-xOx compound prepared by reactive sputtering was completed. As the oxygen content in the reactive sputtering gas increased, ZnSe1-xOx crystallinity and bandgap decreased. It’s observed that oxygen miscibility in ZnSe was low and a secondary phase formed when the O2 / (O2 + Ar) ratio in the sputtering gas exceeded 2%. Two approaches were proposed to optimize the band alignment between the CIGS and buffer layer. One method focused on the bandgap engineering of the absorber, the other focused on the band structure modification of the buffer. As a result, improved current of the solar cell was achieved although a carrier transport barrier at the junction interface still limited the device performance. Second, an investigation of Zn(S,O) buffer layers was completed. Zn(S,O) films were sputtered in Ar using a ZnO0.7S0.3 compound target. Zn(S,O) films had the composition close to the target with S / (S+O) ratio around 0.3. Zn(S,O) films showed the wurtzite structure with the bandgap about 3.2eV. The champion Cu(In,Ga)Se2 / Zn(S,O) cell had 12.5% efficiency and an (Ag,Cu)(In,Ga)Se2 / Zn(S,O) cell achieved 13.2% efficiency. Detailed device analysis was used to study the Cu(In,Ga)Se2 and (Ag,Cu)(In,Ga)Se2 absorbers, the influence of absorber surface treatments, the effects of device treatments, the sputtering damage and the Na concentration in the absorber. Finally alternative buffer layer development was applied to an innovative superstrate CIGS configuration. The superstrate structure has potential benefits of improved window layer properties, cost reduction, and the possibility to implement back reflector engineering techniques. The application of three buffer layer options - CdS, ZnO and ZnSe was studied and limitations of each were characterized. The best device achieved 8.6% efficiency with a ZnO buffer. GaxOy formation at the junction interface was the main limiting factor of this device performance. For CdS / CIGS and ZnSe / CIGS superstrate devices extensive inter-diffusion between the absorber and buffer layer under CIGS growth conditions was the critical problem. Inter-diffusion severely deteriorated the junction quality and led to poorly behaved devices, despite different efforts to optimize the fabrication process.

Advanced CIGS Photovoltaic Technology: Annual Technical Report--Phase II, 15 November 2002--14 November 2003

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delahoy, A. E.; Chen, L.

2004-05-01

The objective of this subcontract is to develop and integrate the various pieces of new technology that EPV considers enabling for cost-effective production of CIGS modules. EPV has conducted research to help generate a technology base for production of CIGS PV modules using vacuum deposition of CIGS onto glass. This strategy is consistent with the observation that, despite there being several approaches to forming device-quality CIGS, vacuum deposition has maintained the world record for the highest-efficiency CIGS device. A record thin-film solar cell efficiency of 19.2% (with Ni-Al grid and MgF2 ARC) for a 0.41-cm2 device was achieved by NRELmore » in 2003 using vacuum-deposited CIGS. The deposition employed four point sources and detection of the Cu-poor to Cu-rich transition for process control. To extend this type of processing to the realm of large-area substrates, EPV developed vacuum equipment designed for heating and coating 0.43-m2 moving substrates, with a projected further scale up to 0.79 m2. The substrates are typically low-cost, soda-lime glass, and the materials are supplied to the moving substrates using novel linear-source technology developed by EPV. The use of elemental selenium rather than toxic H2Se gas helps make for a safe manufacturing environment. These choices concerning film deposition, substrates, and source materials help to minimize the processing costs of CIGS.« less

Effects of Voltage-Bias Annealing on Metastable Defect Populations in CIGS and CZTSe Solar Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harvey, Steven P.; Johnston, Steve; Teeter, Glenn

2016-11-21

We report on voltage-bias annealing (VBA) experiments performed on CIGS and CZTSe solar cells. In these experiments, completed devices were annealed at moderate temperatures and subsequently quenched with continuously applied voltage bias. These treatments resulted in substantial reversible changes in device characteristics. Photovoltaic (PV) conversion efficiency of the CIGS device varied from below 3% to above 15%, with corresponding changes in CIGS hole density from ~1014 cm-3 to ~1017 cm-3. In the CZTSe device, open-circuit voltage varied from 289 meV to 446 meV, caused by an approximately factor of fifty change in the CZTSe hole density. We interpret these findingsmore » in terms of reversible changes to the metastable point-defect populations that control key properties in these materials. Implications for optimization of PV materials and connections to long-term stability of PV devices are discussed.« less

Relationship between open-circuit voltage in Cu(In,Ga)Se{sub 2} solar cell and peak position of (220/204) preferred orientation near its absorber surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chantana, J., E-mail: jakapan@fc.ritsumei.ac.jp; Minemoto, T.; Watanabe, T.

2013-11-25

Cu(In,Ga)Se{sub 2} (CIGS) absorbers with various Ga/III, Ga/(In+Ga), profiles are prepared by the so-called “multi-layer precursor method” using multi-layer co-evaporation of material sources. It is revealed that open-circuit voltage (V{sub OC}) of CIGS solar cell is primarily dependent on averaged Ga/III near the surface of its absorber. This averaged Ga/III is well predicted by peak position of (220/204) preferred orientation of CIGS film near its surface investigated by glancing-incidence X-ray diffraction with 0.1° incident angle. Finally, the peak position of (220/204) preferred orientation is proposed as a measure of V{sub OC} before solar cell fabrication.

Low-Cd CIGS solar cells made with a hybrid CdS/Zn(O,S) buffer layer

DOE PAGES

Garris, Rebekah L.; Mansfield, Lorelle M.; Egaas, Brian; ...

2016-10-27

In Cu(In,Ga)Se2 (CIGS) solar cells, CdS and Zn(O,S) buffer layers were compared with a hybrid buffer layer consisting of thin CdS followed Zn(O,S). We explore the physics of this hybrid layer that combines the standard (Cd) approach with the alternative (Zn) approach in the pursuit to unlock further potential for CIGS technology. CdS buffer development has shown optimal interface properties, whereas Zn(O,S) buffer development has shown increased photocurrent. Although a totally Cd-free solar module is more marketable, the retention of a small amount of Cd can be beneficial to achieve optimum junction properties. As long as the amount of Cdmore » is reduced to less than 0.01% by weight, the presence of Cd does not violate the hazardous substance restrictions of the European Union (EU). We estimate the amount of Cd allowed in the EU for CIGS on both glass and stainless steel substrates, and we show that reducing Cd becomes increasingly important as substrate weights decrease. As a result, this hybrid buffer layer had reduced Cd content and a wider space charge region, while achieving equal or better solar cell performance than buffer layers of either CdS or Zn(O,S) alone.« less

Controlling Metastable Native Point-Defect Populations in Cu(In,Ga)Se 2 and Cu 2ZnSnSe 4 Materials and Solar Cells through Voltage-Bias Annealing

DOE PAGES

Teeter, Glenn; Harvey, Steve P.; Johnston, Steve

2017-01-30

Our contribution describes the influence of low-temperature annealing with and without applied voltage bias on thin-film Cu 2ZnSnSe 4 (CZTSe), Cu(In,Ga)Se 2 (CIGS), and CdS material properties and solar cell performance. In order to quantify the effects of cation disorder on CZTSe device performance, completed devices were annealed under open-circuit conditions at various temperatures from 110 degrees C to 215 degrees C and subsequently quenched. Measurements on these devices document systematic, reversible changes in solar-cell performance consistent with a reduction in CZTSe band tails at lower annealing temperatures. CIGS and CZTSe solar cells were also annealed at various temperatures (200more » degrees C for CIGS and 110 degrees C-215 degrees C for CZTSe) and subsequently quenched with continuously applied voltage bias to explore the effects of non-equilibrium annealing conditions. For both absorbers, large reversible changes in device characteristics correlated with the magnitude and sign of the applied voltage bias were observed. For CZTSe devices, the voltage-bias annealing (VBA) produced reversible changes in open-circuit voltage (VOC) from 289 meV to 446 meV. For CIGS solar cells, even larger changes were observed in device performance: photovoltaic (PV) conversion efficiency of the CIGS device varied from below 3% to above 15%, with corresponding changes in CIGS hole density of about three orders of magnitude. Findings from these VBA experiments are interpreted in terms of changes to the metastable point-defect populations that control key properties in the absorber layers, and in the CdS buffer layer. Computational device modeling was performed to assess the impacts of cation disorder on the CZTSe VOC deficit, and to elucidate the effects of VBA treatments on metastable point defect populations in CZTSe, CIGS, and CdS. Our results indicate that band tails impose important limitations on CZTSe device performance. Device modeling results also indicate that non-equilibrium processing conditions including the effects of voltage bias can dramatically alter point-defect-mediated opto-electronic properties of semiconductors. Implications for optimization of PV materials and connections to long-term stability of PV devices are discussed.« less

Controlling metastable native point-defect populations in Cu(In,Ga)Se2 and Cu2ZnSnSe4 materials and solar cells through voltage-bias annealing

NASA Astrophysics Data System (ADS)

Teeter, G.; Harvey, S. P.; Johnston, S.

2017-01-01

This contribution describes the influence of low-temperature annealing with and without applied voltage bias on thin-film Cu2ZnSnSe4 (CZTSe), Cu(In,Ga)Se2 (CIGS), and CdS material properties and solar cell performance. To quantify the effects of cation disorder on CZTSe device performance, completed devices were annealed under open-circuit conditions at various temperatures from 110 °C to 215 °C and subsequently quenched. Measurements on these devices document systematic, reversible changes in solar-cell performance consistent with a reduction in CZTSe band tails at lower annealing temperatures. CIGS and CZTSe solar cells were also annealed at various temperatures (200 °C for CIGS and 110 °C-215 °C for CZTSe) and subsequently quenched with continuously applied voltage bias to explore the effects of non-equilibrium annealing conditions. For both absorbers, large reversible changes in device characteristics correlated with the magnitude and sign of the applied voltage bias were observed. For CZTSe devices, the voltage-bias annealing (VBA) produced reversible changes in open-circuit voltage (VOC) from 289 meV to 446 meV. For CIGS solar cells, even larger changes were observed in device performance: photovoltaic (PV) conversion efficiency of the CIGS device varied from below 3% to above 15%, with corresponding changes in CIGS hole density of about three orders of magnitude. Findings from these VBA experiments are interpreted in terms of changes to the metastable point-defect populations that control key properties in the absorber layers, and in the CdS buffer layer. Computational device modeling was performed to assess the impacts of cation disorder on the CZTSe VOC deficit, and to elucidate the effects of VBA treatments on metastable point defect populations in CZTSe, CIGS, and CdS. Results indicate that band tails impose important limitations on CZTSe device performance. Device modeling results also indicate that non-equilibrium processing conditions including the effects of voltage bias can dramatically alter point-defect-mediated opto-electronic properties of semiconductors. Implications for optimization of PV materials and connections to long-term stability of PV devices are discussed.

Controlling Metastable Native Point-Defect Populations in Cu(In,Ga)Se 2 and Cu 2ZnSnSe 4 Materials and Solar Cells through Voltage-Bias Annealing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teeter, Glenn; Harvey, Steve P.; Johnston, Steve

Our contribution describes the influence of low-temperature annealing with and without applied voltage bias on thin-film Cu 2ZnSnSe 4 (CZTSe), Cu(In,Ga)Se 2 (CIGS), and CdS material properties and solar cell performance. In order to quantify the effects of cation disorder on CZTSe device performance, completed devices were annealed under open-circuit conditions at various temperatures from 110 degrees C to 215 degrees C and subsequently quenched. Measurements on these devices document systematic, reversible changes in solar-cell performance consistent with a reduction in CZTSe band tails at lower annealing temperatures. CIGS and CZTSe solar cells were also annealed at various temperatures (200more » degrees C for CIGS and 110 degrees C-215 degrees C for CZTSe) and subsequently quenched with continuously applied voltage bias to explore the effects of non-equilibrium annealing conditions. For both absorbers, large reversible changes in device characteristics correlated with the magnitude and sign of the applied voltage bias were observed. For CZTSe devices, the voltage-bias annealing (VBA) produced reversible changes in open-circuit voltage (VOC) from 289 meV to 446 meV. For CIGS solar cells, even larger changes were observed in device performance: photovoltaic (PV) conversion efficiency of the CIGS device varied from below 3% to above 15%, with corresponding changes in CIGS hole density of about three orders of magnitude. Findings from these VBA experiments are interpreted in terms of changes to the metastable point-defect populations that control key properties in the absorber layers, and in the CdS buffer layer. Computational device modeling was performed to assess the impacts of cation disorder on the CZTSe VOC deficit, and to elucidate the effects of VBA treatments on metastable point defect populations in CZTSe, CIGS, and CdS. Our results indicate that band tails impose important limitations on CZTSe device performance. Device modeling results also indicate that non-equilibrium processing conditions including the effects of voltage bias can dramatically alter point-defect-mediated opto-electronic properties of semiconductors. Implications for optimization of PV materials and connections to long-term stability of PV devices are discussed.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simpson, L.

ITN Energy Systems, Inc., and Global Solar Energy, Inc., with the assistance of NREL's PV Manufacturing R&D program, have continued the advancement of CIGS production technology through the development of trajectory-oriented predictive/control models, fault-tolerance control, control-platform development, in-situ sensors, and process improvements. Modeling activities to date include the development of physics-based and empirical models for CIGS and sputter-deposition processing, implementation of model-based control, and application of predictive models to the construction of new evaporation sources and for control. Model-based control is enabled through implementation of reduced or empirical models into a control platform. Reliability improvement activities include implementation of preventivemore » maintenance schedules; detection of failed sensors/equipment and reconfiguration to continue processing; and systematic development of fault prevention and reconfiguration strategies for the full range of CIGS PV production deposition processes. In-situ sensor development activities have resulted in improved control and indicated the potential for enhanced process status monitoring and control of the deposition processes. Substantial process improvements have been made, including significant improvement in CIGS uniformity, thickness control, efficiency, yield, and throughput. In large measure, these gains have been driven by process optimization, which, in turn, have been enabled by control and reliability improvements due to this PV Manufacturing R&D program. This has resulted in substantial improvements of flexible CIGS PV module performance and efficiency.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simpson, L.; Britt, J.; Birkmire, R.

ITN Energy Systems, Inc., and Global Solar Energy, Inc., assisted by NREL's PV Manufacturing R&D program, have continued to advance CIGS production technology by developing trajectory-oriented predictive/control models, fault-tolerance control, control platform development, in-situ sensors, and process improvements. Modeling activities included developing physics-based and empirical models for CIGS and sputter-deposition processing, implementing model-based control, and applying predictive models to the construction of new evaporation sources and for control. Model-based control is enabled by implementing reduced or empirical models into a control platform. Reliability improvement activities include implementing preventive maintenance schedules; detecting failed sensors/equipment and reconfiguring to tinue processing; and systematicmore » development of fault prevention and reconfiguration strategies for the full range of CIGS PV production deposition processes. In-situ sensor development activities have resulted in improved control and indicated the potential for enhanced process status monitoring and control of the deposition processes. Substantial process improvements have been made, including significant improvement in CIGS uniformity, thickness control, efficiency, yield, and throughput. In large measure, these gains have been driven by process optimization, which in turn have been enabled by control and reliability improvements due to this PV Manufacturing R&D program.« less

Optimization of Post-selenization Process of Co-sputtered CuIn and CuGa Precursor for 11.19% Efficiency Cu(In, Ga)Se2 Solar Cells

NASA Astrophysics Data System (ADS)

Cheng, Ke; Han, Kaikai; Kuang, Zhongcheng; Jin, Ranran; Hu, Junxia; Guo, Longfei; Liu, Ya; Lu, Zhangbo; Du, Zuliang

2017-04-01

In this work, CuInGa alloy precursor films are fabricated by co-sputtering of CuIn and CuGa targets simultaneously. After selenization in a tube-type rapid thermal annealing system under a Se atmosphere, the Cu(In, Ga)Se2 (CIGS) absorber layers are obtained. Standard soda lime glass (SLG)/Mo/CIGS/CdS/i-ZnO/ITO/Ag grid structural solar cells are fabricated based on the selenized CIGS absorbers. The influences of selenization temperatures on the composition, crystallinity, and device performances are systematically investigated by x-ray energy dispersive spectroscopy, x-ray diffraction, Raman spectroscopy, and the current density-voltage ( J- V) measurement. It is found that the elemental ratio of Cu/(In + Ga) strongly depends on the selenization temperatures. Because of the appropriate elemental ratio, a 9.92% conversion efficiency is reached for the CIGS absorber selenized at 560°C. After the additional optimization by pre-annealing treatment at 280°C before the selenization, a highest conversion efficiency of 11.19% with a open-circuit ( V oc) of 456 mV, a short-circuit ( J sc) of 40.357 mA/cm2 and a fill factor of 60.82% without antireflection coating has been achieved. Above 13% efficiency improvement was achievable. Our experimental findings presented in this work demonstrate that the post-selenization of co-sputtered CuIn and CuGa precursor is a promising way to fabricate high quality CIGS absorbers.

Nanosecond laser scribing of CIGS thin film solar cell based on ITO bottom contact

NASA Astrophysics Data System (ADS)

Kuk, Seungkuk; Wang, Zhen; Fu, Shi; Zhang, Tao; Yu, Yi Yin; Choi, JaeMyung; Jeong, Jeung-hyun; Hwang, David J.

2018-03-01

Cu(In,Ga)Se2 (CIGS) thin films, a promising photovoltaic architecture, have mainly relied on Molybdenum for the bottom contact. However, the opaque nature of Molybdenum (Mo) poses limitations in module level fabrication by laser scribing as a preferred method for interconnect. We examined the P1, P2, and P3 laser scribing processes on CIGS photovoltaic architecture on the indium tin oxide (ITO) bottom contact with a cost-effective nanosecond pulsed laser of 532 nm wavelength. Laser illuminated from the substrate side, enabled by the transparent bottom contact, facilitated selective laser energy deposition onto relevant interfaces towards high-quality scribing. Parametric tuning procedures are described in conjunction with experimental and numerical investigation of relevant mechanisms, and preliminary mini-module fabrication results are also presented.

Beneficial effect of post-deposition treatment in high-efficiency Cu(In,Ga)Se{sub 2} solar cells through reduced potential fluctuations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jensen, S. A., E-mail: Soren.Jensen@nrel.gov, E-mail: Darius.Kuciauskas@nrel.gov; Glynn, S.; Kanevce, A.

World-record power conversion efficiencies for Cu(In,Ga)Se{sub 2} (CIGS) solar cells have been achieved via a post-deposition treatment with alkaline metals, which increases the open-circuit voltage and fill factor. We explore the role of the potassium fluoride (KF) post-deposition treatment in CIGS by employing energy- and time-resolved photoluminescence spectroscopy and electrical characterization combined with numerical modeling. The bulk carrier lifetime is found to increase with post-deposition treatment from 255 ns to 388 ns, which is the longest charge carrier lifetime reported for CIGS, and within ∼40% of the radiative limit. We find evidence that the post-deposition treatment causes a decrease in the electronicmore » potential fluctuations. These potential fluctuations have previously been shown to reduce the open-circuit voltage and the device efficiency in CIGS. Additionally, numerical simulations based on the measured carrier lifetimes and mobilities show a diffusion length of ∼10 μm, which is ∼4 times larger than the film thickness. Thus, carrier collection in the bulk is not a limiting factor for device efficiency. By considering differences in doping, bandgap, and potential fluctuations, we present a possible explanation for the voltage difference between KF-treated and untreated samples.« less

How Does CIGS Performance Depend on Temperature at the Microscale?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stuckelberger, Michael E.; Nietzold, Tara; West, Bradley M.

Unveiling the correlation among electrical performance, elemental distribution, and defects at the microscale is crucial for the understanding and improvement of the overall solar cell performance. While this is true in general for solar cells with polycrystalline absorber layers, it is particularly critical for defect engineering of the complex quaternary CuIn xGa 1-xSe 2 (CIGS) material system. Studying these relationships under standard ambient conditions can provide important insights but does not provide input on the behavior of the cell under real operating conditions. In this contribution, we take a close look at the complex temperature dependence of defects and voltagemore » in CIGS at the microscale. We have developed correlative X-raymicroscopymethods and adapted them for temperature-dependent measurements of the locally generated voltage and elemental compositions at the microscale. We have applied these techniques to industrial CIGS solar cells covering temperatures from room temperature up to 100 degrees C. Finally, we find underperforming areas spanning multiple grains that do not correlate with the elemental distribution of major absorber constituents. However, we demonstrate that low-performing areas perform better at higher temperatures relative to the high-performing areas.« less

Improved efficiency of a large-area Cu(In,Ga)Se₂ solar cell by a nontoxic hydrogen-assisted solid Se vapor selenization process.

PubMed

Wu, Tsung-Ta; Hu, Fan; Huang, Jyun-Hong; Chang, Chia-ho; Lai, Chih-chung; Yen, Yu-Ting; Huang, Hou-Ying; Hong, Hwen-Fen; Wang, Zhiming M; Shen, Chang-Hong; Shieh, Jia-Min; Chueh, Yu-Lun

2014-04-09

A nontoxic hydrogen-assisted solid Se vapor selenization process (HASVS) technique to achieve a large-area (40 × 30 cm(2)) Cu(In,Ga)Se2 (CIGS) solar panel with enhanced efficiencies from 7.1 to 10.8% (12.0% for active area) was demonstrated. The remarkable improvement of efficiency and fill factor comes from improved open circuit voltage (Voc) and reduced dark current due to (1) decreased interface recombination raised from the formation of a widened buried homojunction with n-type Cd(Cu) participation and (2) enhanced separation of electron and hole carriers resulting from the accumulation of Na atoms on the surface of the CIGS film. The effects of microstructural, compositional, and electrical characteristics with hydrogen-assisted Se vapor selenization, including interdiffusion of atoms and formation of buried homojunction, were examined in detail. This methodology can be also applied to CIS (CuInSe2) thin film solar cells with enhanced efficiencies from 5.3% to 8.5% (9.4% for active area) and provides a facile approach to improve quality of CIGS and stimulate the nontoxic progress in the large scale CIGS PV industry.

How Does CIGS Performance Depend on Temperature at the Microscale?

DOE PAGES

Stuckelberger, Michael E.; Nietzold, Tara; West, Bradley M.; ...

2017-11-03

Unveiling the correlation among electrical performance, elemental distribution, and defects at the microscale is crucial for the understanding and improvement of the overall solar cell performance. While this is true in general for solar cells with polycrystalline absorber layers, it is particularly critical for defect engineering of the complex quaternary CuIn xGa 1-xSe 2 (CIGS) material system. Studying these relationships under standard ambient conditions can provide important insights but does not provide input on the behavior of the cell under real operating conditions. In this contribution, we take a close look at the complex temperature dependence of defects and voltagemore » in CIGS at the microscale. We have developed correlative X-raymicroscopymethods and adapted them for temperature-dependent measurements of the locally generated voltage and elemental compositions at the microscale. We have applied these techniques to industrial CIGS solar cells covering temperatures from room temperature up to 100 degrees C. Finally, we find underperforming areas spanning multiple grains that do not correlate with the elemental distribution of major absorber constituents. However, we demonstrate that low-performing areas perform better at higher temperatures relative to the high-performing areas.« less

Detection of Matrix Elements and Trace Impurities in Cu(In, Ga)Se2 Photovoltaic Absorbers Using Surface Analytical Techniques.

PubMed

Kim, Min Jung; Lee, Jihye; Kim, Seon Hee; Kim, Haidong; Lee, Kang-Bong; Lee, Yeonhee

2015-10-01

Chalcopyrite Cu(In, Ga)Se2 (CIGS) thin films are well known as the next-generation solar cell materials notable for their high absorption coefficient for solar radiation, suitable band gap, and ability for deposition on flexible substrate materials, allowing the production of highly flexible and lightweight solar panels. To improve solar cell performances, a quantitative and depth-resolved elemental analysis of photovoltaic thin films is much needed. In this study, Cu(In, Ga)Se2 thin films were prepared on molybdenum back contacts deposited on soda-lime glass substrates via three-stage evaporation. Surface analyses via AES and SIMS were used to characterize the CIGS thin films and compare their depth profiles. We determined the average concentration of the matrix elements, Cu, In, Ga, and Se, using ICP-AES, XRF, and EPMA. We also obtained depth profiling results using TOF-SIMS, magnetic sector SIMS and AES, and APT, a sub-nanometer resolution characterization technique that enables three-dimensional elemental mapping. The SIMS technique, with its high detection limit and ability to obtain the profiles of elements in parallel, is a powerful tool for monitoring trace elements in CIGS thin films. To identify impurities in a CIGS layer, the distribution of trace elements was also observed according to depth by SIMS and APT.

Semi-transparent perovskite solar cells for tandems with silicon and CIGS

DOE PAGES

Bailie, Colin D.; Christoforo, M. Greyson; Mailoa, Jonathan P.; ...

2014-12-23

A promising approach for upgrading the performance of an established low-bandgap solar technology without adding much cost is to deposit a high bandgap polycrystalline semiconductor on top to make a tandem solar cell. We use a transparent silver nanowire electrode on perovskite solar cells to achieve a semi-transparent device. We place the semi-transparent cell in a mechanically-stacked tandem configuration onto copper indium gallium diselenide (CIGS) and low-quality multicrystalline silicon (Si) to achieve solid-state polycrystalline tandem solar cells with a net improvement in efficiency over the bottom cell alone. Furthermore, this work paves the way for integrating perovskites into a low-costmore » and high-efficiency (>25%) tandem cell.« less

19.5%-Efficient CuIn1-xGaxSe2 Photovoltaic Cells Using A Cd-Zn-S Buffer Layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharya. R. N.

2008-01-01

CuIn1-xGaxSe2 (CIGS) solar cell junctions prepared by chemical-bath-deposited (CBD) Zn1-xCdxS (CdZnS), ZnS, and CdS buffer layers are discussed. A 19.52%-efficient, CIGS-based, thin-film photovoltaic device has been fabricated using a single-layer CBD CdZnS buffer layer. The mechanism that creates extensive hydroxide and oxide impurities in CBD-ZnS and CBD-CdZnS thin films (compared to CBD-CdS thin film) is presented.

Development of coring procedures applied to Si, CdTe, and CIGS solar panels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moutinho, H. R.; Johnston, S.; To, B.

Most of the research on the performance and degradation of photovoltaic modules is based on macroscale measurements of device parameters such as efficiency, fill factor, open-circuit voltage, and short-circuit current. Our goal is to develop the capabilities to allow us to study the degradation of these parameters in the micro- and nanometer scale and to relate our results to performance parameters. To achieve this objective, the first step is to be able to access small samples from specific areas of the solar panels without changing the properties of the material. In this paper, we describe two coring procedures that wemore » developed and applied to Si, CIGS, and CdTe solar panels. In the first procedure, we cored full samples, whereas in the second we performed a partial coring that keeps the tempered glass intact. The cored samples were analyzed by different analytical techniques before and after coring, at the same locations, and no damage during the coring procedure was observed.« less

Development of coring procedures applied to Si, CdTe, and CIGS solar panels

DOE PAGES

Moutinho, H. R.; Johnston, S.; To, B.; ...

2018-01-04

Most of the research on the performance and degradation of photovoltaic modules is based on macroscale measurements of device parameters such as efficiency, fill factor, open-circuit voltage, and short-circuit current. Our goal is to develop the capabilities to allow us to study the degradation of these parameters in the micro- and nanometer scale and to relate our results to performance parameters. To achieve this objective, the first step is to be able to access small samples from specific areas of the solar panels without changing the properties of the material. In this paper, we describe two coring procedures that wemore » developed and applied to Si, CIGS, and CdTe solar panels. In the first procedure, we cored full samples, whereas in the second we performed a partial coring that keeps the tempered glass intact. The cored samples were analyzed by different analytical techniques before and after coring, at the same locations, and no damage during the coring procedure was observed.« less

Growth and characterization of CdS buffer layers by CBD and MOCVD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morrone, A.A.; Huang, C.; Li, S.S.

1999-03-01

Thin film CdS has been widely used in thin-film photovoltaic devices. The most efficient Cu(In,&hthinsp;Ga)Se{sub 2} (CIGS) solar cells reported to date utilized a thin CdS buffer layer prepared by a reactive solution growth technique known as chemical bath deposition (CBD). Considerable effort has been directed to better understand the role and find a replacement for the CBD CdS process in CIGS-based solar cells. We reported a low temperature ({approximately}150&hthinsp;{degree}C) Metalorganic Chemical Vapor Deposition (MOCVD) CdS thin film buffer layer process for CIGS absorbers. Many prior studies have reported that CBD CdS contains a mixture of crystal structures. Recent investigationsmore » of CBD CdS thin films by ellipsometry suggested a multilayer structure. In this study we compare CdS thin films prepared by CBD and MOCVD and the effects of annealing. TED and XRD are used to characterize the crystal structure, the film microstructure is studied by HRTEM, and the optical properties are studied by Raman and spectrophotometry. All of these characterization techniques reveal superior crystalline film quality for CdS films grown by MOCVD compared to those grown by CBD. Dual Beam Optical Modulation (DBOM) studies showed that the MOCVD and CBD CdS buffer layer processes have nearly the same effect on CIGS absorbers when combined with a cadmium partial electrolyte aqueous dip. {copyright} {ital 1999 American Institute of Physics.}« less

Self-assembled synthesis of 3D Cu(In1 - xGax)Se2 nanoarrays by one-step electroless deposition into ordered AAO template

NASA Astrophysics Data System (ADS)

Zhang, Bin; Zhou, Tao; Zheng, Maojun; Xiong, Zuzhou; Zhu, Changqing; Li, Hong; Wang, Faze; Ma, Li; Shen, Wenzhong

2014-07-01

Quaternary nanostructured Cu(In1 - xGax)Se2 (CIGS) arrays were successfully fabricated via a novel and simple solution-based protocol on the electroless deposition method, using a flexible, highly ordered anodic aluminium oxide (AAO) substrate. This method does not require electric power, complicated sensitization processes, or complexing agents, but provides nearly 100% pore fill factor to AAO templates. The field emission scanning electron microscopy (FE-SEM) images show that we obtained uniformly three-dimensional nanostructured CIGS arrays, and we can tailor the diameter and wall thicknesses of the nanostructure by adjusting the pore diameter of the AAO and metal Mo layer. Their chemical composition was determined by energy-dispersive spectroscopy analysis, which is very close to the stoichiometric value. The Raman spectroscopy, x-ray diffraction (XRD) pattern, and transmission electron microscopy (TEM) further confirm the formation of nanostructured CIGS with prominent chalcopyrite structure. The nanostructured CIGS arrays can support the design of low-cost, highlight-trapping, and enhanced carrier collection nanostructured solar cells.

Ecotoxicological assessment of solar cell leachates: Copper indium gallium selenide (CIGS) cells show higher activity than organic photovoltaic (OPV) cells.

PubMed

Brun, Nadja Rebecca; Wehrli, Bernhard; Fent, Karl

2016-02-01

Despite the increasing use of photovoltaics their potential environmental risks are poorly understood. Here, we compared ecotoxicological effects of two thin-film photovoltaics: established copper indium gallium selenide (CIGS) and organic photovoltaic (OPV) cells. Leachates were produced by exposing photovoltaics to UV light, physical damage, and exposure to environmentally relevant model waters, representing mesotrophic lake water, acidic rain, and seawater. CIGS cell leachates contained 583 μg L(-1) molybdenum at lake water, whereas at acidic rain and seawater conditions, iron, copper, zinc, molybdenum, cadmium, silver, and tin were present up to 7219 μg L(-1). From OPV, copper (14 μg L(-1)), zinc (87 μg L(-1)) and silver (78 μg L(-1)) leached. Zebrafish embryos were exposed until 120 h post-fertilization to these extracts. CIGS leachates produced under acidic rain, as well as CIGS and OPV leachates produced under seawater conditions resulted in a marked hatching delay and increase in heart edema. Depending on model water and solar cell, transcriptional alterations occurred in genes involved in oxidative stress (cat), hormonal activity (vtg1, ar), metallothionein (mt2), ER stress (bip, chop), and apoptosis (casp9). The effects were dependent on the concentrations of cationic metals in leachates. Addition of ethylenediaminetetraacetic acid protected zebrafish embryos from morphological and molecular effects. Our study suggests that metals leaching from damaged CIGS cells, may pose a potential environmental risk. Copyright © 2015 Elsevier B.V. All rights reserved.

Potassium-induced surface modification of Cu(In,Ga)Se2 thin films for high-efficiency solar cells.

PubMed

Chirilă, Adrian; Reinhard, Patrick; Pianezzi, Fabian; Bloesch, Patrick; Uhl, Alexander R; Fella, Carolin; Kranz, Lukas; Keller, Debora; Gretener, Christina; Hagendorfer, Harald; Jaeger, Dominik; Erni, Rolf; Nishiwaki, Shiro; Buecheler, Stephan; Tiwari, Ayodhya N

2013-12-01

Thin-film photovoltaic devices based on chalcopyrite Cu(In,Ga)Se2 (CIGS) absorber layers show excellent light-to-power conversion efficiencies exceeding 20%. This high performance level requires a small amount of alkaline metals incorporated into the CIGS layer, naturally provided by soda lime glass substrates used for processing of champion devices. The use of flexible substrates requires distinct incorporation of the alkaline metals, and so far mainly Na was believed to be the most favourable element, whereas other alkaline metals have resulted in significantly inferior device performance. Here we present a new sequential post-deposition treatment of the CIGS layer with sodium and potassium fluoride that enables fabrication of flexible photovoltaic devices with a remarkable conversion efficiency due to modified interface properties and mitigation of optical losses in the CdS buffer layer. The described treatment leads to a significant depletion of Cu and Ga concentrations in the CIGS near-surface region and enables a significant thickness reduction of the CdS buffer layer without the commonly observed losses in photovoltaic parameters. Ion exchange processes, well known in other research areas, are proposed as underlying mechanisms responsible for the changes in chemical composition of the deposited CIGS layer and interface properties of the heterojunction.

Complementary Characterization of Cu(In,Ga)Se₂ Thin-Film Photovoltaic Cells Using Secondary Ion Mass Spectrometry, Auger Electron Spectroscopy, and Atom Probe Tomography.

PubMed

Jang, Yun Jung; Lee, Jihye; Jeong, Jeung-Hyun; Lee, Kang-Bong; Kim, Donghwan; Lee, Yeonhee

2018-05-01

To enhance the conversion performance of solar cells, a quantitative and depth-resolved elemental analysis of photovoltaic thin films is required. In this study, we determined the average concentration of the major elements (Cu, In, Ga, and Se) in fabricated Cu(In,Ga)Se2 (CIGS) thin films, using inductively coupled plasma atomic emission spectroscopy, X-ray fluorescence, and wavelengthdispersive electron probe microanalysis. Depth profiling results for CIGS thin films with different cell efficiencies were obtained using secondary ion mass spectrometry and Auger electron spectroscopy to compare the atomic concentrations. Atom probe tomography, a characterization technique with sub-nanometer resolution, was used to obtain three-dimensional elemental mapping and the compositional distribution at the grain boundaries (GBs). GBs are identified by Na increment accompanied by Cu depletion and In enrichment. Segregation of Na atoms along the GB had a beneficial effect on cell performance. Comparative analyses of different CIGS absorber layers using various analytical techniques provide us with understanding of the compositional distributions and structures of high efficiency CIGS thin films in solar cells.

Systems and methods for solar cells with CIS and CIGS films made by reacting evaporated copper chlorides with selenium

DOEpatents

Albin, David S.; Noufi, Rommel

2015-06-09

Systems and methods for solar cells with CIS and CIGS films made by reacting evaporated copper chlorides with selenium are provided. In one embodiment, a method for fabricating a thin film device comprises: providing a semiconductor film comprising indium (In) and selenium (Se) upon a substrate; heating the substrate and the semiconductor film to a desired temperature; and performing a mass transport through vapor transport of a copper chloride vapor and se vapor to the semiconductor film within a reaction chamber.

Understanding the cell-to-module efficiency gap in Cu(In,Ga)(S,Se)2 photovoltaics scale-up

NASA Astrophysics Data System (ADS)

Bermudez, Veronica; Perez-Rodriguez, Alejandro

2018-06-01

Cu(In,Ga)(S,Se)2 (CIGS) solar cells show record efficiencies comparable to those of crystalline Si-based technologies. Their industrial module production costs are also comparable to those of Si photovoltaics in spite of their much lower production volume. However, the competitiveness of CIGS is compromised by the difference in performance between cell and module scales, known as the cell-to-module efficiency gap, which is significantly higher than in competing industrial photovoltaic technologies. In this Review, we quantify the main cell-to-module efficiency loss mechanisms and discuss the various strategies explored in academia and industry to reduce the efficiency gap: new transparent conductive oxides, hybrid modularization approaches and the use of wide-bandgap solar absorbers in the 1.4-1.5 eV range. To implement these strategies, research gaps relating to various device layers need to be filled.

Rubidium distribution at atomic scale in high efficient Cu(In,Ga)Se2 thin-film solar cells

NASA Astrophysics Data System (ADS)

Vilalta-Clemente, Arantxa; Raghuwanshi, Mohit; Duguay, Sébastien; Castro, Celia; Cadel, Emmanuel; Pareige, Philippe; Jackson, Philip; Wuerz, Roland; Hariskos, Dimitrios; Witte, Wolfram

2018-03-01

The introduction of a rubidium fluoride post deposition treatment (RbF-PDT) for Cu(In,Ga)Se2 (CIGS) absorber layers has led to a record efficiency up to 22.6% for thin-film solar cell technology. In the present work, high efficiency CIGS samples with RbF-PDT have been investigated by atom probe tomography (APT) to reveal the atomic distribution of all alkali elements present in CIGS layers and compared with non-treated samples. A Scanning Electron Microscopy Dual beam station (Focused Ion Beam-Gas Injection System) as well as Transmission Kikuchi diffraction is used for atom probe sample preparation and localization of the grain boundaries (GBs) in the area of interest. The analysis of the 3D atomic scale APT reconstructions of CIGS samples with RbF-PDT shows that inside grains, Rb is under the detection limit, but the Na concentration is enhanced as compared to the reference sample without Rb. At the GBs, a high concentration of Rb reaching 1.5 at. % was found, and Na and K (diffusing from the glass substrate) are also segregated at GBs but at lower concentrations as compared to Rb. The intentional introduction of Rb leads to significant changes in the chemical composition of CIGS matrix and at GBs, which might contribute to improve device efficiency.

Point contacts at the copper-indium-gallium-selenide interface—A theoretical outlook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bercegol, Adrien, E-mail: adrien.bercegol@polytechnique.edu; Chacko, Binoy; Klenk, Reiner

For a long time, it has been assumed that recombination in the space-charge region of copper-indium-gallium-selenide (CIGS) is dominant, at least in high efficiency solar cells with low band gap. The recent developments like potassium fluoride post deposition treatment and point-contact junction may call this into question. In this work, a theoretical outlook is made using three-dimensional simulations to investigate the effect of point-contact openings through a passivation layer on CIGS solar cell performance. A large set of solar cells is modeled under different scenarios for the charged defect levels and density, radius of the openings, interface quality, and conductionmore » band offset. The positive surface charge created by the passivation layer induces band bending and this influences the contact (CdS) properties, making it beneficial for the open circuit voltage and efficiency, and the effect is even more pronounced when coverage area is more than 95%, and also makes a positive impact on the device performance, even in the presence of a spike at CIGS/CdS heterojunction.« less

Amorphous oxides as electron transport layers in Cu(In,Ga)Se 2 superstrate devices: Amorphous oxides in Cu(In,Ga)Se 2 superstrate devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heinemann, M. D.; van Hest, M. F. A. M.; Contreras, M.

Cu(In,Ga)Se2 (CIGS) solar cells in superstrate configuration promise improved light management and higher stability compared to substrate devices, but they have yet to deliver comparable power conversion efficiencies (PCEs). Chemical reactions between the CIGS layer and the front contact were shown in the past to deteriorate the p-n junction in superstrate devices, which led to lower efficiencies compared to the substrate-type devices. This work aims to solve this problem by identifying a buffer layer between the CIGS layer and the front contact, acting as the electron transport layer, with an optimized electron affinity, doping density and chemical stability. Using combinatorialmore » material exploration we identified amorphous gallium oxide (a-GaOx) as a potentially suitable buffer layer material. The best results were obtained for a-GaOx with an electron affinity that was found to be comparable to that of CIGS. Based on the results of device simulations, it is assumed that detrimental interfacial acceptor states are present at the interface between CIGS and a-GaOx. However, these initial experiments indicate the potential of a-GaOx in this application, and how to reach performance parity with substrate devices, by further increase of its n-type doping density.« less

Design and Optimization of Copper Indium Gallium Selenide Solar Cells for Lightweight Battlefield Application

DTIC Science & Technology

2014-06-01

spectrum. This results in most of the incident sunlight being absorbed close to the p-n hetero - junction formed with the CdS layer. This property is what... junction layer in the solar cell hetero - junction . A thin layer of CdS is used in CIGS cells to accomplish this. CdS has a band gap of 2.4 eV, which...field between the p-n hetero - junction at the cost of absorbing more of the usable photons from reaching the CIGS layer. From Figure 28, CdS reached peak

Thin Film CIGS and CdTe Photovoltaic Technologies: Commercialization, Critical Issues, and Applications; Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ullal, H. S.; von Roedern, B.

2007-09-01

We report here on the major commercialization aspects of thin-film photovoltaic (PV) technologies based on CIGS and CdTe (a-Si and thin-Si are also reported for completeness on the status of thin-film PV). Worldwide silicon (Si) based PV technologies continues to dominate at more than 94% of the market share, with the share of thin-film PV at less than 6%. However, the market share for thin-film PV in the United States continues to grow rapidly over the past several years and in CY 2006, they had a substantial contribution of about 44%, compared to less than 10% in CY 2003. Inmore » CY 2007, thin-film PV market share is expected to surpass that of Si technology in the United States. Worldwide estimated projections for CY 2010 are that thin-film PV production capacity will be more than 3700 MW. A 40-MW thin-film CdTe solar field is currently being installed in Saxony, Germany, and will be completed in early CY 2009. The total project cost is Euro 130 million, which equates to an installed PV system price of Euro 3.25/-watt averaged over the entire solar project. This is the lowest price for any installed PV system in the world today. Critical research, development, and technology issues for thin-film CIGS and CdTe are also elucidated in this paper.« less

ZnS/Zn(O,OH)S-based buffer layer deposition for solar cells

DOEpatents

Bhattacharya, Raghu N [Littleton, CO

2009-11-03

The invention provides CBD ZnS/Zn(O,OH)S and spray deposited ZnS/Zn(O,OH)S buffer layers prepared from a solution of zinc salt, thiourea and ammonium hydroxide dissolved in a non-aqueous/aqueous solvent mixture or in 100% non-aqueous solvent. Non-aqueous solvents useful in the invention include methanol, isopropanol and triethyl-amine. One-step deposition procedures are described for CIS, CIGS and other solar cell devices.

A comparative study on charge carrier recombination across the junction region of Cu{sub 2}ZnSn(S,Se){sub 4} and Cu(In,Ga)Se{sub 2} thin film solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halim, Mohammad Abdul, E-mail: halimtsukuba2012@gmail.com; Islam, Muhammad Monirul; Luo, Xianjia

A comparative study with focusing on carrier recombination properties in Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) and the CuInGaSe{sub 2} (CIGS) solar cells has been carried out. For this purpose, electroluminescence (EL) and also bias-dependent time resolved photoluminescence (TRPL) using femtosecond (fs) laser source were performed. For the similar forward current density, the EL-intensity of the CZTSSe sample was obtained significantly lower than that of the CIGS sample. Primarily, it can be attributed to the existence of excess amount of non-radiative recombination center in the CZTSSe, and/or CZTSSe/CdS interface comparing to that of CIGS sample. In case of CIGS sample, TRPL decaymore » time was found to increase with the application of forward-bias. This can be attributed to the reduced charge separation rate resulting from the reduced electric-field at the junction. However, in CZTSSe sample, TRPL decay time has been found almost independent under the forward and reverse-bias conditions. This phenomenon indicates that the charge recombination rate strongly dominates over the charge separation rate across the junction of the CZTSSe sample. Finally, temperature dependent V{sub OC} suggests that interface related recombination in the CZTSSe solar cell structure might be one of the major factors that affect EL-intensity and also, TRPL decay curves.« less

Research | Photovoltaic Research | NREL

Science.gov Websites

-V cells Hybrid tandems Polycrystalline Thin-Film PV CdTe solar cells CIGS solar cells Perovskites and Organic PV Perovskite solar cells Organic PV solar cells Advanced Materials, Devices, and Science Interfacial and Surface Science Reliability and Engineering Real-Time PV and Solar Resource

Locating the electrical junctions in Cu(In,Ga)Se 2 and Cu 2ZnSnSe 4 solar cells by scanning capacitance spectroscopy

DOE PAGES

Xiao, Chuanxiao; Jiang, Chun -Sheng; Moutinho, Helio; ...

2016-08-09

Here, we determined the electrical junction (EJ) locations in Cu(In,Ga)Se 2 (CIGS) and Cu 2ZnSnSe 4 (CZTS) solar cells with ~20-nm accuracy by developing scanning capacitance spectroscopy (SCS) applicable to the thin-film devices. Cross-sectional sample preparation for the SCS measurement was developed by high-energy ion milling at room temperature for polishing the cross section to make it flat, followed by low-energy ion milling at liquid nitrogen temperature for removing the damaged layer and subsequent annealing for growing a native oxide layer. The SCS shows distinct p-type, transitional, and n-type spectra across the devices, and the spectral features change rapidly withmore » location in the depletion region, which results in determining the EJ with ~20-nm resolution. We found an n-type CIGS in the region next to the CIGS/CdS interface; thus, the cell is a homojunction. The EJ is ~40 nm from the interface on the CIGS side. In contrast, such an n-type CZTS was not found in the CZTS/CdS cells. The EJ is ~20 nm from the CZTS/CdS interface, which is consistent with asymmetrical carrier concentrations of the p-CZTS and n-CdS in a heterojunction cell. Our results of unambiguously determination of the junction locations contribute significantly to understanding the large open-circuit voltage difference between CIGS and CZTS.« less

Locating the electrical junctions in Cu(In,Ga)Se 2 and Cu 2ZnSnSe 4 solar cells by scanning capacitance spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Chuanxiao; Jiang, Chun -Sheng; Moutinho, Helio

Here, we determined the electrical junction (EJ) locations in Cu(In,Ga)Se 2 (CIGS) and Cu 2ZnSnSe 4 (CZTS) solar cells with ~20-nm accuracy by developing scanning capacitance spectroscopy (SCS) applicable to the thin-film devices. Cross-sectional sample preparation for the SCS measurement was developed by high-energy ion milling at room temperature for polishing the cross section to make it flat, followed by low-energy ion milling at liquid nitrogen temperature for removing the damaged layer and subsequent annealing for growing a native oxide layer. The SCS shows distinct p-type, transitional, and n-type spectra across the devices, and the spectral features change rapidly withmore » location in the depletion region, which results in determining the EJ with ~20-nm resolution. We found an n-type CIGS in the region next to the CIGS/CdS interface; thus, the cell is a homojunction. The EJ is ~40 nm from the interface on the CIGS side. In contrast, such an n-type CZTS was not found in the CZTS/CdS cells. The EJ is ~20 nm from the CZTS/CdS interface, which is consistent with asymmetrical carrier concentrations of the p-CZTS and n-CdS in a heterojunction cell. Our results of unambiguously determination of the junction locations contribute significantly to understanding the large open-circuit voltage difference between CIGS and CZTS.« less

Reducing interface recombination for Cu(In,Ga)Se{sub 2} by atomic layer deposited buffer layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hultqvist, Adam; Bent, Stacey F.; Li, Jian V.

2015-07-20

Partial CuInGaSe{sub 2} (CIGS) solar cell stacks with different atomic layer deposited buffer layers and pretreatments were analyzed by photoluminescence (PL) and capacitance voltage (CV) measurements to investigate the buffer layer/CIGS interface. Atomic layer deposited ZnS, ZnO, and SnO{sub x} buffer layers were compared with chemical bath deposited CdS buffer layers. Band bending, charge density, and interface state density were extracted from the CV measurement using an analysis technique new to CIGS. The surface recombination velocity calculated from the density of interface traps for a ZnS/CIGS stack shows a remarkably low value of 810 cm/s, approaching the range of single crystallinemore » II–VI systems. Both the PL spectra and its lifetime depend on the buffer layer; thus, these measurements are not only sensitive to the absorber but also to the absorber/buffer layer system. Pretreatment of the CIGS prior to the buffer layer deposition plays a significant role on the electrical properties for the same buffer layer/CIGS stack, further illuminating the importance of good interface formation. Finally, ZnS is found to be the best performing buffer layer in this study, especially if the CIGS surface is pretreated with potassium cyanide.« less

Reducing interface recombination for Cu(In,Ga)Se 2 by atomic layer deposited buffer layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hultqvist, Adam; Li, Jian V.; Kuciauskas, Darius

2015-07-20

Partial CuInGaSe2 (CIGS) solar cell stacks with different atomic layer deposited buffer layers and pretreatments were analyzed by photoluminescence (PL) and capacitance voltage (CV) measurements to investigate the buffer layer/CIGS interface. Atomic layer deposited ZnS, ZnO, and SnOx buffer layers were compared with chemical bath deposited CdS buffer layers. Band bending, charge density, and interface state density were extracted from the CV measurement using an analysis technique new to CIGS. The surface recombination velocity calculated from the density of interface traps for a ZnS/CIGS stack shows a remarkably low value of 810 cm/s, approaching the range of single crystalline II-VImore » systems. Both the PL spectra and its lifetime depend on the buffer layer; thus, these measurements are not only sensitive to the absorber but also to the absorber/buffer layer system. Pretreatment of the CIGS prior to the buffer layer deposition plays a significant role on the electrical properties for the same buffer layer/CIGS stack, further illuminating the importance of good interface formation. Finally, ZnS is found to be the best performing buffer layer in this study, especially if the CIGS surface is pretreated with potassium cyanide.« less

Reducing interface recombination for Cu(In,Ga)Se 2 by atomic layer deposited buffer layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hultqvist, Adam; Li, Jian V.; Kuciauskas, Darius

2015-07-20

Partial CuInGaSe2 (CIGS) solar cell stacks with different atomic layer deposited buffer layers and pretreatments were analyzed by photoluminescence (PL) and capacitance voltage (CV) measurements to investigate the buffer layer/CIGS interface. Atomic layer deposited ZnS, ZnO, and SnOx buffer layers were compared with chemical bath deposited CdS buffer layers. Band bending, charge density, and interface state density were extracted from the CV measurement using an analysis technique new to CIGS. The surface recombination velocity calculated from the density of interface traps for a ZnS/CIGS stack shows a remarkably low value of 810 cm/s, approaching the range of single crystalline II–VImore » systems. Both the PL spectra and its lifetime depend on the buffer layer; thus, these measurements are not only sensitive to the absorber but also to the absorber/buffer layer system. Pretreatment of the CIGS prior to the buffer layer deposition plays a significant role on the electrical properties for the same buffer layer/CIGS stack, further illuminating the importance of good interface formation. Finally, ZnS is found to be the best performing buffer layer in this study, especially if the CIGS surface is pretreated with potassium cyanide.« less

Controlling the physical parameters of crystalline CIGS nanowires for use in superstrate configuration using vapor phase epitaxy

NASA Astrophysics Data System (ADS)

Lee, Dongjin; Jeon, H. C.; Kang, T. W.; Kumar, Sunil

2018-03-01

Indium tin oxide (ITO) is a suitable candidate for smart windows and bifacial semi-transparent solar cell applications. In this study, highly crystalline CuInGaSe2 (CIGS) nanowires were successfully grown by horizontal-type vapor phase epitaxy on an ITO substrate. Length, diameter, and density of the nanowires were studied by varying the growth temperature (500, 520, and 560 °C), time (3.5, 6.5, and 9.5 h), and type of catalyst (In, Au, and Ga). Length, diameter, and density of the nanowires were found to be highly dependent on the growth conditions. At an optimized growth period and temperature of 3.5 h and 520 °C, respectively, the length and diameter of the nanowires were found to increase when grown in a catalyst-free environment. However, the density of the nanowires was found to be higher while using a catalyst during growth. Even in a catalyst-free environment, an Indium cluster formed at the bottom of the nanowires. The source of these nanowires is believed to be Indium from the ITO substrate which was observed in the EDS measurement. TEM-based EDS and line EDS indicated that the nanowires are made up of CIGS material with a very low Gallium content. XRD measurements also show the appearance of wurtzite CIS nanowires grown on ITO in addition to the chalcopyrite phase. PL spectroscopy was done to see the near-band-edge emission for finding band-to-band optical transition in this material. Optical response of the CIGS nanowire network was also studied to see the photovoltaic effect. This work creates opportunities for making real solar cell devices in superstrate configuration.

Core Levels, Band Alignments, and Valence-Band States in CuSbS 2 for Solar Cell Applications

DOE PAGES

Whittles, Thomas J.; Veal, Tim D.; Savory, Christopher N.; ...

2017-11-10

The earth-abundant material CuSbS 2 (CAS) has shown good optical properties as a photovoltaic solar absorber material, but has seen relatively poor solar cell performance. To investigate the reason for this anomaly, the core levels of the constituent elements, surface contaminants, ionization potential, and valence-band spectra are studied by X-ray photoemission spectroscopy. The ionization potential and electron affinity for this material (4.98 and 3.43 eV) are lower than those for other common absorbers, including CuInxGa (1-x)Se 2 (CIGS). Experimentally corroborated density functional theory (DFT) calculations show that the valence band maximum is raised by the lone pair electrons from themore » antimony cations contributing additional states when compared with indium or gallium cations in CIGS. The resulting conduction band misalignment with CdS is a reason for the poor performance of cells incorporating a CAS/CdS heterojunction, supporting the idea that using a cell design analogous to CIGS is unhelpful. These findings underline the critical importance of considering the electronic structure when selecting cell architectures that optimize open-circuit voltages and cell efficiencies.« less

Core Levels, Band Alignments, and Valence-Band States in CuSbS2 for Solar Cell Applications.

PubMed

Whittles, Thomas J; Veal, Tim D; Savory, Christopher N; Welch, Adam W; de Souza Lucas, Francisco Willian; Gibbon, James T; Birkett, Max; Potter, Richard J; Scanlon, David O; Zakutayev, Andriy; Dhanak, Vinod R

2017-12-06

The earth-abundant material CuSbS 2 (CAS) has shown good optical properties as a photovoltaic solar absorber material, but has seen relatively poor solar cell performance. To investigate the reason for this anomaly, the core levels of the constituent elements, surface contaminants, ionization potential, and valence-band spectra are studied by X-ray photoemission spectroscopy. The ionization potential and electron affinity for this material (4.98 and 3.43 eV) are lower than those for other common absorbers, including CuIn x Ga (1-x) Se 2 (CIGS). Experimentally corroborated density functional theory (DFT) calculations show that the valence band maximum is raised by the lone pair electrons from the antimony cations contributing additional states when compared with indium or gallium cations in CIGS. The resulting conduction band misalignment with CdS is a reason for the poor performance of cells incorporating a CAS/CdS heterojunction, supporting the idea that using a cell design analogous to CIGS is unhelpful. These findings underline the critical importance of considering the electronic structure when selecting cell architectures that optimize open-circuit voltages and cell efficiencies.

Structural investigation of MF, RF and DC sputtered Mo thin films for backside photovoltaic electrode

NASA Astrophysics Data System (ADS)

Małek, Anna K.; Marszałek, Konstanty W.; Rydosz, Artur M.

2016-12-01

Recently photovoltaics attracts much attention of research and industry. The multidirectional studies are carried out in order to improve solar cells performance, the innovative materials are still searched and existing materials and technology are optimized. In the multilayer structure of CIGS solar cells molybdenum (Mo) layer is used as a back contact. Mo layers meet all requirements for back side electrode: low resistivity, good adhesion to the substrate, high optical reflection in the visible range, columnar structure for Na ions diffusion, formation of an ohmic contact with the ptype CIGS absorber layer, and high stability during the corrosive selenization process. The high adhesion to the substrate and low resistivity in single Mo layer is difficult to be achieved because both properties depend on the deposition parameters, particularly on working gas pressure. Therefore Mo bilayers are applied as a back contact for CIGS solar cells. In this work the Mo layers were deposited by medium frequency sputtering at different process parameters. The effect of substrate temperature within the range of 50°C-200°C and working gas pressure from 0.7 mTorr to 7 mTorr on crystalline structure of Mo layers was studied.

Evidence for Cu2-xSe platelets at grain boundaries and within grains in Cu(In,Ga)Se2 thin films

NASA Astrophysics Data System (ADS)

Simsek Sanli, E.; Ramasse, Q. M.; Mainz, R.; Weber, A.; Abou-Ras, D.; Sigle, W.; van Aken, P. A.

2017-07-01

Cu(In,Ga)Se2 (CIGS)-based solar cells reach high power-conversion efficiencies of above 22%. In this work, a three-stage co-evaporation method was used for their fabrication. During the growth stages, the stoichiometry of the absorbers changes from Cu-poor ([Cu]/([In] + [Ga]) < 1) to Cu-rich ([Cu]/([In] + [Ga]) > 1) and finally becomes Cu-poor again when the growth process is completed. It is known that, according to the Cu-In-Ga-Se phase diagram, a Cu-rich growth leads to the presence of Cu2-xSe (x = 0-0.25), which is assumed to assist in recrystallization, grain growth, and defect annihilation in the CIGS layer. So far, Cu2-xSe precipitates with spatial extensions on the order of 10-100 nm have been detected only in Cu-rich CIGS layers. In the present work, we report Cu2-xSe platelets with widths of only a few atomic planes at grain boundaries and as inclusions within grains in a polycrystalline, Cu-poor CIGS layer, as evidenced by high-resolution scanning transmission electron microscopy (STEM). The chemistry of the Cu-Se secondary phase was analyzed by electron energy-loss spectroscopy, and STEM image simulation confirmed the identification of the detected phase. These results represent additional experimental evidence for the proposed topotactical growth model for Cu-Se-assisted CIGS thin-film formation under Cu-rich conditions.

Leading Solar Expertise-A Launch Pad to the Future - Continuum Magazine

Science.gov Websites

&D Magazine and identify each technology as one of the top 100 technological innovations of the 1996 for copper indium gallium diselenide (CIGS). One of the more popular thin-film solar cells to be of the world's first solar power towers-Solar One and Solar Two, shown here. CSP systems produce

$6 Million in Awards to Advance Solar Cell Research

Science.gov Websites

five companies for high tech research into non-conventional, photovoltaic technologies for creating can have significant cost advantages over conventional technologies. This non-conventional solar , Newbury Park, $498,000 (small business) Project Title: Non-Vacuum Processing of CIGS Solar Cells Project

Investigation of defect properties in Cu(In,Ga)Se 2 solar cells by deep-level transient spectroscopy

NASA Astrophysics Data System (ADS)

Kerr, L. L.; Li, Sheng S.; Johnston, S. W.; Anderson, T. J.; Crisalle, O. D.; Kim, W. K.; Abushama, J.; Noufi, R. N.

2004-09-01

The performance of the chalcopyrite material Cu(In,Ga)Se 2 (CIGS) used as an absorber layer in thin-film photovoltaic devices is significantly affected by the presence of native defects. The deep-level transient spectroscopy (DLTS) technique is used in this work to characterize the defect properties, yielding relevant information about the defect types, their capture cross-sections, and energy levels and densities in the CIGS cells. Three solar cells developed using different absorber growth technologies were analyzed using DLTS, capacitance-voltage ( C- V), and capacitance-temperature ( C- T) techniques. It was found that CIS cells grown at the University of Florida exhibits a middle-gap defect level that may relate to the cell's low fill factor and open-circuit voltage values observed. A high efficiency ( ηc>18%) CIGS cell produced by the National Renewable Energy Laboratory (NREL) was found to contain three minority-carrier (electron) traps and a 13% CIGS cell produced by the Energy Photovoltaics Inc. (EPV) exhibited one majority (hole) trap. The approach followed using the DLTS technique serves as a paradigm for revealing the presence of significant defect levels in absorber materials, and may be used to support the identification of remedial processing operations.

Understanding the Effect of Na in Improving the Performance of CuInSe 2 Based Photovoltaics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dobson, Kevin D.

Cu(In,Ga)Se 2 (CIGS) thin film photovoltaic technology is in the early stages of commercialization with an annual manufacturing capacity over 1 GW and has demonstrated the highest module efficiency of any of the thin film technologies. However there still is a lack of fundamental understanding of the relationship between the material properties and solar cell device operation. It is well known that the incorporation of a small amount of Na into the CIGS film during processing is essential for high efficiency devices. However, there are conflicting explanations for how Na behaves at the atomic scale. This report investigates how Namore » is incorporated into the CIGS device structure and evaluates the diffusion of Na into CIGS grain boundaries (GBs) and bulk crystallites. Participants: This project was carried out at the Institute of Energy Conversion at the University of Delaware, collaborating with the Rockett group at the University of Illinois Urbana-Champagne. Significant Findings: The significant outcomes of this project for each task include; Task 1.0: Effect of Na in Devices Fabricated on PVD Deposited CIGS; Na diffusion occurs through the Mo back contact via GBs driven by the presence of oxygen; Na reversibly compensates donor defects in CIGS GBs,Task 2.0: Na Incorporation in Single Crystal CIGS; and bulk Na diffusion proceeds rapidly such that grains are Na-saturated immediately following CIGS thin film manufacture. Industry Guidance: The presented results offer interesting concepts for modification of manufacturing processes of CIGS-based PV modules. Possible approaches to improve control of Na uptake and uniformly increase levels in CIGS films are highlighted for processes that employ either soda-lime glass or NaF as the Na source. Concepts include the potential of O 2 or oxidative based treatments of Mo back contacts to improve Na diffusion through the metal film and increase Na uptake into the growing CIGS. This project has also offered fundamental understanding of the behavior of Na in CIGS grains and GBs, particularly the confirmation that CIGS grains will be saturated with Na immediately following manufacture Summary of Results: Most commercially available CIGS modules are fabricated on soda-lime glass coated with Mo as the back electric contact, and Na in the glass diffuses through the Mo layer into the CIGS during film growth. In Task 1 the transport of Na through Mo was evaluated using x-ray photoelectron surface spectroscopy along with diffusion modeling to obtain diffusion coefficients at several temperatures. It was determined that Na diffusion in Mo only occurs along GBs and that oxygen provides an additional driving force to enhance Na transport. Device data revealed that older Mo substrates with a greater amount of surface oxide resulted in slightly higher efficiencies due to enhanced Na incorporation caused by the oxide. This finding shows that Mo substrates could potentially undergo an oxidation treatment prior to CIGS deposition to further improve and control the incorporation of Na. To determine if in-grain Na affects device performance, in Task 1 Na was selectively removed from GBs using heat/rinse cycles. Due to the low temperature of this treatment, Na at GBS remained mobile while diffusion within the bulk was too slow for Na removal from the grain interiors. Changes in electrical properties were evaluated using conductivity and Seebeck coefficient measurements, with both decreasing as Na was removed to reach values similar to Na-free controls samples. This can be explained by the compensation of donor defects by Na, causing an increase in the free carrier concentration. Devices showed a decrease in open-circuit voltage after Na removal confirming that the beneficial effects of GB Na. The findings of this project will provide guidance for rational optimization of Na incorporation procedures in the manufacturing of CIGS solar cells. While it is known that Na segregates at CIGS GBs, the nature and role of Na diffusion into grain interiors was less clear. In Task 2, single crystal CuInSe 2 was used as a model system to represent the grain interiors of CIGS. Crystals processed by two different methods of different compositions and dislocation densities, were evaluated. Diffusion coefficients were obtained at two temperatures after Na diffusion, giving near identical values, ~2x10 11 cm 2/s and ~6x10 11 cm2/s at 420°C and 480°C, respectively, for each crystal. Characterization confirmed that dislocation densities were too low to significantly impact the effective diffusion coefficient. The Cu-poor crystal had a higher solubility suggesting that Na diffusion is mediated by Cu-vacancies, but was not accompanied by an expected increase in diffusion coefficient. The activation energy for diffusion was similar to values expected for interstitial diffusion, but the large size of Na + ions should result in a solubility that is much lower than what was experimentally measured. A hybrid interstitial-substitutional mechanism is proposed that combines the fast diffusion of interstitial atoms with the high solubility common for substitutional impurities. Lattice diffusion of Na proceeds fast enough that CIGS grain interiors will have Na concentrations near the solubility limit of 1018 cm -3 when manufactured under standard conditions. Na and K treated epitaxial CIS films showed a significant increase in cathodoluminescence emission intensity, indicating a reduction of non-radiative recombination pathways, which is consistent with improvements in CIGS device performance, though the mechanism is not clear. Pathways forward: Despite the success of this project, there are a number of questions remaining related to further the understanding of the chemistry of Na in CIGS films and devices. These include further elucidation of the mechanisms of Na passivation in CIGS GBs, with identification of which defects are involved and confirmation of the possible effects of in-grain Na on device performance. To complete analysis of the cell structure, conformation of the presence and possible chemistries of Na at the CIGS/CdS junction and/or in the front transparent contacts, and its effects on device performance, is needed.« less

Materials and Devices | Photovoltaic Research | NREL

Science.gov Websites

Polycrystalline Thin-Film PV Cadmium telluride (CdTe) solar cells Copper indium gallium diselenide (CIGS) solar cells Perovskite and Organic PV Perovskite solar cells Perovskite Patent Portfolio Organic PV (OPV ) solar cells Advanced Materials, Devices, and Concepts We explore new PV materials using high-throughput

Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique

DOE PAGES

Khatavkar, Sanchit; Muniappan, Kulasekaran; Kannan, Chinna V.; ...

2017-11-10

Excess carrier lifetime plays a crucial role in determining the efficiency of solar cells. In this paper, we use the frequency dependence of inphase and quadrature components of modulated electroluminescence (MEL) to measure the relaxation time (decay) of excess carriers. The advantage of the MEL technique is that the relaxation time is obtained directly from the angular frequency at which the quadrature component peaks. It does not need knowledge of the material parameters like mobility, etc., and can be used for any finished solar cells which have detectable light emission. The experiment is easy to perform with standard electrical equipment.more » For silicon solar cells, the relaxation time is dominated by recombination and hence, the relaxation time is indeed the excess carrier lifetime. In contrast, for the CIGS solar cells investigated here, the relaxation time is dominated by trapping and emission from shallow minority carrier traps.« less

Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khatavkar, Sanchit; Muniappan, Kulasekaran; Kannan, Chinna V.

Excess carrier lifetime plays a crucial role in determining the efficiency of solar cells. In this paper, we use the frequency dependence of inphase and quadrature components of modulated electroluminescence (MEL) to measure the relaxation time (decay) of excess carriers. The advantage of the MEL technique is that the relaxation time is obtained directly from the angular frequency at which the quadrature component peaks. It does not need knowledge of the material parameters like mobility, etc., and can be used for any finished solar cells which have detectable light emission. The experiment is easy to perform with standard electrical equipment.more » For silicon solar cells, the relaxation time is dominated by recombination and hence, the relaxation time is indeed the excess carrier lifetime. In contrast, for the CIGS solar cells investigated here, the relaxation time is dominated by trapping and emission from shallow minority carrier traps.« less

Comparison of CIGS solar cells made with different structures and fabrication techniques

DOE PAGES

Mansfield, Lorelle M.; Garris, Rebekah L.; Counts, Kahl D.; ...

2016-11-03

Cu(In, Ga)Se2 (CIGS)-based solar cells from six fabricators were characterized and compared. The devices had differing substrates, absorber deposition processes, buffer materials, and contact materials. The effective bandgaps of devices varied from 1.05 to 1.22 eV, with the lowest optical bandgaps occurring in those with metal-precursor absorber processes. Devices with Zn(O, S) or thin CdS buffers had quantum efficiencies above 90% down to 400 nm. Most voltages were 250-300 mV below the Shockley-Queisser limit for their bandgap. Electroluminescence intensity tracked well with the respective voltage deficits. Fill factor (FF) was as high as 95% of the maximum for each device'smore » respective current and voltage, with higher FF corresponding to lower diode quality factors (~1.3). An in-depth analysis of FF losses determined that diode quality reflected in the quality factor, voltage-dependent photocurrent, and, to a lesser extent, the parasitic resistances are the limiting factors. As a result, different absorber processes and device structures led to a range of electrical and physical characteristics, yet this investigation showed that multiple fabrication pathways could lead to high-quality and high-efficiency solar cells.« less

Comparison of CIGS solar cells made with different structures and fabrication techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mansfield, Lorelle M.; Garris, Rebekah L.; Counts, Kahl D.

Cu(In, Ga)Se2 (CIGS)-based solar cells from six fabricators were characterized and compared. The devices had differing substrates, absorber deposition processes, buffer materials, and contact materials. The effective bandgaps of devices varied from 1.05 to 1.22 eV, with the lowest optical bandgaps occurring in those with metal-precursor absorber processes. Devices with Zn(O, S) or thin CdS buffers had quantum efficiencies above 90% down to 400 nm. Most voltages were 250-300 mV below the Shockley-Queisser limit for their bandgap. Electroluminescence intensity tracked well with the respective voltage deficits. Fill factor (FF) was as high as 95% of the maximum for each device'smore » respective current and voltage, with higher FF corresponding to lower diode quality factors (~1.3). An in-depth analysis of FF losses determined that diode quality reflected in the quality factor, voltage-dependent photocurrent, and, to a lesser extent, the parasitic resistances are the limiting factors. As a result, different absorber processes and device structures led to a range of electrical and physical characteristics, yet this investigation showed that multiple fabrication pathways could lead to high-quality and high-efficiency solar cells.« less

Characterization of Cu(In,Ga)Se 2 (CIGS) films with varying gallium ratios

DOE PAGES

Claypoole, Jesse; Peace, Bernadette; Sun, Neville; ...

2015-09-05

Cu(In 1–x,Ga x)Se 2 (CIGS) absorber layers were deposited on molybdenum (Mo) coated soda-lime glass substrates with varying Ga content (described as Ga/(In + Ga) ratios) with respect to depth. As the responsible mechanisms for the limitation of the performance of the CIGS solar cells with high Ga contents are not well understood, the goal of this work was to investigate different properties of CIGS absorber films with Ga/(In + Ga) ratios varied between 0.29 and 0.41 (as determined by X-ray florescence spectroscopy (XRF)) in order to better understand the role that the Ga content has on film quality. Themore » Ga grading in the CIGS layer has the effect causing a higher band gap toward the surface and Mo contact while the band gap in the middle of the CIGS layer is lower. Also, a wider and larger Ga/(In + Ga) grading dip located deeper in the CIGS absorber layers tend to produce larger grains in the regions of the films that have lower Ga/(In + Ga) ratios. Moreover, it was found that surface roughness decreases from 51.2 nm to 41.0 nm with increasing Ga/(In + Ga) ratios. Furthermore, the surface roughness generally decreases if the Ga grading occurs deeper in the absorber layer.« less

Modeling and Optimization of Sub-Wavelength Grating Nanostructures on Cu(In,Ga)Se2 Solar Cell

NASA Astrophysics Data System (ADS)

Kuo, Shou-Yi; Hsieh, Ming-Yang; Lai, Fang-I.; Liao, Yu-Kuang; Kao, Ming-Hsuan; Kuo, Hao-Chung

2012-10-01

In this study, an optical simulation of Cu(In,Ga)Se2 (CIGS) solar cells by the rigorous coupled-wave analysis (RCWA) method is carried out to investigate the effects of surface morphology on the light absorption and power conversion efficiencies. Various sub-wavelength grating (SWG) nanostructures of periodic ZnO:Al (AZO) on CIGS solar cells were discussed in detail. SWG nanostructures were used as efficient antireflection layers. From the simulation results, AZO structures with nipple arrays effectively suppress the Fresnel reflection compared with nanorod- and cone-shaped AZO structures. The optimized reflectance decreased from 8.44 to 3.02% and the efficiency increased from 14.92 to 16.11% accordingly. The remarkable enhancement in light harvesting is attributed to the gradient refractive index profile between the AZO nanostructures and air.

Hydrazine-Free Solution-Deposited CuIn(S,Se)2 Solar Cells by Spray Deposition of Metal Chalcogenides.

PubMed

Arnou, Panagiota; van Hest, Maikel F A M; Cooper, Carl S; Malkov, Andrei V; Walls, John M; Bowers, Jake W

2016-05-18

Solution processing of semiconductors, such as CuInSe2 and its alloys (CIGS), can significantly reduce the manufacturing costs of thin film solar cells. Despite the recent success of solution deposition approaches for CIGS, toxic reagents such as hydrazine are usually involved, which introduce health and safety concerns. Here, we present a simple and safer methodology for the preparation of high-quality CuIn(S, Se)2 absorbers from metal sulfide solutions in a diamine/dithiol mixture. The solutions are sprayed in air, using a chromatography atomizer, followed by a postdeposition selenization step. Two different selenization methods are explored resulting in power conversion efficiencies of up to 8%.

