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Sample records for a-si based solar

  1. 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.

  2. Hybrid solar cell based on a-Si/polymer flat heterojunction on flexible substrates

    NASA Astrophysics Data System (ADS)

    Olivares Vargas, A. J.; Mansurova, S.; Cosme, I.; Kosarev, A.; Ospina Ocampo, C. A.; Martinez Mateo, H. E.

    2017-08-01

    In this work, we present the results of investigation of thin film hybrid organic-inorganic photovoltaic structures based on flat heterojunction hydrogenated silicon (a-Si:H) and poly(3,4 ethylene dioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) fabricated on polyethylene naphthalate (PEN). Different thicknesses of transparent AL doped Zn:O (AZO) electrodes have been tested on PEN substrate and studied by atomic force microscopy (AFM). The AZO films on PEN substrate were statistically processed to obtain surface morphological characteristics, such as root mean square roughness RQ, skewness SK and kurtosis KU. Performance characteristics of fabricated photovoltaic structures have been measured and analyzed for different thicknesses of the transparent electrodes under standard illumination (AM 1.5 I0= 100mW/cm2). Structures on flexible substrates show reproducible performance characteristic as their glass substrate counterpart with values of JSC= 6 mA/cm2, VOC= 0.535 V, FF= 43 % and PCE= 1.41%.

  3. Study of the Staebler-Wronski degradation effect in a-Si:H based p-i-n solar cell

    NASA Technical Reports Server (NTRS)

    Naseem, H. A.; Brown, W. D.; Ang, S. S.

    1993-01-01

    Conversion of solar energy into electricity using environmentally safe and clean photovoltaic methods to supplement the ever increasing energy needs has been a cherished goal of many scientists and engineers around the world. Photovoltaic solar cells on the other hand, have been the power source for satellites ever since their introduction in the early sixties. For widespread terrestrial applications, however, the cost of photovoltaic systems must be reduced considerably. Much progress has been made in the recent past towards developing economically viable terrestrial systems, and the future looks highly promising. Thin film solar cells offer cost reductions mainly from their low processing cost, low material cost, and choice of low cost substrates. These are also very attractive for space applications because of their high power densities (power produced per kilogram of solar cell pay load) and high radiation resistance. Amorphous silicon based solar cells are amongst the top candidates for economically viable terrestrial and space based power generation. Despite very low federal funding during the eighties, amorphous silicon solar cell efficiencies have continually been improved - from a low 3 percent to over 13 percent now. Further improvements have been made by the use of multi-junction tandem solar cells. Efficiencies close to 15 percent have been achieved in several labs. In order to be competitive with fossil fuel generated electricity, it is believed that module efficiency of 15 percent or cell efficiency of 20 percent is required. Thus, further improvements in cell performance is imperative. One major problem that was discovered almost 15 years ago in amorphous silicon devices is the well known Staebler-Wronski Effect. Efficiency of amorphous silicon solar cells was found to degrade upon exposure to sunlight. Until now their is no consensus among the scientists on the mechanism for this degradation. Efficiency may degrade anywhere from 10 percent to almost

  4. Optoelectrical modeling of solar cells based on c-Si/a-Si:H nanowire array: focus on the electrical transport in between the nanowires.

    PubMed

    Levtchenko, Alexandra; Le Gall, Sylvain; Lachaume, Raphaël; Michallon, Jérôme; Collin, Stéphane; Alvarez, José; Djebbour, Zakaria; Kleider, Jean-Paul

    2018-06-22

    By coupling optical and electrical modeling, we have investigated the photovoltaic performances of p-i-n radial nanowires array based on crystalline p-type silicon (c-Si) core/hydrogenated amorphous silicon (a-Si:H) shell. By varying either the doping concentration of the c-Si core, or back contact work function we can separate and highlight the contribution to the cell's performance of the nanowires themselves (the radial cell) from the interspace between the nanowires (the planar cell). We show that the build-in potential (V bi ) in the radial and planar cells strongly depends on the doping of c-Si core and the work function of the back contact respectively. Consequently, the solar cell's performance is degraded if either the doping concentration of the c-Si core, or/and the work function of the back contact is too low. By inserting a thin (p) a-Si:H layer between both core/absorber and back contact/absorber, the performance of the solar cell can be improved by partly fixing the V bi at both interfaces due to strong electrostatic screening effect. Depositing such a buffer layer playing the role of an electrostatic screen for charge carriers is a suggested way of enhancing the performance of solar cells based on radial p-i-n or n-i-p nanowire array.

  5. Optoelectrical modeling of solar cells based on c-Si/a-Si:H nanowire array: focus on the electrical transport in between the nanowires

    NASA Astrophysics Data System (ADS)

    Levtchenko, Alexandra; Le Gall, Sylvain; Lachaume, Raphaël; Michallon, Jérôme; Collin, Stéphane; Alvarez, José; Djebbour, Zakaria; Kleider, Jean-Paul

    2018-06-01

    By coupling optical and electrical modeling, we have investigated the photovoltaic performances of p-i-n radial nanowires array based on crystalline p-type silicon (c-Si) core/hydrogenated amorphous silicon (a-Si:H) shell. By varying either the doping concentration of the c-Si core, or back contact work function we can separate and highlight the contribution to the cell’s performance of the nanowires themselves (the radial cell) from the interspace between the nanowires (the planar cell). We show that the build-in potential (V bi) in the radial and planar cells strongly depends on the doping of c-Si core and the work function of the back contact respectively. Consequently, the solar cell’s performance is degraded if either the doping concentration of the c-Si core, or/and the work function of the back contact is too low. By inserting a thin (p) a-Si:H layer between both core/absorber and back contact/absorber, the performance of the solar cell can be improved by partly fixing the V bi at both interfaces due to strong electrostatic screening effect. Depositing such a buffer layer playing the role of an electrostatic screen for charge carriers is a suggested way of enhancing the performance of solar cells based on radial p-i-n or n-i-p nanowire array.

  6. High Efficiency Thin Film CdTe and a-Si Based Solar Cells: Final Technical Report, 4 March 1998--15 October 2001

    SciTech Connect

    Compaan, A. D.; Deng, X.; Bohn, R. G.

    2003-10-01

    This is the final report covering about 42 months of this subcontract for research on high-efficiency CdTe-based thin-film solar cells and on high-efficiency a-Si-based thin-film solar cells. Phases I and II have been extensively covered in two Annual Reports. For this Final Report, highlights of the first two Phases will be provided and then detail will be given on the last year and a half of Phase III. The effort on CdTe-based materials is led by Prof. Compaan and emphasizes the use of sputter deposition of the semiconductor layers in the fabrication of CdS/CdTe cells. The effort on high-efficiency a-Simore » materials is led by Prof. Deng and emphasizes plasma-enhanced chemical vapor deposition for cell fabrication with major efforts on triple-junction devices.« less

  7. Evidence of significant down-conversion in a Si-based solar cell using CuInS2/ZnS core shell quantum dots

    NASA Astrophysics Data System (ADS)

    Gardelis, Spiros; Nassiopoulou, Androula G.

    2014-05-01

    We report on the increase of up to 37.5% in conversion efficiency of a Si-based solar cell after deposition of light-emitting Cd-free, CuInS2/ZnS core shell quantum dots on the active area of the cell due to the combined effect of down-conversion and the anti- reflecting property of the dots. We clearly distinguished the effect of down-conversion from anti-reflection and estimated an enhancement of up to 10.5% in the conversion efficiency due to down-conversion.

  8. High performance a-Si solar cells and new fabrication methods for a-Si solar cells

    NASA Astrophysics Data System (ADS)

    Nakano, S.; Kuwano, Y.; Ohnishi, M.

    1986-12-01

    The super chamber, a separated UHV reaction-chamber system has been developed. A conversion efficiency of 11.7% was obtained for an a-Si solar cell using a high-quality i-layer deposited by the super chamber, and a p-layer fabricated by a photo-CVD method. As a new material, amorphous superlattice-structure films were fabricated by the photo-CVD method for the first time. Superlattice structure p-layer a-Si solar cells were fabricated, and a conversion efficiency of 10.5% was obtained. For the fabrication of integrated type a-Si solar cell modules, a laser pattering method was investigated. A thermal analysis of the multilayer structure was done. It was confirmed that selective scribing for a-Si, TCO and metal film is possible by controlling the laser power density. Recently developed a-Si solar power generation systems and a-Si solar cell roofing tiles are also described.

  9. Parameter variation of the one-diode model of a-Si and a- Si/μc-Si solar cells for modeling light-induced degradation

    NASA Astrophysics Data System (ADS)

    Weicht, J. A.; Hamelmann, F. U.; Behrens, G.

    2014-11-01

    For analyzing the long-term behavior of thin film a-Si/μc-Si photovoltaic modules, it is important to observe the light-induced degradation (LID) in dependence of the temperature for the parameters of the one-diode model for solar cells. According to the IEC 61646 standard, the impact of LID on module parameters of these thin film cells is determined at a constant temperature of 50°C with an irradiation of 1000 W/m2 at open circuit conditions. Previous papers examined the LID of thin film a-Si cells with different temperatures and some others are about a-Si/μc-Si. In these previous papers not all parameters of the one-diode model are examined. We observed the serial resistance (Rs), parallel resistance (Rp), short circuit current (Isc), open circuit voltage (Uoc), the maximum power point (MPP: Umpp, Impp and Pmpp) and the diode factor (n). Since the main reason for the LID of silicon-based thin films is the Staebler Wronski effect in the a-Si part of the cell, the temperature dependence of the healing of defects for all parameters of the one-diode model is also taken into account. We are also measuring modules with different kind of transparent conductive oxides: In a-Si thin film solar cells fluorine-doped tin oxide (FTO) is used and for thin film solar cells of a-Si/μc-Si boron- doped zinc oxide is used. In our work we describe an approach for transferring the parameters of a one-diode model for tandem thin film solar cells into the one-diode model for each part of the solar cell. The measurement of degradation and regeneration at higher temperatures is the necessary base for optimization of the different silicon-based thin films in warm hot climate.

  10. a-Si:H/SiNW shell/core for SiNW solar cell applications

    PubMed Central

    2013-01-01

    Vertically aligned silicon nanowires have been synthesized by the chemical etching of silicon wafers. The influence of a hydrogenated amorphous silicon (a-Si:H) layer (shell) on top of a silicon nanowire (SiNW) solar cell has been investigated. The optical properties of a-Si:H/SiNWs and SiNWs are examined in terms of optical reflection and absorption properties. In the presence of the a-Si:H shell, 5.2% reflection ratio in the spectral range (250 to 1,000 nm) is achieved with a superior absorption property with an average over 87% of the incident light. In addition, the characteristics of the solar cell have been significantly improved, which exhibits higher open-circuit voltage, short-circuit current, and efficiency by more than 15%, 12%, and 37%, respectively, compared with planar SiNW solar cells. Based on the current–voltage measurements and morphology results, we show that the a-Si:H shell can passivate the defects generated by wet etching processes. PMID:24195734

  11. Trade-offs of the opto-electrical properties of a-Si:H solar cells based on MOCVD BZO films.

    PubMed

    Chen, Ze; Zhang, Xiao-dan; Liang, Jun-hui; Fang, Jia; Liang, Xue-jiao; Sun, Jian; Zhang, De-kun; Chen, Xin-liang; Huang, Qian; Zhao, Ying

    2015-01-07

    Boron-doped zinc oxide (BZO) films, deposited by metal-organic chemical vapor deposition (MOCVD), have been widely used as front electrodes in thin-film solar cells due to their native pyramidal surface structure, which results in efficient light trapping. This light trapping effect can enhance the short-circuit current density (Jsc) of solar cells. However, nanocracks or voids in the silicon active layer may form when the surface morphology of the BZO is too sharp; this usually leads to degraded electrical properties of the cells, such as open-circuit voltage (Voc) and the fill factor (FF), which in turn decreases efficiency (Eff) [Bailat et al., Photovoltaic Energy Conversion, Conference Record of the 2006 IEEE 4th World Conference on. IEEE, 2006, vol. 2, pp. 1533-1536]. In this paper, an etching and coating method was proposed to modify the sharp "pyramids" on the surface of the BZO films. As a result, an evident enhancement was achieved for these modified, BZO-based cells' Voc, FF, and Eff, although the Jsc exhibited a small decrease. In order to increase the Jsc and maintain the improved electrical properties (Voc, FF) of the cell, a thin BZO coating, deposited by MOCVD, was introduced to coat the sputtering-treated BZO film. Finally, we optimized the trade-off among the Voc, FF, and Jsc, that is, we identified a regime with an increase of the Jsc as well as a further improvement of the other electrical properties.

  12. Optimization of intrinsic layer thickness, dopant layer thickness and concentration for a-SiC/a-SiGe multilayer solar cell efficiency performance using Silvaco software

    NASA Astrophysics Data System (ADS)

    Yuan, Wong Wei; Natashah Norizan, Mohd; Salwani Mohamad, Ili; Jamalullail, Nurnaeimah; Hidayah Saad, Nor

    2017-11-01

    Solar cell is expanding as green renewable alternative to conventional fossil fuel electricity generation, but compared to other land-used electrical generators, it is a comparative beginner. Many applications covered by solar cells starting from low power mobile devices, terrestrial, satellites and many more. To date, the highest efficiency solar cell is given by GaAs based multilayer solar cell. However, this material is very expensive in fabrication and material costs compared to silicon which is cheaper due to the abundance of supply. Thus, this research is devoted to develop multilayer solar cell by combining two different layers of P-I-N structures with silicon carbide and silicon germanium. This research focused on optimising the intrinsic layer thickness, p-doped layer thickness and concentration, n-doped layer thickness and concentration in achieving the highest efficiency. As a result, both single layer a-SiC and a-SiGe showed positive efficiency improvement with the record of 27.19% and 9.07% respectively via parametric optimization. The optimized parameters is then applied on both SiC and SiGe P-I-N layers and resulted the convincing efficiency of 33.80%.

  13. Origin of Photovoltage Enhancement via Interfacial Modification with Silver Nanoparticles Embedded in an a-SiC:H p-Type Layer in a-Si:H Solar Cells.

    PubMed

    Li, Tiantian; Zhang, Qixing; Ni, Jian; Huang, Qian; Zhang, Dekun; Li, Baozhang; Wei, Changchun; Yan, Baojie; Zhao, Ying; Zhang, Xiaodan

    2017-03-29

    We used silver nanoparticles (Ag-NPs) embedded in the p-type semiconductor layer of hydrogenated amorphous silicon (a-Si:H) solar cells in the Schottky barrier contact design to modify the interface between aluminum-doped ZnO (ZnO:Al, AZO) and p-type hydrogenated amorphous silicon carbide (p-a-SiC:H) without plasmonic absorption. The high work function of the Ag-NPs provided a good channel for the transport of photogenerated holes. A p-type nanocrystalline SiC:H layer was used to compensate for the real surface defects and voids on the surface of Ag-NPs to reduce recombination at the AZO/p-type layer interface, which then enhanced the photovoltage of single-junction a-Si:H solar cells to values as high as 1.01 V. The Ag-NPs were around 10 nm in diameter and thermally stable in the p-type a-SiC:H film at the solar-cell process temperature. We will also show that a wide range of photovoltages between 1.01 and 2.89 V could be obtained with single-, double-, and triple-junction solar cells based on the single-junction a-Si:H solar cells with tunable high photovoltage. These solar cells are suitable photocathodes for solar water-splitting applications.

  14. Optimization of imprintable nanostructured a-Si solar cells: FDTD study.

    PubMed

    Fisker, Christian; Pedersen, Thomas Garm

    2013-03-11

    We present a finite-difference time-domain (FDTD) study of an amorphous silicon (a-Si) thin film solar cell, with nano scale patterns on the substrate surface. The patterns, based on the geometry of anisotropically etched silicon gratings, are optimized with respect to the period and anti-reflection (AR) coating thickness for maximal absorption in the range of the solar spectrum. The structure is shown to increase the cell efficiency by 10.2% compared to a similar flat solar cell with an optimized AR coating thickness. An increased back reflection can be obtained with a 50 nm zinc oxide layer on the back reflector, which gives an additional efficiency increase, leading to a total of 14.9%. In addition, the patterned cells are shown to be up to 3.8% more efficient than an optimized textured reference cell based on the Asahi U-type glass surface. The effects of variations of the optimized solar cell structure due to the manufacturing process are investigated, and shown to be negligible for variations below ±10%.

  15. Analytical solution for haze values of aluminium-induced texture (AIT) glass superstrates for a-Si:H solar cells.

    PubMed

    Sahraei, Nasim; Forberich, Karen; Venkataraj, Selvaraj; Aberle, Armin G; Peters, Marius

    2014-01-13

    Light scattering at randomly textured interfaces is essential to improve the absorption of thin-film silicon solar cells. Aluminium-induced texture (AIT) glass provides suitable scattering for amorphous silicon (a-Si:H) solar cells. The scattering properties of textured surfaces are usually characterised by two properties: the angularly resolved intensity distribution and the haze. However, we find that the commonly used haze equations cannot accurately describe the experimentally observed spectral dependence of the haze of AIT glass. This is particularly the case for surface morphologies with a large rms roughness and small lateral feature sizes. In this paper we present an improved method for haze calculation, based on the power spectral density (PSD) function of the randomly textured surface. To better reproduce the measured haze characteristics, we suggest two improvements: i) inclusion of the average lateral feature size of the textured surface into the haze calculation, and ii) considering the opening angle of the haze measurement. We show that with these two improvements an accurate prediction of the haze of AIT glass is possible. Furthermore, we use the new equation to define optimum morphology parameters for AIT glass to be used for a-Si:H solar cell applications. The autocorrelation length is identified as the critical parameter. For the investigated a-Si:H solar cells, the optimum autocorrelation length is shown to be 320 nm.

  16. Further insight on recombination losses in the intrinsic layer of a-Si:H solar cells using computer modeling tools

    NASA Astrophysics Data System (ADS)

    Rubinelli, Francisco A.; Ramirez, Helena; Ruiz, Carlos M.; Schmidt, Javier A.

    2017-05-01

    Recombination losses of a-Si:H based p-i-n solar cells in the annealed state are analyzed with device computer modeling. Under AM1.5 illumination, the recombination rate in the intrinsic layer is shown to be controlled by a combination of losses through defect and tail states. The influence of the defect concentration on the characteristic parameters of a solar cell is analyzed. The impact on the light current-voltage characteristic curve of adopting very low free carrier mobilities and a high density of states at the band edge is explored under red and AM1.5 illumination. The distribution of trapped charge, electric field, and recombination loses inside the intrinsic layer is examined, and their influence on the solar cell performance is discussed. Solar cells with intrinsic layers deposited with and without hydrogen dilution are examined. It is found that the photocurrent at -2 V is not always a good approximation of the saturated reverse-bias photocurrent in a-Si:H p-i-n solar cells at room temperature. The importance of using realistic electrical parameters in solar cell simulations is emphasized.

  17. Development of New a-Si/c-Si Heterojunction Solar Cells: ACJ-HIT (Artificially Constructed Junction-Heterojunction with Intrinsic Thin-Layer)

    NASA Astrophysics Data System (ADS)

    Tanaka, Makoto; Taguchi, Mikio; Matsuyama, Takao; Sawada, Toru; Tsuda, Shinya; Nakano, Shoichi; Hanafusa, Hiroshi; Kuwano, Yukinori

    1992-11-01

    A new type of a-Si/c-Si heterojunction solar cell, called the HIT (Heterojunction with Intrinsic Thin-layer) solar cell, has been developed based on ACJ (Artificially Constructed Junction) technology. A conversion efficiency of more than 18% has been achieved, which is the highest ever value for solar cells in which the junction was fabricated at a low temperature (<200°C).

  18. Mechanical Properties of ZTO, ITO, and a-Si:H Multilayer Films for Flexible Thin Film Solar Cells

    PubMed Central

    Hengst, Claudia; Menzel, Siegfried B; Rane, Gayatri K; Smirnov, Vladimir; Wilken, Karen; Leszczynska, Barbara; Fischer, Dustin; Prager, Nicole

    2017-01-01

    The behavior of bi- and trilayer coating systems for flexible a-Si:H based solar cells consisting of a barrier, an electrode, and an absorption layer is studied under mechanical load. First, the film morphology, stress, Young’s modulus, and crack onset strain (COS) were analyzed for single film coatings of various thickness on polyethylene terephthalate (PET) substrates. In order to demonstrate the role of the microstructure of a single film on the mechanical behavior of the whole multilayer coating, two sets of InSnOx (indium tin oxide, ITO) conductive coatings were prepared. Whereas a characteristic grain–subgrain structure was observed in ITO-1 films, grain growth was suppressed in ITO-2 films. ITO-1 bilayer coatings showed two-step failure under tensile load with cracks propagating along the ITO-1/a-Si:H-interface, whereas channeling cracks in comparable bi- and trilayers based on amorphous ITO-2 run through all constituent layers. A two-step failure is preferable from an application point of view, as it may lead to only a degradation of the performance instead of the ultimate failure of the device. Hence, the results demonstrate the importance of a fine-tuning of film microstructure not only for excellent electrical properties, but also for a high mechanical performance of flexible devices (e.g., a-Si:H based solar cells) during fabrication in a roll-to-roll process or under service. PMID:28772609

  19. Mechanical Properties of ZTO, ITO, and a-Si:H Multilayer Films for Flexible Thin Film Solar Cells.

    PubMed

    Hengst, Claudia; Menzel, Siegfried B; Rane, Gayatri K; Smirnov, Vladimir; Wilken, Karen; Leszczynska, Barbara; Fischer, Dustin; Prager, Nicole

    2017-03-01

    The behavior of bi- and trilayer coating systems for flexible a-Si:H based solar cells consisting of a barrier, an electrode, and an absorption layer is studied under mechanical load. First, the film morphology, stress, Young's modulus, and crack onset strain (COS) were analyzed for single film coatings of various thickness on polyethylene terephthalate (PET) substrates. In order to demonstrate the role of the microstructure of a single film on the mechanical behavior of the whole multilayer coating, two sets of InSnOx (indium tin oxide, ITO) conductive coatings were prepared. Whereas a characteristic grain-subgrain structure was observed in ITO-1 films, grain growth was suppressed in ITO-2 films. ITO-1 bilayer coatings showed two-step failure under tensile load with cracks propagating along the ITO-1/a-Si:H-interface, whereas channeling cracks in comparable bi- and trilayers based on amorphous ITO-2 run through all constituent layers. A two-step failure is preferable from an application point of view, as it may lead to only a degradation of the performance instead of the ultimate failure of the device. Hence, the results demonstrate the importance of a fine-tuning of film microstructure not only for excellent electrical properties, but also for a high mechanical performance of flexible devices (e.g., a-Si:H based solar cells) during fabrication in a roll-to-roll process or under service.

  20. Influence of Deposition Pressure on the Properties of Round Pyramid Textured a-Si:H Solar Cells for Maglev.

    PubMed

    Lee, Jaehyeong; Choi, Wonseok; Lee, Kyuil; Lee, Daedong; Kang, Hyunil

    2016-05-01

    HIT (Heterojunction with Intrinsic Thin-layer) photovoltaic cells is one of the highest efficiencies in the commercial solar cells. The pyramid texturization for reducing surface reflectance of HIT solar cells silicon wafers is widely used. For the low leakage current and high shunt of solar cells, the intrinsic amorphous silicon (a-Si:H) on substrate must be uniformly thick of pyramid structure. However, it is difficult to control the thickness in the traditional pyramid texturing process. Thus, we textured the intrinsic a-Si:H thin films with the round pyramidal structure by using HNO3, HF, and CH3COOH solution. The characteristics of round pyramid a-Si:H solar cells deposited at pressure of 500, 1000, 1500, and 2000 mTorr by PECVD (Plasma Enhanced Chemical Vapor Deposition) was investigated. The lifetime, open circuit voltage, fill factor and efficiency of a-Si:H solar cells were investigated with respect to various deposition pressure.

  1. Simulation of light-induced degradation of μc-Si in a-Si/μc-Si tandem solar cells by the diode equivalent circuit

    NASA Astrophysics Data System (ADS)

    Weicht, J. A.; Hamelmann, F. U.; Behrens, G.

    2016-02-01

    Silicon-based thin film tandem solar cells consist of one amorphous (a-Si) and one microcrystalline (μc-Si) silicon solar cell. The Staebler - Wronski effect describes the light- induced degradation and temperature-dependent healing of defects of silicon-based solar thin film cells. The solar cell degradation depends strongly on operation temperature. Until now, only the light-induced degradation (LID) of the amorphous layer was examined in a-Si/μc-Si solar cells. The LID is also observed in pc-Si single function solar cells. In our work we show the influence of the light-induced degradation of the μc-Si layer on the diode equivalent circuit. The current-voltage-curves (I-V-curves) for the initial state of a-Si/pc-Si modules are measured. Afterwards the cells are degraded under controlled conditions at constant temperature and constant irradiation. At fixed times the modules are measured at standard test conditions (STC) (AM1.5, 25°C cell temperature, 1000 W/m2) for controlling the status of LID. After the degradation the modules are annealed at dark conditions for several hours at 120°C. After the annealing the dangling bonds in the amorphous layer are healed, while the degradation of the pc-Si is still present, because the healing of defects in pc-Si solar cells needs longer time or higher temperatures. The solar cells are measured again at STC. With this laboratory measured I-V-curves we are able to separate the values of the diode model: series Rs and parallel resistance Rp, saturation current Is and diode factor n.

  2. Influnce of exposure with Xe radiation on heterojunction solar cell a-SiC/c-Si studied by impedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Perný, M.; Šály, V.; Packa, J.; Mikolášek, M.; Váry, M.; Huran, J.; Hrubčín, L.; Skuratov, V. A.; Arbet, J.

    2017-04-01

    The photovoltaic efficiency of heterostructures a-SiC/c-Si may be the same or even better in comparison with conventional silicon structures when suitable adjustment of technological parameters is realized. The main advantage of heterojunction formed amorphous SiC thin film and crystalline silicon compared to standard crystalline solar cell lies in high build-in voltage and thus a high open-circuit voltage. Solar cells can be exposed to various influences of hard environment. A deterioration of properties of heterostructures (a-SiC/c-Si) due to irradiation is examined in our paper using impedance spectroscopy method. Xe ions induced damage is reflected in changes of proposed AC equivalent circuit elements. AC equivalent circuit was proposed and verified using numerical simulations. Impedance spectra were also measured at different DC bias voltages due to a more detailed understanding correlation between Xe ions induced damage and transport phenomenon in the heterostructure.

  3. Using high haze (> 90%) light-trapping film to enhance the efficiency of a-Si:H solar cells

    NASA Astrophysics Data System (ADS)

    Chu, Wei-Ping; Lin, Jian-Shian; Lin, Tien-Chai; Tsai, Yu-Sheng; Kuo, Chen-Wei; Chung, Ming-Hua; Hsieh, Tsung-Eong; Liu, Lung-Chang; Juang, Fuh-Shyang; Chen, Nien-Po

    2012-07-01

    The high haze light-trapping (LT) film offers enhanced scattering of light and is applied to a-Si:H solar cells. UV glue was spin coated on glass, and then the LT pattern was imprinted. Finally, a UV lamp was used to cure the UV glue on the glass. The LT film effectively increased the Haze ratio of glass and decreased the reflectance of a-Si:H solar cells. Therefore, the photon path length was increased to obtain maximum absorption by the absorber layer. High Haze LT film is able to enhance short circuit current density and efficiency of the device, as partial composite film generates broader scattering light, thereby causing shorter wave length light to be absorbed by the P layer so that the short circuit current density decreases. In case of lab-made a-Si:H thin film solar cells with v-shaped LT films, superior optoelectronic performances have been found (Voc = 0.74 V, Jsc = 15.62 mA/cm2, F.F. = 70%, and η = 8.09%). We observed ~ 35% enhancement of the short-circuit current density and ~ 31% enhancement of the conversion efficiency.

  4. Nondestructive characterization of textured a-Si:H/c-Si heterojunction solar cell structures with nanometer-scale a-Si:H and In2O3:Sn layers by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Matsuki, Nobuyuki; Fujiwara, Hiroyuki

    2013-07-01

    Nanometer-scale hydrogenated amorphous silicon (a-Si:H) layers formed on crystalline silicon (c-Si) with pyramid-shaped textures have been characterized by spectroscopic ellipsometry (SE) using a tilt angle measurement configuration, in an attempt to establish a nondestructive method for the structural characterization of the a-Si:H/c-Si heterojunction solar cells. By applying an a-Si:H dielectric function model developed recently, the thickness and SiH2 content of the a-Si:H layer have been determined even on the textured substrates. Furthermore, from the SE analysis incorporating the Drude model, the carrier properties of the In2O3:Sn layers in the textured solar-cell structure have been characterized.

  5. Nanoimprinted backside reflectors for a-Si:H thin-film solar cells: critical role of absorber front textures.

    PubMed

    Tsao, Yao-Chung; Fisker, Christian; Pedersen, Thomas Garm

    2014-05-05

    The development of optimal backside reflectors (BSRs) is crucial for future low cost and high efficiency silicon (Si) thin-film solar cells. In this work, nanostructured polymer substrates with aluminum coatings intended as BSRs were produced by positive and negative nanoimprint lithography (NIL) techniques, and hydrogenated amorphous silicon (a-Si:H) was deposited hereon as absorbing layers. The relationship between optical properties and geometry of front textures was studied by combining experimental reflectance spectra and theoretical simulations. It was found that a significant height variation on front textures plays a critical role for light-trapping enhancement in solar cell applications. As a part of sample preparation, a transfer NIL process was developed to overcome the problem of low heat deflection temperature of polymer substrates during solar cell fabrication.

  6. Numerical Optimization of a Bifacial Bi-Glass Thin-Film a-Si:H Solar Cell for Higher Conversion Efficiency

    NASA Astrophysics Data System (ADS)

    Berrian, Djaber; Fathi, Mohamed; Kechouane, Mohamed

    2018-02-01

    Bifacial solar cells that maximize the energy output per a square meter have become a new fashion in the field of photovoltaic cells. However, the application of thin-film material on bifacial solar cells, viz., thin-film amorphous hydrogenated silicon ( a- Si:H), is extremely rare. Therefore, this paper presents the optimization and influence of the band gap, thickness and doping on the performance of a glass/glass thin-film a- Si:H ( n- i- p) bifacial solar cell, using a computer-aided simulation tool, Automat for simulation of hetero-structures (AFORS-HET). It is worth mentioning that the thickness and the band gap of the i-layer are the key parameters in achieving higher efficiency and hence it has to be handled carefully during the fabrication process. Furthermore, an efficient thin-film a- Si:H bifacial solar cell requires thinner and heavily doped n and p emitter layers. On the other hand, the band gap of the p-layer showed a dramatic reduction of the efficiency at 2.3 eV. Moreover, a high bifaciality factor of more than 92% is attained, and top efficiency of 10.9% is revealed under p side illumination. These optimizations demonstrate significant enhancements of the recent experimental work on thin-film a- Si:H bifacial solar cells and would also be useful for future experimental investigations on an efficient a- Si:H thin-film bifacial solar cell.

  7. A Si IV/O IV Electron Density Diagnostic for the Analysis of IRIS Solar Spectra

    NASA Astrophysics Data System (ADS)

    Young, P. R.; Keenan, F. P.; Milligan, R. O.; Peter, H.

    2018-04-01

    Solar spectra of ultraviolet bursts and flare ribbons from the Interface Region Imaging Spectrograph (IRIS) have suggested high electron densities of > {10}12 cm‑3 at transition region temperatures of 0.1 MK, based on large intensity ratios of Si IV λ1402.77 to O IV λ1401.16. In this work, a rare observation of the weak O IV λ1343.51 line is reported from an X-class flare that peaked at 21:41 UT on 2014 October 24. This line is used to develop a theoretical prediction of the Si IV λ1402.77 to O IV λ1401.16 ratio as a function of density that is recommended to be used in the high-density regime. The method makes use of new pressure-dependent ionization fractions that take account of the suppression of dielectronic recombination at high densities. It is applied to two sequences of flare kernel observations from the October 24 flare. The first shows densities that vary between 3× {10}12 and 3× {10}13 cm‑3 over a seven-minute period, while the second location shows stable density values of around 2× {10}12 cm‑3 over a three-minute period.

  8. Solar Water Splitting Utilizing a SiC Photocathode, a BiVO4 Photoanode, and a Perovskite Solar Cell.

    PubMed

    Iwase, Akihide; Kudo, Akihiko; Numata, Youhei; Ikegami, Masashi; Miyasaka, Tsutomu; Ichikawa, Naoto; Kato, Masashi; Hashimoto, Hideki; Inoue, Haruo; Ishitani, Osamu; Tamiaki, Hitoshi

    2017-11-23

    We have successfully demonstrated solar water splitting using a newly fabricated photoelectrochemical system with a Pt-loaded SiC photocathode, a CoO x -loaded BiVO 4 photoanode, and a perovskite solar cell. Detection of the evolved H 2 and O 2 with a 100 % Faradaic efficiency indicates that the observed photocurrent was used for water splitting. The solar-to-hydrogen (STH) efficiency was 0.55 % under no additional bias conditions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Binary synaptic connections based on memory switching in a-Si:H for artificial neural networks

    NASA Technical Reports Server (NTRS)

    Thakoor, A. P.; Lamb, J. L.; Moopenn, A.; Khanna, S. K.

    1987-01-01

    A scheme for nonvolatile associative electronic memory storage with high information storage density is proposed which is based on neural network models and which uses a matrix of two-terminal passive interconnections (synapses). It is noted that the massive parallelism in the architecture would require the ON state of a synaptic connection to be unusually weak (highly resistive). Memory switching using a-Si:H along with ballast resistors patterned from amorphous Ge-metal alloys is investigated for a binary programmable read only memory matrix. The fabrication of a 1600 synapse test array of uniform connection strengths and a-Si:H switching elements is discussed.

  10. Amorphous silicon solar cells

    NASA Astrophysics Data System (ADS)

    Takahashi, K.; Konagai, M.

    The fabrication, performance, and applications of a-Si solar cells are discussed, summarizing the results of recent experimental investigations and trial installations. Topics examined include the fundamental principles and design strategies of solar power installations; the characteristics of monocrystalline-Si solar cells; techniques for reducing the cost of solar cells; independent, linked, and hybrid solar power systems; proposed satellite solar power systems; and the use of solar cells in consumer appliances. Consideration is given to the history of a-Si, a-Si fabrication techniques, quality criteria for a-Si films, solar cells based on a-Si, and techniques for increasing the efficiency and lowering the cost of a-Si solar cells. Graphs, diagrams, drawings, and black-and-white and color photographs are provided.

  11. The role of high work-function metallic nanodots on the performance of a-Si:H solar cells: offering ohmic contact to light trapping.

    PubMed

    Kim, Jeehwan; Abou-Kandil, Ahmed; Fogel, Keith; Hovel, Harold; Sadana, Devendra K

    2010-12-28

    Addition of carbon into p-type "window" layers in hydrogenated amorphous silicon (a-Si:H) solar cells enhances short circuit currents and open circuit voltages by a great deal. However, a-Si:H solar cells with high carbon-doped "window" layers exhibit poor fill factors due to a Schottky barrier-like impedance at the interface between a-SiC:H windows and transparent conducting oxides (TCO), although they show maximized short circuit currents and open circuit voltages. The impedance is caused by an increasing mismatch between the work function of TCO and that of p-type a-SiC:H. Applying ultrathin high-work-function metals at the interface between the two materials results in an effective lowering of the work function mismatch and a consequent ohmic behavior. If the metal layer is sufficiently thin, then it forms nanodots rather than a continuous layer which provides light-scattering effect. We demonstrate 31% efficiency enhancement by using high-work-function materials for engineering the work function at the key interfaces to raise fill factors as well as photocurrents. The use of metallic interface layers in this work is a clear contrast to previous work where attempts were made to enhance the photocurrent using plasmonic metal nanodots on the solar cell surface.

  12. Evolution of a Native Oxide Layer at the a-Si:H/c-Si Interface and Its Influence on a Silicon Heterojunction Solar Cell.

    PubMed

    Liu, Wenzhu; Meng, Fanying; Zhang, Xiaoyu; Liu, Zhengxin

    2015-12-09

    The interface microstructure of a silicon heterojunction (SHJ) solar cell was investigated. We found an ultrathin native oxide layer (NOL) with a thickness of several angstroms was formed on the crystalline silicon (c-Si) surface in a very short time (∼30 s) after being etched by HF solution. Although the NOL had a loose structure with defects that are detrimental for surface passivation, it acted as a barrier to restrain the epitaxial growth of hydrogenated amorphous silicon (a-Si:H) during the plasma-enhanced chemical vapor deposition (PECVD). The microstructure change of the NOL during the PECVD deposition of a-Si:H layers with different conditions and under different H2 plasma treatments were systemically investigated in detail. When a brief H2 plasma was applied to treat the a-Si:H layer after the PECVD deposition, interstitial oxygen and small-size SiO2 precipitates were transformed to hydrogenated amorphous silicon suboxide alloy (a-SiO(x):H, x ∼ 1.5). In the meantime, the interface defect density was reduced by about 50%, and the parameters of the SHJ solar cell were improved due to the post H2 plasma treatment.

  13. Enhancement of a-Si:H solar cell efficiency by Y2O3 : Yb3+, Er3+ near infrared spectral upconverter

    NASA Astrophysics Data System (ADS)

    Markose, Kurias K.; Anjana, R.; Subha, P. P.; Antony, Aldrin; Jayaraj, M. K.

    2016-09-01

    The optical properties of Yb3+/Er3+ doped Y2O3 upconversion phosphor and the enhancement of efficiency of a-Si:H solar cell on incorporation of upconverter are investigated. The Y2O3 host material has high corrosion resistance, thermal stability, chemical stability, low toxicity and relatively low phonon energy (≈ 500 cm-1). Y2O3:Yb3+ (x %): Er3+ (y %) upconversion nanophosphors with different dopant concentrations were synthesized via simple hydrothermal method followed by a heat treatment at 1200°C for 12 hrs. Highly crystalline, quasi-spherical, body centered cubic Y2O3 structure was obtained. The structure, phase and morphology of the nanocrystals were determined using x-ray diffraction and SEM. Following pumping at 980 nm two dominant emission bands were observed at about 550 nm(green) and 660 nm(red), corresponding to 2H11/2, 4S3/2 -> 4I15/2 and 4F9/2 -> 4I15/2 transitions respectively. The dependence of emission intensity on pump power shows that the mechanism involved is two photon absorption. The upconversion phosphor along with a binder is coupled behind the a-Si:H solar cell which absorbs transmitted sub-band-gap photons and emits back the upconverted visible light which can be absorbed by the solar cell. Under suitable intensity of illumination the solar cell short circuit current is found to be increased on adding the upconversion layer.

  14. Optical bias selector based on a multilayer a-SiC:H optical filter

    NASA Astrophysics Data System (ADS)

    Vieira, M.; Vieira, M. A.; Louro, P.

    2017-08-01

    In this paper we present a MUX/DEMUX device based on a multilayer a-SiC:H optical filter that requires nearultraviolet steady state optical switches to select desired wavelengths in the visible range. Spectral response and transmittance measurements are presented and show the feasibility of tailoring the wavelength and bandwidth of a polychromatic mixture of different wavelengths. The selector filter is realized by using a two terminal double pi'n/pin a-SiC:H photodetector. Five visible communication channels are transmitted together, each one with a specific bit sequence. The combined optical signal is analyzed by reading out the photocurrent, under near-UV front steady state background. Data shows that 25 current levels are detected and corresponds to the thirty-two on/off possible states. The proximity of the magnitude of consecutive levels causes occasional errors in the decoded information. To minimize the errors, four parity bit are generated and stored along with the data word. The parity of the word is checked after reading the word to detect and correct the transmitted data. Results show that the background works as a selector in the visible range, shifting the sensor sensitivity and together with the parity check bits allows the identification and decoding of the different input channels. A transmission capability of 60 kbps using the generated codeword was achieved. An optoeletronic model gives insight on the system physics.

  15. High Temperature Capacitive Pressure Sensor Employing a SiC Based Ring Oscillator

    NASA Technical Reports Server (NTRS)

    Meredith, Roger D.; Neudeck, Philip G.; Ponchak, George E.; Beheim, Glenn M.; Scardelletti, Maximilian; Jordan, Jennifer L.; Chen, Liang-Yu; Spry, David J.; Krawowski, Michael J.; Hunter, Gary W.

    2011-01-01

    In an effort to develop harsh environment electronic and sensor technologies for aircraft engine safety and monitoring, we have used capacitive-based pressure sensors to shift the frequency of a SiC-electronics-based oscillator to produce a pressure-indicating signal that can be readily transmitted, e.g. wirelessly, to a receiver located in a more benign environment. Our efforts target 500 C, a temperature well above normal operating conditions of commercial circuits but within areas of interest in aerospace engines, deep mining applications and for future missions to the Venus atmosphere. This paper reports for the first time a ring oscillator circuit integrated with a capacitive pressure sensor, both operating at 500 C. This demonstration represents a significant step towards a wireless pressure sensor that can operate at 500 C and confirms the viability of 500 C electronic sensor systems.

  16. Polyimide based amorphous silicon solar modules

    NASA Technical Reports Server (NTRS)

    Jeffrey, Frank R.; Grimmer, Derrick P.; Martens, Steven A.; Abudagga, Khaled; Thomas, Michael L.; Noak, Max

    1993-01-01

    Requirements for space power are increasingly emphasizing lower costs and higher specific powers. This results from new fiscal constraints, higher power requirements for larger applications, and the evolution toward longer distance missions such as a Lunar or Mars base. The polyimide based a-Si modules described are being developed to meet these needs. The modules consist of tandem a-Si solar cell material deposited directly on a roll of polyimide. A laser scribing/printing process subdivides the deposition into discrete cell strips which are series connected to produce the required voltage without cutting the polymer backing. The result is a large, monolithic, blanket type module approximately 30 cm wide and variable in length depending on demand. Current production modules have a specific power slightly over 500 W/Kg with room for significant improvement. Costs for the full blanket modules range from $30/Watt to $150/Watt depending on quantity and engineering requirements. Work to date focused on the modules themselves and adjusting them for the AMO spectrum. Work is needed yet to insure that the modules are suitable for the space environment.

  17. Impedance spectroscopy of heterojunction solar cell a-SiC/c-Si with ITO antireflection film investigated at different temperatures

    NASA Astrophysics Data System (ADS)

    Šály, V.; Perný, M.; Janíček, F.; Huran, J.; Mikolášek, M.; Packa, J.

    2017-04-01

    Progressive smart photovoltaic technologies including heterostructures a-SiC/c-Si with ITO antireflection film are one of the prospective replacements of conventional photovoltaic silicon technology. Our paper is focused on the investigation of heterostructures a-SiC/c-Si provided with a layer of ITO (indium oxide/tin oxide 90/10 wt.%) which acts as a passivating and antireflection coating. Prepared photovoltaic cell structure was investigated at various temperatures and the influence of temperature on its operation was searched. The investigation of the dynamic properties of heterojunction PV cells was carried out using impedance spectroscopy. The equivalent AC circuit which approximates the measured impedance data was proposed. Assessment of the influence of the temperature on the operation of prepared heterostructure was carried out by analysis of the temperature dependence of AC equivalent circuit elements.

  18. Study of p-type and intrinsic materials for amorphous silicon based solar cells

    NASA Astrophysics Data System (ADS)

    Du, Wenhui

    This dissertation summarizes the research work on the investigation and optimization of high efficiency hydrogenated amorphous silicon (a-Si:H) based thin film n-i-p single-junction and multi-junction solar cells, deposited using radio frequency (RF) and very high frequency (VHF) plasma enhanced chemical vapor deposition (PECVD) techniques. The fabrication and characterization of high quality p-type and intrinsic materials for a-Si:H based solar cells have been systematically and intensively studied. Hydrogen dilution, substrate temperature, gas flow rate, RF- or VHF-power density, and films deposition time have been optimized to obtain "on-the-edge" materials. To understand the material structure of the silicon p-layer providing a high Voc a-Si:H solar cell, hydrogenated amorphous, protocrystalline, and nanocrystalline silicon p-layers have been prepared using RF-PECVD and characterized by Raman spectroscopy and high resolution transmission electronic microscopy (HRTEM). It was found that the optimum Si:H p-layer for n-i-p a-Si:H solar cells is composed of fine-grained nanocrystals with crystallite sizes in the range of 3-5 nm embedded in an amorphous network. Using the optimized p-layer, an a-Si:H single-junction solar cell with a very high Voc value of 1.042 V and a FF value of 0.74 has been obtained. a-Si:H, a-SiGe:H and nc-Si:H i-layers have been prepared using RF- and VHF-PECVD techniques and monitored by different optical and electrical characterizations. Single-junction a-Si:H, a-SiGe and nc-Si:H cells have been developed and optimized. Intermediate bandgap a-SiGe:H solar cells achieved efficiencies over 12.5%. On the basis of optimized component cells, we achieved a-Si:Hla-SiGe:H tandem solar cells with efficiencies of ˜12.9% and a-Si:H/a-SiGe:H/a-SiGe:H triple-junction cells with efficiencies of ˜12.03%. VHF-PECVD technique was used to increase the deposition rates of the narrow bandgap materials. The deposition rate for a-SiGe:H i-layer attained 9 A

  19. Fabrication and testing of mis solar cells on a-Si:F:H. Final report, September 15, 1979-September 15, 1980

    SciTech Connect

    Han, M. K.; Anderson, W. A.

    1980-11-03

    Fabrication techniques and improved a-Si:H film processing have been achieved to produce a short circuit current density of 7.5 mA/cm/sup 2/ and open circuit voltage of 740 mV on large area (2cm/sup 2/) a-Si cells by the deposition of an inexpensive semitransparent metal (Cr) as a top electrode on a N-I-P structure. This corresponds to a 2% efficiency using AMl illumination. A V/sub oc/ of 830 mV and fill factor of 0.54 have also been separately obtained. A relatively simple and inexpensive deposition technique using a one pumpdown vacuum system, Al grid and thin metal film structure have been appliedmore » to reduce the cost of a-Si:H cell fabrication. A SEM study of a-Si film quality shows the substrate texture to greatly influence the film morphology. This in turn serves to influence the uniformity of photovoltaic response on completed solar cells. The studies of optical transmittance of various thin metal films promote the utilization of Cr and Cu as a top electrode. Dark and illuminated I-V characteristics show that current conduction mechanisms and recombination pheonomena are not the same under dark and illuminated conditions. Furthermore, spectral response analysis and reverse illuminated saturation current under different illumination levels show photoconductivity and collection efficiency to be a function of illumination level. Significant differences in spectral response are observed when comparing P-I-N, N-I-P and I-N structures. A Schottky barrier lowering effect is proposed to explain some spectral response data. The importance of the top junction region to carrier collection is also discussed.« less

  20. Amorphous and crystalline silicon based heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Schüttauf, J. A.

    2011-10-01

    saturation by H, whereas the decrease at higher temperatures is caused by H effusion. For intrinsic/n-type a-Si:H layer stacks, a record minority carrier lifetime of 13.3 ms is obtained. In contrast, for intrinsic/p-type a-Si:H layer stacks, a deterioration in passivation is observed over the whole temperature range, due to the asymmetric Fermi-level dependent defect formation enthalpy in n- and p-type a-Si:H. Comparing the lifetime values and trends for the different layer stacks to the performance of the corresponding cells, it is observed that the intrinsic/p-layer stack is limiting device performance. Based on these findings, the solar cells were prepared in a modified order, reaching an efficiency of 16.7% (VOC = 681 mV), versus 15.8% (VOC = 659 mV) in the ‘standard’ order. Finally, transparent conductive oxide (TCO) layers are studied for application into solar cells. It is observed that both types of TCO deposition have no significant influence on the passivation properties of standard a-Si:H layer stacks forming the emitter structure in the used SHJ cells. On flat wafers, a conversion efficiency of 16.7% has been obtained when ITO is used as TCO, versus an efficiency of 16.3% for ZnO:Al; slightly lower due to increased electrical losses.

  1. Investigation of baseline measurement resolution of a Si plate-based extrinsic Fabry-Perot interferometer

    NASA Astrophysics Data System (ADS)

    Ushakov, Nikolai; Liokumovich, Leonid

    2014-05-01

    Measurement of a wafer thickness is of a great value for fabrication and interrogation of MEMS/MOEMS devices, as well as conventional optical fiber sensors. In the current paper we investigate the abilities of the wavelength-scanning interferometry techniques for registering the baseline of an extrinsic fiber Fabry-Perot interferometer (EFPI) with the cavity formed by the two sides of a silicon plate. In order to enhance the resolution, an improved signal processing algorithm was developed. Various experiments, including contact and non-contact measurement of a silicon wafer thickness were performed, with the achieved resolutions from 10 to 20 pm. This enables one to use the described approach for high-precision measurement of geometric parameters of micro electro (electro-optic) mechanical systems for their characterization, utilization in sensing tasks and fabrication control. An ability of a Si plate-based EFPI interrogated by the developed technique to capture temperature variations of about 4 mK was demonstrated.

  2. Spectroscopic Ellipsometry Studies of Thin Film a-Si:H/nc-Si:H Micromorph Solar Cell Fabrication in the p-i-n Superstrate Configuration

    NASA Astrophysics Data System (ADS)

    Huang, Zhiquan

    Spectroscopic ellipsometry (SE) is a non-invasive optical probe that is capable of accurately and precisely measuring the structure of thin films, such as their thicknesses and void volume fractions, and in addition their optical properties, typically defined by the index of refraction and extinction coefficient spectra. Because multichannel detection systems integrated into SE instrumentation have been available for some time now, the data acquisition time possible for complete SE spectra has been reduced significantly. As a result, real time spectroscopic ellipsometry (RTSE) has become feasible for monitoring thin film nucleation and growth during the deposition of thin films as well as during their removal in processes of thin film etching. Also because of the reduced acquisition time, mapping SE is possible by mounting an SE instrument with a multichannel detector onto a mechanical translation stage. Such an SE system is capable of mapping the thin film structure and its optical properties over the substrate area, and thereby evaluating the spatial uniformity of the component layers. In thin film photovoltaics, such structural and optical property measurements mapped over the substrate area can be applied to guide device optimization by correlating small area device performance with the associated local properties. In this thesis, a detailed ex-situ SE study of hydrogenated amorphous silicon (a-Si:H) thin films and solar cells prepared by plasma enhanced chemical vapor deposition (PECVD) has been presented. An SE analysis procedure with step-by-step error minimization has been applied to obtain accurate measures of the structural and optical properties of the component layers of the solar cells. Growth evolution diagrams were developed as functions of the deposition parameters in PECVD for both p-type and n-type layers to characterize the regimes of accumulated thickness over which a-Si:H, hydrogenated nanocrystalline silicon (nc-Si:H) and mixed phase (a

  3. Growth of KOH etched AZO nanorods and investigation of its back scattering effect in thin film a-Si solar cell

    NASA Astrophysics Data System (ADS)

    Sharma, Jayasree Roy; Mitra, Suchismita; Ghosh, Hemanta; Das, Gourab; Bose, Sukanta; Mandal, Sourav; Mukhopadhyay, Sumita; Saha, Hiranmay; Barua, A. K.

    2018-02-01

    In order to increase the stabilized efficiencies of thin film silicon (TFS) solar cells it is necessary to use better light management techniques. Texturization by etching of sputtered aluminum doped zinc oxide (Al:ZnO or AZO) films has opened up a variety of promises to optimize light trapping schemes. RF sputtered AZO film has been etched by potassium hydroxide (KOH). A systematic study of etching conditions such as etchant concentration, etching time, temperature management etc. have been performed in search of improved electrical and optical performances of the films. The change in etching conditions has exhibited a noticeable effect on the structure of AZO films for which the light trapping effect differs. After optimizing the etching conditions, nanorods have been found on the substrate. Hence, nanorods have been developed only by chemical etching, rather than the conventional development method (hydrothermal method, sol-gel method, electrolysis method etc.). The optimized etched substrate has 82% transmittance, moderate haze in the visible range and sheet resistance ∼13 (Ω/□). The developed nanorods (optimized etched substrate) provide better light trapping within the cell as the optical path length has been increased by using the nanorods. This provides an effect on carrier collection as well as the efficiency in a-Si solar cells. Finite difference time domain (FDTD) simulations have been performed to observe the light trapping by AZO nanorods formed on sputtered AZO films. For a p-i-n solar cell developed on AZO nanorods coated with sputtered AZO films, it has been found through simulations that, the incident light is back scattered into the absorbing layer, leading to an increase in photogenerated current and hence higher efficiency. It has been found that, the light that passes through the nanorods is not getting absorbed and maximum amount of light is back scattered towards the solar cell.

  4. Criteria for improved open-circuit voltage in a-Si :H(N)/c-Si(P) front heterojunction with intrinsic thin layer solar cells

    NASA Astrophysics Data System (ADS)

    Nath, Madhumita; Chatterjee, P.; Damon-Lacoste, J.; Roca i Cabarrocas, P.

    2008-02-01

    Hydrog enated amorphous/crystalline silicon "heterojunction with intrinsic thin layer (HIT)" solar cells have gained popularity after it was demonstrated by Sanyo that they can achieve stable conversion efficiencies, as high as crystalline silicon (c-Si) cells, but where the cost may be reduced with the help of amorphous silicon (a-Si:H) low temperature deposition technology. In this article, we study N-a-Si :H/P-c-Si front HIT structures, where light enters through the N-a-Si :H layer. The aim is to examine ways of improving the open-circuit voltage, using computer modeling in conjunction with experiments. We also assess under which conditions such improvements in Voc actually occur. Modeling indicates that for a density of states Nss⩾1013cm-2 on the surface of the P-c-Si wafer facing the emitter layer, Voc is entirely limited by this parameter and is lower than 0.5V. We also learn that it is possible to increase the Voc to ˜0.73V by reducing this defect density to ˜1010cm-2, by reducing the surface recombination speed of the electrons at the back P-c-Si/aluminum contact (SnL), and by improving the lifetime of the carriers (τ ) in the P-c-Si wafer to ˜5ms. Modeling further indicates that when τ ⩽0.1ms, the sensitivity of Voc to SnL vanishes, as very few back-diffusing electrons can reach the back contact. Improvements in Voc by decreasing both the defect density on the surface of the P-c-Si wafer facing the emitter layer and SnL have been achieved in practice by (a) improved passivation thanks to a thin intrinsic polymorphous silicon layer deposited on the c-Si wafer (instead of a-Si :H) and (b) using localized aluminum and back surface field layers to attain a lower SnL. Experimentally, a Voc of 0.675V has already been attained. Simulations indicate that the lifetime of carriers inside the P-c-Si wafer of these cells is ˜366μs and needs to be improved to achieve a higher Voc.

  5. Light trapping in a-Si/c-Si heterojunction solar cells by embedded ITO nanoparticles at rear surface

    NASA Astrophysics Data System (ADS)

    Dhar, Sukanta; Mandal, Sourav; Mitra, Suchismita; Ghosh, Hemanta; Mukherjee, Sampad; Banerjee, Chandan; Saha, Hiranmoy; Barua, A. K.

    2017-12-01

    The advantages of the amorphous silicon (a-Si)/crystalline silicon (c-Si) hetero junction technology are low temperature (<200 °C) processing and fewer process steps to fabricate the device. In this work, we used indium tin oxide (ITO) nanoparticles embedded in amorphous silicon material at the rear side of the crystalline wafer. The nanoparticles were embedded in silicon to have higher scattering efficiency, as has been established by simulation studies. It has been shown that significant photocurrent enhancements (32.8 mA cm-2 to 35.1 mA cm-2) are achieved because of high scattering and coupling efficiency of the embedded nanoparticles into the silicon device, leading to an increase in efficiency from 13.74% to 15.22%. In addition, we have observed a small increase in open circuit voltage. This may be due to the surface passivation during the ITO nanoparticle formation with hydrogen plasma treatment. We also support our experimental results by simulation, with the help of a commercial finite-difference time-domain (FDTD) software solution.