High-Resolution AES Mapping and TEM Study of Cu(In,Ga)Se2 Thin Film Growth: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perkins, C. L.; Yan, Y.; Jones, K.

2001-10-01

Presented at 2001 NCPV Program Review Meeting: TEM and high-resolution AES mapping data on CIGS samples. The chalcopyrite Cu(In,Ga)Se{sub 2} (CIGS) shows promise as an absorber layer in thin polycrystalline solar cells, however, details of the PVD growth of this complicated material remain in a developing stage. Previous workers have postulated the existence of a thin film of liquid Cu{sub x}Se on the growing CIGS film, and that this layer acts as a reservoir of copper as well as a layer in which rapid mass transport is possible. In this paper we present transmission electron microscopy (TEM) and high resolutionmore » Auger electron spectroscopy (AES) mapping data taken on samples that had their growth interrupted at a stage when Cu{sub x}Se was expected to be present. The AES maps show CIGS grains which are highly enriched in copper relative to the rest of the CIGS film, and that these same areas contain almost no indium, results consistent with the presence of CuxSe. Small-area diffraction analysis and energy dispersive spectroscopy (EDS) performed on these same samples independently confirm the presence of Cu{sub x}Se at the surface of growing CIGS films.« less

The Status and Outlook for the Photovoltaics Industry

NASA Astrophysics Data System (ADS)

Carlson, David

2006-03-01

The first silicon solar cell was made at Bell Labs in 1954, and over the following decades, shipments of photovoltaic (PV) modules increased at a rate of about 18% annually. In the last several years, the annual growth rate has increased to ˜ 35% due largely to government-supported programs in Japan and Germany. Silicon technology has dominated the PV industry since its inception, and in 2005 about 65% of all solar cells were made from polycrystalline (or multicrystalline) silicon, 24% from monocrystalline silicon and ˜ 4% from ribbon silicon. While conversion efficiencies as high as 24.7% have been obtained in the laboratory for silicon solar cells, the best efficiencies for commercial PV modules are in the range of 17 18% (the efficiency limit for a silicon solar cell is ˜ 29%). A number of companies are commercializing solar cells based on other materials such as amorphous silicon, microcrystalline silicon, cadmium telluride, copper-indium-gallium-diselenide (CIGS), gallium arsenide (and related compounds) and dye- sensitized titanium oxide. Thin film CIGS solar cells have been fabricated with conversion efficiencies as high as 19.5% while efficiencies as high as 39% have been demonstrated for a GaInP/Ga(In)As/Ge triple-junction cell operating at a concentration of 236 suns. Thin film solar cells are being used in consumer products and in some building-integrated applications, while PV concentrator systems are being tested in grid-connected arrays located in high solar insolation areas. Nonetheless, crystalline silicon PV technology is likely to dominate the terrestrial market for at least the next decade with module efficiencies > 20% and module prices of < 1/Wp expected by 2020, which in turn should allow significant penetration of the utility grid market. However, crystalline silicon solar cells may be challenged in the next decade or two by new low-cost, high performance devices based on organic materials and nanotechnology.

Depth Profile of Impurity Phase in Wide-Bandgap Cu(In1-x ,Ga x )Se2 Film Fabricated by Three-Stage Process

NASA Astrophysics Data System (ADS)

Wang, Shenghao; Nazuka, Takehiro; Hagiya, Hideki; Takabayashi, Yutaro; Ishizuka, Shogo; Shibata, Hajime; Niki, Shigeru; Islam, Muhammad M.; Akimoto, Katsuhiro; Sakurai, Takeaki

2018-02-01

For copper indium gallium selenide [Cu(In1-x ,Ga x )Se2, CIGS]-based solar cells, defect states or impurity phase always form due to both the multinary compositions of CIGS film and the difficulty of controlling the growth process, especially for high Ga concentration. To further improve device performance, it is important to understand such formation of impurity phase or defect states during fabrication. In the work presented herein, the formation mechanism of impurity phase Cu2-δ Se and its depth profile in CIGS film with high Ga content, in particular CuGaSe2 (i.e., CGS), were investigated by applying different growth conditions (i.e., normal three-stage process and two-cycle three-stage process). The results suggest that impurity phase Cu2-δ Se is distributed nonuniformly in the film because of lack of Ga diffusion. The formed Cu2-δ Se can be removed by etching the as-deposited CGS film with bromine-methanol solution, resulting in improved device performance.

Challenges to Scaling CIGS Photovoltaics

NASA Astrophysics Data System (ADS)

Stanbery, B. J.

2011-03-01

The challenges of scaling any photovoltaic technology to terawatts of global capacity are arguably more economic than technological or resource constraints. All commercial thin-film PV technologies are based on direct bandgap semiconductors whose absorption coefficient and bandgap alignment with the solar spectrum enable micron-thick coatings in lieu to hundreds of microns required using indirect-bandgap c-Si. Although thin-film PV reduces semiconductor materials cost, its manufacture is more capital intensive than c-Si production, and proportional to deposition rate. Only when combined with sufficient efficiency and cost of capital does this tradeoff yield lower manufacturing cost. CIGS has the potential to become the first thin film technology to achieve the terawatt benchmark because of its superior conversion efficiency, making it the only commercial thin film technology which demonstrably delivers performance comparable to the dominant incumbent, c-Si. Since module performance leverages total systems cost, this competitive advantage bears directly on CIGS' potential to displace c-Si and attract the requisite capital to finance the tens of gigawatts of annual production capacity needed to manufacture terawatts of PV modules apace with global demand growth.

High Performance Tandem Perovskite/Polymer Solar Cells

NASA Astrophysics Data System (ADS)

Liu, Yao; Bag, Monojit; Page, Zachariah; Renna, Lawrence; Kim, Paul; Choi, Jaewon; Emrick, Todd; Venkataraman, D.; Russell, Thomas

Combining perovskites with other inorganic materials, such as copper indium gallium diselenide (CIGS) or silicon, is enabling significant improvement in solar cell device performance. Here, we demonstrate a highly efficient hybrid tandem solar cell fabricated through a facile solution deposition approach to give a perovskite front sub-cell and a polymer:fullerene blend back sub-cell. This methodology eliminates the adverse effects of thermal annealing during perovskite fabrication on polymer solar cells. The record tandem solar cell efficiency of 15.96% is 40% greater than the corresponding perovskite-based single junction device and 65% greater than the polymer-based single junction device, while mitigating deleterious hysteresis effects often associated with perovskite solar cells. The hybrid tandem devices demonstrate the synergistic effects arising from the combination of perovskite and polymer-based materials for solar cells. This work was supported by the Department of Energy-supported Energy Frontier Research Center at the University of Massachusetts (DE-SC0001087). The authors acknowledge the W.M. Keck Electron Microscopy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whittles, Thomas J.; Veal, Tim D.; Savory, Christopher N.

The earth-abundant material CuSbS 2 (CAS) has shown good optical properties as a photovoltaic solar absorber material, but has seen relatively poor solar cell performance. To investigate the reason for this anomaly, the core levels of the constituent elements, surface contaminants, ionization potential, and valence-band spectra are studied by X-ray photoemission spectroscopy. The ionization potential and electron affinity for this material (4.98 and 3.43 eV) are lower than those for other common absorbers, including CuInxGa (1-x)Se 2 (CIGS). Experimentally corroborated density functional theory (DFT) calculations show that the valence band maximum is raised by the lone pair electrons from themore » antimony cations contributing additional states when compared with indium or gallium cations in CIGS. The resulting conduction band misalignment with CdS is a reason for the poor performance of cells incorporating a CAS/CdS heterojunction, supporting the idea that using a cell design analogous to CIGS is unhelpful. These findings underline the critical importance of considering the electronic structure when selecting cell architectures that optimize open-circuit voltages and cell efficiencies.« less

Recent Progress in Nanoelectrical Characterizations of CdTe and Cu(In,Ga)Se2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Chun-Sheng; To, Bobby; Glynn, Stephen

2016-11-21

We report two recent nanoelectrical characterizations of CdTe and Cu(In, Ga)Se2 (CIGS) thin-film solar cells by developing atomic force microscopy-based nanoelectrical probes. Charges trapped at defects at the CdS/CdTe interface were probed by Kelvin probe force microscopy (KPFM) potential mapping and by ion-milling the CdTe superstrate device in a bevel glancing angle of ~0.5 degrees. The results show randomly distributed donor-like defects at the interface. The effect of K post-deposition treatment on the near-surface region of the CIGS film was studied by KPFM potential and scanning spreading resistance microscopy (SSRM) resistivity mapping, which shows passivation of grain-boundary potential and improvementmore » of resistivity uniformity by the K treatment.« less

Transport Imaging of Multi-Junction and CIGS Solar Cell Materials

DTIC Science & Technology

2011-12-01

solar cells start with the material charge transport parameters, namely the charge mobility, lifetime and diffusion length . It is the goal of...every solar cell manufacturer to maintain high carrier lifetime so as to realize long diffusion lengths . Long diffusion lengths ensure that the charges...Thus, being able to accurately determine the diffusion length of any solar cell material proves advantageous by providing insights

Recent Progress in CuInS2 Thin-Film Solar Cell Research at NASA Glenn

NASA Technical Reports Server (NTRS)

Jin, M. H.-C.; Banger, K. K.; Kelly, C. V.; Scofield, J. H.; McNatt, J. S.; Dickman, J. E.; Hepp, A. F.

2005-01-01

The National Aeronautics and Space Administration (NASA) is interested in developing low-cost highly efficient solar cells on light-weight flexible substrates, which will ultimately lower the mass-specific power (W/kg) of the cell allowing extra payload for missions in space as well as cost reduction. In addition, thin film cells are anticipated to have greater resistance to radiation damage in space, prolonging their lifetime. The flexibility of the substrate has the added benefit of enabling roll-to-roll processing. The first major thin film solar cell was the "CdS solar cell" - a heterojunction between p-type CuxS and n-type CdS. The research on CdS cells started in the late 1950s and the efficiency in the laboratory was up to about 10 % in the 1980s. Today, three different thin film materials are leading the field. They include amorphous Si, CdTe, and Cu(In,Ga)Se2 (CIGS). The best thin film solar cell efficiency of 19.2 % was recently set by CIGS on glass. Typical module efficiencies, however, remain below 15 %.

Soft X-ray absorption spectroscopy investigation of the surface chemistry and treatments of copper indium gallium diselenide (CIGS)

DOE PAGES

Schwartz, Craig; Nordlund, Dennis; Sokaras, Dimosthenis; ...

2017-02-01

The surface and near surface structure of copper-indium-gallium-selenide (CIGS) absorber layers is integral to the producing a high-quality photovoltaic junction. By using X-ray absorption spectroscopy (XAS) and monitoring multiple elemental absorption edges with both theory and experiment, we are able to identify several features of the surface of CIGS as a function of composition and surface treatments. The XAS data shows trends in the near surface region of oxygen, copper, indium and gallium species as the copper content is varied in the films. The oxygen surface species are also monitored through a series of experiments that systematically investigates the effectsmore » of water and various solutions of: ammonium hydroxide, cadmium sulfate, and thiourea. These being components of cadmium sulfide chemical bath deposition (CBD). Characteristics of the CBD are correlated with a restorative effect that produces as normalized, uniform surface chemistry as measured by XAS. This surface chemistry is found in CIGS solar cells with excellent power conversion efficiency (<19%). The results provide new insight for CIGS processing strategies that seek to replace CBD and/or cadmium sulfide.« less

Soft X-ray absorption spectroscopy investigation of the surface chemistry and treatments of copper indium gallium diselenide (CIGS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwartz, Craig; Nordlund, Dennis; Sokaras, Dimosthenis

The surface and near surface structure of copper-indium-gallium-selenide (CIGS) absorber layers is integral to the producing a high-quality photovoltaic junction. By using X-ray absorption spectroscopy (XAS) and monitoring multiple elemental absorption edges with both theory and experiment, we are able to identify several features of the surface of CIGS as a function of composition and surface treatments. The XAS data shows trends in the near surface region of oxygen, copper, indium and gallium species as the copper content is varied in the films. The oxygen surface species are also monitored through a series of experiments that systematically investigates the effectsmore » of water and various solutions of: ammonium hydroxide, cadmium sulfate, and thiourea. These being components of cadmium sulfide chemical bath deposition (CBD). Characteristics of the CBD are correlated with a restorative effect that produces as normalized, uniform surface chemistry as measured by XAS. This surface chemistry is found in CIGS solar cells with excellent power conversion efficiency (<19%). The results provide new insight for CIGS processing strategies that seek to replace CBD and/or cadmium sulfide.« less

Preparation of CIGS-based solar cells using a buffered electrodeposition bath

DOEpatents

Bhattacharya, Raghu Nath

2007-11-20

A photovoltaic cell exhibiting an overall conversion efficiency of at least 9.0% is prepared from a copper-indium-gallium-diselenide thin film. The thin film is prepared by simultaneously electroplating copper, indium, gallium, and selenium onto a substrate using a buffered electro-deposition bath. The electrodeposition is followed by adding indium to adjust the final stoichiometry of the thin film.

Efficiency loss of thin film Cu(InxGa1-x)Se(S) solar panels by lamination process

NASA Astrophysics Data System (ADS)

Xu, Li

2017-04-01

Efficiency loss of thin film Cu(InxGa1-x)Se(S) (CIGS) solar panels by lamination process has been compromising the final output power in commercial products of solar modules, but few reports have been published on such issue, as the majority of the investigation is focused on the efficiency at the circuit level, i.e., before lamination process. In this paper, we studied the effect of lamination process to the efficiency loss of thin film CIGS solar panels. It was observed that the fill factor degradation dominated the efficiency loss with the small change of Voc and Jsc. Experiments showed that neither the temperature nor the pressure, nor the two combined in the lamination process is the root cause of the efficiency loss; instead, the ethylene vinyl acetate (EVA) layer as the encapsulation material which directly contacts the solar cell devices was the major factor responsible for the efficiency loss. It was found that the gel content of the cured EVA film after lamination was highly correlated to the efficiency loss. The higher the gel content, the higher the efficiency loss. The mismatch of coefficient of thermal expansion between the EVA film and the CIGS thin film resulted in compressive stress in the device layer after lamination process. The compressive stress is speculated to affect the lattice defects, but need to be confirmed with the measurement of capacitance voltage (CV) and drive level capacitance profiling (DLCP). Three-day sun soak was then carried out and it was observed that the fill factor recovered significantly and so did the efficiency. Experiments also showed that there was no impact of chemical erosion on the front electrode of transparent conductive oxide (TCO) films by chemicals released from the EVA films during lamination.

An opportune and unique research to evaluate the public health impact of electronic cigarettes.

PubMed

Besaratinia, Ahmad; Tommasi, Stella

2017-10-01

In response to the growing public health concern regarding the risks or benefits of electronic cigarettes (e-cig) use relative to smoking, the National Institute on Drug Abuse (NIDA) has recently introduced the first standardized- and well- characterized e-cig device to the research community (see, https://www.drugabuse.gov/funding/supplemental-information-nida-e-cig ). E-cig are promoted as safe alternatives to conventional tobacco cigarettes and/or as aides to smoking cessation. E-cig are highly popular among cigarette smokers who are unable/unwilling to quit but are willing to switch to putatively less-harmful tobacco substitutes. E-cig are also becoming increasingly popular among youth who have never experimented with combustible cigarettes. However, chemical analyses of e-cig juices (both in liquid form and after being heated into vapor) have shown that many carcinogens present in cigarette smoke are also found in a range of e-cig products. To date, the cancer-causing potential of e-cig has not been investigated in e-cig users (i.e., vapers). Use of e-cig without a prior history of smoking is currently a rare phenomenon in adults, but is increasingly common among youth. Consequently, investigating the carcinogenic potential of e-cig in nonsmoking youth provides a unique opportunity to verify the health impact of e-cig use, without the confounding effects of cigarette smoking. Within this context, the availability of the NIDA Standard Research e-cig offers a unique research opportunity with tremendous public health implications. Comparing and contrasting the cancer-causing potentials of standard vaping and smoking in youth will help determine the health risks or benefits of e-cig use relative to cigarette smoking. This information will be instrumental in making scientifically based decisions on the development and evaluation of policies and regulations on e-cig manufacture, marketing, and distribution. Ultimately, evidence-based guidelines and legislations on e-cig will help reduce the burden of tobacco-related diseases, particularly on minors and vulnerable populations.

Long term endurance test and contact degradation of CIGS solar cells

NASA Astrophysics Data System (ADS)

Ott, Thomas; Schönberger, Francillina; Walter, Thomas; Hariskos, Dimitrios; Kiowski, Oliver; Schäffler, Raymund

2013-09-01

CIGS is the most promising technology for thin-film solar cells with record efficiencies of 20.4 % on laboratory scale and 17.8 % aperture area efficiency on a 900 cm² module. Another important factor besides the cell efficiency is the reliability and long term stability of the manufactured modules, which can be assessed by accelerated ageing. In this contribution the accelerated ageing of CIGS mini modules has been investigated. Therefore, modules were dark annealed under dry heat conditions at different temperatures. During the endurance test a positive or negative bias was applied to the cells. In regular intervals the IV- and CV-characteristics were measured at room temperature. After an overall stress time of 3500 h the IV-characteristics were determined under different illumination conditions (intensity, spectral illumination). Our previous publications suggest a barrier at the back contact to explain the observed parameter drifts. This contribution is focused on the influence of different bias conditions during the endurance test on the generation of a back diode and on the change of the acceptor concentration. These parameter drifts have an impact on the open circuit voltage, fill factor and on the appearance of a cross over between dark and illuminated IV-characteristics. The interpretation of the observed parameter drifts was supported by SCAPS simulations based on the above mentioned back barrier model. As an outcome of the simulations signatures for the existence of a back barrier diode were established. IVmeasurements, temperature dependent Voc measurements and SunsVoc measurements are helpful means to detect such back diodes.

Shunt resistance and saturation current determination in CdTe and CIGS solar cells. Part 1: a new theoretical procedure and comparison with other methodologies

NASA Astrophysics Data System (ADS)

Rangel-Kuoppa, Victor-Tapio; Albor-Aguilera, María-de-Lourdes; Hérnandez-Vásquez, César; Flores-Márquez, José-Manuel; González-Trujillo, Miguel-Ángel; Contreras-Puente, Gerardo-Silverio

2018-04-01

A new proposal for the extraction of the shunt resistance (R sh ) and saturation current (I sat ) of a current-voltage (I-V) measurement of a solar cell, within the one-diode model, is given. First, the Cheung method is extended to obtain the series resistance (R s ), the ideality factor (n) and an upper limit for I sat . In this article which is Part 1 of two parts, two procedures are proposed to obtain fitting values for R sh and I sat within some voltage range. These two procedures are used in two simulated I-V curves (one in darkness and the other one under illumination) to recover the known solar cell parameters R sh , R s , n, I sat and the light current I lig and test its accuracy. The method is compared with two different common parameter extraction methods. These three procedures are used and compared in Part 2 in the I-V curves of CdS-CdTe and CIGS-CdS solar cells.

NIR emitting K2SrCl4:Eu2+, Nd3+ phosphor as a spectral converter for CIGS solar cell

NASA Astrophysics Data System (ADS)

Tawalare, P. K.; Bhatkar, V. B.; Omanwar, S. K.; Moharil, S. V.

2018-05-01

Intense near-infrared emitting phosphor K2SrCl4:Eu2+,Nd3+ with various concentrations of Nd3+ were synthesized. These are characterized with X-ray diffraction, reflectance, photoluminescence emission and photoluminescence excitation spectroscopy, PL lifetime measurements. The emission can be excited by a broad band in near ultra violet region as a consequence of Eu2+→Nd3+ energy transfer. The efficiency of Eu2+→Nd3+ energy transfer is as high as 95%. Fluorescence decay curves for Eu2+ doped samples are almost exponential and described by τ = 500 ns. Eu2+ lifetimes are shortened after Nd3+ doping. Near infrared Emission intensity is limited by Nd3+→Nd3+ energy transfer and the consequent concentration quenching. Nd3+ emission matches well with the spectral response of CIGS and CIS solar cells. Absorption of near ultra violet radiations followed by conversion to near infrared indicates the potential application in solar photovoltaics.

META-GLARE: a shell for CIG systems.

PubMed

Bottrighi, Alessio; Rubrichi, Stefania; Terenziani, Paolo

2015-01-01

In the last twenty years, many different approaches to deal with Computer-Interpretable clinical Guidelines (CIGs) have been developed, each one proposing its own representation formalism (mostly based on the Task-Network Model) execution engine. We propose META-GLARE a shell for easily defining new CIG systems. Using META-GLARE, CIG system designers can easily define their own systems (basically by defining their representation language), with a minimal programming effort. META-GLARE is thus a flexible and powerful vehicle for research about CIGs, since it supports easy and fast prototyping of new CIG systems.

Semi-transparent photovoltaic glazing based on electrodeposited CIGS solar cells on patterned molybdenum/glass substrates

NASA Astrophysics Data System (ADS)

Sidali, Tarik; Bou, Adrien; Coutancier, Damien; Chassaing, Elisabeth; Theys, Bertrand; Barakel, Damien; Garuz, Richard; Thoulon, Pierre-Yves; Lincot, Daniel

2018-03-01

In this paper, a new way of preparing semi-transparent solar cells using Cu(In1-xGax)Se2 (CIGS) chalcopyrite semiconductors as absorbers for BIPV applications is presented. The key to the elaboration process consists in the co-electrodeposition of Cu-In-Ga mixed oxides on submillimetric hole-patterned molybdenum substrate, followed by thermal reduction to metallic alloys and selenisation. This method has the advantage of being a selective deposition technique where the thin film growth is carried out only on Mo covered areas. Thus, after annealing, the transparency of the sample is always preserved, allowing light to pass through the device. A complete device (5 × 5 cm2) with 535 μm diameter holes and total glass aperture of around 35% shows an open circuit voltage (VOC) of 400 mV. Locally, the I-V curves reveal a maximum efficiency of 7.7%, VOC of 460 mV, JSC of 24 mA.cm-2 in an area of 0.1 cm2 with 35% aperture. This efficiency on the semi-transparent area is equivalent to a record efficiency of 11.9% by taking into account only the effective area.

The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system

NASA Astrophysics Data System (ADS)

Bjørk, R.; Nielsen, K. K.

2015-10-01

The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system is examined using an analytical model for four different types of commercial PVs and a commercial bismuth telluride TEG. The TEG is applied directly on the back of the PV, so that the two devices have the same temperature. The PVs considered are crystalline Si (c-Si), amorphous Si (a-Si), copper indium gallium (di)selenide (CIGS) and cadmium telluride (CdTe) cells. The degradation of PV performance with temperature is shown to dominate the increase in power produced by the TEG, due to the low efficiency of the TEG. For c-Si, CIGS and CdTe PV cells the combined system produces a lower power and has a lower efficiency than the PV alone, whereas for an a-Si cell the total system performance may be slightly increased by the TEG.

Intermixing at the absorber-buffer layer interface in thin-film solar cells: The electronic effects of point defects in Cu(In,Ga)(Se,S) 2 and Cu 2ZnSn(Se,S) 4 devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varley, J. B.; Lordi, V.

We investigate point defects in the buffer layers CdS and ZnS that may arise from intermixing with Cu(In,Ga)(S,Se) 2 (CIGS) or Cu 2ZnSn(S,Se) 4 (CZTS) absorber layers in thin-film photovoltaics. Using hybrid functional calculations, we characterize the electrical and optical behavior of Cu, In, Ga, Se, Sn, Zn, Na, and K impurities in the buffer. We find that In and Ga substituted on the cation site act as shallow donors in CdS and tend to enhance the prevailing n-type conductivity at the interface facilitated by Cd incorporation in CIGS, whereas they are deep donors in ZnS and will be lessmore » effective dopants. Substitutional In and Ga can favorably form complexes with cation vacancies (A-centers) which may contribute to the “red kink” effect observed in some CIGS-based devices. For CZTS absorbers, we find that Zn and Sn defects substituting on the buffer cation site are electrically inactive in n-type buffers and will not supplement the donor doping at the interface as in CIGS/CdS or ZnS devices. Sn may also preferentially incorporate on the S site as a deep acceptor in n-type ZnS, which suggests possible concerns with absorber-related interfacial compensation in CZTS devices with ZnS-derived buffers. Cu, Na, and K impurities are found to all have the same qualitative behavior, most favorably acting as compensating acceptors when substituting on the cation site. Lastly, our results suggest one beneficial role of K and Na incorporation in CIGS or CZTS devices is the partial passivation of vacancy-related centers in CdS and ZnS buffers, rendering them less effective interfacial hole traps and recombination centers.« less

Intermixing at the absorber-buffer layer interface in thin-film solar cells: The electronic effects of point defects in Cu(In,Ga)(Se,S){sub 2} and Cu{sub 2}ZnSn(Se,S){sub 4} devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varley, J. B.; Lordi, V.

We investigate point defects in the buffer layers CdS and ZnS that may arise from intermixing with Cu(In,Ga)(S,Se){sub 2} (CIGS) or Cu{sub 2}ZnSn(S,Se){sub 4} (CZTS) absorber layers in thin-film photovoltaics. Using hybrid functional calculations, we characterize the electrical and optical behavior of Cu, In, Ga, Se, Sn, Zn, Na, and K impurities in the buffer. We find that In and Ga substituted on the cation site act as shallow donors in CdS and tend to enhance the prevailing n-type conductivity at the interface facilitated by Cd incorporation in CIGS, whereas they are deep donors in ZnS and will be lessmore » effective dopants. Substitutional In and Ga can favorably form complexes with cation vacancies (A-centers) which may contribute to the “red kink” effect observed in some CIGS-based devices. For CZTS absorbers, we find that Zn and Sn defects substituting on the buffer cation site are electrically inactive in n-type buffers and will not supplement the donor doping at the interface as in CIGS/CdS or ZnS devices. Sn may also preferentially incorporate on the S site as a deep acceptor in n-type ZnS, which suggests possible concerns with absorber-related interfacial compensation in CZTS devices with ZnS-derived buffers. Cu, Na, and K impurities are found to all have the same qualitative behavior, most favorably acting as compensating acceptors when substituting on the cation site. Our results suggest one beneficial role of K and Na incorporation in CIGS or CZTS devices is the partial passivation of vacancy-related centers in CdS and ZnS buffers, rendering them less effective interfacial hole traps and recombination centers.« less

Intermixing at the absorber-buffer layer interface in thin-film solar cells: The electronic effects of point defects in Cu(In,Ga)(Se,S) 2 and Cu 2ZnSn(Se,S) 4 devices

DOE PAGES

Varley, J. B.; Lordi, V.

2014-08-08

We investigate point defects in the buffer layers CdS and ZnS that may arise from intermixing with Cu(In,Ga)(S,Se) 2 (CIGS) or Cu 2ZnSn(S,Se) 4 (CZTS) absorber layers in thin-film photovoltaics. Using hybrid functional calculations, we characterize the electrical and optical behavior of Cu, In, Ga, Se, Sn, Zn, Na, and K impurities in the buffer. We find that In and Ga substituted on the cation site act as shallow donors in CdS and tend to enhance the prevailing n-type conductivity at the interface facilitated by Cd incorporation in CIGS, whereas they are deep donors in ZnS and will be lessmore » effective dopants. Substitutional In and Ga can favorably form complexes with cation vacancies (A-centers) which may contribute to the “red kink” effect observed in some CIGS-based devices. For CZTS absorbers, we find that Zn and Sn defects substituting on the buffer cation site are electrically inactive in n-type buffers and will not supplement the donor doping at the interface as in CIGS/CdS or ZnS devices. Sn may also preferentially incorporate on the S site as a deep acceptor in n-type ZnS, which suggests possible concerns with absorber-related interfacial compensation in CZTS devices with ZnS-derived buffers. Cu, Na, and K impurities are found to all have the same qualitative behavior, most favorably acting as compensating acceptors when substituting on the cation site. Lastly, our results suggest one beneficial role of K and Na incorporation in CIGS or CZTS devices is the partial passivation of vacancy-related centers in CdS and ZnS buffers, rendering them less effective interfacial hole traps and recombination centers.« less

Parental Use of Electronic Cigarettes.

PubMed

Garbutt, Jane M; Miller, Whitney; Dodd, Sherry; Bobenhouse, Neil; Sterkel, Randall; Strunk, Robert C

2015-01-01

To describe parental use of electronic cigarettes (e-cigs) to better understand the safety risks posed to children. Between June 24 and November 6, 2014, parents completed a self-administered paper survey during an office visit to 15 pediatric practices in a Midwestern practice-based research network. Attitudes towards and use of e-cigs are reported for those aware of e-cigs before the survey. Ninety-five percent (628 of 658) of respondents were aware of e-cigs. Of these, 21.0% (130 of 622) had tried e-cigs at least once, and 12.3% (77) reported e-cig use by ≥1 person in their household (4.0% exclusive e-cig use, 8.3% dual use with regular cigarettes). An additional 17.3% (109) reported regular cigarette use. Most respondents from e-cig-using homes did not think e-cigs were addictive (36.9% minimally or not addictive, 25.0% did not know). While 73.7% believed that e-liquid was very dangerous for children if they ingested it, only 31.2% believed skin contact to be very dangerous. In 36.1% of e-cig-using homes, neither childproof caps nor locks were used to prevent children's access to e-liquid. Only 15.3% reported their child's pediatrician was aware of e-cig use in the home. E-cig use occurred in 1 in 8 homes, often concurrently with regular cigarettes. Many parents who used e-cigs were unaware of the potential health and safety hazards, including nicotine poisoning for children, and many did not store e-liquid safely. Pediatricians could provide education about e-cig associated safety hazards but are unaware of e-cig use in their patients' homes. Copyright © 2015 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

Shunt resistance and saturation current determination in CdTe and CIGS solar cells. Part 2: application to experimental IV measurements and comparison with other methods

NASA Astrophysics Data System (ADS)

Rangel-Kuoppa, Victor-Tapio; Albor-Aguilera, María-de-Lourdes; Hérnandez-Vásquez, César; Flores-Márquez, José-Manuel; Jiménez-Olarte, Daniel; Sastré-Hernández, Jorge; González-Trujillo, Miguel-Ángel; Contreras-Puente, Gerardo-Silverio

2018-04-01

In this Part 2 of this series of articles, the procedure proposed in Part 1, namely a new parameter extraction technique of the shunt resistance (R sh ) and saturation current (I sat ) of a current-voltage (I-V) measurement of a solar cell, within the one-diode model, is applied to CdS-CdTe and CIGS-CdS solar cells. First, the Cheung method is used to obtain the series resistance (R s ) and the ideality factor n. Afterwards, procedures A and B proposed in Part 1 are used to obtain R sh and I sat . The procedure is compared with two other commonly used procedures. Better accuracy on the simulated I-V curves used with the parameters extracted by our method is obtained. Also, the integral percentage errors from the simulated I-V curves using the method proposed in this study are one order of magnitude smaller compared with the integral percentage errors using the other two methods.

Investigating the electronic properties of Al2O3/Cu(In,Ga)Se2 interface

NASA Astrophysics Data System (ADS)

Kotipalli, R.; Vermang, B.; Joel, J.; Rajkumar, R.; Edoff, M.; Flandre, D.

2015-10-01

Atomic layer deposited (ALD) Al2O3 films on Cu(In,Ga)Se2 (CIGS) surfaces have been demonstrated to exhibit excellent surface passivation properties, which is advantageous in reducing recombination losses at the rear metal contact of CIGS thin-film solar cells. Here, we report, for the first time, experimentally extracted electronic parameters, i.e. fixed charge density (Qf) and interface-trap charge density (Dit), for as-deposited (AD) and post-deposition annealed (PDA) ALD Al2O3 films on CIGS surfaces using capacitance-voltage (C-V) and conductance-frequency (G-f) measurements. These results indicate that the AD films exhibit positive fixed charges Qf (approximately 1012 cm-2), whereas the PDA films exhibit a very high density of negative fixed charges Qf (approximately 1013 cm-2). The extracted Dit values, which reflect the extent of chemical passivation, were found to be in a similar range of order (approximately 1012 cm-2 eV-1) for both AD and PDA samples. The high density of negative Qf in the bulk of the PDA Al2O3 film exerts a strong Coulomb repulsive force on the underlying CIGS minority carriers (ns), preventing them to recombine at the CIGS/Al2O3 interface. Using experimentally extracted Qf and Dit values, SCAPS simulation results showed that the surface concentration of minority carriers (ns) in the PDA films was approximately eight-orders of magnitude lower than in the AD films. The electrical characterization and estimations presented in this letter construct a comprehensive picture of the interfacial physics involved at the Al2O3/CIGS interface.

Breakthrough to Non-Vacuum Deposition of Single-Crystal, Ultra-Thin, Homogeneous Nanoparticle Layers: A Better Alternative to Chemical Bath Deposition and Atomic Layer Deposition

PubMed Central

Liao, Yu-Kuang; Liu, Yung-Tsung; Hsieh, Dan-Hua; Shen, Tien-Lin; Hsieh, Ming-Yang; Tzou, An-Jye; Chen, Shih-Chen; Tsai, Yu-Lin; Lin, Wei-Sheng; Chan, Sheng-Wen; Shen, Yen-Ping; Cheng, Shun-Jen; Chen, Chyong-Hua; Wu, Kaung-Hsiung; Chen, Hao-Ming; Kuo, Shou-Yi; Charlton, Martin D. B.; Hsieh, Tung-Po; Kuo, Hao-Chung

2017-01-01

Most thin-film techniques require a multiple vacuum process, and cannot produce high-coverage continuous thin films with the thickness of a few nanometers on rough surfaces. We present a new ”paradigm shift” non-vacuum process to deposit high-quality, ultra-thin, single-crystal layers of coalesced sulfide nanoparticles (NPs) with controllable thickness down to a few nanometers, based on thermal decomposition. This provides high-coverage, homogeneous thickness, and large-area deposition over a rough surface, with little material loss or liquid chemical waste, and deposition rates of 10 nm/min. This technique can potentially replace conventional thin-film deposition methods, such as atomic layer deposition (ALD) and chemical bath deposition (CBD) as used by the Cu(In,Ga)Se2 (CIGS) thin-film solar cell industry for decades. We demonstrate 32% improvement of CIGS thin-film solar cell efficiency in comparison to reference devices prepared by conventional CBD deposition method by depositing the ZnS NPs buffer layer using the new process. The new ZnS NPs layer allows reduction of an intrinsic ZnO layer, which can lead to severe shunt leakage in case of a CBD buffer layer. This leads to a 65% relative efficiency increase. PMID:28383488

High throughput CIGS solar cell fabrication via ultra-thin absorber layer with optical confinement and (Cd, CBD)-free heterojunction partner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marsillac, Sylvain

2015-11-30

The main objective of this proposal was to use several pathways to reduce the production cost of Cu(In,Ga)Se 2 (CIGS) PV modules and therefore the levelized cost of energy (LCOE) associated with this technology. Three high cost drivers were identified, nominally: 1) Materials cost and availability; 2) Large scale uniformity; 3) Improved throughput These three cost drivers were targeted using the following pathways: 1) Reducing the thickness of the CIGS layer while enhancing materials quality; 2) Developing and applying enhanced in-situ metrology via real time spectroscopic ellipsometry; 3) Looking into alternative heterojunction partner, back contact and anti-reflection (AR) coating Elevenmore » main Tasks were then defined to achieve these goals (5 in Phase 1 and 6 in Phase 2), with 11 Milestones and 2 Go/No-go decision points at the end of Phase 1. The key results are summarized below« less

Carbon- and oxygen-free Cu(InGa)(SSe)₂ solar cell with a 4.63% conversion efficiency by electrostatic spray deposition.

PubMed

Yoon, Hyun; Na, Seung Heon; Choi, Jae Young; Kim, Min Woo; Kim, Hayong; An, Hee Sang; Min, Byoung Koun; Ahn, SeJin; Yun, Jae Ho; Gwak, Jihye; Yoon, KyungHoon; Kolekar, Sanjay S; van Hest, Maikel F A M; Al-Deyab, Salem S; Swihart, Mark T; Yoon, Sam S

2014-06-11

We have demonstrated the first example of carbon- and oxygen-free Cu(In,Ga)(SSe)2 (CIGSSe) absorber layers prepared by electrospraying a CuInGa (CIG) precursor followed by annealing, sulfurization, and selenization at elevated temperature. X-ray diffraction and scanning electron microscopy showed that the amorphous as-deposited (CIG) precursor film was converted into polycrystalline CIGSSe with a flat-grained morphology after post-treatment. The optimal post-treatment temperature was 300 °C for annealing and 500 °C for both sulfurization and selenization, with a ramp rate of 5 °C/min. The carbon impurities in the precursor film were removed by air annealing, and oxide that was formed during annealing was removed by sulfurization. The fabricated CIGSSe solar cell showed a conversion efficiency of 4.63% for a 0.44 cm(2) area, with Voc = 0.4 V, Jsc = 21 mA/cm(2), and FF = 0.53.

Chemical bath deposited ZnS buffer layer for Cu(In,Ga)Se2 thin film solar cell

NASA Astrophysics Data System (ADS)

Hong, Jiyeon; Lim, Donghwan; Eo, Young-Joo; Choi, Changhwan

2018-02-01

The dependence of Zn precursors using zinc sulfate (ZnSO4), zinc acetate (Zn(CH3COO)2), and zinc chloride (ZnCl2) on the characteristics of the chemical bath deposited ZnS thin film used as a buffer layer of Cu(In,Ga)Se2 (CIGS) thin film solar cell was studied. It is found that the ZnS film deposition rate increases with higher stability constant during decomplexation reaction of zinc ligands, which affects the crack formation and the amount of sulfur and oxygen contents within the film. The band gap energies of all deposited films are in the range of 3.40-3.49 eV, which is lower than that of the bulk ZnS film due to oxygen contents within the films. Among the CIGS solar cells having ZnS buffer layers prepared by different Zn precursors, the best cell efficiency with 9.4% was attained using Zn(CH3COO)2 precursor due to increased Voc mainly. This result suggests that [Zn(NH3)4]2+ complex formation should be well controlled to attain the high quality ZnS thin films.

Considerations for Solar Energy Technologies to Make Progress Towards Grid Price Parity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woodhouse, Michael; Fu, Ran; Chung, Donald

2015-11-07

In this seminar the component costs for solar photovoltaics module and system prices will be highlighted. As a basis for comparison to other renewable and traditional energy options, the metric of focus will be total lifecycle cost-of-energy (LCOE). Several innovations to traditional photovoltaics technologies (including crystalline silicon, CdTe, and CIGS) and developing technologies (including organics and perovskites) that may close the gaps in LCOE will be discussed.

Single-graded CIGS with narrow bandgap for tandem solar cells.

PubMed

Feurer, Thomas; Bissig, Benjamin; Weiss, Thomas P; Carron, Romain; Avancini, Enrico; Löckinger, Johannes; Buecheler, Stephan; Tiwari, Ayodhya N

2018-01-01

Multi-junction solar cells show the highest photovoltaic energy conversion efficiencies, but the current technologies based on wafers and epitaxial growth of multiple layers are very costly. Therefore, there is a high interest in realizing multi-junction tandem devices based on cost-effective thin film technologies. While the efficiency of such devices has been limited so far because of the rather low efficiency of semitransparent wide bandgap top cells, the recent rise of wide bandgap perovskite solar cells has inspired the development of new thin film tandem solar devices. In order to realize monolithic, and therefore current-matched thin film tandem solar cells, a bottom cell with narrow bandgap (~1 eV) and high efficiency is necessary. In this work, we present Cu(In,Ga)Se 2 with a bandgap of 1.00 eV and a maximum power conversion efficiency of 16.1%. This is achieved by implementing a gallium grading towards the back contact into a CuInSe 2 base material. We show that this modification significantly improves the open circuit voltage but does not reduce the spectral response range of these devices. Therefore, efficient cells with narrow bandgap absorbers are obtained, yielding the high current density necessary for thin film multi-junction solar cells.

Single-graded CIGS with narrow bandgap for tandem solar cells

PubMed Central

Avancini, Enrico; Buecheler, Stephan; Tiwari, Ayodhya N.

2018-01-01

Abstract Multi-junction solar cells show the highest photovoltaic energy conversion efficiencies, but the current technologies based on wafers and epitaxial growth of multiple layers are very costly. Therefore, there is a high interest in realizing multi-junction tandem devices based on cost-effective thin film technologies. While the efficiency of such devices has been limited so far because of the rather low efficiency of semitransparent wide bandgap top cells, the recent rise of wide bandgap perovskite solar cells has inspired the development of new thin film tandem solar devices. In order to realize monolithic, and therefore current-matched thin film tandem solar cells, a bottom cell with narrow bandgap (~1 eV) and high efficiency is necessary. In this work, we present Cu(In,Ga)Se2 with a bandgap of 1.00 eV and a maximum power conversion efficiency of 16.1%. This is achieved by implementing a gallium grading towards the back contact into a CuInSe2 base material. We show that this modification significantly improves the open circuit voltage but does not reduce the spectral response range of these devices. Therefore, efficient cells with narrow bandgap absorbers are obtained, yielding the high current density necessary for thin film multi-junction solar cells. PMID:29707066

Bandgap profiling in CIGS solar cells via valence electron energy-loss spectroscopy

NASA Astrophysics Data System (ADS)

Deitz, Julia I.; Karki, Shankar; Marsillac, Sylvain X.; Grassman, Tyler J.; McComb, David W.

2018-03-01

A robust, reproducible method for the extraction of relative bandgap trends from scanning transmission electron microscopy (STEM) based electron energy-loss spectroscopy (EELS) is described. The effectiveness of the approach is demonstrated by profiling the bandgap through a CuIn1-xGaxSe2 solar cell that possesses intentional Ga/(In + Ga) composition variation. The EELS-determined bandgap profile is compared to the nominal profile calculated from compositional data collected via STEM-based energy dispersive X-ray spectroscopy. The EELS based profile is found to closely track the calculated bandgap trends, with only a small, fixed offset difference. This method, which is particularly advantageous for relatively narrow bandgap materials and/or STEM systems with modest resolution capabilities (i.e., >100 meV), compromises absolute accuracy to provide a straightforward route for the correlation of local electronic structure trends with nanoscale chemical and physical structure/microstructure within semiconductor materials and devices.

Growth and characterization of epitaxial silver indium diselenide

NASA Astrophysics Data System (ADS)

Pena Martin, Pamela

Photovoltaics (solar cells) are a key player in the renewable energy frontier, and will become increasingly important as their cost per watt continues to drop, especially if fossil fuel costs increase. One particularly promising photovoltaic technology is based on chalcopyrite-structure semiconductors. Within the chalcopyrite compounds the highest efficiency thin film solar cell absorber material to date is Cu(In,Ga)Se2 (CIGS). While current efficiency records are over 21% for single-junction cells, there is still room for improvement. Replacing some of the Cu with Ag has been shown to be beneficial in CIGS devices. However, the Ag- containing chalcopyrites are still relatively unknown in terms of their growth mechanism, energetics, and surface atomic and electronic properties. These are best inferred through study of epitaxial films, yet they have little mention in literature and have not been the subject of a detailed study. This work describes the growth of epitaxial AgInSe2 (AIS) on GaAs substrates, studying the morphology, structure, and surface properties to understand how growth takes place. It also seeks to experimentally determine the surface electronic and atomic structure at the atomic scale to gain insight into the part of the material that forms the heterojunction that collects photon energy in the device. Finally, this work seeks to compare and contrast these findings with what is known about CIGS to determine where similarities and, more importantly, the differences may lie. This study has found that single phase tetragonal AIS can be epitaxially grown on GaAs, as illustrated by x-ray diffraction (XRD), transmission electron microscope (TEM), and surface morphology data. Like CIGS, the close packed polar (112) planes have the lowest energy. The morphology points to a difference in step dynamics, leading to less faceted, straight edged island shapes compared to CIGS. Epitaxial temperature as a function of growth direction shows a different trend in AIS than in CIGS. Interdiffusion of the group III elements across the substrate interface was found to result in an epitaxial intermixed layer between the film and substrate in some cases, which may help mediate the lattice mismatch. At the atomic scale, scanning tunneling microscopy (STM) was used to observe details of the surface morphology, which indicated growth of the (112)A orientation of AIS by a screw dislocation mechanism (other surfaces were not examined by STM but are expected to show similar results). The surface atomic structure was directly imaged for the first time, revealing an arrangement similar to that expected from a bulk terminated surface. The electronic structure shows a gap in surface electronic states with a width comparable to bulk AIS, n-type conduction, and a tail of states near the valence band edge that decay well into the gap. The conduction and valence bands show fluctuations as a function of position on the surface, with greater magnitude in the valence band. The fluctuations in both bands are less than those observed on the surface of CIS by STM. It seems to indicate a reduction in band tails, both in magnitude and spacial extent, in AIS compared to CIS, likely tied to a reduction in point defect concentration at the surface.

Immunological and toxicological risk assessment of e-cigarettes.

PubMed

Kaur, Gagandeep; Pinkston, Rakeysha; Mclemore, Benathel; Dorsey, Waneene C; Batra, Sanjay

2018-03-31

Knowledge of the long-term toxicological and immunological effects of e-cigarette (e-cig) aerosols remains elusive due to the relatively short existence of vaping. Therefore, we performed a systematic search of articles published in public databases and analysed the research evidence in order to provide critical information regarding e-cig safety. Electronic nicotine delivery systems (or e-cigs) are an alternative to traditional cigarettes for the delivery of nicotine and are typically filled with glycerol or propylene glycol-based solutions known as e-liquids. Though present in lower quantities, e-cig aerosols are known to contain many of the harmful chemicals found in tobacco smoke. However, due to the paucity of experimental data and contradictory evidence, it is difficult to draw conclusive outcomes regarding toxicological, immunological and clinical impacts of e-cig aerosols. Excessive vaping has been reported to induce inflammatory responses including mitogen-activated protein kinase, Janus tyrosine kinase/signal transducer and activator of transcription and nuclear factor-κB signalling, similar to that induced by tobacco smoke. Based on recent evidence, prolonged exposure to some constituents of e-cig aerosols might result in respiratory complications such as asthma, chronic obstructive pulmonary disease and inflammation. Future studies are warranted that focus on establishing correlations between e-cig types, generations and e-liquid flavours and immunological and toxicological profiles to broaden our understanding about the effects of vaping. Copyright ©ERS 2018.

Thin Film Photovoltaic Partnership Project | Photovoltaic Research | NREL

Science.gov Websites

Thin Film Photovoltaic Partnership Project Thin Film Photovoltaic Partnership Project NREL's Thin Film Photovoltaic (PV) Partnership Project led R&D on emerging thin-film solar technologies in the National Laboratory developed low-cost transparent encapsulation schemes for CIGS cells that reduced power

Effects of sodium and potassium on the photovoltaic performance of CIGS solar cells

DOE PAGES

Raguse, John M.; Muzzillo, Christopher P.; Sites, James R.; ...

2016-11-17

Here, the deliberate introduction of K and Na into Cu(In, Ga)Se 2 (CIGS) absorbers was investigated by varying a combination of an SiO 2 diffusion barrier, coevaporation of KF with the CIGS absorber, and a KF postdeposition treatment (PDT). Devices made with no diffusion barrier and KF coevaporation treatment exhibited the highest photovoltaic conversion efficiency with the smallest overall distribution in key current density-voltage (J-V) performance metrics. Out-diffusion of Na and K from the substrate, KF coevaporation, and KF PDT all increased carrier concentration, open-circuit voltage, fill factor, and power conversion efficiency. Quantum-efficiency analysis of devices highlighted the greatest lossmore » in the short-circuit current density due to incomplete absorption and collection. Secondary ion mass spectrometry illustrated the efficacy of the SiO 2 film as a sodium and potassium diffusion barrier, as well as their relative concentration in the absorber. Introduction of KF appeared to enhance diffusion of Na from the substrate, in agreement with previous studies.« less

Photovoltaic materials and devices 2016

DOE PAGES

Sopori, Bhushan; Basnyat, Prakash; Mehta, Vishal

2016-01-01

Photovoltaic energy continues to grow with about 59 GW of solar PV installed in 2015. While most of the PV production (about 93%) was Si wafer based, both CdTe and CI(G)S are growing in their shares. There is also continued progress at the laboratory scale in OPV and dye sensitized solar cells. As the market grows, emphasis on reducing the cost of modules and systems continues to grow. This is the fourth special issue of this journal that is dedicated to gathering selected papers on recent advances in materials, devices, and modules/PV systems. This issue contains sixteen papers on variousmore » aspects of photovoltaics. As a result, these fall in four broad categories of novel materials, device design and fabrication, modules, and systems.« less

Cu doping concentration effect on the physical properties of CdS thin films obtained by the CBD technique

NASA Astrophysics Data System (ADS)

Albor Aguilera, M. L.; Flores Márquez, J. M.; Remolina Millan, A.; Matsumoto Kuwabara, Y.; González Trujillo, M. A.; Hernández Vásquez, C.; Aguilar Hernandez, J. R.; Hernández Pérez, M. A.; Courel-Piedrahita, M.; Madeira, H. T. Yee

2017-08-01

Cu(In, Ga)Se2 (CIGS) and Cu2ZnSnS4 (CZTS) semiconductors are direct band gap materials; when these types of material are used in solar cells, they provide efficiencies of 22.1% and 12.6%, respectively. Most traditional fabrication methods involve expensive vacuum processes including co-evaporation and sputtering techniques, where films and doping are conducted separately. On the other hand, the chemical bath deposition (CBD) technique allows an in situ process. Cu-doped CdS thin films working as a buffer layer on solar cells provide good performing devices and they may be deposited by low cost techniques such as chemical methods. In this work, Cu-doped CdS thin films were deposited using the CBD technique on SnO2:F (FTO) substrates. The elemental analysis and mapping reconstruction were conducted by EDXS. Morphological, optical and electrical properties were studied, and they revealed that Cu doping modified the CdS structure, band-gap value and the electrical properties. Cu-doped CdS films show high resistivity compared to the non-doped CdS. The appropriate parameters of Cu-doped CdS films were determined to obtain an adequate window or buffer layer on CIGS and CZTS photovoltaic solar cells.

Cation Substitution in Earth-Abundant Kesterite Photovoltaic Materials.

PubMed

Li, Jianjun; Wang, Dongxiao; Li, Xiuling; Zeng, Yu; Zhang, Yi

2018-04-01

As a promising candidate for low-cost and environmentally friendly thin-film photovoltaics, the emerging kesterite-based Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells have experienced rapid advances over the past decade. However, the record efficiency of CZTSSe solar cells (12.6%) is still significantly lower than those of its predecessors Cu(In,Ga)Se 2 (CIGS) and CdTe thin-film solar cells. This record has remained for several years. The main obstacle for this stagnation is unanimously attributed to the large open-circuit voltage ( V OC ) deficit. In addition to cation disordering and the associated band tailing, unpassivated interface defects and undesirable energy band alignment are two other culprits that account for the large V OC deficit in kesterite solar cells. To capture the great potential of kesterite solar cells as prospective earth-abundant photovoltaic technology, current research focuses on cation substitution for CZTSSe-based materials. The aim here is to examine recent efforts to overcome the V OC limit of kesterite solar cells by cation substitution and to further illuminate several emerging prospective strategies, including: i) suppressing the cation disordering by distant isoelectronic cation substitution, ii) optimizing the junction band alignment and constructing a graded bandgap in absorber, and iii) engineering the interface defects and enhancing the junction band bending.

Cation Substitution in Earth‐Abundant Kesterite Photovoltaic Materials

PubMed Central

Li, Jianjun; Wang, Dongxiao; Li, Xiuling; Zeng, Yu

2018-01-01

Abstract As a promising candidate for low‐cost and environmentally friendly thin‐film photovoltaics, the emerging kesterite‐based Cu2ZnSn(S,Se)4 (CZTSSe) solar cells have experienced rapid advances over the past decade. However, the record efficiency of CZTSSe solar cells (12.6%) is still significantly lower than those of its predecessors Cu(In,Ga)Se2 (CIGS) and CdTe thin‐film solar cells. This record has remained for several years. The main obstacle for this stagnation is unanimously attributed to the large open‐circuit voltage (V OC) deficit. In addition to cation disordering and the associated band tailing, unpassivated interface defects and undesirable energy band alignment are two other culprits that account for the large V OC deficit in kesterite solar cells. To capture the great potential of kesterite solar cells as prospective earth‐abundant photovoltaic technology, current research focuses on cation substitution for CZTSSe‐based materials. The aim here is to examine recent efforts to overcome the V OC limit of kesterite solar cells by cation substitution and to further illuminate several emerging prospective strategies, including: i) suppressing the cation disordering by distant isoelectronic cation substitution, ii) optimizing the junction band alignment and constructing a graded bandgap in absorber, and iii) engineering the interface defects and enhancing the junction band bending. PMID:29721421

Implications for current regulatory waste toxicity characterisation methods from analysing metal and metalloid leaching from photovoltaic modules

NASA Astrophysics Data System (ADS)

Collins, Mary Kayla; Anctil, Annick

2017-07-01

The appropriateness of regulatory methods to characterise the toxicity of photovoltaic (PV) modules was investigated to quantify potential environmental impacts for modules disposed of in landfills. Because solar energy is perceived as a green technology, it is important to ensure that end-of-life issues will not be detrimental to solar energy's success. United States Environmental Protection Agency Method 1311, California waste extraction test, and modified versions of both were performed on a multi-crystalline silicon module and cells and a copper indium gallium diselenide (CIGS) module. Variations in metal leachate concentrations were found with changes in testing parameters. Lead concentrations from the multi-crystalline module ranged from 16.2 to 50.2 mg/L. Cadmium concentrations from the CIGS module ranged from 0.1 to 3.52 mg/L. This raises doubt that regulatory methods can adequately characterise PV modules. The results are useful for developing end-of-life procedures, which is a positive step towards avoiding an e-waste problem and continuing trends of increasing installation and cost reduction in the PV market.

Perceptions and use of electronic cigarettes in pregnancy

PubMed Central

McCubbin, Andrea; Fallin-Bennett, Amanda; Barnett, Janine; Ashford, Kristin

2017-01-01

Abstract Use of electronic cigarettes (e-cigs) is quickly growing in the United States, despite the unknown health implications and unregulated device contents. Although research is emerging around e-cigs in general, there continues to be a lack of scientific evidence regarding the safety and risks of e-cig use on maternal and fetal health, even though adverse health effects of nicotine on maternal and fetal outcomes are documented. This review summarizes existing perceptions of e-cig use in pregnancy, based on the limited number of publications available, and highlights the necessity of conducting additional research in this field of public health. Authors conducted a literature search of scientific peer-reviewed articles published from January 2006 to October 2016, comprising more than a decade of research. Search keywords include ‘tobacco use’, ‘electronic cigarette(s)’ and ‘pregnancy’. Fifty-seven publications were identified, narrowed to fifteen by screening title/abstract for potential relevance, with seven articles chosen for final inclusion. Of these seven studies, most participants not only believed e-cigs pose risks to maternal and child health but also perceived e-cigs as a safer and potentially healthier alternative to traditional cigarettes, and may assist with smoking cessation. Further research is needed to determine health implications and provide clinical guidelines for e-cig use in pregnancy. PMID:28158490

The influence of different locations of sputter guns on the morphological and structural properties of Cu-In-Ga precursors and Cu(In,Ga)Se2 thin films

NASA Astrophysics Data System (ADS)

Wang, J.; Zhu, J.; He, Y. X.

2014-01-01

The influence of two different locations of sputter guns on the morphological and structural properties of Cu-In-Ga precursors and Cu(In,Ga)Se2 (CIGS) thin films was investigated. All the precursors contained cauliflower-like nodules, whereas smaller subnodules were observed on the background. All the precursors revealed apparent three-layered structures, and voids were observed at the CIGS/SLG interface of Sets 1 and 2 films rather than Set 3 film. EDS results indicated that all CIGS thin films were Cu-deficient. Based on the grazing incidence X-ray diffraction (GIXRD) patterns, as-selenized films showed peaks corresponding to the chalcopyrite-type CIGS structure. Depth-resolved Raman spectra showed the formation of a dominant CIGS phase inside the films for all the as-selenized samples investigated, and of an ordered vacancy compound (OVC) phase like Cu(In,Ga)3Se5 or Cu(In,Ga)2Se3.5 at the surface and/or CIGS/SLG interface region of Sets 2 and 3 films. No evidence was obtained on the presence of an OVC phase in Set 1 CIGS film, which may be speculated that long-time annealing is contributed to suppress the growth of OVC phases. The results of the present work suggest that the metallic precursors deposited with the upright-location sputter gun might be more appropriate to prepare CIGS thin films than those sputtered with the titled-location gun.

Nanoengineered CIGS thin films for low cost photovoltaics

NASA Astrophysics Data System (ADS)

Eldada, Louay; Taylor, Matthew; Sang, Baosheng; McWilliams, Scott; Oswald, Robert; Stanbery, Billy J.

2008-08-01

Low cost manufacturing of Cu(In,Ga)Se2 (CIGS) films for high efficiency photovoltaic devices by the innovative Field-Assisted Simultaneous Synthesis and Transfer (FASST®) process is reported. The FASST® process is a two-stage reactive transfer printing method relying on chemical reaction between two separate precursor films to form CIGS, one deposited on the substrate and the other on a printing plate in the first stage. In the second stage these precursors are brought into intimate contact and rapidly reacted under pressure in the presence of an applied electrostatic field. The method utilizes physical mechanisms characteristic of anodic wafer bonding and rapid thermal annealing, effectively creating a sealed micro-reactor that ensures high material utilization efficiency, direct control of reaction pressure, and low thermal budget. The use of two independent ink-based or PVD-based nanoengineered precursor thin films provides the benefits of independent composition and flexible deposition technique optimization, and eliminates pre-reaction prior to the second stage FASST® synthesis of CIGS. High quality CIGS with large grains on the order of several microns are formed in just several minutes based on compositional and structural analysis by XRF, SIMS, SEM and XRD. Cell efficiencies of 12.2% have been achieved using this method.

Optical properties of ultrathin CIGS films studied by spectroscopic ellipsometry assisted by chemical engineering

NASA Astrophysics Data System (ADS)

Loubat, Anaïs; Eypert, Céline; Mollica, Fabien; Bouttemy, Muriel; Naghavi, Negar; Lincot, Daniel; Etcheberry, Arnaud

2017-11-01

CIGS (Cu(In1-x,Gax)Se2) based devices are very efficient for photovoltaic conversion. A non-destructive optical study of CIGS is an important challenge as for evaluation of the material quality, and for device modeling. Spectroscopic Ellipsometry (SE) is well adapted for a quantitative characterization only if the handicaps of the roughness limitation, the oxidized surface, or the compositional gradient are minimized. For this SE study, ungraded and thin CIGS samples are prepared with GGI (x) ratio (=[Ga]/([Ga] + [In])) ranging from 0.15 to 0.60. Thanks to chemical engineering based on acidic bromine solution etching and/or HCl de-oxidation, the SE experiments are performed on flattened surfaces, and also, on as grown de-oxidized samples. Using assumptions based on XPS, AFM and SEM complementary characterizations, we give proof of oxide free flattening surfaces and chemical homogeneity in depth. Using these observations, the SE data are modeled on the basis of a three layer model using an Adachi/Tauc-Lorentz formula for the CIGS dispersion. The optical gap values are determined in good agreement with the x ratio measured by the other characterization techniques. SE is able to well estimate the thickness and roughness variations on each sample. Furthermore, the CIGS optical constant extracted on such reference flat surfaces are then applied to the as grown-de-oxidized surfaces, enabling to describe the SE data obtained on rougher surfaces. A complete consistency of the proposed model is shown as well as the capability of SE to be sensitive to the chemistry of the surface.

Thin-Film Solar Cells on Metal Foil Substrates for Space Power

NASA Technical Reports Server (NTRS)

Raffaelle, Ryne P.; Hepp, Aloysius F.; Hoffman, David J.; Dhere, N.; Tuttle, J. R.; Jin, Michael H.

2004-01-01

Photovoltaic arrays have played a key role in power generation in space. The current technology will continue to evolve but is limited in the important mass specific power metric (MSP or power/weight ratio) because it is based on bulk crystal technology. The objective of this research is to continue development of an innovative photovoltaic technology for satellite power sources that could provide up to an order of magnitude saving in both weight and cost, and is inherently radiation-tolerant through use of thin film technology and thin foil substrates such as 5-mil thick stainless steel foil or 1-mil thick Ti. Current single crystal technology for space power can cost more than $300 per watt at the array level and weigh more than 1 kg/sq m equivalent to specific power of approx. 65 W/kg. Thin film material such as CuIn(1-x),Ga(x)S2, (CIGS2), CuIn(1-x), G(x)Se(2-y),S(y), (CIGSS) or amorphous hydrogenated silicon (a-Si:H) may be able to reduce both the cost and mass per unit area by an order of magnitude. Manufacturing costs for solar arrays are an important consideration for total spacecraft budget. For a medium sized 5kW satellite, for example, the array manufacturing cost alone may exceed $2 million. Moving to thin film technology could reduce this expense to less than $500 K. Previous work at FSEC demonstrated the potential of achieving higher efficiencies from CIGSS thin film solar cells on 5-mil thick stainless steel foil as well as initial stages of facility augmentation for depositing thin film solar cells on larger (6"x 4") substrates. This paper presents further progress in processing on metal foil substrates. Also, previous work at DayStar demonstrated the feasibility of flexible-thin-film copper-indium-gallium-diselenide (CIGS) solar cells with a power-to-weight ratio in excess of 1000 W/kg. We will comment on progress on the critical issue of scale-up of the solar cell absorber deposition process. Several important technical issues need to be resolved to realize the benefits of lightweight technologies for solar arrays, such as: monolithic interconnects, lightweight array structures, and new ultra-light support and deployment mechanisms. Once the technology has gained spaceflight certification it should find rapid acceptance in specific satellite markets.

Facile Growth of Cu2ZnSnS4 Thin-Film by One-Step Pulsed Hybrid Electrophoretic and Electroplating Deposition.

PubMed

Tsai, Hung-Wei; Chen, Chia-Wei; Thomas, Stuart R; Hsu, Cheng-Hung; Tsai, Wen-Chi; Chen, Yu-Ze; Wang, Yi-Chung; Wang, Zhiming M; Hong, Hwen-Fen; Chueh, Yu-Lun

2016-02-23

The use of costly and rare metals such as indium and gallium in Cu(In,Ga)Se2 (CIGS) based solar cells has motivated research into the use of Cu2ZnSnS4 (CZTS) as a suitable replacement due to its non-toxicity, abundance of compositional elements and excellent optical properties (1.5 eV direct band gap and absorption coefficient of ~10(4) cm(-1)). In this study, we demonstrate a one-step pulsed hybrid electrodeposition method (PHED), which combines electrophoretic and electroplating deposition to deposit uniform CZTS thin-films. Through careful analysis and optimization, we are able to demonstrate CZTS solar cells with the VOC, JSC, FF and η of 350 mV, 3.90 mA/cm(2), 0.43 and 0.59%, respectively.

ZnS thin films deposition by thermal evaporation for photovoltaic applications

NASA Astrophysics Data System (ADS)

Benyahia, K.; Benhaya, A.; Aida, M. S.

2015-10-01

ZnS thin films were deposited on glass substrates by thermal evaporation from millimetric crystals of ZnS. The structural, compositional and optical properties of the films are studied by X-ray diffraction, SEM microscopy, and UV-VIS spectroscopy. The obtained results show that the films are pin hole free and have a cubic zinc blend structure with (111) preferential orientation. The estimated optical band gap is 3.5 eV and the refractive index in the visible wavelength ranges from 2.5 to 1.8. The good cubic structure obtained for thin layers enabled us to conclude that the prepared ZnS films may have application as buffer layer in replacement of the harmful CdS in CIGS thin film solar cells or as an antireflection coating in silicon-based solar cells.

The Theory of Planned Behavior and E-cig Use: Impulsive Personality, E-cig Attitudes, and E-cig Use.

PubMed

Hershberger, Alexandra; Connors, Miranda; Um, Miji; Cyders, Melissa A

2018-04-01

The current paper applied the Theory of Planned Behavior (TPB; Ajzen & Fishbein, 1988) to understand how impulsive personality traits and attitudes concerning e-cig use relate to the likelihood of electronic cigarette (e-cig) use. Seven hundred and fourteen participants (Mean age = 34.04, SD = 10.89, 48.6% female) completed cross-sectional measures of e-cig use attitudes (CEAC) and the Short UPPS-P Impulsive Behavior Scale. A structural path analysis suggested that urgency and deficits in conscientiousness were significantly related to e-cig attitudes (CFI = 0.99, TLI = 0.99, RMSEA = 0.02; urgency: β = 0.32, p = .001; deficits in conscientiousness: β = -0.48, p < .001). E-cig attitude scores were significantly higher for e-cig users than non-users, β = 0.85, p < .001. There was no significant direct path from impulsive personality traits to e-cig use. Findings provide initial support for a model in which impulsive traits are related to e-cig use through positive e-cig attitudes.

Integrated, Flexible, High-efficiency Solar Cells: Epitaxial Lift-Off GaAs Solar Cells and Enabling Substrate Reuse

DTIC Science & Technology

2012-08-01

substrate cells. 3   GaAs CIGS CdTe α-SI Organic Trip. jun. Metam. C-Si Trip. Jun. Ge sub InP Power/Weight  Tradeoff...40   -  AR  coa<ng  ( ZnS /MgF2)150nm...AR  coa<ng  ( ZnS /MgF2)150nm                                      $5   -  HF

Factors associated with experimentation of electronic cigarettes among Parisian teenagers in 2013.

PubMed

Dautzenberg, Bertrand; Berlin, Ivan; Tanguy, Marie-Laure; Rieu, Nicole; Birkui, Pierre

2015-01-01

Electronic cigarettes (e-cig.) became widely used among adults. Data are insufficient about e-cig. experimentation among youth. To assess prevalence of e-cig. experimentation and associated factors among the 12 to 19 years old we analyse a cross sectional school based survey in the city of Paris, France in 2013 on a randomly selected sample of 2 % of schoolchildren (n = 3 279). Self-report questionnaire include demographic, individual and family smoking characteristics and questions about e-cig: "Have you ever used an e-cigarette?"- "Did you use e-cigarette in the last 30 days?"-"Did you try e-cigarette as a first tobacco product?". In 2013, 17.9 % (564) schoolchildren reported having experienced the e-cig (boys: 19.0 %, girls: 16.8 %) compared to 9.8 % in 2012. Experimentation rate increases from 5 % among the 12 to 30 % among the 16-year-old. E-cig. experimentation was significantly associated with 11 parameters including : age >15 years (OR: 0.66 (IC95 % = 0.46-0.94)); smoking 10 cigarettes or more (OR = 5.67 (IC95 % = 3.11-10.34)), best friends and siblings smoker (OR = 1.54 (IC95 % = 1.11-2.14)) and (OR = 1.88 (IC95 % = 1.41-2.52)); experimentation of shisha (OR = 2.60 (IC95 % = 1.75-3.86)), cannabis use (OR = 1.90 (IC95 % = 1.32-2.72)); having two parents who forbid smoking (OR = 2.32 (IC95 % = 1.63-3.30)). Only 5.6 % of the study population (and 32.5 % of e-cig. experimenters (183/564)) have used it in the last 30 days; 1.7 % of the study population and 10.0 % of e-cig. experimenters were non-smokers (56/564). Rate of e-cig. experimentation among schoolchildren increased by 8.1 % in 1 year. Non-smoking youth may use e-cig. Prospective studies are urgently needed to assess the evolution of e-cig. use both among smoking and non-smoking youth.

Slow-muon study of quaternary solar-cell materials: Single layers and p -n junctions

NASA Astrophysics Data System (ADS)

Alberto, H. V.; Vilão, R. C.; Vieira, R. B. L.; Gil, J. M.; Weidinger, A.; Sousa, M. G.; Teixeira, J. P.; da Cunha, A. F.; Leitão, J. P.; Salomé, P. M. P.; Fernandes, P. A.; Törndahl, T.; Prokscha, T.; Suter, A.; Salman, Z.

2018-02-01

Thin films and p -n junctions for solar cells based on the absorber materials Cu (In ,G a ) Se2 and Cu2ZnSnS4 were investigated as a function of depth using implanted low energy muons. The most significant result is a clear decrease of the formation probability of the Mu+ state at the heterojunction interface as well as at the surface of the Cu (In ,G a ) Se2 film. This reduction is attributed to a reduced bonding reaction of the muon in the absorber defect layer at its surface. In addition, the activation energies for the conversion from a muon in an atomiclike configuration to a anion-bound position are determined from temperature-dependence measurements. It is concluded that the muon probe provides a measurement of the effective surface defect layer width, both at the heterojunctions and at the films. The CIGS surface defect layer is crucial for solar-cell electrical performance and additional information can be used for further optimizations of the surface.

Solution-Processed Ag Nanowires + PEDOT:PSS Hybrid Electrode for Cu(In,Ga)Se₂ Thin-Film Solar Cells.

PubMed

Shin, Donghyeop; Kim, Taegeon; Ahn, Byung Tae; Han, Seung Min

2015-06-24

To reduce the cost of the Cu(In,Ga)Se2 (CIGS) solar cells while maximizing the efficiency, we report the use of an Ag nanowires (NWs) + poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) ( PSS) hybrid transparent electrode, which was deposited using all-solution-processed, low-cost, scalable methods. This is the first demonstration of an Ag NWs + PSS transparent electrode applied to CIGS solar cells. The spin-coated 10-nm-thick PSS conducting polymer layer in our hybrid electrode functioned as a filler of empty space of an electrostatically sprayed Ag NW network. Coating of PSS on the Ag NW network resulted in an increase in the short-circuit current from 15.4 to 26.5 mA/cm(2), but the open-circuit voltage and shunt resistance still needed to be improved. The limited open-circuit voltage was found to be due to interfacial recombination that is due to the ineffective hole-blocking ability of the CdS film. To suppress the interfacial recombination between Ag NWs and the CdS film, a Zn(S,O,OH) film was introduced as a hole-blocking layer between the CdS film and Ag NW network. The open-circuit voltage of the cell sharply improved from 0.35 to 0.6 V, which resulted in the best cell efficiency of 11.6%.

Novel in situ resistance measurement for the investigation of CIGS growth in a selenization process

NASA Astrophysics Data System (ADS)

Liu, Wei; Tian, Jian-Guo; Li, Zu-Bin; He, Qing; Li, Feng-Yan; Li, Chang-Jian; Sun, Yun

2009-03-01

During the selenization process of CIGS thin films, the relation between the element loss rate and the precursor depositions are analyzed. The growth of the CIGS thin films during the selenization process is investigated by the novel in situ resistance measurement, by which the formation of compound semiconductors can be observed directly and simultaneously. Their structures, phase evolutions and element losses are analyzed by XRD and XRF. Based on the experimental results, it can be concluded that the phase transforms have nothing to do with the deposition sequences of precursors, while the element loss rates are related to the deposition sequences in this process. In addition, element loss mechanisms of CIGS thin films prepared by the selenization process are analyzed by the phase evolutions and chemical combined path in the In, Ga-Se reaction processes. Moreover it is verified that the element losses are depressed by increasing the ramping-up rate finally. The results provide effective methods to fabricate high-quality CIGS thin films with low element losses.

In-situ X-ray Nanocharacterization of Defect Kinetics in Chalcogenide Solar Cell Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bertoni, Mariana; Lai, Barry; Masser, Jorg

2016-09-21

For decades the optimization of polycrystalline absorbers has been done using an Edisonian approach, where trial and error and complex design of experiments in large parameter spaces have driven efficiencies to the record values we see today – CIGS at 22.5%, 22.1% for CdTe, 21.3% for high purity multi-crystalline silicon. Appropriate growth parameters are critical to ensure good quality crystals with low concentration of structural defects - low dislocation density and large grain sizes. However, to bridge the gap between the efficiencies today and the fundamental Shockley-Queisser limit for these materials a much more fundamental understanding of the role andmore » interaction between composition, structure, defect density and electrical properties is required. In recent years multiple novel characterization techniques have shown the potential that nanoscale characterization can have in deciphering the composition of grain boundaries in materials like CIGS and CdTe. However, high resolution has come at the cost of small sampling areas and number of specimens, making it extremely difficult to draw conclusions based on the characteristic small sampling sizes. The missing links thus far have been: (1) the lack of statistical meaningfulness of the nanosclae studies and (2) the direct correlation of compositional variations to electrical performance with nanoscale resolution. In this work we present the use of synchrotron-based nano-X-ray fluorescence microscopy (nano-XRF), x-ray absorption nanospectroscopy (nano-XAS) coupled with nano-x-ray beam induced current (nano-XBIC) as ideal tools for investigating elemental, chemical and electrical properties of large areas of solar cell materials at the sub-micron scale with very high sensitivity. We show how the technique can provide statistical valuable information regarding the elemental segregation in CIGS and the direct correlation to current collection. For example, we demonstrate that Cu and Ga (and with that, CGI and GGI) correlate positively, and In negatively with charge collection efficiency for cells with low Ga content, both at grain boundaries and in grain cores. For cells with high Ga content, the charge collection efficiency depends to much lesser extent on the elemental distribution. The objective is three folded: (1) develop an x-ray in-situ microscopy capability to simulate growth and processing conditions, (2) apply it to elucidate performance-governing defect kinetics in chalcogenide solar cell materials, and (3) to study approaches to engineer materials from the nanoscale up. The development of these capabilities will enable experimental characterization to take place under actual processing and operating conditions and it will have impact well beyond the proposed research, enabling future studies on a large variety of materials system where electronic properties depend on underlying structural or chemical inhomogeneities.« less

Loss mechanisms in hydrazine-processed Cu2ZnSn(Se,S)4 solar cells

NASA Astrophysics Data System (ADS)

Gunawan, Oki; Todorov, Teodor K.; Mitzi, David B.

2010-12-01

We present a device characterization study for hydrazine-processed kesterite Cu2ZnSn(Se,S)4 (CZTSSe) solar cells with a focus on pinpointing the main loss mechanisms limiting device efficiency. Temperature-dependent study and time-resolved photoluminescence spectroscopy on these cells, in comparison to analogous studies on a reference Cu(In,Ga)(Se,S)2 (CIGS) cell, reveal strong recombination loss at the CZTSSe/CdS interface, very low minority-carrier lifetimes, and high series resistance that diverges at low temperature. These findings help identify the key areas for improvement of these CZTSSe cells in the quest for a high-performance indium- and tellurium-free solar cell.

Exposure to Electronic Cigarettes Impairs Pulmonary Anti-Bacterial and Anti-Viral Defenses in a Mouse Model

PubMed Central

Sussan, Thomas E.; Gajghate, Sachin; Thimmulappa, Rajesh K.; Ma, Jinfang; Kim, Jung-Hyun; Sudini, Kuladeep; Consolini, Nicola; Cormier, Stephania A.; Lomnicki, Slawo; Hasan, Farhana; Pekosz, Andrew; Biswal, Shyam

2015-01-01

Electronic cigarettes (E-cigs) have experienced sharp increases in popularity over the past five years due to many factors, including aggressive marketing, increased restrictions on conventional cigarettes, and a perception that E-cigs are healthy alternatives to cigarettes. Despite this perception, studies on health effects in humans are extremely limited and in vivo animal models have not been generated. Presently, we determined that E-cig vapor contains 7x1011 free radicals per puff. To determine whether E-cig exposure impacts pulmonary responses in mice, we developed an inhalation chamber for E-cig exposure. Mice that were exposed to E-cig vapor contained serum cotinine concentrations that are comparable to human E-cig users. E-cig exposure for 2 weeks produced a significant increase in oxidative stress and moderate macrophage-mediated inflammation. Since, COPD patients are susceptible to bacterial and viral infections, we tested effects of E-cigs on immune response. Mice that were exposed to E-cig vapor showed significantly impaired pulmonary bacterial clearance, compared to air-exposed mice, following an intranasal infection with Streptococcus pneumonia. This defective bacterial clearance was partially due to reduced phagocytosis by alveolar macrophages from E-cig exposed mice. In response to Influenza A virus infection, E-cig exposed mice displayed increased lung viral titers and enhanced virus-induced illness and mortality. In summary, this study reports a murine model of E-cig exposure and demonstrates that E-cig exposure elicits impaired pulmonary anti-microbial defenses. Hence, E-cig exposure as an alternative to cigarette smoking must be rigorously tested in users for their effects on immune response and susceptibility to bacterial and viral infections. PMID:25651083

Knowledge on Irradiation, Medical Imaging Prescriptions, and Clinical Imaging Referral Guidelines among Physicians in a Sub-Saharan African Country (Cameroon)

PubMed Central

Tene, Ulrich; Samba Ngano, Odette; Tchemtchoua Youta, Justine; Simo, Augustin; Gonsu Fotsin, Joseph

2017-01-01

Background Clinical imaging guidelines (CIGs) are suitable tools to enhance justification of imaging procedures. Objective To assess physicians' knowledge on irradiation, their self-perception of imaging prescriptions, and the use of CIGs. Materials and Methods A questionnaire of 21 items was self-administered between July and August 2016 to 155 referring physicians working in seven university-affiliated hospitals in Yaoundé and Douala (Cameroon). This pretested questionnaire based on imaging referral practices, the use and the need of CIGs, knowledge on radiation doses of 11 specific radiologic procedures, and knowledge of injurious effects of radiation was completed in the presence of the investigator. Scores were allocated for each question. Results 155 questionnaires were completed out of 180 administered (86.1%). Participants were 90 (58%) females, 63 (40.64%) specialists, 53 (34.20%) residents/interns, and 39 (25.16%) general practitioners. The average professional experience was 7.4 years (1–25 years). The mean knowledge score was 11.5/59 with no influence of sex, years of experience, and professional category. CIGs users' score was better than nonusers (means 14.2 versus 10.6; p < 0.01). 80% of physicians (124/155) underrated radiation doses of routine imaging exams. Seventy-eight (50.3%) participants have knowledge on CIGs and half of them made use of them. “Impact on diagnosis” was the highest justification criteria follow by “impact on treatment decision.” Unjustified requests were mainly for “patient expectation or will” or for “research motivations.” 96% of interviewees believed that making available national CIGs will improve justification. Conclusion Most physicians did not have appropriate awareness about radiation doses for routine imaging procedures. A small number of physicians have knowledge on CIGs but they believe that making available CIGs will improve justification of imaging procedures. Continuous trainings on radiation protection and implementation of national CIGs are therefore recommended. PMID:28630770

Facile Growth of Cu2ZnSnS4 Thin-Film by One-Step Pulsed Hybrid Electrophoretic and Electroplating Deposition

PubMed Central

Tsai, Hung-Wei; Chen, Chia-Wei; Thomas, Stuart R.; Hsu, Cheng-Hung; Tsai, Wen-Chi; Chen, Yu-Ze; Wang, Yi-Chung; Wang, Zhiming M.; Hong, Hwen-Fen; Chueh, Yu-Lun

2016-01-01

The use of costly and rare metals such as indium and gallium in Cu(In,Ga)Se2 (CIGS) based solar cells has motivated research into the use of Cu2ZnSnS4 (CZTS) as a suitable replacement due to its non-toxicity, abundance of compositional elements and excellent optical properties (1.5 eV direct band gap and absorption coefficient of ~104 cm−1). In this study, we demonstrate a one-step pulsed hybrid electrodeposition method (PHED), which combines electrophoretic and electroplating deposition to deposit uniform CZTS thin-films. Through careful analysis and optimization, we are able to demonstrate CZTS solar cells with the VOC, JSC, FF and η of 350 mV, 3.90 mA/cm2, 0.43 and 0.59%, respectively. PMID:26902556

Electronic Cigarettes: Their Constituents and Potential Links to Asthma.

PubMed

Clapp, Phillip W; Jaspers, Ilona

2017-10-05

Vaping is gaining popularity in the USA, particularly among teens and young adults. While e-cigs are commonly represented as safer alternatives to tobacco cigarettes, little is known regarding the health effects of their short- or long-term use, especially in individuals with pre-existing respiratory diseases such as asthma. Flavored e-cig liquids (e-liquids) and e-cig aerosols contain airway irritants and toxicants that have been implicated in the pathogenesis and worsening of lung diseases. In this review, we will summarize existing data on potential health effects of components present in e-cig aerosols, such as propylene glycol, vegetable glycerin, nicotine, and flavorings, and discuss their relevance in the context of asthma. Recent survey data indicate that adolescents with asthma had a higher prevalence of current e-cig use (12.4%) compared to their non-asthmatics peers (10.2%) and conveyed positive beliefs about tobacco products, especially e-cigs. Similarly, a study conducted among high school students from Ontario, Canada, indicated a greater likelihood of e-cig use in asthmatics as compared to their non-asthmatic peers. Availability of different flavorings is often cited as the main reason among youth/adolescents for trying e-cigs or switching from cigarettes to e-cigs. Occupational inhalation of some common food-safe flavoring agents is reported to cause occupational asthma and worsen asthmatic symptoms. Moreover, workplace inhalation exposures to the flavoring agent diacetyl have caused irreversible obstructive airway disease in healthy workers. Additionally, recent studies report that thermal decomposition of propylene glycol (PG) and vegetable glycerin (VG), the base constituents of e-liquids, produces reactive carbonyls, including acrolein, formaldehyde, and acetaldehyde, which have known respiratory toxicities. Furthermore, recent nicotine studies in rodents reveal that prenatal nicotine exposures lead to epigenetic reprogramming in the offspring, abnormal lung development, and multigenerational transmission of asthmatic-like symptoms. Comparisons of the toxicity and health effects of e-cigs and conventional cigarettes often focus on toxicants known to be present in cigarette smoke (CS) (i.e., formaldehyde, nitrosamines, etc.), as well as smoking-associated clinical endpoints, such as cancer, bronchitis, and chronic obstructive pulmonary disease (COPD). However, this approach disregards potential toxicity of components unique to flavored e-cigs, such as PG, VG, and the many different flavoring chemicals, which likely induce respiratory effects not usually observed in cigarette smokers.

Investigation of an Electrochemical Method for Separation of Copper, Indium, and Gallium from Pretreated CIGS Solar Cell Waste Materials

PubMed Central

Gustafsson, Anna M. K.; Björefors, Fredrik; Steenari, Britt-Marie

2015-01-01

Recycling of the semiconductor material copper indium gallium diselenide (CIGS) is important to ensure a future supply of indium and gallium, which are relatively rare and therefore expensive elements. As a continuation of our previous work, where we recycled high purity selenium from CIGS waste materials, we now show that copper and indium can be recycled by electrodeposition from hydrochloric acid solutions of dissolved selenium-depleted material. Suitable potentials for the reduction of copper and indium were determined to be −0.5 V and −0.9 V (versus the Ag/AgCl reference electrode), respectively, using cyclic voltammetry. Electrodeposition of first copper and then indium from a solution containing the dissolved residue from the selenium separation and ammonium chloride in 1 M HCl gave a copper yield of 100.1 ± 0.5% and an indium yield of 98.1 ± 2.5%. The separated copper and indium fractions contained no significant contamination of the other elements. Gallium remained in solution together with a small amount of indium after the separation of copper and indium and has to be recovered by an alternative method since electrowinning from the chloride-rich acid solution was not effective. PMID:26347901

CIG-P: Circular Interaction Graph for Proteomics.

PubMed

Hobbs, Christopher K; Leung, Michelle; Tsang, Herbert H; Ebhardt, H Alexander

2014-10-31

A typical affinity purification coupled to mass spectrometry (AP-MS) experiment includes the purification of a target protein (bait) using an antibody and subsequent mass spectrometry analysis of all proteins co-purifying with the bait (aka prey proteins). Like any other systems biology approach, AP-MS experiments generate a lot of data and visualization has been challenging, especially when integrating AP-MS experiments with orthogonal datasets. We present Circular Interaction Graph for Proteomics (CIG-P), which generates circular diagrams for visually appealing final representation of AP-MS data. Through a Java based GUI, the user inputs experimental and reference data as file in csv format. The resulting circular representation can be manipulated live within the GUI before exporting the diagram as vector graphic in pdf format. The strength of CIG-P is the ability to integrate orthogonal datasets with each other, e.g. affinity purification data of kinase PRPF4B in relation to the functional components of the spliceosome. Further, various AP-MS experiments can be compared to each other. CIG-P aids to present AP-MS data to a wider audience and we envision that the tool finds other applications too, e.g. kinase - substrate relationships as a function of perturbation. CIG-P is available under: http://sourceforge.net/projects/cig-p/

Comparative effects between electronic and cigarette smoke in human keratinocytes and epithelial lung cells.

PubMed

Cervellati, F; Muresan, X M; Sticozzi, C; Gambari, R; Montagner, G; Forman, H J; Torricelli, C; Maioli, E; Valacchi, G

2014-08-01

Information about the harmful effects of vaping is sparse and inconsistent, therefore, since the use of electronic cigarettes (e-CIGs) has become increasingly popular as a tool to limit tobacco smoking, it is urgent to establish the toxicity of the commercial e-CIGs. Skin (HaCaT) and lung (A549) cells, the main targets of cigarette smoke (CS), were exposed to e-CIG vapor and CS using an in vitro system. The cytotoxic effect of the exposure was analyzed in both cell types by ultrastructural morphology, Trypan Blue exclusion test and LDH assay. In addition, pro-inflammatory cytokines were measured by the Bio-Plex assay. The cytotoxic components of e-CIG were restrained to the flavoring compound and, to a lesser extent, to nicotine although their effects were less harmful to that of CS. Humectants alone exhibited no cytotoxicity but induced the release of cytokines and pro-inflammatory mediators. Based on our results, we can state that exposure to e-CIG vapors results in far less toxic than exposure to CS. In fact, besides the deleterious effect of flavor and nicotine, even the humectants alone are able to evocate cytokines release. This study will hopefully promote the development of safer e-CIGs to help people quit smoking. Copyright © 2014 Elsevier Ltd. All rights reserved.

A pattern-based analysis of clinical computer-interpretable guideline modeling languages.

PubMed

Mulyar, Nataliya; van der Aalst, Wil M P; Peleg, Mor

2007-01-01

Languages used to specify computer-interpretable guidelines (CIGs) differ in their approaches to addressing particular modeling challenges. The main goals of this article are: (1) to examine the expressive power of CIG modeling languages, and (2) to define the differences, from the control-flow perspective, between process languages in workflow management systems and modeling languages used to design clinical guidelines. The pattern-based analysis was applied to guideline modeling languages Asbru, EON, GLIF, and PROforma. We focused on control-flow and left other perspectives out of consideration. We evaluated the selected CIG modeling languages and identified their degree of support of 43 control-flow patterns. We used a set of explicitly defined evaluation criteria to determine whether each pattern is supported directly, indirectly, or not at all. PROforma offers direct support for 22 of 43 patterns, Asbru 20, GLIF 17, and EON 11. All four directly support basic control-flow patterns, cancellation patterns, and some advance branching and synchronization patterns. None support multiple instances patterns. They offer varying levels of support for synchronizing merge patterns and state-based patterns. Some support a few scenarios not covered by the 43 control-flow patterns. CIG modeling languages are remarkably close to traditional workflow languages from the control-flow perspective, but cover many fewer workflow patterns. CIG languages offer some flexibility that supports modeling of complex decisions and provide ways for modeling some decisions not covered by workflow management systems. Workflow management systems may be suitable for clinical guideline applications.

A formal approach to the analysis of clinical computer-interpretable guideline modeling languages.

PubMed

Grando, M Adela; Glasspool, David; Fox, John

2012-01-01

To develop proof strategies to formally study the expressiveness of workflow-based languages, and to investigate their applicability to clinical computer-interpretable guideline (CIG) modeling languages. We propose two strategies for studying the expressiveness of workflow-based languages based on a standard set of workflow patterns expressed as Petri nets (PNs) and notions of congruence and bisimilarity from process calculus. Proof that a PN-based pattern P can be expressed in a language L can be carried out semi-automatically. Proof that a language L cannot provide the behavior specified by a PNP requires proof by exhaustion based on analysis of cases and cannot be performed automatically. The proof strategies are generic but we exemplify their use with a particular CIG modeling language, PROforma. To illustrate the method we evaluate the expressiveness of PROforma against three standard workflow patterns and compare our results with a previous similar but informal comparison. We show that the two proof strategies are effective in evaluating a CIG modeling language against standard workflow patterns. We find that using the proposed formal techniques we obtain different results to a comparable previously published but less formal study. We discuss the utility of these analyses as the basis for principled extensions to CIG modeling languages. Additionally we explain how the same proof strategies can be reused to prove the satisfaction of patterns expressed in the declarative language CIGDec. The proof strategies we propose are useful tools for analysing the expressiveness of CIG modeling languages. This study provides good evidence of the benefits of applying formal methods of proof over semi-formal ones. Copyright © 2011 Elsevier B.V. All rights reserved.

Cu-In Halide Perovskite Solar Absorbers.

PubMed

Zhao, Xin-Gang; Yang, Dongwen; Sun, Yuanhui; Li, Tianshu; Zhang, Lijun; Yu, Liping; Zunger, Alex

2017-05-17

The long-term chemical instability and the presence of toxic Pb in otherwise stellar solar absorber APbX 3 made of organic molecules on the A site and halogens for X have hindered their large-scale commercialization. Previously explored ways to achieve Pb-free halide perovskites involved replacing Pb 2+ with other similar M 2+ cations in ns 2 electron configuration, e.g., Sn 2+ or by Bi 3+ (plus Ag + ), but unfortunately this showed either poor stability (M = Sn) or weakly absorbing oversized indirect gaps (M = Bi), prompting concerns that perhaps stability and good optoelectronic properties might be contraindicated. Herein, we exploit the electronic structure underpinning of classic Cu[In,Ga]Se 2 (CIGS) chalcopyrite solar absorbers to design Pb-free halide perovskites by transmuting 2Pb to the pair [B IB + C III ] such as [Cu + Ga] or [Ag + In] and combinations thereof. The resulting group of double perovskites with formula A 2 BCX 6 (A = K, Rb, Cs; B = Cu, Ag; C = Ga, In; X = Cl, Br, I) benefits from the ionic, yet narrow-gap character of halide perovskites, and at the same time borrows the advantage of the strong Cu(d)/Se(p) → Ga/In(s/p) valence-to-conduction-band absorption spectra known from CIGS. This constitutes a new group of CuIn-based Halide Perovskite (CIHP). Our first-principles calculations guided by such design principles indicate that the CIHPs class has members with clear thermodynamic stability, showing direct band gaps, and manifesting a wide-range of tunable gap values (from zero to about 2.5 eV) and combination of light electron and heavy-light hole effective masses. Materials screening of candidate CIHPs then identifies the best-of-class Rb 2 [CuIn]Cl 6 , Rb 2 [AgIn]Br 6 , and Cs 2 [AgIn]Br 6 , having direct band gaps of 1.36, 1.46, and 1.50 eV, and theoretical spectroscopic limited maximal efficiency comparable to chalcopyrites and CH 3 NH 3 PbI 3 . Our finding offers a new routine for designing new-type Pb-free halide perovskite solar absorbers.

Cd doping at PVD-CdS/CuInGaSe 2 heterojunctions

DOE PAGES

He, Xiaoqing; Paulauskas, Tadas; Ercius, Peter; ...

2017-02-20

In this paper, we report on direct evidence of Cd doping of the CuInGaSe 2 (CIGS) surface in physical vapor deposited (PVD) CdS/CIGS heterojunctions by scanning transmission electron microscopy (STEM) and related techniques. We find Cd doping of the CIGS near-surface region regardless of the presence or absence of Cu rich domains in the CdS for both zinc-blende (zb) and wurtzite (wz) CdS. However, we find that the Cd penetrates much farther into the CIGS when Cu-rich domains are present in the CdS. This suggests that Cu exchanges with Cd, increasing the concentration gradient for Cd in the CIGS andmore » thus driving Cd into the CIGS surface. The Cd doping is clearly resolved at atomic resolution in aberration-corrected STEM-high angle annular dark field images. In zb-CdS/CIGS heterojunctions, Cd is shown to substitute for both Cu and Ga atoms, while in wz-CdS/CIGS heterojunctions Cd seems to predominantly occupy Cu sites. Finally, Cd doping in the CIGS surface layer suggests the formation of a p-n homojunction in the CIGS, which may account for the high device efficiencies, comparable to CBD-CdS/CIGS processed structures.« less

Ecofriendly and Nonvacuum Electrostatic Spray-Assisted Vapor Deposition of Cu(In,Ga)(S,Se)2 Thin Film Solar Cells.

PubMed

Hossain, Md Anower; Wang, Mingqing; Choy, Kwang-Leong

2015-10-14

Chalcopyrite Cu(In,Ga)(S,Se)2 (CIGSSe) thin films have been deposited by a novel, nonvacuum, and cost-effective electrostatic spray-assisted vapor deposition (ESAVD) method. The generation of a fine aerosol of precursor solution, and their controlled deposition onto a molybdenum substrate, results in adherent, dense, and uniform Cu(In,Ga)S2 (CIGS) films. This is an essential tool to keep the interfacial area of thin film solar cells to a minimum value for efficient charge separation as it helps to achieve the desired surface smoothness uniformity for subsequent cadmium sulfide and window layer deposition. This nonvacuum aerosol based approach for making the CIGSSe film uses environmentally benign precursor solution, and it is cheaper for producing solar cells than that of the vacuum-based thin film solar technology. An optimized CIGSSe thin film solar cell with a device configuration of molybdenum-coated soda-lime glass substrate/CIGSSe/CdS/i-ZnO/AZO shows the photovoltaic (j-V) characteristics of Voc=0.518 V, jsc=28.79 mA cm(-2), fill factor=64.02%, and a promising power conversion efficiency of η=9.55% under simulated AM 1.5 100 mW cm(-2) illuminations, without the use of an antireflection layer. This demonstrates the potential of ESAVD deposition as a promising alternative approach for making thin film CIGSSe solar cells at a lower cost.

Real Time Spectroscopic Ellipsometry Analysis of First Stage CuIn1−xGaxSe2 Growth: Indium-Gallium Selenide Co-Evaporation

PubMed Central

Pradhan, Puja; Aryal, Puruswottam; Attygalle, Dinesh; Ibdah, Abdel-Rahman; Koirala, Prakash; Li, Jian; Bhandari, Khagendra P.; Liyanage, Geethika K.; Ellingson, Randy J.; Heben, Michael J.; Marsillac, Sylvain; Collins, Robert W.; Podraza, Nikolas J.

2018-01-01

Real time spectroscopic ellipsometry (RTSE) has been applied for in-situ monitoring of the first stage of copper indium-gallium diselenide (CIGS) thin film deposition by the three-stage co-evaporation process used for fabrication of high efficiency thin film photovoltaic (PV) devices. The first stage entails the growth of indium-gallium selenide (In1−xGax)2Se3 (IGS) on a substrate of Mo-coated soda lime glass maintained at a temperature of 400 °C. This is a critical stage of CIGS deposition because a large fraction of the final film thickness is deposited, and as a result precise compositional control is desired in order to achieve the optimum performance of the resulting CIGS solar cell. RTSE is sensitive to monolayer level film growth processes and can provide accurate measurements of bulk and surface roughness layer thicknesses. These in turn enable accurate measurements of the bulk layer optical response in the form of the complex dielectric function ε = ε1 − iε2, spectra. Here, RTSE has been used to obtain the (ε1, ε2) spectra at the measurement temperature of 400 °C for IGS thin films of different Ga contents (x) deduced from different ranges of accumulated bulk layer thickness during the deposition process. Applying an analytical expression in common for each of the (ε1, ε2) spectra of these IGS films, oscillator parameters have been obtained in the best fits and these parameters in turn have been fitted with polynomials in x. From the resulting database of polynomial coefficients, the (ε1, ε2) spectra can be generated for any composition of IGS from the single parameter, x. The results have served as an RTSE fingerprint for IGS composition and have provided further structural information beyond simply thicknesses, for example information related to film density and grain size. The deduced IGS structural evolution and the (ε1, ε2) spectra have been interpreted as well in relation to observations from scanning electron microscopy, X-ray diffractometry and energy-dispersive X-ray spectroscopy profiling analyses. Overall the structural, optical and compositional analysis possible by RTSE has assisted in understanding the growth and properties of three stage CIGS absorbers for solar cells and shows future promise for enhancing cell performance through monitoring and control. PMID:29337931

Real Time Spectroscopic Ellipsometry Analysis of First Stage CuIn1-xGaxSe₂ Growth: Indium-Gallium Selenide Co-Evaporation.

PubMed

Pradhan, Puja; Aryal, Puruswottam; Attygalle, Dinesh; Ibdah, Abdel-Rahman; Koirala, Prakash; Li, Jian; Bhandari, Khagendra P; Liyanage, Geethika K; Ellingson, Randy J; Heben, Michael J; Marsillac, Sylvain; Collins, Robert W; Podraza, Nikolas J

2018-01-16

Real time spectroscopic ellipsometry (RTSE) has been applied for in-situ monitoring of the first stage of copper indium-gallium diselenide (CIGS) thin film deposition by the three-stage co-evaporation process used for fabrication of high efficiency thin film photovoltaic (PV) devices. The first stage entails the growth of indium-gallium selenide (In 1- x Ga x )₂Se₃ (IGS) on a substrate of Mo-coated soda lime glass maintained at a temperature of 400 °C. This is a critical stage of CIGS deposition because a large fraction of the final film thickness is deposited, and as a result precise compositional control is desired in order to achieve the optimum performance of the resulting CIGS solar cell. RTSE is sensitive to monolayer level film growth processes and can provide accurate measurements of bulk and surface roughness layer thicknesses. These in turn enable accurate measurements of the bulk layer optical response in the form of the complex dielectric function ε = ε₁ - iε₂, spectra. Here, RTSE has been used to obtain the (ε₁, ε₂) spectra at the measurement temperature of 400 °C for IGS thin films of different Ga contents ( x ) deduced from different ranges of accumulated bulk layer thickness during the deposition process. Applying an analytical expression in common for each of the (ε₁, ε₂) spectra of these IGS films, oscillator parameters have been obtained in the best fits and these parameters in turn have been fitted with polynomials in x . From the resulting database of polynomial coefficients, the (ε₁, ε₂) spectra can be generated for any composition of IGS from the single parameter, x . The results have served as an RTSE fingerprint for IGS composition and have provided further structural information beyond simply thicknesses, for example information related to film density and grain size. The deduced IGS structural evolution and the (ε₁, ε₂) spectra have been interpreted as well in relation to observations from scanning electron microscopy, X-ray diffractometry and energy-dispersive X-ray spectroscopy profiling analyses. Overall the structural, optical and compositional analysis possible by RTSE has assisted in understanding the growth and properties of three stage CIGS absorbers for solar cells and shows future promise for enhancing cell performance through monitoring and control.

Health professionals in Flanders perceive the potential health risks of vaping as lower than those of smoking but do not recommend using e-cigarettes to their smoking patients.

PubMed

Van Gucht, Dinska; Baeyens, Frank

2016-06-24

Many misperceptions of both risks and opportunities of e-cigarettes (e-cigs) exist among the general population and among physicians, although e-cigs could be a valuable harm reduction tool for current smokers. Two groups in Flanders, namely general practitioners (GPs; family doctors) and tobacco counselors filled out an online questionnaire with regard to their attitudes and risk perceptions concerning e-cigs. Statements included were on the safety and the addictive properties of e-cigs in absolute terms, whereas other items compared e-cigs with regular tobacco cigarettes. Statements about possible "gateway" and "renormalization" effects, selling to minors, and use in public places and on the potential of e-cigs as a smoking cessation aid were also included. Respondents were also asked for the rate at which their patients asked information about e-cigs, if they would recommend e-cigs to their smoking patients, and whether they had information brochures on e-cigs. About 70 % believed that e-cigs are harmful to vapers, and about half to two thirds believed that e-cigs are carcinogenic, increase cardiovascular risk, and increase the risk of chronic lung disease. Also, a substantial minority incorrectly believed these risks to be no less than those resulting from regular smoking. Ten to almost 20 % disagreed that e-cigs are healthier and represent less risk for the main serious smoking-related diseases than conventional cigarettes. More than half of the respondents disagreed that e-cigs are an effective smoking cessation aid. None (0 %) offered the strongest level of agreement for recommending e-cigs to their clients/patients, but GPs agreed to a lesser degree a bit more often than tobacco counselors. Almost none had information leaflets for potentially interested patients. Finally, the majority of our sample also believed that e-cigs will cause renormalization of smoking and that e-cigs will lead to an uptake of conventional smoking and disagreed with allowing vaping in enclosed public places. Health professionals in Flanders perceive the potential health risks of vaping as lower than those of smoking but do not recommend using e-cigs to their smoking patients.

Development of CIGS2 Thin Films on Ultralightweight Flexible Large Area Foil Sunstrates

NASA Technical Reports Server (NTRS)

Dhere, Neelkanth G.; Gade, Vivek S.; Kadam, Ankur A.; Jahagirdar, Anant H.; Kulkarni, Sachin S.; Bet, Sachin M.

2005-01-01

The development of thin film solar cells is aimed at reducing the costs for photovoltaic systems. Use of thin film technology and thin foil substrate such as 5-mil thick stainless steel foil or 1-mil thick Ti would result in considerable costs savings. Another important aspect is manufacturing cost. Current single crystal technology for space power can cost more than $ 300 per watt at the array level and weigh more than 1 kg/sq m equivalent to specific power of approx. 65 W/kg. Thin film material such as CuIn1-xGaxS2 (CIGS2), CuIn(1-x)Ga(x)Se(2-y)S(y) (CIGSS) or amorphous hydrogenated silicon (a-Si:H) may be able to reduce both the cost and mass per unit area by an order of magnitude. Manufacturing costs for solar arrays are an important consideration for total spacecraft budget. For a medium sized 5kW satellite for example, the array manufacturing cost alone may exceed $ 2 million. Moving to thin film technology could reduce this expense to less than $ 500K. Earlier publications have demonstrated the potential of achieving higher efficiencies from CIGSS thin film solar cells on 5-mil thick stainless steel foil as well as initial stages of facility augmentation for depositing thin film solar cells on larger (6 in x 4 in) substrates. This paper presents the developmental study of achieving stress free Mo coating; uniform coatings of Mo back contact and metallic precursors. The paper also presents the development of sol gel process, refurbishment of selenization/sulfurization furnace, chemical bath deposition (CBD) for n-type CdS and scrubber for detoxification of H2S and H2Se gases.

Universality of Non-Ohmic Shunt Leakage in Thin-Film Solar Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dongaonkar, S.; Servaites, J.D.; Ford, G.M.

2010-01-01

We compare the dark current-voltage (IV) characteristics of three different thin-film solar cell types: hydrogenated amorphous silicon (a-Si:H) p-i-n cells, organic bulk heterojunction (BHJ) cells, and Cu(In,Ga)Se 2 (CIGS) cells. All three device types exhibit a significant shunt leakage current at low forward bias (V<~0.4) and reverse bias, which cannot be explained by the classical solar cell diode model. This parasitic shunt current exhibits non-Ohmic behavior, as opposed to the traditional constant shunt resistance model for photovoltaics. We show here that this shunt leakage (I sh) , across all three solar cell types considered, is characterized by the following commonmore » phenomenological features: (a) voltage symmetry about V=0 , (b) nonlinear (power law) voltage dependence, and (c) extremely weak temperature dependence. Based on this analysis, we provide a simple method of subtracting this shunt current component from the measured data and discuss its implications on dark IV parameter extraction. We propose a space charge limited (SCL) current model for capturing all these features of the shunt leakage in a consistent framework and discuss possible physical origin of the parasitic paths responsible for this shunt current mechanism.« less

Design and realization of transparent solar modules based on luminescent solar concentrators integrating nanostructured photonic crystals.

PubMed

Jiménez-Solano, Alberto; Delgado-Sánchez, José-Maria; Calvo, Mauricio E; Miranda-Muñoz, José M; Lozano, Gabriel; Sancho, Diego; Sánchez-Cortezón, Emilio; Míguez, Hernán

2015-12-01

Herein, we present a prototype of a photovoltaic module that combines a luminescent solar concentrator integrating one-dimensional photonic crystals and in-plane CuInGaSe 2 (CIGS) solar cells. Highly uniform and wide-area nanostructured multilayers with photonic crystal properties were deposited by a cost-efficient and scalable liquid processing amenable to large-scale fabrication. Their role is to both maximize light absorption in the targeted spectral range, determined by the fluorophore employed, and minimize losses caused by emission at angles within the escape cone of the planar concentrator. From a structural perspective, the porous nature of the layers facilitates the integration with the thermoplastic polymers typically used to encapsulate and seal these modules. Judicious design of the module geometry, as well as of the optical properties of the dielectric mirrors employed, allows optimizing light guiding and hence photovoltaic performance while preserving a great deal of transparency. Optimized in-plane designs like the one herein proposed are of relevance for building integrated photovoltaics, as ease of fabrication, long-term stability and improved performance are simultaneously achieved. © 2015 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd.

Design and realization of transparent solar modules based on luminescent solar concentrators integrating nanostructured photonic crystals

PubMed Central

Jiménez‐Solano, Alberto; Delgado‐Sánchez, José‐Maria; Calvo, Mauricio E.; Miranda‐Muñoz, José M.; Lozano, Gabriel; Sancho, Diego; Sánchez‐Cortezón, Emilio

2015-01-01

Abstract Herein, we present a prototype of a photovoltaic module that combines a luminescent solar concentrator integrating one‐dimensional photonic crystals and in‐plane CuInGaSe2 (CIGS) solar cells. Highly uniform and wide‐area nanostructured multilayers with photonic crystal properties were deposited by a cost‐efficient and scalable liquid processing amenable to large‐scale fabrication. Their role is to both maximize light absorption in the targeted spectral range, determined by the fluorophore employed, and minimize losses caused by emission at angles within the escape cone of the planar concentrator. From a structural perspective, the porous nature of the layers facilitates the integration with the thermoplastic polymers typically used to encapsulate and seal these modules. Judicious design of the module geometry, as well as of the optical properties of the dielectric mirrors employed, allows optimizing light guiding and hence photovoltaic performance while preserving a great deal of transparency. Optimized in‐plane designs like the one herein proposed are of relevance for building integrated photovoltaics, as ease of fabrication, long‐term stability and improved performance are simultaneously achieved. © 2015 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd. PMID:27656090

Interfaces of high-efficiency kesterite Cu2ZnSnS(e)4 thin film solar cells

NASA Astrophysics Data System (ADS)

Gao, Shoushuai; Jiang, Zhenwu; Wu, Li; Ao, Jianping; Zeng, Yu; Sun, Yun; Zhang, Yi

2018-01-01

Cu2ZnSnS(e)4 (CZTS(e)) solar cells have attracted much attention due to the elemental abundance and the non-toxicity. However, the record efficiency of 12.6% for Cu2ZnSn(S,Se)4 (CZTSSe) solar cells is much lower than that of Cu(In,Ga)Se2 (CIGS) solar cells. One crucial reason is the recombination at interfaces. In recent years, large amount investigations have been done to analyze the interfacial problems and improve the interfacial properties via a variety of methods. This paper gives a review of progresses on interfaces of CZTS(e) solar cells, including: (1) the band alignment optimization at buffer/CZTS(e) interface, (2) tailoring the thickness of MoS(e)2 interfacial layers between CZTS(e) absorber and Mo back contact, (3) the passivation of rear interface, (4) the passivation of front interface, and (5) the etching of secondary phases.

Hyaluronan and Layilin Mediate Loss of Airway Epithelial Barrier Function Induced by Cigarette Smoke by Decreasing E-cadherin*

PubMed Central

Forteza, Rosanna Malbran; Casalino-Matsuda, S. Marina; Falcon, Nieves S.; Valencia Gattas, Monica; Monzon, Maria E.

2012-01-01

Cigarette smoke (CigS) exposure is associated with increased bronchial epithelial permeability and impaired barrier function. Primary cultures of normal human bronchial epithelial cells exposed to CigS exhibit decreased E-cadherin expression and reduced transepithelial electrical resistance. These effects were mediated by hyaluronan (HA) because inhibition of its synthesis with 4-methylumbelliferone prevented these effects, and exposure to HA fragments of <70 kDa mimicked these effects. We show that the HA receptor layilin is expressed apically in human airway epithelium and that cells infected with lentivirus expressing layilin siRNAs were protected against increased permeability triggered by both CigS and HA. We identified RhoA/Rho-associated protein kinase (ROCK) as the signaling effectors downstream layilin. We conclude that HA fragments generated by CigS bind to layilin and signal through Rho/ROCK to inhibit the E-cadherin gene and protein expression, leading to a loss of epithelial cell-cell contact. These studies suggest that HA functions as a master switch protecting or disrupting the epithelial barrier in its high versus low molecular weight form and that its depolymerization is a first and necessary step triggering the inflammatory response to CigS. PMID:23048036

Effectiveness of a Littoral Combat Ship as a Major Node in a Wireless Mesh Network

DTIC Science & Technology

2017-03-01

17 Figure 6. Cloud Relay Groups . Source: Persistent Systems (2014a). .......................18 Figure 7. SolarWinds Network Performance Monitor...CIG Commander’s Initiative Group CLI Command Line Interface CN Core Network CODA Common Optical Digital Architecture CPS Cyber-Physical Systems...CSBA Center for Strategic and Budgetary CSG Carrier Strike Group DAMA Demand Assigned Multiple Access DDG Guided Missile Destroyer DL Distributed

Influence of Annealing Temperature on Some Optical and Structural Properties of Cu2ZnSnS4 Deposited by CZT Co-Electrodeposition Coupled with Chemical Bath Technique

NASA Astrophysics Data System (ADS)

Okoth, Obila Jorim; Domtau, Dinfa Luka; Marina, Mukabi; John, Onyatta; Awuor, Ogacho Alex

Copper indium gallium selenide (CIGS) is currently most efficient thin film solar technology in use but it is faced with problems of material scarcity and toxicity. An alternative earth abundant and non-toxic materials consisting of Cu2ZnSnS4 (CZTS) have been investigated as a replacement for CIGS. In this work, CZTS thin films deposited by low cost co-electrodeposition, at a potential of -1.2V, coupled with chemical bath techniques at room temperature and then annealed under sulphur rich atmosphere were investigated. CZTS thin film quality determination was carried out using Raman spectroscopy which confirmed formation of quality CZTS film, main Raman peaks at 288cm-1 and 338cm-1 were observed. Electrical characterization was carried out using four-point probe instrument and the resistivity was in the order of ˜10-4Ω-cm. The optical characterization was done using UV-VIS-NIR spectrophotometer. The bandgaps of the annealed CZTS film ranged from 1.45 to 1.94eV with absorption coefficient of order ˜104cm-1 in the visible and near infrared range of the solar spectrum were observed.

Characterization of efficiency-limiting resistance losses in monolithically integrated Cu(In,Ga)Se2 solar modules

PubMed Central

Yoon, Ju-Heon; Park, Jong-Keuk; Kim, Won Mok; Lee, JinWoo; Pak, Hisun; Jeong, Jeung-hyun

2015-01-01

The cell-to-module efficiency gap in Cu(In,Ga)Se2 (CIGS) monolithically integrated solar modules is enhanced by contact resistance between the Al-doped ZnO (AZO) and Mo back contact layers, the P2 contact, which connects adjacent cells. The present work evaluated the P2 contact resistance, in addition to the TCO resistance, using an embedded transmission line structure in a commercial-grade module without using special sample fabrication methods. The AZO layers between cells were not scribed; instead, the CIGS/CdS/i-ZnO/AZO device was patterned in a long stripe to permit measurement of the Mo electrode pair resistance over current paths through two P2 contacts (Mo/AZO) and along the AZO layer. The intercept and slope of the resistance as a function of the electrode interval yielded the P2 contact resistance and the TCO resistance, respectively. Calibration of the parasitic resistances is discussed as a method of improving the measurement accuracy. The contribution of the P2 contact resistance to the series resistance was comparable to that of the TCO resistance, and its origin was attributed to remnant MoSe2 phases in the P2 region, as verified by transmission electron microscopy. PMID:25573530

Interplay between Clinical Guidelines and Organizational Workflow Systems. Experience from the MobiGuide Project.

PubMed

Shabo, Amnon; Peleg, Mor; Parimbelli, Enea; Quaglini, Silvana; Napolitano, Carlo

2016-12-07

Implementing a decision-support system within a healthcare organization requires integration of clinical domain knowledge with resource constraints. Computer-interpretable guidelines (CIG) are excellent instruments for addressing clinical aspects while business process management (BPM) languages and Workflow (Wf) engines manage the logistic organizational constraints. Our objective is the orchestration of all the relevant factors needed for a successful execution of patient's care pathways, especially when spanning the continuum of care, from acute to community or home care. We considered three strategies for integrating CIGs with organizational workflows: extending the CIG or BPM languages and their engines, or creating an interplay between them. We used the interplay approach to implement a set of use cases arising from a CIG implementation in the domain of Atrial Fibrillation. To provide a more scalable and standards-based solution, we explored the use of Cross-Enterprise Document Workflow Integration Profile. We describe our proof-of-concept implementation of five use cases. We utilized the Personal Health Record of the MobiGuide project to implement a loosely-coupled approach between the Activiti BPM engine and the Picard CIG engine. Changes in the PHR were detected by polling. IHE profiles were used to develop workflow documents that orchestrate cross-enterprise execution of cardioversion. Interplay between CIG and BPM engines can support orchestration of care flows within organizational settings.

Impedance-Based Stability Analysis in Grid Interconnection Impact Study Owing to the Increased Adoption of Converter-Interfaced Generators

DOE PAGES

Cho, Youngho; Hur, Kyeon; Kang, Yong; ...

2017-09-08

This study investigates the emerging harmonic stability concerns to be addressed by grid planners in generation interconnection studies, owing to the increased adoption of renewable energy resources connected to the grid via power electronic converters. The wideband and high-frequency electromagnetic transient (EMT) characteristics of these converter-interfaced generators (CIGs) and their interaction with the grid impedance are not accurately captured in the typical dynamic studies conducted by grid planners. This paper thus identifies the desired components to be studied and subsequently develops a practical process for integrating a new CIG into a grid with the existing CIGs. The steps of thismore » process are as follows: the impedance equation of a CIG using its control dynamics and an interface filter to the grid, for example, an LCL filter (inductor-capacitor-inductor type), is developed; an equivalent impedance model including the existing CIGs nearby and the grid observed from the point of common coupling are derived; the system stability for credible operating scenarios is assessed. Detailed EMT simulations validate the accuracy of the impedance models and stability assessment for various connection scenarios. Here, by complementing the conventional EMT simulation studies, the proposed analytical approach enables grid planners to identify critical design parameters for seamlessly integrating a new CIG and ensuring the reliability of the grid.« less

Cu(In,Ga)S2, Thin-Film Solar Cells Prepared by H2S Sulfurization of CuGa-In Precursor

NASA Technical Reports Server (NTRS)

Dhere, Neelkanth G.; Kulkarni, Shashank R.; Chavan, Sanjay S.; Ghongadi, Shantinath R.

2005-01-01

Thin-film CuInS2 solar cell is the leading candidate for space power because of bandgap near the optimum value for AM0 solar radiation outside the earth's atmosphere, excellent radiation hardness, and freedom from intrinsic degradation mechanisms unlike a-Si:H cells. Ultra-lightweight thin-film solar cells deposited on flexible polyimide plastic substrates such as Kapton(trademark), Upilex(trademark), and Apical(trademark) have a potential for achieving specific power of 1000 W/kg, while the state-of-art specific power of the present day solar cells is 66 W/kg. This paper describes the preparation of Cu-rich CuIn(sub 1-x)Ga(sub x)S(sub 2) (CIGS2) thin films and solar cells by a process of sulfurization of CuGa-In precursor similar to that being used for preparation of large-compact-grain CuIn(sub 1-x)Ga(sub x)Se2 thin films and efficient solar cells at FSEC PV Materials Lab.

Exploratory Analysis of Marketing and Non-marketing E-cigarette Themes on Twitter

PubMed Central

Han, Sifei

2017-01-01

Electronic cigarettes (e-cigs) have been gaining popularity and have emerged as a controversial tobacco product since their introduction in 2007 in the U.S. The smoke-free aspect of e-cigs renders them less harmful than conventional cigarettes and is one of the main reasons for their use by people who plan to quit smoking. The US food and drug administration (FDA) has introduced new regulations early May 2016 that went into effect on August 8, 2016. Given this important context, in this paper, we report results of a project to identify current themes in e-cig tweets in terms of semantic interpretations of topics generated with topic modeling. Given marketing/advertising tweets constitute almost half of all e-cig tweets, we first build a classifier that identifies marketing and non-marketing tweets based on a hand-built dataset of 1000 tweets. After applying the classifier to a dataset of over a million tweets (collected during 4/2015 – 6/2016), we conduct a preliminary content analysis and run topic models on the two sets of tweets separately after identifying the appropriate numbers of topics using topic coherence. We interpret the results of the topic modeling process by relating topics generated to specific e-cig themes. We also report on themes identified from e-cig tweets generated at particular places (such as schools and churches) for geo-tagged tweets found in our dataset using the GeoNames API. To our knowledge, this is the first effort that employs topic modeling to identify e-cig themes in general and in the context of geo-tagged tweets tied to specific places of interest. PMID:28782062

Exploratory Analysis of Marketing and Non-marketing E-cigarette Themes on Twitter.

PubMed

Han, Sifei; Kavuluru, Ramakanth

2016-11-01

Electronic cigarettes (e-cigs) have been gaining popularity and have emerged as a controversial tobacco product since their introduction in 2007 in the U.S. The smoke-free aspect of e-cigs renders them less harmful than conventional cigarettes and is one of the main reasons for their use by people who plan to quit smoking. The US food and drug administration (FDA) has introduced new regulations early May 2016 that went into effect on August 8, 2016. Given this important context, in this paper, we report results of a project to identify current themes in e-cig tweets in terms of semantic interpretations of topics generated with topic modeling. Given marketing/advertising tweets constitute almost half of all e-cig tweets, we first build a classifier that identifies marketing and non-marketing tweets based on a hand-built dataset of 1000 tweets. After applying the classifier to a dataset of over a million tweets (collected during 4/2015 - 6/2016), we conduct a preliminary content analysis and run topic models on the two sets of tweets separately after identifying the appropriate numbers of topics using topic coherence. We interpret the results of the topic modeling process by relating topics generated to specific e-cig themes. We also report on themes identified from e-cig tweets generated at particular places (such as schools and churches) for geo-tagged tweets found in our dataset using the GeoNames API. To our knowledge, this is the first effort that employs topic modeling to identify e-cig themes in general and in the context of geo-tagged tweets tied to specific places of interest.

Enjoyment and other reasons for electronic cigarette use: Results from college students in New York.

PubMed

Saddleson, M L; Kozlowski, L T; Giovino, G A; Goniewicz, M L; Mahoney, M C; Homish, G G; Arora, A

2016-03-01

Young people are more likely to have experimented with e-cigarettes (e-cigs) compared with older adults. Few studies identify reasons for experimentation/use of e-cigs among young people; we sought to discover what drives college students to use e-cigs. Undergraduate students (ages 18-23) at four universities in New York State were surveyed. Among e-cig ever users (n=429), reasons for use were examined. A multinomial logistic regression model analyzed the relative risk of reasons for using e-cigs among discontinued, current non-daily and current daily e-cig users. Using e-cigs for enjoyment was associated with current non-daily (RR=2.11, 95% CI=1.18-3.75) and current daily use (RR=19.1, 95% CI=3.71-98.54). Non-daily use was related to use because e-cigs are less toxic than cigarettes (RR=2.80, 95% CI=1.75-4.50). More daily users reported use to quit smoking compared with either non-daily or discontinued users (53.3% vs. 12.2% and 13.3%, respectively; p<0.05). Among current users, 72.3% used for enjoyment, compared with 42.9% of discontinued users (p<0.05). In contrast to adults, who often report e-cig use to quit smoking, young people are less likely to use for this reason. The exception was daily e-cig users, who often reported use for quitting/reduction of smoking. Rather, college students report usage reasons related to affect (e.g. enjoyment). Overall, enjoyment was reported more often than was use for quitting smoking; affective reasons likely play a role in the popularity of e-cigs and should be considered in future assessments of e-cig users. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of ICP-OES to the determination of CuIn(1-x)Ga(x)Se2 thin films used as absorber materials in solar cell devices.

PubMed

Fernández-Martínez, Rodolfo; Caballero, Raquel; Guillén, Cecilia; Gutiérrez, María Teresa; Rucandio, María Isabel

2005-05-01

CuIn(1-x)Ga(x)Se2 [CIGS; x=Ga/(In+Ga)] thin films are among of the best candidates as absorber materials for solar cell applications. The material quality and main properties of the polycrystalline absorber layer are critically influenced by deviations in the stoichiometry, particularly in the Cu/(In+Ga) atomic ratio. In this work a simple, sensitive and accurate method has been developed for the quantitative determination of these thin films by inductively coupled plasma optical emission spectrometry (ICP-OES). The proposed method involves an acid digestion of the samples to achieve the complete solubilization of CIGS, followed by the analytical determination by ICP-OES. A digestion procedure with 50% HNO3 alone or in the presence of 10% HCl was performed to dissolve those thin films deposited on glass or Mo-coated glass substrates, respectively. Two analytical lines were selected for each element (Cu 324.754 and 327.396 nm, Ga 294.364 and 417.206 nm, In 303.936 and 325.609 nm, Se 196.090 and 203.985 nm, and Mo 202.030 and 379.825 nm) and a study of spectral interferences was performed which showed them to be suitable, since they offered a high sensitivity and no significant inter-element interferences were detected. Detection limits for all elements at the selected lines were found to be appropriate for this kind of application, and the relative standard deviations were lower than 1.5% for all elements with the exception of Se (about 5%). The Cu/(In+Ga) atomic ratios obtained from the application of this method to CIGS thin films were consistent with the study of the structural and morphological properties by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Toward automated e-cigarette surveillance: Spotting e-cigarette proponents on Twitter.

PubMed

Kavuluru, Ramakanth; Sabbir, A K M

2016-06-01

Electronic cigarettes (e-cigarettes or e-cigs) are a popular emerging tobacco product. Because e-cigs do not generate toxic tobacco combustion products that result from smoking regular cigarettes, they are sometimes perceived and promoted as a less harmful alternative to smoking and also as means to quit smoking. However, the safety of e-cigs and their efficacy in supporting smoking cessation is yet to be determined. Importantly, the federal drug administration (FDA) currently does not regulate e-cigs and as such their manufacturing, marketing, and sale is not subject to the rules that apply to traditional cigarettes. A number of manufacturers, advocates, and e-cig users are actively promoting e-cigs on Twitter. We develop a high accuracy supervised predictive model to automatically identify e-cig "proponents" on Twitter and analyze the quantitative variation of their tweeting behavior along popular themes when compared with other Twitter users (or tweeters). Using a dataset of 1000 independently annotated Twitter profiles by two different annotators, we employed a variety of textual features from latest tweet content and tweeter profile biography to build predictive models to automatically identify proponent tweeters. We used a set of manually curated key phrases to analyze e-cig proponent tweets from a corpus of over one million e-cig tweets along well known e-cig themes and compared the results with those generated by regular tweeters. Our model identifies e-cig proponents with 97% precision, 86% recall, 91% F-score, and 96% overall accuracy, with tight 95% confidence intervals. We find that as opposed to regular tweeters that form over 90% of the dataset, e-cig proponents are a much smaller subset but tweet two to five times more than regular tweeters. Proponents also disproportionately (one to two orders of magnitude more) highlight e-cig flavors, their smoke-free and potential harm reduction aspects, and their claimed use in smoking cessation. Given FDA is currently in the process of proposing meaningful regulation, we believe our work demonstrates the strong potential of informatics approaches, specifically machine learning, for automated e-cig surveillance on Twitter. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of the environment on galaxies in the Catalogue of Isolated Galaxies: physical satellites and large scale structure

NASA Astrophysics Data System (ADS)

Argudo-Fernández, M.; Verley, S.; Bergond, G.; Sulentic, J.; Sabater, J.; Fernández Lorenzo, M.; Espada, D.; Leon, S.; Sánchez-Expósito, S.; Santander-Vela, J. D.; Verdes-Montenegro, L.

2014-04-01

Context. We present a study of the 3D environment for a sample of 386 galaxies in the Catalogue of Isolated Galaxies (CIG, Karachentseva 1973) using the Ninth Data Release of the Sloan Digital Sky Survey (SDSS-DR9). Aims: We aim to identify and quantify the effects of the satellite distribution around a sample of galaxies in the CIG, as well as the effects of the large-scale structure (LSS). Methods: To recover the physically bound galaxies we first focused on the satellites that are within the escape speed of each CIG galaxy. We also propose a more conservative method using the stacked Gaussian distribution of the velocity difference of the neighbours. The tidal strengths affecting the primary galaxy were estimated to quantify the effects of the local and LSS environments. We also defined the projected number density parameter at the fifth nearest neighbour to characterise the LSS around the CIG galaxies. Results: Out of the 386 CIG galaxies considered in this study, at least 340 (88% of the sample) have no physically linked satellite. Following the more conservative Gaussian distribution of physical satellites around the CIG galaxies leads to upper limits. Out of the 386 CIG galaxies, 327 (85% of the sample) have no physical companion within a projected distance of 0.3 Mpc. The CIG galaxies are distributed following the LSS of the local Universe, although presenting a large heterogeneity in their degree of connection with it. When present around a CIG galaxy, the effect of physically bound galaxies largely dominates (typically by more than 90%) the tidal strengths generated by the LSS. Conclusions: The CIG samples a variety of environments, from galaxies with physical satellites to galaxies without neighbours within 3 Mpc. A clear segregation appears between early-type CIG galaxies with companions and isolated late-type CIG galaxies. Isolated galaxies are in general bluer, with probably younger stellar populations and very high star formation compared with older, redder CIG galaxies with companions. Reciprocally, the satellites are redder and with an older stellar populations around massive early-type CIG galaxies, while they have a younger stellar content around massive late-type CIG galaxies. This suggests that the CIG is composed of a heterogeneous population of galaxies, sampling from old to more recent, dynamical systems of galaxies. CIG galaxies with companions might have a mild tendency (0.3-0.4 dex) to be more massive, and may indicate a higher frequency of having suffered a merger in the past. The full Table 1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/564/A94

Ternary Precursors for Depositing I-III-VI2 Thin Films for Solar Cells via Spray CVD

NASA Technical Reports Server (NTRS)

Banger, K. K.; Hollingsworth, J. A.; Jin, M. H.-C.; Harris, J. D.; Duraj, S. A.; Smith, M.; Scheiman, D.; Bohannan, E. W.; Switzer, J. A.; Buhro, W. E.

2002-01-01

The development of thin-film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution to fabricating solar arrays with high specific power (W/kg). Thin-film fabrication studies demonstrate that ternary single source precursors (SSP's) can be used in either a hot or cold-wall spray chemical vapour deposition (CVD) reactor, for depositing CuInS2, CuGaS2, and CuGaInS2 at reduced temperatures (400 to 450 C), which display good electrical and optical properties suitable for photovoltaic (PV) devices. X-ray diffraction studies, energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM) confirmed the formation of the single phase CIS, CGS, CIGS thin-films on various substrates at reduced temperatures.

Toward maximum transmittance into absorption layers in solar cells: investigation of lossy-film-induced mismatches between reflectance and transmittance extrema.

PubMed

Chang, Yin-Jung; Lai, Chi-Sheng

2013-09-01

The mismatch in film thickness and incident angle between reflectance and transmittance extrema due to the presence of lossy film(s) is investigated toward the maximum transmittance design in the active region of solar cells. Using a planar air/lossy film/silicon double-interface geometry illustrates important and quite opposite mismatch behaviors associated with TE and TM waves. In a typical thin-film CIGS solar cell, mismatches contributed by TM waves in general dominate. The angular mismatch is at least 10° in about 37%-53% of the spectrum, depending on the thickness combination of all lossy interlayers. The largest thickness mismatch of a specific interlayer generally increases with the thickness of the layer itself. Antireflection coating designs for solar cells should therefore be optimized in terms of the maximum transmittance into the active region, even if the corresponding reflectance is not at its minimum.

Advanced Computer Image Generation Techniques Exploiting Perceptual Characteristics. Final Report.

ERIC Educational Resources Information Center

Stenger, Anthony J.; And Others

This study suggests and identifies computer image generation (CIG) algorithms for visual simulation that improve the training effectiveness of CIG simulators and identifies areas of basic research in visual perception that are significant for improving CIG technology. The first phase of the project entailed observing three existing CIG simulators.…

[Effects of cornel iridoid glycoside on activity of cholinesterases in vitro].

PubMed

Chu, Si-Juan; Zhang, Lan; Liu, Gang; Zhou, Wen-Xia; Li, Lin

2013-05-01

The purpose of the present study was to investigate the effects of cornel iridoid glycoside (CIG) on the activity of cholinesterases in vitro, and to investigate the mechanism of CIG's treating Alzheimer's disease (AD). The sources of cholinesterases were prepared from human blood cells, rat brain homogenate and human blood plasma, respectively. The biochemical methods were used to detect the activity of acetylcholine esterase (AChE) and butyryl cholinesterase (BuChE) to investigate the influence of CIG on cholinesterases. The results showed that CIG inhibited the activity of AChE of human blood cells and rat brain homogenate, with the 50% inhibition rate (IC50) of 1.6 g . L-1 and 3.3 g . L-1, respectively; and the inhibition of AChE of CIG is reversible. CIG also inhibited the activity of BuChE of human blood plasma, with the IC50 of 2.9 g . L-1. In conclusion, CIG can inhibit the activity of AChE and BuChE in vitro, which may be one of the mechanisms of CIG to treat AD.

Limited mutagenicity of electronic cigarettes in mouse or human cells in vitro.

PubMed

Tommasi, Stella; Bates, Steven E; Behar, Rachel Z; Talbot, Prue; Besaratinia, Ahmad

2017-10-01

Electronic cigarettes (e-cig), which are promoted as safe alternatives to tobacco cigarettes or as aides to smoking cessation, are becoming increasingly popular among adult chronic smokers and adolescents experimenting with tobacco products. Despite the known presence of toxicants and carcinogens in e-cig liquid and vapor, the possible carcinogenic effects of e-cig use in humans are unknown. We have utilized two validated in vitro model systems to investigate whether e-cig vapor induces mutation in mouse or human cells. We have exposed transgenic mouse fibroblasts in vitro to e-cig vapor extracts prepared from three popular brands, and determined the induction of mutagenesis in a reporter gene, the cII transgene. Furthermore, we have treated the pSP189 plasmid with e-cig vapor extract, transfected human fibroblast cells with the e-cig-treated plasmid, and screened for the induced mutations in the supF gene. We observed no statistically significant increases in relative mutant frequency in the cII transgene or supF gene in the e-cig treated mouse or human cells, respectively. Our data indicate that e-cig vapor extracts from the selected brands and at concentrations tested in this study have limited mutagenicity in both mouse and human cells in vitro. Copyright © 2017 Elsevier B.V. All rights reserved.

Combinatorial sputtering of Ga-doped (Zn,Mg)O for contact applications in solar cells

DOE PAGES

Rajbhandari, Pravakar P.; Bikowski, Andre; Perkins, John D.; ...

2016-09-20

In this study, the development of tunable contact materials based on environmentally friendly chemical elements using scalable deposition approaches is necessary for existing and emerging solar energy conversion technologies. In this paper, the properties of ZnO alloyed with magnesium (Mg), and doped with gallium (Ga) are studied using combinatorial thin film experiments. As a result of these studies, the optical band gap of the sputtered Zn 1-xMg xO thin films was determined to vary from 3.3 to 3.6 eV for a compositional spread of Mg content in the 0.04 < x < 0.17 range. Depending on whether or not Gamore » dopants were added, the electron concentrations were on the order of 10 17 cm -3 or 10 20 cm -3, respectively. Based on these results and on the Kelvin Probe work function measurements, a band diagram was derived using basic semiconductor physics equations. The quantitative determination of how the energy levels of Ga-doped (Zn, Mg)O thin films change as a function of Mg composition presented here, will facilitate their use as optimized contact layers for both Cu 2ZnSnS 4 (CZTS), Cu(In, Ga)Se 2 (CIGS) and other solar cell absorbers.« less

Effects of nicotine versus placebo e-cigarette use on symptom relief during initial tobacco abstinence.

PubMed

Perkins, Kenneth A; Karelitz, Joshua L; Michael, Valerie C

2017-08-01

Because electronic cigarettes (e-cigs) containing nicotine may relieve smoking abstinence symptoms similar to nicotine replacement therapy medication, we used within-subjects designs to test these effects with a first-generation e-cig in nonquitting and quitting smokers. In Study 1, 28 nontreatment-seeking smokers abstained overnight prior to each of 3 sessions. Minnesota Nicotine Withdrawal Scale (MNWS) withdrawal (and craving item) relief was assessed following 4 exposures (each 10 puffs) over 2 hr to e-cigs that either did (36 mg/ml) or did not (i.e., placebo, 0 mg/ml) contain nicotine or after no e-cig. Relief was greater after nicotine versus placebo e-cig (p < .05) but not after placebo versus no e-cig, showing relief was due to nicotine per se and not simple e-cig use behavior. Using a crossover design in Study 2, smokers preparing to quit soon engaged in 2 experimental 4-day quit periods on separate weeks. In weeks 1 and 3, all received a nicotine or placebo e-cig on Monday to use ad libitum while trying to abstain from smoking on Tuesday through Friday. (Week 2 involved resumption of ad libitum smoking.) MNWS and Questionnaire of Smoking Urges (QSU) craving were assessed at daily visits following 24-hr abstinence. Of 17 enrolled, 12 quit for ≥24 hr at least once, allowing test of relief because of e-cig use on quit days. Withdrawal and craving were reduced because of nicotine versus placebo e-cig use (both p < .05). In sum, compared with placebo e-cigs, nicotine e-cigs can relieve smoking abstinence symptoms, perhaps in a manner similar to Food and Drug Administration-approved nicotine replacement therapy products, although much more research with larger samples is needed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

META-GLARE: A meta-system for defining your own computer interpretable guideline system-Architecture and acquisition.

PubMed

Bottrighi, Alessio; Terenziani, Paolo

2016-09-01

Several different computer-assisted management systems of computer interpretable guidelines (CIGs) have been developed by the Artificial Intelligence in Medicine community. Each CIG system is characterized by a specific formalism to represent CIGs, and usually provides a manager to acquire, consult and execute them. Though there are several commonalities between most formalisms in the literature, each formalism has its own peculiarities. The goal of our work is to provide a flexible support to the extension or definition of CIGs formalisms, and of their acquisition and execution engines. Instead of defining "yet another CIG formalism and its manager", we propose META-GLARE (META Guideline Acquisition, Representation, and Execution), a "meta"-system to define new CIG systems. In this paper, META-GLARE, a meta-system to define new CIG systems, is presented. We try to capture the commonalities among current CIG approaches, by providing (i) a general manager for the acquisition, consultation and execution of hierarchical graphs (representing the control flow of actions in CIGs), parameterized over the types of nodes and of arcs constituting it, and (ii) a library of different elementary components of guidelines nodes (actions) and arcs, in which each type definition involves the specification of how objects of this type can be acquired, consulted and executed. We provide generality and flexibility, by allowing free aggregations of such elementary components to define new primitive node and arc types. We have drawn several experiments, in which we have used META-GLARE to build a CIG system (Experiment 1 in Section 8), or to extend it (Experiments 2 and 3). Such experiments show that META-GLARE provides a useful and easy-to-use support to such tasks. For instance, re-building the Guideline Acquisition, Representation, and Execution (GLARE) system using META-GLARE required less than one day (Experiment 1). META-GLARE is a meta-system for CIGs supporting fast prototyping. Since META-GLARE provides acquisition and execution engines that are parametric over the specific CIG formalism, it supports easy update and construction of CIG systems. Copyright © 2016 Elsevier B.V. All rights reserved.

Electrical properties of aluminum contacts deposited by DC sputtering method for photovoltaic applications

NASA Astrophysics Data System (ADS)

Krawczak, Ewelina; Gułkowski, Sławomir

2017-10-01

The use of aluminum contacts is common in the process of silicon solar cells production because of low contact resistivity. It has also a great importance in thin film technology for photovoltaics, especially in copper-indium-gallium-diselenide (CIGS) devices. The final stage of CIGS cell production is the top contact deposition of high conductivity layer for lateral current collection. Such material has to be highly optically transparent as well. In order to make a contact, metal is deposited onto TCO layer with minimum shadowing to allow as much light as possible into device. The metal grid contact is being made by deposition of few microns of aluminum. The resistivity of the deposited material as well as resistance between the metal grid and TCO layer plays a great role in high quality solar cell production. This paper presents the results of four point probe conductivity analysis of Al thin films deposited by direct current (DC) magnetron sputtering method. Influence of technological parameters of the Al deposition process on sheet resistance of deposited layers has been showed. In order to obtain the lowest resistivity of the thin contact layer, optimal set of sputtering parameters, i.e. power applied, deposition time and deposition pressure was found. The resistivity of the contact between two adjacent Al metal fingers deposited onto transparent conductive Al-doped zinc oxide film has been also examined.

Surface Passivation for Reliable Measurement of Bulk Electronic Properties of Heterojunction Devices.

PubMed

Bissig, Benjamin; Guerra-Nunez, Carlos; Carron, Romain; Nishiwaki, Shiro; La Mattina, Fabio; Pianezzi, Fabian; Losio, Paolo A; Avancini, Enrico; Reinhard, Patrick; Haass, Stefan G; Lingg, Martina; Feurer, Thomas; Utke, Ivo; Buecheler, Stephan; Tiwari, Ayodhya N

2016-10-01

Quantum efficiency measurements of state of the art Cu(In,Ga)Se 2 (CIGS) thin film solar cells reveal current losses in the near infrared spectral region. These losses can be ascribed to inadequate optical absorption or poor collection of photogenerated charge carriers. Insight on the limiting mechanism is crucial for the development of more efficient devices. The electron beam induced current measurement technique applied on device cross-sections promises an experimental access to depth resolved information about the charge carrier collection probability. Here, this technique is used to show that charge carrier collection in CIGS deposited by multistage co-evaporation at low temperature is efficient over the optically active region and collection losses are minor as compared to the optical ones. Implications on the favorable absorber design are discussed. Furthermore, it is observed that the measurement is strongly affected by cross-section surface recombination and an accurate determination of the collection efficiency is not possible. Therefore it is proposed and shown that the use of an Al 2 O 3 layer deposited onto the cleaved cross-section significantly improves the accuracy of the measurement by reducing the surface recombination. A model for the passivation mechanism is presented and the passivation concept is extended to other solar cell technologies such as CdTe and Cu 2 (Zn,Sn)(S,Se) 4 . © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

SnS2 films deposited from molecular ink as Cd-free alternative buffer layer for solar cells

NASA Astrophysics Data System (ADS)

Jariwala, Akshay; Chaudhuri, Tapas K.; Toshniwal, Aditi; Patel, Sanjay; Kheraj, Vipul; Ray, Abhijit

2018-05-01

This work investigates the potential of SnS2 as a Cd-free alternative buffer layer for CIGS solar cells. The suitability of SnS2 film as a buffer layer has been evaluated by numerical analysis using SCAPS software. A new simple method for preparation of SnS2 films by dip-coating from molecular ink is reported. The formation of SnS2 is confirmed by Raman spectroscopy. The films are smooth and shiny with roughness of 2-3 nm. The films are n-type with band gap of 2.6 eV and electrical conductivity of 10-3 S/cm.

Will chronic e-cigarette use cause lung disease?

PubMed

Rowell, Temperance R; Tarran, Robert

2015-12-15

Chronic tobacco smoking is a major cause of preventable morbidity and mortality worldwide. In the lung, tobacco smoking increases the risk of lung cancer, and also causes chronic obstructive pulmonary disease (COPD), which encompasses both emphysema and chronic bronchitis. E-cigarettes (E-Cigs), or electronic nicotine delivery systems, were developed over a decade ago and are designed to deliver nicotine without combusting tobacco. Although tobacco smoking has declined since the 1950s, E-Cig usage has increased, attracting both former tobacco smokers and never smokers. E-Cig liquids (e-liquids) contain nicotine in a glycerol/propylene glycol vehicle with flavorings, which are vaporized and inhaled. To date, neither E-Cig devices, nor e-liquids, are regulated by the Food and Drug Administration (FDA). The FDA has proposed a deeming rule, which aims to initiate legislation to regulate E-Cigs, but the timeline to take effect is uncertain. Proponents of E-Cigs say that they are safe and should not be regulated. Opposition is varied, with some opponents proposing that E-Cig usage will introduce a new generation to nicotine addiction, reversing the decline seen with tobacco smoking, or that E-Cigs generally may not be safe and will trigger diseases like tobacco. In this review, we shall discuss what is known about the effects of E-Cigs on the mammalian lung and isolated lung cells in vitro. We hope that collating this data will help illustrate gaps in the knowledge of this burgeoning field, directing researchers toward answering whether or not E-Cigs are capable of causing disease. Copyright © 2015 the American Physiological Society.

Will chronic e-cigarette use cause lung disease?

PubMed Central

Rowell, Temperance R.

2015-01-01

Chronic tobacco smoking is a major cause of preventable morbidity and mortality worldwide. In the lung, tobacco smoking increases the risk of lung cancer, and also causes chronic obstructive pulmonary disease (COPD), which encompasses both emphysema and chronic bronchitis. E-cigarettes (E-Cigs), or electronic nicotine delivery systems, were developed over a decade ago and are designed to deliver nicotine without combusting tobacco. Although tobacco smoking has declined since the 1950s, E-Cig usage has increased, attracting both former tobacco smokers and never smokers. E-Cig liquids (e-liquids) contain nicotine in a glycerol/propylene glycol vehicle with flavorings, which are vaporized and inhaled. To date, neither E-Cig devices, nor e-liquids, are regulated by the Food and Drug Administration (FDA). The FDA has proposed a deeming rule, which aims to initiate legislation to regulate E-Cigs, but the timeline to take effect is uncertain. Proponents of E-Cigs say that they are safe and should not be regulated. Opposition is varied, with some opponents proposing that E-Cig usage will introduce a new generation to nicotine addiction, reversing the decline seen with tobacco smoking, or that E-Cigs generally may not be safe and will trigger diseases like tobacco. In this review, we shall discuss what is known about the effects of E-Cigs on the mammalian lung and isolated lung cells in vitro. We hope that collating this data will help illustrate gaps in the knowledge of this burgeoning field, directing researchers toward answering whether or not E-Cigs are capable of causing disease. PMID:26408554

The AMIGA sample of isolated galaxies. XII. Revision of the isolation degree for AMIGA galaxies using the SDSS

NASA Astrophysics Data System (ADS)

Argudo-Fernández, M.; Verley, S.; Bergond, G.; Sulentic, J.; Sabater, J.; Fernández Lorenzo, M.; Leon, S.; Espada, D.; Verdes-Montenegro, L.; Santander-Vela, J. D.; Ruiz, J. E.; Sánchez-Expósito, S.

2013-12-01

Context. To understand the evolution of galaxies, it is necessary to have a reference sample where the effect of the environment is minimized and quantified. In the framework of the AMIGA project (Analysis of the interstellar Medium of Isolated GAlaxies), we present a revision of the environment for galaxies in the Catalogue of Isolated Galaxies (CIG, Karachentseva 1973, Astrof. Issledovaniia Byu. Spec. Ast. Obs., 8, 3) using the ninth data release of the Sloan Digital Sky Survey (SDSS-DR9). Aims: The aims of this study are to refine the photometric-based AMIGA sample of isolated galaxies and to provide an improvement of the quantification of the isolation degree with respect to previous works, using both photometry and spectroscopy. Methods: We developed an automatic method to search for neighbours within a projected area of 1 Mpc radius centred on each primary galaxy to revise the CIG isolation criteria introduced by Karachentseva (1973). The local number density at the fifth nearest neighbour and the tidal strength affecting the CIG galaxy were estimated to quantify the isolation degree. Results: Of the 636 CIG galaxies considered in the photometric study, 426 galaxies fulfil the CIG isolation criteria within 1 Mpc, taking into account projected neighbours. Of the 411 CIG galaxies considered in the spectroscopic study, 347 galaxies fulfil the CIG isolation criteria when a criterion about redshift difference is added. The available redshifts allow us to reject background neighbours and thus improve the photometric assessment. On average, galaxies in the AMIGA sample show lower values in the local number density and the tidal strength parameters than galaxies in denser environments such as pairs, triplets, compact groups, and clusters. Conclusions: For the first time, the environment and the isolation degree of AMIGA galaxies are quantified using digital data. The use of the SDSS database permits one to identify fainter and smaller-size satellites than in previous AMIGA works. The AMIGA sample is improved by this study, because we reduced the sample of isolated galaxies used in previous AMIGA works by about 20%. The availability of the spectroscopic data allows us to check the validity of the CIG isolation criteria, which is not fully efficient. About 50% of the neighbours considered as potential companions in the photometric study are in fact background objects. We also find that about 92% of the neighbour galaxies that show recession velocities similar to the corresponding CIG galaxy are not considered by the CIG isolation criteria as potential companions, which may have a considerable influence on the evolution of the central CIG galaxy. Full Tables 2 and 4 are only available in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/560/A9

Development and manufacture of reactive-transfer-printed CIGS photovoltaic modules

NASA Astrophysics Data System (ADS)

Eldada, Louay; Sang, Baosheng; Lu, Dingyuan; Stanbery, Billy J.

2010-09-01

In recent years, thin-film photovoltaic (PV) companies started realizing their low manufacturing cost potential, and grabbing an increasingly larger market share from multicrystalline silicon companies. Copper Indium Gallium Selenide (CIGS) is the most promising thin-film PV material, having demonstrated the highest energy conversion efficiency in both cells and modules. However, most CIGS manufacturers still face the challenge of delivering a reliable and rapid manufacturing process that can scale effectively and deliver on the promise of this material system. HelioVolt has developed a reactive transfer process for CIGS absorber formation that has the benefits of good compositional control, high-quality CIGS grains, and a fast reaction. The reactive transfer process is a two stage CIGS fabrication method. Precursor films are deposited onto substrates and reusable print plates in the first stage, while in the second stage, the CIGS layer is formed by rapid heating with Se confinement. High quality CIGS films with large grains were produced on a full-scale manufacturing line, and resulted in high-efficiency large-form-factor modules. With 14% cell efficiency and 12% module efficiency, HelioVolt started to commercialize the process on its first production line with 20 MW nameplate capacity.