  6. Progress in a-SiOx:H thin film solar cells with patterned MgF2 dielectric for top cell of multi-junction system

    NASA Astrophysics Data System (ADS)

    Kang, Dong-Won; Sichanugrist, Porponth; Konagai, Makoto

    2016-07-01

    We successfully designed and experimentally demonstrated an application of patterned MgF2 dielectric material at rear Al-doped ZnO (AZO)/Ag interface in thin film amorphous silicon oxide ( a-SiOx:H) solar cells. When it was realized in practical device process, MgF2 coverage with patterned morphology was employed to allow for current flow between the AZO and Ag against highly resistive MgF2 material. On the basis of the suggested structure, we found an improvement in quantum efficiency of the solar cells with the patterned MgF2. In addition, an enhancement of open circuit voltage ( V oc ) and fill factor ( FF) was observed. A remarkable increase in shunt resistance of the cells with the MgF2 would possibly indicate that the highly resistive MgF2 layer can partly suppress physical shunting across top and bottom electrodes caused by very thin absorber thickness of only 100 nm. The approach showed that our best-performing device revealed an essential improvement in conversion efficiency from 7.83 to 8.01% with achieving markedly high V oc (1.013 V) and FF (0.729). [Figure not available: see fulltext.

  7. Performance of a SiPM based semi-monolithic scintillator PET detector.

    PubMed

    Zhang, Xianming; Wang, Xiaohui; Ren, Ning; Kuang, Zhonghua; Deng, Xinhan; Fu, Xin; Wu, San; Sang, Ziru; Hu, Zhanli; Liang, Dong; Liu, Xin; Zheng, Hairong; Yang, Yongfeng

    2017-09-21

    A depth encoding PET detector module using semi-monolithic scintillation crystal single-ended readout by a SiPM array was built and its performance was measured. The semi-monolithic scintillator detector consists of 11 polished LYSO slices measuring 1  ×  11.6  ×  10 mm 3 . The slices are glued together with enhanced specular reflector (ESR) in between and outside of the slices. The bottom surface of the slices is coupled to a 4  ×  4 SiPM array with a 1 mm light guide and silicon grease between them. No reflector is used on the top surface and two sides of the slices to reduce the scintillation photon reflection. The signals of the 4  ×  4 SiPM array are grouped along rows and columns separately into eight signals. Four SiPM column signals are used to identify the slices according to the center of the gravity of the scintillation photon distribution in the pixelated direction. Four SiPM row signals are used to estimate the y (monolithic direction) and z (depth of interaction) positions according to the center of the gravity and the width of the scintillation photon distribution in the monolithic direction, respectively. The detector was measured with 1 mm sampling interval in both the y and z directions with electronic collimation by using a 0.25 mm diameter 22 Na point source and a 1  ×  1  ×  20 mm 3 LYSO crystal detector. An average slice based energy resolution of 14.9% was obtained. All slices of 1 mm thick were clearly resolved and a detector with even thinner slices could be used. The y positions calculated with the center of gravity method are different for interactions happening at the same y, but different z positions due to depth dependent edge effects. The least-square minimization and the maximum likelihood positioning algorithms were developed and both methods improved the spatial resolution at the edges of the detector as compared with the center of gravity method. A mean absolute

  8. Performance of a SiPM based semi-monolithic scintillator PET detector

    NASA Astrophysics Data System (ADS)

    Zhang, Xianming; Wang, Xiaohui; Ren, Ning; Kuang, Zhonghua; Deng, Xinhan; Fu, Xin; Wu, San; Sang, Ziru; Hu, Zhanli; Liang, Dong; Liu, Xin; Zheng, Hairong; Yang, Yongfeng

    2017-10-01

    A depth encoding PET detector module using semi-monolithic scintillation crystal single-ended readout by a SiPM array was built and its performance was measured. The semi-monolithic scintillator detector consists of 11 polished LYSO slices measuring 1  ×  11.6  ×  10 mm3. The slices are glued together with enhanced specular reflector (ESR) in between and outside of the slices. The bottom surface of the slices is coupled to a 4  ×  4 SiPM array with a 1 mm light guide and silicon grease between them. No reflector is used on the top surface and two sides of the slices to reduce the scintillation photon reflection. The signals of the 4  ×  4 SiPM array are grouped along rows and columns separately into eight signals. Four SiPM column signals are used to identify the slices according to the center of the gravity of the scintillation photon distribution in the pixelated direction. Four SiPM row signals are used to estimate the y (monolithic direction) and z (depth of interaction) positions according to the center of the gravity and the width of the scintillation photon distribution in the monolithic direction, respectively. The detector was measured with 1 mm sampling interval in both the y and z directions with electronic collimation by using a 0.25 mm diameter 22Na point source and a 1  ×  1  ×  20 mm3 LYSO crystal detector. An average slice based energy resolution of 14.9% was obtained. All slices of 1 mm thick were clearly resolved and a detector with even thinner slices could be used. The y positions calculated with the center of gravity method are different for interactions happening at the same y, but different z positions due to depth dependent edge effects. The least-square minimization and the maximum likelihood positioning algorithms were developed and both methods improved the spatial resolution at the edges of the detector as compared with the center of gravity method. A mean absolute error

  9. Results of some initial space qualification testing on triple junction a-Si and CuInSe2 thin film solar cells

    NASA Technical Reports Server (NTRS)

    Mueller, Robert L.; Anspaugh, Bruce E.

    1993-01-01

    A series of environmental tests were completed on one type of triple junction a-Si and two types of CuInSe2 thin film solar cells. The environmental tests include electron irradiation at energies of 0.7, 1.0, and 2.0 MeV, proton irradiation at energies of 0.115, 0.24, 0.3, 0.5, 1.0, and 3.0 MeV, post-irradiation annealing at temperatures between 20 C and 60 C, long term exposure to air mass zero (AM0) photons, measurement of the cells as a function of temperature and illumination intensity, and contact pull strength tests. As expected, the cells are very resistant to electron and proton irradiation. However, when a selected cell type is exposed to low energy protons designed to penetrate to the junction region, there is evidence of more significant damage. A significant amount of recovery was observed after annealing in several of the cells. However, it is not permanent and durable, but merely a temporary restoration, later nullified with additional irradiation. Contact pull strengths measured on the triple junction a-Si cells averaged 667 grams, and pull strengths measured on the Boeing CuInSe2 cells averaged 880 grams. Significant degradation of all cell types was observed after exposure to a 580 hour photon degradation test, regardless of whether the cells had been unirradiated or irradiated (electrons or protons). Although one cell from one manufacturer lost approximately 60 percent of its power after the photon test, several other cells from this manufacturer did not degrade at all.

  10. Development of a Si-PM based alpha camera for plutonium detection in nuclear fuel facilities

    NASA Astrophysics Data System (ADS)

    Morishita, Yuki; Yamamoto, Seiichi; Izaki, Kenji; Kaneko, Junichi H.; Toi, Kohei; Tsubota, Youichi

    2014-05-01

    Alpha particles are monitored for detecting nuclear fuel material (i.e., plutonium and uranium) at nuclear fuel facilities. Currently, for monitoring the airborne contamination of nuclear fuel, only energy information measured by Si-semiconductor detectors is used to distinguish nuclear fuel material from radon daughters. In some cases, however, such distinguishing is difficult when the radon concentration is high. In addition, a Si-semiconductor detector is generally sensitive to noise. In this study, we developed a new alpha-particle imaging system by combining a Si-PM array, which is insensitive to noise, with a Ce-doped Gd3Al2Ga3O12(GAGG) scintillator, and evaluated our developed system's fundamental performance. The scintillator was 0.1-mm thick, and the light guide was 3.0 mm thick. An 241Am source was used for all the measurements. We evaluated the spatial resolution by taking an image of a resolution chart. A 1.6 lp/mm slit was clearly resolved, and the spatial resolution was estimated to be less than 0.6-mm FWHM. The energy resolution was 13% FWHM. A slight distortion was observed in the image, and the uniformity near its center was within ±24%. We conclude that our developed alpha-particle imaging system is promising for plutonium detection at nuclear fuel facilities.

  11. Design, fabrication and characterization of an a-Si:H-based UV detector for sunburn applications

    NASA Astrophysics Data System (ADS)

    Bayat, Khadijeh; Vygranenko, Yuriy; Sazonov, Andrei; Farrokh-Baroughi, Mahdi

    2006-12-01

    A thin-film a-Si:H pin detector was developed for selective detection of UVA (320-400 nm) radiation. In order for the fabrication technology to be transferable onto flexible substrates, all of the processing steps were conducted at temperatures less than 125 °C. The measured saturation current as low as 2 pA cm-2 and the ideality factor of 1.47 show that the pin diodes have a good quality i-layer as well as p-i and n-i interfaces. The film thicknesses were optimized to suppress the detector sensitivity in the visible spectral range, and the peak of spectral response was observed at 410 nm. The selectivity estimated from the ratio of the photocurrent generated by UVA absorption to the total photocurrent is 21%.

  12. Scattering matrix analysis for evaluating the photocurrent in hydrogenated-amorphous-silicon-based thin film solar cells.

    PubMed

    Shin, Myunghun; Lee, Seong Hyun; Lim, Jung Wook; Yun, Sun Jin

    2014-11-01

    A scattering matrix (S-matrix) analysis method was developed for evaluating hydrogenated amorphous silicon (a-Si:H)-based thin film solar cells. In this approach, light wave vectors A and B represent the incoming and outgoing behaviors of the incident solar light, respectively, in terms of coherent wave and incoherent intensity components. The S-matrix determines the relation between A and B according to optical effects such as reflection and transmission, as described by the Fresnel equations, scattering at the boundary surfaces, or scattering within the propagation medium, as described by the Beer-Lambert law and the change in the phase of the propagating light wave. This matrix can be used to evaluate the behavior of angle-incident coherent and incoherent light simultaneously, and takes into account not only the light scattering process at material boundaries (haze effects) but also nonlinear optical processes within the material. The optical parameters in the S-matrix were determined by modeling both a 2%-gallium-doped zinc oxide transparent conducting oxide and germanium-compounded a-Si:H (a-SiGe:H). Using the S-matrix equations, the photocurrent for an a-Si:H/a-SiGe:H tandem cell and the optical loss in semitransparent a-Si:H solar cells for use in building-integrated photovoltaic applications were analyzed. The developed S-matrix method can also be used as a general analysis tool for various thin film solar cells.

  13. Measured and Simulated Dark J-V Characteristics of a-Si:H Single Junction p-i-n Solar Cells Irradiated with 40 keV Electrons

    NASA Technical Reports Server (NTRS)

    Lord, Kenneth; Woodyard, James R.

    2002-01-01

    The effect of 40 keV electron irradiation on a-Si:H p-i-n single-junction solar cells was investigated using measured and simulated dark J-V characteristics. EPRI-AMPS and PC-1D simulators were explored for use in the studies. The EPRI-AMPS simulator was employed and simulator parameters selected to produce agreement with measured J-V characteristics. Three current mechanisms were evident in the measured dark J-V characteristics after electron irradiation, namely, injection, shunting and a term of the form CV(sup m). Using a single discrete defect state level at the center of the band gap, good agreement was achieved between measured and simulated J-V characteristics in the forward-bias voltage region where the dark current density was dominated by injection. The current mechanism of the form CV(sup m) was removed by annealing for two hours at 140 C. Subsequent irradiation restored the CV(sup m) current mechanism and it was removed by a second anneal. Some evidence of the CV(sup m) term is present in device simulations with a higher level of discrete density of states located at the center of the bandgap.

  14. Identification of thyroid tumor cell vulnerabilities through a siRNA-based functional screening.

    PubMed

    Anania, Maria; Gasparri, Fabio; Cetti, Elena; Fraietta, Ivan; Todoerti, Katia; Miranda, Claudia; Mazzoni, Mara; Re, Claudia; Colombo, Riccardo; Ukmar, Giorgio; Camisasca, Stefano; Pagliardini, Sonia; Pierotti, Marco; Neri, Antonino; Galvani, Arturo; Greco, Angela

    2015-10-27

    The incidence of thyroid carcinoma is rapidly increasing. Although generally associated with good prognosis, a fraction of thyroid tumors are not cured by standard therapy and progress to aggressive forms for which no effective treatments are currently available. In order to identify novel therapeutic targets for thyroid carcinoma, we focused on the discovery of genes essential for sustaining the oncogenic phenotype of thyroid tumor cells, but not required to the same degree for the viability of normal cells (non-oncogene addiction paradigm). We screened a siRNA oligonucleotide library targeting the human druggable genome in thyroid cancer BCPAP cell line in comparison with immortalized normal human thyrocytes (Nthy-ori 3-1). We identified a panel of hit genes whose silencing interferes with the growth of tumor cells, while sparing that of normal ones. Further analysis of three selected hit genes, namely Cyclin D1, MASTL and COPZ1, showed that they represent common vulnerabilities for thyroid tumor cells, as their inhibition reduced the viability of several thyroid tumor cell lines, regardless the histotype or oncogenic lesion. This work identified non-oncogenes essential for sustaining the phenotype of thyroid tumor cells, but not of normal cells, thus suggesting that they might represent promising targets for new therapeutic strategies.

  15. A SiC MOSFET Based Inverter for Wireless Power Transfer Applications

    SciTech Connect

    Onar, Omer C; Chinthavali, Madhu Sudhan; Campbell, Steven L

    2014-01-01

    In a wireless power transfer (WPT) system, efficiency of the power conversion stages is crucial so that the WPT technology can compete with the conventional conductive charging systems. Since there are 5 or 6 power conversion stages, each stage needs to be as efficient as possible. SiC inverters are crucial in this case; they can handle high frequency operation and they can operate at relatively higher temperatures resulting in reduces cost and size for the cooling components. This study presents the detailed power module design, development, and fabrication of a SiC inverter. The proposed inverter has been tested at threemore » center frequencies that are considered for the WPT standardization. Performance of the inverter at the same target power transfer level is analyzed along with the other system components. In addition, another SiC inverter has been built in authors laboratory by using the ORNL designed and developed SiC modules. It is shown that the inverter with ORNL packaged SiC modules performs simular to that of the inverter having commercially available SiC modules.« less

  16. Low-cost low-power uncooled a-Si-based micro infrared camera for unattended ground sensor applications

    NASA Astrophysics Data System (ADS)

    Schimert, Thomas R.; Ratcliff, David D.; Brady, John F., III; Ropson, Steven J.; Gooch, Roland W.; Ritchey, Bobbi; McCardel, P.; Rachels, K.; Wand, Marty; Weinstein, M.; Wynn, John

    1999-07-01

    Low power and low cost are primary requirements for an imaging infrared camera used in unattended ground sensor arrays. In this paper, an amorphous silicon (a-Si) microbolometer-based uncooled infrared camera technology offering a low cost, low power solution to infrared surveillance for UGS applications is presented. A 15 X 31 micro infrared camera (MIRC) has been demonstrated which exhibits an f/1 noise equivalent temperature difference sensitivity approximately 67 mK. This sensitivity has been achieved without the use of a thermoelectric cooler for array temperature stabilization thereby significantly reducing the power requirements. The chopperless camera is capable of operating from snapshot mode (1 Hz) to video frame rate (30 Hz). Power consumption of 0.4 W without display, and 0.75 W with display, respectively, has been demonstrated at 30 Hz operation. The 15 X 31 camera demonstrated exhibits a 35 mm camera form factor employing a low cost f/1 singlet optic and LED display, as well as low cost vacuum packaging. A larger 120 X 160 version of the MIRC is also in development and will be discussed. The 120 X 160 MIRC exhibits a substantially smaller form factor and incorporates all the low cost, low power features demonstrated in the 15 X 31 MIRC prototype. In this paper, a-Si microbolometer technology for the MIRC will be presented. Also, the key features and performance parameters of the MIRC are presented.

  17. Coherent manipulation of a Si/SiGe-based singlet-triplet qubit

    NASA Astrophysics Data System (ADS)

    Gyure, Mark

    2012-02-01

    Electrically defined silicon-based qubits are expected to show improved quantum memory characteristics in comparison to GaAs-based devices due to reduced hyperfine interactions with nuclear spins. Silicon-based qubit devices have proved more challenging to build than their GaAs-based counterparts, but recently several groups have reported substantial progress in single-qubit initialization, measurement, and coherent operation. We report [1] coherent control of electron spins in two coupled quantum dots in an undoped Si/SiGe heterostructure, forming two levels of a singlet-triplet qubit. We measure a nuclei-induced T2^* of 360 ns, an increase over similar measurements in GaAs-based quantum dots by nearly two orders of magnitude. We also describe the results from detailed modeling of our materials and devices that show this value for T2^* is consistent with theoretical expectations for our estimated dot sizes and a natural abundance of ^29Si. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressly or implied, of the United States Department of Defense or the U.S. Government. Approved for public release, distribution unlimited.[4pt] [1] B. M. Maune et al., ``Coherent Singlet-Triplet Oscillations in a Silicon-based Double Quantum Dot,'' accepted by Nature.

  18. High Temperature Performance of a SiC MESFET Based Oscillator

    NASA Technical Reports Server (NTRS)

    Schwartz, Zachary D.; Ponchak, George E.

    2005-01-01

    A hybrid, UHF-Band differential oscillator based on 10 w SiC RF Power Metal Semiconductor Field Effect Transistor (MESFET) has been designed, fabricated and characterized through 475 C. Circuit is fabricated on an alumina substrate with thin film spiral inductors, chip capacitors, chip resistors, and wire bonds for all crossovers and interconnectors. The oscillator delivers 15.7 dBm at 515 MHz into a 50 Ohm load at 125 C with a DC to RF conversion efficiency of 2,8%. After tuning the load impedance, the oscillator delivers 18.8 dBm at 610 MHz at 200 C with a DC to RF conversion efficiency of 5.8%. Finally, by tuning the load and bias conditions, the oscillator delivers 4.9 dBm at 453 MHz at 475 C.

  19. A SiPM based real time dosimeter for radiotherapic beams

    NASA Astrophysics Data System (ADS)

    Berra, A.; Conti, V.; Lietti, D.; Milan, L.; Novati, C.; Ostinelli, A.; Prest, M.; Romanó, C.; Vallazza, E.

    2015-02-01

    This paper describes the development of a scintillator dosimeter prototype for radiotherapic applications based on plastic scintillating fibers readout by Silicon PhotoMultipliers. The dosimeter, whose probes are water equivalent, could be used for quality control measurements, beam characterization and in vivo dosimetry, allowing a real time measurement of the dose spatial distribution. This paper describes the preliminary percentual depth dose scan performed with clinical 6 and 18 MV photon beams, comparing the results with a reference curve. The measurements were performed using a Varian Clinac iX linear accelerator at the Radiotherapy Department of the St. Anna Hospital in Como (IT). The prototype has given promising results, allowing real time measurements of relative dose without applying any correction factors.

  20. Research on High-Bandgap Materials and Amorphous Silicon-Based Solar Cells, Final Technical Report, 15 May 1994-15 January 1998

    SciTech Connect

    Schiff, E. A.; Gu, Q.; Jiang, L.

    1998-12-28

    This report describes work performed by Syracuse University under this subcontract. Researchers developed a technique based on electroabsorption measurements for obtaining quantitative estimates of the built-in potential Vbi in a-Si:H-based heterostructure solar cells incorporating microcrystalline or a-SiC:H p layers. Using this new electroabsorption technique, researchers confirmed previous estimates of Vbi {yields} 1.0 V in a-Si:H solar cells with ''conventional'' intrinsic layers and either microcrystalline or a-SiC:H p layers. Researchers also explored the recent claim that light-soaking of a-Si:H substantially changes the polarized electroabsorption associated with interband optical transitions (and hence, not defect transitions). Researchers confirmed measurements of improved (5') holemore » drift mobilities in some specially prepared a-Si:H samples. Disturbingly, solar cells made with such materials did not show improved efficiencies. Researchers significantly clarified the relationship of ambipolar diffusion-length measurements to hole drift mobilities in a-Si:H, and have shown that the photocapacitance measurements can be interpreted in terms of hole drift mobilities in amorphous silicon. They also completed a survey of thin BP:H and BPC:H films prepared by plasma deposition using phosphine, diborane, trimethylboron, and hydrogen as precursor gases.« less

  1. Highly conducting and wide band gap phosphorous doped nc-Si–QD/a-SiC films as n-type window layers for solar cells

    SciTech Connect

    Kar, Debjit; Das, Debajyoti, E-mail: erdd@iacs.res.in

    2016-05-23

    Nano-crystalline silicon quantum dots (Si-QDs) embedded in the phosphorous doped amorphous silicon carbide (a-SiC) matrix has been successfully prepared at a low temperature (300 °C) by inductively coupled plasma assisted chemical vapor deposition (ICP-CVD) system from (SiH{sub 4} + CH{sub 4})-plasma with PH{sub 3} as the doping gas. The effect of PH{sub 3} flow rate on structural, optical and electrical properties of the films has been studied. Phosphorous doped nc-Si–QD/a-SiC films with high optical band gap (>1.9 eV) and superior conductivity (~10{sup −2} S cm{sup −1}) are obtained, which could be appropriately used as n-type window layers for nc-Si solarmore » cells in n-i-p configuration.« less

  2. Opto-electronic properties of P-doped nc-Si-QD/a-SiC:H thin films as foundation layer for all-Si solar cells in superstrate configuration

    NASA Astrophysics Data System (ADS)

    Kar, Debjit; Das, Debajyoti

    2016-07-01

    With the advent of nc-Si solar cells having improved stability, the efficient growth of nc-Si i-layer of the top cell of an efficient all-Si solar cell in the superstrate configuration prefers nc-Si n-layer as its substrate. Accordingly, a wide band gap and high conducting nc-Si alloy material is a basic requirement at the n-layer. Present investigation deals with the development of phosphorous doped n-type nanocrystalline silicon quantum dots embedded in hydrogenated amorphous silicon carbide (nc-Si-QD/a-SiC:H) hetero-structure films, wherein the optical band gap can be widened by the presence of Si-C bonds in the amorphous matrix and the embedded high density tiny nc-Si-QDs could provide high electrical conductivity, particularly in P-doped condition. The nc-Si-QDs simultaneously facilitate further widening of the optical band gap by virtue of the associated quantum confinement effect. A complete investigation has been made on the electrical transport phenomena involving charge transfer by tunneling and thermionic emission prevailing in n-type nc-Si-QD/a-SiC:H thin films. Their correlation with different phases of the specific heterostructure has been carried out for detailed understanding of the material, in order to improve its device applicability. The n-type nc-Si-QD/a-SiC:H films exhibit a thermally activated electrical transport above room temperature and multi-phonon hopping (MPH) below room temperature, involving defects in the amorphous phase and the grain-boundary region. The n-type nc-Si-QD/a-SiC:H films grown at ˜300 °C, demonstrating wide optical gap ˜1.86-1.96 eV and corresponding high electrical conductivity ˜4.5 × 10-1-1.4 × 10-2 S cm-1, deserve to be an effective foundation layer for the top nc-Si sub-cell of all-Si solar cells in n-i-p structure with superstrate configuration.

  3. Opto-electronic properties of P-doped nc-Si–QD/a-SiC:H thin films as foundation layer for all-Si solar cells in superstrate configuration

    SciTech Connect

    Kar, Debjit; Das, Debajyoti, E-mail: erdd@iacs.res.in

    2016-07-14

    With the advent of nc-Si solar cells having improved stability, the efficient growth of nc-Si i-layer of the top cell of an efficient all-Si solar cell in the superstrate configuration prefers nc-Si n-layer as its substrate. Accordingly, a wide band gap and high conducting nc-Si alloy material is a basic requirement at the n-layer. Present investigation deals with the development of phosphorous doped n-type nanocrystalline silicon quantum dots embedded in hydrogenated amorphous silicon carbide (nc-Si–QD/a-SiC:H) hetero-structure films, wherein the optical band gap can be widened by the presence of Si–C bonds in the amorphous matrix and the embedded high densitymore » tiny nc-Si–QDs could provide high electrical conductivity, particularly in P-doped condition. The nc-Si–QDs simultaneously facilitate further widening of the optical band gap by virtue of the associated quantum confinement effect. A complete investigation has been made on the electrical transport phenomena involving charge transfer by tunneling and thermionic emission prevailing in n-type nc-Si–QD/a-SiC:H thin films. Their correlation with different phases of the specific heterostructure has been carried out for detailed understanding of the material, in order to improve its device applicability. The n-type nc-Si–QD/a-SiC:H films exhibit a thermally activated electrical transport above room temperature and multi-phonon hopping (MPH) below room temperature, involving defects in the amorphous phase and the grain-boundary region. The n-type nc-Si–QD/a-SiC:H films grown at ∼300 °C, demonstrating wide optical gap ∼1.86–1.96 eV and corresponding high electrical conductivity ∼4.5 × 10{sup −1}–1.4 × 10{sup −2} S cm{sup −1}, deserve to be an effective foundation layer for the top nc-Si sub-cell of all-Si solar cells in n-i-p structure with superstrate configuration.« less

  4. Electrospinning Nanofiber Based Organic Solar Cell

    NASA Astrophysics Data System (ADS)

    Yang, Zhenhua; Liu, Ying; Moffa, Maria; Nam, Chang-Yong; Pisignano, Dario; Rafailovich, Miriam

    Bulk heterojunction (BHJ) polymer solar cells are an area of intense interest due to their potential to result in printable, inexpensive solar cells which can be processed onto flexible substrates. The active layer is typically spin coated from the solution of polythiophene derivatives (donor) and fullerenes (acceptor) and interconnected domains are formed because of phase separation. However, the power conversion efficiency (PCE) of BHJ solar cell is restricted by the presence of unfavorable morphological features, including dead ends or isolated domains. Here we MEH-PPV:PVP:PCBM electrospun nanofiber into BHJ solar cell for the active layer morphology optimization. Larger interfacial area between donor and acceptor is abtained with electrospinning method and the high aspect ratio of the MEH-PPV:PVP:PCBM nanofibers allow them to easily form a continuous pathway. The surface morphology is investigated with atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrospun nanofibers are discussed as a favorable structure for application in bulk-heterojunction organic solar cells. Electrospinning Nanofiber Based Bulk Heterojunction Organic Solar Cell.

  5. SOLAR-ISS: A new reference spectrum based on SOLAR/SOLSPEC observations

    NASA Astrophysics Data System (ADS)

    Meftah, M.; Damé, L.; Bolsée, D.; Hauchecorne, A.; Pereira, N.; Sluse, D.; Cessateur, G.; Irbah, A.; Bureau, J.; Weber, M.; Bramstedt, K.; Hilbig, T.; Thiéblemont, R.; Marchand, M.; Lefèvre, F.; Sarkissian, A.; Bekki, S.