Full Sputtering Deposition of Thin Film Solar Cells: A Way of Achieving High Efficiency Sustainable Tandem Cells?

NASA Astrophysics Data System (ADS)

Vilcot, J.-P.; Ayachi, B.; Aviles, T.; Miska, P.

2017-11-01

In the first part of this paper, we will show that a sputtering-based fabrication process exhibiting a low environmental footprint has been developed for the fabrication of copper indium gallium selenide (CIGS) absorbing material. Its originality lies in using room temperature sputtering in a pulsed—direct current mode of a single quaternary target followed by a post-anneal. At any stage of the process, selenium or sulfur atmosphere is used. Inert gas is used, respectively argon and a forming gas, for the deposition and annealing step, respectively. CIGS cells have been fabricated using such an absorbing layer. They exhibit an efficiency close to 12%. A tandem cell approach, using a thin film technology in conjunction with the well-established Si technology, is a promising technique, achieving cells with 30%, and higher, efficiency. Such cells are awaited, jointly with a stronger implementation of low environmental footprint technologies, as a vision for 2030. In the first section, sputtering technique has shown its ability to be developed in such a way achieving an environmentally friendly process that can be moreover compatible to be co-integrated with, for example, Si technology. In a second section, we will present a prospective discussion on the materials that can be applied to produce a sustainable approach for such a tandem cell configuration.

Tobacco toxicant exposure in cigarette smokers who use or do not use other tobacco products.

PubMed

Nollen, Nicole L; Mayo, Matthew S; Clark, Lauren; Cox, Lisa Sanderson; Khariwala, Samir S; Pulvers, Kim; Benowitz, Neal L; Ahluwalia, Jasjit S

2017-10-01

Non-cigarette other tobacco products (OTP; e.g., cigarillos, little cigars) are typically used in combination with cigarettes, but limited data exists on the tobacco toxicant exposure profiles of dual cigarette-OTP (Cig-OTP) users. This study examined biomarkers of nicotine and carcinogen exposure in cigarette smokers who used or did not use OTP. 111 Cig-OTP and 111 cigarette only (Cig Only) users who smoked equivalent cigarettes per day were matched on age (< 40, >=40), race (African American, White), and gender. Participants reported past 7-day daily use of cigarettes and OTP and provided urine for nicotine, cotinine, total nicotine equivalents (TNE) and total NNAL concentrations. Cig-OTP users reported greater past 7-day tobacco use (15.9 versus 13.0 products/day, p<0.01) but had significantly lower creatinine-normalized nicotine (606 versus 1301ng/mg), cotinine (1063 versus 2125ng/mg), TNE (28 versus 57 nmol/mg) and NNAL (251 versus 343pg/mg) than Cig Only users (p<0.001). Cig-OTP users had lower levels of nicotine and metabolites of a lung carcinogen relative to Cig-Only users, but concentrations of toxicants among Cig-OTP users were still at levels that place smokers at great risk from the detrimental health effects of smoking. Our study finds that nicotine and carcinogen exposure in Cig-OTP users are lower compared to cigarette only users, but still likely to be associated with substantial harm. A better understanding of why toxicant levels may be lower in Cig-OTP is an important area for future study. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of a questionnaire for assessing dependence on electronic cigarettes among a large sample of ex-smoking E-cigarette users.

PubMed

Foulds, Jonathan; Veldheer, Susan; Yingst, Jessica; Hrabovsky, Shari; Wilson, Stephen J; Nichols, Travis T; Eissenberg, Thomas

2015-02-01

Electronic cigarettes (e-cigs) are becoming increasingly popular, but little is known about their dependence potential. This study aimed to assess ratings of dependence on electronic cigarettes and retrospectively compare them with rated dependence on tobacco cigarettes among a large sample of ex-smokers who switched to e-cigs. A total of 3,609 current users of e-cigs who were ex-cigarette smokers completed a 158-item online survey about their e-cig use, including 10 items designed to assess their previous dependence on cigarettes and 10 almost identical items, worded to assess their current dependence on e-cigs (range 0-20). Scores on the 10-item Penn State (PS) Cigarette Dependence Index were significantly higher than on the comparable PS Electronic Cigarette Dependence Index (14.5 vs. 8.1, p < .0001). In multivariate analysis, those who had used e-cigs longer had higher e-cig dependence scores, as did those using more advanced e-cigs that were larger than a cigarette and had a manual button. Those using zero nicotine liquid had significantly lower e-cig dependence scores than those using 1-12 mg/ml, who scored significantly lower than those using 13 or greater mg/ml nicotine liquid (p < .003). Current e-cigarette users reported being less dependent on e-cigarettes than they retrospectively reported having been dependent on cigarettes prior to switching. E-cig dependence appears to vary by product characteristics and liquid nicotine concentration, and it may increase over time. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Electronic cigarette aerosols and copper nanoparticles induce mitochondrial stress and promote DNA fragmentation in lung fibroblasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lerner, Chad A.; Rutagarama, Pierrot; Ahmad, Tanveer

Oxidants or nanoparticles have recently been identified as constituents of aerosols released from various styles of electronic cigarettes (E-cigs). Cells in the lung may be directly exposed to these constituents and harbor reactive properties capable of incurring acute cell injury. Our results show mitochondria are sensitive to both E-cig aerosols and aerosol containing copper nanoparticles when exposed to human lung fibroblasts (HFL-1) using an Air-Liquid Interface culture system, evident by elevated levels of mitochondrial ROS (mtROS). Increased mtROS after aerosol exposure is associated with reduced stability of OxPhos electron transport chain (ETC) complex IV subunit and nuclear DNA fragmentation. Increasedmore » levels of IL-8 and IL-6 in HFL-1 conditioned media were also observed. These findings reveal both mitochondrial, genotoxic, and inflammatory stresses are features of direct cell exposure to E-cig aerosols which are ensued by inflammatory duress, raising a concern on deleterious effect of vaping. - Graphical abstract: Oxidants and possibly reactive properties of metal particles in E-cig aerosols impart mitochondrial oxidative stress and DNA damage. These biological effects accompany inflammatory response which may raise concern regarding long term E-cig use. Mitochondria may be particularly sensitive to reactive properties of E-cig aerosols in addition to the potential for them to induce genotoxic stress by generating increased ROS. - Highlights: • Mitochondria are sensitive to both E-cig aerosols and metal nanoparticles. • Increased mtROS by E-cig aerosol is associated with disrupted mitochondrial energy. • E-cig causes nuclear DNA fragmentation. • E-cig aerosols induce pro-inflammatory response in human fibroblasts.« less

Influence of carrier concentration on the performance of CIAS solar cell

NASA Astrophysics Data System (ADS)

Patel, Kinjal; Ray, Jaymin

2018-05-01

Photovoltaic research has moved beyond the use of single crystalline materials such as Group IV elemental Si and Group III-V compounds like GaAs to much more complex compounds of the Group I-III-VI2 with chalcopyrite structure. The ternary ABC2 chalcopyrites (A=Cu; B=In, Ga or Al; C= S, Se or Te) form a large group of semiconducting materials with diverse structural and electrical properties. These materials are attractive for thin film photovoltaic application for a number of reasons. The bandgap of CuInSe2 is relatively low, 1.04 eV, but it can be adjusted to better match the solar spectrum either by substituting part of In by Ga or part of Se by S. Most reported and popular Cu(In,Ga)Se2 (CIGS) is one of its derivative. Efficiency of the CIGS devices with Eg >1.3 eV is reduced by the degradation of the electronic properties of the absorber leading to losses in the fill-factor and the open-circuit voltage. Alternatively, the performance can be improved by the addition of Al to form CuInAlSe2 (CIAS) absorber layers with an increase in the bandgap energy, which matches closely with the solar spectrum. In the present work an effort was made in the direction of improving the conversion efficiency by studying the influence of carrier concentration. SCAPS simulation program is used to simulate the CIAS structure numerically. The obtained results intended the significant variation in the values of conversion efficiency. Variation in the efficiency can be considered because of the relation optical absorption and carrier concentration. Observed highest efficiency is 10 %, which can be further improved by considering actual parameters of the device as well as the operating condition.

[Focus on electronic cigarettes].

PubMed

Tinghino, Biagio; Pacifici, Roberta; Di Pucchio, Alessandra; Palmi, Ilaria; Solimini, Renata; Faggiano, Fabrizio; Gorini, Giuseppe

2013-01-01

There is no clear regulation on electronic cigarettes (e-cig); their health effects are not yet fully investigated and there is insufficient standardisation and quality control of the product. Moreover, the e-cig could be a gateway for young people to nicotine addiction and traditional cigarette smoking. In Italy, the Ministry of Health banned the sale of e-cig with nicotine firstly to adolescents aged <16 years, then to people <18 years. Until further scientific evidence is available, it is mandatory to regulate the production and marketing of e-cigs, to make them less attractive, to forbid their use in enclosed areas, and prevent them from being promoted. E-cigs, however, seem to be much less dangerous than traditional cigarettes, although the few studies conducted are not sufficient to demonstrate either a clear therapeutic efficacy of e-cig or their total harmlessness. If e-cig had a known content, were made according to clear rules and in certified laboratories, without toxic substances, it could be used to help heavy smokers to quit, or at least to reduce smoking habits. There is a large proportion of smokers who are unable to quit. The revision of the European Directive (the proposal is being evaluated and we are waiting for its final approval) on tobacco recommends free sale for a minority of e-cigs only, those with a nicotine content <4 mg/ml. This will be difficult, considering that the business is just the free sale of e-cig and the much more dangerous tobacco cigarettes are still sold without any restriction.

Polycrystalline Thin Film Photovoltaics: Research, Development, and Technologies: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ullal, H. S.; Zweibel, K.; von Roedern, B.

2002-05-01

II-VI binary thin-film solar cells based on cadmium telluride (CdTe) and I-III-VI ternary thin-film solar cells based on copper indium diselenide (CIS) and related materials have been the subject of intense research and development in the past few years. Substantial progress has been made thus far in the area of materials research, device fabrication, and technology development, and numerous applications based on CdTe and CIS have been deployed worldwide. World record efficiency of 16.5% has been achieved by NREL scientists for a thin-film CdTe solar cell using a modified device structure. Also, NREL scientists achieved world-record efficiency of 21.1% formore » a thin-film CIGS solar cell under a 14X concentration and AM1.5 global spectrum. When measured under a AM1.5 direct spectrum, the efficiency increases to 21.5%. Pathways for achieving 25% efficiency for tandem polycrystalline thin-film solar cells are elucidated. R&D issues relating to CdTe and CIS are reported in this paper, such as contact stability and accelerated life testing in CdTe, and effects of moisture ingress in thin-film CIS devices. Substantial technology development is currently under way, with various groups reporting power module efficiencies in the range of 7.0% to 12.1% and power output of 40.0 to 92.5 W. A number of lessons learned during the scale-up activities of the technology development for fabrication of thin-film power modules are discussed. The major global players actively involved in the technology development and commercialization efforts using both rigid and flexible power modules are highlighted.« less

Solution-deposited CIGS thin films for ultra-low-cost photovoltaics

NASA Astrophysics Data System (ADS)

Eldada, Louay A.; Hersh, Peter; Stanbery, Billy J.

2010-09-01

We describe the production of photovoltaic modules with high-quality large-grain copper indium gallium selenide (CIGS) thin films obtained with the unique combination of low-cost ink-based precursors and a reactive transfer printing method. The proprietary metal-organic inks contain a variety of soluble Cu-, In- and Ga- multinary selenide materials; they are called metal-organic decomposition (MOD) precursors, as they are designed to decompose into the desired precursors. Reactive transfer is a two-stage process that produces CIGS through the chemical reaction between two separate precursor films, one deposited on the substrate and the other on a printing plate in the first stage. In the second stage, these precursors are rapidly reacted together under pressure in the presence of heat. The use of two independent thin films provides the benefits of independent composition and flexible deposition technique optimization, and eliminates pre-reaction prior to the synthesis of CIGS. In a few minutes, the process produces high quality CIGS films, with large grains on the order of several microns, and preferred crystallographic orientation, as confirmed by compositional and structural analysis by XRF, SIMS, SEM and XRD. Cell efficiencies of 14% and module efficiencies of 12% were achieved using this method. The atmospheric deposition processes include slot die extrusion coating, ultrasonic atomization spraying, pneumatic atomization spraying, inkjet printing, direct writing, and screen printing, and provide low capital equipment cost, low thermal budget, and high throughput.

[Electronic cigarettes: A therapeutic tool, a social phenomenon or a business?].

PubMed

Berlin, I

2015-06-01

Smoking is the first avoidable cause of morbidity and mortality. It is estimated that there were around 14 million smokers in France in 2012 and that smoking results in 70,000 deaths per year. All types of interventions reducing with efficacy the incidence and prevalence of smoking are to consider in prolonging life expectancy. Electronic cigarettes (e.cig.) are a social phenomenon but they also are a system delivering pharmacologically active substances; their use concerns today several millions of individuals in France. By this fact, it became important for clinical practitioners to acquire some knowledge about e. cig. Most of the e.cig. contains nicotine, thus, e.cig. are now called in the medical literature as electronic nicotine delivery system (ENDS). It is highly plausible that ENDS, which are, as of today, consumer products and not health products, deliver nicotine with a good bioavailability and could, if largely used, help to reduce smoking prevalence. However, because of current lack of regulations, as of today, the risk/benefit ratio of ENDS as an aid to help smokers quit and their adverse effect profile cannot be established. It is of public health responsibility to promote evidence based knowledge about e.cig. to know with confidence their risk/benefit ratio. Copyright © 2014 Société nationale française de médecine interne (SNFMI). Published by Elsevier SAS. All rights reserved.

Fabrication of CIGS Films by Electrodeposition Method for Photovoltaic Cells

NASA Astrophysics Data System (ADS)

Lee, Hyunju; Yoon, Hyukjoo; Ji, Changwook; Lee, Dongyun; Lee, Jae-Ho; Yun, Jae-Ho; Kim, Yangdo

2012-12-01

Cu(InGa)Se2 (CIGS) thin films were fabricated by electrochemical deposition in a single bath containing Cu, In, Ga, and Se ions. The electrolyte was prepared by dissolving CuCl2, InCl3, GaCl3, H2SeO3, and LiCl in deionized water. The potentiostatic deposition process was achieved by applying a voltage ranging from -0.5 V to -0.8 V versus Ag/AgCl. The effects of different chemical bath concentrations on the film composition and morphology were investigated. Stoichiometric CIGS film composition could be achieved by controlling the chemical compositions of the bath and the voltage. Gelatin was added to the solution to improve the surface and microstructures of the CIGS film. The as-deposited films were annealed at 500°C in Ar atmosphere for crystallization. The structural, morphological, and compositional properties of the CIGS thin films before and after annealing were examined by x-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. This study showed that the composition of the CIGS films is dependent on the bath concentration, whereas the applied potential had relatively less effect on the CIGS film composition. In addition, the use of gelatin helped in the fabrication of crack-free CIGS thin films with greatly improved surface morphology.

[Smoking fewer cigarettes per day may determine a significant risk reduction in developing smoking attributable diseases? Is there a risk reduction for e-cigarette users?].

PubMed

Pieri, Luca; Chellini, Elisabetta; Gorini, Giuseppe

2014-01-01

Among Italian smokers--about 10 millions in 2013--about 600,000 began using electronic cigarettes (e-cigs) in last years. About 10% of e-cig users quitted smoking tobacco, whereas the 90% was dual users. Among them, about three out of four decreased the number of cigarettes smoked per day (cig/day), but did not quit. How many fewer cigarettes a smoker has to smoke to obtain significant health benefits? Is there a threshold? In order to observe a significant 27% reduction in the risk of developing lung cancer, a smoker must reduce the number of cig/day by at least 50%, while for the other smoking-related diseases (acute myocardial infarction - AMI, stroke, chronic obstructive pulmonary diseases), halving the number of cig/day did not drive to a significant risk reduction. Even smoking 5 cig/day increases the risk of AMI, whereas it significantly lowers the risk of lung cancer. Obviously, quitting smoking is the best choice to highly reduce risks for all smoking-related diseases. Therefore, in order to achieve significant risk reductions, e-cig users should quit smoking as first choice, or, if they feel it is impossible to them, reduce the consumption of traditional cigarettes to less than 5 cig/day.

The Computational Infrastructure for Geodynamics: An Example of Software Curation and Citation in the Geodynamics Community

NASA Astrophysics Data System (ADS)

Hwang, L.; Kellogg, L. H.

2017-12-01

Curation of software promotes discoverability and accessibility and works hand in hand with scholarly citation to ascribe value to, and provide recognition for software development. To meet this challenge, the Computational Infrastructure for Geodynamics (CIG) maintains a community repository built on custom and open tools to promote discovery, access, identification, credit, and provenance of research software for the geodynamics community. CIG (geodynamics.org) originated from recognition of the tremendous effort required to develop sound software and the need to reduce duplication of effort and to sustain community codes. CIG curates software across 6 domains and has developed and follows software best practices that include establishing test cases, documentation, and a citable publication for each software package. CIG software landing web pages provide access to current and past releases; many are also accessible through the CIG community repository on github. CIG has now developed abc - attribution builder for citation to enable software users to give credit to software developers. abc uses zenodo as an archive and as the mechanism to obtain a unique identifier (DOI) for scientific software. To assemble the metadata, we searched the software's documentation and research publications and then requested the primary developers to verify. In this process, we have learned that each development community approaches software attribution differently. The metadata gathered is based on guidelines established by groups such as FORCE11 and OntoSoft. The rollout of abc is gradual as developers are forward-looking, rarely willing to go back and archive prior releases in zenodo. Going forward all actively developed packages will utilize the zenodo and github integration to automate the archival process when a new release is issued. How to handle legacy software, multi-authored libraries, and assigning roles to software remain open issues.

Effectiveness of the electronic cigarette: An eight-week Flemish study with six-month follow-up on smoking reduction, craving and experienced benefits and complaints.

PubMed

Adriaens, Karolien; Van Gucht, Dinska; Declerck, Paul; Baeyens, Frank

2014-10-29

Smoking reduction remains a pivotal issue in public health policy, but quit rates obtained with traditional quit-smoking therapies remain disappointingly low. Tobacco Harm Reduction (THR), aiming at less harmful ways of consuming nicotine, may provide a more effective alternative. One promising candidate for THR are electronic cigarettes (e-cigs). The aim of this study was to investigate the efficacy of second-generation e-cigs both in terms of acute craving-reduction in the lab and in terms of smoking reduction and experienced benefits/complaints in an eight-month Randomized Controlled Trial (RCT). RCT with three arms. Participants (N = 48) unwilling to quit smoking were randomized into two e-cig groups and one control group. During three lab sessions (over two months) participants, who had been abstinent for four hours, vaped/smoked for five minutes, after which we monitored the effect on craving and withdrawal symptoms. eCO and saliva cotinine levels were also measured. In between lab sessions, participants in the e-cig groups could use e-cigs or smoke ad libitum, whereas the control group could only smoke. After the lab sessions, the control group also received an e-cig. The RCT included several questionnaires, which repeatedly monitored the effect of ad libitum e-cig use on the use of tobacco cigarettes and the experienced benefits/complaints up to six months after the last lab session. From the first lab session on, e-cig use after four hours of abstinence resulted in a reduction in cigarette craving which was of the same magnitude as when a cigarette was smoked, while eCO was unaffected. After two months, we observed that 34% of the e-cig groups had stopped smoking tobacco cigarettes, versus 0% of the control group. After five months, the e-cig groups demonstrated a total quit-rate of 37%, whereas the control group showed a quit rate of 38% three months after initiating e-cig use. At the end of the eight-month study, 19% of the e-cig groups and 25% of the control group were totally abstinent from smoking, while an overall reduction of 60% in the number of cigarettes smoked per day was observed (compared to intake). eCO levels decreased, whereas cotinine levels were the same in all groups at each moment of measurement. Reported benefits far outweighed the reported complaints. In a series of controlled lab sessions with e-cig naïve tobacco smokers, second generation e-cigs were shown to be immediately and highly effective in reducing abstinence induced cigarette craving and withdrawal symptoms, while not resulting in increases in eCO. Remarkable (>50 pc) eight-month reductions in, or complete abstinence from tobacco smoking was achieved with the e-cig in almost half (44%) of the participants.

Successful Nicotine Intake in Medical Assisted Use of E-Cigarettes: A Pilot Study.

PubMed

Pacifici, Roberta; Pichini, Simona; Graziano, Silvia; Pellegrini, Manuela; Massaro, Giuseppina; Beatrice, Fabio

2015-07-08

The electronic cigarette (e-cig) has gained popularity as an aid in smoking cessation programs mainly because it maintains the gestures and rituals of tobacco smoking. However, it has been shown in inexperienced e-cig users that ineffective nicotine delivery can cause tobacco craving that could be responsible for unsuccessful smoking reduction/cessation. Moreover, the incorrect use of an e-cig could also led to potential nicotine overdosage and intoxication. Medically assisted training on the proper use of an e-cig plus behavioral support for tobacco dependence could be a pivotal step in avoiding both issues. We performed an eight-month pilot study of adult smokers who started e-cig use after receiving a multi-component medically assisted training program with monitoring of nicotine intake as a biomarker of correct e-cig use. Participants were tested during follow-up for breath carbon monoxide (CO), plasma cotinine and trans-3'-hydroxycotinine, and number of tobacco cigarettes smoked. At the end of the first, fourth, and eighth month of follow-up, 91.1, 73.5, and 76.5% of participants respectively were e-cig users ('only e-cig' and 'dual users'). They showed no significant variation in plasma cotinine and trans-3'-hydroxycotinine with respect to the start of the study when they smoked only tobacco cigarettes, but a significant reduction in breath CO. The proposed medically assisted training program of e-cig use led to a successful nicotine intake, lack of typical cigarette craving and overdosage symptoms and a significant decrease in the biomarker of cigarette combustion products.

Using features of Arden Syntax with object-oriented medical data models for guideline modeling.

PubMed

Peleg, M; Ogunyemi, O; Tu, S; Boxwala, A A; Zeng, Q; Greenes, R A; Shortliffe, E H

2001-01-01

Computer-interpretable guidelines (CIGs) can deliver patient-specific decision support at the point of care. CIGs base their recommendations on eligibility and decision criteria that relate medical concepts to patient data. CIG models use expression languages for specifying these criteria, and define models for medical data to which the expressions can refer. In developing version 3 of the GuideLine Interchange Format (GLIF3), we used existing standards as the medical data model and expression language. We investigated the object-oriented HL7 Reference Information Model (RIM) as a default data model. We developed an expression language, called GEL, based on Arden Syntax's logic grammar. Together with other GLIF constructs, GEL reconciles incompatibilities between the data models of Arden Syntax and the HL7 RIM. These incompatibilities include Arden's lack of support for complex data types and time intervals, and the mismatch between Arden's single primary time and multiple time attributes of the HL7 RIM.

Effects of using electronic cigarettes on nicotine delivery and cardiovascular function in comparison with regular cigarettes.

PubMed

Yan, X Sherwin; D'Ruiz, Carl

2015-02-01

The development of electronic cigarettes (e-cigs) has the potential to offer a less harmful alternative for tobacco users. This clinical study was designed to characterize e-cig users' exposure to nicotine, and to investigate the acute effects of e-cigs on the hemodynamic measurements (blood pressure and heart rate) in comparison with the effects of regular smoking. Five e-cigs and one Marlboro® cigarette were randomized for twenty-three participants under two exposure scenarios from Day 1 to Day 11: half-hour controlled administration and one hour ad lib use. The nicotine plasma concentrations after 1.5h of product use (C90) were significantly lower in the users of e-cigs than of Marlboro® cigarettes. The combination of glycerin and propylene glycol as the vehicle facilitated delivery of more nicotine than glycerin alone. The heart rate, systolic and diastolic blood pressure were significantly elevated after use of Marlboro® cigarettes, but the elevation was less after use of most of the e-cigs. Use of e-cigs had no impact on the exhaled CO levels, whereas the Marlboro® cigarette significantly increased the exhaled CO more than 8 times above the baseline. In conclusion, e-cigs could be a less harmful alternative for tobacco users. Copyright © 2014 Elsevier Inc. All rights reserved.

E-cigarette knowledge, attitudes, and use in opioid dependent smokers.

PubMed

Stein, Michael D; Caviness, Celeste M; Grimone, Kristin; Audet, Daniel; Borges, Allison; Anderson, Bradley J

2015-05-01

Individuals in treatment for opioid dependence have smoking rates 3-5 times greater than the U.S. prevalence rate. Traditional smoking cessation strategies have been ineffective in this population. Novel approaches are needed as well as harm reduction avenues. E-cigarettes (e-cigs) may provide such a novel harm reduction and cessation opportunity, but little is known about the knowledge of, attitudes about, and usage of e-cigs in opioid dependent smokers. The current study enrolled 315 opioid dependent smokers (164 methadone, 151 buprenorphine), treated in the same health system in Fall River, Massachusetts. The sample was 49.7% male and 85.1% non-Latino White. Overall 98.7% had heard of e-cigs, 73.0% had ever tried e-cigs, and 33.8% had used e-cigs in the past 30 days. The most common reasons for use were curiosity (41.4%) and to quit all nicotine (26.0%). The proportion of opioid dependent smokers that had ever tried e-cigs and used them in the past month was substantially greater than that found in recent general population surveys. While e-cigs have been used to quit smoking, how to optimize their utility as a cessation tool remains undefined. E-cigs should be a part of smoking cessation discussions with this vulnerable, difficult-to-treat population. Copyright © 2015 Elsevier Inc. All rights reserved.

E-Cigs, Menthol & Dip

MedlinePlus

... are different. Find out why any product with nicotine can be addictive and bad for your health. What We Know About Electronic Cigarettes (E-cigarettes) Some people use e-cigs to quit smoking. But there is still much about e-cigs that's unknown. Read ...

Multi-Material Front Contact for 19% Thin Film Solar Cells.

PubMed

van Deelen, Joop; Tezsevin, Yasemin; Barink, Marco

2016-02-06

The trade-off between transmittance and conductivity of the front contact material poses a bottleneck for thin film solar panels. Normally, the front contact material is a metal oxide and the optimal cell configuration and panel efficiency were determined for various band gap materials, representing Cu(In,Ga)Se₂ (CIGS), CdTe and high band gap perovskites. Supplementing the metal oxide with a metallic copper grid improves the performance of the front contact and aims to increase the efficiency. Various front contact designs with and without a metallic finger grid were calculated with a variation of the transparent conductive oxide (TCO) sheet resistance, scribing area, cell length, and finger dimensions. In addition, the contact resistance and illumination power were also assessed and the optimal thin film solar panel design was determined. Adding a metallic finger grid on a TCO gives a higher solar cell efficiency and this also enables longer cell lengths. However, contact resistance between the metal and the TCO material can reduce the efficiency benefit somewhat.

Differences between Dual Users and Switchers Center around Vaping Behavior and Its Experiences Rather than Beliefs and Attitudes

PubMed Central

2017-01-01

(1) Background: Many smokers completely switch to vaping (switchers), whereas others use e-cigarettes (e-cigs) alongside tobacco cigarettes (dual users). To the extent that dual users substantially lower the number of cigarettes, they will reduce health risks from smoking. However, from a medical point of view, exclusive vaping is preferable to dual use; (2) Methods: Using an online questionnaire we assessed behavioral, cognitive and attitudinal aspects of e-cig use in smoking and ex-smoking vapers; (3) Results: Our sample consisted of 19% dual users and 81% switchers. Before e-cig initiation, both groups smoked on average 22 cigarettes per day (CPD). After e-cig initiation, dual users decreased tobacco consumption by 82% and were low-to-moderately cigarette dependent. Both groups had been vaping for on average 22 months, were highly e-cig dependent, used state-of-the-art e-cigs, nicotine concentrations of 4–8 mg/mL and often flavors other than tobacco. Dual users used substantially less e-liquid per week than switchers but reported a similar number of puffs/day, experienced less e-cig efficacy, more practical problems, more negative and less positive consequences, and endorsed smoking reduction (rather than quitting) as a more important reason to start vaping. For both groups, e-cig risk perception was low and little stigmatization was experienced. Dual users preferred tobacco cigarettes in stressful situations and when rapid nicotine uptake is required. E-cigs were preferred where cigarettes are prohibited and to reduce second-hand smoke; (4) Conclusions: Differences between dual users and switchers center around variables proximal to the vaping behavior and its experienced effects rather than hinging on more general vaping-related beliefs and attitudes. PMID:29295483

Identification and Validation of Novel Hedgehog-Responsive Enhancers Predicted by Computational Analysis of Ci/Gli Binding Site Density

PubMed Central

Richards, Neil; Parker, David S.; Johnson, Lisa A.; Allen, Benjamin L.; Barolo, Scott; Gumucio, Deborah L.

2015-01-01

The Hedgehog (Hh) signaling pathway directs a multitude of cellular responses during embryogenesis and adult tissue homeostasis. Stimulation of the pathway results in activation of Hh target genes by the transcription factor Ci/Gli, which binds to specific motifs in genomic enhancers. In Drosophila, only a few enhancers (patched, decapentaplegic, wingless, stripe, knot, hairy, orthodenticle) have been shown by in vivo functional assays to depend on direct Ci/Gli regulation. All but one (orthodenticle) contain more than one Ci/Gli site, prompting us to directly test whether homotypic clustering of Ci/Gli binding sites is sufficient to define a Hh-regulated enhancer. We therefore developed a computational algorithm to identify Ci/Gli clusters that are enriched over random expectation, within a given region of the genome. Candidate genomic regions containing Ci/Gli clusters were functionally tested in chicken neural tube electroporation assays and in transgenic flies. Of the 22 Ci/Gli clusters tested, seven novel enhancers (and the previously known patched enhancer) were identified as Hh-responsive and Ci/Gli-dependent in one or both of these assays, including: Cuticular protein 100A (Cpr100A); invected (inv), which encodes an engrailed-related transcription factor expressed at the anterior/posterior wing disc boundary; roadkill (rdx), the fly homolog of vertebrate Spop; the segment polarity gene gooseberry (gsb); and two previously untested regions of the Hh receptor-encoding patched (ptc) gene. We conclude that homotypic Ci/Gli clustering is not sufficient information to ensure Hh-responsiveness; however, it can provide a clue for enhancer recognition within putative Hedgehog target gene loci. PMID:26710299

Differences between Dual Users and Switchers Center around Vaping Behavior and Its Experiences Rather than Beliefs and Attitudes.

PubMed

Adriaens, Karolien; Van Gucht, Dinska; Baeyens, Frank

2017-12-23

(1) Background: Many smokers completely switch to vaping (switchers), whereas others use e-cigarettes (e-cigs) alongside tobacco cigarettes (dual users). To the extent that dual users substantially lower the number of cigarettes, they will reduce health risks from smoking. However, from a medical point of view, exclusive vaping is preferable to dual use; (2) Methods: Using an online questionnaire we assessed behavioral, cognitive and attitudinal aspects of e-cig use in smoking and ex-smoking vapers; (3) Results: Our sample consisted of 19% dual users and 81% switchers. Before e-cig initiation, both groups smoked on average 22 cigarettes per day (CPD). After e-cig initiation, dual users decreased tobacco consumption by 82% and were low-to-moderately cigarette dependent. Both groups had been vaping for on average 22 months, were highly e-cig dependent, used state-of-the-art e-cigs, nicotine concentrations of 4-8 mg/mL and often flavors other than tobacco. Dual users used substantially less e-liquid per week than switchers but reported a similar number of puffs/day, experienced less e-cig efficacy, more practical problems, more negative and less positive consequences, and endorsed smoking reduction (rather than quitting) as a more important reason to start vaping. For both groups, e-cig risk perception was low and little stigmatization was experienced. Dual users preferred tobacco cigarettes in stressful situations and when rapid nicotine uptake is required. E-cigs were preferred where cigarettes are prohibited and to reduce second-hand smoke; (4) Conclusions: Differences between dual users and switchers center around variables proximal to the vaping behavior and its experienced effects rather than hinging on more general vaping-related beliefs and attitudes.

Large magnetoresistance in Heusler-alloy-based epitaxial magnetic junctions with semiconducting Cu(In{sub 0.8}Ga{sub 0.2})Se{sub 2} spacer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasai, S.; Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako 351-0198; Takahashi, Y. K.

2016-07-18

We investigated the structure and magneto-transport properties of magnetic junctions using a Co{sub 2}Fe(Ga{sub 0.5}Ge{sub 0.5}) Heusler alloy as ferromagnetic electrodes and a Cu(In{sub 0.8}Ga{sub 0.2})Se{sub 2} (CIGS) semiconductor as spacers. Owing to the semiconducting nature of the CIGS spacer, large magnetoresistance (MR) ratios of 40% at room temperature and 100% at 8 K were obtained for low resistance-area product (RA) values between 0.3 and 3 Ω μm{sup 2}. Transmission electron microscopy observations confirmed the fully epitaxial growth of the chalcopyrite CIGS layer, and the temperature dependence of RA indicated that the large MR was due to spin dependent tunneling.

Theoretical Analysis of Two Novel Hybrid Thermoelectric-Photovoltaic Systems Based on Cu₂ZnSnS₄ Solar Cells.

PubMed

Lorenzi, Bruno; Contento, Gaetano; Sabatelli, Vincenzo; Rizzo, Antonella; Narducci, Dario

2017-03-01

The development and commercialization of Photovoltaic (PV) cells with good cost-efficiency trade-off not using critical raw materials (CRMs) is one of the strategies chosen by the European Community (EC) to address the Energy Roadmap 2050. In this context Cu2ZnSnS4 (CZTS) solar cells are attracting a major interest since they have the potential to combine low price with relatively high conversion efficiencies. Although a ≈9% lab scale efficiency has already been reported for CZTS this technology is still far from being competitive in terms of cost per peak-power (€/Wp) with other common materials. One possible near-future solution to increase the CZTS competiveness comes from thermoelectrics. Actually it has already been shown that Hybrid Thermoelectric-Photovoltaic Systems (HTEPVs) based on CIGS, another kesterite very similar to CZTS, can lead to a significant efficiency improvement. However it has been also clarified how the optimal hybridization strategy cannot come from the simple coupling of solar cells with commercial TEGs, but special layouts have to be implemented. Furthermore, since solar cell performances are well known to decrease with temperature, thermal decoupling strategies of the PV and TEG sections have to be taken. To address these issues, we developed a model for two different HTEPV solutions, both coupled with CZTS solar cells. In the first case we considered a Thermally-Coupled HTEPV device (TC-HTEPV) in which the TEG is placed underneath the solar cell and in thermal contact with it. The second system consists instead of an Optically-Coupled but thermally decoupled device (OC-HTEPV) in which part of the solar spectrum is focused by a non-imaging optical concentrator on the TEG hot side. For both solutions the model returns conversion efficiencies higher than that of the CZTS solar cell alone. Specifically, increases of ≈30% are predicted for both kind of systems considered.

7 CFR 1466.27 - Conservation Innovation Grants (CIG).

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Conservation Innovation Grants (CIG). 1466.27 Section... PROGRAM Contracts and Payments § 1466.27 Conservation Innovation Grants (CIG). (a) Definitions. In.... (6) Project Director means the individual responsible for the technical direction and management of...

Functional imaging of photovoltaic materials

NASA Astrophysics Data System (ADS)

Leite, Marina

For the past two decades, extensive efforts have been made to increase the short-circuit current (Jsc) of non-epitaxial solar cells to achieve higher efficiency devices. Yet, improvements in the overall device performance are still limited by the open-circuit voltage (Voc). We address this critical limiting factor of all promising materials for photovoltaics by realizing a novel nanoscale imaging platform with unprecedented spatial resolution (<100 nm), based on a variant of Kelvin-probe force microscopy. We mapped the local Voc of a variety of inorganic materials, and measured local changes >150 mV in CIGS, not resolved by conventional electrical measurements. To identify the origin of the instability frequently observed in perovskite solar cells, we leveraged our recently developed method to scan one frame in 16 seconds to spatially and temporally resolve their photo-voltage. Surprisingly, we observed local and reversible changes in the Voc of the devices upon post-illumination treatments. Our innovative functional imaging is non destructive and can be applied to other optoelectronic devices, such as LEDs and photodetectors. The author acknowledge APS and NSF (Award # 16-10833) for funding.

Outdoor measurements of a photovoltaic system using diffractive spectrum-splitting and concentration

DOE PAGES

Mohammad, N.; Schulz, M.; Wang, P.; ...

2016-09-16

In a single-bandgap absorber, photons having energy less than the bandgap are not absorbed, while those having energy larger than the bandgap lose the excess energy via thermalization. We present outdoor measurements of a photovoltaic system that overcomes these losses via spectrum splitting and concentration using a planar diffractive optic. The system was comprised of the diffractive optic coupled with GaInP and CIGS solar cells. The optic provides a geometric concentration of 3X for each solar cell. It is easily fabricated by single-step grayscale lithography and it is ultra-thin with a maximum thickness of only 2.5μm. Electrical measurements under directmore » sunlight demonstrated an increase of ~25% in total output power compared to the reference case without spectrum splitting and concentration. Since different bandgaps are in the same plane, the proposed photovoltaic system successfully circumvents the lattice-matching and current-matching issues in conventional tandem multi-junction solar cells. As a result, this system is also tolerant to solar spectrum variation and fill-factor degradation of constitutive solar cells.« less

Outdoor measurements of a photovoltaic system using diffractive spectrum-splitting and concentration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohammad, N.; Schulz, M.; Wang, P.

In a single-bandgap absorber, photons having energy less than the bandgap are not absorbed, while those having energy larger than the bandgap lose the excess energy via thermalization. We present outdoor measurements of a photovoltaic system that overcomes these losses via spectrum splitting and concentration using a planar diffractive optic. The system was comprised of the diffractive optic coupled with GaInP and CIGS solar cells. The optic provides a geometric concentration of 3X for each solar cell. It is easily fabricated by single-step grayscale lithography and it is ultra-thin with a maximum thickness of only 2.5μm. Electrical measurements under directmore » sunlight demonstrated an increase of ~25% in total output power compared to the reference case without spectrum splitting and concentration. Since different bandgaps are in the same plane, the proposed photovoltaic system successfully circumvents the lattice-matching and current-matching issues in conventional tandem multi-junction solar cells. As a result, this system is also tolerant to solar spectrum variation and fill-factor degradation of constitutive solar cells.« less

Identification and Analysis of Partial Shading Breakdown Sites in CuIn xGa (1-x)Se 2 Modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmiotti, Elizabeth; Johnston, Steven; Gerber, Andreas

In this paper, CuIn xGa (1-x) (CIGS) mini-modules are stressed under reverse bias, resembling partial shading conditions, to predict and characterize where failures occur. Partial shading can cause permanent damage in the form of 'wormlike' defects on thin-film modules due to thermal runaway. This results in module-scale power losses. We have used dark lock-in thermography (DLIT) to spatially observe localized heating when reverse-bias breakdown occurs on various CIGS mini-modules. For better understanding of how and where these defects originated and propagated, we have developed techniques where the current is limited during reverse-bias stressing. This allows for DLIT-based detection and detailedmore » studying of the region where breakdown is initiated before thermal runaway leads to permanent damage. Statistics of breakdown sites using current-limited conditions has allowed for reasonable identification of the as-grown defects where permanent breakdown will likely originate. Scanning electron microscope results and wormlike defect analysis show that breakdown originates in defects such as small pits, craters, or cracks in the CIGS layer, and the wormlike defects propagate near the top CIGS interface.« less

Identification and Analysis of Partial Shading Breakdown Sites in CuIn xGa (1-x)Se 2 Modules

DOE PAGES

Palmiotti, Elizabeth; Johnston, Steven; Gerber, Andreas; ...

2017-12-20

In this paper, CuIn xGa (1-x) (CIGS) mini-modules are stressed under reverse bias, resembling partial shading conditions, to predict and characterize where failures occur. Partial shading can cause permanent damage in the form of 'wormlike' defects on thin-film modules due to thermal runaway. This results in module-scale power losses. We have used dark lock-in thermography (DLIT) to spatially observe localized heating when reverse-bias breakdown occurs on various CIGS mini-modules. For better understanding of how and where these defects originated and propagated, we have developed techniques where the current is limited during reverse-bias stressing. This allows for DLIT-based detection and detailedmore » studying of the region where breakdown is initiated before thermal runaway leads to permanent damage. Statistics of breakdown sites using current-limited conditions has allowed for reasonable identification of the as-grown defects where permanent breakdown will likely originate. Scanning electron microscope results and wormlike defect analysis show that breakdown originates in defects such as small pits, craters, or cracks in the CIGS layer, and the wormlike defects propagate near the top CIGS interface.« less

Photovoltaic Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duty, C.; Angelini, J.; Armstrong, B.

The goal of the current project was to help make the US solar industry a world leader in the manufacture of thin film photovoltaics. The overall approach was to leverage ORNL’s unique characterization and processing technologies to gain a better understanding of the fundamental challenges for solar cell processing and apply that knowledge to targeted projects with industry members. ORNL has the capabilities in place and the expertise required to understand how basic material properties including defects, impurities, and grain boundaries affect the solar cell performance. ORNL also has unique processing capabilities to optimize the manufacturing process for fabrication ofmore » high efficiency and low cost solar cells. ORNL recently established the Center for Advanced Thin-film Systems (CATS), which contains a suite of optical and electrical characterization equipment specifically focused on solar cell research. Under this project, ORNL made these facilities available to industrial partners who were interested in pursuing collaborative research toward the improvement of their product or manufacturing process. Four specific projects were pursued with industrial partners: Global Solar Energy is a solar industry leader in full scale production manufacturing highly-efficient Copper Indium Gallium diSelenide (CIGS) thin film solar material, cells and products. ORNL worked with GSE to develop a scalable, non-vacuum, solution technique to deposit amorphous or nanocrystalline conducting barrier layers on untextured stainless steel substrates for fabricating high efficiency flexible CIGS PV. Ferro Corporation’s Electronic, Color and Glass Materials (“ECGM”) business unit is currently the world’s largest supplier of metallic contact materials in the crystalline solar cell marketplace. Ferro’s ECGM business unit has been the world's leading supplier of thick film metal pastes to the crystalline silicon PV industry for more than 30 years, and has had operational cells and modules in the field for 25 years. Under this project, Ferro leveraged world leading analytical capabilities at ORNL to characterize the paste-to-silicon interface microstructure and develop high efficiency next generation contact pastes. Ampulse Corporation is developing a revolutionary crystalline-silicon (c-Si) thin-film solar photovoltaic (PV) technology. Utilizing uniquely-textured substrates and buffer materials from the Oak Ridge National Laboratory (ORNL), and breakthroughs in Hot-Wire Chemical Vapor Deposition (HW-CVD) techniques in epitaxial silicon developed at the National Renewable Energy Laboratory (NREL), Ampulse is creating a solar technology that is tunable in silicon thickness, and hence in efficiency and economics, to meet the specific requirements of multiple solar PV applications. This project focused on the development of a high rate deposition process to deposit Si, Ge, and Si1-xGex films as an alternate to hot-wire CVD. Mossey Creek Solar is a start-up company with great expertise in the solar field. The primary interest is to create and preserve jobs in the solar sector by developing high-yield, low-cost, high-efficiency solar cells using MSC-patented and -proprietary technologies. The specific goal of this project was to produce large grain formation in thin, net-shape-thickness mc-Si wafers processed with high-purity silicon powder and ORNL's plasma arc lamp melting without introducing impurities that compromise absorption coefficient and carrier lifetime. As part of this project, ORNL also added specific pieces of equipment to enhance our ability to provide unique insight for the solar industry. These capabilities include a moisture barrier measurement system, a combined physical vapor deposition and sputtering system dedicated to cadmium-containing deposits, adeep level transient spectroscopy system useful for identifying defects, an integrating sphere photoluminescence system, and a high-speed ink jet printing system. These tools were combined with others to study the effect of defects on the performance of crystalline silicon and thin film solar cells, to explore non-vacuum ink-based approaches to solar cell production, as well as large-scale and low-cost deposition and processing of thin film CdTe material.« less

7 CFR 1466.27 - Conservation Innovation Grants (CIG).

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 10 2014-01-01 2014-01-01 false Conservation Innovation Grants (CIG). 1466.27 Section... PROGRAM Contracts and Payments § 1466.27 Conservation Innovation Grants (CIG). (a) Definitions. In... relationship is the transfer of a thing of value to a recipient in order to accomplish a public purpose of...

7 CFR 1466.27 - Conservation Innovation Grants (CIG).

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 10 2012-01-01 2012-01-01 false Conservation Innovation Grants (CIG). 1466.27 Section... PROGRAM Contracts and Payments § 1466.27 Conservation Innovation Grants (CIG). (a) Definitions. In... relationship is the transfer of a thing of value to a recipient in order to accomplish a public purpose of...

7 CFR 1466.27 - Conservation Innovation Grants (CIG).

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 10 2013-01-01 2013-01-01 false Conservation Innovation Grants (CIG). 1466.27 Section... PROGRAM Contracts and Payments § 1466.27 Conservation Innovation Grants (CIG). (a) Definitions. In... relationship is the transfer of a thing of value to a recipient in order to accomplish a public purpose of...

Optimization of low cost, non toxic, earth abundant p-type Cu2SnS3 thin film for Photovoltaic application

NASA Astrophysics Data System (ADS)

Chaudhari, J. J.; Patel, S.; Joshi, U. S.

2016-09-01

Cu2SnS3 (CTS) is one of promising candidate as an absorber material for thin film solar cell. Because of relatively higher prize of Indium and hazardous environmental impact of processing of Gallium, CTS is suitable alternative candidate to Cu2SnS3 (CIGS) based solar cell as its constituent elements such as copper, tin and sulphur are abundantly available in earth's crust. CTS is ternary semiconductor and its energy band gap is 1.5eV, which is perfectly matched with solar energy spectrum for maximum transfer of solar energy into electrical energy through photovoltaic action. The primary methods for the synthesis of CTS are Thermal evaporation, electrochemical, sputtering and wet chemical methods. Here in this paper we have optimized a low cost non-vacuum solution process method for the synthesis of CTS without any external sulfurization. The X-ray diffraction studies showed the formation of phase with the peaks corresponding to (112), (220) and (312) planes. Chemical Solution Deposition (CSD) for the synthesis of CTS is suitable for large area deposition and it includes several routes like solvothermal methods, direct liquid coating and nano ink based technique. The metal Chloride salts and thiourea is used as a source of sulphur to synthesize CTS solution and homogeneous thin films of CTS deposited on glass substrate using spin coating method. Use of abrasive solvent like hydrazine and hydrogen sulphide gas which are used to synthesize CTS thin film have detrimental effect on environment, we report eco friendly solvent based approach to synthesize CTS at low temperature 200 °C.

Successful Nicotine Intake in Medical Assisted Use of E-Cigarettes: A Pilot Study

PubMed Central

Pacifici, Roberta; Pichini, Simona; Graziano, Silvia; Pellegrini, Manuela; Massaro, Giuseppina; Beatrice, Fabio

2015-01-01

The electronic cigarette (e-cig) has gained popularity as an aid in smoking cessation programs mainly because it maintains the gestures and rituals of tobacco smoking. However, it has been shown in inexperienced e-cig users that ineffective nicotine delivery can cause tobacco craving that could be responsible for unsuccessful smoking reduction/cessation. Moreover, the incorrect use of an e-cig could also led to potential nicotine overdosage and intoxication. Medically assisted training on the proper use of an e-cig plus behavioral support for tobacco dependence could be a pivotal step in avoiding both issues. We performed an eight-month pilot study of adult smokers who started e-cig use after receiving a multi-component medically assisted training program with monitoring of nicotine intake as a biomarker of correct e-cig use. Participants were tested during follow-up for breath carbon monoxide (CO), plasma cotinine and trans-3’-hydroxycotinine, and number of tobacco cigarettes smoked. At the end of the first, fourth, and eighth month of follow-up, 91.1, 73.5, and 76.5% of participants respectively were e-cig users (‘only e-cig’ and ‘dual users’). They showed no significant variation in plasma cotinine and trans-3’-hydroxycotinine with respect to the start of the study when they smoked only tobacco cigarettes, but a significant reduction in breath CO. The proposed medically assisted training program of e-cig use led to a successful nicotine intake, lack of typical cigarette craving and overdosage symptoms and a significant decrease in the biomarker of cigarette combustion products. PMID:26184244

Effect of yoghurt or yoghurt serum on microbial quality of cig kofte.

PubMed

Dogan, Mahmut; Cankurt, Hasan; Toker, Omer Said; Yetim, Hasan; Sagdic, Osman

2014-07-01

Cig kofte, raw meatball is a traditionally produced meat product in Turkey and some other Middle East countries. It is prepared from mixtures of finely minced raw beef, bulgur, onions, various spices and tap water. Cig kofte is an uncooked product and popularly consumed with lettuce and lemon juice. In this study, yoghurt or yoghurt serum (YS) were added to the mixtures of cig kofte instead of tap water to reduce microbial risks of the raw meatball. Additionally, the effects of yoghurt and YS on some physicochemical characteristics of cig kofte were investigated. Cig kofte is generally consumed within a few hours after the preparation because of its raw nature. Also, it is generally sold under unhygienic conditions in restaurants and restaurant-like places. For this purpose, reducing of the microbial load of cig kofte is important. In the results, Escherichia coli and Listeria monocytogenes were not detected in any samples. While lactic acid bacteria count increased by addition of yoghurt and YS, the number of other microorganisms except for total aerobic mesophilic bacteria (TAMB) were decreased. The aw values and% moisture contents of the samples were varied between 0.88-0.94 and 46.25-49.72, respectively. The pH values of the samples were slightly changed during the storage of 24 h while no changes detected in the control samples during the storage. In conclusion, it can be suggested that using the yoghurt or YS instead of tap water in the preparation of cig kofte might ensure the microbial safety, increase the nutritional value and its flavour or aroma.

Surface Modification of Cu(In,Ga)Se2 Grains

NASA Astrophysics Data System (ADS)

Alruqobah, Essam H.

Nearly all of the world’s energy demand today is being met by the use of non-renewable energy sources. With the worldwide energy demand projected to increase in the coming years, it is vital to find alternative and renewable energy sources. Among the available renewable energy sources, solar energy is the most promising in meeting the worldwide energy demand. Recently, thin film solar cells have garnered attention due to their thinner architecture and relatively high optical absorption coefficients, as opposed to the conventional crytslline silicon solar cells. One of the most promising thin-film solar cell absorber materials is Cu(In,Ga)Se2 (CIGSe), achieving power conversion efficiencies approaching those of crystalline Si. The highest efficiency CIGSe devices were made via costly vacuum-based co-evaporation process. CIGSe devices made from solution-processed methods have also garnered attention due to their lower costs, and their efficiencies have increased considerably in recent years. In this thesis, CIGSe absorber layers are fabricated via the solution-processed from nanoparticle-based sulfide CIGS. The most important step in fabrication of a CIGSe solar cell absorber layer is the selenization step, which is the thermal sintering of a CIGSe precursor layer in the presence of selenium vapor to achieve large, dense selenide grains that are required for adequate PV performance. It is determined that maintaining adequate selenium vapor pressure on the substrate during the selenization and subsequent cooldown is crucial in producing high efficiency solar cell devices. Furthermore, exposing the CIGSe grains to a Se-deficient atmosphere causes Se to evaporate from the grains, and subsequently modifying the CIGSe grain surface. The modified grain surface adversely impacts the PV performance of the final solar cell device by forming defects due to the decrease in selenium concentration. These defects are manifested in increased current shunting, and decrease the overall efficiency of the device.

Analysis of the process of representing clinical statements for decision-support applications: a comparison of openEHR archetypes and HL7 virtual medical record.

PubMed

González-Ferrer, A; Peleg, M; Marcos, M; Maldonado, J A

2016-07-01

Delivering patient-specific decision-support based on computer-interpretable guidelines (CIGs) requires mapping CIG clinical statements (data items, clinical recommendations) into patients' data. This is most effectively done via intermediate data schemas, which enable querying the data according to the semantics of a shared standard intermediate schema. This study aims to evaluate the use of HL7 virtual medical record (vMR) and openEHR archetypes as intermediate schemas for capturing clinical statements from CIGs that are mappable to electronic health records (EHRs) containing patient data and patient-specific recommendations. Using qualitative research methods, we analyzed the encoding of ten representative clinical statements taken from two CIGs used in real decision-support systems into two health information models (openEHR archetypes and HL7 vMR instances) by four experienced informaticians. Discussion among the modelers about each case study example greatly increased our understanding of the capabilities of these standards, which we share in this educational paper. Differing in content and structure, the openEHR archetypes were found to contain a greater level of representational detail and structure while the vMR representations took fewer steps to complete. The use of openEHR in the encoding of CIG clinical statements could potentially facilitate applications other than decision-support, including intelligent data analysis and integration of additional properties of data items from existing EHRs. On the other hand, due to their smaller size and fewer details, the use of vMR potentially supports quicker mapping of EHR data into clinical statements.

A Review of Pulmonary Toxicity of Electronic Cigarettes in the Context of Smoking: A Focus on Inflammation.

PubMed

Shields, Peter G; Berman, Micah; Brasky, Theodore M; Freudenheim, Jo L; Mathe, Ewy; McElroy, Joseph P; Song, Min-Ae; Wewers, Mark D

2017-08-01

The use of electronic cigarettes (e-cigs) is increasing rapidly, but their effects on lung toxicity are largely unknown. Smoking is a well-established cause of lung cancer and respiratory disease, in part through inflammation. It is plausible that e-cig use might affect similar inflammatory pathways. E-cigs are used by some smokers as an aid for quitting or smoking reduction, and by never smokers (e.g., adolescents and young adults). The relative effects for impacting disease risk may differ for these groups. Cell culture and experimental animal data indicate that e-cigs have the potential for inducing inflammation, albeit much less than smoking. Human studies show that e-cig use in smokers is associated with substantial reductions in blood or urinary biomarkers of tobacco toxicants when completely switching and somewhat for dual use. However, the extent to which these biomarkers are surrogates for potential lung toxicity remains unclear. The FDA now has regulatory authority over e-cigs and can regulate product and e-liquid design features, such as nicotine content and delivery, voltage, e-liquid formulations, and flavors. All of these factors may impact pulmonary toxicity. This review summarizes current data on pulmonary inflammation related to both smoking and e-cig use, with a focus on human lung biomarkers. Cancer Epidemiol Biomarkers Prev; 26(8); 1175-91. ©2017 AACR . ©2017 American Association for Cancer Research.

Perceptions and Use of Electronic Cigarettes in Pregnancy

ERIC Educational Resources Information Center

McCubbin, Andrea; Fallin-Bennett, Amanda; Barnett, Janine; Ashford, Kristin

2017-01-01

Use of electronic cigarettes (e-cigs) is quickly growing in the United States, despite the unknown health implications and unregulated device contents. Although research is emerging around e-cigs in general, there continues to be a lack of scientific evidence regarding the safety and risks of e-cig use on maternal and fetal health, even though…

Special Analysis: Disposal of ETF Activated Carbon Vessels in Slit Trenches at the E-Area Low-Level Waste Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collard, L.B.

2003-08-25

This Special Analysis (SA) addresses two contaminants of concern, H-3 and I-129, in three Effluent Treatment Facility (ETF) Activated Carbon Vessels awaiting disposal as solid waste. The Unreviewed Disposal Question (UDQ) evaluation listed two options for disposal of this waste, disposal as Components-in-Grout (CIG) or disposal in Slit Trenches with sealed openings to restrict release of H-3 form the vessels. Consumption of the CIG inventory limit and consumption of CIG facility volume are shown for the ETF vessels to allow easy comparison with the consumption of Slit Trench inventory limit and consumption of the Slit Trench facility volume . Themore » inventory projections are based on doubling the inventory of the three ETF vessels in the E-Area to account for the unknown inventory of three ETF vessels in the ETF. When the grout ultimately is assumed to degrade hydraulically, the water movement is not impeded as much as the release is accelerated by the presence of the grout. Under these conditions for the CIG trenches relative to the Slit Trenches, the well concentrations are higher, the inventory limit is lower and for a given inventory the inventory limit consumption is higher.« less

Analysis of comments in a petition defending electronic cigarettes.

PubMed

Sumner, Holly Marie; McQueen, Amy; Scott, Michael John; Sumner, Walton

2014-11-01

A 2009 petition opposing a Food and Drug Administration (FDA) ban on electronic cigarettes (e-cigs) garnered international attention from e-cig users (vapers). Petitioners' comments described the perceived benefits of vaping. We conducted a qualitative and quantitative analysis of petitioners' comments. A sample of 200 petitioner names was sought in public records. Reviewers identified 13 major themes in a sample of comments, and themes related to current controversies were added. For each theme, software pattern-matching instructions (regular expressions) were developed and were used to scan comments. Agreement between reviewers and software was calculated; theme prevalence and clustering was ascertained. A total of 13,414 signatures and 8,285 comments from 50 states and 75 nations were collected in 6 months. Temporal patterns and name matches in public records suggest that most petitioners are authentic. Agreement between reviewers and software was moderate to high (κ = 0.4-0.8). Commonly cited themes were "e-cigs helped me quit" (34%), "a ban would be counterproductive" (15%), and "my health improved with e-cigs" (13%). Two clusters of themes emerged: the first combined comments about smoking cessation, health benefits, and smoking relapse that an e-cig ban would cause; the second combined themes that a "ban would be counterproductive," it would infringe on personal liberties, and it was motivated by government or industrial greed. People who cited mental health issues often mentioned avoiding withdrawal as a benefit of e-cigs. Early e-cig adopters were both frustrated and confused by discussion of a ban. They believed that e-cigs safely delivered nicotine and helped them quit smoking. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Electronic cigarette: a threat or an opportunity for public health? State of the art and future perspectives.

PubMed

Protano, C; Di Milia, L M; Orsi, G B; Vitali, M

2015-01-01

The e-cigarette, also known as e-cig, represents an emerging issue of great concern for public health. The aim of the present report was to explore the scientific literature about the use of electronic cigarette (e-cig), with a particular reference to the features of "toxicological safety", "effectiveness in overcoming the addiction to smoking the traditional cigarette" and "necessary research agenda". The efficacy of e-cig for smoking cessation is uncertain: some authors found that it can be a valid support, but long-term cessation rate has not be assessed. Other studies evidenced that e-cig is often used not for quitting smoking but to avoid smoking ban for traditional cigarettes and, even, some researches evidenced that it appears to contribute to nicotine addiction. E-cig smoking seems to be less dangerous of conventional cigarettes, but its use is not risk-free. Besides, cases of accidental or intentional poisoning with liquid solutions of e-cig have been reported. Also, the smoke of e-cig decreases indoor air quality, releasing particulate matter and other toxics that can persist on surfaces for days and generating passive exposure. These phenomena are similar to environmental tobacco smoke produced by conventional smoking, that is the sum of second- and third-hand smoke. We propose to call them "environmental electronic smoke", "electronic-second- hand smoke" and "electronic-third-hand smoke", respectively. Uncertainties relating to e-cig features determined the sequence, in the short term, of warnings and regulations approved and then replaced. In conclusion, although in recent years many researches were performed, evidences is limited and there is a need to study in deep all these issues.

Protective Effects of Cornel Iridoid Glycoside in Rats After Traumatic Brain Injury.

PubMed

Ma, Denglei; Wang, Na; Fan, Xiaotong; Zhang, Lan; Luo, Yi; Huang, Rui; Zhang, Li; Li, Yali; Zhao, Guoguang; Li, Lin

2018-04-01

Cornel iridoid glycoside (CIG) is the active ingredient extracted from Cornus officinalis. Our previous studies showed that CIG had protective effects on several brain injury models. In the present study, we aimed to examine the effects and elucidate the mechanisms of CIG against traumatic brain injury (TBI). TBI was induced in the right cerebral cortex of male adult rats. The neurological and cognitive functions were evaluated by modified neurological severity score (mNSS) and object recognition test (ORT), respectively. The level of serum S100β was measured by an ELISA method. Nissl staining was used to estimate the neuron survival in the brain. The expression of proteins was determined by western blot and/or immunohistochemical staining. We found that intragastric administration of CIG in TBI rats ameliorated the neurological defects and cognitive impairment, and alleviated the neuronal loss in the injured brain. In the acute stage of TBI (24-72 h), CIG decreased the level of S100β in the serum and brain, increased the ratio of Bcl-2/Bax and decreased the expression of caspase-3 in the injured cortex. Moreover, the treatment with CIG for 30 days increased the levels of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), enhanced the expression of synapsin I, synaptophysin and postsynaptic density protein 95 (PSD-95), and inhibited the apoptosis-regulating factors in the chronic stage of TBI. The present study demonstrated that CIG had neuroprotective effects against TBI through inhibiting apoptosis in the acute stage and promoting neurorestoration in the chronic stage. The results suggest that CIG may be beneficial to TBI therapy.

Selenization of CIS and CIGS layers deposited by chemical spray pyrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Babu, B. J.; Egaas, B.; Velumani, S.

Cu(In1-xGax)Se2 (CIGS) thin films with x=0 (CIS) and x=0.3 (CIGS) were prepared on Mo-coated glass substrate by using chemical spray pyrolysis at a substrate temperature of 350 degrees C, followed by selenization treatment at 550 degrees C in selenium environment under N2 gas flow. X-ray diffraction patterns of as-deposited CIGS layers on Mo showed polycrystalline chalcopyrite phase with an intense (112) plane. Splitting of (204)/(220) and (116)/(312) planes for the film with x=0.3 reveals deviation of tetragonal nature. Field emission scanning electron microscopy cross-sectional images of selenized films showed clear re-crystallization of grains. During the selenization process of the CIGSmore » absorber, a thin interface layer of MoSe2 is formed. Line mapping of Mo/CIGS layer showed more gallium segregation at the interface of back contact resulting in band gap grading. Chemical composition and mapping of the as-deposited and selenized samples were determined by energy dispersive analysis of X-rays. This work leads to fabrication of low cost and large scale Mo/CIGS/CdS/ZnO/ZnO:Al device structure.« less

Strategies to reduce the open-circuit voltage deficit in Cu2ZnSn(S,Se)4 thin film solar cells

NASA Astrophysics Data System (ADS)

Kim, Jekyung; Shin, Byungha

2017-09-01

Cu2ZnSn(S,Se)4 thin film solar cell has attracted significant attention in thin film solar cell technologies considering its low-cost, non-toxicity, and earth-abundance. However, the highest efficiency still remains at 12.6%, far below the theoretical efficiency of Shockley-Queisser (SQ) limit of around 30%. The limitation behind such shortcoming in the device performance was reported to stem primarily from a high V oc deficit compared to other thin film solar cell technologies such as CdTe or Cu(In,Ga)Se2 (CIGS), whose origins are attributed to the prevalence of band tailing from cation disordering as well as to the high recombination at the interfaces. In this report, systematic studies on the causes of a high V oc deficit and associated remarkable approaches to achieve high V oc have been reviewed, provided with a guidance on the future direction of CZTSSe research in resolving the high V oc deficit issue. [Figure not available: see fulltext.

Development of Electrodeposited CIGS Solar Cells: Cooperative Research and Development Final Report, CRADA Number CRD-09-357

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neale, Nathan

2016-09-01

At present, most PV materials are fabricated by vacuum technologies. Some of the many disadvantages of vacuum technology are complicated instrumentation, material waste, high cost of deposition per surface area, and instability of some compounds at the deposition temperature. Solution-based approaches for thin-film deposition on large areas are particularly desirable because of the low capital cost of the deposition equipment, relative simplicity of the processes, ease of doping, uniform deposition on a variety of substrates (including interior and exterior of tubes and various nonplanar devices), and potential compatibility with high-throughput (e.g., roll-to-roll) processing. Of the nonsilicon solar photovoltaic device modulesmore » that have been deployed to date, those based on the n-CdS/p-CdTe is a leading candidate. Two features in the optical characteristics of CdTe absorber are particularly attractive for photovoltaic conversion of sunlight; (a) its energy bandgap of 1.5 eV, which provides an optimal match with the solar spectrum and thus facilitates its efficient utilization and (b) the direct mode of the main optical transition which results in a large absorption coefficient and turn permits the use of thin layer (1-2 um) of active material. Thin films of CdTe required for these devices have been fabricated by a variety of methods (e.g., vapor transport deposition, vacuum deposition, screen printing and close-spaced sublimation). Electrodeposition is another candidate deserves more attention. This project will focus on delivering low-cost, high efficiency electrodeposited CdTe-based device.« less

Composition and emissions of VOCs in main- and side-stream smoke of research cigarettes

NASA Astrophysics Data System (ADS)

Charles, Simone M.; Batterman, S. A.; Jia, Chunrong

It is well known that mainstream (MS) and sidestream (SS) cigarette smoke contains a vast number of chemical substances. Previous studies have emphasized SS smoke rather than MS smoke to which smokers are exposed, and most have used chamber tests that have several disadvantages such as wall losses. Emissions from standard research cigarettes have been measured, but relatively few constituents have been reported, and only the 1R4F (low nicotine) cigarette type has been tested. This study provides a comprehensive characterization of total, MS and SS smoke emissions for the 1R5F (ultra low nicotine), 2R4F (low nicotine), and 1R3F (standard nicotine) research cigarettes research cigarettes, including emission factors for a number of toxic compounds (e.g., benzene) and tobacco smoke tracers (e.g., 2,5-dimethyl furan). Emissions of volatile organic compounds (VOCs) and particulate matter (PM) are quantified using a dynamic dilution emission measurement system that is shown to produce accurate, rapid and reproducible results for over 30 VOCs and PM. SS and MS emissions were accurately apportioned based on a mass balance of total emissions. As expected, SS emissions greatly exceeded MS emissions. The ultra low nicotine cigarette had lower emissions of most VOCs compared to low and standard nicotine cigarettes, which had similar emissions. Across the three types of cigarettes, emissions of benzene (296-535 μg cig -1), toluene (541-1003 μg cig -1), styrene (90-162 μg cig -1), 2-dimethyl furan (71-244 μg cig -1), naphthalene (15-18 μg cig -1) and other VOCs were generally comparable to or somewhat higher than literature estimates using chamber tests.

Full space device optimization for solar cells.

PubMed

Baloch, Ahmer A B; Aly, Shahzada P; Hossain, Mohammad I; El-Mellouhi, Fedwa; Tabet, Nouar; Alharbi, Fahhad H

2017-09-20

Advances in computational materials have paved a way to design efficient solar cells by identifying the optimal properties of the device layers. Conventionally, the device optimization has been governed by single or double descriptors for an individual layer; mostly the absorbing layer. However, the performance of the device depends collectively on all the properties of the material and the geometry of each layer in the cell. To address this issue of multi-property optimization and to avoid the paradigm of reoccurring materials in the solar cell field, a full space material-independent optimization approach is developed and presented in this paper. The method is employed to obtain an optimized material data set for maximum efficiency and for targeted functionality for each layer. To ensure the robustness of the method, two cases are studied; namely perovskite solar cells device optimization and cadmium-free CIGS solar cell. The implementation determines the desirable optoelectronic properties of transport mediums and contacts that can maximize the efficiency for both cases. The resulted data sets of material properties can be matched with those in materials databases or by further microscopic material design. Moreover, the presented multi-property optimization framework can be extended to design any solid-state device.

Developing Market Opportunities for Flexible Rooftop Applications of PV Using Flexible CIGS Technology: Market Considerations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabnani, L.; Skumanich, A.; Ryabova, E.

There has been a recent upsurge in developments for building-integrated phototovoltaics (BiPV) roof top materials based on CIGS. Several new companies have increased their presence and are looking to bring products to market for this application in 2011. For roof-top application, there are significant key requirements beyond just having good conversion efficiency. Other attributes include lightweight, as well as moisture-proof, and fully functionally reliable. The companies bringing these new BIPV/BAPV products need to ensure functionality with a rigorous series of tests, and have an extensive set of 'torture' tests to validate the capability. There is a convergence of form, aesthetics,more » and physics to ensure that the CIGS BiPV deliver on their promises. This article will cover the developments in this segment of the BiPV market and delve into the specific tests and measurements needed to characterize the products. The potential market sizes are evaluated and the technical considerations developed.« less

Methods of forming CIGS films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mansfield, Lorelle; Ramanathan, Kannan

2017-09-19

Methods for forming CIGS films are provided. According to an aspect of the invention, a method of forming a CIGS film includes a precursor step, which includes simultaneously evaporating Cu, In, Ga, Se, and Sb onto a substrate. The Se is incident on the substrate at a rate of at least 20 .ANG./s. The method also includes a selenization step, which includes evaporating Se over the substrate after the precursor step.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cho, Youngho; Hur, Kyeon; Kang, Yong

This study investigates the emerging harmonic stability concerns to be addressed by grid planners in generation interconnection studies, owing to the increased adoption of renewable energy resources connected to the grid via power electronic converters. The wideband and high-frequency electromagnetic transient (EMT) characteristics of these converter-interfaced generators (CIGs) and their interaction with the grid impedance are not accurately captured in the typical dynamic studies conducted by grid planners. This paper thus identifies the desired components to be studied and subsequently develops a practical process for integrating a new CIG into a grid with the existing CIGs. The steps of thismore » process are as follows: the impedance equation of a CIG using its control dynamics and an interface filter to the grid, for example, an LCL filter (inductor-capacitor-inductor type), is developed; an equivalent impedance model including the existing CIGs nearby and the grid observed from the point of common coupling are derived; the system stability for credible operating scenarios is assessed. Detailed EMT simulations validate the accuracy of the impedance models and stability assessment for various connection scenarios. Here, by complementing the conventional EMT simulation studies, the proposed analytical approach enables grid planners to identify critical design parameters for seamlessly integrating a new CIG and ensuring the reliability of the grid.« less

Effect of e-Cigarette Use on Cough Reflex Sensitivity.

PubMed

Dicpinigaitis, Peter V; Lee Chang, Alfredo; Dicpinigaitis, Alis J; Negassa, Abdissa

2016-01-01

E-cigarettes (e-cigs) have attained widespread popularity, yet knowledge of their physiologic effects remains minimal. The aim of this study was to evaluate the effect of a single exposure to e-cig vapor on cough reflex sensitivity. Thirty healthy nonsmokers underwent cough reflex sensitivity measurement using capsaicin cough challenge at baseline, 15 min, and 24 h after e-cig exposure (30 puffs 30 s apart). The end point of cough challenge is the concentration of capsaicin inducing five or more coughs (C5). The number of coughs induced by each e-cig inhalation was counted. A subgroup of subjects (n = 8) subsequently underwent an identical protocol with a non-nicotine-containing e-cig. Cough reflex sensitivity was significantly inhibited (C5 increased) 15 min after e-cig use (?0.29; 95% CI, ?0.43 to ?0.15; P < .0001); 24 h later, C5 returned to baseline (0.24; 95% CI, 0.10-0.38; P = .0002 vs post-15-min value). A subgroup of eight subjects demonstrating the largest degree of cough reflex inhibition had no suppression after exposure to a non-nicotine-containing e-cig (P = .0078 for comparison of ?C5 after nicotine vs non-nicotine device). Furthermore, more coughing was induced by the nicotine-containing vs non-nicotine-containing device (P = .0156). A single session of e-cig use, approximating nicotine exposure of one tobacco cigarette, induces significant inhibition of cough reflex sensitivity. Exploratory analysis of a subgroup of subjects suggests that nicotine is responsible for this observation. Our data, consistent with previous studies of nicotine effect, suggest a dual action of nicotine: an immediate, peripheral protussive effect and a delayed central antitussive effect. ClinicalTrials.gov; No.: NCT02203162; URL: www.clinicaltrials.gov. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Evaluating the economic viability of CdTe/CIS and CIGS/CIS tandem photovoltaic modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nanayakkara, Sanjini U.; Horowitz, Kelsey; Kanevce, Ana

In this paper, we analyze the potential cost competitiveness of two frameless, glass–glass thin-film tandem photovoltaic module structures, cadmium telluride (CdTe)/CuInSe 2 (CIS) and CuIn 0.3Ga 0.7Se 2 (CIGS)/CIS, based on the demonstrated cost of manufacturing the respective component cell technologies in high volume. To consider multiple economic scenarios, we base the CdTe/CIS module efficiency on the current industrial production of CdTe modules, while for CIGS/CIS, we use an aspirational estimate for CIGS efficiency. We focus on four-terminal mechanically stacked structures, thus avoiding the need to achieve current matching between the two cells. The top cell in such a tandemmore » must have a transparent back contact, which has not been successfully implemented to date. However, for the purpose of understanding the economic viability of both tandems, we assume that this can be implemented at a cost similar to that of sputtered indium tin oxide. The cost of both tandem module structures was found to be nearly identical on an equal-area basis and approximately $30/m 2 higher than the single-junction alternatives. Both tandem modules are about 4% (absolute) more efficient than a module by using the top-cell material alone. We find that these tandem modules might reduce total system cost by as much as 11% in applications having a high area-related balance-of-system cost, such as area-constrained residential systems; however, the relative advantage of tandems decreases in the cases where balance-of-system costs are lower, such as in commercial and utility scale systems.« less

Evaluating the economic viability of CdTe/CIS and CIGS/CIS tandem photovoltaic modules

DOE PAGES

Nanayakkara, Sanjini U.; Horowitz, Kelsey; Kanevce, Ana; ...

2017-01-20

In this paper, we analyze the potential cost competitiveness of two frameless, glass–glass thin-film tandem photovoltaic module structures, cadmium telluride (CdTe)/CuInSe 2 (CIS) and CuIn 0.3Ga 0.7Se 2 (CIGS)/CIS, based on the demonstrated cost of manufacturing the respective component cell technologies in high volume. To consider multiple economic scenarios, we base the CdTe/CIS module efficiency on the current industrial production of CdTe modules, while for CIGS/CIS, we use an aspirational estimate for CIGS efficiency. We focus on four-terminal mechanically stacked structures, thus avoiding the need to achieve current matching between the two cells. The top cell in such a tandemmore » must have a transparent back contact, which has not been successfully implemented to date. However, for the purpose of understanding the economic viability of both tandems, we assume that this can be implemented at a cost similar to that of sputtered indium tin oxide. The cost of both tandem module structures was found to be nearly identical on an equal-area basis and approximately $30/m 2 higher than the single-junction alternatives. Both tandem modules are about 4% (absolute) more efficient than a module by using the top-cell material alone. We find that these tandem modules might reduce total system cost by as much as 11% in applications having a high area-related balance-of-system cost, such as area-constrained residential systems; however, the relative advantage of tandems decreases in the cases where balance-of-system costs are lower, such as in commercial and utility scale systems.« less

Endothelial disruptive proinflammatory effects of nicotine and e-cigarette vapor exposures.

PubMed

Schweitzer, Kelly S; Chen, Steven X; Law, Sarah; Van Demark, Mary; Poirier, Christophe; Justice, Matthew J; Hubbard, Walter C; Kim, Elena S; Lai, Xianyin; Wang, Mu; Kranz, William D; Carroll, Clinton J; Ray, Bruce D; Bittman, Robert; Goodpaster, John; Petrache, Irina

2015-07-15

The increased use of inhaled nicotine via e-cigarettes has unknown risks to lung health. Having previously shown that cigarette smoke (CS) extract disrupts the lung microvasculature barrier function by endothelial cell activation and cytoskeletal rearrangement, we investigated the contribution of nicotine in CS or e-cigarettes (e-Cig) to lung endothelial injury. Primary lung microvascular endothelial cells were exposed to nicotine, e-Cig solution, or condensed e-Cig vapor (1-20 mM nicotine) or to nicotine-free CS extract or e-Cig solutions. Compared with nicotine-containing extract, nicotine free-CS extract (10-20%) caused significantly less endothelial permeability as measured with electric cell-substrate impedance sensing. Nicotine exposures triggered dose-dependent loss of endothelial barrier in cultured cell monolayers and rapidly increased lung inflammation and oxidative stress in mice. The endothelial barrier disruptive effects were associated with increased intracellular ceramides, p38 MAPK activation, and myosin light chain (MLC) phosphorylation, and was critically mediated by Rho-activated kinase via inhibition of MLC-phosphatase unit MYPT1. Although nicotine at sufficient concentrations to cause endothelial barrier loss did not trigger cell necrosis, it markedly inhibited cell proliferation. Augmentation of sphingosine-1-phosphate (S1P) signaling via S1P1 improved both endothelial cell proliferation and barrier function during nicotine exposures. Nicotine-independent effects of e-Cig solutions were noted, which may be attributable to acrolein, detected along with propylene glycol, glycerol, and nicotine by NMR, mass spectrometry, and gas chromatography, in both e-Cig solutions and vapor. These results suggest that soluble components of e-Cig, including nicotine, cause dose-dependent loss of lung endothelial barrier function, which is associated with oxidative stress and brisk inflammation.

E-cigarette aerosol exposure can cause craniofacial defects in Xenopus laevis embryos and mammalian neural crest cells

PubMed Central

Kennedy, Allyson E.; Kandalam, Suraj; Olivares-Navarrete, Rene

2017-01-01

Since electronic cigarette (ECIG) introduction to American markets in 2007, vaping has surged in popularity. Many, including women of reproductive age, also believe that ECIG use is safer than traditional tobacco cigarettes and is not hazardous when pregnant. However, there are few studies investigating the effects of ECIG exposure on the developing embryo and nothing is known about potential effects on craniofacial development. Therefore, we have tested the effects of several aerosolized e-cigarette liquids (e-cigAM) in an in vivo craniofacial model, Xenopus laevis, as well as a mammalian neural crest cell line. Results demonstrate that e-cigAM exposure during embryonic development induces a variety of defects, including median facial clefts and midface hypoplasia in two of e-cigAMs tested e-cigAMs. Detailed quantitative analyses of the facial morphology revealed that nicotine is not the main factor in inducing craniofacial defects, but can exacerbate the effects of the other e-liquid components. Additionally, while two different e-cigAMs can have very similar consequences on facial appearances, there are subtle differences that could be due to the differences in e-cigAM components. Further assessment of embryos exposed to these particular e-cigAMs revealed cranial cartilage and muscle defects and a reduction in the blood supply to the face. Finally, the expression of markers for vascular and cartilage differentiation was reduced in a mammalian neural crest cell line corroborating the in vivo effects. Our work is the first to show that ECIG use could pose a potential hazard to the developing embryo and cause craniofacial birth defects. This emphasizes the need for more testing and regulation of this new popular product. PMID:28957438

E-cigarette aerosol exposure can cause craniofacial defects in Xenopus laevis embryos and mammalian neural crest cells.

PubMed

Kennedy, Allyson E; Kandalam, Suraj; Olivares-Navarrete, Rene; Dickinson, Amanda J G

2017-01-01

Since electronic cigarette (ECIG) introduction to American markets in 2007, vaping has surged in popularity. Many, including women of reproductive age, also believe that ECIG use is safer than traditional tobacco cigarettes and is not hazardous when pregnant. However, there are few studies investigating the effects of ECIG exposure on the developing embryo and nothing is known about potential effects on craniofacial development. Therefore, we have tested the effects of several aerosolized e-cigarette liquids (e-cigAM) in an in vivo craniofacial model, Xenopus laevis, as well as a mammalian neural crest cell line. Results demonstrate that e-cigAM exposure during embryonic development induces a variety of defects, including median facial clefts and midface hypoplasia in two of e-cigAMs tested e-cigAMs. Detailed quantitative analyses of the facial morphology revealed that nicotine is not the main factor in inducing craniofacial defects, but can exacerbate the effects of the other e-liquid components. Additionally, while two different e-cigAMs can have very similar consequences on facial appearances, there are subtle differences that could be due to the differences in e-cigAM components. Further assessment of embryos exposed to these particular e-cigAMs revealed cranial cartilage and muscle defects and a reduction in the blood supply to the face. Finally, the expression of markers for vascular and cartilage differentiation was reduced in a mammalian neural crest cell line corroborating the in vivo effects. Our work is the first to show that ECIG use could pose a potential hazard to the developing embryo and cause craniofacial birth defects. This emphasizes the need for more testing and regulation of this new popular product.

Monitoring nicotine intake from e-cigarettes: measurement of parent drug and metabolites in oral fluid and plasma.

PubMed

Papaseit, Esther; Farré, Magí; Graziano, Silvia; Pacifici, Roberta; Pérez-Mañá, Clara; García-Algar, Oscar; Pichini, Simona

2017-03-01

Electronic cigarettes (e-cig) known as electronic nicotine devices recently gained popularity among smokers. Despite many studies investigating their safety and toxicity, few examined the delivery of e-cig-derived nicotine and its metabolites in alternative biological fluids. We performed a randomized, crossover, and controlled clinical trial in nine healthy smokers. Nicotine (NIC), cotinine (COT), and trans-3'-hydroxycotinine (3-HCOT) were measured in plasma and oral fluid by liquid chromatography-tandem mass spectrometry after consumption of two consecutive e-cig administrations or two consecutive tobacco cigarettes. NIC and its metabolites were detected both in oral fluid and plasma following both administration conditions. Concentrations in oral fluid resulted various orders of magnitude higher than those observed in plasma. Oral fluid concentration of tobacco cigarette and e-cig-derived NIC peaked at 15 min after each administration and ranged between 1.0 and 1396 μg/L and from 0.3 to 860 μg/L; those of COT between 52.8 and 110 μg/L and from 33.8 to 94.7 μg/L; and those of 3-HCOT between 12.4 and 23.5 μg/L and from 8.5 to 24.4 μg/L. The oral fluid to plasma concentration ratio of both e-cig- and tobacco cigarette-derived NIC peaked at 15 min after both administrations and correlated with oral fluid NIC concentration. The obtained results support the measurement of NIC and metabolites in oral fluid in the assessment of intake after e-cig use and appear to be a suitable alternative to plasma when monitoring nicotine delivery from e-cig for clinical and toxicological studies.

Method of junction formation for CIGS photovoltaic devices

DOEpatents

Delahoy, Alan E.

2006-03-28

Sulfur is used to improve the performance of CIGS devices prepared by the evaporation of a single source ZIS type compound to form a buffer layer on the CIGS. The sulfur may be evaporated, or contained in the ZIS type material, or both. Vacuum evaporation apparatus of many types useful in the practice of the invention are known in the art. Other methods of delivery, such as sputtering, or application of a thiourea solution, may be substituted for evaporation.

Method of junction formation for CIGS photovoltaic devices

DOEpatents

Delahoy, Alan E.

2010-01-26

Sulfur is used to improve the performance of CIGS devices prepared by the evaporation of a single source ZIS type compound to form a buffer layer on the CIGS. The sulfur may be evaporated, or contained in the ZIS type material, or both. Vacuum evaporation apparatus of many types useful in the practice of the invention are known in the art. Other methods of delivery, such as sputtering, or application of a thiourea solution, may be substituted for evaporation.

Bandgap Engineering of Cu(In 1-xGax)Se 2 Absorber Layers Fabricated using CuInSe 2 and CuGaSe 2 Targets for One-Step Sputtering Process

DOE PAGES

Park, Jae -Cheol; Lee, Jeon -Ryang; Al-Jassim, Mowafak; ...

2016-10-17

Here we have demonstrated that the bandgap of Cu(In 1-xGa x)Se 2(CIGS) absorber layers was readily controlled by using a one-step sputtering process. CIGS thin-film sample libraries with different Ga/(In + Ga) ratios were synthesized on soda-lime glass at 550 °C using a combinatorial magnetron sputtering system employing CuInSe 2(CIS) and CuGaSe 2(CGS) targets. Energy-dispersive X-ray fluorescence spectrometry (EDS-XRF) confirmed that the CIGS films had different Ga/(In + Ga) ratios, which were varied by the sample configuration on the substrate and ranged from 0.2 to 0.9. X-ray diffraction and Raman spectroscopy revealed that the CIGS films had a pure chalcopyritemore » phase without any secondary phase such as Cu-Se or ordered vacancy compound (OVC), respectively. Furthermore, we found that the optical bandgap energies of the CIGS films determined by transmittance measurements ranged from 1.07 eV to 1.53 eV as the Ga/(In + Ga) ratio increased from 0.2 to 0.9, demonstrating that the one-step sputtering process using CIS and CGS targets is another simple route to control the bandgap energy of the CIGS absorber layer.« less

E-cigarettes and flavorings induce inflammatory and pro-senescence responses in oral epithelial cells and periodontal fibroblasts.

PubMed

Sundar, Isaac K; Javed, Fawad; Romanos, Georgios E; Rahman, Irfan

2016-11-22

Electronic-cigarettes (e-cigs) represent a significant and increasing proportion of tobacco product consumption, which may pose an oral health concern. Oxidative/carbonyl stress via protein carbonylation is an important factor in causing inflammation and DNA damage. This results in stress-induced premature senescence (a state of irreversible growth arrest which re-enforces chronic inflammation) in gingival epithelium, which may contribute to the pathogenesis of oral diseases. We show that e-cigs with flavorings cause increased oxidative/carbonyl stress and inflammatory cytokine release in human periodontal ligament fibroblasts, Human Gingival Epithelium Progenitors pooled (HGEPp), and epigingival 3D epithelium. We further show increased levels of prostaglandin-E2 and cycloxygenase-2 are associated with upregulation of the receptor for advanced glycation end products (RAGE) by e-cig exposure-mediated carbonyl stress in gingival epithelium/tissue. Further, e-cigs cause increased oxidative/carbonyl and inflammatory responses, and DNA damage along with histone deacetylase 2 (HDAC2) reduction via RAGE-dependent mechanisms in gingival epithelium. A greater response is elicited by flavored e-cigs. Increased oxidative stress, pro-inflammatory and pro-senescence responses (DNA damage and HDAC2 reduction) can result in dysregulated repair due to proinflammatory and pro-senescence responses in periodontal cells. These data highlight the pathologic role of e-cig aerosol and its flavoring to cells and tissues of the oral cavity in compromised oral health.

Comparative In Vitro Toxicity Profile of Electronic and Tobacco Cigarettes, Smokeless Tobacco and Nicotine Replacement Therapy Products: E-Liquids, Extracts and Collected Aerosols

PubMed Central

Misra, Manoj; Leverette, Robert D.; Cooper, Bethany T.; Bennett, Melanee B.; Brown, Steven E.

2014-01-01

The use of electronic cigarettes (e-cigs) continues to increase worldwide in parallel with accumulating information on their potential toxicity and safety. In this study, an in vitro battery of established assays was used to examine the cytotoxicity, mutagenicity, genotoxicity and inflammatory responses of certain commercial e-cigs and compared to tobacco burning cigarettes, smokeless tobacco (SLT) products and a nicotine replacement therapy (NRT) product. The toxicity evaluation was performed on e-liquids and pad-collected aerosols of e-cigs, pad-collected smoke condensates of tobacco cigarettes and extracts of SLT and NRT products. In all assays, exposures with e-cig liquids and collected aerosols, at the doses tested, showed no significant activity when compared to tobacco burning cigarettes. Results for the e-cigs, with and without nicotine in two evaluated flavor variants, were very similar in all assays, indicating that the presence of nicotine and flavors, at the levels tested, did not induce any cytotoxic, genotoxic or inflammatory effects. The present findings indicate that neither the e-cig liquids and collected aerosols, nor the extracts of the SLT and NRT products produce any meaningful toxic effects in four widely-applied in vitro test systems, in which the conventional cigarette smoke preparations, at comparable exposures, are markedly cytotoxic and genotoxic. PMID:25361047

Cyclin B Proteolysis and the Cyclin-dependent Kinase Inhibitor rum1p Are Required for Pheromone-induced G1 Arrest in Fission Yeast

PubMed Central

Stern, Bodo; Nurse, Paul

1998-01-01

The blocking of G1 progression by fission yeast pheromones requires inhibition of the cyclin-dependent kinase cdc2p associated with the B-cyclins cdc13p and cig2p. We show that cyclosome-mediated degradation of cdc13p and cig2p is necessary for down-regulation of B-cyclin–associated cdc2p kinase activity and for phermone-induced G1 arrest. The cyclin-dependent kinase inhibitor rum1p is also required to maintain this G1 arrest; it binds both cdc13p and cig2p and is specifically required for cdc13p proteolysis. We propose that rum1p acts as an adaptor targeting cdc13p for degradation by the cyclosome. In contrast, the cig2p–cdc2p kinase can be down-regulated, and the cyclin cig2p can be proteolyzed independently of rum1p. We suggest that pheromone signaling inhibits the cig2p–cdc2p kinase, bringing about a transient G1 arrest. As a consequence, rum1p levels increase, thus inhibiting and inducing proteolysis of the cdc13p–cdc2p kinase; this is necessary to maintain G1 arrest. We have also shown that pheromone-induced transcription occurs only in G1 and is independent of rum1p. PMID:9614176

Passivation effect of Cl, F and H atoms on CuIn0.75Ga0.25Se2 (1 1 2) surface

NASA Astrophysics Data System (ADS)

Qi, Rong-fei; Wang, Zhao-hui; Tang, Fu-ling; Agbonkina, Itohan C.; Xue, Hong-tao; Si, Feng-juan; Ma, Sheng-ling; Wang, Xiao-ka

2018-06-01

Using the first-principles calculations within the density functional-theory (DFT) framework, we theoretically investigated the surface reconstruction, surface states near the Fermi level and their passivation on CuIn0.75Ga0.25Se2 (1 1 2) (CIGS) surface by chlorine, fluorine and hydrogen. Surface reconstruction appears on CIG-terminated CIGS (1 1 2) surface and it is a self-passivation. For the locations of Cl, F and H atoms adsorbing on Se-terminated CIGS (1 1 2) surface, four high symmetry adsorption sites: top sites, bridge sites, hexagonal close-packed (hcp) sites and faced centered cubic (fcc) sites were studied respectively. With the coverage of 0.5 monolayer (ML), Cl, F and H adatoms energetically occupy the top sites on the CIGS (112) surface. The corresponding adsorption energies were -2.20 eV, -3.29 eV, -2.60 eV, respectively. The bond length and electronic properties were analyzed. We found that the surface state density near the Fermi level was markedly diminished for 0.5 ML Cl, F and H adsorption on Se-terminated CIGS (1 1 2) surface at top sites. It was also found that H can more efficiently passivate the surface state density than Cl and F atoms, and the effect of adsorption of Cl atoms is better than that of F.

Daily users compared to less frequent users find vape as or more satisfying and less dangerous than cigarettes, and are likelier to use non-cig-alike vaping products.

PubMed

Kozlowski, Lynn T; Homish, D Lynn; Homish, Gregory G

2017-06-01

We assessed the roles of perceived satisfaction and perceived danger and vaping-product-type as correlates of more frequent use of vaping products. In a baseline assessment of a longitudinal study of US Army Reserve/National Guard Soldiers and their partners (New York State, USA, 2014-2016), participants were asked about current use of vaping products (e-cigarettes) and perceived satisfaction and danger in comparison to cigarettes as well as type of product used. Fisher-exact tests and multiple ordinal logistic regressions were used. In multivariable and univariate models, more perceived satisfaction, less perceived danger, and use of non-cig-alike products were associated with more frequent use of vaping products ( p s < 0.05, two-tailed). For self-selected, more frequent adult users, e-cigs can be at least as satisfying as cigarettes and often more satisfying and are perceived as less dangerous than cigarettes. Non-cig-alike products were more likely in daily users. Some concern that e-cigs are a gateway to cigarettes arises from assuming that e-cigs may not be as reinforcing and pleasurable as cigarettes. These results indicate that accurate perception of comparative risk and use of more effective-nicotine delivery product can produce for some users a highly-satisfying alternative to cigarettes.

E-Cigs, Menthol & Dip

MedlinePlus

... Close Search × MENU BACK CLOSE SMOKEFREE.GOV HOME E-Cigs, Menthol & Dip There are many types of tobacco products. Learn how e-cigarettes, menthol cigarettes, smokeless tobacco, and other products ...

Controlling morphology and crystallite size of Cu(In{sub 0.7}Ga{sub 0.3})Se{sub 2} nano-crystals synthesized using a heating-up method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, Wei-Hsiang; Hsiang, Hsing-I, E-mail: hsingi@mail.ncku.edu.tw; Chia, Chih-Ta

2013-12-15

CuIn{sub 0.7}Ga{sub 0.3}Se{sub 2}(CIGS) nano-crystals were successfully synthesized via a heating-up process. The non-coordinating solvent (1-octadecene) and selenium/cations ratio effects on the crystalline phase and crystallite size of CIGS nano-crystallites were investigated. It was observed that the CIGS nano-crystallite morphology changed from sheet into spherical shape as the amount of 1-octadecene addition was increased. CIGS nano-crystals were obtained in 9–20 nm sizes as the selenium/cations ratio increased. These results suggest that the monomer reactivity in the solution can be adjusted by changing the solvent type and selenium/cations ratio, hence affecting the crystallite size and distribution. - Graphical abstract: CuIn{sub 0.7}Ga{submore » 0.3}Se{sub 2}(CIGS) nano-crystals were successfully synthesized via a heating-up process in this study. The super-saturation in the solution can be adjusted by changing the OLA/ODE ratio and selenium/cation ratio.« less

The Pacific Northwest's Climate Impacts Group: Climate Science in the Public Interest

NASA Astrophysics Data System (ADS)

Mantua, N.; Snover, A.

2006-12-01

Since its inception in 1995, the University of Washington's Climate Impacts Group (CIG) (funded under NOAA's Regional Integrated Science and Assessments (RISA) Program) has become the leader in exploring the impacts of climate variability and climate change on natural and human systems in the U.S. Pacific Northwest (PNW), specifically climate impacts on water, forest, fish and coastal resource systems. The CIG's research provides PNW planners, decision makers, resource managers, local media, and the general public with valuable knowledge of ways in which the region's key natural resources are vulnerable to changes in climate, and how this vulnerability can be reduced. The CIG engages in climate science in the public interest, conducting original research on the causes and consequences of climate variability and change for the PNW and developing forecasts and decision support tools to support the use of this information in federal, state, local, tribal, and private sector resource management decisions. The CIG's focus on the intersection of climate science and public policy has placed the CIG nationally at the forefront of regional climate impacts assessment and integrated analysis.

Vapour phase techniques for deposition of CZTS thin films: A review

NASA Astrophysics Data System (ADS)

Kaur, Ramanpreet; Kumar, Sandeep; Singh, Sukhpal

2018-05-01

With the surge of thin film photovoltaic technologies in recent years, for cost reduction and increased production there is a need for earth abundant and non-toxic raw materials. Existing thin film solar cells comprising CuInS2 (CIS), CuInGaSe2 (CIGS) and CdTe contain elements that are rare in earth's crust and in case of CdTe toxic. Cu2ZnSnS4 (CZTS), having Kesterite structure, a direct band gap of 1.4 - 1.5 eV and an absorption coefficient of 104 cm-1 makes a promising candidate for absorber layer in thin film solar cells. So far many physical and chemical techniques have been employed for deposition of CZTS thin films. This review focuses on various vapour phase techniques used for fabrication of films, recent advances in these techniques and their future outlook.

Defect States in Copper Indium Gallium Selenide Solar Cells from Two-Wavelength Excitation Photoluminescence Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jensen, Soren A.; Dippo, Patricia; Mansfield, Lorelle M.

2016-11-21

We use two-wavelength excitation photoluminescence spectroscopy to probe defect states in CIGS thin films. Above-Eg excitation is combined with a tunable IR bias light that modulates the population of the defect states. We find that IR illumination in the range of 1400-2000 nm (0.62-0.89 eV) causes a reduction of the PL intensity, the magnitude of which scales linearly with IR power. Further, KF post deposition treatment has only a modest influence on the effect of the IR excitation. Initial data suggest that we have developed an optical characterization tool for band-gap defect states.

Scaling up Planetary Dynamo Modeling to Massively Parallel Computing Systems: The Rayleigh Code at ALCF

NASA Astrophysics Data System (ADS)

Featherstone, N. A.; Aurnou, J. M.; Yadav, R. K.; Heimpel, M. H.; Soderlund, K. M.; Matsui, H.; Stanley, S.; Brown, B. P.; Glatzmaier, G.; Olson, P.; Buffett, B. A.; Hwang, L.; Kellogg, L. H.

2017-12-01

In the past three years, CIG's Dynamo Working Group has successfully ported the Rayleigh Code to the Argonne Leadership Computer Facility's Mira BG/Q device. In this poster, we present some our first results, showing simulations of 1) convection in the solar convection zone; 2) dynamo action in Earth's core and 3) convection in the jovian deep atmosphere. These simulations have made efficient use of 131 thousand cores, 131 thousand cores and 232 thousand cores, respectively, on Mira. In addition to our novel results, the joys and logistical challenges of carrying out such large runs will also be discussed.

High-throughput combinatorial chemical bath deposition: The case of doping Cu (In, Ga) Se film with antimony

NASA Astrophysics Data System (ADS)

Yan, Zongkai; Zhang, Xiaokun; Li, Guang; Cui, Yuxing; Jiang, Zhaolian; Liu, Wen; Peng, Zhi; Xiang, Yong

2018-01-01

The conventional methods for designing and preparing thin film based on wet process remain a challenge due to disadvantages such as time-consuming and ineffective, which hinders the development of novel materials. Herein, we present a high-throughput combinatorial technique for continuous thin film preparation relied on chemical bath deposition (CBD). The method is ideally used to prepare high-throughput combinatorial material library with low decomposition temperatures and high water- or oxygen-sensitivity at relatively high-temperature. To check this system, a Cu(In, Ga)Se (CIGS) thin films library doped with 0-19.04 at.% of antimony (Sb) was taken as an example to evaluate the regulation of varying Sb doping concentration on the grain growth, structure, morphology and electrical properties of CIGS thin film systemically. Combined with the Energy Dispersive Spectrometer (EDS), X-ray Photoelectron Spectroscopy (XPS), automated X-ray Diffraction (XRD) for rapid screening and Localized Electrochemical Impedance Spectroscopy (LEIS), it was confirmed that this combinatorial high-throughput system could be used to identify the composition with the optimal grain orientation growth, microstructure and electrical properties systematically, through accurately monitoring the doping content and material composition. According to the characterization results, a Sb2Se3 quasi-liquid phase promoted CIGS film-growth model has been put forward. In addition to CIGS thin film reported here, the combinatorial CBD also could be applied to the high-throughput screening of other sulfide thin film material systems.

Regulation in the face of uncertainty: the evidence on electronic nicotine delivery systems (e-cigarettes).

PubMed

Farsalinos, Konstantinos E; Le Houezec, Jacques

2015-01-01

Tobacco smoking is the largest single preventable cause of many chronic diseases and death. Effective treatments exist; however, few smokers use them and most try to quit by themselves. Most of the tobacco cigarette's toxicity is related to the combustion process. Models of harm reduction applied to tobacco suggest that switching from inhalation of combustible products to a noncombustible nicotine delivery product would likely result in a vast reduction in tobacco-related death and illness. Currently available evidence raises no doubt that electronic cigarettes (e-cigs) are by far less harmful than smoking (although probably not absolutely safe) and have the potential to be the most effective tobacco harm reduction products due to their unique property of resembling smoking and providing satisfaction to the user. A lot of controversy is surrounding e-cigs and their regulation, much of which is based on the precautionary principle. Although monitoring and further research is definitely needed, the arguments used to implement severe restrictions or bans are mostly hypothetical, weakly supported by evidence, and, in some cases, derived from mispresentation or misinterpretation of the study findings. Regulators should keep in mind that the target population is smokers who want to reduce or quit their deadly tobacco consumption. To achieve this goal, smokers should be honestly informed on the relative harmfulness of the different products. E-cigs are not tobacco products and are not used as medications. For this reason, a specific regulatory scheme is needed, separate from tobacco or medicinal products regulation. Regulation should implement specific quality criteria for products, rules for the exclusion of chemicals of reasonable concern, and appropriate testing for possible contaminants. Additionally, manufacturing standards derived from the food industry should be implemented and adjusted for specific conditions related to e-cigs. Finding the appropriate balance between safety and acceptability of use by smokers will be important in achieving the maximum public health benefit. Labeling should be specified, with warnings about exposure to skin or through ingestion and discouragement of use by nonsmokers, related to the presence of nicotine. Finally, advertising and marketing should not be banned, but appropriately regulated in order to encourage use by the intended population while avoiding use by never-smokers. E-cigs should be appealing to smokers (but not to nonsmokers), while availability and pricing should be strong competitive advantages of e-cigs relative to tobacco cigarettes.

Cu(In,Ga)Se2 thin films annealed using a continuous wave Nd:YAG laser (λ0 = 532 nm): Effects of laser-annealing time

NASA Astrophysics Data System (ADS)

Yoo, Myoung Han; Ko, Pil Ju; Kim, Nam-Hoon; Lee, Hyun-Yong

2017-12-01

Preparation of Cu(In,Ga)Se2 (CIGS) thin films has continued to face problems related to the selenization of sputtered Cu-In-Ga precursors when using H2Se vapor in that the materials are highly toxic and the facilities extremely costly. Another obstacle facing the production of CIGS thin films has been the required annealing temperature, as it relates to the decomposition temperature of a typical flexible polymer substrate. A novel laser-annealing process for CIGS thin films, which does not involve the selenization process and which can be performed at a lower temperature, has been proposed. Following sputtering with a Cu0.9In0.7Ga0.3Se2 target, the laser-annealing of the CIGS thin film was performed using a continuous 532-nm Nd:YAG laser with an annealing time of 200 - 1000 s at a laser optical power of 2.75 W. CIGS chalcopyrite (112), (220/204), and (312/116) phases, with some weak diffraction peaks corresponding to the Cu-Se- or the In-Se-related phases, were successfully obtained for all the CIGS thin films that had been laser-annealed at 2.75 W. The lattice parameters, the d-spacing, the tetragonal distortion parameter, and the strain led to the crystallinity being worse and grain size being smaller at 600 s while better crystallinity was obtained at 200 and 800 s, which was closely related to the deviations from molecularity and stoichiometry, which were greatest at 600 s while the values exhibited near-stoichiometric compositions at 200 and 800 s. The band gaps of the laser-annealed CIGS thin films were within a range of 1.765 - 1.977 eV and depended on the internal stress. The mean absorbance of the laser-annealed CIGS thin films was within a range of 1.598 - 1.900, suggesting that approximately 97.47 - 98.74% of the incident photons in the visible spectral region were absorbed by this 400-nm film. The conductivity types exhibited the same deviations (Δ m > 0 and Δ s < 0) in all the laser-annealed CIGS thin films. After laser-annealing, the resistivity fell abruptly to a range of 3.551 × 10 -2 - 1.022 × 10 -1 Ω·cm. The carrier concentration was on the order of 1019 - 1021 cm -3, and the carrier mobility was 5.7 × 10 -2 - 5.7 × 100 cm2/V·s.

Raster Scan Computer Image Generation (CIG) System Based On Refresh Memory

NASA Astrophysics Data System (ADS)

Dichter, W.; Doris, K.; Conkling, C.

1982-06-01

A full color, Computer Image Generation (CIG) raster visual system has been developed which provides a high level of training sophistication by utilizing advanced semiconductor technology and innovative hardware and firmware techniques. Double buffered refresh memory and efficient algorithms eliminate the problem of conventional raster line ordering by allowing the generated image to be stored in a random fashion. Modular design techniques and simplified architecture provide significant advantages in reduced system cost, standardization of parts, and high reliability. The major system components are a general purpose computer to perform interfacing and data base functions; a geometric processor to define the instantaneous scene image; a display generator to convert the image to a video signal; an illumination control unit which provides final image processing; and a CRT monitor for display of the completed image. Additional optional enhancements include texture generators, increased edge and occultation capability, curved surface shading, and data base extensions.

Lorelle Mansfield, Ph.D. | NREL

Science.gov Websites

)Se2 (CIGS) thin films for photovoltaic applications. In particular, she is developing rapid two-step content, and band gap grading. While at NREL, she has also deposited CIGS on novel substrates using low

ECigs

Cancer.gov

You may have heard people talking about using electronic cigarettes (also called e-cigarettes or e-cigs) as a way to try to quit smoking. If you’re thinking about using an e-cig, here are three things you should know.

Surface and Bulk Effects of K in Highly Efficient Cu1-xKxInSe2 Solar Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muzzillo, Christopher; Mansfield, Lorelle M; Ramanathan, Kannan

To advance knowledge of the beneficial effects of K in Cu(In,Ga)(Se,S)2 (CIGS) photovoltaic (PV) absorbers, recent Cu-K-In-Se phase growth studies have been extended to PV performance. First, the effect of distributing K throughout bulk Cu1-xKxInSe2 absorbers at low K/(K+Cu) compositions (0 = x = 0.30) was studied. Efficiency, open-circuit voltage (VOC), and fill factor (FF) were greatly enhanced for x ~ 0.07, resulting in an officially-measured 15.0%-efficient solar cell, matching the world record CuInSe2 efficiency. The improvements were a result of reduced interface and bulk recombination, relative to CuInSe2 (x ~ 0). However, higher x compositions had reduced efficiency, short-circuitmore » current density (JSC), and FF due to greatly increased interface recombination, relative to the x ~ 0 baseline. Next, the effect of confining K at the absorber/buffer interface at high K/(K+Cu) compositions (0.30 = x = 0.92) was researched. Previous work showed that these surface layer growth conditions produced CuInSe2 with a large phase fraction of KInSe2. After optimization (75 nm surface layer with x ~ 0.41), these KInSe2 surface samples exhibited increased efficiency (officially 14.9%), VOC, and FF as a result of decreased interface recombination. The KInSe2 surfaces had features similar to previous reports for KF post-deposition treatments (PDTs) used in world record CIGS solar cells - taken as indirect evidence that KInSe2 can form during these PDTs. Both the bulk and surface growth processes greatly reduced interface recombination. However, the KInSe2 surface had higher K levels near the surface, greater lifetimes, and increased inversion near the buffer interface, relative to the champion bulk Cu1-xKxInSe2 absorber. These characteristics demonstrate that K may benefit PV performance by different mechanisms at the surface and in the absorber bulk.« less

Communication enabled – fast acting imbalance reserve (CE-FAIR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilches-Bernal, Felipe; Concepcion, Ricky; Neely, Jason C.

This letter presents a new frequency control strategy that takes advantage of communications and fast responding resources like PV generation, energy storage, wind generation, and demand response, termed collectively as converter interfaced generators (CIGs). The proposed approach uses an active monitoring of power imbalances to rapidly redispatch CIGs. This approach differs from previously proposed frequency control schemes in that it employs feed-forward control based on a measured power imbalance rather that relying on a frequency measurement. As a result, time-domain simulations of the full Western Electricity Coordinating Council (WECC) system are conducted to demonstrate the effectiveness of the proposed method,more » showing improved performance.« less

Communication enabled – fast acting imbalance reserve (CE-FAIR)

DOE PAGES

Wilches-Bernal, Felipe; Concepcion, Ricky; Neely, Jason C.; ...

2017-06-08

This letter presents a new frequency control strategy that takes advantage of communications and fast responding resources like PV generation, energy storage, wind generation, and demand response, termed collectively as converter interfaced generators (CIGs). The proposed approach uses an active monitoring of power imbalances to rapidly redispatch CIGs. This approach differs from previously proposed frequency control schemes in that it employs feed-forward control based on a measured power imbalance rather that relying on a frequency measurement. As a result, time-domain simulations of the full Western Electricity Coordinating Council (WECC) system are conducted to demonstrate the effectiveness of the proposed method,more » showing improved performance.« less

Different physiological and behavioural effects of e-cigarette vapour and cigarette smoke in mice.

PubMed

Ponzoni, L; Moretti, M; Sala, M; Fasoli, F; Mucchietto, V; Lucini, V; Cannazza, G; Gallesi, G; Castellana, C N; Clementi, F; Zoli, M; Gotti, C; Braida, D

2015-10-01

Nicotine is the primary addictive substance in tobacco smoke and electronic cigarette (e-cig) vapour. Methodological limitations have made it difficult to compare the role of the nicotine and non-nicotine constituents of tobacco smoke. The aim of this study was to compare the effects of traditional cigarette smoke and e-cig vapour containing the same amount of nicotine in male BALB/c mice exposed to the smoke of 21 cigarettes or e-cig vapour containing 16.8 mg of nicotine delivered by means of a mechanical ventilator for three 30-min sessions/day for seven weeks. One hour after the last session, half of the animals were sacrificed for neurochemical analysis, and the others underwent mecamylamine-precipitated or spontaneous withdrawal for the purposes of behavioural analysis. Chronic intermittent non-contingent, second-hand exposure to cigarette smoke or e-cig vapour led to similar brain cotinine and nicotine levels, similar urine cotinine levels and the similar up-regulation of α4β2 nicotinic acetylcholine receptors in different brain areas, but had different effects on body weight, food intake, and the signs of mecamylamine-precipitated and spontaneous withdrawal episodic memory and emotional responses. The findings of this study demonstrate for the first time that e-cig vapour induces addiction-related neurochemical, physiological and behavioural alterations. The fact that inhaled cigarette smoke and e-cig vapour have partially different dependence-related effects indicates that compounds other than nicotine contribute to tobacco dependence. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

7 CFR 1466.27 - Conservation Innovation Grants (CIG).

Code of Federal Regulations, 2011 CFR

2011-01-01

... lead to the transfer of conservation technologies, management systems, and innovative approaches (such... to stimulate the development and adoption of innovative conservation approaches and technologies... focus. Applications for CIG should demonstrate the use of innovative approaches and technologies to...

Investigation of Sb-Containing Precursors for Cu(In, Ga)Se2 Thin Films Through Design of Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mansfield, Lorelle M.; To, Bobby; Reedy, Robert C.

2016-11-21

The Design of Experiments (DoE) module in JMP statistical software was used to determine the best parameters for Sb-containing CIGS precursors with a fixed selenization step. Solar cells were fabricated and measured for all completed films. The most important factor influencing the current-voltage device parameters was identified as the temperature and antimony flux interaction. The DoE prediction profiler and predictive contour plots provided guidance to further improve the device parameters. In one follow-up run, we increased device efficiency from 14.9% to 15.5% Additional gains in efficiency to 16.9% were realized by introducing an intentional Ga gradient and an antireflective coating.

Sputtered Metal Oxide Broken Gap Junctions for Tandem Solar Cells

NASA Astrophysics Data System (ADS)

Johnson, Forrest

Broken gap metal oxide junctions have been created for the first time by sputtering using ZnSnO3 for the n-type material and Cu 2O or CuAlO2 for the p-type material. Films were sputtered from either ceramic or metallic targets at room temperature from 10nm to 220nm thick. The band structure of the respective materials have theoretical work functions which line up with the band structure for tandem CIAGS/CIGS solar cell applications. Multiple characterization methods demonstrated consistent ohmic I-V profiles for devices on rough surfaces such as ITO/glass and a CIAGS cell. Devices with total junction specific contact resistance of under 0.001 Ohm-cm2 have been achieved with optical transmission close to 100% using 10nm films. Devices showed excellent stability up to 600°C anneals over 1hr using ZnSnO3 and CuAlO2. These films were also amorphous -a great diffusion barrier during top cell growth at high temperatures. Rapid Thermal Anneal (RTA) demonstrated the ability to shift the band structure of the whole device, allowing for tuning it to align with adjacent solar layers. These results remove a key barrier for mass production of multi-junction thin film solar cells.

Applications of AMPS-1D for solar cell simulation

NASA Astrophysics Data System (ADS)

Zhu, Hong; Kalkan, Ali Kaan; Hou, Jingya; Fonash, Stephen J.

1999-03-01

The AMPS-1D PC computer program is now used by over 70 groups world-wide for detector and solar cell analysis. It has proved to be a very powerful tool in understanding device operation and physics for single crystal, poly-crystalline and amorphous structures. For example, AMPS-1D has been successful in explaining the "red kink" [1] and the "transient effect" in CdS/CIGS poly-crystalline solar cells. It has been used to show that thin film poly-Si structures, with reasonable light trapping, are capable of competitive solar cell conversion efficiencies. In the case of a-Si:H structures, it has been used, for example, to settle the discrepancies in bandgap measurement, to predict the effective QE>1 phenomenon later seen in these materials [2], to determine the relative roles of interface and bulk properties, and to point the direction toward 16% triple junction structures. In general AMPS-1D is used for cell and detector design, material parameter sensitivity studies, and parameter extraction. Recently we have shown that it can be used to determine optimum structure and light and voltage biasing conditions in the material parameter extraction function. Information on AMPS can be found at www.psu.edu/dept/AMPS/amps_web/AMPS.html and at other web sites set up by user groups.

Surface microstructure evolution of highly transparent and conductive Al-doped ZnO thin films and its application in CIGS solar cells

NASA Astrophysics Data System (ADS)

Cheng, Ke; Liu, Jingjing; Jin, Ranran; Liu, Jingling; Liu, Xinsheng; Lu, Zhangbo; Liu, Ya; Liu, Xiaolan; Du, Zuliang

2017-07-01

Aluminum-doped zinc oxide (AZO) has attained intensive attention as being a very good transparent conducting oxide for photovoltaic applications. In this work, AZO films have been deposited on glass substrate by radio frequency (RF) magnetron sputtering. The influences of substrate temperatures on morphological, structural, optical and electrical properties of AZO films were systematically investigated. The results indicate that all AZO films have the hexagonal structure with c-axis preferred orientation. Morphological and electrical measurements have revealed that the substrate temperatures have strong influence on the microstructure, optical and electrical properties of AZO films. The AZO film is highly transparent from ultraviolet up to near infrared range with highest average transparency exceeding 83%. The minimum resistivity is as low as 6.1 × 10-4 Ω cm. The carrier concentration and mobility are as high as 3.357 × 1020 cm-3 and 30.48 cm2/Vs, respectively. Finally, the performances of the AZO film are evaluated by its practical application in Cu(In1-xGax)Se2 (CIGS) photovoltaic device as a transparent electrode. Benefited from its highly transparent and conductive feature, the most efficient device reveals an efficiency of 7.8% with a short-circuit current density of 28.99 mA/cm2, an open-circuit voltage of 430 mV, and a fill factor of 62.44 under standard conditions.

Assessing electronic cigarette emissions: linking physico-chemical properties to product brand, e-liquid flavoring additives, operational voltage and user puffing patterns.

PubMed

Zhao, Jiayuan; Nelson, Jordan; Dada, Oluwabunmi; Pyrgiotakis, Georgios; Kavouras, Ilias G; Demokritou, Philip

2018-02-01

Users of electronic cigarettes (e-cigs) are exposed to particles and other gaseous pollutants. However, major knowledge gaps on the physico-chemical properties of such exposures and contradictory data in published literature prohibit health risk assessment. Here, the effects of product brand, type, e-liquid flavoring additives, operational voltage, and user puffing patterns on emissions were systematically assessed using a recently developed, versatile, e-cig exposure generation platform and state-of-the-art analytical methods. Parameters of interest in this systematic evaluation included two brands (A and B), three flavors (tobacco, menthol, and fruit), three types of e-cigs (disposable, pre-filled, and refillable tanks), two puffing protocols (4 and 2 s/puff), and four operational voltages (2.2-5.7 V). Particles were generated at a high number concentration (10 6 -10 7 particles/cm 3 ). The particle size distribution was bi-modal (∼200 nm and 1 µm). Furthermore, organic species (humectants propylene glycol and glycerin, nicotine) that were present in e-liquid and trace metals (potassium and sodium) that were present on e-cig heating coil were also released into the emission. In addition, combustion-related byproducts, such as benzene and toluene, were also detected in the range of 100-38,000 ppbv/puff. Parametric analyzes performed in this study show the importance of e-cig brand, type, flavor additives, user puffing pattern (duration and frequency), and voltage on physico-chemical properties of emissions. This observed influence is indicative of the complexity associated with the toxicological screening of emissions from e-cigs and needs to be taken into consideration.

Effects of intrinsic and extrinsic point defects on epitaxial single crystal copper-indium(1-x)-gallium(x)-diselenide

NASA Astrophysics Data System (ADS)

Schroeder, David James

From the results presented here a number of conclusions regarding the effects of point defects on the properties of epitaxial single crystal CuInsb{1-x}Gasb{x}Sesb2 (CIGS) may be drawn. These conclusions may be divided into three categories: the effects of point defects on Ga diffusion and diffusivity, the influence of impurities and alloying elements on doping and mobility, and the effects of impurities on minority carrier recombination kinetics. The diffusivity of Ga into CIGS during growth was found to be strongly dependent of the Cu/In ratio of the growing layer. Diffusivity ranged from a minimum of 2.7×10sp{-13}\\ cmsp2/s at Cu/In = 0.94 to 5 × 10sp{-11} cmsp2/s at Cu/In = 1.41 and 7×10sp{-12} cmsp2/s at Cu/In = 0.43. The diffusion occurred by a vacancy mechanism with Ga, apparently, diffusing through either Cu or In vacancies. The sharp change in diffusivity with changing Cu/In ratio helps to explain the difficulty in maintaining a desired Ga profile in polycrystalline CIGS device absorber layers. Increasing Ga content was found to increase both acceptor and donor density. The decrease in Jsbsc found in Ga-containing polycrystalline devices, is likely caused by a large increase in acceptor density, which may cause less inversion of the surface of the p-type CIGS making the junction more sensitive to surface states. The effect of adding Na by diffusion from either NaOH or Nasp2Se was to reduce the donor density. These results help to explain results in polycrystalline CIGS devices where Na increased hole concentrations, Vsboc, and device efficiency. Unlike Ga and Na, Cr and Se were not found to have any strong effect when added in concentrations ≤10sp{19} cmsp{-3} using ion implantation. The lack of an effect of Se on doping conclusively determines that Na has an effect beyond simply introducing either O or Se into the bulk of the CIGS. While both implanted Se and Cr created large numbers of donors and acceptors before being annealed, both caused a decrease in acceptor concentration after annealing with the effect of Cr being larger than that of Se. Both Se and Cr reduced hole mobility over the entire temperature range investigated. These results imply that CIGS-based devices should be insensitive to accidental transition metal contamination. The steady state photoconductivity of samples which had been ion implanted with Se and Cr, as well as samples which were contaminated with Na by diffusion, was measured. These measurements were made to determine whether contamination by these elements or severe radiation damage affects minority carrier recombination kinetics. In all cases the photoconductivity was found to be unaffected other than by changes in mobility. (Abstract shortened by UMI.)

The effects of Na on high pressure phases of CuIn(0.5)Ga(0.5)Se(2) from ab initio calculation.

PubMed

Pluengphon, P; Bovornratanaraks, T; Vannarat, S; Pinsook, U

2012-03-07

The effects of Na atoms on high pressure structural phase transitions of CuIn(0.5)Ga(0.5)Se(2) (CIGS) were studied by an ab initio method using density functional theory. At ambient pressure, CIGS is known to have chalcopyrite (I42d) structure. The high pressure phase transitions of CIGS were proposed to be the same as the order in the CuInSe(2) phase transitions which are I42d → Fm3m → Cmcm structures. By using the mixture atoms method, the Na concentration in CIGS was studied at 0.1, 1.0 and 6.25%. The positive mixing enthalpy of Na at In/Ga sites (Na(InGa)) is higher than that of Na at Cu sites (Na(Cu)). It confirmed previous studies that Na preferably substitutes on the Cu sites more than the (In, Ga) sites. From the energy-volume curves, we found that the effect of the Na substitutes is to reduce the hardness of CIGS under high pressure. The most significant effects occur at 6.25% Na. We also found that the electronic density of states of CIGS near the valence band maximum is increased noticeably in the chalcopyrite phase. The band gap is close in the cubic and orthorhombic phases. Also, the Na(Cu)-Se bond length in the chalcopyrite phase is significantly reduced at 6.25% Na, compared with the pure Cu-Se bond length. Consequently, the energy band gap in this phase is wider than in pure CIGS, and the gap increased at the rate of 31 meV GPa(-1) under pressure. The Na has a small effect on the transition pressure. The path of transformation from the cubic to orthorhombic phase was derived. The Cu-Se plane in the cubic phase displaced relatively parallel to the (In, Ga)-Se plane by 18% in order to transform to the Cmcm phase. The enthalpy barrier is 0.020 eV/atom, which is equivalent to a thermal energy of 248 K. We predicted that Fm3m and Cmcm can coexist in some pressure range.

The Coeliac Stomach: Gastritis in Patients with Coeliac Disease

PubMed Central

Lebwohl, Benjamin; Green, Peter HR; Genta, Robert M.

2015-01-01

Background Lymphocytic gastritis (LG) is an uncommon entity with varying symptoms and endoscopic appearances. This condition, as well as two forms of H. pylori-negative gastritis (chronic active gastritis [CAG] and chronic inactive gastritis [CIG]), appears to be more common in patients with coeliac disease (CD) based on single-center studies. Aim To compare the prevalence of LG, CAG, and CIG among those with normal duodenal histology (or non-specific duodenitis) and those with CD, as defined by villous atrophy (Marsh 3). Methods We analyzed all concurrent gastric and duodenal biopsy specimens submitted to a national pathology laboratory during a six-year period. We performed multiple logistic regression to identify independent predictors of each gastritis subtype. Results Among patients who underwent concurrent gastric and duodenal biopsy (n=287,503), the mean age was 52 and the majority (67%) was female. Compared to patients with normal duodenal histology, LG was more common inpartial villous atrophy (OR 37.66; 95% CI 30.16–47.03), and subtotal/total villous atrophy (OR 78.57; 95% CI 65.37–94.44). CD was also more common in CAG (OR for partial villous atrophy 1.93; 95%CI 1.49–2.51, OR for subtotal/total villous atrophy 2.42; 95%CI 1.90–3.09) and was similarly associated with CIG (OR for partial villous atrophy 2.04; 95%CI 1.76–2.35, OR for subtotal/total villous atrophy 2.96; 95% CI 2.60–3.38). Conclusion LG is strongly associated with CD, with increasing prevalence correlating with more advanced villous atrophy. CAG and CIG are also significantly associated with CD. Future researchshould measure the natural history of these conditions after treatment with a gluten-free diet. PMID:25973720

Laser microprocessing technologies for automotive, flexible electronics, and solar energy sectors

NASA Astrophysics Data System (ADS)

Nikumb, Suwas; Bathe, Ravi; Knopf, George K.

2014-10-01

Laser microprocessing technologies offer an important tool to fulfill the needs of many industrial sectors. In particular, there is growing interest in applications of these processes in the manufacturing areas such as automotive parts fabrication, printable electronics and solar energy panels. The technology is primarily driven by our understanding of the fundamental laser-material interaction, process control strategies and the advancement of significant fabrication experience over the past few years. The wide-ranging operating parameters available with respect to power, pulse width variation, beam quality, higher repetition rates as well as precise control of the energy deposition through programmable pulse shaping technologies, enables pre-defined material removal, selective scribing of individual layer within a stacked multi-layer thin film structure, texturing of material surfaces as well as precise introduction of heat into the material to monitor its characteristic properties are a few examples. In this research, results in the area of laser surface texturing of metals for added hydrodynamic lubricity to reduce friction, processing of ink-jet printed graphene oxide for flexible printed electronic circuit fabrication and scribing of multi-layer thin films for the development of photovoltaic CuInGaSe2 (CIGS) interconnects for solar panel devices will be discussed.

Finding the right match: Mindfulness training may potentiate the therapeutic effect of non-judgment of inner experience on smoking cessation

PubMed Central

Schuman-Olivier, Zev D.; Hoeppner, Bettina B.; Evins, A. Eden; Brewer, Judson

2014-01-01

Mindfulness Training (MT) is an emerging therapeutic modality for addictive disorders. Non-judgment of inner experience, a component of mindfulness, may influence addiction treatment response. To test whether this component influences smoking cessation, tobacco smokers (n=85) in a randomized control trial of MT vs. Freedom from Smoking (FFS), a standard cognitive-behaviorally-oriented treatment, were divided into split-half subgroups based on baseline Five Facet Mindfulness Questionnaire non-judgment subscale. Smokers who rarely judge inner experience (non-judgment > 30.5) smoked less during follow-up when randomized to MT (3.9 cigs/d) vs. FFS (11.1 cigs/d), p <0.01. Measuring trait non-judgment may help personalize treatment assignments, improving outcomes. PMID:24611853

Comparative Study of Zn(O,S) Buffer Layers and CIGS Solar Cells Fabricated by CBD, ALD, and Sputtering: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramanathan, K.; Mann, J.; Glynn, S.

2012-06-01

Zn(O,S) thin films were deposited by chemical bath deposition (CBD), atomic layer deposition, and sputtering. Composition of the films and band gap were measured and found to follow the trends described in the literature. CBD Zn(O,S) parameters were optimized and resulted in an 18.5% efficiency cell that did not require post annealing, light soaking, or an undoped ZnO layer. Promising results were obtained with sputtering. A 13% efficiency cell was obtained for a Zn(O,S) emitter layer deposited with 0.5%O2. With further optimization of process parameters and an analysis of the loss mechanisms, it should be possible to increase the efficiency.

The Importance of Conditioned Stimuli in Cigarette and E-Cigarette Craving Reduction by E-Cigarettes.

PubMed

Van Heel, Martijn; Van Gucht, Dinska; Vanbrabant, Koen; Baeyens, Frank

2017-02-15

This study examined the impact of four variables pertaining to the use of e-cigarettes (e-cigs) on cravings for tobacco cigarettes and for e-cigs after an overnight abstinence period. The four variables were the nicotine level, the sensorimotor component, the visual aspect, and the aroma of the e-cig. In an experimental study, 81 participants without prior vaping experience first got acquainted with using e-cigs in a one-week tryout period, after which they participated in a lab session assessing the effect of five minutes of vaping following an abstinence period of 12 h. A mixed-effects model clearly showed the importance of nicotine in craving reduction. However, also non-nicotine factors, in particular the sensorimotor component, were shown to contribute to craving reduction. Handling cues interacted with the level (presence/absence) of nicotine: it was only when the standard hand-to-mouth action cues were omitted that the craving reducing effects of nicotine were observed. Effects of aroma or visual cues were not observed, or weak and difficult to interpret, respectively.

Potential-induced degradation of Cu(In,Ga)Se2 photovoltaic modules

NASA Astrophysics Data System (ADS)

Yamaguchi, Seira; Jonai, Sachiko; Hara, Kohjiro; Komaki, Hironori; Shimizu-Kamikawa, Yukiko; Shibata, Hajime; Niki, Shigeru; Kawakami, Yuji; Masuda, Atsushi

2015-08-01

Potential-induced degradation (PID) of Cu(In,Ga)Se2 (CIGS) photovoltaic (PV) modules fabricated from integrated submodules is investigated. PID tests were performed by applying a voltage of -1000 V to connected submodule interconnector ribbons at 85 °C. The normalized energy conversion efficiency of a standard module decreases to 0.2 after the PID test for 14 days. This reveals that CIGS modules suffer PID under this experimental condition. In contrast, a module with non-alkali glass shows no degradation, which implies that the degradation occurs owing to alkali metal ions, e.g., Na+, migrating from the cover glass. The results of dynamic secondary ion mass spectrometry show Na accumulation in the n-ZnO transparent conductive oxide layer of the degraded module. A CIGS PV module with an ionomer (IO) encapsulant instead of a copolymer of ethylene and vinyl acetate shows no degradation. This reveals that the IO encapsulant can prevent PID of CIGS modules. A degraded module can recover from its performance losses by applying +1000 V to connected submodule interconnector ribbons from an Al plate placed on the test module.

The Importance of Conditioned Stimuli in Cigarette and E-Cigarette Craving Reduction by E-Cigarettes

PubMed Central

Van Heel, Martijn; Van Gucht, Dinska; Vanbrabant, Koen; Baeyens, Frank

2017-01-01

This study examined the impact of four variables pertaining to the use of e-cigarettes (e-cigs) on cravings for tobacco cigarettes and for e-cigs after an overnight abstinence period. The four variables were the nicotine level, the sensorimotor component, the visual aspect, and the aroma of the e-cig. In an experimental study, 81 participants without prior vaping experience first got acquainted with using e-cigs in a one-week tryout period, after which they participated in a lab session assessing the effect of five minutes of vaping following an abstinence period of 12 h. A mixed-effects model clearly showed the importance of nicotine in craving reduction. However, also non-nicotine factors, in particular the sensorimotor component, were shown to contribute to craving reduction. Handling cues interacted with the level (presence/absence) of nicotine: it was only when the standard hand-to-mouth action cues were omitted that the craving reducing effects of nicotine were observed. Effects of aroma or visual cues were not observed, or weak and difficult to interpret, respectively. PMID:28212302

{112} Polar surfaces of copper(indium,gallium)selenide: Properties and effects on crystal growth

NASA Astrophysics Data System (ADS)

Liao, Dongxiang

Cu(In,Ga)Se2 (GIGS) are promising materials for thin film photovoltaic applications. This work studies the epitaxial growth of CIGS single crystal films on GaAs substrates of various orientations and characterizes the properties of the thin films. A surprising finding is the strong tendency of film surfaces to facet to {112} planes. The work attempted to establish the connections between the film morphology, the surface energies, the surface chemical compositions, and the reconstruction of polar surfaces. Using angle-resolved photoelectron emission spectroscopy, I found that there is a severe Cu depletion at the first 1-2 layer of the free surface of CuInSe2 and the surface is semiconducting. The results strongly support the model of a reconstructed non-stoichiometric polar surface and exclude the previously believed existence of a bulk second phase on the CIS surface. Unique features of the film morphology suggest that the properties and structure of the polar surfaces have great effects on the growth of the crystals, and probably on the incorporation of the large amount of point defects. Measured chemical composition profiles indicate that the Cu depletion observed on free CIGS surface remains at the CIGS/CdS heterojunction interface and Cd is incorporated into the surface of CIGS. It is proposed that this non-stoichiometric composition leads to charge imbalance at the interface and causes the type-inversion of the CIGS surface, which are favorable for the device performance.

Solar Electricity and Solar Fuels: Status and Perspectives in the Context of the Energy Transition.

PubMed

Armaroli, Nicola; Balzani, Vincenzo

2016-01-04

The energy transition from fossil fuels to renewables is already ongoing, but it will be a long and difficult process because the energy system is a gigantic and complex machine. Key renewable energy production data show the remarkable growth of solar electricity technologies and indicate that crystalline silicon photovoltaics (PV) and wind turbines are the workhorses of the first wave of renewable energy deployment on the TW scale around the globe. The other PV alternatives (e.g., copper/indium/gallium/selenide (CIGS) or CdTe), along with other less mature options, are critically analyzed. As far as fuels are concerned, the situation is significantly more complex because making chemicals with sunshine is far more complicated than generating electric current. The prime solar artificial fuel is molecular hydrogen, which is characterized by an excellent combination of chemical and physical properties. The routes to make it from solar energy (photoelectrochemical cells (PEC), dye-sensitized photoelectrochemical cells (DSPEC), PV electrolyzers) and then synthetic liquid fuels are presented, with discussion on economic aspects. The interconversion between electricity and hydrogen, two energy carriers directly produced by sunlight, will be a key tool to distribute renewable energies with the highest flexibility. The discussion takes into account two concepts that are often overlooked: the energy return on investment (EROI) and the limited availability of natural resources-particularly minerals-which are needed to manufacture energy converters and storage devices on a multi-TW scale. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The AMIGA sample of isolated galaxies. IV. A catalogue of neighbours around isolated galaxies

NASA Astrophysics Data System (ADS)

Verley, S.; Odewahn, S. C.; Verdes-Montenegro, L.; Leon, S.; Combes, F.; Sulentic, J.; Bergond, G.; Espada, D.; García, E.; Lisenfeld, U.; Sabater, J.

2007-08-01

Context: Studies of the effects of environment on galaxy properties and evolution require well defined control samples. Such isolated galaxy samples have up to now been small or poorly defined. The AMIGA project (Analysis of the interstellar Medium of Isolated GAlaxies) represents an attempt to define a statistically useful sample of the most isolated galaxies in the local (z ≤ 0.05) Universe. Aims: A suitable large sample for the AMIGA project already exists, the Catalogue of Isolated Galaxies (CIG, Karachentseva, 1973, Astrofizicheskie Issledovaniia Izvestiya Spetsial'noj Astrofizicheskoj Observatorii, 8, 3; 1050 galaxies), and we use this sample as a starting point to refine and perform a better quantification of its isolation properties. Methods: Digitised POSS-I E images were analysed out to a minimum projected radius R ≥ 0.5 Mpc around 950 CIG galaxies (those within Vr = 1500 km s-1 were excluded). We identified all galaxy candidates in each field brighter than B = 17.5 with a high degree of confidence using the LMORPHO software. We generated a catalogue of approximately 54 000 potential neighbours (redshifts exist for ≈30% of this sample). Results: Six hundred sixty-six galaxies pass and two hundred eighty-four fail the original CIG isolation criterion. The available redshift data confirm that our catalogue involves a largely background population rather than physically associated neighbours. We find that the exclusion of neighbours within a factor of four in size around each CIG galaxy, employed in the original isolation criterion, corresponds to Δ Vr ≈ 18 000 km s-1 indicating that it was a conservative limit. Conclusions: Galaxies in the CIG have been found to show different degrees of isolation. We conclude that a quantitative measure of this is mandatory. It will be the subject of future work based on the catalogue of neighbours obtained here. Full Table [see full text] is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/470/505 and from http://www.iaa.es/AMIGA.html. Figure 4 is only available in electronic form at http://www.aanda.org

Development of Enhanced Window layers for CIGS Photovoltaic Devices

NASA Astrophysics Data System (ADS)

Alexander, J. Nicholas

One of the most promising thin film devices right now is the Copper Indium Gallium Selenide (CIGS) solar cell with maximum reported power conversion efficiency of 22.3%. The Transparent Conducting Oxide (TCO) which is the top layer of the CIGS device also known as the window layer, is responsible for collecting the electrons generated in the CIGS device and conducting them to the circuit. Development of a very low resistivity film with a high optical transmission is crucial for optimal performance of devices as well as the ability to be deployed without changes to their properties for several decades. Current TCOs such as indium tin oxide (ITO) and aluminum doped zinc oxide (AZO) are met with limitations with either using large amounts of expensive materials such as indium, often requiring and anneal step to obtain good conductivity, or have shown poor long term reliability. This thesis is focused on development of InZnO and zirconium doped InZnO as a potential replacement TCO to obtain high conductivity and high transmission like the leading TCOs without needing heated depositions, post deposition annealing, and maintain a good film reliability. Zirconium doping was employed to farther enhance both the optical and electrical properties through enhancement of the films high frequency permittivity of InZnO while providing improved reliability to the film. The films were grown through a mix of DC and RF co-sputtering. InZnO films were deposited at varying indium concentration ( 10-30%) and samples were able to achieve low resistivity ( 7x10-4 O-cm), high mobility (>30 cm2/v.s), high carrier concentration (>10 20 cm-3), while maintaining high transmission (> 80%) in the visible and near-infrared region. After zirconium was incorporated into the InZnO films by replacement of the ZnO target with a ZrO2/ZnO (5:95) target, films of Zr:InZnO were deposit through the same method to achieve films that maintained very similar electrical and optical properties. The little change found in the elerical and optical properties has strongly indicated that incorporation of zirconium into the InZnO thin film may not be replacing indium and zinc in the structure of the film and not influence the high frequency permittivity and carrier concentration of InZnO. It is also shown that the incorporation of zirconium does not indicate any detrimental effects on the properties of InZnO. To investigate film reliability, a custom damp-heat chamber was designed in this study to expose samples of InZnO/SLG (soda lime glass), Zr:InZnO/SLG, and AZO up to 5000 hours in approximately 85°C and 85% relative humidity to accelerate the degradation rate of the films. AZO was found to degrade very rapidly and enter MO resistance in approximately 1 week in this damp heat setup, while the majority of InZnO and Zr:InZnO films remained conductive through the entire experiment. It was found films showed improvements to their reliability with increases in film thickness and indium content, decreases in the amount of oxygen present in the films (containing more oxygen vacancies), and films incorporated with zirconium. Zirconium may not have had the desired impact to the electrical and optical properties, but by adding zirconium doping and tailoring oxygen incorporation, films of Zr:InZnO were able to show no significant change in several thousand hours exposed to the damp-heat environment. Films were also investigated by XPS and chemical analysis showed hydroxide formation, which similar to AZO is likely the reason for performance degradation. Even in samples that did not heavily change in electrical properties show indication of diffusion of moisture through the film which is a potential problem for degradation at the interfaces in completed CIGS devices. In Addition to the TCO studies, two other studies are performed in this work on CIGS and photovoltaic related work. First the CdS layer, which is part of the window layers, usually referred to as the n-type buffer layer, had an alternative deposition chemistry investigated. This new chemistry replacing thiourea with N-methylthiourea was used in a chemical bath deposition (CBD). This new chemistry yielded more controlled growth kinetics with a wider processing window. The films grown using this chemistry were more uniform than those grown with the standard process using thiourea. These uniform films were shown to have more complete surface coverage at very thin layers ( 20-30 nm). The second study investigated commercial modules of crystalline silicon, CIGS, and CdTe based technologies with a total system capacity of approximately 100 kW. The system is fitted with current, voltage, temperature, irradiance, and a complete weather station. The purpose of the system is to investigate different panel technologies and monitoring challenges in northeast climates and to track their degradation over time. (Abstract shortened by ProQuest.).

Conventional and Electronic cigarettes dysregulate the expression of iron transporters and detoxifying enzymes at the brain vascular endothelium: In Vivo Evidence of a Gender-Specific Cellular Response to Chronic Cigarette Smoke Exposure.

PubMed

Kaisar, Mohammad A; Sivandzade, Farzane; Bhalerao, Aditya; Cucullo, Luca

2018-06-04

It is well established that tobacco smoking is associated with vascular endothelial dysfunction in a causative and dose dependent manner primarily related to the tobacco smoke (TS) content of reactive oxygen species (ROS), nicotine, and oxidative stress (OS) -driven inflammation. Preclinical studies have also shown that nicotine (the principal e-liquid's ingredient used in e-cigarettes (e-Cigs) can also cause OS, exacerbation of cerebral ischemia and secondary brain injury. Likewise, chronic e-Cig vaping could be prodromal to vascular endothelial dysfunctions. Herein, we provide direct evidence that similarly to TS, e-Cig promotes mitochondrial depolarization in primary brain vascular endothelial cells as well as the vascular endothelial cell line bEnd3. In addition, both TS and e-Cig exposure upregulated the transmembrane iron exporter Slc40a1 (crucial to maintain cellular iron and redox homeostasis) and that of porphyrin importer Abcb6 (linked to accelerated atherosclerosis). We then investigated in vivo whether gender plays a role in how chronic TS affect vascular endothelial functions. Our results clearly show chronic TS exposure differentially impacts the expression levels of Phase-II enzymes as well as the iron transporters previously investigated in vitro. Although the physiological implications of the gender-specific differential responses to TS are not fully clear, they do demonstrate that gender is a risk factor that needs to be investigated when assessing the potential impact of chronic smoking and perhaps e-Cig vaping. Copyright © 2018. Published by Elsevier B.V.

Vaping cannabis (marijuana): parallel concerns to e-cigs?

PubMed Central

Budney, Alan J.; Sargent, James D.; Lee, Dustin C.

2016-01-01

The proliferation of vaporization (‘vaping’) as a method for administering cannabis raises many of the same public health issues being debated and investigated in relation to e-cigarettes (e-cigs). Good epidemiological data on the prevalence of vaping cannabis are not yet available, but with current trends towards societal approval of medicinal and recreational use of cannabis, the pros and cons of vaping cannabis warrant study. As with e-cigs, vaping cannabis portends putative health benefits by reducing harm from ingesting toxic smoke. Indeed, vaping is perceived and being sold as a safer way to use cannabis, despite the lack of data on the health effects of chronic vaping. Other perceived benefits include better taste, more efficient and intense effects and greater discretion which allows for use in more places. Unfortunately, these aspects of vaping could prompt an increased likelihood of trying cannabis, earlier age of onset, more positive initial experiences, and more frequent use, thereby increasing the probability of problematic use or addiction. Sales and marketing of vaping devices with no regulatory guidelines, especially related to advertising or product development targeting youth, parallels concerns under debate related to e-cigs and youth. Thus, the quandary of whether or not to promote vaping as a safer method of cannabis administration for those wishing to use cannabis, and how to regulate vaping and vaping devices, necessitates substantial investigation and discussion. Addressing these issues in concert with efforts directed towards e-cigs may save time and energy and result in a more comprehensive and effective public health policy on vaping. PMID:26264448

Vaping cannabis (marijuana): parallel concerns to e-cigs?

PubMed

Budney, Alan J; Sargent, James D; Lee, Dustin C

2015-11-01

The proliferation of vaporization ('vaping') as a method for administering cannabis raises many of the same public health issues being debated and investigated in relation to e-cigarettes (e-cigs). Good epidemiological data on the prevalence of vaping cannabis are not yet available, but with current trends towards societal approval of medicinal and recreational use of cannabis, the pros and cons of vaping cannabis warrant study. As with e-cigs, vaping cannabis portends putative health benefits by reducing harm from ingesting toxic smoke. Indeed, vaping is perceived and being sold as a safer way to use cannabis, despite the lack of data on the health effects of chronic vaping. Other perceived benefits include better taste, more efficient and intense effects and greater discretion which allows for use in more places. Unfortunately, these aspects of vaping could prompt an increased likelihood of trying cannabis, earlier age of onset, more positive initial experiences, and more frequent use, thereby increasing the probability of problematic use or addiction. Sales and marketing of vaping devices with no regulatory guidelines, especially related to advertising or product development targeting youth, parallels concerns under debate related to e-cigs and youth. Thus, the quandary of whether or not to promote vaping as a safer method of cannabis administration for those wishing to use cannabis, and how to regulate vaping and vaping devices, necessitates substantial investigation and discussion. Addressing these issues in concert with efforts directed towards e-cigs may save time and energy and result in a more comprehensive and effective public health policy on vaping. © 2015 Society for the Study of Addiction.

CuInGaSe{sub 2} nanoparticles by pulsed laser ablation in liquid medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendivil, M.I.; García, L.V.; Krishnan, B.

2015-12-15

Highlights: • CIGS nanocolloids were synthesized using PLAL technique. • Characterized their morphology, structure, composition and optical properties. • Morphologies were dependent on ablation wavelength and liquid medium. • Optical absorption and bandgap of these nanocolloids were tunable. - Abstract: Pulsed laser ablation in liquid medium (PLALM) is a nanofabrication technique to produce complex nanostructures. CuInGaSe{sub 2} (CIGS) is an alloy with applications in photovoltaic industry. In this work, we studied the effects of laser ablation wavelength, energy fluence and liquid medium on the properties of the CIGS nanoparticles synthesized by PLALM. The nanoparticles obtained were analyzed by transmission electronmore » microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS) and UV–vis absorption spectroscopy. XPS results confirmed the chemical states and composition of the ablated products. TEM analysis showed different morphologies for the nanomaterials obtained in different liquid media and ablation wavelengths. The optical properties for these CIGS nanocolloids were analyzed using UV–vis absorption spectroscopy. The results demonstrated the use of PLALM as a useful synthesis technique for nanoparticles of quaternary photovoltaic materials.« less

A picture is worth a thousand words: Electronic cigarette content on Instagram and Pinterest

PubMed Central

Lee, Alexander S.; Hart, Joy L.; Sears, Clara G.; Walker, Kandi L.; Siu, Allison; Smith, Courteney

2017-01-01

INTRODUCTION This study examined electronic cigarette (e-cig) content in visual materials posted on the social-media platforms Instagram and Pinterest. Both platforms allow users to upload pictures to the internet and share them globally. Users can search for pictures tagged with specific keywords and phrases. METHODS Using content analysis, this study identified themes in image postings of e-cigs on social media. During five weeks of data collection, keywords were used to identify pictures related to e-cigs. These pictures were then coded into one or more categories. RESULTS The three most popular categories for Instagram posts were marketing, customization and juices/flavors. The three most popular categories for Pinterest posts were customization, marketing and memes. CONCLUSIONS Because of the persuasive power of visuals, it is important to examine communication on Instagram and Pinterest as well as the specific visual messages communicated. Stores and manufacturers use these and similar platforms to communicate with users and potential users; thus it seems that marketers are capitalizing on opportunities for persuasive appeal. The results highlight the popularity of e-cig content on these two social media platforms and reveal an emphasis on marketing and customization. PMID:28815224

A picture is worth a thousand words: Electronic cigarette content on Instagram and Pinterest.

PubMed

Lee, Alexander S; Hart, Joy L; Sears, Clara G; Walker, Kandi L; Siu, Allison; Smith, Courteney

2017-07-01

This study examined electronic cigarette (e-cig) content in visual materials posted on the social-media platforms Instagram and Pinterest. Both platforms allow users to upload pictures to the internet and share them globally. Users can search for pictures tagged with specific keywords and phrases. Using content analysis, this study identified themes in image postings of e-cigs on social media. During five weeks of data collection, keywords were used to identify pictures related to e-cigs. These pictures were then coded into one or more categories. The three most popular categories for Instagram posts were marketing, customization and juices/flavors. The three most popular categories for Pinterest posts were customization, marketing and memes. Because of the persuasive power of visuals, it is important to examine communication on Instagram and Pinterest as well as the specific visual messages communicated. Stores and manufacturers use these and similar platforms to communicate with users and potential users; thus it seems that marketers are capitalizing on opportunities for persuasive appeal. The results highlight the popularity of e-cig content on these two social media platforms and reveal an emphasis on marketing and customization.

Modeling the instability behavior of thin film devices: Fermi Level Pinning

NASA Astrophysics Data System (ADS)

Moeini, Iman; Ahmadpour, Mohammad; Gorji, Nima E.