    2018-03-01

    Context. Since April 5, 2008 and up to February 15, 2017, the SOLar SPECtrometer (SOLSPEC) instrument of the SOLAR payload on board the International Space Station (ISS) has performed accurate measurements of solar spectral irradiance (SSI) from the middle ultraviolet to the infrared (165 to 3088 nm). These measurements are of primary importance for a better understanding of solar physics and the impact of solar variability on climate. In particular, a new reference solar spectrum (SOLAR-ISS) is established in April 2008 during the solar minima of cycles 23-24 thanks to revised engineering corrections, improved calibrations, and advanced procedures to account for thermal and aging corrections of the SOLAR/SOLSPEC instrument. Aims: The main objective of this article is to present a new high-resolution solar spectrum with a mean absolute uncertainty of 1.26% at 1σ from 165 to 3000 nm. This solar spectrum is based on solar observations of the SOLAR/SOLSPEC space-based instrument. Methods: The SOLAR/SOLSPEC instrument consists of three separate double monochromators that use concave holographic gratings to cover the middle ultraviolet (UV), visible (VIS), and infrared (IR) domains. Our best ultraviolet, visible, and infrared spectra are merged into a single absolute solar spectrum covering the 165-3000 nm domain. The resulting solar spectrum has a spectral resolution varying between 0.6 and 9.5 nm in the 165-3000 nm wavelength range. We build a new solar reference spectrum (SOLAR-ISS) by constraining existing high-resolution spectra to SOLAR/SOLSPEC observed spectrum. For that purpose, we account for the difference of resolution between the two spectra using the SOLAR/SOLSPEC instrumental slit functions. Results: Using SOLAR/SOLSPEC data, a new solar spectrum covering the 165-3000 nm wavelength range is built and is representative of the 2008 solar minimum. It has a resolution better than 0.1 nm below 1000 nm and 1 nm in the 1000-3000 nm wavelength range. The new

  6. Spectroscopic Ellipsometry Studies of Thin Film a-Si:H Solar Cell Fabrication by Multichamber Deposition in the n-i-p Substrate Configuration

    NASA Astrophysics Data System (ADS)

    Dahal, Lila Raj

    Real time spectroscopic ellipsometry (RTSE), and ex-situ mapping spectroscopic ellipsometry (SE) are powerful characterization techniques capable of performance optimization and scale-up evaluation of thin film solar cells used in various photovoltaics technologies. These non-invasive optical probes employ multichannel spectral detection for high speed and provide high precision parameters that describe (i) thin film structure, such as layer thicknesses, and (ii) thin film optical properties, such as oscillator variables in analytical expressions for the complex dielectric function. These parameters are critical for evaluating the electronic performance of materials in thin film solar cells and also can be used as inputs for simulating their multilayer optical performance. In this Thesis, the component layers of thin film hydrogenated silicon (Si:H) solar cells in the n-i-p or substrate configuration on rigid and flexible substrate materials have been studied by RTSE and ex-situ mapping SE. Depositions were performed by magnetron sputtering for the metal and transparent conducting oxide contacts and by plasma enhanced chemical vapor deposition (PECVD) for the semiconductor doped contacts and intrinsic absorber layers. The motivations are first to optimize the thin film Si:H solar cell in n-i-p substrate configuration for single-junction small-area dot cells and ultimately to scale-up the optimized process to larger areas with minimum loss in device performance. Deposition phase diagrams for both i- and p -layers on 2" x 2" rigid borosilicate glass substrate were developed as functions of the hydrogen-to-silane flow ratio in PECVD. These phase diagrams were correlated with the performance parameters of the corresponding solar cells, fabricated in the Cr/Ag/ZnO/n/i/ p/ITO structure. In both cases, optimization was achieved when the layers were deposited in the protocrystalline phase. Identical solar cell structures were fabricated on 6" x 6" borosilicate glass with

  7. Detection of Hydrofluoric Acid by a SiO2 Sol-Gel Coating Fiber-Optic Probe Based on Reflection-Based Localized Surface Plasmon Resonance

    PubMed Central

    Chen, I-Cherng; Lin, Shiu-Shiung; Lin, Tsao-Jen; Du, Je-Kang

    2011-01-01

    A novel fiber-optic probe based on reflection-based localized surface plasmon resonance (LSPR) was developed to quantify the concentration of hydrofluoric acid (HF) in aqueous solutions. The LSPR sensor was constructed with a gold nanoparticle-modified PMMA fiber, integrated with a SiO2 sol-gel coating. This fiber-sensor was utilized to assess the relationship between HF concentration and SiO2 sol-gel layer etching reduction. The results demonstrated the LSPR sensor was capable of detecting HF-related erosion of hydrofluoric acid solutions of concentrations ranging from 1% to 5% using Relative RI Change Rates. The development of the LSPR sensor constitutes the basis of a detector with significant sensitivity for practical use in monitoring HF solution concentrations. PMID:22319388

  8. Biourbanism: Solar based urban and regional design

    SciTech Connect

    Williams, D.

    1999-07-01

    New neighborhoods for an additional one billion people will need to be constructed on the planet within the next 10 years. If the historic patterns of growth continue--the sprawl, the congestion, the draining of swamps, the loss of agricultural land--the requirement for all basic resources will outstrip the availability. While this is of great concern, it is the destruction of an acceptable quality of life--the sense of place--that will be the most difficult and expensive to change. An essential step to reverse the direction of this undesirable future is changing the design and planning of these communities to work withmore » resident solar energies, regional biology, local renewable resources, and sustainable urban planning and design principles. Design can make a difference. This paper develops the view that the solar approach must include urban and regional design and presents solar-based renewable resources example of the design of regions.« less

  9. Simulation of a high-efficiency silicon-based heterojunction solar cell

    NASA Astrophysics Data System (ADS)

    Jian, Liu; Shihua, Huang; Lü, He

    2015-04-01

    The basic parameters of a-Si:H/c-Si heterojunction solar cells, such as layer thickness, doping concentration, a-Si:H/c-Si interface defect density, and the work functions of the transparent conducting oxide (TCO) and back surface field (BSF) layer, are crucial factors that influence the carrier transport properties and the efficiency of the solar cells. The correlations between the carrier transport properties and these parameters and the performance of a-Si:H/c-Si heterojunction solar cells were investigated using the AFORS-HET program. Through the analysis and optimization of a TCO/n-a-Si:H/i-a-Si:H/p-c-Si/p+-a-Si:H/Ag solar cell, a photoelectric conversion efficiency of 27.07% (VOC) 749 mV, JSC: 42.86 mA/cm2, FF: 84.33%) was obtained through simulation. An in-depth understanding of the transport properties can help to improve the efficiency of a-Si:H/c-Si heterojunction solar cells, and provide useful guidance for actual heterojunction with intrinsic thin layer (HIT) solar cell manufacturing. Project supported by the National Natural Science Foundation of China (No. 61076055), the Open Project Program of Surface Physics Laboratory (National Key Laboratory) of Fudan University (No. FDS-KL2011-04), the Zhejiang Provincial Science and Technology Key Innovation Team (No. 2011R50012), and the Zhejiang Provincial Key Laboratory (No. 2013E10022).

  10. a-SiNx:H-based ultra-low power resistive random access memory with tunable Si dangling bond conduction paths

    PubMed Central

    Jiang, Xiaofan; Ma, Zhongyuan; Xu, Jun; Chen, Kunji; Xu, Ling; Li, Wei; Huang, Xinfan; Feng, Duan

    2015-01-01

    The realization of ultra-low power Si-based resistive switching memory technology will be a milestone in the development of next generation non-volatile memory. Here we show that a high performance and ultra-low power resistive random access memory (RRAM) based on an Al/a-SiNx:H/p+-Si structure can be achieved by tuning the Si dangling bond conduction paths. We reveal the intrinsic relationship between the Si dangling bonds and the N/Si ratio x for the a-SiNx:H films, which ensures that the programming current can be reduced to less than 1 μA by increasing the value of x. Theoretically calculated current-voltage (I–V ) curves combined with the temperature dependence of the I–V characteristics confirm that, for the low-resistance state (LRS), the Si dangling bond conduction paths obey the trap-assisted tunneling model. In the high-resistance state (HRS), conduction is dominated by either hopping or Poole–Frenkel (P–F) processes. Our introduction of hydrogen in the a-SiNx:H layer provides a new way to control the Si dangling bond conduction paths, and thus opens up a research field for ultra-low power Si-based RRAM. PMID:26508086

  11. a-SiNx:H-based ultra-low power resistive random access memory with tunable Si dangling bond conduction paths.

    PubMed

    Jiang, Xiaofan; Ma, Zhongyuan; Xu, Jun; Chen, Kunji; Xu, Ling; Li, Wei; Huang, Xinfan; Feng, Duan

    2015-10-28

    The realization of ultra-low power Si-based resistive switching memory technology will be a milestone in the development of next generation non-volatile memory. Here we show that a high performance and ultra-low power resistive random access memory (RRAM) based on an Al/a-SiNx:H/p(+)-Si structure can be achieved by tuning the Si dangling bond conduction paths. We reveal the intrinsic relationship between the Si dangling bonds and the N/Si ratio x for the a-SiNx:H films, which ensures that the programming current can be reduced to less than 1 μA by increasing the value of x. Theoretically calculated current-voltage (I-V) curves combined with the temperature dependence of the I-V characteristics confirm that, for the low-resistance state (LRS), the Si dangling bond conduction paths obey the trap-assisted tunneling model. In the high-resistance state (HRS), conduction is dominated by either hopping or Poole-Frenkel (P-F) processes. Our introduction of hydrogen in the a-SiNx:H layer provides a new way to control the Si dangling bond conduction paths, and thus opens up a research field for ultra-low power Si-based RRAM.

  12. Microcalcification detectability using a bench-top prototype photon-counting breast CT based on a Si strip detector.

    PubMed

    Cho, Hyo-Min; Ding, Huanjun; Barber, William C; Iwanczyk, Jan S; Molloi, Sabee

    2015-07-01

    than 0.89 ± 0.07 for μCas larger than 120 μm in diameter at a MGD of 3 mGy. The experimental results using a 1.6 cm diameter breast phantom showed that the prototype system can achieve an average AUC greater than 0.98 ± 0.01 for μCas larger than 140 μm in diameter using an entrance exposure of 1.2 mGy. The proposed photon-counting breast CT system based on a Si strip detector can potentially offer superior image quality to detect μCa with a lower dose level than a standard two-view mammography.

  13. Forming-free performance of a-SiN x :H-based resistive switching memory obtained by oxygen plasma treatment.

    PubMed

    Zhang, Xinxin; Ma, Zhongyuan; Zhang, Hui; Liu, Jian; Yang, Huafeng; Sun, Yang; Tan, Dinwen; Li, Wei; Xu, Ling; Chen, Kuiji; Feng, Duan

    2018-06-15

    An a-SiN x -based resistive random access memory (RRAM) device with a forming-free characteristic has significant potentials for the industrialization of the next-generation memories. We demonstrate that a forming-free a-SiN x O y RRAM device can be achieved by an oxygen plasma treatment of ultra-thin a-SiN x :H films. Electron spin resonance spectroscopy reveals that Si dangling bonds with a high density (10 19 cm -3 ) are distributed in the initial state, which exist in the forms of Si 2 N≡Si·, SiO 2 ≡Si·, O 3 ≡Si·, and N 3 ≡Si·. X-ray photoelectron spectroscopy and temperature-dependent current analyses reveal that the silicon dangling bonds induced by the oxygen plasma treatment and external electric field contribute to the low resistance state (LRS). For the high resistance state (HRS), the rupture of the silicon dangling bond pathway is attributed to the partial passivation of Si dangling bonds by H + and O 2- . Both LRS and HRS transmissions obey the hopping conduction model. The proposed oxygen plasma treatment, introduced to generate a high density of Si dangling bonds in the SiN x O y :H films, provides a new approach to forming-free RRAM devices.

  14. Forming-free performance of a-SiN x :H-based resistive switching memory obtained by oxygen plasma treatment

    NASA Astrophysics Data System (ADS)

    Zhang, Xinxin; Ma, Zhongyuan; Zhang, Hui; Liu, Jian; Yang, Huafeng; Sun, Yang; Tan, Dinwen; Li, Wei; Xu, Ling; Chen, Kuiji; Feng, Duan

    2018-06-01

    An a-SiN x -based resistive random access memory (RRAM) device with a forming-free characteristic has significant potentials for the industrialization of the next-generation memories. We demonstrate that a forming-free a-SiN x O y RRAM device can be achieved by an oxygen plasma treatment of ultra-thin a-SiN x :H films. Electron spin resonance spectroscopy reveals that Si dangling bonds with a high density (1019 cm‑3) are distributed in the initial state, which exist in the forms of Si2N≡Si·, SiO2≡Si·, O3≡Si·, and N3≡Si·. X-ray photoelectron spectroscopy and temperature-dependent current analyses reveal that the silicon dangling bonds induced by the oxygen plasma treatment and external electric field contribute to the low resistance state (LRS). For the high resistance state (HRS), the rupture of the silicon dangling bond pathway is attributed to the partial passivation of Si dangling bonds by H+ and O2‑. Both LRS and HRS transmissions obey the hopping conduction model. The proposed oxygen plasma treatment, introduced to generate a high density of Si dangling bonds in the SiN x O y :H films, provides a new approach to forming-free RRAM devices.

  15. 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

  16. Investigation of the radiation resistance of triple-junction a-Si:H alloy solar cells irradiated with 1.00 MeV protons

    NASA Technical Reports Server (NTRS)

    Lord, Kenneth R., II; Walters, Michael R.; Woodyard, James R.

    1993-01-01

    The effect of 1.00 MeV proton irradiation on hydrogenated amorphous silicon alloy triple-junction solar cells is reported for the first time. The cells were designed for radiation resistance studies and included 0.35 cm(sup 2) active areas on 1.0 by 2.0 cm(sup 2) glass superstrates. Three cells were irradiated through the bottom contact at each of six fluences between 5.10E12 and 1.46E15 cm(sup -2). The effect of the irradiations was determined with light current-voltage measurements. Proton irradiation degraded the cell power densities from 8.0 to 98 percent for the fluences investigated. Annealing irradiated cells at 200 C for two hours restored the power densities to better than 90 percent. The cells exhibited radiation resistances which are superior to cells reported in the literature for fluences less than 1E14 cm(sup -2).

  17. The National Solar Radiation Data Base (NSRDB)

    DOE PAGES

    Sengupta, Manajit; Xie, Yu; Lopez, Anthony; ...

    2018-03-19

    The National Solar Radiation Data Base (NSRDB), consisting of solar radiation and meteorological data over the United States and regions of the surrounding countries, is a publicly open dataset that has been created and disseminated during the last 23 years. This paper briefly reviews the complete package of surface observations, models, and satellite data used for the latest version of the NSRDB as well as improvements in the measurement and modeling technologies deployed in the NSRDB over the years. The current NSRDB provides solar irradiance at a 4-km horizontal resolution for each 30-min interval from 1998 to 2016 computed bymore » the National Renewable Energy Laboratory's (NREL's) Physical Solar Model (PSM) and products from the National Oceanic and Atmospheric Administration's (NOAA's) Geostationary Operational Environmental Satellite (GOES), the National Ice Center's (NIC's) Interactive Multisensor Snow and Ice Mapping System (IMS), and the National Aeronautics and Space Administration's (NASA's) Moderate Resolution Imaging Spectroradiometer (MODIS) and Modern Era Retrospective analysis for Research and Applications, version 2 (MERRA-2). The NSRDB irradiance data have been validated and shown to agree with surface observations with mean percentage biases within 5% and 10% for global horizontal irradiance (GHI) and direct normal irradiance (DNI), respectively. The data can be freely accessed via https://nsrdb.nrel.gov or through an application programming interface (API). During the last 23 years, the NSRDB has been widely used by an ever-growing group of researchers and industry both directly and through tools such as NREL's System Advisor Model.« less

  18. The National Solar Radiation Data Base (NSRDB)

    SciTech Connect

    Sengupta, Manajit; Xie, Yu; Lopez, Anthony

    The National Solar Radiation Data Base (NSRDB), consisting of solar radiation and meteorological data over the United States and regions of the surrounding countries, is a publicly open dataset that has been created and disseminated during the last 23 years. This paper briefly reviews the complete package of surface observations, models, and satellite data used for the latest version of the NSRDB as well as improvements in the measurement and modeling technologies deployed in the NSRDB over the years. The current NSRDB provides solar irradiance at a 4-km horizontal resolution for each 30-min interval from 1998 to 2016 computed bymore » the National Renewable Energy Laboratory's (NREL's) Physical Solar Model (PSM) and products from the National Oceanic and Atmospheric Administration's (NOAA's) Geostationary Operational Environmental Satellite (GOES), the National Ice Center's (NIC's) Interactive Multisensor Snow and Ice Mapping System (IMS), and the National Aeronautics and Space Administration's (NASA's) Moderate Resolution Imaging Spectroradiometer (MODIS) and Modern Era Retrospective analysis for Research and Applications, version 2 (MERRA-2). The NSRDB irradiance data have been validated and shown to agree with surface observations with mean percentage biases within 5% and 10% for global horizontal irradiance (GHI) and direct normal irradiance (DNI), respectively. The data can be freely accessed via https://nsrdb.nrel.gov or through an application programming interface (API). During the last 23 years, the NSRDB has been widely used by an ever-growing group of researchers and industry both directly and through tools such as NREL's System Advisor Model.« less

  19. A synthetic method of solar spectrum based on LED

    NASA Astrophysics Data System (ADS)

    Wang, Ji-qiang; Su, Shi; Zhang, Guo-yu; Zhang, Jian

    2017-10-01

    A synthetic method of solar spectrum which based on the spectral characteristics of the solar spectrum and LED, and the principle of arbitrary spectral synthesis was studied by using 14 kinds of LED with different central wavelengths.The LED and solar spectrum data were selected by Origin Software firstly, then calculated the total number of LED for each center band by the transformation relation between brightness and illumination and Least Squares Curve Fit in Matlab.Finally, the spectrum curve of AM1.5 standard solar spectrum was obtained. The results met the technical indexes of the solar spectrum matching with ±20% and the solar constant with >0.5.

  20. Development of a Si/ SiO 2-based double quantum dot charge qubit with dispersive microwave readout

    NASA Astrophysics Data System (ADS)

    House, M. G.; Henry, E.; Schmidt, A.; Naaman, O.; Siddiqi, I.; Pan, H.; Xiao, M.; Jiang, H. W.

    2011-03-01

    Coupling of a high-Q microwave resonator to superconducting qubits has been successfully used to prepare, manipulate, and read out the state of a single qubit, and to mediate interactions between qubits. Our work is geared toward implementing this architecture in a semiconductor qubit. We present the design and development of a lateral quantum dot in which a superconducting microwave resonator is capacitively coupled to a double dot charge qubit. The device is a silicon MOSFET structure with a global gate which is used to accumulate electrons at a Si/ Si O2 interface. A set of smaller gates are used to deplete these electrons to define a double quantum dot and adjacent conduction channels. Two of these depletion gates connect directly to the conductors of a 6 GHz co-planar stripline resonator. We present measurements of transport and conventional charge sensing used to characterize the double quantum dot, and demonstrate that it is possible to reach the few-electron regime in this system. This work is supported by the DARPA-QuEST program.

  1. Radial junction solar cells based on heterojunction with intrinsic thin layer (HIT) structure

    NASA Astrophysics Data System (ADS)

    Shen, Haoting

    conformality of a-Si:H deposited by PECVD using SiH4 and H 2 on high aspect ratio trench structures. Experimentally, it was found that the a-Si:H growth rate increased with increasing SiH4 flow rate up to a point after which it saturated at a maximum growth rate. In addition, it was found that higher SiH4 flow rates resulted in improved thickness uniformity along the trenches. A model based on gas transport and surface reaction of SiH3 in trenches was developed and was used to explain the experimental results and predict conditions that would yield improved thickness uniformity. The knowledge gained in the PECVD deposition studies was then used to prepare HIT radial junction Si pillar array solar cell devices. Deep reactive ion etching (DRIE) was used to prepare Si pillar arrays on p-type (111) c-Si wafers. A process was developed to prepare n-type a-Si:H films from SiH 4 and H2, with PH3 as doping gas. Indium tin oxide (ITO) deposited by sputter deposition and Al-doped ZnO deposited by atomic layer deposition (ALD) were evaluated as transparent conductive top contacts to the n-type a-Si:H layer. By adjusting the SiH4/H2 gas flow ratio, intrinsic a-Si:H was grown on the c-Si surface without epitaxial micro-crystalline growth. Continuous and pulsed deposition modes were investigated for deposition of the intrinsic and n-type a-Si:H layers on the c-Si pillars. The measurements of device light performance shown that slightly lower short circuit current density (Jsc, 32 mA/cm2 to 35 mA/cm 2) but higher open circuit voltage (Voc, 0.56 V to .47 V) were obtained on the pulsed devices. As the result, higher efficiency (11.6%) was achieved on the pulsed devices (10.6% on the continuous device). The improved performance of the pulsed deposition devices was explained as arising from a higher SiH3 concentration in the initial plasma which lead to a more uniform layer thickness. Planar and radial junction Si wire array HIT solar cell devices were then fabricated and the device performance

  2. The temperature dependence of the characteristics of crystalline-silicon-based heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Sachenko, A. V.; Kryuchenko, Yu. V.; Kostylyov, V. P.; Korkishko, R. M.; Sokolovskyi, I. O.; Abramov, A. S.; Abolmasov, S. N.; Andronikov, D. A.; Bobyl', A. V.; Panaiotti, I. E.; Terukov, E. I.; Titov, A. S.; Shvarts, M. Z.

    2016-03-01

    Temperature dependences of the photovoltaic characteristics of ( p)a-Si/( i)a-Si:H/( n)c-Si singlecrystalline- silicon based heterojunction-with-intrinsic-thin-layer (HIT) solar cells have been measured in a temperature range of 80-420 K. The open-circuit voltage ( V OC), fill factor ( FF) of the current-voltage ( I-U) characteristic, and maximum output power ( P max) reach limiting values in the interval of 200-250 K on the background of monotonic growth in the short-circuit current ( I SC) in a temperature range of 80-400 K. At temperatures below this interval, the V OC, FF, and P max values exhibit a decrease. It is theoretically justified that a decrease in the photovoltaic energy conversion characteristics of solar cells observed on heating from 250 to 400 K is related to exponential growth in the intrinsic conductivity. At temperatures below 200 K, the I-U curve shape exhibits a change that is accompanied by a drop in V OC. Possible factors that account for the decrease in V OC, FF, and P max are considered.

  3. 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.

  4. A Space Based Solar Power Satellite System

    NASA Astrophysics Data System (ADS)

    Engel, J. M.; Polling, D.; Ustamujic, F.; Yaldiz, R.; et al.

    2002-01-01

    (SPoTS) supplying other satellites with energy. SPoTS is due to be commercially viable and operative in 2020. of Technology designed the SPoTS during a full-time design period of six weeks as a third year final project. The team, organized according to the principles of systems engineering, first conducted a literature study on space wireless energy transfer to select the most suitable candidates for use on the SPoTS. After that, several different system concepts have been generated and evaluated, the most promising concept being worked out in greater detail. km altitude. Each SPoTS satellite has a 50m diameter inflatable solar collector that focuses all received sunlight. Then, the received sunlight is further redirected by means of four pointing mirrors toward four individual customer satellites. A market-analysis study showed, that providing power to geo-stationary communication satellites during their eclipse would be most beneficial. At arrival at geo-stationary orbit, the focused beam has expended to such an extent that its density equals one solar flux. This means that customer satellites can continue to use their regular solar arrays during their eclipse for power generation, resulting in a satellite battery mass reduction. the customer satellites in geo-stationary orbit, the transmitted energy beams needs to be pointed with very high accuracy. Computations showed that for this degree of accuracy, sensors are needed, which are not mainstream nowadays. Therefore further research must be conducted in this area in order to make these high-accuracy-pointing systems commercially attractive for use on the SPoTS satellites around 2020. Total 20-year system lifetime cost for 18 SPoT satellites are estimated at approximately USD 6 billion [FY2001]. In order to compete with traditional battery-based satellite power systems or possible ground based wireless power transfer systems the price per kWh for the customer must be significantly lower than the present one

  5. Optical Amplifier Based Space Solar Power

    NASA Technical Reports Server (NTRS)

    Fork, Richard L.

    2001-01-01

    The objective was to design a safe optical power beaming system for use in space. Research was focused on identification of strategies and structures that would enable achievement near diffraction limited optical beam quality, highly efficient electrical to optical conversion, and high average power in combination in a single system. Efforts centered on producing high efficiency, low mass of the overall system, low operating temperature, precision pointing and tracking capability, compatibility with useful satellite orbits, component and system reliability, and long component and system life in space. A system based on increasing the power handled by each individual module to an optimum and the number of modules in the complete structure was planned. We were concerned with identifying the most economical and rapid path to commercially viable safe space solar power.

  6. Novel Flexible Plastic-Based Solar Cells

    DTIC Science & Technology

    2012-10-19

    Fabrication of newly designed hybrid solar cells that are composed of a electron transport layer ( TiO2 ), a light sensitizing layer (NCs), and a hole...coating and spraying techniques, to produce broad-band light harvesting hybrid solar cells with bulk and layered heterojunction of inorganic...fabrication of hybrid bulk heterojunction photovoltaic cell using a blend film of polymer-inorganic NCs, 2) Fabrication of newly designed hybrid solar

  7. Deployed Base Solar Power (BRIEFING SLIDES)

    DTIC Science & Technology

    2009-09-01

    various time intervals. Data Acquisitions and Components:  FieldPoint  Current, Voltage, and Power Transducers  POA Pyranometers  Solar...Tracking Pyranometer  Weather Station  kWh Meter Parameters being monitored:  Solar Module Temperatures  Ambient Temperature  Wind Speed  Wind

  8. Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes/polymer composite thin film.

    PubMed

    Rajanna, Pramod Mulbagal; Gilshteyn, Evgenia; Yagafarov, Timur; Alekseeva, Alena; Anisimov, Anton; Sergeev, Oleg; Neumueller, Alex; Bereznev, Sergei; Maricheva, Jelena; Nasibulin, Albert

    2018-01-09

    We report a simple approach to fabricate hybrid solar cells (HSCs) based on a single-walled carbon nanotube (SWCNT) film and a thin film hydrogenated amorphous silicon (a-Si:H). Randomly oriented high quality SWCNTs with an enhanced conductivity by means of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are used as a window layer and a front electrode. A series of HSCs are fabricated in ambient conditions with different SWCNT film thicknesses. The polymethylmethacrylate layer drop-casted on fabricated HSCs reduces the reflection fourfold and enhances the short-circuit Jsc, open-circuit Voc, and efficiency by nearly 10%. A state-of-the-art J-V performance is shown for SWCNT/a-Si HSC with an open-circuit voltage of 900 mV and efficiency of 3.4% under simulated one-sun AM 1.5G direct illumination. © 2018 IOP Publishing Ltd.

  9. Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes and polymer composite thin film.

    PubMed

    Rajanna, Pramod M; Gilshteyn, Evgenia P; Yagafarov, Timur; Aleekseeva, Alena K; Anisimov, Anton S; Neumüller, Alex; Sergeev, Oleg; Bereznev, Sergei; Maricheva, Jelena; Nasibulin, Albert G

    2018-01-31

    We report a simple approach to fabricate hybrid solar cells (HSCs) based on a single-walled carbon nanotube (SWCNT) film and thin film hydrogenated amorphous silicon (a-Si:H). Randomly oriented high-quality SWCNTs with conductivity enhanced by means of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are used as a window layer and a front electrode. A series of HSCs are fabricated in ambient conditions with varying SWCNT film thicknesses. The polymethylmethacrylate layer drop-casted on fabricated HSCs reduces the reflection fourfold and enhances the short-circuit J sc , open-circuit V oc , and efficiency by nearly 10%. A state-of-the-art J-V performance is shown for SWCNT/a-Si HSC with an open-circuit voltage of 900 mV and an efficiency of 3.4% under simulated one-sun AM 1.5 G direct illumination.

  10. Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes and polymer composite thin film

    NASA Astrophysics Data System (ADS)

    Rajanna, Pramod M.; Gilshteyn, Evgenia P.; Yagafarov, Timur; Aleekseeva, Alena K.; Anisimov, Anton S.; Neumüller, Alex; Sergeev, Oleg; Bereznev, Sergei; Maricheva, Jelena; Nasibulin, Albert G.

    2018-03-01

    We report a simple approach to fabricate hybrid solar cells (HSCs) based on a single-walled carbon nanotube (SWCNT) film and thin film hydrogenated amorphous silicon (a-Si:H). Randomly oriented high-quality SWCNTs with conductivity enhanced by means of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are used as a window layer and a front electrode. A series of HSCs are fabricated in ambient conditions with varying SWCNT film thicknesses. The polymethylmethacrylate layer drop-casted on fabricated HSCs reduces the reflection fourfold and enhances the short-circuit J sc , open-circuit V oc , and efficiency by nearly 10%. A state-of-the-art J-V performance is shown for SWCNT/a-Si HSC with an open-circuit voltage of 900 mV and an efficiency of 3.4% under simulated one-sun AM 1.5 G direct illumination.

  11. PINPIN a-Si:H based structures for X-ray image detection using the laser scanning technique

    NASA Astrophysics Data System (ADS)

    Fernandes, M.; Vygranenko, Y.; Vieira, M.