2018-05-01

We investigate the underlying physics of degradation/recovery of a metal/n-CdTe Schottcky junction under reverse or forward bias stressing conditions. We used Sah-Noyce-Shockley (SNS) theory to investigate if the swept of Fermi level pinning at different levels (under forward/reverse bias) is the origin of change in current-voltage characteristics of the device. This theory is based on Shockley-Read-Hall recombination within the depletion width and takes into account the interface defect levels. Fermi Level Pinning theory was primarily introduced by Ponpon and developed to thin film solar cells by Dharmadasa's group in Sheffield University-UK. The theory suggests that Fermi level pinning at multiple levels occurs due to high concentration of electron-traps or acceptor-like defects at the interface of a Schottky or pn junction and this re-arranges the recombination rate and charage collection. Shift of these levels under stress conditions determines the change in current-voltage characteristics of the cell. This theory was suggested for several device such as metal/n-CdTe, CdS/CdTe, CIGS/CdS or even GaAs solar cells without a modeling approach to clearly explain it's physics. We have applied the strong SNS modeling approach to shed light on Fermi Level Pinning theory. The modeling confirms that change in position of Fermi Level and it's pining in a lower level close to Valence band increases the recombination and reduces the open-circuit voltage. In contrast, Fermi Level pinning close to conduction band strengthens the electric field at the junction which amplifies the carrier collection and boosts the open-circuit voltage. This theory can well explain the stress effect on device characteristics of various solar cells or Schottky junctions by simply finding the right Fermi level pinning position at every specific stress condition.

Molecular characterization of çig köfte sold at retail in Ankara, Turkey, and evaluation of selected antimicrobials as ingredients to control foodborne pathogens in çig köfte during refrigerated storage

USDA-ARS?s Scientific Manuscript database

We surveyed cig kofte purchased from restaurants or retail establishments in Turkey and monitored viability of Shiga toxin-producing Escherichia coli (STEC), Salmonella spp., or Listeria monocytogenes inoculated into cig kofte formulated with buffered or distilled vinegar in our laboratory. Regardin...

Inflammatory Response and Barrier Dysfunction by Different e-Cigarette Flavoring Chemicals Identified by Gas Chromatography-Mass Spectrometry in e-Liquids and e-Vapors on Human Lung Epithelial Cells and Fibroblasts.

PubMed

Gerloff, Janice; Sundar, Isaac K; Freter, Robert; Sekera, Emily R; Friedman, Alan E; Robinson, Risa; Pagano, Todd; Rahman, Irfan

2017-03-01

Recent studies suggest that electronic cigarette (e-cig) flavors can be harmful to lung tissue by imposing oxidative stress and inflammatory responses. The potential inflammatory response by lung epithelial cells and fibroblasts exposed to e-cig flavoring chemicals in addition to other risk-anticipated flavor enhancers inhaled by e-cig users is not known. The goal of this study was to evaluate the release of the proinflammatory cytokine (interleukin-8 [IL-8]) and epithelial barrier function in response to different e-cig flavoring chemicals identified in various e-cig e-liquid flavorings and vapors by chemical characterization using gas chromatography-mass spectrometry analysis. Flavorings, such as acetoin (butter), diacetyl, pentanedione, maltol (malt), ortho-vanillin (vanilla), coumarin, and cinnamaldehyde in comparison with tumor necrosis factor alpha (TNFα), were used in this study. Human bronchial epithelial cells (Beas2B), human mucoepidermoid carcinoma epithelial cells (H292), and human lung fibroblasts (HFL-1) were treated with each flavoring chemical for 24 hours. The cells and conditioned media were then collected and analyzed for toxicity (viability %), lung epithelial barrier function, and proinflammatory cytokine IL-8 release. Cell viability was not significantly affected by any of the flavoring chemicals tested at a concentration of 10 μM to 1 mM. Acetoin and diacetyl treatment induced IL-8 release in Beas2B cells. Acetoin- and pentanedione-treated HFL-1 cells produced a differential, but significant response for IL-8 release compared to controls and TNFα. Flavorings, such as ortho-vanillin and maltol, induced IL-8 release in Beas2B cells, but not in H292 cells. Of all the flavoring chemicals tested, acetoin and maltol were more potent inducers of IL-8 release than TNFα in Beas2B and HFL-1 cells. Flavoring chemicals rapidly impaired epithelial barrier function in human bronchial epithelial cells (16-HBE) as measured by electric cell surface impedance sensing. Our findings suggest that some of the e-cig liquids/aerosols containing flavoring chemicals can cause significant loss of epithelial barrier function and proinflammatory response in lung cells.

Exploration of CIGAS Alloy System for Thin-Film Photovoltaics on Novel Lightweight and Flexible Substrates

NASA Technical Reports Server (NTRS)

Woods, Lawrence M.; Kalla, Ajay; Ribelin, Rosine

2007-01-01

Thin-film photovoltaics (TFPV) on lightweight and flexible substrates offer the potential for very high solar array specific power (W/kg). ITN Energy Systems, Inc. (ITN) is developing flexible TFPV blanket technology that has potential for specific power greater than 2000 W/kg (including space coatings) that could result in solar array specific power between 150 and 500 W/kg, depending on array size, when mated with mechanical support structures specifically designed to take advantage of the lightweight and flexible substrates.(1) This level of specific power would far exceed the current state of the art for spacecraft PV power generation, and meet the needs for future spacecraft missions.(2) Furthermore the high specific power would also enable unmanned aircraft applications and balloon or high-altitude airship (HAA) applications, in addition to modular and quick deploying tents for surface assets or lunar base power, as a result of the high power density (W/sq m) and ability to be integrated into the balloon, HAA or tent fabric. ITN plans to achieve the high specific power by developing single-junction and two-terminal monolithic tandem-junction PV cells using thin-films of high-efficiency and radiation resistant CuInSe2 (CIS) partnered with bandgap-tunable CIS-alloys with Ga (CIGS) or Al (CIAS) on novel lightweight and flexible substrates. Of the various thin-film technologies, single-junction and radiation resistant CIS and associated alloys with gallium, aluminum and sulfur have achieved the highest levels of TFPV device performance, with the best efficiency reaching 19.5% under AM1.5 illumination conditions and on thick glass substrates.(3) Thus, it is anticipated that single- and tandem-junction devices with flexible substrates and based on CIS and related alloys will achieve the highest levels of thin-film space and HAA solar array performance.

Morphology and structure evolution of Cu(In,Ga)S{sub 2} films deposited by reactive magnetron co-sputtering with electron cyclotron resonance plasma assistance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nie, Man, E-mail: man.nie@helmholtz-berlin.de; Ellmer, Klaus

2014-02-28

Cu(In,Ga)S{sub 2} (CIGS) films were deposited on Mo coated soda lime glass substrates using an electron cyclotron resonance plasma enhanced one-step reactive magnetron co-sputtering process (ECR-RMS). The crystalline quality and the morphology of the Cu(In,Ga)S{sub 2} films were investigated by X-ray diffraction, atomic force microscopy, scanning electron microscopy, and X-ray fluorescence. We also compared these CIGS films with films previously prepared without ECR assistance and find that the crystallinity of the CIGS films is correlated with the roughness evolution during deposition. Atomic force microscopy was used to measure the surface topography and to derive one-dimensional power spectral densities (1DPSD). Allmore » 1DPSD spectra of CIGS films exhibit no characteristic peak which is typical for the scaling of a self-affine surface. The growth exponent β, characterizing the roughness R{sub q} evolution during the film growth as R{sub q} ∼ d{sup β}, changes with film thickness. The root-mean-square roughness at low temperatures increases only slightly with a growth exponent β = 0.013 in the initial growth stage, while R{sub q} increases with a much higher exponent β = 0.584 when the film thickness is larger than about 270 nm. Additionally, we found that the H{sub 2}S content of the sputtering atmosphere and the Cu- to-(In + Ga) ratio has a strong influence of the morphology of the CIGS films in this one-step ECR-RMS process.« less

Structural defects and recombination behavior of excited carriers in Cu(In,Ga)Se2 solar cells

NASA Astrophysics Data System (ADS)

Yang, J.; Du, H. W.; Li, Y.; Gao, M.; Wan, Y. Z.; Xu, F.; Ma, Z. Q.

2016-08-01

The carriers' behavior in neutral region (NTR) and space charged region (SCR) of Cu(In,Ga)Se2 thin film based solar cells has been investigated by temperature dependent photoluminescence (PL-T), electroluminescence (EL-T) and current-voltage (IV-T) from 10 to 300 K. PL-T spectra show that three kinds of defects, namely VSe, InCu and (InCu+VCu), are localized within the band gap of NTR and SCR of CIGS layer, corresponding to the energy levels of EC-0.08, EC-0.20 and EC-0.25 eV, respectively. The InCu and (InCu+VCu) deep level defects are non-radiative recombination centers at room temperature. The IV-T and EL-T analysis reveals that the injection modes of electrons from ZnO conduction band into Cu(In,Ga)Se2 layer are tunneling, thermally-excited tunneling and thermionic emission under 10-40, 60-160, and 180-300 K, respectively. At 10-160 K, the electrons tunnel into (InCu+VCu) and Vse defect levels in band gap of SCR and the drifting is involved in the emission bands at 0.96 and 1.07 eV, which is the direct evidence for a tunneling assisted recombination. At 180-300 K, the electrons are directly injected into the Cu(In,Ga)Se2 conduction band, and the emission of 1.13 eV are ascribed to the transitions from the conduction band to the valence band.

Automated generation of patient-tailored electronic care pathways by translating computer-interpretable guidelines into hierarchical task networks.

PubMed

González-Ferrer, Arturo; ten Teije, Annette; Fdez-Olivares, Juan; Milian, Krystyna

2013-02-01

This paper describes a methodology which enables computer-aided support for the planning, visualization and execution of personalized patient treatments in a specific healthcare process, taking into account complex temporal constraints and the allocation of institutional resources. To this end, a translation from a time-annotated computer-interpretable guideline (CIG) model of a clinical protocol into a temporal hierarchical task network (HTN) planning domain is presented. The proposed method uses a knowledge-driven reasoning process to translate knowledge previously described in a CIG into a corresponding HTN Planning and Scheduling domain, taking advantage of HTNs known ability to (i) dynamically cope with temporal and resource constraints, and (ii) automatically generate customized plans. The proposed method, focusing on the representation of temporal knowledge and based on the identification of workflow and temporal patterns in a CIG, makes it possible to automatically generate time-annotated and resource-based care pathways tailored to the needs of any possible patient profile. The proposed translation is illustrated through a case study based on a 70 pages long clinical protocol to manage Hodgkin's disease, developed by the Spanish Society of Pediatric Oncology. We show that an HTN planning domain can be generated from the corresponding specification of the protocol in the Asbru language, providing a running example of this translation. Furthermore, the correctness of the translation is checked and also the management of ten different types of temporal patterns represented in the protocol. By interpreting the automatically generated domain with a state-of-art HTN planner, a time-annotated care pathway is automatically obtained, customized for the patient's and institutional needs. The generated care pathway can then be used by clinicians to plan and manage the patients long-term care. The described methodology makes it possible to automatically generate patient-tailored care pathways, leveraging an incremental knowledge-driven engineering process that starts from the expert knowledge of medical professionals. The presented approach makes the most of the strengths inherent in both CIG languages and HTN planning and scheduling techniques: for the former, knowledge acquisition and representation of the original clinical protocol, and for the latter, knowledge reasoning capabilities and an ability to deal with complex temporal and resource constraints. Moreover, the proposed approach provides immediate access to technologies such as business process management (BPM) tools, which are increasingly being used to support healthcare processes. Copyright © 2012 Elsevier B.V. All rights reserved.

Regional climate science: lessons and opportunities

NASA Astrophysics Data System (ADS)

Mote, P. W.; Miles, E. L.; Whitely Binder, L.

2008-12-01

Since its founding in 1995, the Climate Impacts Group (CIG) at the University of Washington (UW) has achieved remarkable success at translating global- and regional-scale science into forms and products that are useful to, and used by, decision-makers. From GCM scenarios to research on the connection between global climate patterns and locally important factors like floods and wildfires, CIG's strong physical science foundation is matched by a vigorous and successful outreach program. As a result, CIG and its partner the Office of Washington State Climatologist at UW have made substantial progress at bridging the gap between climate science and decision-making, and are deeply involved in advising all levels of government and many business interests on adapting to climate variability and change. This talk will showcase some of the specific activities and tools, describe lessons learned, and illustrate how such efforts fit into a "National Climate Service."

Grazing Incidence Cross-Sectioning of Thin-Film Solar Cells via Cryogenic Focused Ion Beam: A Case Study on CIGSe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sardashti, Kasra; Haight, Richard; Anderson, Ryan

2016-06-22

Cryogenic focused ion beam (Cryo-FIB) milling at near-grazing angles is employed to fabricate cross-sections on thin Cu(In,Ga)Se2 with >8x expansion in thickness. Kelvin probe force microscopy (KPFM) on sloped cross sections showed reduction in grain boundaries potential deeper into the film. Cryo Fib-KPFM enabled the first determination of the electronic structure of the Mo/CIGSe back contact, where a sub 100 nm thick MoSey assists hole extraction due to 45 meV higher work function. This demonstrates that CryoFIB-KPFM combination can reveal new targets of opportunity for improvement in thin-films photovoltaics such as high-work-function contacts to facilitate hole extraction through the backmore » interface of CIGS.« less

Back surface studies of Cu(In,Ga)Se2 thin film solar cells

NASA Astrophysics Data System (ADS)

Simchi, Hamed

Cu(In,Ga)Se2 thin film solar cells have attracted a lot of interest because they have shown the highest achieved efficiency (21%) among thin film photovoltaic materials, long-term stability, and straightforward optical bandgap engineering by changing relative amounts of present elements in the alloy. Still, there are several opportunities to further improve the performance of the Cu(In,Ga)Se2 devices. The interfaces between layers significantly affect the device performance, and knowledge of their chemical and electronic structures is essential in identifying performance limiting factors. The main goal of this research is to understand the characteristics of the Cu(In,Ga)Se2-back contact interface in order to design ohmic back contacts for Cu(In,Ga)Se2-based solar cells with a range of band gaps and device configurations. The focus is on developing either an opaque or transparent ohmic back contact via surface modification or introduction of buffer layers in the back surface. In this project, candidate back contact materials have been identified based on modeling of band alignments and surface chemical properties of the absorber layer and back contact. For the first time, MoO3 and WO 3 transparent back contacts were successfully developed for Cu(In,Ga)Se 2 solar cells. The structural, optical, and surface properties of MoO 3 and WO3 were optimized by controlling the oxygen partial pressure during reactive sputtering and post-deposition annealing. Valence band edge energies were also obtained by analysis of the XPS spectra and used to characterize the interface band offsets. As a result, it became possible to illuminate of the device from the back, resulting in a recently developed "backwall superstrate" device structure that outperforms conventional substrate Cu(In,Ga)Se2 devices in the absorber thickness range 0.1-0.5 microm. Further enhancements were achieved by introducing moderate amounts of Ag into the Cu(In,Ga)Se2 lattice during the co-evaporation method resulting in a 9.7% cell (with 0.3 microm thickness) which has the highest efficiency reported for ultrathin CIGS solar cells to date. In addition, sulfized back contacts including ITO-S and MoS 2 are compared. Interface properties of different contact layers with (Ag,Cu)(In,Ga)Se2 absorber layers with various Ga/(Ga+In) and Ag/(Ag+Cu) ratios are discussed based on the XPS analysis and thermodynamics of reactions.

Inflammatory Response and Barrier Dysfunction by Different e-Cigarette Flavoring Chemicals Identified by Gas Chromatography–Mass Spectrometry in e-Liquids and e-Vapors on Human Lung Epithelial Cells and Fibroblasts

PubMed Central

Gerloff, Janice; Sundar, Isaac K.; Freter, Robert; Sekera, Emily R.; Friedman, Alan E.; Robinson, Risa; Pagano, Todd

2017-01-01

Abstract Recent studies suggest that electronic cigarette (e-cig) flavors can be harmful to lung tissue by imposing oxidative stress and inflammatory responses. The potential inflammatory response by lung epithelial cells and fibroblasts exposed to e-cig flavoring chemicals in addition to other risk-anticipated flavor enhancers inhaled by e-cig users is not known. The goal of this study was to evaluate the release of the proinflammatory cytokine (interleukin-8 [IL-8]) and epithelial barrier function in response to different e-cig flavoring chemicals identified in various e-cig e-liquid flavorings and vapors by chemical characterization using gas chromatography–mass spectrometry analysis. Flavorings, such as acetoin (butter), diacetyl, pentanedione, maltol (malt), ortho-vanillin (vanilla), coumarin, and cinnamaldehyde in comparison with tumor necrosis factor alpha (TNFα), were used in this study. Human bronchial epithelial cells (Beas2B), human mucoepidermoid carcinoma epithelial cells (H292), and human lung fibroblasts (HFL-1) were treated with each flavoring chemical for 24 hours. The cells and conditioned media were then collected and analyzed for toxicity (viability %), lung epithelial barrier function, and proinflammatory cytokine IL-8 release. Cell viability was not significantly affected by any of the flavoring chemicals tested at a concentration of 10 μM to 1 mM. Acetoin and diacetyl treatment induced IL-8 release in Beas2B cells. Acetoin- and pentanedione-treated HFL-1 cells produced a differential, but significant response for IL-8 release compared to controls and TNFα. Flavorings, such as ortho-vanillin and maltol, induced IL-8 release in Beas2B cells, but not in H292 cells. Of all the flavoring chemicals tested, acetoin and maltol were more potent inducers of IL-8 release than TNFα in Beas2B and HFL-1 cells. Flavoring chemicals rapidly impaired epithelial barrier function in human bronchial epithelial cells (16-HBE) as measured by electric cell surface impedance sensing. Our findings suggest that some of the e-cig liquids/aerosols containing flavoring chemicals can cause significant loss of epithelial barrier function and proinflammatory response in lung cells. PMID:28337465

Formation of Me-O-Si covalent bonds at the interface between polysilazane and stainless steel

NASA Astrophysics Data System (ADS)

Amouzou, Dodji; Fourdrinier, Lionel; Maseri, Fabrizio; Sporken, Robert

2014-11-01

In earlier works, we demonstrated the potential of polysilazane (PSZ) coatings for a use as insulating layers in Cu(In,Ga)Se2 (CIGS) solar cells prepared on steels substrates and showed a good adhesion between PSZ coatings and both AISI316 and AISI430 steels. In the present paper, spectroscopic techniques are used to elucidate the reason of such adhesion. X-ray Photoelectron Spectroscopy (XPS) was used to investigate surfaces for the two steel substrates and showed the presence of metal oxides and metal hydroxides at the top surface. XPS has been also used to probe interfaces between substrates and PSZ, and metallosiloxane (Me-O-Si) covalent bonds have been detected. These results were confirmed by Infra-Red Reflection Absorption Spectroscopy (IRRAS) analyses since vibrations related to Cr-O-Si and Fe-O-Si compounds were detected. Thus, the good adhesion between steel substrates and PSZ coatings was explained by covalent bonding through chemical reactions between PSZ precursors and hydroxide functional groups present on top surface of the two types of steel. Based on these results, an adhesion mechanism between steel substrates and PSZ coatings is proposed.

A resistance ratio change phenomenon observed in Al doped ZnO (AZO)/Cu(In1-xGax)Se2/Mo resistive switching memory device

NASA Astrophysics Data System (ADS)

Guo, Tao; Sun, Bai; Mao, Shuangsuo; Zhu, Shouhui; Xia, Yudong; Wang, Hongyan; Zhao, Yong; Yu, Zhou

2018-03-01

In this work, the Cu(In1-xGax)Se2 (CIGS), Al doped ZnO (AZO) and Mo has been used for constructing a resistive switching device with AZO/CIGS/Mo sandwich structure grown on a transparent glass substrate. The device represents a high-performance memory characteristics under ambient temperature. In particularly, a resistance ratio change phenomenon have been observed in our device for the first time.

Survey of CIG Data Base Generation from Imagery.

DTIC Science & Technology

1980-09-01

world as measured by training transfer. There is no conclusive research as to therequired degree of realism or fidelity necessary to train. In order to...driving force behind emphasizing perceptual fidelity as opposed to realisn is the high cost of realism . Replication of all sensible attri- butes of the...and specification of visual simulation systems will con- tinue to je based on physical fidelity to the real world until those trade-offs on realism

Interfacial Modifiers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Ina; French, Roger H.

Our project objective in the first and only Budget Period was to demonstrate the potential of nm-scale organofunctional silane coatings as a method of extending the lifetime of PV materials and devices. Specifically, the target was to double the lifetime performance of a laminated Cu(In,Ga)Se2 (CIGS) cell under real-world and accelerated aging exposure conditions. Key findings are that modification of aluminum-doped zinc oxide (AZO) films (materials used as transparent conductive oxide (TCO) top contacts) resulted in decreased degradation of optical and electrical properties under damp heat (DH) exposure compared to un-modified AZO. The most significant finding is that modification ofmore » the AZO top contact of full CIGS devices resulted in significantly improved properties under DH exposure compared to un-modified devices, by a factor of 4 after 1000 h. Results of this one-year project have demonstrated that surface functionalization is a viable pathway for extending the lifetime of state-of-the-art CIGS devices.« less

Electronic cigarette aerosols and copper nanoparticles induce mitochondrial stress and promote DNA fragmentation in lung fibroblasts.

PubMed

Lerner, Chad A; Rutagarama, Pierrot; Ahmad, Tanveer; Sundar, Isaac K; Elder, Alison; Rahman, Irfan

2016-09-02

Oxidants or nanoparticles have recently been identified as constituents of aerosols released from various styles of electronic cigarettes (E-cigs). Cells in the lung may be directly exposed to these constituents and harbor reactive properties capable of incurring acute cell injury. Our results show mitochondria are sensitive to both E-cig aerosols and aerosol containing copper nanoparticles when exposed to human lung fibroblasts (HFL-1) using an Air-Liquid Interface culture system, evident by elevated levels of mitochondrial ROS (mtROS). Increased mtROS after aerosol exposure is associated with reduced stability of OxPhos electron transport chain (ETC) complex IV subunit and nuclear DNA fragmentation. Increased levels of IL-8 and IL-6 in HFL-1 conditioned media were also observed. These findings reveal both mitochondrial, genotoxic, and inflammatory stresses are features of direct cell exposure to E-cig aerosols which are ensued by inflammatory duress, raising a concern on deleterious effect of vaping. Copyright © 2016 Elsevier Inc. All rights reserved.

Copper indium gallium selenide (CIGS) photovoltaic devices made using multistep selenization of nanocrystal films.

PubMed

Harvey, Taylor B; Mori, Isao; Stolle, C Jackson; Bogart, Timothy D; Ostrowski, David P; Glaz, Micah S; Du, Jiang; Pernik, Douglas R; Akhavan, Vahid A; Kesrouani, Hady; Vanden Bout, David A; Korgel, Brian A

2013-09-25

The power conversion efficiency of photovoltaic devices made with ink-deposited Cu(InxGa1-x)Se2 (CIGS) nanocrystal layers can be enhanced by sintering the nanocrystals with a high temperature selenization process. This process, however, can be challenging to control. Here, we report that ink deposition followed by annealing under inert gas and then selenization can provide better control over CIGS nanocrystal sintering and yield generally improved device efficiency. Annealing under argon at 525 °C removes organic ligands and diffuses sodium from the underlying soda lime glass into the Mo back contact to improve the rate and quality of nanocrystal sintering during selenization at 500 °C. Shorter selenization time alleviates excessive MoSe2 formation at the Mo back contact that leads to film delamination, which in turn enables multiple cycles of nanocrystal deposition and selenization to create thicker, more uniform absorber films. Devices with power conversion efficiency greater than 7% are fabricated using the multiple step nanocrystal deposition and sintering process.

To what extent does adding tobacco to cannabis expose young users to nicotine?

PubMed

Bélanger, Richard E; Marclay, François; Berchtold, André; Saugy, Martial; Cornuz, Jacques; Suris, Joan-Carles

2013-11-01

To determine if mulling, the process of adding tobacco to cannabis for its consumption, exposes young cannabis users to significant levels of nicotine. This observational study performed in 2009-2010 among Swiss youths aged 16-25 years involved the completion of a self-administrated questionnaire and the collection of a urine sample on the same day. Measures of urinary cotinine were blindly performed using liquid chromatography coupled-mass spectrometry. A total of 197 eligible participants were divided in 3 groups based on their consumption profile in the past 5 days: 70 abstainers (ABS) not having used cigarettes or cannabis, 57 cannabis users adding tobacco to the cannabis they smoke (MUL) but not having smoked cigarettes, and 70 cigarette smokers (CIG) not having smoked cannabis. Exposure to nicotine was at its lowest among ABS with a mean (SE) cotinine level of 3.2 (1.4) ng/ml compared, respectively, with 214.6 (43.8) and 397.9 (57.4) for MUL and CIG (p < .001). While consumption profile appeared as the only significant factor of influence when examining nicotine exposure from the ABS and MUL participants on multivariate analysis, it did not result in substantial differences among MUL and CIG groups. Urinary cotinine levels found among MUL are high enough to indicate a significant exposure to nicotine originating from the mulling process. In line with our results, health professionals should pay attention to mulling as it is likely to influence cannabis and cigarette use as well as the efficacy of cessation interventions.

[The challenge of electronic cigarettes].

PubMed

Córdoba García, Rodrigo

2014-01-01

The electronic cigarette (e-cig) is a device with a conventional cigarette shape that releases a determined dose of nicotine vapour through an electronic heating process. The nicotine cartridges vary significantly in the amount of nicotine released, even within the same brand. Not all brands admit that they contain nicotine, but this is detected in the majority of units analysed. The e-cig usually contains a propellant, such as propylene glycol, which is a lung irritant. The short-term respiratory effect of the vapour of an e-cig is similar to that caused by the smoke of a cigarette, and is a cause of broncho-restriction. The majority of brands contain glycerine and at least one case of lipoid pneumonia has been detected due to this substance. Many brands contain traces of N-nitrosamines, heavy metals, and other products that are found in conventional cigarette smoke, but in a much higher proportion. There is currently no scientific evidence available that shows it is an effective device for quitting smoking, thus it should not be pro-actively recommended for this purpose, and may interfere with the use of demonstrated scientific evidence-based treatments for quitting smoking. It may have an undesirable effect on promoting the starting of smoking in adolescents or keeping adult smokers consuming nicotine and on gestural dependency. The toxicity of the vapour is not well known, but it is known that they are not innocuous, thus they should not be used in closed public spaces. Copyright © 2014 Elsevier España, S.L. All rights reserved.

France's State of the Art Distributed Optical Fibre Sensors Qualified for the Monitoring of the French Underground Repository for High Level and Intermediate Level Long Lived Radioactive Wastes.

PubMed

Delepine-Lesoille, Sylvie; Girard, Sylvain; Landolt, Marcel; Bertrand, Johan; Planes, Isabelle; Boukenter, Aziz; Marin, Emmanuel; Humbert, Georges; Leparmentier, Stéphanie; Auguste, Jean-Louis; Ouerdane, Youcef

2017-06-13

This paper presents the state of the art distributed sensing systems, based on optical fibres, developed and qualified for the French Cigéo project, the underground repository for high level and intermediate level long-lived radioactive wastes. Four main parameters, namely strain, temperature, radiation and hydrogen concentration are currently investigated by optical fibre sensors, as well as the tolerances of selected technologies to the unique constraints of the Cigéo's severe environment. Using fluorine-doped silica optical fibre surrounded by a carbon layer and polyimide coating, it is possible to exploit its Raman, Brillouin and Rayleigh scattering signatures to achieve the distributed sensing of the temperature and the strain inside the repository cells of radioactive wastes. Regarding the dose measurement, promising solutions are proposed based on Radiation Induced Attenuation (RIA) responses of sensitive fibres such as the P-doped ones. While for hydrogen measurements, the potential of specialty optical fibres with Pd particles embedded in their silica matrix is currently studied for this gas monitoring through its impact on the fibre Brillouin signature evolution.

France’s State of the Art Distributed Optical Fibre Sensors Qualified for the Monitoring of the French Underground Repository for High Level and Intermediate Level Long Lived Radioactive Wastes

PubMed Central

Delepine-Lesoille, Sylvie; Girard, Sylvain; Landolt, Marcel; Bertrand, Johan; Planes, Isabelle; Boukenter, Aziz; Marin, Emmanuel; Humbert, Georges; Leparmentier, Stéphanie; Auguste, Jean-Louis; Ouerdane, Youcef

2017-01-01

This paper presents the state of the art distributed sensing systems, based on optical fibres, developed and qualified for the French Cigéo project, the underground repository for high level and intermediate level long-lived radioactive wastes. Four main parameters, namely strain, temperature, radiation and hydrogen concentration are currently investigated by optical fibre sensors, as well as the tolerances of selected technologies to the unique constraints of the Cigéo’s severe environment. Using fluorine-doped silica optical fibre surrounded by a carbon layer and polyimide coating, it is possible to exploit its Raman, Brillouin and Rayleigh scattering signatures to achieve the distributed sensing of the temperature and the strain inside the repository cells of radioactive wastes. Regarding the dose measurement, promising solutions are proposed based on Radiation Induced Attenuation (RIA) responses of sensitive fibres such as the P-doped ones. While for hydrogen measurements, the potential of specialty optical fibres with Pd particles embedded in their silica matrix is currently studied for this gas monitoring through its impact on the fibre Brillouin signature evolution. PMID:28608831

In-situ X-Ray Analysis of Rapid Thermal Processing for Thin-Film Solar Cells: Closing the Gap between Production and Laboratory Efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toney, Michael F.; van Hest, Maikel F. A. M.

For materials synthesis, it is well known that the material final state may not reach equilibrium and depends on the synthetic process. In particular, processes that quickly remove the available energy from the material may leave it in a metastable state and the metastability may actually impart desirable functional properties. By its very nature, Rapid thermal processing (RTP) is ideally suited to produce such metastable materials. However, metastability and the dynamics of reaching a metastable state are poorly understood, since this is best accomplished through in situ monitoring. In this regard, RTP is particularly challenging as the processing time aremore » very short (seconds to minutes). As a result, there is only poor understanding, and hence use, of RTP in industry. This is potentially a cost-increasing limitation, because RTP can decrease cost by decreasing processing time, and as such, increase throughput and decrease the total thermal budget of processing - a significant cost. RTP is already being used for key processing steps in PV technologies. With silicon wafer PV, it is used for establishing electrical contact between the Ag metal grid and the silicon (known as firing). In this process, a silicon wafer with deposited metal/frit in a grid pattern is heated rapidly to temperatures between 750 and 800 ºC. The processing time when the temperature is held above 600ºC is short (<5 seconds). This process has historically been optimized empirically and it is unclear how the thermal processing affects formation of the final contact between the metal and the silicon. In the case of thin-film PV, RTP has been demonstrated in the process of making absorber layers, i.e. CIGS and CZTS. Use of RTP can reduce the processing time from 10s of minutes to seconds, reducing the thermal budget and increasing the throughput significantly. The conversion from precursor material to final PV material is not well understood, and most of the process optimization is done empirically. Again, the proposed in situ monitoring will provide insight into the conversion process. We have developed a unique instrument for in situ monitoring of the reaction process during RTP. The most fundamental property to monitor is the atomic arrangement (for solids, crystalline structure) and thus we have focused on this property. The chamber was designed to collect X-ray diffraction (XRD) for crystal phase determination, although it has lent insight in the formation of liquids. We designed and constructed both inert (air) and reactive (S/Se) versions of this chamber. We have applied the RTP-XRD methodology to: silicon solar cell electrical contact formation; the reaction sequence for forming CIGS PV thin films from copper selenide and indium gallium selenide precursors; the phase sequence for forming HC(NH2)2PbI3 (FAPbI3) and CH3NH3PbI3 (MAPbI3) hybrid-perovskite PV thin films. The RTP instrument enables real-time collection of X-ray diffraction data with intervals as short as 100 ms, and while heating at ramp rates as high 100 ºCs-1 up to 1200 ºC. The system is portable and can be installed on a synchrotron beamline. The RTP reactor consists of a metallic body (front cap assembly, central block and end cap assembly) that houses a quartz reaction chamber. The sample is secured inside the reaction chamber on a sample holder connected to the front-cap assembly. Modifications of the chamber were made for safely handling sulfur and selenium vapor environments. A Se/S source holder was added to generate a Se/S over pressure in the chamber on heating and the entrance window is made wider in order to accommodate the detachable additional holder. Se/S are toxic in nature and therefore a proper Se/S trapping is used before releasing the gases to exhaust. Screen-printing provides an economically attractive means for making Ag electrical contacts to Si solar cells, but the use of Ag substantiates a significant manufacturing cost, and the glass frit used in the paste to enable contact formation contains Pb. To achieve optimal electrical performance and to develop pastes with alternative, abundant, and non-toxic materials requires understanding the contact formation process during firing. We use the RTP-XRD chamber during firing of Ag-Si contacts to reveal the reaction sequence for contact formation. The findings show that between 500 ºC and 650 ºC PbO in the frit etches the SiNx antireflective-coating on the solar cell, exposing the Si surface. Then, above 650 ºC, Ag+ dissolves into the molten glass frit – key for enabling deposition of metallic Ag on the emitter surface and precipitation of Ag nanocrystals within the glass. This clarifies contact formation mechanisms and can be used to suggest approaches for development of inexpensive, nontoxic solar cell contacting pastes. We used the RTP/XRD chamber to study the formation of CuInGaS/Se (CIGS) PV films by in-situ selenization of pre-deposited metal stacks and annealing of pre-deposited Cu-In-Ga-Se precursors. During the metal stack selenization, we observed that Se first reacts with the metals and forms selenides. We observed formation of intermetallics such as Cu2In and binary selenides during heating. On further annealing in a Se atmosphere, CuInSe2 and CuGaSe2 forms which on heating up to 550 °C reacts further to form the CIGS phase. On prolonged exposure to 550 °C for more than 5 mins or higher temperature, we see separation into Ga-rich and Ga-depleted CIGS phases. On introducing a holding step at 400 °C for 10 min during the annealing ramp, the CIGS phase (forms between 500-550 °C), appears to be less prone to decomposition into high-Ga and low-Ga phases during holding at peak temperature. Lead halide perovskites have emerged as successful optoelectronic materials with high photovoltaic power conversion efficiencies and low material cost. However, substantial challenges remain in the scalability, stability and fundamental understanding of the materials. We demonstrated the application of radiative thermal annealing, an easily scalable processing method, for synthesizing formamidinium lead iodide (FAPbI3) perovskite solar absorbers. Devices fabricated from films formed via radiative thermal annealing have equivalent efficiencies to those annealed using a conventional hotplate. By coupling results from in situ x-ray diffraction using a radiative thermal annealing system with device performances, we mapped the processing phase space of FAPbI3 and corresponding device efficiencies. Our map of processing-structure-performance space suggests the commonly used FAPbI3 annealing time, 10 min at 170 °C, can be significantly reduced to 40 s at 170 °C without affecting the photovoltaic performance. Applying the Johnson-Mehl-Avrami model to the decomposition into PbI2, the activation energy was determined. We also presented a well-controlled, manufacturing relevant annealing method, radiative thermal annealing, for the methylammonium lead triiodide films formed by solvent engineering process, with dimethylformamide (DMF) and dimethyl sulfoxide as solvent and diethyl ether as the antisolvent. Radiative thermal annealing can produce high quality perovskite films, evidenced by high efficiency solar cell devices, in a shorter time than the widely-used hotplate annealing. Using in-situ x-ray diffraction during the radiative annealing, we show that the role of the antisolvent is not to form an intermediate compound (a methylammonium iodide, lead iodide, and dimethyl sulfoxide compound) by washing of the main solvent (DMF) but to achieve a pin-hole free, uniform film of methylammonium lead iodide. We find that having the intermediate compound does not guarantee a high quality (pin-hole free) perovskite film. Our study was extended to reveal the effect of annealing environment, annealing temperature profile, and deposition substrate.« less

Quantum efficiency as a device-physics interpretation tool for thin-film solar cells

NASA Astrophysics Data System (ADS)

Nagle, Timothy J.

2007-12-01

Thin-film solar cells made from CdTe and CIGS p-type absorbers are promising candidates for generating pollution-free electricity. The challenge faced by the thin-film photovoltaics (PV) community is to improve the electrical properties of devices, without straying from low-cost, industry-friendly techniques. This dissertation will focus on the use of quantum-efficiency (QE) measurements to deduce the device physics of thin-film devices, in the hope of improving electrical properties and efficiencies of PV materials. Photons which are absorbed, but not converted into electrical energy can modify the energy bands in the solar cell. Under illumination, photoconductivity in the CdS window layer can result in bands different from those in the dark. QE data presented here was taken under a variety of light-bias conditions. These results suggest that 0.10 sun of white-light bias incident on the CdS layer is usually sufficient to achieve accurate QE results. QE results are described by models based on carrier collection by drift and diffusion, and photon absorption. These models are sensitive to parameters such as carrier mobility and lifetime. Comparing calculated QE curves with experiments, it was determined that electron lifetimes in CdTe are less than 0.1 ns. Lifetime determinations also suggest that copper serves as a recombination center in CdTe. The spatial uniformity of QE results has been investigated with the LBIC apparatus, and several experiments are described which investigate cell uniformity. Electrical variations that occur in solar cells often occur in a nonuniform fashion, and can be detected with the LBIC apparatus. Studies discussed here include investigation of patterned deposition of Cu in back-contacts, the use of high-resistivity TCO layers to mitigate nonuniformity, optical effects, and local shunts. CdTe devices with transparent back contacts were also studied with LBIC, including those that received a strong bromine/dichrol/hydrazine (BDH) etch and those that received a weak bromine etch at the back contact. Back-side results showed improved uniformity in BDH-etched devices, attributed to better back contacts in these devices. In thin-absorber devices, the uniformity trend would likely extend to front-side measurements.

CCQM Pilot Study CCQM-P140: Quantitative surface analysis of multi-element alloy films

NASA Astrophysics Data System (ADS)

Kim, Kyung Joong; Jang, Jong Shik; Kim, An Soon; Suh, Jung Ki; Chung, Yong-Duck; Hodoroaba, Vasile-Dan; Wirth, Thomas; Unger, Wolfgang; Kang, Hee Jae; Popov, Oleg; Popov, Inna; Kuselman, Ilya; Lee, Yeon Hee; Sykes, David E.; Wang, Meiling; Wang, Hai; Ogiwara, Toshiya; Nishio, Mitsuaki; Tanuma, Shigeo; Simons, David; Szakal, Christopher; Osborn, William; Terauchi, Shinya; Ito, Mika; Kurokawa, Akira; Fujimoto, Toshiyuki; Jordaan, Werner; Jeong, Chil Seong; Havelund, Rasmus; Spencer, Steve; Shard, Alex; Streeck, Cornelia; Beckhoff, Burkhard; Eicke, Axel; Terborg, Ralf

2015-01-01

A pilot study for a quantitative surface analysis of multi-element alloy films has been performed by the Surface Analysis Working Group (SAWG) of the Consultative Committee for Amount of Substance (CCQM). The aim of this pilot study is to evaluate a protocol for a key comparison to demonstrate the equivalence of measures by National Metrology Institutes (NMIs) and Designated Institutes (DI) for the mole fractions of multi-element alloy films. A Cu(In,Ga)Se2 (CIGS) film with non-uniform depth distribution was chosen as a representative multi-element alloy film. The mole fractions of the reference and the test CIGS films were certified by isotope dilution—inductively coupled plasma/mass spectrometry. A total number counting (TNC) method was used as a method to determine the signal intensities of the constituent elements acquired in SIMS, XPS and AES depth profiling. TNC method is comparable with the certification process because the certified mole fractions are the average values of the films. The mole fractions of the CIGS films were measured by Secondary Ion Mass Spectrometry (SIMS), Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS), X-Ray Fluorescence (XRF) Analysis and Electron Probe Micro Analysis (EPMA) with Energy Dispersive X-ray Spectrometry (EDX). Fifteen laboratories from eight NMIs, one DI, and six non-NMIs participated in this pilot study. The average mole fractions of the reported data showed relative standard deviations from 5.5 % to 6.8 % and average relative expanded uncertainties in the range from 4.52 % to 4.86 % for the four test CIGS specimens. These values are smaller than those in the key comparison CCQM-K67 for the measurement of mole fractions of Fe-Ni alloy films. As one result it can be stated that SIMS, XPS and AES protocols relying on the quantification of CIGS films using the TNC method are mature to be used in a CCQM key comparison. Main text. To reach the main text of this paper, click on Final Report. The final report has been peer-reviewed and approved for publication by CCQM.

A fresh look at tobacco harm reduction: the case for the electronic cigarette

PubMed Central

2013-01-01

Smokers of any age can reap substantial health benefits by quitting. In fact, no other single public health effort is likely to achieve a benefit comparable to large-scale smoking cessation. Surveys document that most smokers would like to quit, and many have made repeated efforts to do so. However, conventional smoking cessation approaches require nicotine addicted smokers to abstain from tobacco and nicotine entirely. Many smokers are unable – or at least unwilling – to achieve this goal, and so they continue smoking in the face of impending adverse health consequences. In effect, the status quo in smoking cessation presents smokers with just two unpleasant alternatives: quit or suffer the harmful effects of continuing smoking. But, there is a third choice for smokers: tobacco harm reduction. It involves the use of alternative sources of nicotine, including modern smokeless tobacco products like snus and the electronic cigarette (E-cig), or even pharmaceutical nicotine products, as a replacement for smoking. E-cigs might be the most promising product for tobacco harm reduction to date, because, besides delivering nicotine vapour without the combustion products that are responsible for nearly all of smoking’s damaging effect, they also replace some of the rituals associated with smoking behaviour. Thus it is likely that smokers who switch to E-cigs will achieve large health gains. The focus of this article is on the health effects of using an E-cig, with consideration given to the acceptability, safety and effectiveness of this product as a long-term substitute for smoking. PMID:24090432

E-cigarettes as a source of toxic and potentially carcinogenic metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hess, Catherine Ann, E-mail: chess@prev.org

Background and aims: The popularity of electronic cigarette devices is growing worldwide. The health impact of e-cigarette use, however, remains unclear. E-cigarettes are marketed as a safer alternative to cigarettes. The aim of this research was the characterization and quantification of toxic metal concentrations in five, nationally popular brands of cig-a-like e-cigarettes. Methods: We analyzed the cartomizer liquid in 10 cartomizer refills for each of five brands by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Results: All of the tested metals (cadmium, chromium, lead, manganese and nickel) were found in the e-liquids analyzed. Across all analyzed brands, mean (SD) concentrations rangedmore » from 4.89 (0.893) to 1970 (1540) μg/L for lead, 53.9 (6.95) to 2110 (5220) μg/L for chromium and 58.7 (22.4) to 22,600 (24,400) μg/L for nickel. Manganese concentrations ranged from 28.7 (9.79) to 6910.2 (12,200) μg/L. We found marked variability in nickel and chromium concentration within and between brands, which may come from heating elements. Conclusion: Additional research is needed to evaluate whether e-cigarettes represent a relevant exposure pathway for toxic metals in users. - Highlights: • Certain brands of cig-a-like e-cigarettes contain high levels of nickel and chromium. • Cig-a-likes contain low levels of cadmium, compared to tobacco cigarettes. • Nickel and chromium in the e-liquid of cig-a-likes may come from nichrome heating coils.« less

E-cigarette vapour is not inert and exposure can lead to cell damage.

PubMed

Holliday, Richard; Kist, Ralf; Bauld, Linda

2016-03-01

In vitro experiments were performed on normal epithelial cells as well as head and neck squamous cell carcinoma (HNSCC) cell lines. The widely available cell line HaCat, a spontaneously transformed immortal keratinocyte and the HNSCC cell lines HN30 and UMSCC10B were used. Cells were exposed to nicotine-containing and nicotine-free vapour extract from two popular e-cigarette brands for periods ranging from 48 hours to eight weeks. Cytotoxicity was assessed using Annexin V flow cytometric analysis, trypan blue exclusion and clonogenic assays. Genotoxicity in the form of DNA strand breaks was quantified using the neutral comet assay and γ-H2AX immunostaining. E-cigarette-exposed cells showed significantly reduced cell viability and clonogenic survival, along with increased rates of apoptosis and necrosis, regardless of e-cigarette vapour nicotine content. They also exhibited significantly increased comet tail length and accumulation of γ-H2AX foci, demonstrating increased DNA strand breaks. In conclusion, our study strongly suggests that electronic cigarettes are not as safe as their marketing makes them appear to the public. Our in vitro experiments employing two brands of e-cigs show that at biologically relevant doses, vapourised e-cig liquids induce increased DNA strand breaks and cell death, and decreased clono- genic survival in both normal epithelial and HNSCC cell lines independently of nicotine content. Further research is needed to definitively determine the long-term effects of e-cig usage, as well as whether the DNA damage shown in our study as a result of e-cig exposure will lead to mutations that ultimately result in cancer.

Design of optimal buffer layers for CuInGaSe2 thin-film solar cells(Conference Presentation)

NASA Astrophysics Data System (ADS)

Lordi, Vincenzo; Varley, Joel B.; He, Xiaoqing; Rockett, Angus A.; Bailey, Jeff; Zapalac, Geordie H.; Mackie, Neil; Poplavskyy, Dmitry; Bayman, Atiye

2016-09-01

Optimizing the buffer layer in manufactured thin-film PV is essential to maximize device efficiency. Here, we describe a combined synthesis, characterization, and theory effort to design optimal buffers based on the (Cd,Zn)(O,S) alloy system for CIGS devices. Optimization of buffer composition and absorber/buffer interface properties in light of several competing requirements for maximum device efficiency were performed, along with process variations to control the film and interface quality. The most relevant buffer properties controlling performance include band gap, conduction band offset with absorber, dopability, interface quality, and film crystallinity. Control of an all-PVD deposition process enabled variation of buffer composition, crystallinity, doping, and quality of the absorber/buffer interface. Analytical electron microscopy was used to characterize the film composition and morphology, while hybrid density functional theory was used to predict optimal compositions and growth parameters based on computed material properties. Process variations were developed to produce layers with controlled crystallinity, varying from amorphous to fully epitaxial, depending primarily on oxygen content. Elemental intermixing between buffer and absorber, particularly involving Cd and Cu, also is controlled and significantly affects device performance. Secondary phase formation at the interface is observed for some conditions and may be detrimental depending on the morphology. Theoretical calculations suggest optimal composition ranges for the buffer based on a suite of computed properties and drive process optimizations connected with observed film properties. Prepared by LLNL under Contract DE-AC52-07NA27344.

Different ligand exchange solvents effect on the densification of CuIn0.7Ga0.3Se2 prepared using the heating-up method

NASA Astrophysics Data System (ADS)

Yang, Chang-Ting; Hsiang, Hsing-I.

2017-12-01

The effects of different ligand exchange solvents and heat treatment conditions on the densification and microstructure development of CuIn0.7Ga0.3Se2 (CIGS) crystallites synthesized using the heating-up method were studied in this work. The heat treatment effects on the organic molecules and crystalline structure were investigated using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was observed that oleylamine (OLA) adsorbed onto the CIGS surface was difficult to remove during sintering. Ligand-exchange with m-xylene or 1-hexanethiol can promote the removal of oleylamine adsorbed onto the CIGS surface and prevent the residual carbon from forming during sintering, which leads to grain growth and densification. A dense CuIn0.7Ga0.3Se2 can be obtained using the precursor powders after ligand-exchange with 1-hexanethiol and m-xylene to remove organic molecules and sintering at 600 °C for 2 h under Se atmosphere.

Flexible Ultra Moisture Barrier Film for Thin-Film Photovoltaic Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

David M. Dean

2012-10-30

Flexible Thin-film photovoltaic (TFPV) is a low cost alternative to incumbent c-Si PV products as it requires less volume of costly semiconductor materials and it can potentially reduce installation cost. Among the TFPV options, copper indium gallium diselenide (CIGS) has the highest efficiency and is believed to be one of the most attractive candidates to achieve PV cost reduction. However, CIGS cells are very moisture sensitive and require module water vapor transmission rate (WVTR) of less than 1x10-4 gram of water per square meter per day (g-H2O/m2/day). Successful development and commercialization of flexible transparent ultra moisture barrier film is themore » key to enable flexible CIGS TFPV products, and thus enable ultimate PV cost reduction. At DuPont, we have demonstrated at lab scale that we can successfully make polymer-based flexible transparent ultra moisture barrier film by depositing alumina on polymer films using atomic layer deposition (ALD) technology. The layer by layer ALD approach results in uniform and amorphous structure which effectively reduces pinhole density of the inorganic coating on the polymer, and thus allow the fabrication of flexible barrier film with WVTR of 10-5 g-H2O/m2/day. Currently ALD is a time-consuming process suitable only for high-value, relatively small substrates. To successfully commercialize the ALD-on-plastic technology for the PV industry, there is the need to scale up this technology and improve throughput. The goal of this contract work was to build a prototype demonstrating that the ALD technology could be scaled-up for commercial use. Unfortunately, the prototype failed to produce an ultra-barrier film by the close of the project.« less

The coeliac stomach: gastritis in patients with coeliac disease.

PubMed

Lebwohl, B; Green, P H R; Genta, R M

2015-07-01

Lymphocytic gastritis (LG) is an uncommon entity with varying symptoms and endoscopic appearances. This condition, as well as two forms of H. pylori-negative gastritis [chronic active gastritis (CAG) and chronic inactive gastritis (CIG)], appears to be more common in patients with coeliac disease (CD) based on single-centred studies. To compare the prevalence of LG, CAG and CIG among those with normal duodenal histology (or nonspecific duodenitis) and those with CD, as defined by villous atrophy (Marsh 3). We analysed all concurrent gastric and duodenal biopsy specimens submitted to a national pathology laboratory during a 6-year period. We performed multiple logistic regression to identify independent predictors of each gastritis subtype. Among patients who underwent concurrent gastric and duodenal biopsy (n = 287,503), the mean age was 52 and the majority (67%) were female. Compared to patients with normal duodenal histology, LG was more common in partial villous atrophy (OR: 37.66; 95% CI: 30.16-47.03), and subtotal/total villous atrophy (OR: 78.57; 95% CI: 65.37-94.44). CD was also more common in CAG (OR for partial villous atrophy 1.93; 95% CI: 1.49-2.51, OR for subtotal/total villous atrophy 2.42; 95% CI: 1.90-3.09) and was similarly associated with CIG (OR for partial villous atrophy 2.04; 95% CI: 1.76-2.35, OR for subtotal/total villous atrophy 2.96; 95% CI: 2.60-3.38). Lymphocytic gastritis is strongly associated with coeliac disease, with increasing prevalence correlating with more advanced villous atrophy. Chronic active gastritis and chronic inactive gastritis are also significantly associated with coeliac disease. Future research should measure the natural history of these conditions after treatment with a gluten-free diet. © 2015 John Wiley & Sons Ltd.

Interfacial Engineering and Charge Carrier Dynamics in Extremely Thin Absorber Solar Cells

NASA Astrophysics Data System (ADS)

Edley, Michael

Photovoltaic energy is a clean and renewable source of electricity; however, it faces resistance to widespread use due to cost. Nanostructuring decouples constraints related to light absorption and charge separation, potentially reducing cost by allowing a wider variety of processing techniques and materials to be used. However, the large interfacial areas also cause an increased dark current which negatively affects cell efficiency. This work focuses on extremely thin absorber (ETA) solar cells that used a ZnO nanowire array as a scaffold for an extremely thin CdSe absorber layer. Photoexcited electrons generated in the CdSe absorber are transferred to the ZnO layer, while photogenerated holes are transferred to the liquid electrolyte. The transfer of photoexcited carriers to their transport layer competes with bulk recombination in the absorber layer. After charge separation, transport of charge carriers to their respective contacts must occur faster than interfacial recombination for efficient collection. Charge separation and collection depend sensitively on the dimensions of the materials as well as their interfaces. We demonstrated that an optimal absorber thickness can balance light absorption and charge separation. By treating the ZnO/CdSe interface with a CdS buffer layer, we were able to improve the Voc and fill factor, increasing the ETA cell's efficiency from 0.53% to 1.34%, which is higher than that achievable using planar films of the same material. We have gained additional insight into designing ETA cells through the use of dynamic measurements. Ultrafast transient absorption spectroscopy revealed that characteristic times for electron injection from CdSe to ZnO are less than 1 ps. Electron injection is rapid compared to the 2 ns bulk lifetime in CdSe. Optoelectronic measurements such as transient photocurrent/photovoltage and electrochemical impedance spectroscopy were applied to study the processes of charge transport and interfacial recombination. With these techniques, the extension of the depletion layer from CdSe into ZnO was determined to be vital to suppression of interfacial recombination. However, depletion of the ZnO also restricted the effective diffusion core for electrons and slowed their transport. Thus, materials and geometries should be chosen to allow for a depletion layer that suppresses interfacial recombination without impeding electron transport to the point that it is detrimental to cell performance. Thin film solar cells are another promising technology that can reduce costs by relaxing material processing requirements. CuInxGa (1-x)Se (CIGS) is a well studied thin film solar cell material that has achieved good efficiencies of 22.6%. However, use of rare elements raise concerns over the use of CIGS for global power production. CuSbS2 shares chemistry with CuInSe2 and also presents desirable properties for thin film absorbers such as optimal band gap (1.5 eV), high absorption coefficient, and Earth-abundant and non-toxic elements. Despite the promise of CuSbS2, direct characterization of the material for solar cell application is scarce in the literature. CuSbS2 nanoplates were synthesized by a colloidal hot-injection method at 220 °C in oleylamine. The CuSbS2 platelets synthesized for 30 minutes had dimensions of 300 nm by 400 nm with a thickness of 50 nm and were capped with the insulating oleylamine synthesis ligand. The oleylamine synthesis ligand provides control over nanocrystal growth but is detrimental to intercrystal charge transport that is necessary for optoelectronic device applications. Solid-state and solution phase ligand exchange of oleylamine with S2- were used to fabricate mesoporous films of CuSbS2 nanoplates for application in solar cells. Exchange of the synthesis ligand with S2- resulted in a two order of magnitude increase in 4-point probe conductivity. Photoexcited carrier lifetimes of 1.4 ns were measured by time-resolved terahertz spectroscopy, indicating potential for CuSbS2 as a solar cell absorber material.

Processing of CuInSe{sub 2}-based solar cells: Characterization of deposition processes in terms of chemical reaction analyses. Phase 2 Annual Report, 6 May 1996--5 May 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, T.

This report describes research performed by the University of Florida during Phase 2 of this subcontract. First, to study CIGS, researchers adapted a contactless, nondestructive technique previously developed for measuring photogenerated excess carrier lifetimes in SOI wafers. This dual-beam optical modulation (DBOM) technique was used to investigate the differences between three alternative methods of depositing CdS (conventional chemical-bath deposition [CBD], metal-organic chemical vapor deposition [MOCVD], and sputtering). Second, a critical assessment of the Cu-In-Se thermochemical and phase diagram data using standard CALPHAD procedures is being performed. The outcome of this research will produce useful information on equilibrium vapor compositions (requiredmore » annealing ambients, Sex fluxes from effusion cells), phase diagrams (conditions for melt-assisted growth), chemical potentials (driving forces for diffusion and chemical reactions), and consistent solution models (extents of solid solutions and extending phase diagrams). Third, an integrated facility to fabricate CIS PV devices was established that includes migration-enhanced epitaxy (MEE) for deposition of CIS, a rapid thermal processing furnace for absorber film formation, sputtering of ZnO, CBD or MOCVD of CdS, metallization, and pattern definition.« less

Insights into cadmium diffusion mechanisms in two-stage diffusion profiles in solar-grade Cu(In,Ga)Se{sub 2} thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biderman, N. J.; Sundaramoorthy, R.; Haldar, Pradeep

Cadmium diffusion experiments were performed on polished copper indium gallium diselenide (Cu(In,Ga)Se{sub 2} or CIGS) samples with resulting cadmium diffusion profiles measured by time-of-flight secondary ion mass spectroscopy. Experiments done in the annealing temperature range between 275 °C and 425 °C reveal two-stage cadmium diffusion profiles which may be indicative of multiple diffusion mechanisms. Each stage can be described by the standard solutions of Fick's second law. The slower cadmium diffusion in the first stage can be described by the Arrhenius equation D{sub 1} = 3 × 10{sup −4} exp (− 1.53 eV/k{sub B}T) cm{sup 2} s{sup −1}, possibly representing vacancy-meditated diffusion. The faster second-stage diffusion coefficients determined in these experiments matchmore » the previously reported cadmium diffusion Arrhenius equation of D{sub 2} = 4.8 × 10{sup −4} exp (−1.04 eV/k{sub B}T) cm{sup 2} s{sup −1}, suggesting an interstitial-based mechanism.« less

Structural defects and recombination behavior of excited carriers in Cu(In,Ga)Se{sub 2} solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, J.; Du, H. W.; Li, Y.

2016-08-15

The carriers’ behavior in neutral region (NTR) and space charged region (SCR) of Cu(In,Ga)Se{sub 2} thin film based solar cells has been investigated by temperature dependent photoluminescence (PL-T), electroluminescence (EL-T) and current-voltage (IV-T) from 10 to 300 K. PL-T spectra show that three kinds of defects, namely V{sub Se}, In{sub Cu} and (In{sub Cu}+V{sub Cu}), are localized within the band gap of NTR and SCR of CIGS layer, corresponding to the energy levels of E{sub C}-0.08, E{sub C}-0.20 and E{sub C}-0.25 eV, respectively. The In{sub Cu} and (In{sub Cu}+V{sub Cu}) deep level defects are non-radiative recombination centers at room temperature.more » The IV-T and EL-T analysis reveals that the injection modes of electrons from ZnO conduction band into Cu(In,Ga)Se{sub 2} layer are tunneling, thermally-excited tunneling and thermionic emission under 10-40, 60-160, and 180-300 K, respectively. At 10-160 K, the electrons tunnel into (In{sub Cu}+V{sub Cu}) and V{sub se} defect levels in band gap of SCR and the drifting is involved in the emission bands at 0.96 and 1.07 eV, which is the direct evidence for a tunneling assisted recombination. At 180-300 K, the electrons are directly injected into the Cu(In,Ga)Se{sub 2} conduction band, and the emission of 1.13 eV are ascribed to the transitions from the conduction band to the valence band.« less

E-Cigarettes: A Review of New Trends in Cannabis Use.

PubMed

Giroud, Christian; de Cesare, Mariangela; Berthet, Aurélie; Varlet, Vincent; Concha-Lozano, Nicolas; Favrat, Bernard

2015-08-21

The emergence of electronic cigarettes (e-cigs) has given cannabis smokers a new method of inhaling cannabinoids. E-cigs differ from traditional marijuana cigarettes in several respects. First, it is assumed that vaporizing cannabinoids at lower temperatures is safer because it produces smaller amounts of toxic substances than the hot combustion of a marijuana cigarette. Recreational cannabis users can discretely "vape" deodorized cannabis extracts with minimal annoyance to the people around them and less chance of detection. There are nevertheless several drawbacks worth mentioning: although manufacturing commercial (or homemade) cannabinoid-enriched electronic liquids (e-liquids) requires lengthy, complex processing, some are readily on the Internet despite their lack of quality control, expiry date, and conditions of preservation and, above all, any toxicological and clinical assessment. Besides these safety problems, the regulatory situation surrounding e-liquids is often unclear. More simply ground cannabis flowering heads or concentrated, oily THC extracts (such as butane honey oil or BHO) can be vaped in specially designed, pen-sized marijuana vaporizers. Analysis of a commercial e-liquid rich in cannabidiol showed that it contained a smaller dose of active ingredient than advertised; testing our laboratory-made, purified BHO, however, confirmed that it could be vaped in an e-cig to deliver a psychoactive dose of THC. The health consequences specific to vaping these cannabis preparations remain largely unknown and speculative due to the absence of comprehensive, robust scientific studies. The most significant health concerns involve the vaping of cannabinoids by children and teenagers. E-cigs could provide an alternative gateway to cannabis use for young people. Furthermore, vaping cannabinoids could lead to environmental and passive contamination.

The Computational Infrastructure for Geodynamics as a Community of Practice

NASA Astrophysics Data System (ADS)

Hwang, L.; Kellogg, L. H.

2016-12-01

Computational Infrastructure for Geodynamics (CIG), geodynamics.org, originated in 2005 out of community recognition that the efforts of individual or small groups of researchers to develop scientifically-sound software is impossible to sustain, duplicates effort, and makes it difficult for scientists to adopt state-of-the art computational methods that promote new discovery. As a community of practice, participants in CIG share an interest in computational modeling in geodynamics and work together on open source software to build the capacity to support complex, extensible, scalable, interoperable, reliable, and reusable software in an effort to increase the return on investment in scientific software development and increase the quality of the resulting software. The group interacts regularly to learn from each other and better their practices formally through webinar series, workshops, and tutorials and informally through listservs and hackathons. Over the past decade, we have learned that successful scientific software development requires at a minimum: collaboration between domain-expert researchers, software developers and computational scientists; clearly identified and committed lead developer(s); well-defined scientific and computational goals that are regularly evaluated and updated; well-defined benchmarks and testing throughout development; attention throughout development to usability and extensibility; understanding and evaluation of the complexity of dependent libraries; and managed user expectations through education, training, and support. CIG's code donation standards provide the basis for recently formalized best practices in software development (geodynamics.org/cig/dev/best-practices/). Best practices include use of version control; widely used, open source software libraries; extensive test suites; portable configuration and build systems; extensive documentation internal and external to the code; and structured, human readable input formats.

ADHD symptoms impact smoking outcomes and withdrawal in response to Varenicline treatment for smoking cessation.

PubMed

Bidwell, L Cinnamon; Karoly, Hollis C; Hutchison, Kent E; Bryan, Angela D

2017-10-01

Attention-Deficit/Hyperactivity Disorder (ADHD) is associated with nicotine dependence and difficulty quitting smoking. Few cessation trials specifically consider the impact of ADHD on treatment outcomes, including those testing established pharmacological therapies, such as varenicline. The current study focused on the impact of pretreatment ADHD inattention (IN) and hyperactivity-impulsivity (HI) symptoms on treatment outcome in a randomized controlled trial of varenicline [N=205, average age=34.13(10.07), average baseline cigarettes per day=14.71(7.06)]. Given that varenicline's putative therapeutic mechanism is attenuation of withdrawal severity during abstinence, we also tested changes in withdrawal as a mediator of treatment effects in high and low ADHD groups. ADHD symptom severity in this sample was in the subclinical range. Cessation was associated with HI, but not IN, such that high HI individuals on varenicline reported the lowest smoking levels at the end of treatment across all groups (3.06cig/day for high HI vs 4.02cig/day for low HI). Individuals with high HI who received placebo had the highest smoking at the end of treatment (7.69cigs/day for high HI vs 5.56cig/day for low HI). Patterns continued at follow-up. Varenicline significantly reduced withdrawal for those with high HI, but not low HI. However, path models did not support an indirect effect of medication on reducing smoking via withdrawal in either group, suggesting that unmeasured variables are involved in varenicline's effect on reducing smoking. These data add to a gap in the smoking cessation literature regarding the impact of ADHD symptoms on the efficacy and mechanisms of frontline pharmacological treatments. Copyright © 2017 Elsevier B.V. All rights reserved.

E-Cigarettes: A Review of New Trends in Cannabis Use

PubMed Central

Giroud, Christian; de Cesare, Mariangela; Berthet, Aurélie; Varlet, Vincent; Concha-Lozano, Nicolas; Favrat, Bernard

2015-01-01

The emergence of electronic cigarettes (e-cigs) has given cannabis smokers a new method of inhaling cannabinoids. E-cigs differ from traditional marijuana cigarettes in several respects. First, it is assumed that vaporizing cannabinoids at lower temperatures is safer because it produces smaller amounts of toxic substances than the hot combustion of a marijuana cigarette. Recreational cannabis users can discretely “vape” deodorized cannabis extracts with minimal annoyance to the people around them and less chance of detection. There are nevertheless several drawbacks worth mentioning: although manufacturing commercial (or homemade) cannabinoid-enriched electronic liquids (e-liquids) requires lengthy, complex processing, some are readily on the Internet despite their lack of quality control, expiry date, and conditions of preservation and, above all, any toxicological and clinical assessment. Besides these safety problems, the regulatory situation surrounding e-liquids is often unclear. More simply ground cannabis flowering heads or concentrated, oily THC extracts (such as butane honey oil or BHO) can be vaped in specially designed, pen-sized marijuana vaporizers. Analysis of a commercial e-liquid rich in cannabidiol showed that it contained a smaller dose of active ingredient than advertised; testing our laboratory-made, purified BHO, however, confirmed that it could be vaped in an e-cig to deliver a psychoactive dose of THC. The health consequences specific to vaping these cannabis preparations remain largely unknown and speculative due to the absence of comprehensive, robust scientific studies. The most significant health concerns involve the vaping of cannabinoids by children and teenagers. E-cigs could provide an alternative gateway to cannabis use for young people. Furthermore, vaping cannabinoids could lead to environmental and passive contamination. PMID:26308021

Pilot Task Profiles, Human Factors, And Image Realism

NASA Astrophysics Data System (ADS)

McCormick, Dennis

1982-06-01

Computer Image Generation (CIG) visual systems provide real time scenes for state-of-the-art flight training simulators. The visual system reauires a greater understanding of training tasks, human factors, and the concept of image realism to produce an effective and efficient training scene than is required by other types of visual systems. Image realism must be defined in terms of pilot visual information reauirements. Human factors analysis of training and perception is necessary to determine the pilot's information requirements. System analysis then determines how the CIG and display device can best provide essential information to the pilot. This analysis procedure ensures optimum training effectiveness and system performance.

Second-hand smoke exposure generated by new electronic devices (IQOS® and e-cigs) and traditional cigarettes: submicron particle behaviour in human respiratory system.

PubMed

Protano, C; Manigrasso, M; Avino, P; Sernia, S; Vitali, M

2016-01-01

Passive exposure profiles to submicronic particles (SMPs, 5.6-560 nm) of traditional cigarettes and new electronic commercial devices (e-cig and IQOS®, a new heat-not-burn smoking device) were compared. During smoking, SMPs released by traditional cigarettes resulted four-times higher than those released by electronic and heat-not-burn devices and remained high for at least one hour, while SMPs values returned immediately similar to background for electronic and heat-not-burn devices. In all experiments, approximately half of SMPs resulted so small to reach the alveolar region.

Effectiveness of adjunctive antimicrobial photodynamic therapy in reducing peri-implant inflammatory response in individuals vaping electronic cigarettes: A randomized controlled clinical trial.

PubMed

Al Rifaiy, Mohammed Q; Qutub, Osama A; Alasqah, Mohammed N; Al-Sowygh, Zeyad H; Mokeem, Sameer A; Alrahlah, Ali

2018-06-01

There are no studies that have assessed the effectiveness of antimicrobial photodynamic therapy (aPDT) in reducing peri-implant inflammatory response in individuals vaping electronic cigarettes (e-cigs). This study explored the effectiveness of aPDT as an adjunct to mechanical debridement (MD) in the treatment of peri-implant mucositis (p-iM) in individuals vaping e-cigs. Vaping individuals with p-iM were divided into 2 groups: (a) Group-I: receiving MD with aPDT (test group); and (b) Group-II: MD only (control group). Peri-implant inflammatory parameters including plaque index (PI), bleeding on probing (BoP), and pocket depth (PD) were assessed at baseline and 12-weeks follow-up. Inter- and intra-group comparisons were made using Mann-Whitney U test and Wilcoxon signed ranks test. P-value < 0.05 was considered significant. Thirty-eight male patients (20 in Group-I and 18 in Group-II) were included. The mean age of vaping individuals in groups I and II were 33.6 ± 2.8 and 35.4 ± 2.1 years, respectively. Mean daily frequency of vaping e-cigs in groups I and II was 7.3 ± 0.9 and 5.9 ± 1.0 whereas mean duration of vaping e-cigs was 4.8 ± 1.5 and 4.1 ± 1.3 years respectively. There was no significant difference between groups at baseline. There was significant improvement in PI (p < 0.001) and PD (p < 0.001) at 12-weeks follow-up with respect to the baseline visit in both groups. There was a significant reduction in PI (p < 0.001) and PD (p < 0.001) for group-I as compared to group-II at follow-up. There was no statistically significant difference for BoP between groups at follow-up. Antimicrobial PDT is more effective compared to MD alone in the treatment of p-iM in individuals vaping e-cigs. The findings of the present study should be considered preliminary and interpreted with caution. Further randomized clinical trials should be performed in order to obtain strong conclusions. Copyright © 2018 Elsevier B.V. All rights reserved.

Novel Film Formation Pathways for Copper Zinc Tin Selenide for Solar Cell Applications

NASA Astrophysics Data System (ADS)

Bendapudi, Sree Satya Kanth

Because of the anticipated high demand for Indium, ongoing growth of CIGS technology may be limited. Kesterite materials, which replace In with a Zn/Sn couple, are thought to be a solution to this issue. However, efficiencies are still below the 10% level, and these materials are proving to be complex. Even determination of the bandgap is not settled because of the occurrence of secondary phases. We use a film growth process, 2SSS, which we believe helps control the formation of secondary phases. Under the right growth conditions we find 1/1 Zn/Sn ratios and XRD signatures for Cu2ZnSnSe 4 with no evidence of secondary phases. The optical absorption profile of our films is also a good match to the CIS profile even for films annealed at 500°C. We see no evidence of phase separation. The effect of intentional variation of the Zn/Sn ratio on material and device properties is also presented.

Influence of sputtering deposition parameters on electrical and optical properties of aluminium-doped zinc oxide thin films for photovoltaic applications

NASA Astrophysics Data System (ADS)

Krawczak, Ewelina; Agata, Zdyb; Gulkowski, Slawomir; Fave, Alain; Fourmond, Erwann

2017-11-01

Transparent Conductive Oxides (TCOs) characterized by high visible transmittance and low electrical resistivity play an important role in photovoltaic technology. Aluminum doped zinc oxide (AZO) is one of the TCOs that can find its application in thin film solar cells (CIGS or CdTe PV technology) as well as in other microelectronic applications. In this paper some optical and electrical properties of ZnO:Al thin films deposited by RF magnetron sputtering method have been investigated. AZO layers have been deposited on the soda lime glass substrates with use of variable technological parameters such as pressure in the deposition chamber, power applied and temperature during the process. The composition of AZO films has been investigated by EDS method. Thickness and refraction index of the deposited layers in dependence on certain technological parameters of sputtering process have been determined by spectroscopic ellipsometry. The measurements of transmittance and sheet resistance were also performed.

Nanotechnologies for efficient solar and wind energy harvesting and storage

NASA Astrophysics Data System (ADS)

Eldada, Louay A.

2010-08-01

We describe nanotechnologies used to improve the efficient harvest of energy from the Sun and the wind, and the efficient storage of energy in secondary batteries and ultracapacitors, for use in a variety of applications including smart grids, electric vehicles, and portable electronics. We demonstrate high-quality nanostructured copper indium gallium selenide (CIGS) thin films for photovoltaic (PV) applications. The self-assembly of nanoscale p-n junction networks creates n-type networks that act as preferential electron pathways, and p-type networks that act as preferential hole pathways, allowing positive and negative charges to travel to the contacts in physically separated paths, reducing charge recombination. We also describe PV nanotechnologies used to enhance light trapping, photon absorption, charge generation, charge transport, and current collection. Furthermore, we describe nanotechnologies used to improve the efficiency of power-generating wind turbines. These technologies include nanoparticle-containing lubricants that reduce the friction generated from the rotation of the turbines, nanocoatings for de-icing and self-cleaning technologies, and advanced nanocomposites that provide lighter and stronger wind blades. Finally, we describe nanotechnologies used in advanced secondary batteries and ultracapacitors. Nanostructured powder-based and carbon-nanotube-based cathodes and anodes with ultra-high surface areas boost the energy and power densities in secondary batteries, including lithium-ion and sodium-sulfur batteries. Nanostructured carbon materials are also controlled on a molecular level to offer large surface areas for the electrodes of ultracapacitors, allowing to store and supply large bursts of energy needed in some applications.

Evolution of opto-electronic properties during film formation of complex semiconductors

NASA Astrophysics Data System (ADS)

Heinemann, M. D.; Mainz, R.; Österle, F.; Rodriguez-Alvarez, H.; Greiner, D.; Kaufmann, C. A.; Unold, T.

2017-04-01

Optical and electrical properties of complex semiconducting alloys like Cu(In,Ga)Se2 (CIGS) are strongly influenced by the reaction pathways occurring during their deposition process. This makes it desirable to observe and control these properties in real-time during the deposition. Here we show for the first time the evolution of the band gap and the sub-band-gap defect absorption of CIGS thin film as well as surface roughness during a three-stage co-evaporation process by means of an optical analysis technique, based on white light reflectometry (WLR). By simultaneously recording structural information with in-situ energy dispersive X-ray diffraction and X-ray fluorescence we can directly correlate the evolution of opto-electronic material parameters with the structural properties of the film during growth. We find that the surface roughness and the sub-gap light absorption can be correlated with the phase evolution during the transformation from (In,Ga)2Se3 to Cu(In,Ga)Se2 by the incorporation of Cu into the film. Sub-bandgap light absorption is found to be influenced by the Cu-saturated growth phase and is lowered close to the points of stoichiometry, allowing for an advanced process design.

Assessing Reliability of Cold Spray Sputter Targets in Photovoltaic Manufacturing

NASA Astrophysics Data System (ADS)

Hardikar, Kedar; Vlcek, Johannes; Bheemreddy, Venkata; Juliano, Daniel

2017-10-01

Cold spray has been used to manufacture more than 800 Cu-In-Ga (CIG) sputter targets for deposition of high-efficiency photovoltaic thin films. It is a preferred technique since it enables high deposit purity and transfer of non-equilibrium alloy states to the target material. In this work, an integrated approach to reliability assessment of such targets with deposit weight in excess of 50 lb. is undertaken, involving thermal-mechanical characterization of the material in as-deposited condition, characterization of the interface adhesion on cylindrical substrate in as-deposited condition, and developing means to assess target integrity under thermal-mechanical loads during the physical vapor deposition (PVD) sputtering process. Mechanical characterization of cold spray deposited CIG alloy is accomplished through the use of indentation testing and adaptation of Brazilian disk test. A custom lever test was developed to characterize adhesion along the cylindrical interface between the CIG deposit and cylindrical substrate, overcoming limitations of current standards. A cohesive zone model for crack initiation and propagation at the deposit interface is developed and validated using the lever test and later used to simulate the potential catastrophic target failure in the PVD process. It is shown that this approach enables reliability assessment of sputter targets and improves robustness.

First principles based multiparadigm modeling of electronic structures and dynamics

NASA Astrophysics Data System (ADS)

Xiao, Hai

Electronic structures and dynamics are the key to linking the material composition and structure to functionality and performance. An essential issue in developing semiconductor devices for photovoltaics is to design materials with optimal band gaps and relative positioning of band levels. Approximate DFT methods have been justified to predict band gaps from KS/GKS eigenvalues, but the accuracy is decisively dependent on the choice of XC functionals. We show here for CuInSe2 and CuGaSe2, the parent compounds of the promising CIGS solar cells, conventional LDA and GGA obtain gaps of 0.0-0.01 and 0.02-0.24 eV (versus experimental values of 1.04 and 1.67 eV), while the historically first global hybrid functional, B3PW91, is surprisingly the best, with band gaps of 1.07 and 1.58 eV. Furthermore, we show that for 27 related binary and ternary semiconductors, B3PW91 predicts gaps with a MAD of only 0.09 eV, which is substantially better than all modern hybrid functionals, including B3LYP (MAD of 0.19 eV) and screened hybrid functional HSE06 (MAD of 0.18 eV). The laboratory performance of CIGS solar cells (> 20% efficiency) makes them promising candidate photovoltaic devices. However, there remains little understanding of how defects at the CIGS/CdS interface affect the band offsets and interfacial energies, and hence the performance of manufactured devices. To determine these relationships, we use the B3PW91 hybrid functional of DFT with the AEP method that we validate to provide very accurate descriptions of both band gaps and band offsets. This confirms the weak dependence of band offsets on surface orientation observed experimentally. We predict that the CBO of perfect CuInSe2/CdS interface is large, 0.79 eV, which would dramatically degrade performance. Moreover we show that band gap widening induced by Ga adjusts only the VBO, and we find that Cd impurities do not significantly affect the CBO. Thus we show that Cu vacancies at the interface play the key role in enabling the tunability of CBO. We predict that Na further improves the CBO through electrostatically elevating the valence levels to decrease the CBO, explaining the observed essential role of Na for high performance. Moreover we find that K leads to a dramatic decrease in the CBO to 0.05 eV, much better than Na. We suggest that the efficiency of CIGS devices might be improved substantially by tuning the ratio of Na to K, with the improved phase stability of Na balancing phase instability from K. All these defects reduce interfacial stability slightly, but not significantly. A number of exotic structures have been formed through high pressure chemistry, but applications have been hindered by difficulties in recovering the high pressure phase to ambient conditions (i.e., one atmosphere and room temperature). Here we use dispersion-corrected DFT (PBE-ulg flavor) to predict that above 60 GPa the most stable form of N2O (the laughing gas in its molecular form) is a 1D polymer with an all-nitrogen backbone analogous to cis-polyacetylene in which alternate N are bonded (ionic covalent) to O. The analogous trans-polymer is only 0.03-0.10 eV/molecular unit less stable. Upon relaxation to ambient conditions both polymers relax below 14 GPa to the same stable non-planar trans-polymer, accompanied by possible electronic structure transitions. The predicted phonon spectrum and dissociation kinetics validate the stability of this trans-poly-NNO at ambient conditions, which has potential applications as a new type of conducting polymer with all-nitrogen chains and as a high-energy oxidizer for rocket propulsion. This work illustrates in silico materials discovery particularly in the realm of extreme conditions. Modeling non-adiabatic electron dynamics has been a long-standing challenge for computational chemistry and materials science, and the eFF method presents a cost-efficient alternative. However, due to the deficiency of FSG representation, eFF is limited to low-Z elements with electrons of predominant s-character. To overcome this, we introduce a formal set of ECP extensions that enable accurate description of p-block elements. The extensions consist of a model representing the core electrons with the nucleus as a single pseudo particle represented by FSG, interacting with valence electrons through ECPs. We demonstrate and validate the ECP extensions for complex bonding structures, geometries, and energetics of systems with p-block character (C, O, Al, Si) and apply them to study materials under extreme mechanical loading conditions. Despite its success, the eFF framework has some limitations, originated from both the design of Pauli potentials and the FSG representation. To overcome these, we develop a new framework of two-level hierarchy that is a more rigorous and accurate successor to the eFF method. (Abstract shortened by UMI.).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horowitz, Kelsey A. W.; Fu, Ran; Woodhouse, Michael

This article examines current cost drivers and potential avenues to reduced cost for monolithic, glass-glass Cu(In,Ga)(Se,S)2 (CIGS) modules by constructing a comprehensive bottom-up cost model. For a reference case where sputtering plus batch sulfurization after selenization (SAS) is employed, we compute a manufacturing cost of $69/m2 if the modules are made in the United States at a 1 GW/year production volume. At 14% module efficiency, this corresponds to a manufacturing cost of $0.49/WDC and a minimum sustainable price (MSP) of $0.67/WDC. We estimate that MSP could vary within +/-20% of this value given the range of quoted input prices, andmore » existing variations in module design, manufacturing processes, and manufacturing location. Potential for reduction in manufacturing costs to below $0.40/WDC may be possible if average production module efficiencies can be increased above 17% without increasing $/m2 costs; even lower costs could be achieved if $/m2 costs could be reduced, particularly via innovations in the CIGS deposition process or balance-of-module elements. We present the impact on cost of regional factors, CIGS deposition method, device design, and price fluctuations. One metric of competitiveness-levelized cost of energy (LCOE) -- is also assessed for several U.S. locations and compared to that of standard multi-crystalline silicon (m(c-Si)) and cadmium telluride (CdTe).« less

Smoking status is inversely associated with overall diet quality: Findings from the ORISCAV-LUX study.

PubMed

Alkerwi, Ala'a; Baydarlioglu, Burcu; Sauvageot, Nicolas; Stranges, Saverio; Lemmens, Paul; Shivappa, Nitin; Hébert, James R

2017-10-01

Relationships between food consumption/nutrient intake and tobacco smoking have been described in the literature. However, little is known about the association between smoking and overall diet quality. This study examined the associations between eight diet quality indices, namely, the Diet Quality Index-International (DQI-I), Recommendation Compliance Index (RCI), Dietary Approach to Stop Hypertension (DASH) score, Energy Density Score (EDS), Dietary Diversity Score (DDS), Recommended Food Score (RFS), non-Recommended Food Score (non-RFS), and Dietary Inflammatory Index (DII), and smoking status with a focus on smoking intensity. Analyses were based on a sample of 1352 participants in the Observation of Cardiovascular Risk Factors in Luxembourg (ORISCAV-LUX) survey, a nationwide population-based cross-sectional study of adults aged 18-69 years. Nutritional data from food frequency questionnaire (FFQ) were used to compute selected diet quality indices. Participants were classified as never smoker, former smoker (≥12 months cessation period), occasional or light smokers (≤1 cig/d), moderate smokers (≤20 cig/d) and heavy smokers (>20 cig/d). Descriptive and linear regression analyses were performed, after adjustment for several potential covariates. Compared to the other groups, heavy smokers had significantly higher prevalence of dyslipidemia (83%), obesity (34%), and elevated glycemic biomarkers. About 50% of former smokers had hypertension. Diet quality of heavy smokers was significantly poorer than those who never smoked independent of several socioeconomic, lifestyle, and biologic confounding factors (all p < 0.001). Heavy smokers were less compliant with national or international dietary recommendations, expressed by RCI, DQI-I, and RFS. In addition, they consumed a more pro-inflammatory diet, as expressed by higher DII scores (P < 0.001) and self-reported less dietary diversity in their food choices, as expressed by DDS. This study provides new evidence concerning an inverse relationship between the intensity of tobacco consumption and overall diet quality. The implication is that efforts aimed at tobacco control should target heavy smokers and intervention on smoking cessation should take into account diet quality of smokers and their nutritional habits, to increase effectiveness and relevance of public health messages. Copyright © 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

SISGR: Defect Studies of CZTSSe & Related Thin Film Photovoltaic Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scarpulla, Michael

2017-03-30

The research objectives of this project centered around investigations of the basic properties of Cu2ZnSn(S,Se)4 especially the electronic defects in the bulk, at the interface with heterojunction partners used in solar cells, and at the polycrystalline grain boundaries. In the course of the project we addressed many specific sub-areas in 17 peer reviewed publications listed at the end of this report (2 more are also in preparation). The impact of this research is to generate basic but critical materials knowledge about this emerging alloy system that may be capable of photovoltaic efficiency on par with CdTe and CIGS but atmore » lower cost and having the benefit of avoiding constraints on scale-up from rare and expensive elements using earth abundant elements. In the final phase of this project, Prof. Scarpulla worked with Dr. Kirstin Alberi at NREL and rigorously solved a theoretical problem that is general across all semiconductors – the prediction of point defect concentrations in the presence of excess carriers.« less

Space Plasma Testing of High-Voltage Thin-Film Solar Arrays with Protective Coatings

NASA Technical Reports Server (NTRS)

Tlomak, Pawel; Hausgen, Paul E.; Merrill, John; Senft, Donna; Piszczor, Michael F., Jr.

2007-01-01

This paper gives an overview of the space plasma test program for thin-film photovoltaics (TFPV) technologies developed at the Air Force Research Laboratory (AFRL). The main objective of this program is to simulate the effects of space plasma characteristic of LEO and MEO environments on TFPV. Two types of TFPV, amorphous silicon (a-Si) and copper-indium-gallium-diselenide (CIGS), coated with two types of thin-film, multifunctional coatings were used for these studies. This paper reports the results of the first phase of this program, namely the results of preliminary electrostatic charging, arcing, dielectric breakdown, and collection current measurements carried out with a series of TFPV exposed to simulated space plasma at the NASA Glenn Plasma Interaction Facility. The experimental data demonstrate that multifunctional coatings developed for this program provide effective protection against the plasma environment while minimizing impact on power generation performance. This effort is part of an ongoing program led by the Space Vehicles Directorate at the AFRL devoted to the development and space qualification of TFPV and their protective coatings.

Grain-boundary physics in polycrystalline CuInSe2 revisited: experiment and theory.

PubMed

Yan, Yanfa; Noufi, R; Al-Jassim, M M

2006-05-26

Current studies have attributed the remarkable performance of polycrystalline CuInSe2 (CIS) to anomalous grain-boundary (GB) physics in CIS. The recent theory predicts that GBs in CIS are hole barriers, which prevent GB electrons from recombining. We examine the atomic structure and chemical composition of (112) GBs in Cu(In,Ga)Se2 (CIGS) using high-resolution Z-contrast imaging and nanoprobe x-ray energy-dispersive spectroscopy. We show that the theoretically predicted Cu-vacancy rows are not observed in (112) GBs in CIGS. Our first-principles modeling further reveals that the (112) GBs in CIS do not act as hole barriers. Our results suggest that the superior performance of polycrystalline CIS should not be explained solely by the GB behaviors.

Colloidal Nanocrystals with Near-infrared Optical Properties: Synthesis, Characterization, and Applications

NASA Astrophysics Data System (ADS)

Panthani, Matthew George

2011-07-01

Colloidal nanocrystals with optical properties in the near-infrared (NIR) are of interest for many applications such as photovoltaic (PV) energy conversion, bioimaging, and therapeutics. For PVs and other electronic devices, challenges in using colloidal nanomaterials often deal with the surfaces. Because of the high surface-to-volume ratio of small nanocrystals, surfaces and interfaces play an enhanced role in the properties of nanocrystal films and devices. Organic ligand-capped CuInSe2 (CIS) and Cu(InXGa 1-X)Se2 (CIGS) nanocrystals were synthesized and used as the absorber layer in prototype solar cells. By fabricating devices from spray-coated CuInSe nanocrystals under ambient conditions, solar-to-electric power conversion efficiencies as high as 3.1% were achieved. Many treatments of the nanocrystal films were explored. Although some treatments increased the conductivity of the nanocrystal films, the best devices were from untreated CIS films. By modifying the reaction chemistry, quantum-confined CuInSe XS2-X (CISS) nanocrystals were produced. The potential of the CISS nanocrystals for targeted bioimaging was demonstrated via oral delivery to mice and imaging of nanocrystal fluorescence. The size-dependent photoluminescence of Si nanocrystals was measured. Si nanocrystals supported on graphene were characterized by conventional transmission electron microscopy and spherical aberration (Cs)-corrected scanning transmission electron microscopy (STEM). Enhanced imaging contrast and resolution was achieved by using Cs-corrected STEM with a graphene support. In addition, clear imaging of defects and the organic-inorganic interface was enabled by utilizing this technique.

Development of betavoltaic cell technology production based on microchannel silicon and its electrical parameters evaluation.

PubMed

Krasnov, A A; Starkov, V V; Legotin, S A; Rabinovich, O I; Didenko, S I; Murashev, V N; Cheverikin, V V; Yakimov, E B; Fedulova, N A; Rogozev, B I; Laryushkin, A S

2017-03-01

In the paper a manufacturing process of three-dimensional (3D) microchannel structure by silicon (Si) anodic etching was discussed. The possibility of microchannels formation allows to increase the active area more than 100 times. In this structure the p-n junction on the whole Si surface was formed. The obtained data allowed to evaluate the characteristics of the betavoltaic converter with a 3D structure by using isotope 63Ni with a specific activity of 10Ci/g. Copyright © 2016 Elsevier Ltd. All rights reserved.

Vapors Produced by Electronic Cigarettes and E-Juices with Flavorings Induce Toxicity, Oxidative Stress, and Inflammatory Response in Lung Epithelial Cells and in Mouse Lung

PubMed Central

Lerner, Chad A.; Sundar, Isaac K.; Yao, Hongwei; Gerloff, Janice; Ossip, Deborah J.; McIntosh, Scott; Robinson, Risa; Rahman, Irfan

2015-01-01

Oxidative stress and inflammatory response are the key events in the pathogenesis of chronic airway diseases. The consumption of electronic cigarettes (e-cigs) with a variety of e-liquids/e-juices is alarmingly increasing without the unrealized potential harmful health effects. We hypothesized that electronic nicotine delivery systems (ENDS)/e-cigs pose health concerns due to oxidative toxicity and inflammatory response in lung cells exposed to their aerosols. The aerosols produced by vaporizing ENDS e-liquids exhibit oxidant reactivity suggesting oxidants or reactive oxygen species (OX/ROS) may be inhaled directly into the lung during a “vaping” session. These OX/ROS are generated through activation of the heating element which is affected by heating element status (new versus used), and occurs during the process of e-liquid vaporization. Unvaporized e-liquids were oxidative in a manner dependent on flavor additives, while flavors containing sweet or fruit flavors were stronger oxidizers than tobacco flavors. In light of OX/ROS generated in ENDS e-liquids and aerosols, the effects of ENDS aerosols on tissues and cells of the lung were measured. Exposure of human airway epithelial cells (H292) in an air-liquid interface to ENDS aerosols from a popular device resulted in increased secretion of inflammatory cytokines, such as IL-6 and IL-8. Furthermore, human lung fibroblasts exhibited stress and morphological change in response to treatment with ENDS/e-liquids. These cells also secrete increased IL-8 in response to a cinnamon flavored e-liquid and are susceptible to loss of cell viability by ENDS e-liquids. Finally, exposure of wild type C57BL/6J mice to aerosols produced from a popular e-cig increase pro-inflammatory cytokines and diminished lung glutathione levels which are critical in maintaining cellular redox balance. Thus, exposure to e-cig aerosols/juices incurs measurable oxidative and inflammatory responses in lung cells and tissues that could lead to unrealized health consequences. PMID:25658421

A C. elegans model of electronic cigarette use: Physiological effects of e-liquids in nematodes.

PubMed

Panitz, Daniel; Swamy, Harsha; Nehrke, Keith

2015-12-04

Electronic cigarettes (e-cigs) have recently become very popular particularly among the younger generation. These nicotine delivery devices are viewed as a preferable alternative to more conventional forms of tobacco use and are thought to reduce the risk of chronic obstructive pulmonary disease, the third leading cause of death worldwide. However, there is very little data available on the consequences of e-cig use, though recently nicotine-independent inflammatory responses have been reported. The genetic model organism Caenorhabditis elegans is a soil nematode whose cell biology is remarkably well conserved with mammals. Here, we used C. elegans to test the physiologic effects of e-liquids used to refill e-cigs. Larval worms were exposed from hatching onwards to low concentrations (0.2 %) of e-liquids, distilled e-liquid vapor, propylene glycol (PG), or M9 buffer as a negative control. E-liquids tested included grape, menthol, and V2 Red "classic tobacco" flavors. Nicotine (48 ppm) was tested as a second level variable. Stereotypical physiological outputs were then measured, including developmental rate, fecundity, locomotion, lifespan, and the induction of canonical stress signaling pathways. A small but significant impairment of developmental rate and brood size was observed for PG and V2 Red treated worms compared to the negative control. Worms treated with e-liquids containing nicotine fared significantly worse than those that did not, but vaporization did not increase toxicity. Finally, both PG and V2 Red e-liquid induced an oxidative stress response in the absence of nicotine. PG exposure is sufficient to induce an oxidative stress response in nematodes, while nicotine is not. Both PG and nicotine independently influence physiologic measures of health and viability. The e-liquid flavorings did not significantly impact outcomes and there was no evidence for vaporization altering toxicity. These data suggest that the major physiologically significant component of e-liquids besides nicotine is likely the common solvent PG. We conclude that C. elegans are an appropriate model to rapidly assess parameters that may contribute to the basic cell biological effects of e-cigs.

Computational Infrastructure for Geodynamics (CIG)

NASA Astrophysics Data System (ADS)

Gurnis, M.; Kellogg, L. H.; Bloxham, J.; Hager, B. H.; Spiegelman, M.; Willett, S.; Wysession, M. E.; Aivazis, M.

2004-12-01

Solid earth geophysicists have a long tradition of writing scientific software to address a wide range of problems. In particular, computer simulations came into wide use in geophysics during the decade after the plate tectonic revolution. Solution schemes and numerical algorithms that developed in other areas of science, most notably engineering, fluid mechanics, and physics, were adapted with considerable success to geophysics. This software has largely been the product of individual efforts and although this approach has proven successful, its strength for solving problems of interest is now starting to show its limitations as we try to share codes and algorithms or when we want to recombine codes in novel ways to produce new science. With funding from the NSF, the US community has embarked on a Computational Infrastructure for Geodynamics (CIG) that will develop, support, and disseminate community-accessible software for the greater geodynamics community from model developers to end-users. The software is being developed for problems involving mantle and core dynamics, crustal and earthquake dynamics, magma migration, seismology, and other related topics. With a high level of community participation, CIG is leveraging state-of-the-art scientific computing into a suite of open-source tools and codes. The infrastructure that we are now starting to develop will consist of: (a) a coordinated effort to develop reusable, well-documented and open-source geodynamics software; (b) the basic building blocks - an infrastructure layer - of software by which state-of-the-art modeling codes can be quickly assembled; (c) extension of existing software frameworks to interlink multiple codes and data through a superstructure layer; (d) strategic partnerships with the larger world of computational science and geoinformatics; and (e) specialized training and workshops for both the geodynamics and broader Earth science communities. The CIG initiative has already started to leverage and develop long-term strategic partnerships with open source development efforts within the larger thrusts of scientific computing and geoinformatics. These strategic partnerships are essential as the frontier has moved into multi-scale and multi-physics problems in which many investigators now want to use simulation software for data interpretation, data assimilation, and hypothesis testing.

EffiCiency and Safety of an eLectronic cigAreTte (ECLAT) as tobacco cigarettes substitute: a prospective 12-month randomized control design study.

PubMed

Caponnetto, Pasquale; Campagna, Davide; Cibella, Fabio; Morjaria, Jaymin B; Caruso, Massimo; Russo, Cristina; Polosa, Riccardo

2013-01-01

Electronic cigarettes (e-cigarettes) are becoming increasingly popular with smokers worldwide. Users report buying them to help quit smoking, to reduce cigarette consumption, to relieve tobacco withdrawal symptoms, and to continue having a 'smoking' experience, but with reduced health risks. Research on e-cigarettes is urgently needed in order to ensure that the decisions of regulators, healthcare providers and consumers are based on science. Methods ECLAT is a prospective 12-month randomized, controlled trial that evaluates smoking reduction/abstinence in 300 smokers not intending to quit experimenting two different nicotine strengths of a popular e-cigarette model ('Categoria'; Arbi Group Srl, Italy) compared to its non-nicotine choice. GroupA (n = 100) received 7.2 mg nicotine cartridges for 12 weeks; GroupB (n = 100), a 6-week 7.2 mg nicotine cartridges followed by a further 6-week 5.4 mg nicotine cartridges; GroupC (n = 100) received no-nicotine cartridges for 12 weeks. The study consisted of nine visits during which cig/day use and exhaled carbon monoxide (eCO) levels were measured. Smoking reduction and abstinence rates were calculated. Adverse events and product preferences were also reviewed. Declines in cig/day use and eCO levels were observed at each study visits in all three study groups (p<0.001 vs baseline), with no consistent differences among study groups. Smoking reduction was documented in 22.3% and 10.3% at week-12 and week-52 respectively. Complete abstinence from tobacco smoking was documented in 10.7% and 8.7% at week-12 and week-52 respectively. A substantial decrease in adverse events from baseline was observed and withdrawal symptoms were infrequently reported during the study. Participants' perception and acceptance of the product under investigation was satisfactory. In smokers not intending to quit, the use of e-cigarettes, with or without nicotine, decreased cigarette consumption and elicited enduring tobacco abstinence without causing significant side effects. ClinicalTrials.gov NCT01164072 NCT01164072.

The SOS Chromotest applied for screening plant antigenotoxic agents against ultraviolet radiation.

PubMed

Fuentes, J L; García Forero, A; Quintero Ruiz, N; Prada Medina, C A; Rey Castellanos, N; Franco Niño, D A; Contreras García, D A; Córdoba Campo, Y; Stashenko, E E

2017-09-13

In this work, we investigated the usefulness of the SOS Chromotest for screening plant antigenotoxic agents against ultraviolet radiation (UV). Fifty Colombian plant extracts obtained by supercritical fluid (CO 2 ) extraction, twelve plant extract constituents (apigenin, carvacrol, β-caryophyllene, 1,8-cineole, citral, p-cymene, geraniol, naringenin, pinocembrin, quercetin, squalene, and thymol) and five standard antioxidant and/or photoprotective agents (curcumin, epigallocatechin gallate, resveratrol, α-tocopherol, and Trolox®) were evaluated for their genotoxicity and antigenotoxicity against UV using the SOS Chromotest. None of the plant extracts, constituents or agents were genotoxic in the SOS Chromotest at tested concentrations. Based on the minimal extract concentration that significantly inhibited UV-genotoxicity (CIG), five plant extracts were antigenotoxic against UV as follows: Baccharis nítida (16 μg mL -1 ) = Solanum crotonifolium (16 μg mL -1 ) > Hyptis suaveolens (31 μg mL -1 ) = Persea caerulea (31 μg mL -1 ) > Lippia origanoides (62 μg mL -1 ). Based on CIG values, the flavonoid compounds showed the highest antigenotoxic potential as follows: apigenin (7 μM) > pinocembrin (15 μM) > quercetin (26 μM) > naringenin (38 μM) > epigallocatechin gallate (108 μM) > resveratrol (642 μM). UV-genotoxicity inhibition with epigallocatechin gallate, naringenin and resveratrol was related to its capability for inhibiting protein synthesis. A correlation analysis between compound antigenotoxicity estimates and antioxidant activity evaluated by the oxygen radical absorbance capacity (ORAC) assay showed that these activities were not related. The usefulness of the SOS Chromotest for bioprospecting of plant antigenotoxic agents against UV was discussed.

Spontaneous and strong multi-layer graphene n-doping on soda-lime glass and its application in graphene-semiconductor junctions

DOE PAGES

Dissanayake, D. M. N. M.; Ashraf, A.; Dwyer, D.; ...

2016-02-12

Scalable and low-cost doping of graphene could improve technologies in a wide range of fields such as microelectronics, optoelectronics, and energy storage. While achieving strong p-doping is relatively straightforward, non-electrostatic approaches to n-dope graphene, such as chemical doping, have yielded electron densities of 9.5 × 10 12 e/cm 2 or below. Furthermore, chemical doping is susceptible to degradation and can adversely affect intrinsic graphene’s properties. Here we demonstrate strong (1.33 × 10 13 e/cm 2), robust, and spontaneous graphene n-doping on a soda-lime-glass substrate via surface-transfer doping from Na without any external chemical, high-temperature, or vacuum processes. Remarkably, the n-dopingmore » reaches 2.11 × 10 13 e/cm 2 when graphene is transferred onto a p-type copper indium gallium diselenide (CIGS) semiconductor that itself has been deposited onto soda-lime-glass, via surface-transfer doping from Na atoms that diffuse to the CIGS surface. Using this effect, we demonstrate an n-graphene/p-semiconductor Schottky junction with ideality factor of 1.21 and strong photo-response. As a result, the ability to achieve strong and persistent graphene n-doping on low-cost, industry-standard materials paves the way toward an entirely new class of graphene-based devices such as photodetectors, photovoltaics, sensors, batteries, and supercapacitors.« less

R&D 100 Awards | NREL

Science.gov Websites

a cost of about $.50/watt. Learn more HP Apollo 8000 System HP Apollo 8000 System Uses component Award - HP Apollo 8000 System - Steve Hammond and Team 2008 Editor's Choice Award - Hybrid CIGS (copper

How to create more supportive supervision for primary healthcare: lessons from Ngamiland district of Botswana: co-operative inquiry group.

PubMed

Nkomazana, Oathokwa; Mash, Robert; Wojczewski, Silvia; Kutalek, Ruth; Phaladze, Nthabiseng

2016-01-01

Supportive supervision is a way to foster performance, productivity, motivation, and retention of health workforce. Nevertheless there is a dearth of evidence of the impact and acceptability of supportive supervision in low- and middle-income countries. This article describes a participatory process of transforming the supervisory practice of district health managers to create a supportive environment for primary healthcare workers. The objective of the study was to explore how district health managers can change their practice to create a more supportive environment for primary healthcare providers. A facilitated co-operative inquiry group (CIG) was formed with Ngamiland health district managers. CIG belongs to the participatory action research paradigm and is characterised by a cyclic process of observation, reflection, planning, and action. The CIG went through three cycles between March 2013 and March 2014. Twelve district health managers participated in the inquiry group. The major insights and learning that emerged from the inquiry process included inadequate supervisory practice, perceptions of healthcare workers' experiences, change in the managers' supervision paradigm, recognition of the supervisors' inadequate supervisory skills, and barriers to supportive supervision. Finally, the group developed a 10-point consensus on what they had learnt regarding supportive supervision. Ngamiland health district managers have come to appreciate the value of supportive supervision and changed their management style to be more supportive of their subordinates. They also developed a consensus on supportive supervision that could be adapted for use nationally. Supportive supervision should be prioritised at all levels of the health system, and it should be adequately resourced.

American Heart Association

MedlinePlus

... reconsider sleeping in this weekend? Scientists try first gene editing in the body E-cig flavorings may damage heart muscle cells Pregnancy complication tied to heart failure risk Shakopee ... to make MRIs safer One gene may be why some people are fat Is ...

Copper Indium Gallium Diselenide Cluster Tool | Photovoltaic Research |

Science.gov Websites

-mobile unit The figure shows where chambers-numbered in the list above-are physically located on the laboratory space. Samples from the CIGS cluster tool can be transported to these other tools using a mobile

76 FR 22686 - Colorado Interstate Gas Company; Notice of Application for Abandonment

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-22

... Interstate Gas Company (CIG), Post Office Box 1087 Colorado Springs, CO 80944, filed in Docket No. CP11-186... 1087 Colorado Springs, CO 80944; telephone (719) 667-7514; facsimile (719) 667-7534; e-mail...

Nicotine delivery to users from cigarettes and from different types of e-cigarettes.

PubMed

Hajek, Peter; Przulj, Dunja; Phillips, Anna; Anderson, Rebecca; McRobbie, Hayden

2017-03-01

Delivering nicotine in the way smokers seek is likely to be the key factor in e-cigarette (EC) success in replacing cigarettes. We examined to what degree different types of EC mimic nicotine intake from cigarettes. Twelve participants ('dual users' of EC and cigarettes) used their own brand cigarette and nine different EC brands. Blood samples were taken at baseline and at 2-min intervals for 10 min and again at 30 min. Eleven smokers provided usable data. None of the EC matched cigarettes in nicotine delivery (C max  = 17.9 ng/ml, T max  = 4 min and AUC 0->30  = 315 ng/ml/min). The EC with 48 mg/ml nicotine generated the closest PK profile (C max  = 13.6 ng/ml, T max  = 4 min, AUC 0->30  = 245 ng/ml/min), followed by a third generation EC using 20 mg/ml nicotine (C max  = 11.9 ng/ml, T max  = 6 min, AUC 0->30  = 232 ng/ml/min), followed by the tank system using 20 mg/ml nicotine (C max  = 9.9 ng/ml, T max  = 6 min, AUC 0->30  = 201 ng/ml/min). Cig-a-like PK values were similar, ranging from C max 7.5 to 9.7 ng/ml, T max 4-6 min, and AUC 0->30 144 to 173 ng/ml/min. Moderate differences in e-liquid nicotine concentrations had little effect on nicotine delivery, e.g. the EC with 24 mg/ml cartridge had the same PK profile as ECs with 16 mg/ml cartridges. Using similar strength e-liquid, the tank EC provided significantly more nicotine than cig-a-like ECs. EC brands we tested do not deliver nicotine as efficiently as cigarettes, but newer EC products deliver nicotine more efficiently than cig-a-like brands. Moderate variations in nicotine content of e-liquid have little effect on nicotine delivery. Smokers who are finding cig-a-like EC unsatisfactory should be advised to try more advanced systems.

ZnS Buffer Layers Grown by Modified Chemical Bath Deposition for CIGS Solar Cells

NASA Astrophysics Data System (ADS)

Lee, Dongchan; Ahn, Heejin; Shin, Hyundo; Um, Youngho

2018-03-01

ZnS thin films were prepared by the chemical bath deposition method using disodium ethylene-diaminetetraacetic acid and hexamethylenetetramine as complexing agents in acidic conditions. The film prepared using a preheated S-ion source showed full surface coverage, but some clusters were found that were generated by the cluster-by-cluster reaction mechanism. On the other hand, the film prepared without this source had a uniform, dense, and smooth surface and showed fewer clusters than the film prepared using a preheated S-ion source. The x-ray photoelectron spectroscopy spectra showed the energy core levels of Zn, O, and S components, and Zn-OH bonding decreased on the film using the preheated S-ion source. Especially, various binding energy peaks were found in the Zn 2p 3/2 spectrum by Gaussian function fitting, and no peak corresponding to Zn-OH bonding was found for the film prepared using a preheated S-ion source. Moreover, the x-ray diffraction spectrum of the ZnS thin film using a non-preheated S-ion source showed amorphous or nanoscale crystallinity, but the emission peaks indicated that the structure of the film using preheated S-ion source was zincblende.

ZnS Buffer Layers Grown by Modified Chemical Bath Deposition for CIGS Solar Cells

NASA Astrophysics Data System (ADS)

Lee, Dongchan; Ahn, Heejin; Shin, Hyundo; Um, Youngho

2018-07-01

ZnS thin films were prepared by the chemical bath deposition method using disodium ethylene-diaminetetraacetic acid and hexamethylenetetramine as complexing agents in acidic conditions. The film prepared using a preheated S-ion source showed full surface coverage, but some clusters were found that were generated by the cluster-by-cluster reaction mechanism. On the other hand, the film prepared without this source had a uniform, dense, and smooth surface and showed fewer clusters than the film prepared using a preheated S-ion source. The x-ray photoelectron spectroscopy spectra showed the energy core levels of Zn, O, and S components, and Zn-OH bonding decreased on the film using the preheated S-ion source. Especially, various binding energy peaks were found in the Zn 2 p 3/2 spectrum by Gaussian function fitting, and no peak corresponding to Zn-OH bonding was found for the film prepared using a preheated S-ion source. Moreover, the x-ray diffraction spectrum of the ZnS thin film using a non-preheated S-ion source showed amorphous or nanoscale crystallinity, but the emission peaks indicated that the structure of the film using preheated S-ion source was zincblende.

CZTSSe: Materials and Physics Challenges

NASA Astrophysics Data System (ADS)

Gunawan, Oki

2011-03-01

Thin-film photovoltaic (PV) technologies led by CdTe and Cu(In,Ga) Se 2 (CIGS) are enjoying growing market share, due to their high performance and cost competitiveness, in the quest for renewable energy for the future. However the reliance on non-earth abundant elements tellurium and indium in these technologies presents a potential obstacle to ultimate terawatt deployment. We recently demonstrated kesterite Cu 2 ZnSn(Se,S)4 (CZTSSe) solar cells, comprised of the earth abundant metals copper, zinc and tin, with world record efficiency of 9.7%. In this talk we present a comprehensive device characterization study that pinpoints the key performance bottlenecks in these cells. We find strong buffer-absorber interface recombination and low minority carrier lifetimes that limit the open circuit voltage and a high and diverging device series resistance at lower temperature that suggests a blocking back contact that may limit the fill factor. These findings help to identify key areas for improvement for these CZTSSe cells in the pursuit of a high performance terawatt-scalable PV technology. In collaboration with Teodor K. Todorov, Aaron Barkhouse, Kejia Wang, David B. Mitzi, Supratik Guha, IBM T J Watson Research Center.

New designs and characterization techniques for thin-film solar cells

NASA Astrophysics Data System (ADS)

Pang, Yutong

This thesis presents a fundamentally new thin-film photovoltaic design and develops several novel characterization techniques that improve the accuracy of thin-film solar cell computational models by improving the accuracy of the input data. We first demonstrate a novel organic photovoltaic (OPV) design, termed a "Slot OPV", in which the active layer is less than 50 nm; We apply the principles of slot waveguides to confine light within the active layer. According to our calculation, the guided-mode absorption for a 10nm thick active layer equal to the absorption of normal incidence on an OPV with a 100nm thick active layer. These results, together with the expected improvement in charge extraction for ultrathin layers, suggest that slot OPVs can be designed with greater power conversion efficiency than today's state-of-art OPV architectures if practical challenges, such as the efficient coupling of light into these modes, can be overcome. The charge collection probability, i.e. the probability that charges generated by absorption of a photon are successfully collected as current, is a critical feature for all kinds of solar cells. While the electron-beam-induced current (EBIC) method has been used in the past to successfully reconstruct the charge collection probability, this approach is destructive and requires time-consuming sample preparation. We demonstrate a new nondestructive optoelectronic method to reconstruct the charge collection probability by analyzing the internal quantum efficiency (IQE) data that are measured on copper indium gallium diselenide (CIGS) thin-film solar cells. We further improve the method with a parameter-independent regularization approach. Then we introduce the Self-Constrained Ill-Posed Inverse Problem (SCIIP) method, which improves the signal-to-noise of the solution by using the regularization method with system constraints and optimization via an evolutionary algorithm. For a thin-film solar cell optical model to be an accurate representation of reality, the measured refractive index profile of the solar cell used as input to the model must also be accurate. We describe a new method for reconstructing the depth-dependent refractive-index profile with high spatial resolution in thin photoactive layers. This novel technique applies to any thin film, including the photoactive layers of a broad range of thin-film photovoltaics. Together, these methods help us improve the measurement accuracy of the depth profile within thin-film photovoltaics for optical and electronic properties such as refractive index and charge collection probability, which is critical to the understanding, modeling, and optimization of these devices.

Building Chronic Kidney Disease Clinical Practice Guidelines Using the openEHR Guideline Definition Language.

PubMed

Lin, Ching-Heng; Lo, Ying-Chih; Hung, Pei-Yuan; Liou, Der-Ming

2016-12-07

As a result of the disease's high prevalence, chronic kidney disease (CKD) has become a global public health problem. A clinical decision support system that integrates with computer-interpretable guidelines (CIGs) should improve clinical outcomes and help to ensure patient safety. The openEHR guideline definition language (GDL) is a formal language used to represent CIGs. This study explores the feasibility of using a GDL approach for CKD; it also attempts to identify any potential gaps between the ideal concept and reality. Using the Kidney Disease Improving Global Outcomes (KDIGO) anemia guideline as material, we designed a development workflow in order to establish a series of GDL guidelines. Focus group discussions were conducted in order to identify important issues related to GDL implementation. Ten GDL guidelines and 37 archetypes were established using the KDIGO guideline document. For the focus group discussions, 16 clinicians and 22 IT experts were recruited and their perceptions, opinions and attitudes towards the GDL approach were explored. Both groups provided positive feedback regarding the GDL approach, but raised various concerns about GDL implementation. Based on the findings of this study, we identified some potential gaps that might exist during implementation between the GDL concept and reality. Three directions remain to be investigated in the future. Two of them are related to the openEHR GDL approach. Firstly, there is a need for the editing tool to be made more sophisticated. Secondly, there needs to be integration of the present approach into non openEHR-based hospital information systems. The last direction focuses on the applicability of guidelines and involves developing a method to resolve any conflicts that occur with insurance payment regulations.

First-trimester smoking cessation in pregnancy did not increase the risk of preeclampsia/eclampsia: A Murmansk County Birth Registry study

PubMed Central

Grjibovski, Andrej M.; Krettek, Alexandra; Nieboer, Evert; Odland, Jon Ø.

2017-01-01

Background Although prior studies have shown that smoking reduces preeclampsia/eclampsia risk, the consequence of giving up this habit during pregnancy should be assessed. The aims of the current study were threefold: (i) describe maternal characteristics of women with preeclampsia/eclampsia; (ii) examine a possible association between the number of cigarettes smoked daily during pregnancy and the development of this affliction; and (iii) determine if first-trimester discontinuation of smoking during pregnancy influences the risk. Methods A registry-based study was conducted using data from the Murmansk County Birth Registry (MCBR). It included women without pre-existing hypertension, who delivered a singleton infant during 2006–2011 and had attended the first antenatal visit before 12 week of gestation. We adjusted for potential confounders using logistic regression. Results The prevalence of preeclampsia/eclampsia was 8.3% (95%CI: 8.0–8.6). Preeclampsia/eclampsia associated with maternal age, education, marital status, parity, excessive weight gain and body mass index at the first antenatal visit. There was a dose-response relationship between the number of smoked cigarettes per day during pregnancy and the risk of preeclampsia/eclampsia (adjusted OR1-5 cig/day = 0.69 with 95%CI: 0.56–0.87; OR6-10 cig/day = 0.65 with 95%CI: 0.51–0.82; and OR≥11 cig/day = 0.49 with 95%CI: 0.30–0.81). There was no difference in this risk among women who smoked before and during pregnancy and those who did so before but not during pregnancy (adjusted OR = 1.10 with 95%CI: 0.91–1.32). Conclusions Preeclampsia/eclampsia was associated with maternal age, education, marital status, parity, excessive weight gain, and body mass index at the first antenatal visit. There was a negative dose-response relationship between the number of smoked cigarettes per day during pregnancy and the odds of preeclampsia/eclampsia. However, women who gave up smoking during the first trimester of gestation had the same risk of preeclampsia/eclampsia as those who smoked while pregnant. Consequently, antenatal clinic specialists are advised to take these various observations into account when counselling women on smoking cessation during pregnancy. PMID:28797036

Determination of eugenol, anethole, and coumarin in the mainstream cigarette smoke of Indonesian clove cigarettes.

PubMed

Polzin, Gregory M; Stanfill, Stephen B; Brown, Candace R; Ashley, David L; Watson, Clifford H

2007-10-01

Indonesian clove cigarettes (kreteks), typically have the appearance of a conventional domestic cigarette. The unique aspects of kreteks are that in addition to tobacco they contain dried clove buds (15-40%, by wt.), and are flavored with a proprietary "sauce". Whereas the clove buds contribute to generating high levels of eugenol in the smoke, the "sauce" may also contribute other potentially harmful constituents in addition to those associated with tobacco use. We measured levels of eugenol, trans-anethole (anethole), and coumarin in smoke from 33 brands of clove-flavored cigarettes (filtered and unfiltered) from five kretek manufacturers. In order to provide information for evaluating the delivery of these compounds under standard smoking conditions, a quantification method was developed for their measurement in mainstream cigarette smoke. The method allowed collection of mainstream cigarette smoke particulate matter on a Cambridge filter pad, extraction with methanol, sampling by automated headspace solid-phase microextraction, and subsequent analysis using gas chromatography/mass spectrometry. The presence of these compounds was confirmed in the smoke of kreteks using mass spectral library matching, high-resolution mass spectrometry (+/-0.0002 amu), and agreement with a relative retention time index, and native standards. We found that when kreteks were smoked according to standardized machine smoke parameters as specified by the International Standards Organization, all 33 clove brands contained levels of eugenol ranging from 2,490 to 37,900 microg/cigarette (microg/cig). Anethole was detected in smoke from 13 brands at levels of 22.8-1,030 microg/cig, and coumarin was detected in 19 brands at levels ranging from 9.2 to 215 microg/cig. These detected levels are significantly higher than the levels found in commercial cigarette brands available in the United States.

Software Attribution for Geoscience Applications in the Computational Infrastructure for Geodynamics

NASA Astrophysics Data System (ADS)

Hwang, L.; Dumit, J.; Fish, A.; Soito, L.; Kellogg, L. H.; Smith, M.

2015-12-01

Scientific software is largely developed by individual scientists and represents a significant intellectual contribution to the field. As the scientific culture and funding agencies move towards an expectation that software be open-source, there is a corresponding need for mechanisms to cite software, both to provide credit and recognition to developers, and to aid in discoverability of software and scientific reproducibility. We assess the geodynamic modeling community's current citation practices by examining more than 300 predominantly self-reported publications utilizing scientific software in the past 5 years that is available through the Computational Infrastructure for Geodynamics (CIG). Preliminary results indicate that authors cite and attribute software either through citing (in rank order) peer-reviewed scientific publications, a user's manual, and/or a paper describing the software code. Attributions maybe found directly in the text, in acknowledgements, in figure captions, or in footnotes. What is considered citable varies widely. Citations predominantly lack software version numbers or persistent identifiers to find the software package. Versioning may be implied through reference to a versioned user manual. Authors sometimes report code features used and whether they have modified the code. As an open-source community, CIG requests that researchers contribute their modifications to the repository. However, such modifications may not be contributed back to a repository code branch, decreasing the chances of discoverability and reproducibility. Survey results through CIG's Software Attribution for Geoscience Applications (SAGA) project suggest that lack of knowledge, tools, and workflows to cite codes are barriers to effectively implement the emerging citation norms. Generated on-demand attributions on software landing pages and a prototype extensible plug-in to automatically generate attributions in codes are the first steps towards reproducibility.

Quit and Smoking Reduction Rates in Vape Shop Consumers: A Prospective 12-Month Survey

PubMed Central

Polosa, Riccardo; Caponnetto, Pasquale; Cibella, Fabio; Le-Houezec, Jacques

2015-01-01

Aims: Here, we present results from a prospective pilot study that was aimed at surveying changes in daily cigarette consumption in smokers making their first purchase at vape shops. Modifications in products purchase were also noted. Design: Participants were instructed how to charge, fill, activate and use their e-cigarettes (e-cigs). Participants were encouraged to use these products in the anticipation of reducing the number of cig/day smoked. Settings: Staff from LIAF contacted 10 vape shops in the province of the city of Catania (Italy) that acted as sponsors to the 2013 No Tobacco Day. Participants: 71 adult smokers (≥18 years old) making their first purchase at local participating vape shops were asked by professional retail staff to complete a form. Measurements: Their cigarette consumption was followed-up prospectively at 6 and 12 months. Details of products purchase (i.e., e-cigs hardware, e-liquid nicotine strengths and flavours) were also noted. Findings: Retention rate was elevated, with 69% of participants attending their final follow-up visit. At 12 month, 40.8% subjects could be classified as quitters, 25.4% as reducers and 33.8% as failures. Switching from standard refillables (initial choice) to more advanced devices (MODs) was observed in this study (from 8.5% at baseline to 18.4% at 12 month) as well as a trend in decreasing the e-liquid nicotine strength, with more participants adopting low nicotine strength (from 49.3% at baseline to 57.1% at 12 month). Conclusions: We have found that smokers purchasing e-cigarettes from vape shops with professional advice and support can achieve high success rates. PMID:25811767

Revisiting the Rise of Electronic Nicotine Delivery Systems Using Search Query Surveillance

PubMed Central

Ayers, John W.; Althouse, Benjamin M.; Allem, Jon-Patrick; Leas, Eric C.; Dredze, Mark; Williams, Rebecca

2016-01-01

Introduction Public perceptions of electronic nicotine delivery systems (ENDS) remain poorly understood because surveys are too costly to regularly implement and when implemented there are large delays between data collection and dissemination. Search query surveillance has bridged some of these gaps. Herein, ENDS’ popularity in the U.S. is reassessed using Google searches. Methods ENDS searches originating in the U.S. from January 2009 through January 2015 were disaggregated by terms focused on e-cigarette (e.g., e-cig) versus vaping (e.g., vapers), their geolocation (e.g., state), the aggregate tobacco control measures corresponding to their geolocation (e.g., clean indoor air laws), and by terms that indicated the searcher’s potential interest (e.g., buy e-cigs likely indicates shopping); all analyzed in 2015. Results ENDS searches are increasing across the entire U.S., with 8,498,180 searches during 2014. At the same time, searches shifted from e-cigarette- to vaping-focused terms, especially in coastal states and states with more anti-smoking norms. For example, nationally, e-cigarette searches declined 9% (95% CI=1%, 16%) during 2014 compared with 2013, whereas vaping searches increased 136% (95% CI=97%, 186%), surpassing e-cigarette searches. More ENDS searches were related to shopping (e.g., vape shop) than health concerns (e.g., vaping risks) or cessation (e.g., quit smoking with e-cigs), with shopping searches nearly doubling during 2014. Conclusions ENDS popularity is rapidly growing and evolving, and monitoring searches has provided these timely insights. These findings may inform survey questionnaire development for follow-up investigation and immediately guide policy debates about how the public perceives ENDS’ health risks or cessation benefits. PMID:26876772

Revisiting the Rise of Electronic Nicotine Delivery Systems Using Search Query Surveillance.

PubMed

Ayers, John W; Althouse, Benjamin M; Allem, Jon-Patrick; Leas, Eric C; Dredze, Mark; Williams, Rebecca S

2016-06-01

Public perceptions of electronic nicotine delivery systems (ENDS) remain poorly understood because surveys are too costly to regularly implement and, when implemented, there are long delays between data collection and dissemination. Search query surveillance has bridged some of these gaps. Herein, ENDS' popularity in the U.S. is reassessed using Google searches. ENDS searches originating in the U.S. from January 2009 through January 2015 were disaggregated by terms focused on e-cigarette (e.g., e-cig) versus vaping (e.g., vapers); their geolocation (e.g., state); the aggregate tobacco control measures corresponding to their geolocation (e.g., clean indoor air laws); and by terms that indicated the searcher's potential interest (e.g., buy e-cigs likely indicates shopping)-all analyzed in 2015. ENDS searches are rapidly increasing in the U.S., with 8,498,000 searches during 2014 alone. Increasingly, searches are shifting from e-cigarette- to vaping-focused terms, especially in coastal states and states where anti-smoking norms are stronger. For example, nationally, e-cigarette searches declined 9% (95% CI=1%, 16%) during 2014 compared with 2013, whereas vaping searches increased 136% (95% CI=97%, 186%), even surpassing e-cigarette searches. Additionally, the percentage of ENDS searches related to shopping (e.g., vape shop) nearly doubled in 2014, whereas searches related to health concerns (e.g., vaping risks) or cessation (e.g., quit smoking with e-cigs) were rare and declined in 2014. ENDS popularity is rapidly growing and evolving. These findings could inform survey questionnaire development for follow-up investigation and immediately guide policy debates about how the public perceives the health risks or cessation benefits of ENDS. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

How to create more supportive supervision for primary healthcare: lessons from Ngamiland district of Botswana: co-operative inquiry group

PubMed Central

Nkomazana, Oathokwa; Mash, Robert; Wojczewski, Silvia; Kutalek, Ruth; Phaladze, Nthabiseng

2016-01-01

Background Supportive supervision is a way to foster performance, productivity, motivation, and retention of health workforce. Nevertheless there is a dearth of evidence of the impact and acceptability of supportive supervision in low- and middle-income countries. This article describes a participatory process of transforming the supervisory practice of district health managers to create a supportive environment for primary healthcare workers. Objective The objective of the study was to explore how district health managers can change their practice to create a more supportive environment for primary healthcare providers. Design A facilitated co-operative inquiry group (CIG) was formed with Ngamiland health district managers. CIG belongs to the participatory action research paradigm and is characterised by a cyclic process of observation, reflection, planning, and action. The CIG went through three cycles between March 2013 and March 2014. Results Twelve district health managers participated in the inquiry group. The major insights and learning that emerged from the inquiry process included inadequate supervisory practice, perceptions of healthcare workers’ experiences, change in the managers’ supervision paradigm, recognition of the supervisors’ inadequate supervisory skills, and barriers to supportive supervision. Finally, the group developed a 10-point consensus on what they had learnt regarding supportive supervision. Conclusion Ngamiland health district managers have come to appreciate the value of supportive supervision and changed their management style to be more supportive of their subordinates. They also developed a consensus on supportive supervision that could be adapted for use nationally. Supportive supervision should be prioritised at all levels of the health system, and it should be adequately resourced. PMID:27345024

Peri-implant parameters, tumor necrosis factor-alpha, and interleukin-1 beta levels in vaping individuals.

PubMed

Al-Aali, Khulud A; Alrabiah, Mohammed; ArRejaie, Aws S; Abduljabbar, Tariq; Vohra, Fahim; Akram, Zohaib

2018-03-25

To the author's knowledge, there has been no study that has assessed clinical, radiographic, and immunological peri-implant parameters among individuals vaping e-cigarette (e-cig). This pilot study aimed to compare clinical and radiographic peri-implant parameters and levels of tumor necrosis factor alpha (TNF-α) and interleukin (IL)-1β levels among individuals vaping e-cigs and never smoker (NS). Forty-seven individuals vaping e-cigs (group-1) and 45 NS (group-2) were included. Demographic and implant-related data were collected using a structured baseline questionnaire. Peri-implant plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were recorded and peri-implant bone loss (PIBL) were assessed using standardized digital radiographs. Enzyme-linked immunosorbent assay was used to assess the levels of TNF-α and IL-1β in peri-implant sulcular fluid. Bleeding on probing showed statistically significantly higher values in group-2 patients as compared to group-1 patients (P < .01). Probing depth ≥ 4 mm and PIBL was statistically significantly higher in group-1 patients as compared to group-2 patients (P < .05). Mean concentrations of TNF-α (P < .001) and IL-1β (P < .01) were statistically significantly increased in individuals in group 1 as compared with group 2. A significant positive correlations were found between TNF-α levels and BOP (P = .024) and PIBL (P = .016); and significant positive correlation was found between IL-1β and PIBL (P = .018) in group 1, respectively. Clinical and radiographic peri-implant parameters are compromised among vaping individuals. Increased levels of proinflammatory cytokines in peri-implant sulcular fluid may suggest greater local inflammatory response in vaping individuals for peri-implant inflammation. © 2018 Wiley Periodicals, Inc.

76 FR 48812 - Privacy Act of 1974; System of Records

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-09

... closed case listings used to manage investigations, to produce statistical reports, and to control..., Department of Defense. CIG-26 System Name: Case Control System--Investigative System Location: Department of... Number (SSN), address, case control number, records of investigations to include Reports of Investigation...

Decoding the phosphorylation code in Hedgehog signal transduction

PubMed Central

Chen, Yongbin; Jiang, Jin

2013-01-01

Hedgehog (Hh) signaling plays pivotal roles in embryonic development and adult tissue homeostasis, and its deregulation leads to numerous human disorders including cancer. Binding of Hh to Patched (Ptc), a twelve-transmembrane protein, alleviates its inhibition of Smoothened (Smo), a seven-transmembrane protein related to G-protein-coupled receptors (GPCRs), leading to Smo phosphorylation and activation. Smo acts through intracellular signaling complexes to convert the latent transcription factor Cubitus interruptus (Ci)/Gli from a truncated repressor to a full-length activator, leading to derepression/activation of Hh target genes. Increasing evidence suggests that phosphorylation participates in almost every step in the signal relay from Smo to Ci/Gli, and that differential phosphorylation of several key pathway components may be crucial for translating the Hh morphogen gradient into graded pathway activities. In this review, we focus on the multifaceted roles that phosphorylation plays in Hh signal transduction, and discuss the conservation and difference between Drosophila and mammalian Hh signaling mechanisms. PMID:23337587

Long-term performance analysis of CIGS thin-film PV modules

NASA Astrophysics Data System (ADS)

Dhere, Neelkanth G.; Kaul, Ashwani; Pethe, Shirish A.

2011-09-01

Current accelerated qualification tests of photovoltaic (PV) modules mostly assist in avoiding infant mortality but can neither duplicate changes occurring in the field nor can predict useful lifetime. Therefore, outdoor monitoring of fielddeployed thin-film PV modules was undertaken at FSEC with goals of assessing their performance in hot and humid climate under high system voltage operation and to correlate the PV performance with the meteorological parameters. Significant and comparable degradation rate of -5.13% and -4.5% per year was found by PV USA type regression analysis for the positive and negative strings respectively of 40W glass-to-glass CIGS thin-film PV modules in the hot and humid climate of Florida. With the current-voltage measurements it was found that the performance degradation within the PV array was mainly due to a few (8-12%) modules having a substantially high degradation. The remaining modules within the array continued to show reasonable performance (>96% of the rated power after ~ 4years).

A complex solution to a sexual dilemma.

PubMed

Kuwabara, Patricia E

2007-07-01

The C. elegans male sex-determining protein, FEM-1, has been identified as a substrate recognition subunit of a Cullin-2 ubiquitin ligase complex. This complex controls the level of TRA-1A, a Ci/Gli homolog and master regulator of sex determination, by ubiquitin-mediated proteolysis.

78 FR 45185 - Privacy Act of 1974; System of Records

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-26

... DEPARTMENT OF DEFENSE Office of the Secretary [Docket ID DoD-2013-OS-0166] Privacy Act of 1974.... FOR FURTHER INFORMATION CONTACT: Mark Dorgan, DoD IG FOIA/Privacy Office, Department of Defense... OSD Federal Register Liaison Officer, Department of Defense. CIG-16 System name: DoD Hotline Program...

75 FR 52935 - Colorado Interstate Gas Company; Notice of Application

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-30

... Interstate Gas Company (CIG), P.O. Box 1087, Colorado Springs, Colorado 80944, pursuant to section 7(c) of.... Susan C. Stires, Director, Regulatory Affairs, Colorado Interstate Gas Company, P.O. Box 1087, Colorado... President and General Counsel, Colorado Interstate Gas Company; P.O. Box 1087, Colorado Springs, Colorado...

Environmental Impacts from Photovoltaic Solar Cells Made with Single Walled Carbon Nanotubes.

PubMed

Celik, Ilke; Mason, Brooke E; Phillips, Adam B; Heben, Michael J; Apul, Defne

2017-04-18

An ex-ante life cycle inventory was developed for single walled carbon nanotube (SWCNT) PV cells, including a laboratory-made 1% efficient device and an aspirational 28% efficient four-cell tandem device. The environmental impact of unit energy generation from the mono-Si PV technology was used as a reference point. Compared to monocrystalline Si (mono-Si), the environmental impacts from 1% SWCNT was ∼18 times higher due mainly to the short lifetime of three years. However, even with the same short lifetime, the 28% cell had lower environmental impacts than mono-Si. The effects of lifetime and efficiency on the environmental impacts were further examined. This analysis showed that if the SWCNT device efficiency had the same value as the best efficiency of the material under comparison, to match the total normalized impacts of the mono- and poly-Si, CIGS, CdTe, and a-Si devices, the SWCNT devices would need a lifetime of 2.8, 3.5, 5.3, 5.1, and 10.8 years, respectively. It was also found that if the SWCNT PV has an efficiency of 4.5% or higher, its energy payback time would be lower than other existing and emerging PV technologies. The major impacts of SWCNT PV came from the cell's materials synthesis.

75 FR 30806 - Colorado Interstate Gas Company; Notice of Application

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-02

... Interstate Gas Company (CIG), P.O. Box 1087, Colorado Springs, Colorado 80944, filed with the Federal Energy... Susan C. Stires, Director, Regulatory Affairs, Colorado Interstate Gas Company, P.O. Box 1087, Colorado..., P.O. Box 1087, Colorado Springs, Colorado 80944 at 719-520-4898. Pursuant to section 157.9 of the...

Multiple-Color-Generating Cu(In,Ga)(S,Se)2 Thin-Film Solar Cells via Dichroic Film Incorporation for Power-Generating Window Applications.

PubMed

Yoo, Gang Yeol; Jeong, Jae-Seung; Lee, Soyoung; Lee, Youngki; Yoon, Hee Chang; Chu, Van Ben; Park, Gi Soon; Hwang, Yun Jeong; Kim, Woong; Min, Byoung Koun; Do, Young Rag

2017-05-03

There are four prerequisites when applying all types of thin-film solar cells to power-generating window photovoltaics (PVs): high power-generation efficiency, longevity and high durability, semitransparency or partial-light transmittance, and colorful and aesthetic value. Solid-type thin-film Cu(In,Ga)S 2 (CIGS) or Cu(In,Ga)(S,Se) 2 (CIGSSe) PVs nearly meet the first two criteria, making them promising candidates for power-generating window applications if they can transmit light to some degree and generate color with good aesthetic value. In this study, the mechanical scribing process removes 10% of the window CIGSSe thin-film solar cell with vacant line patterns to provide a partial-light-transmitting CIGSSe PV module to meet the third requirement. The last concept of creating distinct colors could be met by the addition of reflectance colors of one-dimensional (1D) photonic crystal (PC) dichroic film on the black part of a partial-light-transmitting CIGSSe PV module. Beautiful violets and blues were created on the cover glass of a black CIGSSe PV module via the addition of 1D PC blue-mirror-yellow-pass dichroic film to improve the aesthetic value of the outside appearance. As a general result from the low external quantum efficiency (EQE) and absorption of CIGSSe PVs below a wavelength of 400 nm, the harvesting efficiency and short-circuit photocurrent of CIGSSe PVs were reduced by only ∼10% without reducing the open-circuit voltage (V OC ) because of the reduced overlap between the absorption spectrum of CIGSSe PV and the reflectance spectrum of the 1D PC blue-mirror-yellow-pass dichroic film. The combined technology of partial-vacancy-scribed CIGSSe PV modules and blue 1D PC dichroic film can provide a simple strategy to be applied to violet/blue power-generating window applications, as such a strategy can improve the transparency and aesthetic value without significantly sacrificing the harvesting efficiency of the CIGSSe PV modules.

Lung Toxicity of Condensed Aerosol from E-CIG Liquids: Influence of the Flavor and the In Vitro Model Used.

PubMed

Bengalli, Rossella; Ferri, Emanuele; Labra, Massimo; Mantecca, Paride

2017-10-20

The diffusion of e-cigarette (e-CIG) opens a great scientific and regulatory debate about its safety. The huge number of commercialized devices, e-liquids with almost infinite chemical formulations and the growing market demand for a rapid and efficient toxicity screen system that is able to test all of these references and related aerosols. A consensus on the best protocols for the e-CIG safety assessment is still far to be achieved, since the huge number of variables characterizing these products (e.g., flavoring type and concentration, nicotine concentration, type of the device, including the battery and the atomizer). This suggests that more experimental evidences are needed to support the regulatory frameworks. The present study aims to contribute in this field by testing the effects of condensed aerosols (CAs) from three main e-liquid categories (tobacco, mint, and cinnamon as food-related flavor), with (18 mg/mL) or without nicotine. Two in vitro models, represented by a monoculture of human epithelial alveolar cells and a three-dimensional (3D) co-culture of alveolar and lung microvascular endothelial cells were used. Cell viability, pro-inflammatory cytokines release and alveolar-blood barrier (ABB) integrity were investigated as inhalation toxicity endpoints. Results showed that nicotine itself had almost no influence on the modulation of the toxicity response, while flavor composition did have. The cell viability was significantly decreased in monoculture and ABB after exposure to the mints and cinnamon CAs. The barrier integrity was significantly affected in the ABB after exposure to cytotoxic CAs. With the exception of the significant IL-8 release in the monoculture after Cinnamon exposure, no increase of inflammatory cytokines (IL-8 and MCP-1) release was observed. These findings point out that multiple assays with different in vitro models are able to discriminate the acute inhalation toxicity of CAs from liquids with different flavors, providing the companies and regulatory bodies with useful tools for the preliminary screening of marketable products.

Cigarettes vs. e-cigarettes: Passive exposure at home measured by means of airborne marker and biomarkers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballbè, Montse; Catalan Network of Smoke-free Hospitals, L'Hospitalet de Llobregat, Barcelona; Cancer Prevention and Control Group, Institut d'Investigació Biomèdica de Bellvitge – IDIBELL, L’Hospitalet de Llobregat, Barcelona

Background: There is scarce evidence about passive exposure to the vapour released or exhaled from electronic cigarettes (e-cigarettes) under real conditions. The aim of this study is to characterise passive exposure to nicotine from e-cigarettes' vapour and conventional cigarettes' smoke at home among non-smokers under real-use conditions. Methods: We conducted an observational study with 54 non-smoker volunteers from different homes: 25 living at home with conventional smokers, 5 living with nicotine e-cigarette users, and 24 from control homes (not using conventional cigarettes neither e-cigarettes). We measured airborne nicotine at home and biomarkers (cotinine in saliva and urine). We calculated geometricmore » mean (GM) and geometric standard deviations (GSD). We also performed ANOVA and Student's t tests for the log-transformed data. We used Bonferroni-corrected t-tests to control the family error rate for multiple comparisons at 5%. Results: The GMs of airborne nicotine were 0.74 μg/m{sup 3} (GSD=4.05) in the smokers’ homes, 0.13 μg/m{sup 3} (GSD=2.4) in the e-cigarettes users’ homes, and 0.02 μg/m{sup 3} (GSD=3.51) in the control homes. The GMs of salivary cotinine were 0.38 ng/ml (GSD=2.34) in the smokers’ homes, 0.19 ng/ml (GSD=2.17) in the e-cigarettes users’ homes, and 0.07 ng/ml (GSD=1.79) in the control homes. Salivary cotinine concentrations of the non-smokers exposed to e-cigarette's vapour at home (all exposed ≥2 h/day) were statistically significant different that those found in non-smokers exposed to second-hand smoke ≥2 h/day and in non-smokers from control homes. Conclusions: The airborne markers were statistically higher in conventional cigarette homes than in e-cigarettes homes (5.7 times higher). However, concentrations of both biomarkers among non-smokers exposed to conventional cigarettes and e-cigarettes’ vapour were statistically similar (only 2 and 1.4 times higher, respectively). The levels of airborne nicotine and cotinine concentrations in the homes with e-cigarette users were higher than control homes (differences statistically significant). Our results show that non-smokers passively exposed to e-cigarettes absorb nicotine. - Highlights: • This is the first study of e-cigarette exposure at home under real-use conditions. • Airborne nicotine in homes with smokers were 5.7 times higher than in e-cig homes. • Cotinine of non-smokers exposed to e-cig and conventional cigarettes was similar. • Airborne nicotine in homes with e-cig users was higher than control homes. • Cotinine of non-smokers exposed to e-cig users was higher than in those no exposed.« less

Photovoltaic Manufacturing Consortium (PVMC) – Enabling America’s Solar Revolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metacarpa, David

The U.S. Photovoltaic Manufacturing Consortium (US-PVMC) is an industry-led consortium which was created with the mission to accelerate the research, development, manufacturing, field testing, commercialization, and deployment of next-generation solar photovoltaic technologies. Formed as part of the U.S. Department of Energy's (DOE) SunShot initiative, and headquartered in New York State, PVMC is managed by the State University of New York Polytechnic Institute (SUNY Poly) at the Colleges of Nanoscale Science and Engineering. PVMC is a hybrid of industry-led consortium and manufacturing development facility, with capabilities for collaborative and proprietary industry engagement. Through its technology development programs, advanced manufacturing development facilities,more » system demonstrations, and reliability and testing capabilities, PVMC has demonstrated itself to be a recognized proving ground for innovative solar technologies and system designs. PVMC comprises multiple locations, with the core manufacturing and deployment support activities conducted at the Solar Energy Development Center (SEDC), and the core Si wafering and metrology technologies being headed out of the University of Central Florida. The SEDC provides a pilot line for proof-of-concept prototyping, offering critical opportunities to demonstrate emerging concepts in PV manufacturing, such as evaluations of innovative materials, system components, and PV system designs. The facility, located in Halfmoon NY, encompasses 40,000 square feet of dedicated PV development space. The infrastructure and capabilities housed at PVMC includes PV system level testing at the Prototype Demonstration Facility (PDF), manufacturing scale cell & module fabrication at the Manufacturing Development Facility (MDF), cell and module testing, reliability equipment on its PV pilot line, all integrated with a PV performance database and analytical characterizations for PVMC and its partners test and commercial arrays. Additional development and deployment support are also housed at the SEDC, such as cost modeling and cost model based development activities for PV and thin film modules, components, and system level designs for reduced LCOE through lower installation hardware costs, labor reductions, soft costs and reduced operations and maintenance costs. The progression of the consortium activities started with infrastructure and capabilities build out focused on CIGS thin film photovoltaics, with a particular focus on flexible cell and module production. As marketplace changes and partners objectives shifted, the consortium shifted heavily towards deployment and market pull activities including Balance of System, cost modeling, and installation cost reduction efforts along with impacts to performance and DER operational costs. The consortium consisted of a wide array of PV supply chain companies from equipment and component suppliers through national developers and installers with a particular focus on commercial scale deployments (typically 25 to 2MW installations). With DOE funding ending after the fifth budget period, the advantages and disadvantages of such a consortium is detailed along with potential avenues for self-sustainability is reviewed.« less

75 FR 60097 - Colorado Interstate Gas Company; Notice of Intent To Prepare An Environmental Assessment for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-29

... Proposed Project CIG proposes to construct and operate a new air blending station in Douglas County... Spruce Hill Air Blending Project would consist of the following: An air blending compressor station (the Spruce Hill Air Blending Station) containing a 215-, a 390-, and a 500-horsepower air compressor; A back...

75 FR 60441 - Colorado Interstate Gas Company; Notice of Intent To Prepare an Environmental Assessment for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-30

... Proposed Project CIG proposes to construct and operate a new air blending station in Douglas County... Spruce Hill Air Blending Project would consist of the following: An air blending compressor station (the Spruce Hill Air Blending Station) containing a 215-, a 390-, and a 500-horsepower air compressor; A back...

The Availability of Indium: The Present, Medium Term, and Long Term

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lokanc, Martin; Eggert, Roderick; Redlinger, Michael

2015-10-01

Demand for indium is likely to increase if the growth in deployment of the copper-indium-gallium-selenide (CIGS) and III-V thin-film photovoltaic technologies accelerates. There are concerns about indium supply constraints since it is relatively rare element in the earth's crust and because it is produced exclusively as a byproduct.

"Shifts in Thinking" in Arts Teachers' Narratives: Documentation as Inquiry and Artifact

ERIC Educational Resources Information Center

Meier, Mary Elizabeth

2012-01-01

In this narrative inquiry, I analyzed art and music teachers' stories of professional learning as they engaged in the study of their teaching practice in a collaborative inquiry group (CIG). During two years of data collection, I examined stories that arts teachers told when describing classroom photographs, images of student work, video…

Online Vape Shop Customers Who Use E-Cigarettes Report Abstinence from Smoking and Improved Quality of Life, But a Substantial Minority Still Have Vaping-Related Health Concerns

PubMed Central

Van Gucht, Dinska; Adriaens, Karolien; Baeyens, Frank

2017-01-01

(1) Background: Characteristics and usage patterns of vapers (e-cigarette users) have mainly been studied in web-based convenience samples or in visitors of brick-and-mortar vape shops. We extended this by targeting customers of one particular online vape shop in the Netherlands; (2) Methods: Customers were questioned on their smoking history, current smoking and vaping status, reasons for vaping, perceived harmfulness, and potential health changes due to vaping; (3) Results: Almost everyone (99%, 95% CI 0.96, 1.00) smoked before they started vaping. A great majority agreed that unlike with other smoking-cessation aids, they could quit smoking (81%, 95% CI 0.79, 0.90) due to vaping. Almost all customers were regular vapers (93.6%, 95% CI 0.89, 0.96) who used state-of-the-art open system devices without modifications and e-liquid with 10 mg/mL nicotine on average. Vapers reported using e-cigs to quit smoking, because e-cigs are healthier, and for financial reasons. The majority (52.6%, 95% CI 0.46, 0.60) perceived vaping as not that harmful to not harmful at all, but one fifth (21.8%, 95% CI 0.16, 0.28) believed vaping to be harmful. More than half (57.8%, 95% CI 0.50, 0.65) reported gaining more pleasure from vaping than from smoking. A substantial majority (84.2%, 95% CI 0.78, 0.89) agreed that their health had improved since they started vaping; (4) Conclusions: Findings are similar to those obtained in other vape shop studies, but also to the results of convenience samples of less-well-defined populations. PMID:28714914

Online Vape Shop Customers Who Use E-Cigarettes Report Abstinence from Smoking and Improved Quality of Life, But a Substantial Minority Still Have Vaping-Related Health Concerns.

PubMed

Gucht, Dinska Van; Adriaens, Karolien; Baeyens, Frank

2017-07-17

(1) Background: Characteristics and usage patterns of vapers (e-cigarette users) have mainly been studied in web-based convenience samples or in visitors of brick-and-mortar vape shops. We extended this by targeting customers of one particular online vape shop in the Netherlands; (2) Methods: Customers were questioned on their smoking history, current smoking and vaping status, reasons for vaping, perceived harmfulness, and potential health changes due to vaping; (3) Results: Almost everyone (99%, 95% CI 0.96, 1.00) smoked before they started vaping. A great majority agreed that unlike with other smoking-cessation aids, they could quit smoking (81%, 95% CI 0.79, 0.90) due to vaping. Almost all customers were regular vapers (93.6%, 95% CI 0.89, 0.96) who used state-of-the-art open system devices without modifications and e-liquid with 10 mg/mL nicotine on average. Vapers reported using e-cigs to quit smoking, because e-cigs are healthier, and for financial reasons. The majority (52.6%, 95% CI 0.46, 0.60) perceived vaping as not that harmful to not harmful at all , but one fifth (21.8%, 95% CI 0.16, 0.28) believed vaping to be harmful. More than half (57.8%, 95% CI 0.50, 0.65) reported gaining more pleasure from vaping than from smoking. A substantial majority (84.2%, 95% CI 0.78, 0.89) agreed that their health had improved since they started vaping; (4) Conclusions: Findings are similar to those obtained in other vape shop studies, but also to the results of convenience samples of less-well-defined populations.

Commanding Heterogeneous Multi-Robot Teams

DTIC Science & Technology

2014-06-01

Coalition Battle Management Language (C-BML) Study Group Report. 2005 Fall Simulation Interoperability Workshop (05F- SIW - 041), Orlando, FL, September...NMSG-085 CIG Land Operation Demonstration. 2013 Spring Simulation Interoperability Workshop (13S- SIW -031), San Diego, CA. April 2013. [4] K...Simulation Interoperability Workshop (10F- SIW -039), Orlando, FL, September 2010. [5] M. Langerwisch, M. Ax, S. Thamke, T. Remmersmann, A. Tiderko

77 FR 51792 - Colorado Interstate Gas Company, L.L.C.; Notice of Application

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-27

... Interstate Gas Company, L.L.C.; Notice of Application Take notice that on August 7, 2012, Colorado Interstate Gas Company, L.L.C. (CIG), Post Office Box 1087, Colorado Springs, Colorado 80944, filed in the above captioned docket an application pursuant to section 7(c) of the Natural Gas Act (NGA) for a certificate of...