    2015-05-01

    Conventional film based X-ray imaging systems are being replaced by their digital equivalents. Different approaches are being followed by considering direct or indirect conversion, with the later technique dominating. The typical, indirect conversion, X-ray panel detector uses a phosphor for X-ray conversion coupled to a large area array of amorphous silicon based optical sensors and a couple of switching thin film transistors (TFT). The pixel information can then be readout by switching the correspondent line and column transistors, routing the signal to an external amplifier. In this work we follow an alternative approach, where the electrical switching performed by the TFT is replaced by optical scanning using a low power laser beam and a sensing/switching PINPIN structure, thus resulting in a simpler device. The optically active device is a PINPIN array, sharing both front and back electrical contacts, deposited over a glass substrate. During X-ray exposure, each sensing side photodiode collects photons generated by the scintillator screen (560 nm), charging its internal capacitance. Subsequently a laser beam (445 nm) scans the switching diodes (back side) retrieving the stored charge in a sequential way, reconstructing the image. In this paper we present recent work on the optoelectronic characterization of the PINPIN structure to be incorporated in the X-ray image sensor. The results from the optoelectronic characterization of the device and the dependence on scanning beam parameters are presented and discussed. Preliminary results of line scans are also presented.

  12. The Application Design of Solar Radio Spectrometer Based on FPGA

    NASA Astrophysics Data System (ADS)

    Du, Q. F.; Chen, R. J.; Zhao, Y. C.; Feng, S. W.; Chen, Y.; Song, Y.

    2017-10-01

    The Solar radio spectrometer is the key instrument to observe solar radio. By programing the computer software, we control the AD signal acquisition card which is based on FPGA to get a mass of data. The data are transferred by using PCI-E port. This program has realized the function of timing data collection, finding data in specific time and controlling acquisition meter in real time. It can also map the solar radio power intensity graph. By doing the experiment, we verify the reliability of solar radio spectrum instrument, in the meanwhile, the instrument simplifies the operation in observing the sun.

  13. Design and evaluation of a SiPM-based large-area detector module for positron emission imaging

    NASA Astrophysics Data System (ADS)

    Alva-Sánchez, H.; Murrieta-Rodríguez, T.; Calva-Coraza, E.; Martínez-Dávalos, A.; Rodríguez-Villafuerte, M.

    2018-03-01

    The design and evaluation of a large-area detector module for positron emission imaging applications, is presented. The module features a SensL ArrayC-60035-64P-PCB solid state detector (8×8 array of tileable silicon photomultipliers by SensL, 7.2 mm pitch) covering a total area of 57.4×57.4 mm2. The detector module was formed using a pixelated array of 40×40 lutetium-yttrium oxyorthosilicate (LYSO) scintillator crystal elements with 1.43 mm pitch. A 7 mm thick coupling light guide was used to allow light sharing between adjacent SiPM. A 16-channel symmetric charge division (SCD) readout board was designed to multiplex the number of signals from 64 to 16 (8 columns and 8 rows) and a center-of-gravity algorithm to identify the position. Data acquisition and digitization was accomplished using a custom-made system based on FPGAs boards. Crystal maps were obtained using 18F-positron sources and Voronoi diagrams were used to correct for geometric distortions and to generate a non-uniformity correction matrix. All measurements were taken at a controlled room temperature of 22oC. The crystal maps showed minor distortion, 90% of the 1600 total crystal elements could be identified, a mean peak-to-valley ratio of 4.3 was obtained and a 10.8% mean energy resolution for 511 keV annihilation photons was determined. The performance of the detector using our own readout board was compared to that using two different commercially readout boards using the same detector module arrangement. We show that these large-area SiPM arrays, combined with a 16-channel SCD readout board, can offer high spatial resolution, excellent energy resolution and detector uniformity and thus, can be used for positron emission imaging applications.

  14. Predicting efficiency of solar cells based on transparent conducting electrodes

    NASA Astrophysics Data System (ADS)

    Kumar, Ankush

    2017-01-01

    Efficiency of a solar cell is directly correlated with the performance of its transparent conducting electrodes (TCEs) which dictates its two core processes, viz., absorption and collection efficiencies. Emerging designs of a TCE involve active networks of carbon nanotubes, silver nanowires and various template-based techniques providing diverse structures; here, voids are transparent for optical transmittance while the conducting network acts as a charge collector. However, it is still not well understood as to which kind of network structure leads to an optimum solar cell performance; therefore, mostly an arbitrary network is chosen as a solar cell electrode. Herein, we propose a new generic approach for understanding the role of TCEs in determining the solar cell efficiency based on analysis of shadowing and recombination losses. A random network of wires encloses void regions of different sizes and shapes which permit light transmission; two terms, void fraction and equivalent radius, are defined to represent the TCE transmittance and wire spacings, respectively. The approach has been applied to various literature examples and their solar cell performance has been compared. To obtain high-efficiency solar cells, optimum density of the wires and their aspect ratio as well as active layer thickness are calculated. Our findings show that a TCE well suitable for one solar cell may not be suitable for another. For high diffusion length based solar cells, the void fraction of the network should be low while for low diffusion length based solar cells, the equivalent radius should be lower. The network with less wire spacing compared to the diffusion length behaves similar to continuous film based TCEs (such as indium tin oxide). The present work will be useful for architectural as well as material engineering of transparent electrodes for improvisation of solar cell performance.

  15. MLP based LOGSIG transfer function for solar generation monitoring

    NASA Astrophysics Data System (ADS)

    Hashim, Fakroul Ridzuan; Din, Muhammad Faiz Md; Ahmad, Shahril; Arif, Farah Khairunnisa; Rizman, Zairi Ismael

    2018-02-01

    Solar panel is one of the renewable energy that can reduce the environmental pollution and have a wide potential of application. The exact solar prediction model will give a big impact on the management of solar power plants and the design of solar energy systems. This paper attempts to use Multilayer Perceptron (MLP) neural network based transfer function. The MLP network can be used to calculate the temperature module (TM) in Malaysia. This can be done by simulating the collected data of four weather variables which are the ambient temperature (TA), local wind speed (VW), solar radiation flux (GT) and the relative humidity (RH) as the input into the neural network. The transfer function will be applied to the 14 types of training. Finally, an equation from the best training algorithm will be deduced to calculate the temperature module based on the input of weather variables in Malaysia.

  16. Solids-based concentrated solar power receiver

    DOEpatents

    None

    2018-04-10

    A concentrated solar power (CSP) system includes channels arranged to convey a flowing solids medium descending under gravity. The channels form a light-absorbing surface configured to absorb solar flux from a heliostat field. The channels may be independently supported, for example by suspension, and gaps between the channels are sized to accommodate thermal expansion. The light absorbing surface may be sloped so that the inside surfaces of the channels proximate to the light absorbing surface define downward-slanting channel floors, and the flowing solids medium flows along these floors. Baffles may be disposed inside the channels and oriented across the direction of descent of the flowing solids medium. The channels may include wedge-shaped walls forming the light-absorbing surface and defining multiple-reflection light paths for solar flux from the heliostat field incident on the light-absorbing surface.

  17. Solar-based navigation for robotic explorers

    NASA Astrophysics Data System (ADS)

    Shillcutt, Kimberly Jo

    2000-12-01

    This thesis introduces the application of solar position and shadowing information to robotic exploration. Power is a critical resource for robots with remote, long-term missions, so this research focuses on the power generation capabilities of robotic explorers during navigational tasks, in addition to power consumption. Solar power is primarily considered, with the possibility of wind power also contemplated. Information about the environment, including the solar ephemeris, terrain features, time of day, and surface location, is incorporated into a planning structure, allowing robots to accurately predict shadowing and thus potential costs and gains during navigational tasks. By evaluating its potential to generate and expend power, a robot can extend its lifetime and accomplishments. The primary tasks studied are coverage patterns, with a variety of plans developed for this research. The use of sun, terrain and temporal information also enables new capabilities of identifying and following sun-synchronous and sun-seeking paths. Digital elevation maps are combined with an ephemeris algorithm to calculate the altitude and azimuth of the sun from surface locations, and to identify and map shadows. Solar navigation path simulators use this information to perform searches through two-dimensional space, while considering temporal changes. Step by step simulations of coverage patterns also incorporate time in addition to location. Evaluations of solar and wind power generation, power consumption, area coverage, area overlap, and time are generated for sets of coverage patterns, with on-board environmental information linked to the simulations. This research is implemented on the Nomad robot for the Robotic Antarctic Meteorite Search. Simulators have been developed for coverage pattern tests, as well as for sun-synchronous and sun-seeking path searches. Results of field work and simulations are reported and analyzed, with demonstrated improvements in efficiency

  18. Semiconductor-based Multilayer Selective Solar Absorber for Unconcentrated Solar Thermal Energy Conversion

    SciTech Connect

    Thomas, Nathan H.; Chen, Zhen; Fan, Shanhui

    Solar thermal energy conversion has attracted substantial renewed interest due to its applications in industrial heating, air conditioning, and electricity generation. Achieving stagnation temperatures exceeding 200 °C, pertinent to these technologies, with unconcentrated sunlight requires spectrally selective absorbers with exceptionally low emissivity in the thermal wavelength range and high visible absorptivity for the solar spectrum. In this Communication, we then report a semiconductor-based multilayer selective absorber that exploits the sharp drop in optical absorption at the bandgap energy to achieve a measured absorptance of 76% at solar wavelengths and a low emittance of approximately 5% at thermal wavelengths. In fieldmore » tests, we obtain a peak temperature of 225 °C, comparable to that achieved with state-of-the-art selective surfaces. Furthemore, with straightforward optimization to improve solar absorption, our work shows the potential for unconcentrated solar thermal systems to reach stagnation temperatures exceeding 300 °C, thereby eliminating the need for solar concentrators for mid-temperature solar applications such as supplying process heat« less

  19. Semiconductor-based Multilayer Selective Solar Absorber for Unconcentrated Solar Thermal Energy Conversion.

    PubMed

    Thomas, Nathan H; Chen, Zhen; Fan, Shanhui; Minnich, Austin J

    2017-07-13

    Solar thermal energy conversion has attracted substantial renewed interest due to its applications in industrial heating, air conditioning, and electricity generation. Achieving stagnation temperatures exceeding 200 °C, pertinent to these technologies, with unconcentrated sunlight requires spectrally selective absorbers with exceptionally low emissivity in the thermal wavelength range and high visible absorptivity for the solar spectrum. In this Communication, we report a semiconductor-based multilayer selective absorber that exploits the sharp drop in optical absorption at the bandgap energy to achieve a measured absorptance of 76% at solar wavelengths and a low emittance of approximately 5% at thermal wavelengths. In field tests, we obtain a peak temperature of 225 °C, comparable to that achieved with state-of-the-art selective surfaces. With straightforward optimization to improve solar absorption, our work shows the potential for unconcentrated solar thermal systems to reach stagnation temperatures exceeding 300 °C, thereby eliminating the need for solar concentrators for mid-temperature solar applications such as supplying process heat.

  20. Solar-rechargeable battery based on photoelectrochemical water oxidation: Solar water battery

    PubMed Central

    Kim, Gonu; Oh, Misol; Park, Yiseul

    2016-01-01

    As an alternative to the photoelectrochemical water splitting for use in the fuel cells used to generate electrical power, this study set out to develop a solar energy rechargeable battery system based on photoelectrochemical water oxidation. We refer to this design as a “solar water battery”. The solar water battery integrates a photoelectrochemical cell and battery into a single device. It uses a water oxidation reaction to simultaneously convert and store solar energy. With the solar water battery, light striking the photoelectrode causes the water to be photo-oxidized, thus charging the battery. During the discharge process, the solar water battery reduces oxygen to water with a high coulombic efficiency (>90%) and a high average output voltage (0.6 V). Because the reduction potential of oxygen is more positive [E0 (O2/H2O) = 1.23 V vs. NHE] than common catholytes (e.g., iodide, sulfur), a high discharge voltage is produced. The solar water battery also exhibits a superior storage ability, maintaining 99% of its specific discharge capacitance after 10 h of storage, without any evidence of self-discharge. The optimization of the cell design and configuration, taking the presence of oxygen in the cell into account, was critical to achieving an efficient photocharge/discharge. PMID:27629362

  1. Solar-rechargeable battery based on photoelectrochemical water oxidation: Solar water battery.

    PubMed

    Kim, Gonu; Oh, Misol; Park, Yiseul

    2016-09-15

    As an alternative to the photoelectrochemical water splitting for use in the fuel cells used to generate electrical power, this study set out to develop a solar energy rechargeable battery system based on photoelectrochemical water oxidation. We refer to this design as a "solar water battery". The solar water battery integrates a photoelectrochemical cell and battery into a single device. It uses a water oxidation reaction to simultaneously convert and store solar energy. With the solar water battery, light striking the photoelectrode causes the water to be photo-oxidized, thus charging the battery. During the discharge process, the solar water battery reduces oxygen to water with a high coulombic efficiency (>90%) and a high average output voltage (0.6 V). Because the reduction potential of oxygen is more positive [E(0) (O2/H2O) = 1.23 V vs. NHE] than common catholytes (e.g., iodide, sulfur), a high discharge voltage is produced. The solar water battery also exhibits a superior storage ability, maintaining 99% of its specific discharge capacitance after 10 h of storage, without any evidence of self-discharge. The optimization of the cell design and configuration, taking the presence of oxygen in the cell into account, was critical to achieving an efficient photocharge/discharge.

  2. Semiconductor-based Multilayer Selective Solar Absorber for Unconcentrated Solar Thermal Energy Conversion

    DOE PAGES

    Thomas, Nathan H.; Chen, Zhen; Fan, Shanhui; ...

    2017-07-13

    Solar thermal energy conversion has attracted substantial renewed interest due to its applications in industrial heating, air conditioning, and electricity generation. Achieving stagnation temperatures exceeding 200 °C, pertinent to these technologies, with unconcentrated sunlight requires spectrally selective absorbers with exceptionally low emissivity in the thermal wavelength range and high visible absorptivity for the solar spectrum. In this Communication, we then report a semiconductor-based multilayer selective absorber that exploits the sharp drop in optical absorption at the bandgap energy to achieve a measured absorptance of 76% at solar wavelengths and a low emittance of approximately 5% at thermal wavelengths. In fieldmore » tests, we obtain a peak temperature of 225 °C, comparable to that achieved with state-of-the-art selective surfaces. Furthemore, with straightforward optimization to improve solar absorption, our work shows the potential for unconcentrated solar thermal systems to reach stagnation temperatures exceeding 300 °C, thereby eliminating the need for solar concentrators for mid-temperature solar applications such as supplying process heat« less

  3. Tantalum-based semiconductors for solar water splitting.

    PubMed

    Zhang, Peng; Zhang, Jijie; Gong, Jinlong

    2014-07-07

    Solar energy utilization is one of the most promising solutions for the energy crises. Among all the possible means to make use of solar energy, solar water splitting is remarkable since it can accomplish the conversion of solar energy into chemical energy. The produced hydrogen is clean and sustainable which could be used in various areas. For the past decades, numerous efforts have been put into this research area with many important achievements. Improving the overall efficiency and stability of semiconductor photocatalysts are the research focuses for the solar water splitting. Tantalum-based semiconductors, including tantalum oxide, tantalate and tantalum (oxy)nitride, are among the most important photocatalysts. Tantalum oxide has the band gap energy that is suitable for the overall solar water splitting. The more negative conduction band minimum of tantalum oxide provides photogenerated electrons with higher potential for the hydrogen generation reaction. Tantalates, with tunable compositions, show high activities owning to their layered perovskite structure. (Oxy)nitrides, especially TaON and Ta3N5, have small band gaps to respond to visible-light, whereas they can still realize overall solar water splitting with the proper positions of conduction band minimum and valence band maximum. This review describes recent progress regarding the improvement of photocatalytic activities of tantalum-based semiconductors. Basic concepts and principles of solar water splitting will be discussed in the introduction section, followed by the three main categories regarding to the different types of tantalum-based semiconductors. In each category, synthetic methodologies, influencing factors on the photocatalytic activities, strategies to enhance the efficiencies of photocatalysts and morphology control of tantalum-based materials will be discussed in detail. Future directions to further explore the research area of tantalum-based semiconductors for solar water splitting

  4. Ground-based measurements of the solar diameter during the rising phase of solar cycle 24

    NASA Astrophysics Data System (ADS)

    Meftah, M.; Corbard, T.; Irbah, A.; Ikhlef, R.; Morand, F.; Renaud, C.; Hauchecorne, A.; Assus, P.; Borgnino, J.; Chauvineau, B.; Crepel, M.; Dalaudier, F.; Damé, L.; Djafer, D.; Fodil, M.; Lesueur, P.; Poiet, G.; Rouzé, M.; Sarkissian, A.; Ziad, A.; Laclare, F.

    2014-09-01

    Context. For the past thirty years, modern ground-based time-series of the solar radius have shown different apparent variations according to different instruments. The origins of these variations may result from the observer, the instrument, the atmosphere, or the Sun. Solar radius measurements have been made for a very long time and in different ways. Yet we see inconsistencies in the measurements. Numerous studies of solar radius variation appear in the literature, but with conflicting results. These measurement differences are certainly related to instrumental effects or atmospheric effects. Use of different methods (determination of the solar radius), instruments, and effects of Earth's atmosphere could explain the lack of consistency on the past measurements. A survey of the solar radius has been initiated in 1975 by Francis Laclare, at the Calern site of the Observatoire de la Côte d'Azur (OCA). Several efforts are currently made from space missions to obtain accurate solar astrometric measurements, for example, to probe the long-term variations of solar radius, their link with solar irradiance variations, and their influence on the Earth climate. Aims: The Picard program includes a ground-based observatory consisting of different instruments based at the Calern site (OCA, France). This set of instruments has been named "Picard Sol" and consists of a Ritchey-Chrétien telescope providing full-disk images of the Sun in five narrow-wavelength bandpasses (centered on 393.37, 535.7, 607.1, 782.2, and 1025.0 nm), a Sun-photometer that measures the properties of atmospheric aerosol, a pyranometer for estimating a global sky-quality index, a wide-field camera that detects the location of clouds, and a generalized daytime seeing monitor allowing us to measure the spatio-temporal parameters of the local turbulence. Picard Sol is meant to perpetuate valuable historical series of the solar radius and to initiate new time-series, in particular during solar cycle 24

  5. Space-Based Solar Power System Architecture

    DTIC Science & Technology

    2012-12-01

    alternatives to fossil fuels: nuclear fission reactors, hydroelectric power, wind turbines and solar power to name just a few. Each has advantages...powered laser could give people or wildlife serious burns or cause blindness and possibly even death depending on exposure proximity and time. 11

  6. Basic performance evaluation of a Si-PM array-based LGSO phoswich DOI block detector for a high-resolution small animal PET system.

    PubMed

    Yamamoto, Seiichi

    2013-07-01

    The silicon photomultiplier (Si-PM) is a promising photodetector for PET. However, it remains unclear whether Si-PM can be used for a depth-of-interaction (DOI) detector based on the decay time differences of the scintillator where pulse shape analysis is used. For clarification, we tested the Hamamatsu 4 × 4 Si-PM array (S11065-025P) combined with scintillators that used different decay times to develop DOI block detectors using the pulse shape analysis. First, Ce-doped Gd(2)SiO(5) (GSO) scintillators of 0.5 mol% Ce were arranged in a 4 × 4 matrix and were optically coupled to the center of each pixel of the Si-PM array for measurement of the energy resolution as well as its gain variations according to the temperature. Then two types of Ce-doped Lu(1.9)Gd(0.1)Si0(5) (LGSO) scintillators, 0.025 mol% Ce (decay time: ~31 ns) and 0.75 mol% Ce (decay time: ~46 ns), were optically coupled in the DOI direction, arranged in a 11 × 7 matrix, and optically coupled to a Si-PM array for testing of the possibility of a high-resolution DOI detector. The energy resolution of the Si-PM array-based GSO block detector was 18 ± 4.4 % FWHM for a Cs-137 gamma source (662 keV). Less than 1 mm crystals were clearly resolved in the position map of the LGSO DOI block detector. The peak-to-valley ratio (P/V) derived from the pulse shape spectra of the LGSO DOI block detector was 2.2. These results confirmed that Si-PM array-based DOI block detectors are promising for high-resolution small animal PET systems.

  7. Experimental characterization of a solar cooker with thermal energy storage based on solar salt

    NASA Astrophysics Data System (ADS)

    Coccia, G.; Di Nicola, G.; Tomassetti, S.; Gabrielli, G.; Chieruzzi, M.; Pierantozzi, M.

    2017-11-01

    High temperature solar cooking allows to cook food fast and with good efficiency. An unavoidable drawback of this technology is that it requires nearly clear-sky conditions. In addition, evening cooking is difficult to be accomplished, particularly on the winter season during which solar radiation availability is limited to a few hours in the afternoon in most of countries. These restrictions could be overcome using a cooker thermal storage unit (TSU). In this work, a TSU based on solar salt was studied. The unit consists of two metal concentric cylindrical vessels, connected together to form a double-walled vessel. The volume between walls was filled with a certain amount of nitrate based phase change material (solar salt). In order to characterize the TSU, a test bench used to assess solar cooker performance was adopted. Experimental load tests with the TSU were carried out to evaluate the cooker performance. The obtained preliminary results show that the adoption of the solar salt TSU seems to allow both the opportunity of evening cooking and the possibility to better stabilize the cooker temperature when sky conditions are variable.

  8. New solar selective coating based on carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Abendroth, Thomas; Leupolt, Beate; Mäder, Gerrit; Härtel, Paul; Grählert, Wulf; Althues, Holger; Kaskel, Stefan; Beyer, Eckhard

    2016-05-01

    Carbon nanotubes (CNTs) can be applied to assemble a new type of solar selective coating system for solar thermal applications. In this work the predominant absorption processes occurring by interaction with π-plasmon and Van Hove singularities (VHS) were investigated by UV-VIS-NIR spectroscopy and ellipsometry. Not only optical properties for as deposited SWCNT thin films itself, but also the potential for systematic tailoring will be presented. Besides low cost technologies required, the adjustability of optical properties, as well as their thermal stability render CNT based solar selective coatings as promising alternative to commercially available coating systems.

  9. Imaging lysosomal highly reactive oxygen species and lighting up cancer cells and tumors enabled by a Si-rhodamine-based near-infrared fluorescent probe.

    PubMed

    Zhang, Hongxing; Liu, Jing; Liu, Chenlu; Yu, Pengcheng; Sun, Minjia; Yan, Xiaohan; Guo, Jian-Ping; Guo, Wei

    2017-07-01

    Lysosomes have recently been regarded as the attractive pharmacological targets for selectively killing of cancer cells via lysosomal cell death (LCD) pathway that is closely associated with reactive oxygen species (ROS). However, the details on the ROS-induced LCD of cancer cells are still poorly understood, partially due to the absence of a lysosome-targetable, robust, and biocompatible imaging tool for ROS. In this work, we brought forward a Si-rhodamine-based fluorescent probe, named PSiR, which could selectively and sensitively image the pathologically more relavent highly reactive oxygen species (hROS: HClO, HO, and ONOO - ) in lysosomes of cancer cells. Compared with many of the existing hROS fluorescent probes, its superiorities are mainly embodied in the high stability against autoxidation and photoxidation, near-infrared exitation and emission, fast fluorescence off-on response, and specific lysosomal localization. Its practicality has been demonstrated by the real-time imaging of hROS generation in lysosomes of human non-small-cell lung cancer cells stimulated by anticancer drug β-lapachone. Moreover, the probe was sensitive enough for basal hROS in cancer cells, allowing its further imaging applications to discriminate not only cancer cells from normal cells, but also tumors from healthy tissues. Overall, our results strongly indicated that PSiR is a very promising imaging tool for the studies of ROS-related LCD of cancer cells, screening of new anticancer drugs, and early diagnosis of cancers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. A Solar Position Sensor Based on Image Vision.

    PubMed

    Ruelas, Adolfo; Velázquez, Nicolás; Villa-Angulo, Carlos; Acuña, Alexis; Rosales, Pedro; Suastegui, José

    2017-07-29

    Solar collector technologies operate with better performance when the Sun beam direction is normal to the capturing surface, and for that to happen despite the relative movement of the Sun, solar tracking systems are used, therefore, there are rules and standards that need minimum accuracy for these tracking systems to be used in solar collectors' evaluation. Obtaining accuracy is not an easy job, hence in this document the design, construction and characterization of a sensor based on a visual system that finds the relative azimuth error and height of the solar surface of interest, is presented. With these characteristics, the sensor can be used as a reference in control systems and their evaluation. The proposed sensor is based on a microcontroller with a real-time clock, inertial measurement sensors, geolocation and a vision sensor, that obtains the angle of incidence from the sunrays' direction as well as the tilt and sensor position. The sensor's characterization proved how a measurement of a focus error or a Sun position can be made, with an accuracy of 0.0426° and an uncertainty of 0.986%, which can be modified to reach an accuracy under 0.01°. The validation of this sensor was determined showing the focus error on one of the best commercial solar tracking systems, a Kipp & Zonen SOLYS 2. To conclude, the solar tracking sensor based on a vision system meets the Sun detection requirements and components that meet the accuracy conditions to be used in solar tracking systems and their evaluation or, as a tracking and orientation tool, on photovoltaic installations and solar collectors.

  11. A Solar Position Sensor Based on Image Vision

    PubMed Central

    Ruelas, Adolfo; Velázquez, Nicolás; Villa-Angulo, Carlos; Rosales, Pedro; Suastegui, José

    2017-01-01

    Solar collector technologies operate with better performance when the Sun beam direction is normal to the capturing surface, and for that to happen despite the relative movement of the Sun, solar tracking systems are used, therefore, there are rules and standards that need minimum accuracy for these tracking systems to be used in solar collectors’ evaluation. Obtaining accuracy is not an easy job, hence in this document the design, construction and characterization of a sensor based on a visual system that finds the relative azimuth error and height of the solar surface of interest, is presented. With these characteristics, the sensor can be used as a reference in control systems and their evaluation. The proposed sensor is based on a microcontroller with a real-time clock, inertial measurement sensors, geolocation and a vision sensor, that obtains the angle of incidence from the sunrays’ direction as well as the tilt and sensor position. The sensor’s characterization proved how a measurement of a focus error or a Sun position can be made, with an accuracy of 0.0426° and an uncertainty of 0.986%, which can be modified to reach an accuracy under 0.01°. The validation of this sensor was determined showing the focus error on one of the best commercial solar tracking systems, a Kipp & Zonen SOLYS 2. To conclude, the solar tracking sensor based on a vision system meets the Sun detection requirements and components that meet the accuracy conditions to be used in solar tracking systems and their evaluation or, as a tracking and orientation tool, on photovoltaic installations and solar collectors. PMID:28758935

  12. Innovative laser based solar cell scribing

    NASA Astrophysics Data System (ADS)

    Frei, Bruno; Schneeberger, Stefan; Witte, Reiner

    2011-03-01

    The solar photovoltaic market is continuously growing utilizing boths crystalline silicon (c-Si) as well as thin film technologies. This growth is directly dependant on the manufacturing costs for solar cells. Factors for cost reduction are innovative ideas for an optimization of precision and throughput. Lasers are excellent tools to provide highly efficient processes with impressive accuracy. They need to be used in combination with fast and precise motion systems for a maximum gain in the manufacturing process, yielding best cost of ownership. In this article such an innovative solution is presented for laser scribing in thin film Si modules. A combination of a new glass substrate holding system combined with a fast and precise motion system is the foundation for a cost effective scribing machine. In addition, the advantages of fiber lasers in beam delivery and beam quality guarantee not only shorter setup and down times but also high resolution and reproducibility for the scribing processes P1, P2 and P3. The precision of the whole system allows to reduce the dead zone to a minimum and therefore to improve the efficiency of the modules.