[Vaping: a new strategy to prevent smoking-related diseases?].

PubMed

Polosa, Riccardo

2014-01-01

By quitting, smokers of all ages can gain substantial health benefits. No other single effort of public health is able to achieve an advantage comparable to smoking cessation on a large scale. However, conventional approaches to smoking cessation require tobacco users to completely abstain, and many smokers are unable - or have not the willingness - to achieve this goal, and then continue to smoke despite the looming negative consequences for health. But it is possible to consider another option: the reduction of harm caused by tobacco smoking (tobacco harm reduction) through the intake of nicotine from alternative sources safer than tobacco smoke, such as the electronic cigarette (e-cig). It is a promising product for the reduction of harm caused by tobacco smoking. In addition to providing nicotine through the vapour without the typical toxic and carcinogenic substances derived from combustion, the e-cig is also a good substitute for the rituals associated with the behaviour of the smoker. In this article, the author suggests that the wide dissemination of vaping behaviour can become a successful strategy to reduce smoking and preventing smoking-related diseases, advancing on how to succeed with this matter.

Preparation and Layer-by-Layer Solution Deposition of Cu(In,Ga)O2 Nanoparticles with Conversion to Cu(In,Ga)S2 Films

PubMed Central

Dressick, Walter J.; Soto, Carissa M.; Fontana, Jake; Baker, Colin C.; Myers, Jason D.; Frantz, Jesse A.; Kim, Woohong

2014-01-01

We present a method of Cu(In,Ga)S2 (CIGS) thin film formation via conversion of layer-by-layer (LbL) assembled Cu-In-Ga oxide (CIGO) nanoparticles and polyelectrolytes. CIGO nanoparticles were created via a novel flame-spray pyrolysis method using metal nitrate precursors, subsequently coated with polyallylamine (PAH), and dispersed in aqueous solution. Multilayer films were assembled by alternately dipping quartz, Si, and/or Mo substrates into a solution of either polydopamine (PDA) or polystyrenesulfonate (PSS) and then in the CIGO-PAH dispersion to fabricate films as thick as 1–2 microns. PSS/CIGO-PAH films were found to be inadequate due to weak adhesion to the Si and Mo substrates, excessive particle diffusion during sulfurization, and mechanical softness ill-suited to further processing. PDA/CIGO-PAH films, in contrast, were more mechanically robust and more tolerant of high temperature processing. After LbL deposition, films were oxidized to remove polymer and sulfurized at high temperature under flowing hydrogen sulfide to convert CIGO to CIGS. Complete film conversion from the oxide to the sulfide is confirmed by X-ray diffraction characterization. PMID:24941104

CuSb(S,Se)2 thin film heterojunction photovoltaic devices

NASA Astrophysics Data System (ADS)

Welch, Adam W.

Thin film heterojunction solar cells based on CuSb(S,Se)2 absorbers are investigated for two primary reasons. First, antimony is more abundant and less expensive than elements used in current thin film photovoltaics, In, Ga, and Te, and so, successful integration of Sb based materials offers greater diversification and scalability of solar energy. Second, the CuSb(S,Se) 2 ternary is chemically, electronically, and optically similar to the well-known, high efficiency, CuIn(S,Se)2 based materials. It is therefore postulated that the copper antimony ternaries will have similar defect tolerant electronic transport that may allow for similar highly efficient photoconversion. However, CuSb(S,Se)2 forms a layered crystal structure, different from the tetrahedral coordination found in conventional solar absorbers, due to the non-bonding lone pair of electrons on the antimony site. Thus examination of 2D antimony ternaries will lend insight into the role of structure in photoconversion processes. To address these questions, the semiconductors of interest (CuSbS 2 & CuSbSe2) were first synthesized on glass by combinatorial methods, to more quickly optimize process condi- tions. Radio-frequency (RF) magnetron co-sputtering from Sb2(S,Se)3 and Cu 2(S,Se) targets were used, without rotation, to produce chemical and flux graded libraries which were then subjected to high throughput characterization of structure (XRD), composition (XRF), conductivity (4pp), and optical absorption (UV/Vis/NIR). This approach rapidly identified processes that generated phase pure material with tunable carrier concentration by applying excess Sb 2(S,Se)3 within a temperature window bound by the volatility of Sb2(S,Se)3 and stability of the ternary phase. The resulting phase pure thin films were then incor- porated into the traditional CuInGaSe2 (CIGS) substrate photovoltaic (PV) architecture, and the resulting device performance was correlated to gradients in composition, sputter flux, absorber thickness, and grain orientation. This combinatorial work was complimented by individual measurements of photoluminescence (PL), capacitance-voltage (CV), external quantum efficiency (EQE), terahertz (THz) spectroscopy, and photoelectrochemical (PEC) measurements. CuSbS2-based libraries produced devices with just 1% power conversion efficiency, mainly limited by high levels of recombination associated with high density of shallow trap states. Conversely, the selenide variant showed more promise, with initial cells producing significantly more photocurrent, nearly 60% of the theoretical maximum, and likewise 5% efficient devices, mainly due to fewer trap states. However, the selenide is still limited by short carrier diffusion lengths, therefore demonstrating that structure does seem to play limiting role in photoconversion processes. Overall, the CuSb(S,Se)2 material system is only likely to merit further exploration if it can be incorporated into an alternate device structure less dependent on collection by diffusion. There is a small possibility that oriented selenide films with anisotropic carrier lifetimes could improve performance, though this is unlikely considering initial oriented sulfide films did not demonstrate much improved performance. This work demonstrated the utility of the combinatorial device fabrication applied to the search for new, scalable photovoltaic materials. An innovative chemical system was quickly explored in-depth and optimized for devices; continued efforts of this type are likely to produce better materials, or at the very least, quickly expand the library of well-scrutinized photovoltaic materials.

Elastic and optical properties of Cu2ZnSn(SexS1 - x)4 alloys: density functional calculations

NASA Astrophysics Data System (ADS)

Camps, I.; Coutinho, J.; Mir, M.; da Cunha, A. F.; Rayson, M. J.; Briddon, P. R.

2012-11-01

Cu2ZnSn(S1 - xSex)4 (CZT(S, Se)) is emerging as a very credible alternative to CuIn1 - xGaxSe2 (CIGS) as the absorber layer for thin film solar cells. The former compound has the important advantage of using abundant Zn and Sn instead of the expensive In and Ga. A better understanding of the properties of CZT(S, Se) is being sought through experimental and theoretical means. Thus far, however, very little is known about the fundamental properties of the CZT(S, Se) alloys. In this work, theoretical studies on the structural, elastic, electronic and optical properties of CZT(S, Se) alloys through first-principles calculations are reported. We use a density functional code (aimpro), along with the Padé parametrization for the local density approximation to the exchange correlation potential. For the alloying calculations we employed 64 atom supercells (approximately cubic) with a 2 × 2 × 2 k-point sampling set. These supercells possess a total of 32 chalcogen species and the CZTSexS1 - x alloys are described by using the ordered alloy approximation. Accordingly, to create a perfectly diluted alloying host, the species type of the 32 chalcogen sites is selected randomly with uniform probability x and 1 - x for Se and S, respectively. Properties of alloys (structural, elastic, electronic and optical) are obtained by averaging the results of ten supercell configurations generated for each composition. For each configuration, lattice vectors and atomic positions were allowed to relax (although enforcing the tetragonal lattice type) and the Murnaghan equation of state was fitted to the total energy data. The results presented here permit a better understanding of the properties of the CZT(S, Se) alloys which in turn result in the design of more efficient solar cells.

77 FR 58122 - Colorado Interstate Gas Company, L.L.C.; Notice of Intent To Prepare an Environmental Assessment...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-19

... accordance with state law. CIG provided landowners with a fact sheet prepared by the FERC entitled ``An... used to measure new sources of supply into the existing High Plains System; Modify an existing meter... notice in the mail and are available at www.ferc.gov using the link called ``eLibrary'' or from the...

Training and Personnel Systems Technology R&D Program Description FY 1988/1989. Revision

DTIC Science & Technology

1988-05-20

scenario software /database, and computer generated imagery (CIG) subsystem resources; (d) investigation of feasibility of, and preparation of plans... computer language to Army flight simulator for demonstration and evaluation. The objective is to have flight simulators which use the same software as...the Automated Performance and Readiness Training System (APARTS), which is a computer software system which facilitates training management through

Lung Toxicity of Condensed Aerosol from E-CIG Liquids: Influence of the Flavor and the In Vitro Model Used

PubMed Central

Bengalli, Rossella; Ferri, Emanuele; Labra, Massimo; Mantecca, Paride

2017-01-01

The diffusion of e-cigarette (e-CIG) opens a great scientific and regulatory debate about its safety. The huge number of commercialized devices, e-liquids with almost infinite chemical formulations and the growing market demand for a rapid and efficient toxicity screen system that is able to test all of these references and related aerosols. A consensus on the best protocols for the e-CIG safety assessment is still far to be achieved, since the huge number of variables characterizing these products (e.g., flavoring type and concentration, nicotine concentration, type of the device, including the battery and the atomizer). This suggests that more experimental evidences are needed to support the regulatory frameworks. The present study aims to contribute in this field by testing the effects of condensed aerosols (CAs) from three main e-liquid categories (tobacco, mint, and cinnamon as food-related flavor), with (18 mg/mL) or without nicotine. Two in vitro models, represented by a monoculture of human epithelial alveolar cells and a three-dimensional (3D) co-culture of alveolar and lung microvascular endothelial cells were used. Cell viability, pro-inflammatory cytokines release and alveolar-blood barrier (ABB) integrity were investigated as inhalation toxicity endpoints. Results showed that nicotine itself had almost no influence on the modulation of the toxicity response, while flavor composition did have. The cell viability was significantly decreased in monoculture and ABB after exposure to the mints and cinnamon CAs. The barrier integrity was significantly affected in the ABB after exposure to cytotoxic CAs. With the exception of the significant IL-8 release in the monoculture after Cinnamon exposure, no increase of inflammatory cytokines (IL-8 and MCP-1) release was observed. These findings point out that multiple assays with different in vitro models are able to discriminate the acute inhalation toxicity of CAs from liquids with different flavors, providing the companies and regulatory bodies with useful tools for the preliminary screening of marketable products. PMID:29053606

Emitter/absorber interface of CdTe solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Tao, E-mail: tsong241@gmail.com; Sites, James R.; Kanevce, Ana

The performance of CdTe solar cells can be very sensitive to the emitter/absorber interface, especially for high-efficiency cells with high bulk lifetime. Performance losses from acceptor-type interface defects can be significant when interface defect states are located near mid-gap energies. Numerical simulations show that the emitter/absorber band alignment, the emitter doping and thickness, and the defect properties of the interface (i.e., defect density, defect type, and defect energy) can all play significant roles in the interface recombination. In particular, a type I heterojunction with small conduction-band offset (0.1 eV ≤ ΔE{sub C} ≤ 0.3 eV) can help maintain good cell efficiency in spite of high interfacemore » defect density, much like with Cu(In,Ga)Se{sub 2} (CIGS) cells. The basic principle is that positive ΔE{sub C}, often referred to as a “spike,” creates an absorber inversion and hence a large hole barrier adjacent to the interface. As a result, the electron-hole recombination is suppressed due to an insufficient hole supply at the interface. A large spike (ΔE{sub C} ≥ 0.4 eV), however, can impede electron transport and lead to a reduction of photocurrent and fill-factor. In contrast to the spike, a “cliff” (ΔE{sub C} < 0 eV) allows high hole concentration in the vicinity of the interface, which will assist interface recombination and result in a reduced open-circuit voltage. Another way to mitigate performance losses due to interface defects is to use a thin and highly doped emitter, which can invert the absorber and form a large hole barrier at the interface. CdS is the most common emitter material used in CdTe solar cells, but the CdS/CdTe interface is in the cliff category and is not favorable from the band-offset perspective. The ΔE{sub C} of other n-type emitter choices, such as (Mg,Zn)O, Cd(S,O), or (Cd,Mg)Te, can be tuned by varying the elemental ratio for an optimal positive value of ΔE{sub C}. These materials are predicted to yield higher voltages and would therefore be better candidates for the CdTe-cell emitter.« less

Improved measurement of carbonaceous aerosol in Beijing, China: intercomparison of sampling and thermal-optical analysis methods

NASA Astrophysics Data System (ADS)

Cheng, Y.; He, K. B.; Duan, F. K.; Zheng, M.; Ma, Y. L.; Tan, J. H.; Du, Z. Y.

2010-06-01

The sampling artifacts (both positive and negative) and the influence of thermal-optical methods (both charring correction method and the peak inert mode temperature) on the split of organic carbon (OC) and elemental carbon (EC) were evaluated in Beijing. The positive sampling artifact constituted 10% and 23% of OC concentration determined by the bare quartz filter during winter and summer, respectively. For summer samples, the adsorbed gaseous organics were found to continuously evolve off the filter during the whole inert mode when analyzed by the IMPROVE-A temperature protocol. This may be due to the oxidation of the adsorbed organics during sampling (reaction artifact) which would increase their thermal stability. The backup quartz approach was evaluated by a denuder-based method for assessing the positive artifact. The quartz-quartz (QBQ) in series method was demonstrated to be reliable, since all of the OC collected by QBQ was from originally gaseous organics. Negative artifact that could be adsorbed by quartz filter was negligible. When the activated carbon impregnated glass fiber (CIG) filter was used as the denuded backup filter, the denuder efficiency for removing gaseous organics that could be adsorbed by the CIG filter was only about 30%. EC values were found to differ by a factor of about two depending on the charring correction method. Influence of the peak inert mode temperature was evaluated based on the summer samples. The EC value was found to continuously decrease with the peak inert mode temperature. Premature evolution of light absorbing carbon began when the peak inert mode temperature was increased from 580 to 650 °C; when further increased to 800 °C, the OC and EC split frequently occurred in the He mode, and the last OC peak was characterized by the overlapping of two separate peaks. The discrepancy between EC values defined by different temperature protocols was larger for Beijing carbonaceous aerosol compared with North America and Europe, perhaps due to the higher concentration of brown carbon in Beijing aerosol.

Combat Vehicle Command and Control System Architecture Overview

DTIC Science & Technology

1994-10-01

inserted in the software. • Interactive interface displays and controls were prepared using rapidly prototyped software and were retained at the MWTB for...being simulated "* controls , sensor displays, and out-the-window displays for the crew "* computer image generators (CIGs) for out-the-window and...black hot viewing modes. The commander may access a number of capabilities of the CITV simulation, described below, from controls located around the

78 FR 78946 - Privacy Act of 1974; System of Records

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-27

...The Office of the Inspector General (OIG) is amending a system of records notice, CIG-21, Congressional Correspondence Tracking System, in its existing inventory of record systems subject to the Privacy Act of 1974 (5 U.S.C. 552a), as amended. This system maintains records of all Congressional inquiries and the OIG, DoD response, and to conduct the necessary research to provide information responsive to Congressional inquiries.

Graphene oxide bound silica for solid-phase extraction of 14 polycyclic aromatic hydrocarbons in mainstream cigarette smoke.

PubMed

Shi, Rui; Yan, Lihong; Xu, Tongguang; Liu, Dongye; Zhu, Yongfa; Zhou, Jun

2015-01-02

Polycyclic aromatic hydrocarbons (PAHs) were considered as a source of carcinogenicity in mainstream cigarette smoke (MSS). Accurate quantification of these components was necessary for assessing public health risk. In our study, a solid-phase extraction (SPE) method using graphene oxide (GO) bound silica as adsorbent for purification of 14 PAHs in MSS was developed. During SPE process, large matrices interferences of MSS were adsorbed on SPE column. The result of FTIR spectra demonstrated that these matrices interferences were adsorbed on GO mainly through OH and CO groups. The concentrations of PAHs in MSS extract were determined by gas chromatography-mass spectrometry (GC-MS). The limit of detection (LOD) and limit of quantification (LOQ) of the developed method for 14 PAHs ranged from 0.05 to 0.36 ng/cig and 0.17 to 1.19 ng/cig, respectively. The accuracy of the measurement of 14 PAHs was from 73 to 116%. The relative standard deviations of intra- and inter-day analysis were less than 7.8% and 13.9%, respectively. Moreover, the developed method was successfully applied for analysis of real cigarette containing 1R5F reference cigarette and 12 top-selling commercial cigarettes in China. Copyright © 2014 Elsevier B.V. All rights reserved.

Thin-film photovoltaic power generation offers decreasing greenhouse gas emissions and increasing environmental co-benefits in the long term.

PubMed

Bergesen, Joseph D; Heath, Garvin A; Gibon, Thomas; Suh, Sangwon

2014-08-19

Thin-film photovoltaic (PV) technologies have improved significantly recently, and similar improvements are projected into the future, warranting reevaluation of the environmental implications of PV to update and inform policy decisions. By conducting a hybrid life cycle assessment using the most recent manufacturing data and technology roadmaps, we compare present and projected environmental, human health, and natural resource implications of electricity generated from two common thin-film PV technologies-copper indium gallium selenide (CIGS) and cadmium telluride (CdTe)-in the United States (U.S.) to those of the current U.S. electricity mix. We evaluate how the impacts of thin films can be reduced by likely cost-reducing technological changes: (1) module efficiency increases, (2) module dematerialization, (3) changes in upstream energy and materials production, and (4) end-of-life recycling of balance of system (BOS). Results show comparable environmental and resource impacts for CdTe and CIGS. Compared to the U.S. electricity mix in 2010, both perform at least 90% better in 7 of 12 and at least 50% better in 3 of 12 impact categories, with comparable land use, and increased metal depletion unless BOS recycling is ensured. Technological changes, particularly efficiency increases, contribute to 35-80% reductions in all impacts by 2030.

The effect of Se/Te ratio on transient absorption behavior and nonlinear absorption properties of CuIn0.7Ga0.3(Se1-xTex)2 (0 ≤ x ≤ 1) amorphous semiconductor thin films

NASA Astrophysics Data System (ADS)

Karatay, Ahmet; Küçüköz, Betül; Çankaya, Güven; Ates, Aytunc; Elmali, Ayhan

2017-11-01

The characterization of the CuInSe2 (CIS), CuInGaSe (CIGS) and CuGaSe2 (CGS) based semiconductor thin films are very important role for solar cell and various nonlinear optical applications. In this paper, the amorphous CuIn0.7Ga0.3(Se1-xTex)2 semiconductor thin films (0 ≤ x ≤ 1) were prepared with 60 nm thicknesses by using vacuum evaporation technique. The nonlinear absorption properties and ultrafast transient characteristics were investigated by using open aperture Z-scan and ultrafast pump-probe techniques. The energy bandgap values were calculated by using linear absorption spectra. The bandgap values are found to be varying from 0.67 eV to 1.25 eV for CuIn0.7Ga0.3Te2, CuIn0.7Ga0.3Se1.6Te0.4, CuIn0.7Ga0.3Se0.4Te1.6 and CuIn0.7Ga0.3Se2 thin films. The energy bandgap values decrease with increasing telluride (Te) doping ratio in mixed CuIn0.7Ga0.3(Se1-xTex)2 films. This affects nonlinear characteristics and ultrafast dynamics of amorphous thin films. Ultrafast pump-probe experiments indicated that decreasing of bandgap values with increasing the Te amount switches from the excited state absorption signals to ultrafast bleaching signals. Open aperture Z-scan experiments show that nonlinear absorption properties enhance with decreasing bandgaps values for 65 ps pulse duration at 1064 nm. Highest nonlinear absorption coefficient was found for CuIn0.7Ga0.3Te2 thin film due to having the smallest energy bandgap.

Studies of the synthesis and deposition of Cu3BiS 3 for use in photovoltaic devices

NASA Astrophysics Data System (ADS)

Epstein, Joshua A.

As the world's climate continues to change, alternative energy is being adopted more and more. Solar energy is one extremely promising candidate to supplement our ever increasing energy needs. In order for it to be a viable solution, more efficient and less expensive solar panels must be made. While silicon solar panels are the current market leader their high manufacturing energy input and cost warrant looking into alternatives. Many thin film solar materials are being investigated such as CdTe, CIGS and CZTS, but all come with their own drawbacks. With a near ideal band gap, low toxicity and earth abundant elemental make up copper bismuth sulfide, Cu3BiS3, is a promising candidate for use in future photovoltaic devices. The research presented here details multiple methods to synthesize and deposit this material with an effort to keep the methods low cost, energy efficient and environmentally friendly. Multiple low temperature solvothermal routes to synthesizing copper bismuth sulfide, CBS, have been developed. The resulting powders have been verified as pure Cu3BiS3 via XRD peak matching. The precursor reactants tested for use were copper and bismuth nitrates, acetates, chlorides and hydroxides. L-cystine, L-cysteine, thiourea and CS2 have all been tested for use as sulfur sources. Seven of these combinations produced pure CBS powders. Two custom built benchtop reactors have been designed and fabricated with the aim of studying the possibility of a continuous flow reactor as a way to utilize these precipitation chemistries for making thin films of CBS. Heat and liquid flow simulations were performed in COMSOL multiphysics to assist in the reactor design process. The second reactor was designed to promote uniform liquid flow across the fluorine doped, tin oxide coated, FTO, glass. This reactor was also built with a temperature gradient transverse to the liquid flow so that the optimal temperature for the deposition of CBS could be evaluated. This reactor was also used to evaluate the deposition of CdS, an n-type semiconductor often used in thin film solar panels, onto FTO glass. CBS thin films were also prepared via electrodeposition and thermal treatment. The solution used was a mixture of copper nitrate, sodium sulfite and sodium citrate tribasic dihydrate dissolved in DI H2O and bismuth nitrate dissolved in ethylene glycol. To get the best coating it was found that the electrodeposition should be done at 1.2 V and last 5 minutes. Thermal treatment carried out in a 450°C tube furnace for 90 min in forming gas (95% N2 with 5% H2) along with sulfur vapor was proved best. No further treatment was required to obtain phase pure CBS coatings. This was verified with XRD peak analysis. Optical absorption, microstructural, and photoconductivity data are reported for CBS materials made using the above techniques.

Puffing Topography and Nicotine Intake of Electronic Cigarette Users

PubMed Central

Behar, Rachel Z.; Hua, My; Talbot, Prue

2015-01-01

Background Prior electronic cigarette (EC) topography data are based on two video analyses with limited parameters. Alternate methods for measuring topography are needed to understand EC use and nicotine intake. Objectives This study evaluated EC topography with a CReSS Pocket device and quantified nicotine intake. Methods Validation tests on pressure drop, flow rate, and volume confirmed reliable performance of the CReSS Pocket device. Twenty participants used Blu Cigs and V2 Cigs for 10 minute intervals with a 10–15 minute break between brands. Brand order was reversed and repeated within 7 days Data were analyzed to determine puff duration, puff count, volume, flow rate, peak flow, and inter-puff interval. Nicotine intake was estimated from cartomizer fluid consumption and topography data. Results Nine patterns of EC use were identified. The average puff count and inter-puff interval were 32 puffs and 17.9 seconds. All participants, except one, took more than 20 puffs/10 minutes. The averages for puff duration (2.65 seconds/puff), volume/puff (51ml/puff), total puff volume (1,579 ml), EC fluid consumption (79.6 mg), flow rate (20 ml/s), and peak flow rate (27 ml/s) were determined for 10-minute sessions. All parameters except total puff count were significantly different for Blu versus V2 EC. Total volume for Blu versus V2 was four-times higher than for conventional cigarettes. Average nicotine intake for Blu and V2 across both sessions was 1.2 ± 0.5 mg and 1.4 ± 0.7 mg, respectively, which is similar to conventional smokers. Conclusions EC puffing topography was variable among participants in the study, but often similar within an individual between brands or days. Puff duration, inter-puff interval, and puff volume varied from conventional cigarette standards. Data on total puff volume and nicotine intake are consistent with compensatory usage of EC. These data can contribute to the development of a standard protocol for laboratory testing of EC products. PMID:25664463

Exploiting Temporal Constraints of Clinical Guidelines by Applying OpenEHR Archetypes.

PubMed

Cintho, Lilian Mie Mukai; Garcia, Diego; da Silva Santos, Bruno Henrique; Sacchi, Lucia; Quaglini, Silvana; Moro, Claudia Maria Cabral

2017-01-01

Studies describing Computer-Interpretable Clinical Guidelines (CIG) with temporal constrains (TC) generally have not addressed issues related to their integration into Electronic Health Record (EHR) systems. This study aimed to represent TCs contained in clinical guidelines by applying archetypes and Guideline Definition Language (GDL) to incorporate decision support into EHRs. An example of each TC class in the clinical guideline for management of Atrial Fibrillation was represented using archetypes and GDL.

Effects of copper excess and copper deficiency on the structural and electrical properties of bulk Cu{sub x}SnSe{sub 3} with x=1.6–2.2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wubet, Walelign; Kuo, Dong-Hau, E-mail: dhkuo@mail.ntust.edu.tw

2015-03-15

Effects of the Cu variation on the morphological, structural, and electrical properties of bulk Cu{sub x}SnSe{sub 3} (CTSe) with x=1.6–2.2 have been investigated. Dense CTSe pellets with grains of 3–4 µm were obtained after sintering at 550 °C. All CTSe pellets showed a dominant p-type behavior. CTSe at x=2.0 with a hole concentration (n{sub p}) of 1.02×10{sup 18} cm{sup −3} and Hall mobility (μ) of 225 cm{sup 2}/V/s had a highest conductivity (σ) of 39 S/cm. CTSe at x=1.6 with n{sub p} of 5.0×10{sup 17} cm{sup −3} and of 11 cm{sup 2}/V/s had a lowest of 0.90 S/cm. The explanation,more » based upon vacancies and antisite defects, for the changes in electrical property with the Cu content is supported by the data from lattice parameter. The study in bulk properties of CTSe and its defects is helpful for selecting the suitable absorber composition to fabricate thin film solar cells. - Graphical abstract: Cu{sub 2}SnSe{sub 3} is an absorber candidate for solar cells. The Cu stoichiometry on electrical properties, which is important for CIGS and CZTS, is investigated and the Cu-deficiency composition is recommended. - Highlights: • Cu{sub x}SnSe{sub 3} (CTSe) bulks with 1.6≤x≤2.2 were prepared by reactive sintering. • Cu{sub 2}SnSe{sub 3} with n{sub p} of 1.02×10{sup 18} cm{sup −3} and μ of 225 cm{sup 2}/V/s had highest σ of 39 S/cm. • Cu{sub 1.6}SnSe{sub 3} with n{sub p}=5.0×10{sup 17} cm{sup −3} and μ=11 cm{sup 2}/V/s had lowest σ=0.90 S/cm. • Lower n{sub p} at CTSe at x=1.6 is related to the formation of the Sn-to-Cu defect. • The drop in n{sub p} for CTSe at x=2.2 indicates V{sub Sn}{sup 4−} dominates over Cu{sub Sn}{sup 3−} defect.« less

The Potential That Electronic Nicotine Delivery Systems Can be a Disruptive Technology: Results From a National Survey.

PubMed

Pechacek, Terry F; Nayak, Pratibha; Gregory, Kyle R; Weaver, Scott R; Eriksen, Michael P

2016-10-01

This study evaluates the reasons for use and acceptance of Electronic Nicotine Delivery Systems (ENDS) among current and former cigarette smokers to assess if ENDS may become a satisfying alternative to cigarettes. Data are from a national probability sample of 5717 US adults, surveyed June-November 2014. The survey contained questions on awareness, usage, and reasons for use of traditional and novel tobacco products. The analytic sample was current and former smokers who ever used ENDS (n = 729) and was divided into four mutually exclusive categories. Among the 585 current smokers, 337 were no longer using ENDS ("E-Cig Rejecters"), and 248 were continuing to use both ENDS and cigarettes ("E-Cig Dual Users"). Among 144 former cigarette smokers, 101 were non-recent users of ENDS ("Quit All Products"), and 43 were continuing to use ENDS exclusively ("Switchers"). Former smokers (the "Switchers") report finding ENDS a satisfying alternative to regular cigarettes, with only 15.8% (95% confidence interval [CI] 4.4-27.1) rating ENDS as less enjoyable than regular cigarettes. However, greater than fivefold more current smokers did not find them satisfying and stopped using them (77.3%; 95% CI 72.1-82.4 of "E-Cig Rejecters" rated ENDS as less enjoyable). Being less harmful was the most highly rated reason for continuing to use ENDS among "Switchers." Most (80.9%) "Switchers" reported that ENDS helped them quit cigarettes. Since many current smokers who have tried ENDS reject them as a satisfying alternative to regular cigarettes, ENDS will not replace regular cigarettes unless they improve. Since about one-half of recent former smokers are trying ENDS with about one-fourth continuing to use them, and many reporting that these products have helped them quit regular cigarettes, the potential impact of ENDS on population quit rates deserves continued surveillance. However, since most current smokers who have tried ENDS reject them as a satisfying alternative to regular cigarettes, the potential of ENDS becoming a disruptive technology replacing regular cigarettes remains uncertain. ENDS need to improve as a satisfying alternative or the attractiveness and appeal of the regular cigarette must be degraded to increase the potential of ENDS replacing regular cigarettes. © The Author 2016. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco.

The Potential That Electronic Nicotine Delivery Systems Can be a Disruptive Technology: Results From a National Survey

PubMed Central

Nayak, Pratibha; Gregory, Kyle R.; Weaver, Scott R.; Eriksen, Michael P.

2016-01-01

Introduction: This study evaluates the reasons for use and acceptance of Electronic Nicotine Delivery Systems (ENDS) among current and former cigarette smokers to assess if ENDS may become a satisfying alternative to cigarettes. Methods: Data are from a national probability sample of 5717 US adults, surveyed June–November 2014. The survey contained questions on awareness, usage, and reasons for use of traditional and novel tobacco products. The analytic sample was current and former smokers who ever used ENDS (n = 729) and was divided into four mutually exclusive categories. Among the 585 current smokers, 337 were no longer using ENDS (“E-Cig Rejecters”), and 248 were continuing to use both ENDS and cigarettes (“E-Cig Dual Users”). Among 144 former cigarette smokers, 101 were non-recent users of ENDS (“Quit All Products”), and 43 were continuing to use ENDS exclusively (“Switchers”). Results: Former smokers (the “Switchers”) report finding ENDS a satisfying alternative to regular cigarettes, with only 15.8% (95% confidence interval [CI] 4.4–27.1) rating ENDS as less enjoyable than regular cigarettes. However, greater than fivefold more current smokers did not find them satisfying and stopped using them (77.3%; 95% CI 72.1–82.4 of “E-Cig Rejecters” rated ENDS as less enjoyable). Being less harmful was the most highly rated reason for continuing to use ENDS among “Switchers.” Most (80.9%) “Switchers” reported that ENDS helped them quit cigarettes. Conclusion: Since many current smokers who have tried ENDS reject them as a satisfying alternative to regular cigarettes, ENDS will not replace regular cigarettes unless they improve. Implications: Since about one-half of recent former smokers are trying ENDS with about one-fourth continuing to use them, and many reporting that these products have helped them quit regular cigarettes, the potential impact of ENDS on population quit rates deserves continued surveillance. However, since most current smokers who have tried ENDS reject them as a satisfying alternative to regular cigarettes, the potential of ENDS becoming a disruptive technology replacing regular cigarettes remains uncertain. ENDS need to improve as a satisfying alternative or the attractiveness and appeal of the regular cigarette must be degraded to increase the potential of ENDS replacing regular cigarettes. PMID:27142201

Assessment of a personalized and distributed patient guidance system.

PubMed

Peleg, Mor; Shahar, Yuval; Quaglini, Silvana; Broens, Tom; Budasu, Roxana; Fung, Nick; Fux, Adi; García-Sáez, Gema; Goldstein, Ayelet; González-Ferrer, Arturo; Hermens, Hermie; Hernando, M Elena; Jones, Val; Klebanov, Guy; Klimov, Denis; Knoppel, Daniel; Larburu, Nekane; Marcos, Carlos; Martínez-Sarriegui, Iñaki; Napolitano, Carlo; Pallàs, Àngels; Palomares, Angel; Parimbelli, Enea; Pons, Belén; Rigla, Mercedes; Sacchi, Lucia; Shalom, Erez; Soffer, Pnina; van Schooten, Boris

2017-05-01

The MobiGuide project aimed to establish a ubiquitous, user-friendly, patient-centered mobile decision-support system for patients and for their care providers, based on the continuous application of clinical guidelines and on semantically integrated electronic health records. Patients would be empowered by the system, which would enable them to lead their normal daily lives in their regular environment, while feeling safe, because their health state would be continuously monitored using mobile sensors and self-reporting of symptoms. When conditions occur that require medical attention, patients would be notified as to what they need to do, based on evidence-based guidelines, while their medical team would be informed appropriately, in parallel. We wanted to assess the system's feasibility and potential effects on patients and care providers in two different clinical domains. We describe MobiGuide's architecture, which embodies these objectives. Our novel methodologies include a ubiquitous architecture, encompassing a knowledge elicitation process for parallel coordinated workflows for patients and care providers; the customization of computer-interpretable guidelines (CIGs) by secondary contexts affecting remote management and distributed decision-making; a mechanism for episodic, on demand projection of the relevant portions of CIGs from a centralized, backend decision-support system (DSS), to a local, mobile DSS, which continuously delivers the actual recommendations to the patient; shared decision-making that embodies patient preferences; semantic data integration; and patient and care provider notification services. MobiGuide has been implemented and assessed in a preliminary fashion in two domains: atrial fibrillation (AF), and gestational diabetes Mellitus (GDM). Ten AF patients used the AF MobiGuide system in Italy and 19 GDM patients used the GDM MobiGuide system in Spain. The evaluation of the MobiGuide system focused on patient and care providers' compliance to CIG recommendations and their satisfaction and quality of life. Our evaluation has demonstrated the system's capability for supporting distributed decision-making and its use by patients and clinicians. The results show that compliance of GDM patients to the most important monitoring targets - blood glucose levels (performance of four measurements a day: 0.87±0.11; measurement according to the recommended frequency of every day or twice a week: 0.99±0.03), ketonuria (0.98±0.03), and blood pressure (0.82±0.24) - was high in most GDM patients, while compliance of AF patients to the most important targets was quite high, considering the required ECG measurements (0.65±0.28) and blood-pressure measurements (0.75±1.33). This outcome was viewed by the clinicians as a major potential benefit of the system, and the patients have demonstrated that they are capable of self-monitoring - something that they had not experienced before. In addition, the system caused the clinicians managing the AF patients to change their diagnosis and subsequent treatment for two of the ten AF patients, and caused the clinicians managing the GDM patients to start insulin therapy earlier in two of the 19 patients, based on system's recommendations. Based on the end-of-study questionnaires, the sense of safety that the system has provided to the patients was its greatest asset. Analysis of the patients' quality of life (QoL) questionnaires for the AF patients was inconclusive, because while most patients reported an improvement in their quality of life in the EuroQoL questionnaire, most AF patients reported a deterioration in the AFEQT questionnaire. Feasibility and some of the potential benefits of an evidence-based distributed patient-guidance system were demonstrated in both clinical domains. The potential application of MobiGuide to other medical domains is supported by its standards-based patient health record with multiple electronic medical record linking capabilities, generic data insertion methods, generic medical knowledge representation and application methods, and the ability to communicate with a wide range of sensors. Future larger scale evaluations can assess the impact of such a system on clinical outcomes. MobiGuide's feasibility was demonstrated by a working prototype for the AF and GDM domains, which is usable by patients and clinicians, achieving high compliance to self-measurement recommendations, while enhancing the satisfaction of patients and care providers. Copyright © 2017 Elsevier B.V. All rights reserved.

Cost Benefit Analysis of Integrated COTS Energy- Related Technologies for Army’s Force Provider Module

DTIC Science & Technology

2009-09-01

Year Defense Plan (FYDP), on which the Department of Defense operates, subsequently needs 26 Richard G. Lugar, U.S. Senator for Indiana , “U.S...mature thin-film technologies exist such as Amorphous Silicon (a-Si), Cadmium Telluride (CdTe), and Copper Indium Gallium (di) Selenide (CIGS), all...cheaper processing, lower material costs, and is free of the environmental and health hazard issues of cadmium . Amorphous silicon coupled with

Formation of selenide, sulfide or mixed selenide-sulfide films on metal or metal coated substrates

DOEpatents

Eser, Erten; Fields, Shannon

2012-05-01

A process and composition for preventing cracking in composite structures comprising a metal coated substrate and a selenide, sulfide or mixed selenide sulfide film. Specifically, cracking is prevented in the coating of molybdenum coated substrates upon which a copper, indium-gallium diselenide (CIGS) film is deposited. Cracking is inhibited by adding a Se passivating amount of oxygen to the Mo and limiting the amount of Se deposited on the Mo coating.

Application of Thin Film Photovoltaic CIGS Cells to Extend the Endurance of Small Unmanned Aerial Systems

DTIC Science & Technology

2017-06-01

Sherif Michael Second Reader: James Calusdian THIS PAGE INTENTIONALLY LEFT BLANK i REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704–0188...Unclassified 19. SECURITY CLASSIFICATION OF ABSTRACT Unclassified 20. LIMITATION OF ABSTRACT UU NSN 7540–01-280-5500 Standard Form 298 (Rev. 2–89...States Military utilizes an extensive variety of UAVs, whether electric or fossil fuel propulsion. In this section, we review the distinctive sorts of

Application of Copper Indium Gallium Diselenide Photovoltaic Cells to Extend the Endurance and Capabilities of Unmanned Aerial Vehicles

DTIC Science & Technology

2009-09-01

Group V element to make them n or p material. Another common group of semiconductors are called III–V compounds , such as gallium arsenide (GaAs), or...these compounds used for photovoltaics are Cadmium Telluride (CdTe), and Copper Indium Gallium DiSelenide, commonly referred to as CIGS [49]. Figure...INDIUM GALLIUM DISELENIDE PHOTOVOLTAIC CELLS TO EXTEND THE ENDURANCE AND CAPABILITIES OF UNMANNED AERIAL VEHICLES by William R. Hurd

Creating Shareable Clinical Decision Support Rules for a Pharmacogenomics Clinical Guideline Using Structured Knowledge Representation.

PubMed

Linan, Margaret K; Sottara, Davide; Freimuth, Robert R

2015-01-01

Pharmacogenomics (PGx) guidelines contain drug-gene relationships, therapeutic and clinical recommendations from which clinical decision support (CDS) rules can be extracted, rendered and then delivered through clinical decision support systems (CDSS) to provide clinicians with just-in-time information at the point of care. Several tools exist that can be used to generate CDS rules that are based on computer interpretable guidelines (CIG), but none have been previously applied to the PGx domain. We utilized the Unified Modeling Language (UML), the Health Level 7 virtual medical record (HL7 vMR) model, and standard terminologies to represent the semantics and decision logic derived from a PGx guideline, which were then mapped to the Health eDecisions (HeD) schema. The modeling and extraction processes developed here demonstrate how structured knowledge representations can be used to support the creation of shareable CDS rules from PGx guidelines.

Solar Adaptive Optics.

PubMed

Rimmele, Thomas R; Marino, Jose

Adaptive optics (AO) has become an indispensable tool at ground-based solar telescopes. AO enables the ground-based observer to overcome the adverse effects of atmospheric seeing and obtain diffraction limited observations. Over the last decade adaptive optics systems have been deployed at major ground-based solar telescopes and revitalized ground-based solar astronomy. The relatively small aperture of solar telescopes and the bright source make solar AO possible for visible wavelengths where the majority of solar observations are still performed. Solar AO systems enable diffraction limited observations of the Sun for a significant fraction of the available observing time at ground-based solar telescopes, which often have a larger aperture than equivalent space based observatories, such as HINODE. New ground breaking scientific results have been achieved with solar adaptive optics and this trend continues. New large aperture telescopes are currently being deployed or are under construction. With the aid of solar AO these telescopes will obtain observations of the highly structured and dynamic solar atmosphere with unprecedented resolution. This paper reviews solar adaptive optics techniques and summarizes the recent progress in the field of solar adaptive optics. An outlook to future solar AO developments, including a discussion of Multi-Conjugate AO (MCAO) and Ground-Layer AO (GLAO) will be given. Supplementary material is available for this article at 10.12942/lrsp-2011-2.

Surface Observation Climatic Summaries for Richards-Gebaur AFB, Missouri

DTIC Science & Technology

1991-04-01

SUPERSEDES: N/A APR 91 LST TOUTC 406 I MONTH IJAN I FEB I MAR IAP IMAY I JUN I JUL IAUG ISEP IOCT INOV I DEC IANN IYOR- EXTRN MAX TERP(F) 71 82 85 92 94 104...ANDVSBILIT *JN I FEB IAR IM I JUN I JUL IAUG IsEP I OCT I V I DEC I YOR LST 00 - 02 10 03 - 05 10 CIG 06 - 08 23.8 31.5 31.0 22.1 24.0 15.0 12.7 17.4

How to manage organisational change and create practice teams: experiences of a South African primary care health centre.

PubMed

Mash, B J; Mayers, P; Conradie, H; Orayn, A; Kuiper, M; Marais, J

2008-07-01

In South Africa, first-contact primary care is delivered by nurses in small clinics and larger community health centres (CHC). CHCs also employ doctors, who often work in isolation from the nurses, with poor differentiation of roles and little effective teamwork or communication. Worcester CHC, a typical public sector CHC in rural South Africa, decided to explore how to create more successful practice teams of doctors and nurses. This paper is based on their experience of both unsuccessful and successful attempts to introduce practice teams and reports on their learning regarding organisational change. An emergent action research study design utilised a co-operative inquiry group. The first nine months of inquiry focused on understanding the initial unsuccessful attempt to create practice teams. This paper reports primarily on the subsequent nine months (four cycles of planning, action, observation and reflection) during which practice teams were re-introduced. The central question was how more effective practice teams of doctors and nurses could be created. The group utilised outcome mapping to assist with planning, monitoring and evaluation. Outcome mapping defined a vision, mission, boundary partners, outcome challenges, progress markers and strategies for the desired changes and supported quantitative monitoring of the process. Qualitative data were derived from the co-operative inquiry group (CIG) meetings and interviews with doctors, nurses, practice teams and patients. The CIG engaged effectively with 68% of the planned strategies, and more than 60% of the progress markers were achieved for clinical nurse practitioners, doctors, support staff and managers, but not for patients. Key themes that emerged from the inquiry group's reflection on their experience of the change process dealt with the amount of interaction, type of communication, team resilience, staff satisfaction, leadership style, reflective capacity, experimentation and evolution of new structures. The group's learning supported a view of change that sees the organisation as a living system in which information flow, participation and the development of resilience are key aspects. These themes fit well into an understanding of change based on complexity theory. If managers of the health system wish to enhance organisational change, then their goal may need to shift from optimising health care delivery in a mechanistic model to optimising health care workers in a living system.

A review on solar cells from Si-single crystals to porous materials and quantum dots

PubMed Central

Badawy, Waheed A.

2013-01-01

Solar energy conversion to electricity through photovoltaics or to useful fuel through photoelectrochemical cells was still a main task for research groups and developments sectors. In this article we are reviewing the development of the different generations of solar cells. The fabrication of solar cells has passed through a large number of improvement steps considering the technological and economic aspects. The first generation solar cells were based on Si wafers, mainly single crystals. Permanent researches on cost reduction and improved solar cell efficiency have led to the marketing of solar modules having 12–16% solar conversion efficiency. Application of polycrystalline Si and other forms of Si have reduced the cost but on the expense of the solar conversion efficiency. The second generation solar cells were based on thin film technology. Thin films of amorphous Si, CIS (copper–indium–selenide) and t-Si were employed. Solar conversion efficiencies of about 12% have been achieved with a remarkable cost reduction. The third generation solar cells are based on nano-crystals and nano-porous materials. An advanced photovoltaic cell, originally developed for satellites with solar conversion efficiency of 37.3%, based on concentration of the solar spectrum up to 400 suns was developed. It is based on extremely thin concentration cells. New sensitizer or semiconductor systems are necessary to broaden the photo-response in solar spectrum. Hybrids of solar and conventional devices may provide an interim benefit in seeking economically valuable devices. New quantum dot solar cells based on CdSe–TiO2 architecture have been developed. PMID:25750746

A review on solar cells from Si-single crystals to porous materials and quantum dots.

PubMed

Badawy, Waheed A

2015-03-01

Solar energy conversion to electricity through photovoltaics or to useful fuel through photoelectrochemical cells was still a main task for research groups and developments sectors. In this article we are reviewing the development of the different generations of solar cells. The fabrication of solar cells has passed through a large number of improvement steps considering the technological and economic aspects. The first generation solar cells were based on Si wafers, mainly single crystals. Permanent researches on cost reduction and improved solar cell efficiency have led to the marketing of solar modules having 12-16% solar conversion efficiency. Application of polycrystalline Si and other forms of Si have reduced the cost but on the expense of the solar conversion efficiency. The second generation solar cells were based on thin film technology. Thin films of amorphous Si, CIS (copper-indium-selenide) and t-Si were employed. Solar conversion efficiencies of about 12% have been achieved with a remarkable cost reduction. The third generation solar cells are based on nano-crystals and nano-porous materials. An advanced photovoltaic cell, originally developed for satellites with solar conversion efficiency of 37.3%, based on concentration of the solar spectrum up to 400 suns was developed. It is based on extremely thin concentration cells. New sensitizer or semiconductor systems are necessary to broaden the photo-response in solar spectrum. Hybrids of solar and conventional devices may provide an interim benefit in seeking economically valuable devices. New quantum dot solar cells based on CdSe-TiO2 architecture have been developed.

First-principles study of SnS electronic properties using LDA, PBE and HSE06 functionals

NASA Astrophysics Data System (ADS)

Ibragimova, R.; Ganchenkova, M.; Karazhanov, S.; Marstein, E. S.

2018-03-01

Recently, tin sulphide (SnS) has emerged as a promising alternative to conventional CIGS and CZTC for use in solar cells, possessing such properties as non-toxicity, low cost and production stability. SnS has a high theoretically predicted efficiency above 20%, but the experimentally achieved efficiency so far is as low as 4.36%. The reason for the low achieved efficiency is unclear. One of the powerful tools to get deeper insights about the nature of the problem is first-principles calculation approaches. That is why SnS has become an attractive subject for first-principles calculations recently. Previously calculated data, however, show a widespread of such fundamental value as the bandgap varying from 0.26 to 1.26 eV. In order to understand a reason for that, in this work, we concentrate on a systematic study of calculation parameters effects on the resulting electronic structure, with the particular attention paid to the influence of the exchange-correlation functional chosen for calculations. Several exchange-correlation functionals (LDA, PBE and HSE06) were considered. The systematic analysis has shown that the bandgap variation can result from a tensile/compressive hydrostatic pressure introduced by non-equilibrium lattice parameters used for the calculations. The study of the applicability of three functionals has shown that HSE06 gives the best match to both experimentally obtained bandgap and the XPS valence band spectra. LDA underestimates the bandgap but qualitatively reproduces experimentally measured valence DOS similar to that of HSE06 in contrast to PBE. PBE underestimates the bandgap and does not match to the measured XPS spectra.

Transparent and semitransparent conducting film deposition by reactive-environment, hollow cathode sputtering

NASA Astrophysics Data System (ADS)

Delahoy, A. E.; Guo, S. Y.

2005-07-01

Highly transparent and conductive In2O3 and ZnO films containing different doping elements such as Ti, Mo, Zr, Nb, Ta, W (for In2O3), and B (for ZnO) have been prepared by reactive-environment, hollow cathode sputtering (RE-HCS). The use of Nb and W as effective dopants is reported for the first time. Metallic targets were used exclusively, and the dopant concentration was easily controlled using a second sputtering power supply. As a result of the cathode and gas flow geometry, the sputtering is conducted in metal mode, and the target and doping materials are free from oxidation during the deposition process. Film resistivities achieved with the various dopants are reported. For In2O3:Mo (IMO), a resistivity of 1.6×10-4Ω cm and a mobility of 80 cm2/Vs were achieved for Mo concentrations in the range 0.5-5.0% as measured by inductively coupled plasma (ICP). X-ray photoelectron spectroscopy (XPS) analysis indicates Mo with a +6 valence state and that the film is stoichiometric. For In2O3:Ti (ITiO), a superior optical transmission is achieved relative to IMO, while carrier mobility and conductivity were similar. Remarkably, semitransparent films of InN:O having sheet resistances of 9.5 Ω/square have also been prepared. ZnO:B films deposited by RE-HCS exhibit superior optical properties relative to ZnO:Al, and when applied as a window layer to CIGS solar cells yield higher quantum efficiencies.

Activities of the task group 8 on thin film PV module reliability (Conference Presentation)

NASA Astrophysics Data System (ADS)

Dhere, Neelkanth G.

2016-09-01

Photovoltaic (PV) modules and systems are being used increasingly to provide renewable energy to schools, residences, small businesses and utilities. At this time, the home owners and small businesses have considerable difficulty in detecting module and/or system degradation and especially enforcing warranty. It needs to be noted that IEC 61215-1 (test req.), -2 (test proc.) and -1-1 (c-Si) are forecasted to be circulated end of Feb 2016 and only editorial changes would be possible. 61215 series does include thin film technologies and would be replacing 61646. Moreover, IEC 61215-1, section 7.2 power output and electric circuitry does contain significant changes to acceptance criteria regarding rated label values, particularly rated power. Even though it is believed that consensus could be achieved within IEC TC82 WG2, some of the smaller players that do not participate actively in IEC TC82 - may not be surprised and must be informed. The other tech specific parts 61215-1-2 (CdTe), -1-3 (a-Si, µc-Si) and -1-4 (CIS, CIGS) are out for comments. The IEC closing date was January 29, 2016. The additions alternative damp heat (DH) test proposed Solar Frontier is being reviewed. In the past, only 600 V systems were permitted in the grid-connected residential and commercial systems in the US. The US commercial systems can now use higher voltage (1,000-1500V) in order to reduce BOS component costs. It is believed that there would not be any problems. The Task Group 8 is collecting data on higher voltage systems.

Lack of difference between continuous versus intermittent heparin infusion on maintenance of intra-arterial catheter in postoperative pediatric surgery: a randomized controlled study

PubMed Central

Witkowski, Maria Carolina; de Moraes, Maria Antonieta P.; Firpo, Cora Maria F.

2013-01-01

OBJECTIVE: To compare two systems of arterial catheters maintenance in postoperative pediatric surgery using intermittent or continuous infusion of heparin solution and to analyze adverse events related to the site of catheter insertion and the volume of infused heparin solution. METHODS: Randomized control trial with 140 patients selected for continuous infusion group (CIG) and intermittent infusion group (IIG). The variables analyzed were: type of heart disease, permanence time and size of the catheter, insertion site, technique used, volume of heparin solution and adverse events. The descriptive variables were analyzed by Student's t-test and the categorical variables, by chi-square test, being significant p<0.05. RESULTS: The median age was 11 (0-22) months, and 77 (55%) were females. No significant differences between studied variables were found, except for the volume used in CIG (12.0±1.2mL/24 hours) when compared to IIG (5.3±3.5mL/24 hours) with p<0.0003. CONCLUSIONS: The continuous infusion system and the intermittent infusion of heparin solution can be used for intra-arterial catheters maintenance in postoperative pediatric surgery, regardless of patient's clinical and demographic characteristics. Adverse events up to the third postoperative day occurred similarly in both groups. However, the intermittent infusion system usage in underweight children should be considered, due to the lower volume of infused heparin solution [ClinicalTrials.gov Identifier: NCT01097031]. PMID:24473958

Influence of temperature on the CuIn1-xGaxSe2films deposited by picosecond laser ablation

NASA Astrophysics Data System (ADS)

Sima, Cornelia; Toma, Ovidiu

2017-12-01

The goal of this study is to investigate the influence of the deposition temperature on the CuIn1-xGaxSe2 (CIGS-copper indium gallium diselenide) film characteristics deposited by picosecond laser ablation method using a Nd:YVO4 laser (8 ps, 0.2 W, 50 kHz, 532 nm; 5.7 mJ/cm2; 36 × 107 pulses). The films were deposited starting from a CuIn0.7Ga0.3Se2 target, in vacuum at 3 × 10-5 Torr for 2 h, at room temperature (RT) and 100/200/300/400 °C substrate temperature; as substrate, optical glass was used. Structure, film morphology, composition and optical properties were investigated by X ray diffraction, scanning electron microscopy (energy dispersive X ray spectroscopy), spectroscopic ellipsometry and optical spectrophotometry. CIGS crystalline films have the dominant peak corresponding to (112) direction more pronounced starting with 200 °C deposition temperature. The thickness gradually decreased with temperature increasing, being 1.44 μm at RT and 0.72 μm at 400 °C; atomic composition in the case of In, Ga, Se increased after annealing, while in the case of Cu it decreased comparing with RT; refractive indices exhibited a short decreasing tendency by increasing the deposition temperature, while the optical band gap values for CuIn0.7Ga0.3Se2 laser ablated thin films increased.

Using droplet-on-demand based printing to guide self-assembly in a peptide-protein based bioink

NASA Astrophysics Data System (ADS)

Hedegaard, Clara; Collin, Estelle; Redondo-Gomez, Carlos; Nguyen, Luong T. H.; Ng, Kee Woei; Castrejon-Pita, Alfonso A.; Castrejon-Pita, J. Rafael; Mata, Alvaro

2017-11-01

Tissue engineering aims to capture details of the extracellular matrix (ECM) that stimulate tissue regeneration. Advanced biofabrication techniques have enabled structural complexity, however they are restricted by the choice of material due to stringent printing requirements, leading to a lack of nanoscale control and molecular versatility. In this project, we exploit the dynamics of droplet fluid interactions combined with the co-assembly of peptide amphiphiles (PAs) with biomolecules/proteins to develop a new approach to droplet-based biofabrication. A custom-made droplet generator was developed and used to controllably dispense droplets of PA into a protein solution resulting in gel formation within milliseconds. Taking advantage of the interfacial and inertial forces during the droplet/liquid interaction, it is possible to control the co-assembly kinetics, to give rise to aligned or disordered nanofibers, hydrogel structures of different geometries and sizes, surface topographies, and higher-ordered structures made from multiple hydrogels. The process allows multiple cell types to be spatially distributed on the outside or embedded within the ECM mimetic scaffolds, whilst exhibiting high cell viability (>88%). ERC Starting Grant (STROFUNSCAFF), FP7-PEOPLE-2013-CIG Biomorph and the Royal Society.

Development of an electronic device quality aluminum antimonide (AlSb) semiconductor for solar cell applications

DOEpatents

Sherohman, John W; Yee, Jick Hong; Combs, III, Arthur W

2014-11-11

Electronic device quality Aluminum Antimonide (AlSb)-based single crystals produced by controlled atmospheric annealing are utilized in various configurations for solar cell applications. Like that of a GaAs-based solar cell devices, the AlSb-based solar cell devices as disclosed herein provides direct conversion of solar energy to electrical power.

Key techniques for space-based solar pumped semiconductor lasers

NASA Astrophysics Data System (ADS)

He, Yang; Xiong, Sheng-jun; Liu, Xiao-long; Han, Wei-hua

2014-12-01

In space, the absence of atmospheric turbulence, absorption, dispersion and aerosol factors on laser transmission. Therefore, space-based laser has important values in satellite communication, satellite attitude controlling, space debris clearing, and long distance energy transmission, etc. On the other hand, solar energy is a kind of clean and renewable resources, the average intensity of solar irradiation on the earth is 1353W/m2, and it is even higher in space. Therefore, the space-based solar pumped lasers has attracted much research in recent years, most research focuses on solar pumped solid state lasers and solar pumped fiber lasers. The two lasing principle is based on stimulated emission of the rare earth ions such as Nd, Yb, Cr. The rare earth ions absorb light only in narrow bands. This leads to inefficient absorption of the broad-band solar spectrum, and increases the system heating load, which make the system solar to laser power conversion efficiency very low. As a solar pumped semiconductor lasers could absorb all photons with energy greater than the bandgap. Thus, solar pumped semiconductor lasers could have considerably higher efficiencies than other solar pumped lasers. Besides, solar pumped semiconductor lasers has smaller volume chip, simpler structure and better heat dissipation, it can be mounted on a small satellite platform, can compose satellite array, which can greatly improve the output power of the system, and have flexible character. This paper summarizes the research progress of space-based solar pumped semiconductor lasers, analyses of the key technologies based on several application areas, including the processing of semiconductor chip, the design of small and efficient solar condenser, and the cooling system of lasers, etc. We conclude that the solar pumped vertical cavity surface-emitting semiconductor lasers will have a wide application prospects in the space.

The Communications Toolbox for MATLAB and E0 3513 Laboratory Design

DTIC Science & Technology

1994-03-24

lengtli(quanchj)-1)) sxniejbinnuMs=bin...nums(1:6) %;.. M.asure dhe quantization noise sig-toLia.is~snr(s1 ,quansig); str --numn2str(sigjoQnois); %Plot 4...compressed quantized signal exp..comp=expmnd(quansig2,mu2,tmx(quansi2)); %use maximum signal value =nrw.ccwnp-snr(s,exp~coinp); str -num2str(sir..comp); MPot...8217) ylabelCAmplitude’) grid cig %Part 2--Observe fte differences in the spectra Program mung Laboratory 3B Key-age 3 319 %for two types of pulse-modulatWd signals

Decision Support Functions for the Retail Operations Management System.

DTIC Science & Technology

1984-09-01

0003 NUTS , PLANTERS PEANUTS CN 1 .10 Al 053200-0006 NUTS , PLANTERS MIXED CN 1.05 Al 053200-001 1 NUTS , PLANTERS CASHEWS CN 2.55 Al 053200-0052 NUTS ...PLANTERS SPANISH PEA CN 1.10 Al 053200-4877 NUTS , SMOKE HOUSE ALMONDS EA .25 A2 101120-0002 CIO, CAMEL REG PK .40 A2 101120-0004 CIO, VANTAGE REG PK .40...CANDY, TOOTSIE POP DROP EA .1450 112 033200-0006 NUTS , PLANTERS MIXED CN 1.0910 72 053200-4877 NUTS , SMOKE HOUSE ALMONDS EA .1456 44 101120-0003 CIG

Modelling of chemical degradation of blended cement-based materials by leaching cycles with Callovo-Oxfordian porewater

NASA Astrophysics Data System (ADS)

Olmeda, Javier; Henocq, Pierre; Giffaut, Eric; Grivé, Mireia

2017-06-01

The present work describes a thermodynamic model based on pore water replacement cycles to simulate the chemical evolution of blended cement (BFS + FA) by interaction with external Callovo-Oxfordian (COx) pore water. In the framework of the radioactive waste management, the characterization of the radionuclide behaviour (solubility/speciation, adsorption) in cementitious materials needs to be done for several chemical degradation states (I to IV). In particular, in the context of the deep geological radioactive waste disposal project (Cigéo), cement-based materials will be chemically evolved with time in contact with the host-rock (COx formation). The objective of this study is to provide an equilibrium solution composition for each degradation state for a CEM-V cement-based material to support the adsorption and diffusion experiments reproducing any state of degradation. Calculations have been performed at 25 °C using the geochemical code PhreeqC and an up-to-date thermodynamic database (ThermoChimie v.9.0.b) coupled to SIT approach for ionic strength correction. The model replicates experimental data with accuracy. The approach followed in this study eases the analysis of the chemical evolution in both aqueous and solid phase to obtain a fast assessment of the geochemical effects associated to an external water intrusion of variable composition on concrete structures.

Knowledge engineering for adverse drug event prevention: on the design and development of a uniform, contextualized and sustainable knowledge-based framework.

PubMed

Koutkias, Vassilis; Kilintzis, Vassilis; Stalidis, George; Lazou, Katerina; Niès, Julie; Durand-Texte, Ludovic; McNair, Peter; Beuscart, Régis; Maglaveras, Nicos

2012-06-01

The primary aim of this work was the development of a uniform, contextualized and sustainable knowledge-based framework to support adverse drug event (ADE) prevention via Clinical Decision Support Systems (CDSSs). In this regard, the employed methodology involved first the systematic analysis and formalization of the knowledge sources elaborated in the scope of this work, through which an application-specific knowledge model has been defined. The entire framework architecture has been then specified and implemented by adopting Computer Interpretable Guidelines (CIGs) as the knowledge engineering formalism for its construction. The framework integrates diverse and dynamic knowledge sources in the form of rule-based ADE signals, all under a uniform Knowledge Base (KB) structure, according to the defined knowledge model. Equally important, it employs the means to contextualize the encapsulated knowledge, in order to provide appropriate support considering the specific local environment (hospital, medical department, language, etc.), as well as the mechanisms for knowledge querying, inference, sharing, and management. In this paper, we present thoroughly the establishment of the proposed knowledge framework by presenting the employed methodology and the results obtained as regards implementation, performance and validation aspects that highlight its applicability and virtue in medication safety. Copyright © 2012 Elsevier Inc. All rights reserved.

Prediction of energy balance and utilization for solar electric cars

NASA Astrophysics Data System (ADS)

Cheng, K.; Guo, L. M.; Wang, Y. K.; Zafar, M. T.

2017-11-01

Solar irradiation and ambient temperature are characterized by region, season and time-domain, which directly affects the performance of solar energy based car system. In this paper, the model of solar electric cars used was based in Xi’an. Firstly, the meteorological data are modelled to simulate the change of solar irradiation and ambient temperature, and then the temperature change of solar cell is calculated using the thermal equilibrium relation. The above work is based on the driving resistance and solar cell power generation model, which is simulated under the varying radiation conditions in a day. The daily power generation and solar electric car cruise mileage can be predicted by calculating solar cell efficiency and power. The above theoretical approach and research results can be used in the future for solar electric car program design and optimization for the future developments.

Using the Spatial Distribution of Installers to Define Solar Photovoltaic Markets

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Shaughnessy, Eric; Nemet, Gregory F.; Darghouth, Naim

2016-09-01

Solar PV market research to date has largely relied on arbitrary jurisdictional boundaries, such as counties, to study solar PV market dynamics. This paper seeks to improve solar PV market research by developing a methodology to define solar PV markets. The methodology is based on the spatial distribution of solar PV installers. An algorithm is developed and applied to a rich dataset of solar PV installations to study the outcomes of the installer-based market definitions. The installer-based approach exhibits several desirable properties. Specifically, the higher market granularity of the installer-based approach will allow future PV market research to study themore » relationship between market dynamics and pricing with more precision.« less

GISS GCMAM Modeled Climate Responses to Total and Spectral Solar Forcing on Decadal and Centennial Time Scales

NASA Astrophysics Data System (ADS)

Wen, Guoyong; Cahalan, Robert; Rind, David; Jonas, Jeffrey; Pilewskie, Peter; Harder, Jerry

2014-05-01

We examine the influence of the SORCE (Solar Radiation and Climate Experiment) SIM (Spectral Irradiance Monitor) observed spectral solar irradiance (SSI) variations on Earth's climate. We apply two reconstructed spectral solar forcing scenarios, one SIM based, the other based on the SATIRE (Spectral And Total Irradiance REconstruction) model, as inputs to the GISS (Goddard Institute for Space Studies) GCMAM (Global Climate Middle Atmosphere Model) to examine the climate responses on decadal and centennial time scales. We show that the atmosphere has different temperature, ozone, and dynamic responses to the two solar spectral forcing scenarios, even when the variations in TSI (Total Solar Irradiance) are the same. We find that solar variations under either scenario contribute a small fraction of the observed temperature increase since the industrial revolution. The trend of global averaged surface air temperature response to the SIM-based solar forcing is 0.02 °C/century, about half of the temperature trend to the SATIRE-based SSI. However the temporal variation of the surface air temperature for the SIM-based solar forcing scenario is much larger compared to its SATIRE counterpart. Further research is required to examine TSI and SSI variations in the ascending phase of solar cycle 24, to assess their implications for the solar influence on climate.

GISS GCMAM Modeled Climate Responses to Total and Spectral Solar Forcing on Decadal and Centennial Time Scales

NASA Astrophysics Data System (ADS)

Wen, G.; Cahalan, R. F.; Rind, D. H.; Jonas, J.; Pilewskie, P.; Harder, J. W.; Krivova, N.

2014-12-01

We examine the influence of the SORCE (Solar Radiation and Climate Experiment) SIM (Spectral Irradiance Monitor) observed spectral solar irradiance (SSI) variations on Earth's climate. We apply two reconstructed spectral solar forcing scenarios, one SIM based, the other based on the SATIRE (Spectral And Total Irradiance REconstruction) model, as inputs to the GISS (Goddard Institute for Space Studies) GCMAM (Global Climate Middle Atmosphere Model) to examine the climate responses on decadal and centennial time scales. We show that the atmosphere has different temperature, ozone, and dynamic responses to the two solar spectral forcing scenarios, even when the variations in TSI (Total Solar Irradiance) are the same. We find that solar variations under either scenario contribute a small fraction of the observed temperature increase since the industrial revolution. The trend of global averaged surface air temperature response to the SIM-based solar forcing is 0.02 °C/century, about half of the temperature trend to the SATIRE-based SSI. However the temporal variation of the surface air temperature for the SIM-based solar forcing scenario is much larger compared to its SATIRE counterpart. Further research is required to examine TSI and SSI variations in the ascending phase of solar cycle 24, to assess their implications for the solar influence on climate.

Application of Ce3+ single-doped complexes as solar spectral downshifters for enhancing photoelectric conversion efficiencies of a-Si-based solar cells

NASA Astrophysics Data System (ADS)

Song, Pei; Jiang, Chun

2013-05-01

The effect on photoelectric conversion efficiency of an a-Si-based solar cell by applying a solar spectral downshifter of rare earth ion Ce3+ single-doped complexes including yttrium aluminum garnet Y3Al5O12 single crystals, nanostructured ceramics, microstructured ceramics and B2O3-SiO2-Gd2O3-BaO glass is studied. The photoluminescence excitation spectra in the region 360-460 nm convert effectively into photoluminescence emission spectra in the region 450-550 nm where a-Si-based solar cells exhibit a higher spectral response. When these Ce3+ single-doped complexes are placed on the top of an a-Si-based solar cell as precursors for solar spectral downshifting, theoretical relative photoelectric conversion efficiencies of nc-Si:H and a-Si:H solar cells approach 1.09-1.13 and 1.04-1.07, respectively, by means of AMPS-1D numerical modeling, potentially benefiting an a-Si-based solar cell with a photoelectric efficiency improvement.

Recent advances of flexible hybrid perovskite solar cells

NASA Astrophysics Data System (ADS)

Shin, Dong Hee; Heo, Jin Hyuck; Im, Sang Hyuk

2017-11-01

Recently, hybrid perovskite solar cells have attracted great interest because they can be fabricated to low cost, flexible, and highly efficient solar cells. Here, we introduced recent advances of flexible hybrid perovskite solar cells. We introduced research background of flexible perovskite solar cells in introduction part. Then we composed the main body to i) structure and properties of hybrid perovskite solar cells, ii) why flexible hybrid perovskite solar cells are important?, iii) transparent conducting oxide (TCO) based flexible hybrid perovskite solar cells, and iv) TCO-free transparent conducting electrode (TCE) based flexible hybrid perovskite solar cells. Finally, we summarized research outlook of flexible hybrid perovskite solar cells.

Laser Structuring of Thin Layers for Flexible Electronics by a Shock Wave-induced Delamination Process

NASA Astrophysics Data System (ADS)

Lorenz, Pierre; Ehrhardt, Martin; Zimmer, Klaus

The defect-free laser-assisted structuring of thin films on flexible substrates is a challenge for laser methods. However, solving this problem exhibits an outstanding potential for a pioneering development of flexible electronics. Thereby, the laser-assisted delamination method has a great application potential. At the delamination process: the localized removal of the layer is induced by a shock wave which is produced by a laser ablation process on the rear side of the substrate. In this study, the thin-film patterning process is investigated for different polymer substrates dependent on the material and laser parameters using a KrF excimer laser. The resultant structures were studied by optical microscopy and white light interferometry (WLI). The delamination process was tested at different samples (indium tin oxide (ITO) on polyethylene terephthalate (PET), epoxy-based negative photoresist (SU8) on polyimide (PI) and indium tin oxide/copper indium gallium selenide/molybdenum (ITO/CIGS/Mo) on PI.

Development of gridded solar radiation data over Belgium based on Meteosat and in-situ observations

NASA Astrophysics Data System (ADS)

Journée, Michel; Vanderveken, Gilles; Bertrand, Cédric

2013-04-01

Knowledge on solar resources is highly important for all forms of solar energy applications. With the recent development in solar-based technologies national meteorological services are faced with increasing demands for high-quality and reliable site-time specific solar resource information. Traditionally, solar radiation is observed by means of networks of meteorological stations. Costs for installation and maintenance of such networks are very high and national networks comprise only few stations. Consequently the availability of ground-based solar radiation measurements has proven to be spatially and temporally inadequate for many applications. To overcome such a limitation, a major effort has been undertaken at the Royal Meteorological Institute of Belgium (RMI) to provide the solar energy industry, the electricity sector, governments, and renewable energy organizations and institutions with the most suitable and accurate information on the solar radiation resources at the Earth's surface over the Belgian territory. Only space-based observations can deliver a global coverage of the solar irradiation impinging on horizontal surface at the ground level. Because only geostationary data allow to capture the diurnal cycle of the solar irradiance at the Earth's surface, a method that combines information from Meteosat Second Generation satellites and ground-measurement has been implemented at RMI to generate high resolution solar products over Belgium on an operational basis. Besides these new products, the annual and seasonal variability of solar energy resource was evaluated, solar radiation climate zones were defined and the recent trend in solar radiation was characterized.

Quantification of 16 polycyclic aromatic hydrocarbons in cigarette smoke condensate using stable isotope dilution liquid chromatography with atmospheric-pressure photoionization tandem mass spectrometry.

PubMed

Zhang, Xiaotao; Hou, Hongwei; Chen, Huan; Liu, Yong; Wang, An; Hu, Qingyuan

2015-09-17

A stable isotope dilution liquid chromatography with tandem mass spectrometry method for the analysis of 16 polycyclic aromatic hydrocarbons in cigarette smoke condensate was developed and validated. Compared with previously reported methods, this method has lower limits of detection (0.04-1.35 ng/cig). Additionally, the proposed method saves time, reduces the number of separation steps, and reduces the quantity of solvent needed. The new method was applied to evaluate polycyclic aromatic hydrocarbon content in 213 commercially available cigarettes in China, under the International Standardization Organization smoking regime and the Health Canadian intense smoking regime. The results showed that the total polycyclic aromatic hydrocarbon content was more than two times higher in samples from the Health Canadian intense smoking regime than in samples from the International Standardization Organization smoking regime (1189.23 vs. 2859.50 ng/cig, p<0.05). Meanwhile, the concentration of individual polycyclic aromatic hydrocarbons (and total polycyclic aromatic hydrocarbons) increased with labeled tar content in both of the tested smoking regimes. There was a positive correlation between total polycyclic aromatic hydrocarbons under the International Standardization Organization smoking regime with that under the Health Canadian intense smoking regime. The proposed liquid chromatography with tandem mass spectrometry method is satisfactory for the rapid, sensitive, and accurately quantitative evaluation of polycyclic aromatic hydrocarbon content in cigarette smoke condensate, and it can be applied to assess potential health risks from smoking. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Dissociative diffusion mechanism in vacancy-rich materials according to mass action kinetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biderman, N. J.; Sundaramoorthy, R.; Haldar, Pradeep

We conducted two sets of diffusion-reaction numerical simulations using a finite difference method (FDM) in order to investigate fast impurity diffusion via interstitial sites in vacancy-rich materials such as Cu(In,Ga)Se 2 (CIGS) and Cu 2ZnSn(S, Se) 4 (CZTSSe or CZTS) via the dissociative diffusion mechanism where the interstitial diffuser ultimately reacts with a vacancy to produce a substitutional. The first set of simulations extends the standard interstitial-limited dissociative diffusion theory to vacancy-rich material conditions where vacancies are annihilated in large amounts, introducing non-equilibrium vacancy concentration profiles. The second simulation set explores the vacancy-limited dissociative diffusion where impurity incorporation increases themore » equilibrium vacancy concentration. In addition to diffusion profiles of varying concentrations and shapes that were obtained in all simulations, some of the profiles can be fitted with the constant- and limited-source solutions of Fick’s second law despite the non-equilibrium condition induced by the interstitial-vacancy reaction. The first set of simulations reveals that the dissociative diffusion coefficient in vacancy-rich materials is inversely proportional to the initial vacancy concentration. In the second set of numerical simulations, impurity-induced changes in the vacancy concentration lead to distinctive diffusion profile shapes. The simulation results are also compared with published data of impurity diffusion in CIGS. And according to the characteristic properties of diffusion profiles from the two set of simulations, experimental detection of the dissociative diffusion mechanism in vacancy-rich materials may be possible.« less