  13. Graphene-Based Photocatalysts for Solar-Fuel Generation.

    PubMed

    Xiang, Quanjun; Cheng, Bei; Yu, Jiaguo

    2015-09-21

    The production of solar fuel through photocatalytic water splitting and CO2 reduction using photocatalysts has attracted considerable attention owing to the global energy shortage and growing environmental problems. During the past few years, many studies have demonstrated that graphene can markedly enhance the efficiency of photocatalysts for solar-fuel generation because of its unique 2D conjugated structure and electronic properties. Herein we summarize the recent advances in the application of graphene-based photocatalysts for solar-fuel production, including CO2 reduction to hydrocarbon fuel and water splitting to H2. A brief overview of the fundamental principles for splitting of water and reduction of CO2 is given. The different roles of graphene in these graphene-based photocatalysts for improving photocatalytic performance are discussed. Finally, the perspectives on the challenges and opportunities for future research in this promising area are also presented. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Forbush Decrease Prediction Based on Remote Solar Observations

    NASA Astrophysics Data System (ADS)

    Dumbovic, Mateja; Vrsnak, Bojan; Calogovic, Jasa

    2016-04-01

    We study the relation between remote observations of coronal mass ejections (CMEs), their associated solar flares and short-term depressions in the galactic cosmic-ray flux (so called Forbush decreases). Statistical relations between Forbush decrease magnitude and several CME/flare parameters are examined. In general we find that Forbush decrease magnitude is larger for faster CMEs with larger apparent width, which is associated with stronger flares that originate close to the center of the solar disk and are (possibly) involved in a CME-CME interaction. The statistical relations are quantified and employed to forecast expected Forbush decrease magnitude range based on the selected remote solar observations of the CME and associated solar flare. Several verification measures are used to evaluate the forecast method. We find that the forecast is most reliable in predicting whether or not a CME will produce a Forbush decrease with a magnitude >3 %. The main advantage of the method is that it provides an early prediction, 1-4 days in advance. Based on the presented research, an online forecast tool was developed (Forbush Decrease Forecast Tool, FDFT) available at Hvar Observatory web page: http://oh.geof.unizg.hr/FDFT/fdft.php. We acknowledge the support of Croatian Science Foundation under the project 6212 "Solar and Stellar Variability" and of European social fond under the project "PoKRet".

  15. Solar astronomy

    NASA Technical Reports Server (NTRS)

    Rosner, Robert; Noyes, Robert; Antiochos, Spiro K.; Canfield, Richard C.; Chupp, Edward L.; Deming, Drake; Doschek, George A.; Dulk, George A.; Foukal, Peter V.; Gilliland, Ronald L.

    1991-01-01

    An overview is given of modern solar physics. Topics covered include the solar interior, the solar surface, the solar atmosphere, the Large Earth-based Solar Telescope (LEST), the Orbiting Solar Laboratory, the High Energy Solar Physics mission, the Space Exploration Initiative, solar-terrestrial physics, and adaptive optics. Policy and related programmatic recommendations are given for university research and education, facilitating solar research, and integrated support for solar research.

  16. New shortwave solar radiometer with information-based sparse sampling

    SciTech Connect

    Simpson, M.L.; Carnal, C.L.; Ericson, M.N.

    1991-01-01

    A new concept for a real-time shortwave solar radiometer is presented, based on the premise that high resolution measurements of the shortwave solar spectrum are needed only in wavelength regions where the atmospheric physics are changing rapidly with respect to {Lambda}. The design features holographic optical elements (HOEs) for nonuniform sampling of the spectrum, customized photocells, and temperature-compensated monolithic wide dynamic range amplifiers. Preliminary results show full spectrum reconstruction accuracies to < 3% with a 10:1 reduction in the number of photocells required. 9 refs.

  17. New shortwave solar radiometer with information-based sparse sampling

    SciTech Connect

    Simpson, M.L.; Carnal, C.L.; Ericson, M.N.

    1991-12-31

    A new concept for a real-time shortwave solar radiometer is presented, based on the premise that high resolution measurements of the shortwave solar spectrum are needed only in wavelength regions where the atmospheric physics are changing rapidly with respect to {Lambda}. The design features holographic optical elements (HOEs) for nonuniform sampling of the spectrum, customized photocells, and temperature-compensated monolithic wide dynamic range amplifiers. Preliminary results show full spectrum reconstruction accuracies to < 3% with a 10:1 reduction in the number of photocells required. 9 refs.

  18. Artificial Leaf Based on Artificial Photosynthesis for Solar Fuel Production

    DTIC Science & Technology

    2017-06-30

    AFRL-AFOSR-JP-TR-2017-0054 Artificial Leaf Based on Artificial Photosynthesis for Solar Fuel Production Mamoru Nango NAGOYA INSTITUTE OF TECHNOLOGY...for Solar Fuel Production 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386-14-1-4015 5c.  PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Mamoru Nango 5d...density immobilization of the photoreactants in the nanocavity inside PGP. The maximum production efficiency of formic acid inside the nanocavity was

  19. Solar optics-based active panel for solar energy storage and disinfection of greywater.

    PubMed

    Lee, W; Song, J; Son, J H; Gutierrez, M P; Kang, T; Kim, D; Lee, L P

    2016-09-01

    Smart city and innovative building strategies are becoming increasingly more necessary because advancing a sustainable building system is regarded as a promising solution to overcome the depleting water and energy. However, current sustainable building systems mainly focus on energy saving and miss a holistic integration of water regeneration and energy generation. Here, we present a theoretical study of a solar optics-based active panel (SOAP) that enables both solar energy storage and photothermal disinfection of greywater simultaneously. Solar collector efficiency of energy storage and disinfection rate of greywater have been investigated. Due to the light focusing by microlens, the solar collector efficiency is enhanced from 25% to 65%, compared to that without the microlens. The simulation of greywater sterilization shows that 100% disinfection can be accomplished by our SOAP for different types of bacteria including Escherichia coli . Numerical simulation reveals that our SOAP as a lab-on-a-wall system can resolve the water and energy problem in future sustainable building systems.

  20. Solar optics-based active panel for solar energy storage and disinfection of greywater

    PubMed Central

    Lee, W.; Song, J.; Son, J. H.; Gutierrez, M. P.; Kang, T.; Kim, D.; Lee, L. P.

    2016-01-01

    Smart city and innovative building strategies are becoming increasingly more necessary because advancing a sustainable building system is regarded as a promising solution to overcome the depleting water and energy. However, current sustainable building systems mainly focus on energy saving and miss a holistic integration of water regeneration and energy generation. Here, we present a theoretical study of a solar optics-based active panel (SOAP) that enables both solar energy storage and photothermal disinfection of greywater simultaneously. Solar collector efficiency of energy storage and disinfection rate of greywater have been investigated. Due to the light focusing by microlens, the solar collector efficiency is enhanced from 25% to 65%, compared to that without the microlens. The simulation of greywater sterilization shows that 100% disinfection can be accomplished by our SOAP for different types of bacteria including Escherichia coli. Numerical simulation reveals that our SOAP as a lab-on-a-wall system can resolve the water and energy problem in future sustainable building systems. PMID:27822328

  1. Ground-based Observations of Large Solar Flares Precursors

    NASA Astrophysics Data System (ADS)

    Sheyner, Olga; Smirnova, Anna; Snegirev, Sergey

    2010-05-01

    The importance problem of Solar-terrestrial physics is regular forecasting of solar activity phenomena, which negatively influence the human's health, operating safety, communication, radar sets and others. The opportunity of development of short-term forecasting technique of geoeffective solar flares is presented in this study. This technique is based on the effect of growth of pulsations of horizontal component of geomagnetic field before the solar proton flares. The long-period (30-60 minutes) pulsations of H-component of geomagnetic field are detected for the events of different intensity on March 22, 1991, November 4, 2001, and November 17, 2001 using the method of wavelet-analysis. Amplitudes of fluctuations of horizontal component of geomagnetic field with the 30-60 minute's periods grow at the most of tested stations during 0.5-3.5 days before the solar flares. The particularities of spectral component are studied for the stations situated on different latitudes. The assumptions about the reason of such precursors-fluctuations appearance are made.

  2. Solar Cell Polymer Based Active Ingredients PPV and PCBM

    NASA Astrophysics Data System (ADS)

    Hardeli, H.; Sanjaya, H.; Resikarnila, R.; Nitami H, R.

    2018-04-01

    A polymer solar cell is a solar cell based on a polymer bulk heterojunction structure using the method of thin film, which can convert solar energy into electrical energy. Absorption of light is carried by active material layer PPV: PCBM. This study aims to make solar cells tandem and know the value of converting solar energy into electrical energy and increase the value of efficiency generated through morphological control, ie annealing temperature and the ratio of active layer mixture. The active layer is positioned above the PEDOT:PSS layer on ITO glass substrate. The characterization results show the surface morphology of the PPV:PCBM active layer is quite evenly at annealing temperature of 165 ° C. The result of conversion of electrical energy with a UV light source in annealing samples with temperature 165 ° C is 0.03 mA and voltage of 4.085 V with an efficiency of 2.61% and mixed ratio variation was obtained in comparison of P3HT: PCBM is 1: 3

  3. Superthin Solar Cells Based on AIIIBV/Ge Heterostructures

    NASA Astrophysics Data System (ADS)

    Pakhanov, N. A.; Pchelyakov, O. P.; Vladimirov, V. M.

    2017-11-01

    A comparative analysis of the prospects of creating superthin, light-weight, and highly efficient solar cells based on AIIIBV/InGaAs and AIIIBV/Ge heterostructures is performed. Technological problems and prospects of each variant are discussed. A method of thinning of AIIIBV/Ge heterostructures with the use of an effective temporary carrier is proposed. The method allows the process to be performed almost with no risk of heterostructure fracture, thinning of the Ge junction down to several tens of micrometers (or even several micrometers), significant enhancement of the yield of good structures, and also convenient and reliable transfer of thinned solar cells to an arbitrary light and flexible substrate. Such a technology offers a possibility of creating high-efficiency thin and light solar cells for space vehicles on the basis of mass-produced AIIIBV/Ge heterostructures.

  4. Prediction of global solar irradiance based on time series analysis: Application to solar thermal power plants energy production planning

    SciTech Connect

    Martin, Luis; Marchante, Ruth; Cony, Marco

    2010-10-15

    Due to strong increase of solar power generation, the predictions of incoming solar energy are acquiring more importance. Photovoltaic and solar thermal are the main sources of electricity generation from solar energy. In the case of solar thermal energy plants with storage energy system, its management and operation need reliable predictions of solar irradiance with the same temporal resolution as the temporal capacity of the back-up system. These plants can work like a conventional power plant and compete in the energy stock market avoiding intermittence in electricity production. This work presents a comparisons of statistical models based on time seriesmore » applied to predict half daily values of global solar irradiance with a temporal horizon of 3 days. Half daily values consist of accumulated hourly global solar irradiance from solar raise to solar noon and from noon until dawn for each day. The dataset of ground solar radiation used belongs to stations of Spanish National Weather Service (AEMet). The models tested are autoregressive, neural networks and fuzzy logic models. Due to the fact that half daily solar irradiance time series is non-stationary, it has been necessary to transform it to two new stationary variables (clearness index and lost component) which are used as input of the predictive models. Improvement in terms of RMSD of the models essayed is compared against the model based on persistence. The validation process shows that all models essayed improve persistence. The best approach to forecast half daily values of solar irradiance is neural network models with lost component as input, except Lerida station where models based on clearness index have less uncertainty because this magnitude has a linear behaviour and it is easier to simulate by models. (author)« less

  5. Solar-wind predictions for the Parker Solar Probe orbit. Near-Sun extrapolations derived from an empirical solar-wind model based on Helios and OMNI observations

    NASA Astrophysics Data System (ADS)

    Venzmer, M. S.; Bothmer, V.

    2018-03-01

    Context. The Parker Solar Probe (PSP; formerly Solar Probe Plus) mission will be humanitys first in situ exploration of the solar corona with closest perihelia at 9.86 solar radii (R⊙) distance to the Sun. It will help answer hitherto unresolved questions on the heating of the solar corona and the source and acceleration of the solar wind and solar energetic particles. The scope of this study is to model the solar-wind environment for PSPs unprecedented distances in its prime mission phase during the years 2018 to 2025. The study is performed within the Coronagraphic German And US SolarProbePlus Survey (CGAUSS) which is the German contribution to the PSP mission as part of the Wide-field Imager for Solar PRobe. Aim. We present an empirical solar-wind model for the inner heliosphere which is derived from OMNI and Helios data. The German-US space probes Helios 1 and Helios 2 flew in the 1970s and observed solar wind in the ecliptic within heliocentric distances of 0.29 au to 0.98 au. The OMNI database consists of multi-spacecraft intercalibrated in situ data obtained near 1 au over more than five solar cycles. The international sunspot number (SSN) and its predictions are used to derive dependencies of the major solar-wind parameters on solar activity and to forecast their properties for the PSP mission. Methods: The frequency distributions for the solar-wind key parameters, magnetic field strength, proton velocity, density, and temperature, are represented by lognormal functions. In addition, we consider the velocity distributions bi-componental shape, consisting of a slower and a faster part. Functional relations to solar activity are compiled with use of the OMNI data by correlating and fitting the frequency distributions with the SSN. Further, based on the combined data set from both Helios probes, the parameters frequency distributions are fitted with respect to solar distance to obtain power law dependencies. Thus an empirical solar-wind model for the inner

  6. The Base Engine for Solar Stirling Power

    NASA Technical Reports Server (NTRS)

    Meijer, R. J.; Godett, T. M.

    1984-01-01

    A new concept in Stirling engine technology is embodied in the base engine now being developed at Stirling Thermal Motors, Inc. This is a versatile energy conversion unit suitable for many different applications and heat sources. The base engine, rated 40 kW at 2800 RPM, is a four-cylinder, double-acting variable displacement Stirling engine with pressurized crankcase and rotating shaft seal. Remote-heating technology is incorporated with a stacked-heat-exchanger configuration and a liquid metal heat pipe connected to a distinctly separate combustor or other heat source. High efficiency over a wide range of operating conditions, long life, low manufacturing cost and low material cost are specifically emphasized. The base engine, its design philosophy and approach, its projected performance, and some of its more attractive applications are described.

  7. The Solar Umbrella: A Low-cost Demonstration of Scalable Space Based Solar Power

    NASA Technical Reports Server (NTRS)

    Contreras, Michael T.; Trease, Brian P.; Sherwood, Brent

    2013-01-01

    Within the past decade, the Space Solar Power (SSP) community has seen an influx of stakeholders willing to entertain the SSP prospect of potentially boundless, base-load solar energy. Interested parties affiliated with the Department of Defense (DoD), the private sector, and various international entities have all agreed that while the benefits of SSP are tremendous and potentially profitable, the risk associated with developing an efficient end to end SSP harvesting system is still very high. In an effort to reduce the implementation risk for future SSP architectures, this study proposes a system level design that is both low-cost and seeks to demonstrate the furthest transmission of wireless power to date. The overall concept is presented and each subsystem is explained in detail with best estimates of current implementable technologies. Basic cost models were constructed based on input from JPL subject matter experts and assume that the technology demonstration would be carried out by a federally funded entity. The main thrust of the architecture is to demonstrate that a usable amount of solar power can be safely and reliably transmitted from space to the Earth's surface; however, maximum power scalability limits and their cost implications are discussed.

  8. Solar water heating system for a lunar base

    NASA Technical Reports Server (NTRS)

    Somers, Richard E.; Haynes, R. Daniel

    1992-01-01

    An investigation of the feasibility of using a solar water heater for a lunar base is described. During the investigation, computer codes were developed to model the lunar base configuration, lunar orbit, and heating systems. Numerous collector geometries, orientation variations, and system options were identified and analyzed. The results indicate that the recommended solar water heater could provide 88 percent of the design load and would not require changes in the overall lunar base design. The system would give a 'safe-haven' water heating capability and use only 7 percent to 10 percent as much electricity as an electric heating system. As a result, a fixed position photovoltaic array can be reduced by 21 sq m.

  9. Online educative activities for solar ultraviolet radiation based on measurements of cloud amount and solar exposures.

    PubMed

    Parisi, A V; Downs, N; Turner, J; Amar, A

    2016-09-01

    A set of online activities for children and the community that are based on an integrated real-time solar UV and cloud measurement system are described. These activities use the functionality of the internet to provide an educative tool for school children and the public on the influence of cloud and the angle of the sun above the horizon on the global erythemal UV or sunburning UV, the diffuse erythemal UV, the global UVA (320-400nm) and the vitamin D effective UV. Additionally, the units of UV exposure and UV irradiance are investigated, along with the meaning and calculation of the UV index (UVI). This research will help ensure that children and the general public are better informed about sun safety by improving their personal understanding of the daily and the atmospheric factors that influence solar UV radiation and the solar UV exposures of the various wavebands in the natural environment. The activities may correct common misconceptions of children and the public about UV irradiances and exposure, utilising the widespread reach of the internet to increase the public's awareness of the factors influencing UV irradiances and exposures in order to provide clear information for minimizing UV exposure, while maintaining healthy, outdoor lifestyles. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. A three solar cell system based on a self-supporting, transparent AlGaAs top solar cell

    NASA Technical Reports Server (NTRS)

    Negley, Gerald H.; Rhoads, Sandra L.; Terranova, Nancy E.; Mcneely, James B.; Barnett, Allen M.

    1989-01-01

    Development of a three solar cell stack can lead to practical efficiencies greater than 30 percent (1x,AM0). A theoretical efficiency limitation of 43.7 percent at AM0 and one sun is predicted by this model. Including expected losses, a practical system efficiency of 36.8 percent is anticipated. These calculations are based on a 1.93eV/1.43eV/0.89eV energy band gap combination. AlGaAs/GaAs/GaInAsP materials can be used with a six-terminal wiring configuration. The key issues for multijunction solar cells are the top and middle solar cell performance and the sub-bandgap transparency. AstroPower has developed a technique to fabricate AlGaAs solar cells on rugged, self-supporting, transparent AlGaAs substrates. Top solar cell efficiencies greater than 11 percent AM0 have been achieved. State-of-the-art GaAs or InP devices will be used for the middle solar cell. GaInAsP will be used to fabricate the bottom solar cell. This material is lattice-matched to InP and offers a wide range of bandgaps for optimization of the three solar cell stack. Liquid phase epitaxy is being used to grow the quaternary material. Initial solar cells have shown open-circuit voltages of 462 mV for a bandgap of 0.92eV. Design rules for the multijunction three solar cell stack are discussed. The progress in the development of the self-supporting AlGaAs top solar cell and the GaInAsP bottom solar cell is presented.

  11. 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.

  12. Tandem luminescent solar concentrators based on engineered quantum dots

    NASA Astrophysics Data System (ADS)

    Wu, Kaifeng; Li, Hongbo; Klimov, Victor I.

    2018-02-01

    Luminescent solar concentrators (LSCs) can serve as large-area sunlight collectors for terrestrial and space-based photovoltaics. Due to their high emission efficiencies and readily tunable emission and absorption spectra, colloidal quantum dots have emerged as a new and promising type of LSC fluorophore. Spectral tunability of the quantum dots also facilitates the realization of stacked multilayered LSCs, where enhanced performance is obtained through spectral splitting of incident sunlight, as in multijunction photovoltaics. Here, we demonstrate a large-area (>230 cm2) tandem LSC based on two types of nearly reabsorption-free quantum dots spectrally tuned for optimal solar-spectrum splitting. This prototype device exhibits a high optical quantum efficiency of 6.4% for sunlight illumination and solar-to-electrical power conversion efficiency of 3.1%. The efficiency gains due to the tandem architecture over single-layer devices quickly increase with increasing LSC size and can reach more than 100% in structures with window sizes of more than 2,500 cm2.

  13. Engineering solar cells based on correlative X-ray microscopy

    DOE PAGES

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

    2017-05-01

    In situ and operando measurement techniques combined with nanoscale resolution have proven invaluable in multiple fields of study. We argue that evaluating device performance as well as material behavior by correlative X-ray microscopy with <100 nm resolution can radically change the approach for optimizing absorbers, interfaces and full devices in solar cell research. Here, we thoroughly discuss the measurement technique of X-ray beam induced current and point out fundamental differences between measurements of wafer-based silicon and thin-film solar cells. Based on reports of the last years, we showcase the potential that X-ray microscopy measurements have in combination with in situmore » and operando approaches throughout the solar cell lifecycle: from the growth of individual layers to the performance under operating conditions and degradation mechanisms. Enabled by new developments in synchrotron beamlines, the combination of high spatial resolution with high brilliance and a safe working distance allows for the insertion of measurement equipment that can pave the way for a new class of experiments. When applied to photovoltaics research, we highlight today’s opportunities and challenges in the field of nanoscale X-ray microscopy, and give an outlook on future developments.« less

  14. Thermotropic and Thermochromic Polymer Based Materials for Adaptive Solar Control

    PubMed Central

    Seeboth, Arno; Ruhmann, Ralf; Mühling, Olaf

    2010-01-01

    The aim of this review is to present the actual status of development in adaptive solar control by use of thermotropic and organic thermochromic materials. Such materials are suitable for application in smart windows. In detail polymer blends, hydrogels, resins, and thermoplastic films with a reversible temperature-dependent switching behavior are described. A comparative evaluation of the concepts for these energy efficient materials is given as well. Furthermore, the change of strategy from ordinary shadow systems to intrinsic solar energy reflection materials based on phase transition components and a first remark about their realization is reported. Own current results concerning extruded films and high thermally stable casting resins with thermotropic properties make a significant contribution to this field. PMID:28883374

  15. Solar cells with perovskite-based light sensitization layers

    DOEpatents

    Kanatzidis, Mercouri G.; Chang, Robert P.H.; Stoumpos, Konstantinos; Lee, Byunghong

    2018-05-08

    Solar cells are provided which comprise an electron transporting layer and a light sensitizing layer of perovskite disposed over the surface of the electron transporting layer. The perovskite may have a formula selected from the group consisting of A2MX6, Z2MX6 or YMX6, wherein A is an alkali metal, M is a metal or a metalloid, X is a halide, Z is selected from the group consisting of a primary ammonium, an iminium, a secondary ammonium, a tertiary ammonium, and a quaternary ammonium, and Y has formula Mb(L)3, wherein Mb is a transition metal in the 2+ oxidation state L is an N--N neutral chelating ligand. Methods of making the solar cells are also provided, including methods based on electrospray deposition.

  16. Annealing characteristics of irradiated hydrogenated amorphous silicon solar cells

    NASA Technical Reports Server (NTRS)

    Payson, J. S.; Abdulaziz, S.; Li, Y.; Woodyard, J. R.

    1991-01-01

    It was shown that 1 MeV proton irradiation with fluences of 1.25E14 and 1.25E15/sq cm reduces the normalized I(sub SC) of a-Si:H solar cell. Solar cells recently fabricated showed superior radiation tolerance compared with cells fabricated four years ago; the improvement is probably due to the fact that the new cells are thinner and fabricated from improved materials. Room temperature annealing was observed for the first time in both new and old cells. New cells anneal at a faster rate than old cells for the same fluence. From the annealing work it is apparent that there are at least two types of defects and/or annealing mechanisms. One cell had improved I-V characteristics following irradiation as compared to the virgin cell. The work shows that the photothermal deflection spectroscopy (PDS) and annealing measurements may be used to predict the qualitative behavior of a-Si:H solar cells. It was anticipated that the modeling work will quantitatively link thin film measurements with solar cell properties. Quantitative predictions of the operation of a-Si:H solar cells in a space environment will require a knowledge of the defect creation mechanisms, defect structures, role of defects on degradation, and defect passivation and annealing mechanisms. The engineering data and knowledge base for justifying space flight testing of a-Si:H alloy based solar cells is being developed.

  17. Raster-Based Approach to Solar Pressure Modeling

    NASA Technical Reports Server (NTRS)

    Wright, Theodore W. II

    2013-01-01

    shown on the computer screen is composed of up to millions of pixels. Each of those pixels is associated with a small illuminated area of the spacecraft. For each pixel, it is possible to compute its position, angle (surface normal) from the view direction, and the spacecraft material (and therefore, optical coefficients) associated with that area. With this information, the area associated with each pixel can be modeled as a simple flat plate for calculating solar pressure. The vector sum of these individual flat plate models is a high-fidelity approximation of the solar pressure forces and torques on the whole vehicle. In addition to using optical coefficients associated with each spacecraft material to calculate solar pressure, a power generation coefficient is added for computing solar array power generation from the sum of the illuminated areas. Similarly, other area-based calculations, such as free molecular flow drag, are also enabled. Because the model rendering is separated from other calculations, it is relatively easy to add a new model to explore a new vehicle or mission configuration. Adding a new model is performed by adding OpenGL code, but a future version might read a mesh file exported from a computer-aided design (CAD) system to enable very rapid turnaround for new designs

  18. EFRC: Polymer-Based Materials for Harvesting Solar Energy (stimulus)"

    SciTech Connect

    Russell, Thomas P.

    The University of Massachusetts Amherst is proposing an Energy Frontier Research Center (EFRC) on Polymer-Based Materials for Harvesting Solar Energy that will integrate the widely complementary experimental and theoretical expertise of 23 faculty at UMass-Amherst Departments with researchers from the University of Massachusetts Lowell, University of Pittsburgh, the Pennsylvania State University and Konarka Technologies, Inc. Collaborative efforts with researchers at the Oak Ridge National Laboratory, the University of Bayreuth, Seoul National University and Tohoku University will complement and expand the experimental efforts in the EFRC. Our primary research aim of this EFRC is the development of hybrid polymer-based devices withmore » efficiencies more than twice the current organic-based devices, by combining expertise in the design and synthesis of photoactive polymers, the control and guidance of polymer-based assemblies, leadership in nanostructured polymeric materials, and the theory and modeling of non-equilibrium structures. A primary goal of this EFRC is to improve the collection and conversion efficiency of a broader spectral range of solar energy using the directed self-assembly of polymer-based materials so as to optimize the design and fabrication of inexpensive devices.« less

  19. Wet-chemistry based selective coatings for concentrating solar power

    NASA Astrophysics Data System (ADS)

    Maimon, Eran; Kribus, Abraham; Flitsanov, Yuri; Shkolnik, Oleg; Feuermann, Daniel; Zwicker, Camille; Larush, Liraz; Mandler, Daniel; Magdassi, Shlomo

    2013-09-01

    Spectrally selective coatings are common in low and medium temperature solar applications from solar water heating collectors to parabolic trough absorber tubes. They are also an essential element for high efficiency in higher temperature Concentrating Solar Power (CSP) systems. Selective coatings for CSP are usually prepared using advanced expensive methods such as sputtering and vapor deposition. In this work, coatings were prepared using low-cost wet-chemistry methods. Solutions based on Alumina and Silica sol gel were prepared and then dispersed with black spinel pigments. The black dispersions were applied by spray/roll coating methods on stainless steel plates. The spectral emissivity of sample coatings was measured in the temperature range between 200 and 500°C, while the spectral absorptivity was measured at room temperature and 500°C. Emissivity at wavelengths of 0.4-1.7 μm was evaluated indirectly using multiple measurements of directional reflectivity. Emissivity at wavelengths 2-14 μm was measured directly using a broadband IR camera that acquires the radiation emitted from the sample, and a range of spectral filters. Emissivity measurement results for a range of coated samples will be presented, and the impact of coating thickness, pigment loading, and surface preparation will be discussed.

  20. Space-based solar power conversion and delivery systems study

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Even at reduced rates of growth, the demand for electric power is expected to more than triple between now and 1995, and to triple again over the period 1995-2020. Without the development of new power sources and advanced transmission technologies, it may not be possible to supply electric energy at prices that are conductive to generalized economic welfare. Solar power is renewable and its conversion and transmission from space may be advantageous. The goal of this study is to assess the economic merit of space-based photovoltaic systems for power generation and a power relay satellite for power transmission. In this study, satellite solar power generation and transmission systems, as represented by current configurations of the Satellite Solar Station (SSPS) and the Power Relay Satellite (PRS), are compared with current and future terrestrial power generation and transmission systems to determine their technical and economic suitability for meeting power demands in the period of 1990 and beyond while meeting ever-increasing environmental and social constraints.

  1. Development of a Greek solar map based on solar model estimations

    NASA Astrophysics Data System (ADS)

    Kambezidis, H. D.; Psiloglou, B. E.; Kavadias, K. A.; Paliatsos, A. G.; Bartzokas, A.

    2016-05-01

    The realization of Renewable Energy Sources (RES) for power generation as the only environmentally friendly solution, moved solar systems to the forefront of the energy market in the last decade. The capacity of the solar power doubles almost every two years in many European countries, including Greece. This rise has brought the need for reliable predictions of meteorological data that can easily be utilized for proper RES-site allocation. The absence of solar measurements has, therefore, raised the demand for deploying a suitable model in order to create a solar map. The generation of a solar map for Greece, could provide solid foundations on the prediction of the energy production of a solar power plant that is installed in the area, by providing an estimation of the solar energy acquired at each longitude and latitude of the map. In the present work, the well-known Meteorological Radiation Model (MRM), a broadband solar radiation model, is engaged. This model utilizes common meteorological data, such as air temperature, relative humidity, barometric pressure and sunshine duration, in order to calculate solar radiation through MRM for areas where such data are not available. Hourly values of the above meteorological parameters are acquired from 39 meteorological stations, evenly dispersed around Greece; hourly values of solar radiation are calculated from MRM. Then, by using an integrated spatial interpolation method, a Greek solar energy map is generated, providing annual solar energy values all over Greece.

  2. Project SunSHINE: A Student Based Solar Research Program

    NASA Astrophysics Data System (ADS)

    Donahue, R.

    2000-12-01

    Eastchester Middle School (NY) is currently conducting an ongoing, interdisciplinary solar research program entitled Project SunSHINE, for Students Help Investigate Nature in Eastchester. Students are to determine how ultraviolet and visible light levels vary throughout the year at the school's geographic location, and to ascertain if any measured variations correlate to daily weather conditions or sunspot activity. The educational goal is to provide students the opportunity to conduct original and meaningful scientific research, while learning to work collaboratively with peers and teachers in accordance with national mathematics, science and technology standards. Project SunSHINE requires the student researchers to employ a number of technologies to collect and analyze data, including light sensors, astronomical imaging software, an onsite AirWatch Weather Station, Internet access to retrieve daily solar images from the National Solar Observatory's Kitt Peak Vacuum Telescope, and two wide field telescopes for live sunspot observations. The program has been integrated into the science, mathematics, health and computer technology classes. Solar and weather datasets are emailed weekly to physicist Dr. Gil Yanow of the Jet Propulsion Laboratory for inclusion in his global study of light levels. Dr. Yanow credited the Project SunSHINE student researchers last year for the discovery of an inverse relationship between relative humidity and ultraviolet light levels. The Journal News Golden Apple Awards named Project SunSHINE the 1999 New York Wired Applied Technology Award winner. This honor recognizes the year's outstanding educational technology program at both the elementary and secondary level, and included a grant of \\$20,000 to the research program. Teacher training and image processing software for Project SunSHINE has been supplied by The Use of Astronomy in Research Based Science Education (RBSE), a Teacher Enhancement Program funded by the National Science

  3. Cu2O-based solar cells using oxide semiconductors

    NASA Astrophysics Data System (ADS)

    Minami, Tadatsugu; Nishi, Yuki; Miyata, Toshihiro

    2016-01-01

    We describe significant improvements of the photovoltaic properties that were achieved in Al-doped ZnO (AZO)/n-type oxide semiconductor/p-type Cu2O heterojunction solar cells fabricated using p-type Cu2O sheets prepared by thermally oxidizing Cu sheets. The multicomponent oxide thin film used as the n-type semiconductor layer was prepared with various chemical compositions on non-intentionally heated Cu2O sheets under various deposition conditions using a pulsed laser deposition method. In Cu2O-based heterojunction solar cells fabricated using various ternary compounds as the n-type oxide thin-film layer, the best photovoltaic performance was obtained with an n-ZnGa2O4 thin-film layer. In most of the Cu2O-based heterojunction solar cells using multicomponent oxides composed of combinations of various binary compounds, the obtained photovoltaic properties changed gradually as the chemical composition was varied. However, with the ZnO-MgO and Ga2O3-Al2O3 systems, higher conversion efficiencies (η) as well as a high open circuit voltage (Voc) were obtained by using a relatively small amount of MgO or Al2O3, e.g., (ZnO)0.91-(MgO)0.09 and (Ga2O3)0.975-(Al2O3)0.025, respectively. When Cu2O-based heterojunction solar cells were fabricated using Al2O3-Ga2O3-MgO-ZnO (AGMZO) multicomponent oxide thin films deposited with metal atomic ratios of 10, 60, 10 and 20 at.% for the Al, Ga, Mg and Zn, respectively, a high Voc of 0.98 V and an η of 4.82% were obtained. In addition, an enhanced η and an improved fill factor could be achieved in AZO/n-type multicomponent oxide/p-type Cu2O heterojunction solar cells fabricated using Na-doped Cu2O (Cu2O:Na) sheets that featured a resistivity controlled by optimizing the post-annealing temperature and duration. Consequently, an η of 6.25% and a Voc of 0.84 V were obtained in a MgF2/AZO/n-(Ga2O3-Al2O3)/p-Cu2O:Na heterojunction solar cell fabricated using a Cu2O:Na sheet with a resistivity of approximately 10 Ω·cm and a (Ga0.975Al0

  4. Ferritin-based nanocrystals for solar energy harvesting

    NASA Astrophysics Data System (ADS)

    Colton, John; Erickson, Stephen; Olsen, Cameron; Embley, Jacob; Smith, Trevor; Watt, Richard

    2015-03-01

    Ferritin is a 12 nm diameter hollow protein with an 8 nm cavity that can be filled with a variety of nanocrystals (ferrihydrite being native). We report on several experiments with ferritin-based nanocrystals designed to utilize ferritin for solar energy harvesting. First, we have shown that the native band gap can be altered by controlling nanocrystal size, by replacing the native iron oxide core with other metal oxides, and by depositing halides and oxo-anions with the iron oxide core. This gives available band gaps of 1.6 to 2.3 eV. Theoretical efficiency calculations based on these band gaps show that the efficiency of a multi-junction solar cell based on layered structures of ferritin can be as high as 44.9 %, and up to 63.1 % if a ferritin-based material with band gap of 1.1 eV can be developed. For the latter case, the efficiencies remain quite high even in a current-matched configuration, namely 50.0 %. We have also demonstrated that photo-excitation of these materials can produce charge separation and give rise to usable electrons; we have used photo-excited electrons to reduce gold in solution and thereby produce gold nanoparticles on the surface of the ferritin. This technique can potentially be extended to platinum, whose nanoparticles catalyze water splitting. This research was partially supported by the Utah Office of Energy Development, Governor's Energy Leadership Scholars Program.

  5. Cobalt and Yttrium Modified TiO2 Nanotubes Based Dye-Sensitized Solar Cells for Solar-Energy Conversion

    NASA Astrophysics Data System (ADS)

    Shabanov, N. S.; Isaev, A. B.; Orudzhev, F. F.; Murliev, E. K.

    2018-01-01

    The solar-energy conversion in eosin-sensitized solar cells based on cobalt and yttrium modified TiO2 nanotubes has been studied.It is established that the doping with metal ions shifts the absorption edge for Co and Y doped titanium dioxide samples to longer and shorter wavelengths, respectively. The efficiency of solar energy conversion depends on the wide bandgap of the semiconductor anode and reaches a maximum (4.4%) for yttrium-doped TiO2 in comparison to that (4.1%) for pure titanium dioxide.

  6. Zinc-oxide-based nanostructured materials for heterostructure solar cells

    SciTech Connect

    Bobkov, A. A.; Maximov, A. I.; Moshnikov, V. A., E-mail: vamoshnikov@mail.ru

    Results obtained in the deposition of nanostructured zinc-oxide layers by hydrothermal synthesis as the basic method are presented. The possibility of controlling the structure and morphology of the layers is demonstrated. The important role of the procedure employed to form the nucleating layer is noted. The faceted hexagonal nanoprisms obtained are promising for the fabrication of solar cells based on oxide heterostructures, and aluminum-doped zinc-oxide layers with petal morphology, for the deposition of an antireflection layer. The results are compatible and promising for application in flexible electronics.

  7. Development of Advanced Deposition Technology for Microcrystalline Si Based Solar Cells and Modules: Final Technical Report, 1 May 2002-31 July 2004

    SciTech Connect

    Li, Y. M.

    2004-12-01

    The key objective of this subcontract was to take the first steps to extend the radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) manufacturing technology of Energy Photovoltaics, Inc. (EPV), to the promising field of a-Si/nc-Si solar cell fabrication by demonstrating ''proof-of-concept'' devices of good efficiencies that previously were believed to be unobtainable in single-chamber reactors owing to contamination problems. A complementary goal was to find a new high-rate deposition method that can conceivably be deployed in large PECVD-type reactors. We emphasize that our goal was not to produce 'champion' devices of near-record efficiencies, but rather, to achieve modestly high efficiencies usingmore » a far simpler (cheaper) system, via practical processing methods and materials. To directly attack issues in solar-cell fabrication at EPV, the nc-Si thin films were studied almost exclusively in the p-i-n device configuration (as absorbers or i-layers), not as stand-alone films. Highly efficient, p-i-n type, nc-Si-based solar cells are generally grown on expensive, laboratory superstrates, such as custom ZnO/glass of high texture (granular surface) and low absorption. Also standard was the use of a highly effective back-reflector ZnO/Ag, where the ZnO can be surface-textured for efficient diffuse reflection. The high-efficiency ''champion'' devices made by the PECVD methods were invariably prepared in sophisticated (i.e., expensive), multi-chamber, or at least load-locked deposition systems. The electrode utilization efficiency, defined as the surface-area ratio of the powered electrode to that of the substrates, was typically low at about one (1:1). To evaluate the true potential of nc-Si absorbers for cost-competitive, commercially viable manufacturing of large-area PV modules, we took a more down-to-earth approach, based on our proven production of a-Si PV modules by a massively parallel batch process in single-chamber RF-PECVD systems, to

  8. Bio-based products from solar energy and carbon dioxide.

    PubMed

    Yu, Jian

    2014-01-01

    Producing bio-based products directly from CO₂ and solar energy is a desirable alternative to the conventional biorefining that relies on biomass feedstocks. The production paradigm is based on an artificial photosynthetic system that converts sunlight to electricity and H₂ via water electrolysis. An autotrophic H₂-oxidizing bacterium fixes CO₂ in dark conditions. The assimilated CO₂ is stored in bacterial cells as polyhydroxybutyrate (PHB), from which a range of products can be derived. Compared with natural photosynthesis of a fast-growing cyanobacterium, the artificial photosynthetic system has much higher energy efficiency and productivity of bio-based products. The new technology looks promising because of possible cost reduction in feedstock, equipment, and operation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Adaptive control for solar energy based DC microgrid system development

    NASA Astrophysics Data System (ADS)

    Zhang, Qinhao

    During the upgrading of current electric power grid, it is expected to develop smarter, more robust and more reliable power systems integrated with distributed generations. To realize these objectives, traditional control techniques are no longer effective in either stabilizing systems or delivering optimal and robust performances. Therefore, development of advanced control methods has received increasing attention in power engineering. This work addresses two specific problems in the control of solar panel based microgrid systems. First, a new control scheme is proposed for the microgrid systems to achieve optimal energy conversion ratio in the solar panels. The control system can optimize the efficiency of the maximum power point tracking (MPPT) algorithm by implementing two layers of adaptive control. Such a hierarchical control architecture has greatly improved the system performance, which is validated through both mathematical analysis and computer simulation. Second, in the development of the microgrid transmission system, the issues related to the tele-communication delay and constant power load (CPL)'s negative incremental impedance are investigated. A reference model based method is proposed for pole and zero placements that address the challenges of the time delay and CPL in closed-loop control. The effectiveness of the proposed modeling and control design methods are demonstrated in a simulation testbed. Practical aspects of the proposed methods for general microgrid systems are also discussed.

  10. Organic solar cells based on non-fullerene acceptors

    NASA Astrophysics Data System (ADS)

    Hou, Jianhui; Inganäs, Olle; Friend, Richard H.; Gao, Feng

    2018-02-01

    Organic solar cells (OSCs) have been dominated by donor:acceptor blends based on fullerene acceptors for over two decades. This situation has changed recently, with non-fullerene (NF) OSCs developing very quickly. The power conversion efficiencies of NF OSCs have now reached a value of over 13%, which is higher than the best fullerene-based OSCs. NF acceptors show great tunability in absorption spectra and electron energy levels, providing a wide range of new opportunities. The coexistence of low voltage losses and high current generation indicates that new regimes of device physics and photophysics are reached in these systems. This Review highlights these opportunities made possible by NF acceptors, and also discuss the challenges facing the development of NF OSCs for practical applications.

  11. Triplet Tellurophene-Based Acceptors for Organic Solar Cells.

    PubMed

    Yang, Lei; Gu, Wenxing; Lv, Lei; Chen, Yusheng; Yang, Yufei; Ye, Pan; Wu, Jianfei; Hong, Ling; Peng, Aidong; Huang, Hui

    2018-01-22

    Triplet materials have been employed to achieve high-performing organic solar cells (OSCs) by extending the exciton lifetime and diffusion distances, while the triplet non-fullerene acceptor materials have never been reported for bulk heterojunction OSCs. Herein, for the first time, three triplet molecular acceptors based on tellurophene with different degrees of ring fusing were designed and synthesized for OSCs. Significantly, these molecules have long exciton lifetime and diffusion lengths, leading to efficient power conversion efficiency (7.52 %), which is the highest value for tellurophene-based OSCs. The influence of the extent of ring fusing on molecular geometry and OSCs performance was investigated to show the power conversion efficiencies (PCEs) continuously increased along with increasing the extent of ring fusing. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Distributed modeling of surface solar radiation based on aerosol optical depth and sunshine duration in China

    NASA Astrophysics Data System (ADS)

    Zeng, Xiaofan; Zhao, Na; Ma, Yue

    2018-02-01

    Surface solar radiation, as a major component of energy balance, is an important driving condition for nutrient and energy cycle in the Earth system. The spatial distribution of total solar radiation at 10 km×10 km resolution in China was simulated with Aerosol Optical Depth (AOD) data from remote sensing and observing sunshine hours data from ground meteorological stations based on Geographic Information System (GIS). The results showed that the solar radiation was significantly different in the country, and affected by both sunshine hours and AOD. Sunshine hours are higher in the Northwest than that in the Northeast, but solar radiation is lower because of the higher AOD, especially in autumn and winter. It was suggested that the calculation accuracy of solar radiation was limited if just based on sunshine hours, and AOD can be considered as the influencing factor which would help to improve the simulation accuracy of the total solar radiation and realize the solar radiation distributed simulation.

  13. Understanding chemically processed solar cells based on quantum dots

    NASA Astrophysics Data System (ADS)

    Malgras, Victor; Nattestad, Andrew; Kim, Jung Ho; Dou, Shi Xue; Yamauchi, Yusuke

    2017-12-01

    Photovoltaic energy conversion is one of the best alternatives to fossil fuel combustion. Petroleum resources are now close to depletion and their combustion is known to be responsible for the release of a considerable amount of greenhouse gases and carcinogenic airborne particles. Novel third-generation solar cells include a vast range of device designs and materials aiming to overcome the factors limiting the current technologies. Among them, quantum dot-based devices showed promising potential both as sensitizers and as colloidal nanoparticle films. A good example is the p-type PbS colloidal quantum dots (CQDs) forming a heterojunction with a n-type wide-band-gap semiconductor such as TiO2 or ZnO. The confinement in these nanostructures is also expected to result in marginal mechanisms, such as the collection of hot carriers and generation of multiple excitons, which would increase the theoretical conversion efficiency limit. Ultimately, this technology could also lead to the assembly of a tandem-type cell with CQD films absorbing in different regions of the solar spectrum.

  14. Understanding chemically processed solar cells based on quantum dots

    PubMed Central

    Malgras, Victor; Nattestad, Andrew; Kim, Jung Ho; Dou, Shi Xue; Yamauchi, Yusuke

    2017-01-01

    Abstract Photovoltaic energy conversion is one of the best alternatives to fossil fuel combustion. Petroleum resources are now close to depletion and their combustion is known to be responsible for the release of a considerable amount of greenhouse gases and carcinogenic airborne particles. Novel third-generation solar cells include a vast range of device designs and materials aiming to overcome the factors limiting the current technologies. Among them, quantum dot-based devices showed promising potential both as sensitizers and as colloidal nanoparticle films. A good example is the p-type PbS colloidal quantum dots (CQDs) forming a heterojunction with a n-type wide-band-gap semiconductor such as TiO2 or ZnO. The confinement in these nanostructures is also expected to result in marginal mechanisms, such as the collection of hot carriers and generation of multiple excitons, which would increase the theoretical conversion efficiency limit. Ultimately, this technology could also lead to the assembly of a tandem-type cell with CQD films absorbing in different regions of the solar spectrum. PMID:28567179

  15. Understanding chemically processed solar cells based on quantum dots.

    PubMed

    Malgras, Victor; Nattestad, Andrew; Kim, Jung Ho; Dou, Shi Xue; Yamauchi, Yusuke

    2017-01-01

    Photovoltaic energy conversion is one of the best alternatives to fossil fuel combustion. Petroleum resources are now close to depletion and their combustion is known to be responsible for the release of a considerable amount of greenhouse gases and carcinogenic airborne particles. Novel third-generation solar cells include a vast range of device designs and materials aiming to overcome the factors limiting the current technologies. Among them, quantum dot-based devices showed promising potential both as sensitizers and as colloidal nanoparticle films. A good example is the p-type PbS colloidal quantum dots (CQDs) forming a heterojunction with a n-type wide-band-gap semiconductor such as TiO 2 or ZnO. The confinement in these nanostructures is also expected to result in marginal mechanisms, such as the collection of hot carriers and generation of multiple excitons, which would increase the theoretical conversion efficiency limit. Ultimately, this technology could also lead to the assembly of a tandem-type cell with CQD films absorbing in different regions of the solar spectrum.

  16. Structural and electrical investigations of a-Si:H(i) and a-Si:H(n+) stacked layers for improving the interface and passivation qualities

    NASA Astrophysics Data System (ADS)

    Hsieh, Yu-Lin; Lee, Chien-Chieh; Lu, Chia-Cheng; Fuh, Yiin-Kuen; Chang, Jenq-Yang; Lee, Ju-Yi; Li, Tomi T.

    2017-07-01

    A symmetrically stacked structure [(a-Si:H(n+)/a-Si:H(i)/CZ wafer (n)/a-Si:H(i)/a-Si:H(n+)] was used to optimize the growth process conditions of the n-type hydrogenated amorphous silicon [a-Si:H(n+)] thin films. Here a-Si:H(n+) film was used as back surface field (BSF) layer for the silicon heterojunction solar cell and all stacked films were prepared by conventional radio-frequency plasma-enhanced chemical vapor deposition. The characterizations of the effective carrier lifetime (τeff), electrical and structural properties, as well as correlation with the hydrogen dilution ratio (R=H2/SiH4) were systematically discussed with the emphasis on the effectiveness of the passivation layer using the lifetime tester, spectroscopic ellipsometry, and hall measurement. High quality of a stacked BSF layer (intrinsic/n-type a-Si:H layer) with effective carrier lifetime of 1.8 ms can be consistently obtained. This improved passivation layer can be primarily attributed to the synergy of chemical and field effect to significantly reduce the surface recombination.

  17. A plasticized polymer-electrolyte-based photoelectrochemical solar cell

    SciTech Connect

    Mao, D.; Ibrahim, M.A.; Frank, A.J.

    1998-01-01

    A photoelectrochemical solar cell based on an n-GaAs/polymer-redox-electrolyte junction is reported. Di(ethylene glycol) ethyl ether acrylate containing ferrocene as a redox species and benzoin methyl ether as a photoinitiator is polymerized in situ. Propylene carbonate is used as a plasticizer to improve the conductivity of the polymer redox electrolyte. For thin (1 {micro}m) polymer electrolytes, the series resistance of the cell is negligible. However, the short-circuit photocurrent density of the cell at light intensities above 10 mW/cm{sup 2} is limited by mass transport of redox species within the polymer matrix. At a light intensity of 70 mW/cm{sup 2}, a moderatemore » light-to-electrical energy conversion efficiency (3.1%) is obtained. The interfacial charge-transfer properties of the cell in the dark and under illumination are studied.« less

  18. Power management circuits for self-powered systems based on micro-scale solar energy harvesting

    NASA Astrophysics Data System (ADS)

    Yoon, Eun-Jung; Yu, Chong-Gun

    2016-03-01

    In this paper, two types of power management circuits for self-powered systems based on micro-scale solar energy harvesting are proposed. First, if a solar cell outputs a very low voltage, less than 0.5 V, as in miniature solar cells or monolithic integrated solar cells, such that it cannot directly power the load, a voltage booster is employed to step up the solar cell's output voltage, and then a power management unit (PMU) delivers the boosted voltage to the load. Second, if the output voltage of a solar cell is enough to drive the load, the PMU directly supplies the load with solar energy. The proposed power management systems are designed and fabricated in a 0.18-μm complementary metal-oxide-semiconductor process, and their performances are compared and analysed through measurements.

  19. Present status of solid state photoelectrochemical solar cells and dye sensitized solar cells using PEO-based polymer electrolytes

    NASA Astrophysics Data System (ADS)

    Singh, Pramod Kumar; Nagarale, R. K.; Pandey, S. P.; Rhee, H. W.; Bhattacharya, Bhaskar

    2011-06-01

    Due to energy crises in the future, much effort is being directed towards alternate sources. Solar energy is accepted as a novel substitute for conventional sources of energy. Out of the long list of various types of solar cells available on the market, solid state photoelectrochemical solar cells (SSPECs) and dye sensitized solar cells (DSSCs) are proposed as an alternative to costly crystalline solar cell. This review provides a common platform for SSPECs and DSSCs using polymer electrolyte, particularly on polyethylene oxide (PEO)-based polymer electrolytes. Due to numerous advantageous properties of PEO, it is frequently used as an electrolyte in both SSPECs as well as DSSCs. In DSSCs, so far high efficiency (more than 11%) has been obtained only by using volatile liquid electrolyte, which suffers many disadvantages, such as corrosion, leakage and evaporation. The PEO-based solid polymer proves its importance and could be used to solve the problems stated above. The recent developments in SSPECs and DSSCs using modified PEO electrolytes by adding nano size inorganic fillers, blending with low molecular weight polymers and ionic liquid (IL) are discussed in detail. The role of ionic liquid in modifying the electrical, structural and photoelectrochemical properties of PEO polymer electrolytes is also described.

  20. High temperature solar photon engines. [heat engines for terrestrial and space-based solar power plants

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.; Decher, R.; Mattick, A. T.; Lau, C. V.

    1978-01-01

    High temperature heat engines designed to make maximum use of the thermodynamic potential of concentrated solar radiation are described. Plasmas between 2000 K and 4000 K can be achieved by volumetric absorption of radiation in alkali metal vapors, leading to thermal efficiencies up to 75% for terrestrial solar power plants and up to 50% for space power plants. Two machines capable of expanding hot plasmas using practical technology are discussed. A binary Rankine cycle uses fluid mechanical energy transfer in a device known as the 'Comprex' or 'energy exchanger.' The second machine utilizes magnetohydrodynamics in a Brayton cycle for space applications. Absorption of solar energy and plasma radiation losses are investigated for a solar superheater using potassium vapor.

  1. Ground-based solar astrometric measurements during the PICARD mission

    NASA Astrophysics Data System (ADS)

    Irbah, A.; Meftah, M.; Corbard, T.; Ikhlef, R.; Morand, F.; Assus, P.; Fodil, M.; Lin, M.; Ducourt, E.; Lesueur, P.; Poiet, G.; Renaud, C.; Rouze, M.

    2011-11-01

    PICARD is a space mission developed mainly to study the geometry of the Sun. The satellite was launched in June 2010. The PICARD mission has a ground program which is based at the Calern Observatory (Observatoire de la C^ote d'Azur). It will allow recording simultaneous solar images from ground. Astrometric observations of the Sun using ground-based telescopes need however an accurate modelling of optical e®ects induced by atmospheric turbulence. Previous works have revealed a dependence of the Sun radius measurements with the observation conditions (Fried's parameter, atmospheric correlation time(s) ...). The ground instruments consist mainly in SODISM II, replica of the PICARD space instrument and MISOLFA, a generalized daytime seeing monitor. They are complemented by standard sun-photometers and a pyranometer for estimating a global sky quality index. MISOLFA is founded on the observation of Angle-of-Arrival (AA) °uctuations and allows us to analyze atmospheric turbulence optical e®ects on measurements performed by SODISM II. It gives estimations of the coherence parameters characterizing wave-fronts degraded by the atmospheric turbulence (Fried's parameter, size of the isoplanatic patch, the spatial coherence outer scale and atmospheric correlation times). This paper presents an overview of the ground based instruments of PICARD and some results obtained from observations performed at Calern observatory in 2011.

  2. Monolithic-Structured Single-Layered Textile-Based Dye-Sensitized Solar Cells.

    PubMed

    Yun, Min Ju; Cha, Seung I; Kim, Han Seong; Seo, Seon Hee; Lee, Dong Y

    2016-10-06

    Textile-structured solar cells are frequently discussed in the literature due to their prospective applications in wearable devices and in building integrated solar cells that utilize their flexibility, mechanical robustness, and aesthetic appearance, but the current approaches for textile-based solar cells-including the preparation of fibre-type solar cells woven into textiles-face several difficulties from high friction and tension during the weaving process. This study proposes a new structural concept and fabrication process for monolithic-structured textile-based dye-sensitized solar cells that are fabricated by a process similar to the cloth-making process, including the preparation of wires and yarns that are woven for use in textiles, printed, dyed, and packaged. The fabricated single-layered textile-based dye-sensitized solar cells successfully act as solar cells in our study, even under bending conditions. By controlling the inter-weft spacing and the number of Ti wires for the photoelectrode conductor, we have found that the performance of this type of dye-sensitized solar cell was notably affected by the spacing between photoelectrodes and counter-electrodes, the exposed areas of Ti wires to photoelectrodes, and photoelectrodes' surface morphology. We believe that this study provides a process and concept for improved textile-based solar cells that can form the basis for further research.

  3. High Resolution Observations of Solar Quiescent Prominences with the Hinode Solar Optical Telescope: an Open Challenge to 21st Century Ground-based Solar Telescopes (Invited)

    NASA Astrophysics Data System (ADS)

    Berger, T. E.

    2009-12-01

    The Solar Optical Telescope (SOT) on the Japanese Hinode satellite is a 0.5-meter diameter Gregorian solar telescope in a 600 km Sun-synchronous orbit. The telescope achieves diffraction-limited imaging with no atmospheric seeing in a wavelength range from 380 nm to 660 nm. Using both the Broadband Filter Imager (BFI) Ca II H-line channel at 389.6 nm and the tunable Narrowband Filter Imager (NFI) H-alpha channel at 656.3 nm we have observed many quiescent solar prominences since the satellite launch in September 2006. The excellent optical quality and low scattering of the SOT telescope combined with the lack of atmospheric scattering and seeing enables us to capture multi-hour diffraction-limited movies of quiescent prominences above the limb that achieve 200 km spatial resolution and 15--30 second temporal resolution. These SOT observations have led to the discovery of new flows in the solar outer atmosphere in the form of buoyant small-scale (2--6 Mm) plumes and large-scale (10--50 Mm) "bubbles" or arches that originate below quiescent prominences and rise with speeds of 10--30 km/sec to heights of 10--30+ Mm above the solar limb. In this talk we review the kinematic properties of these new flows in combination with the long-observed filamentary downflows to show that quisecent prominences are not magnetostatic structures "suspended against gravity" but are rather entirely dynamic structures in which mass is continually drained in the downflows while being resupplied largely by condensation from the coronal cavity above and episodic buoyant flows from below. The Hinode/SOT instrument has definitively shown the value of flying high-resolution visible-light solar telescopes in space by acheiving in its first six months what had been a long-standing goal of ground-based solar prominence research for the past 50 years. However many key quiescent prominence characteristics cannot be measured by the limited instrumentation on the Hinode satellite. Primary among these

  4. High performance hybrid silicon micropillar solar cell based on light trapping characteristics of Cu nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhang, Yulong; Fan, Zhiqiang; Zhang, Weijia; Ma, Qiang; Jiang, Zhaoyi; Ma, Denghao

    2018-05-01

    High performance silicon combined structure (micropillar with Cu nanoparticles) solar cell has been synthesized from N-type silicon substrates based on the micropillar array. The combined structure solar cell exhibited higher short circuit current rather than the silicon miropillar solar cell, which the parameters of micropillar array are the same. Due to the Cu nanoparticles were decorated on the surface of silicon micropillar array, the photovoltaic properties of cells have been improved. In addition, the optimal efficiency of 11.5% was measured for the combined structure solar cell, which is better than the silicon micropillar cell.

  5. The SAMEX Vector Magnetograph: A Design Study for a Space-Based Solar Vector Magnetograph

    NASA Technical Reports Server (NTRS)

    Hagyard, M. J.; Gary, G. A.; West, E. A.

    1988-01-01

    This report presents the results of a pre-phase A study performed by the Marshall Space Flight Center (MSFC) for the Air Force Geophysics Laboratory (AFGL) to develop a design concept for a space-based solar vector magnetograph and hydrogen-alpha telescope. These are two of the core instruments for a proposed Air Force mission, the Solar Activities Measurement Experiments (SAMEX). This mission is designed to study the processes which give rise to activity in the solar atmosphere and to develop techniques for predicting solar activity and its effects on the terrestrial environment.

  6. An IBM PC-based math model for space station solar array simulation

    NASA Technical Reports Server (NTRS)

    Emanuel, E. M.

    1986-01-01

    This report discusses and documents the design, development, and verification of a microcomputer-based solar cell math model for simulating the Space Station's solar array Initial Operational Capability (IOC) reference configuration. The array model is developed utilizing a linear solar cell dc math model requiring only five input parameters: short circuit current, open circuit voltage, maximum power voltage, maximum power current, and orbit inclination. The accuracy of this model is investigated using actual solar array on orbit electrical data derived from the Solar Array Flight Experiment/Dynamic Augmentation Experiment (SAFE/DAE), conducted during the STS-41D mission. This simulator provides real-time simulated performance data during the steady state portion of the Space Station orbit (i.e., array fully exposed to sunlight). Eclipse to sunlight transients and shadowing effects are not included in the analysis, but are discussed briefly. Integrating the Solar Array Simulator (SAS) into the Power Management and Distribution (PMAD) subsystem is also discussed.

  7. High-Efficiency Flexible Solar Cells Based on Organometal Halide Perovskites.

    PubMed

    Wang, Yuming; Bai, Sai; Cheng, Lu; Wang, Nana; Wang, Jianpu; Gao, Feng; Huang, Wei

    2016-06-01

    Flexible and light-weight solar cells are important because they not only supply power to wearable and portable devices, but also reduce the transportation and installation cost of solar panels. High-efficiency organometal halide perovskite solar cells can be fabricated by a low-temperature solution process, and hence are promising for flexible-solar-cell applications. Here, the development of perovskite solar cells is briefly discussed, followed by the merits of organometal halide perovskites as promising candidates as high-efficiency, flexible, and light-weight photovoltaic materials. Afterward, recent developments of flexible solar cells based on perovskites are reviewed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. A solar receiver-storage modular cascade based on porous ceramic structures for hybrid sensible/thermochemical solar energy storage

    NASA Astrophysics Data System (ADS)

    Agrafiotis, Christos; de Oliveira, Lamark; Roeb, Martin; Sattler, Christian

    2016-05-01

    The current state-of-the-art solar heat storage concept in air-operated Solar Tower Power Plants is to store the solar energy provided during on-sun operation as sensible heat in porous solid materials that operate as recuperators during off-sun operation. The technology is operationally simple; however its storage capacity is limited to 1.5 hours. An idea for extending this capacity is to render this storage concept from "purely" sensible to "hybrid" sensible/ thermochemical one, via coating the porous heat exchange modules with oxides of multivalent metals for which their reduction/oxidation reactions are accompanied by significant heat effects, or by manufacturing them entirely of such oxides. In this way solar heat produced during on-sun operation can be used (in addition to sensibly heating the porous solid) to power the endothermic reduction of the oxide from its state with the higher metal valence to that of the lower; the thermal energy can be entirely recovered by the reverse exothermic oxidation reaction (in addition to sensible heat) during off-sun operation. Such sensible and thermochemical storage concepts were tested on a solar-irradiated receiver- heat storage module cascade for the first time. Parametric studies performed so far involved the comparison of three different SiC-based receivers with respect to their capability of supplying solar-heated air at temperatures sufficient for the reduction of the oxides, the effect of air flow rate on the temperatures achieved within the storage module, as well as the comparison of different porous storage media made of cordierite with respect to their sensible storage capacity.

  9. Beamed Energy and the Economics of Space Based Solar Power

    NASA Astrophysics Data System (ADS)

    Keith Henson, H.

    2010-05-01

    For space based solar power to replace fossil fuel, it must sell for 1-2 cents per kWh. To reach this sales price requires a launch cost to GEO of ˜100/kg. Proposed to reach this cost figure at 100 tonne/hour are two stages to GEO where a Skylon-rocket-plane first stage provides five km/sec and a laser stage provides 6.64 km/sec. The combination appears to reduce the cost to GEO to under 100/kg at a materials flow rate of ˜1 million tonnes per year, enough to initially construct 200 GW per year of power satellites. An extended Pro Forma business case indicates that peak investment to profitability might be ˜65 B. Over a 25-year period, production rises to two TW per year to undercut and replace most other sources of energy. Energy on this scale solves other supply problems such as water and liquid fuels. It could even allow removal of CO2 from the air and storage of carbon as synthetic oil in empty oil fields.

  10. Tuning pentacene based dye-sensitized solar cells.

    PubMed

    Kunzmann, Andreas; Gruber, Marco; Casillas, Rubén; Tykwinski, Rik R; Costa, Rubén D; Guldi, Dirk M

    2018-05-10

    We report on the synthesis, as well as photophysical and electrochemical characterization of a new family of pentacene derivatives, which are applied in n-type dye-sensitized solar cells (DSSCs). As far as the molecular structure of the pentacene is concerned, the synthetic design focuses on cyano acrylic tethered at the 13-position of the pentacene chromophore. The electrolyte composition features increasing amounts of Li+ ions as an additive. In general, the increase of Li+ concentrations extrinsically reduces the quasi Fermi level of the photoanode and as such facilitates the electron injection process. We demonstrate that pentacene derivatives give rise to a unique charge injection process, which is controlled by the positioning of the quasi Fermi level energies as a function of the Li+ concentration. As a result of the enhanced charge injection, device efficiencies as high as 1.5% are achieved, representing a 3-fold increase from previously reported efficiencies in pentacene-based DSSCs. These findings are supported by device analysis in combination with transient absorption and electrochemical impedance spectroscopy assays.

  11. Wireless electricity (Power) transmission using solar based power satellite technology

    NASA Astrophysics Data System (ADS)

    Maqsood, M.; Nauman Nasir, M.

    2013-06-01

    In the near future due to extensive use of energy, limited supply of resources and the pollution in environment from present resources e.g. (wood, coal, fossil fuel) etc, alternative sources of energy and new ways to generate energy which are efficient, cost effective and produce minimum losses are of great concern. Wireless electricity (Power) transmission (WET) has become a focal point as research point of view and nowadays lies at top 10 future hot burning technologies that are under research these days. In this paper, we present the concept of transmitting power wirelessly to reduce transmission and distribution losses. The wired distribution losses are 70 - 75% efficient. We cannot imagine the world without electric power which is efficient, cost effective and produce minimum losses is of great concern. This paper tells us the benefits of using WET technology specially by using Solar based Power satellites (SBPS) and also focuses that how we make electric system cost effective, optimized and well organized. Moreover, attempts are made to highlight future issues so as to index some emerging solutions.

  12. Adaptive sensor-based ultra-high accuracy solar concentrator tracker

    NASA Astrophysics Data System (ADS)

    Brinkley, Jordyn; Hassanzadeh, Ali

    2017-09-01

    Conventional solar trackers use information of the sun's position, either by direct sensing or by GPS. Our method uses the shading of the receiver. This, coupled with nonimaging optics design allows us to achieve ultra-high concentration. Incorporating a sensor based shadow tracking method with a two stage concentration solar hybrid parabolic trough allows the system to maintain high concentration with acute accuracy.

  13. Optical design of a high-power LED-based solar simulator

    NASA Astrophysics Data System (ADS)

    Toro-Betancur, Veronica; Velásquez-López, Alejandro; Velásquez, David; Acevedo-Gómez, David

    2016-04-01

    The optical design of a High-Power LED based Solar Simulator was made in order to reach the AM1.5G spectrum standards. An optical model of the light emitted by the LEDs was made and used for spectral intensities calculations and the light intensity uniformity was optimized. A class AAA solar simulator was designed using a hexagonal LED distribution.

  14. The status of lightweight photovoltaic space array technology based on amorphous silicon solar cells

    NASA Astrophysics Data System (ADS)

    Hanak, J. J.; Kaschmitter, J. L.

    1991-05-01

    An ultralight, flexible photovoltaic (PV) array of amorphous silicon (a-Si) has been identified as a potential low-cost power source for small satellites. We have conducted a survey of the status of the a-Si PV array technology with respect to present and future performance, availability, cost and risks. For existing, experimental array 'blankets' made of commercial cell material, utilizing metal foil substrates, the BOL performance at AM0 and 35 C includes total power up to 200 W, power per area of 64 W/sq m and power per weight of 258 W/kg. Doubling of power per weight occurs when polyimide substrates are used. Estimated EOL power output after 10 years in a nominal low-earth orbit would be 80 percent of BOL, the degradation being due to largely light-induced effects (minus 10 to minus 15 percent) and in part (minus 5 percent) to space radiation. Predictions for the year 1995 for flexible PV arrays, made on the basis of published results for rigid a-Si modules, indicate EOL power output per area and per weight of 105 W/sq m and 400 W/kg, respectively, while predictions for the late 1990s based on existing US national PV program goals indicate EOL values of 157 W/sq m and 600 W/kg. cost estimates by vendors for 200 W ultralight arrays in volume of over 1000 units range from $100/watt to $125/watt. Identified risks include the lack of flexible, space compatible encapsulant, the lack of space qualification effort, recent partial or full acquisitions of US manufacturers of a-Si cells by foreign firms, and the absence of a national commitment for a long-range development program toward developing of this important power source for space. One new US developer has emerged as a future potential supplier of a-Si PV devices on thin, polyimide substrates.

  15. Window structure for passivating solar cells based on gallium arsenide

    NASA Technical Reports Server (NTRS)

    Barnett, Allen M. (Inventor)

    1985-01-01

    Passivated gallium arsenide solar photovoltaic cells with high resistance to moisture and oxygen are provided by means of a gallium arsenide phosphide window graded through its thickness from arsenic rich to phosphorus rich.

  16. Long-Term Solar and Cosmic Radiation Data Bases

    DTIC Science & Technology

    1991-01-01

    determine the magnitude of the variations in the cosmic ray intensity caused by solar activity. Neutron monitors, with their much lower energy threshold...expression that neutron monitors are sensors on spacecraft EARTH. Here we will consider cosmic ray detectors to measure two components of cosmic ...A comparison with the solar cycle as illustrated by the sunspot number in Fig. 1. shows that the maximum cosmic ray intensity occurs near sunspot

  17. A Raster Based Approach To Solar Pressure Modeling

    NASA Technical Reports Server (NTRS)

    Wright, Theodore

    2014-01-01

    The impact of photons upon a spacecraft introduces small forces and moments. The magnitude and direction of the forces depend on the material properties of the spacecraft components being illuminated. Which components are being lit depends on the orientation of the craft with respect to the Sun as well as the gimbal angles for any significant moving external parts (solar arrays, typically). Some components may shield others from the Sun.To determine solar pressure in the presence overlapping components, a 3D model can be used to determine which components are illuminated. A view (image) of the model as seen from the Sun shows the only contributors to solar pressure. This image can be decomposed into pixels, each of which can be treated as a non-overlapping flat plate as far as solar pressure calculations are concerned. The sums of the pressures and moments on these plates approximate the solar pressure and moments on the entire vehicle.The image rasterization technique can also be used to compute other spacecraft attributes that are dependent on attitude and geometry, including solar array power generation capability and free molecular flow drag.

  18. Visible-blind and solar-blind ultraviolet photodiodes based on (In{sub x}Ga{sub 1−x}){sub 2}O{sub 3}

    SciTech Connect

    Zhang, Zhipeng; Wenckstern, Holger von; Lenzner, Jörg

    UV and deep-UV selective photodiodes from visible-blind to solar-blind were realized based on a Si-doped (In{sub x}Ga{sub 1–x}){sub 2}O{sub 3} thin film with a monotonic lateral variation of 0.0035 < x < 0.83. Such layer was deposited by employing a continuous composition spread approach relying on the ablation of a single segmented target in pulsed-laser deposition. The photo response signal is provided from a metal-semiconductor-metal structure upon backside illumination. The absorption onset was tuned from 4.83 to 3.22 eV for increasing x. Higher responsivities were observed for photodiodes fabricated from indium-rich part of the sample, for which an internal gain mechanism could be identified.

  19. A Python-based interface to examine motions in time series of solar images

    NASA Astrophysics Data System (ADS)

    Campos-Rozo, J. I.; Vargas Domínguez, S.

    2017-10-01

    Python is considered to be a mature programming language, besides of being widely accepted as an engaging option for scientific analysis in multiple areas, as will be presented in this work for the particular case of solar physics research. SunPy is an open-source library based on Python that has been recently developed to furnish software tools to solar data analysis and visualization. In this work we present a graphical user interface (GUI) based on Python and Qt to effectively compute proper motions for the analysis of time series of solar data. This user-friendly computing interface, that is intended to be incorporated to the Sunpy library, uses a local correlation tracking technique and some extra tools that allows the selection of different parameters to calculate, vizualize and analyze vector velocity fields of solar data, i.e. time series of solar filtergrams and magnetograms.

  20. Solar energy converters based on multi-junction photoemission solar cells.

    PubMed

    Tereshchenko, O E; Golyashov, V A; Rodionov, A A; Chistokhin, I B; Kislykh, N V; Mironov, A V; Aksenov, V V

    2017-11-23

    Multi-junction solar cells with multiple p-n junctions made of different semiconductor materials have multiple bandgaps that allow reducing the relaxation energy loss and substantially increase the power-conversion efficiency. The choice of materials for each sub-cell is very limited due to the difficulties in extracting the current between the layers caused by the requirements for lattice- and current-matching. We propose a new vacuum multi-junction solar cell with multiple p-n junctions separated by vacuum gaps that allow using different semiconductor materials as cathode and anode, both activated to the state of effective negative electron affinity (NEA). In this work, the compact proximity focused vacuum tube with the GaAs(Cs,O) photocathode and AlGaAs/GaAs-(Cs,O) anode with GaAs quantum wells (QWs) is used as a prototype of a vacuum single-junction solar cell. The photodiode with the p-AlGaAs/GaAs anode showed the spectral power-conversion efficiency of about 1% at V bias  = 0 in transmission and reflection modes, while, at V bias  = 0.5 V, the efficiency increased up to 10%. In terms of energy conservation, we found the condition at which the energy cathode-to-anode transition was close to 1. Considering only the energy conservation part, the NEA-cell power-conversion efficiency can rich a quantum yield value which is measured up to more than 50%.

  1. Fast determination of the current loss mechanisms in textured crystalline Si-based solar cells

    NASA Astrophysics Data System (ADS)

    Nakane, Akihiro; Fujimoto, Shohei; Fujiwara, Hiroyuki

    2017-11-01

    A quite general device analysis method that allows the direct evaluation of optical and recombination losses in crystalline silicon (c-Si)-based solar cells has been developed. By applying this technique, the current loss mechanisms of the state-of-the-art solar cells with ˜20% efficiencies have been revealed. In the established method, the optical and electrical losses are characterized from the analysis of an experimental external quantum efficiency (EQE) spectrum with very low computational cost. In particular, we have performed the EQE analyses of textured c-Si solar cells by employing the experimental reflectance spectra obtained directly from the actual devices while using flat optical models without any fitting parameters. We find that the developed method provides almost perfect fitting to EQE spectra reported for various textured c-Si solar cells, including c-Si heterojunction solar cells, a dopant-free c-Si solar cell with a MoOx layer, and an n-type passivated emitter with rear locally diffused solar cell. The modeling of the recombination loss further allows the extraction of the minority carrier diffusion length and surface recombination velocity from the EQE analysis. Based on the EQE analysis results, the current loss mechanisms in different types of c-Si solar cells are discussed.

  2. Radiative efficiency of lead iodide based perovskite solar cells

    PubMed Central

    Tvingstedt, Kristofer; Malinkiewicz, Olga; Baumann, Andreas; Deibel, Carsten; Snaith, Henry J.; Dyakonov, Vladimir; Bolink, Henk J.

    2014-01-01

    The maximum efficiency of any solar cell can be evaluated in terms of its corresponding ability to emit light. We herein determine the important figure of merit of radiative efficiency for Methylammonium Lead Iodide perovskite solar cells and, to put in context, relate it to an organic photovoltaic (OPV) model device. We evaluate the reciprocity relation between electroluminescence and photovoltaic quantum efficiency and conclude that the emission from the perovskite devices is dominated by a sharp band-to-band transition that has a radiative efficiency much higher than that of an average OPV device. As a consequence, the perovskite have the benefit of retaining an open circuit voltage ~0.14 V closer to its radiative limit than the OPV cell. Additionally, and in contrast to OPVs, we show that the photoluminescence of the perovskite solar cell is substantially quenched under short circuit conditions in accordance with how an ideal photovoltaic cell should operate. PMID:25317958

  3. Robustness up to 400°C of the passivation of c-Si by p-type a-Si:H thanks to ion implantation

    NASA Astrophysics Data System (ADS)

    Defresne, A.; Plantevin, O.; Roca i Cabarrocas, Pere

    2016-12-01

    Heterojunction solar cells based on crystalline silicon (c-Si) passivated by hydrogenated amorphous silicon (a-Si:H) thin films are one of the most promising architectures for high energy conversion efficiency. Indeed, a-Si:H thin films can passivate both p-type and n-type wafers and can be deposited at low temperature (<200°C) using PECVD. However, such passivation layers, in particular p-type a-Si:H, show a dramatic degradation in passivation quality above 200°C. Yet, annealing at 300 - 400°C the TCO layer and metallic contacts is highly desirable to reduce the contact resistance as well as the TCO optical absorption. In this work, we show that as expected, ion implantation (5 - 30 keV) introduces defects at the c-Si/a-Si:H interface which strongly degrade the effective lifetime, down to a few micro-seconds. However, the passivation quality can be restored and lifetime values can be improved up to 2 ms over the initial value with annealing. We show here that effective lifetimes above 1 ms can be maintained up to 380°C, opening up the possibility for higher process temperatures in silicon heterojunction device fabrication.

  4. Solar concentrator technology development for space based applications, volume 1

    NASA Technical Reports Server (NTRS)

    Pintz, A.; Castle, C. H.; Reimer, R. R.

    1992-01-01

    Thermoelectric conversion using a radio-isotope heat source has been used where outer planetary space craft are too far away for absorbing significant solar energy. Solar dynamic power (SDP) conversion is one technology that offers advantages for applications within the inner planet region. Since SDP conversion efficiency can be 2 to 3 times higher than photovoltaic, the collecting surfaces are much reduced in area and therefore lighter. This becomes an advantage in allocating more weight to launched payloads. A second advantage results for low earth orbit applications. The reduced area results in lower drag forces on the spacecraft and requires less reboost propellant to maintain orbit. A third advantage occurs because of the sun-to-shade cycling while in earth orbit. Photovoltaic systems require batteries to store energy for use when in the shade, and battery life for periods of 10 to 15 years is not presently achievable. For these reasons the Solar Dynamics and Thermal Systems Branch at NASA LeRC has funded work in developing SDP systems. The generic SDP system uses a large parabolic solar concentrator to focus solar energy onto a power conversion device. The concentrators are large areas and must therefore be efficient and have low specific weights. Yet these surfaces must be precise and capable of being stowed in a launch vehicle and then deployed and sometimes unfurled in space. There are significant technical challenges in engineering such structures, and considerable investigation has been made to date. This is the first of two volumes reporting on the research done by the Advanced Manufacturing Center at Cleveland State University to assist NASA LeRC in evaluating this technology. The objective of the grant was to restore the solar concentrator development technology of the 1960s while improving it with advances that have occurred since then. This report summarizes the work done from January 1989 through December 1991.

  5. Solar concentrator technology development for space based applications, volume 2

    NASA Technical Reports Server (NTRS)

    Pintz, A.; Castle, C. H.; Reimer, R. R.

    1992-01-01

    Thermoelectric conversion using a radio-isotope heat source has been used where outer planetary space craft are too far away for absorbing significant solar energy. Solar dynamic power (SDP) conversion is one technology that offers advantages for applications within the inner planet region. Since SDP conversion efficiency can be 2 to 3 times higher than photovoltaic, the collecting surfaces are much reduced in area and therefore lighter. This becomes an advantage in allocating more weight to launched payloads. A second advantage results for low earth orbit applications. The reduced area results in lower drag forces on the spacecraft and requires less reboost propellant to maintain orbit. A third advantage occurs because of the sun-to-shade cycling while in earth orbit. Photovoltaic systems require batteries to store energy for use when in the shade, and battery life for periods of 10 to 15 years is not presently achievable. For these reasons the Solar Dynamics and Thermal Systems Branch at NASA LeRC has funded work in developing SDP systems. The generic SDP system uses a large parabolic solar concentrator to focus solar energy onto a power conversion device. The concentrators are large areas and must therefore be efficient and have low specific weights. Yet these surfaces must be precise and capable of being stowed in a launch vehicle and then deployed and sometimes unfurled in space. There are significant technical challenges in engineering such structures, and considerable investigation has been made to date. This is the second of two volumes reporting on the research done by the Advanced Manufacturing Center at Cleveland State University to assist NASA LeRC in evaluating this technology. This volume includes the appendices of selected data sets, drawings, and procedures. The objective of the grant was to restore the solar concentrator development technology of the 1960s while improving it with advances that have occurred since then. This report summarizes the

  6. Development of a CCD based solar speckle imaging system

    NASA Astrophysics Data System (ADS)

    Nisenson, Peter; Stachnik, Robert V.; Noyes, Robert W.

    1986-02-01

    A program to develop software and hardware for the purpose of obtaining high angular resolution images of the solar surface is described. The program included the procurement of a Charge Coupled Devices imaging system; an extensive laboratory and remote site testing of the camera system; the development of a software package for speckle image reconstruction which was eventually installed and tested at the Sacramento Peak Observatory; and experiments of the CCD system (coupled to an image intensifier) for low light level, narrow spectral band solar imaging.

  7. A base-metal conductor system for silicon solar cells

    NASA Technical Reports Server (NTRS)

    Coleman, M. G.; Pryor, R. A.; Sparks, T. G.

    1980-01-01

    Solder, copper, and silver are evaluated as conductor layer metals for silicon solar cell metallization on the basis of metal price stability and reliability under operating conditions. Due to its properties and cost, copper becomes an attractive candidate for the conductor layer. It is shown that nickel operates as an excellent diffusion barrier between copper and silicon while simultaneously serving as an electrical contact and mechanical contact to silicon. The nickel-copper system may be applied to the silicon by plating techniques utilizing a variety of plating bath compositions. Solar cells having excellent current-voltage characteristics are fabricated to demonstrate the nickel-copper metallization system.

  8. Dye-sensitized solar cells based on purple corn sensitizers

    NASA Astrophysics Data System (ADS)

    Phinjaturus, Kawin; Maiaugree, Wasan; Suriharn, Bhalang; Pimanpaeng, Samuk; Amornkitbamrung, Vittaya; Swatsitang, Ekaphan

    2016-09-01

    Natural dye extracted from husk, cob and silk of purple corn, were used for the first time as photosensitizers in dye sensitized solar cells (DSSCs). The dye sensitized solar cells fabrication process has been optimized in terms of solvent extraction. The resulting maximal efficiency of 1.06% was obtained from purple corn husk extracted by acetone. The ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and incident photon-to-current efficiency (IPCE) were employed to characterize the natural dye and the DSSCs.

  9. To probe the equivalence and opulence of nanocrystal and nanotube based dye-sensitized solar cells

    SciTech Connect

    Jyoti, Divya, E-mail: divyabathla17@gmail.com; Mohan, Devendra

    2016-05-06

    Dye-Sensitized solar cells based on TiO{sub 2} nanocrystal and TiO{sub 2} nanotubes have been fabricated by a simple sol-gel hydrothermal process and their performances have been compared. Current density and voltage (JV) characteristics and incident photon to current conversion efficiency (IPCE) plots have been set as criterion to check which one is better as a photoanode candidate in dye-sensitized solar cell. It has been observed that although open circuit voltage values for both type of cells do not differ much still, nanotube based dye-sensitized solar cells are more successful having an efficiency value of 7.28%.

  10. Space-based solar power conversion and delivery systems study. Volume 4: Energy conversion systems studies

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Solar cells and optical configurations for the SSPS were examined. In this task, three specific solar cell materials were examined: single crystal silicon, single crystal gallium arsenide, and polycrystalline cadmium sulfide. The comparison of the three different cells on the basis of a subsystem parametric cost per kW of SSPS-generated power at the terrestrial utility interface showed that gallium arsenide was the most promising solar cell material at high concentration ratios. The most promising solar cell material with no concentration, was dependent upon the particular combination of parameters representing cost, mass and performance that were chosen to represent each cell in this deterministic comparative analysis. The potential for mass production, based on the projections of the present state-of-the-art would tend to favor cadmium sulfide in lieu of single crystal silicon or gallium arsenide solar cells.

  11. Space-Based Solar Power Conversion and Delivery Systems Study. Volume 1: Executive Summary

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The research concerning space-based solar power conversion and delivery systems is summarized. The potential concepts for a photovoltaic satellite solar power system was studied with emphasis on ground output power levels of 5,000 MW and 10,000 MW. A power relay satellite, and certain aspects of the economics of these systems were also studied. A second study phase examined in greater depth the technical and economic aspects of satellite solar power systems. Throughout this study, the focus was on the economics of satellite solar power. The results indicate technical feasibility of the concept, and provide a preliminary economic justification for the first phase of a substantial development program. A development program containing test satellites is recommended. Also, development of alternative solar cell materials (other than silicon) is recommended.

  12. Quantum-Dot-Based Solar Cells: Recent Advances, Strategies, and Challenges.

    PubMed

    Kim, Mee Rahn; Ma, Dongling

    2015-01-02

    Among next-generation photovoltaic systems requiring low cost and high efficiency, quantum dot (QD)-based solar cells stand out as a very promising candidate because of the unique and versatile characteristics of QDs. The past decade has already seen rapid conceptual and technological advances on various aspects of QD solar cells, and diverse opportunities, which QDs can offer, predict that there is still ample room for further development and breakthroughs. In this Perspective, we first review the attractive advantages of QDs, such as size-tunable band gaps and multiple exciton generation (MEG), beneficial to solar cell applications. We then analyze major strategies, which have been extensively explored and have largely contributed to the most recent and significant achievements in QD solar cells. Finally, their high potential and challenges are discussed. In particular, QD solar cells are considered to hold immense potential to overcome the theoretical efficiency limit of 31% for single-junction cells.

  13. Final Environmental Assessment: Solar Panel Systems at Joint Base McGuire-Dix-Lakehurst New Jersey

    DTIC Science & Technology

    2012-03-01

    FINAL ENVIRONMENTAL ASSESSMENT Solar Panel Systems at Joint Base McGuire-Dix-Lakehurst, New Jersey MARCH 2012...Final Environmental Assessment : Solar Panel Systems at Joint Base McGuire-Dix-Lakehurst New Jersey 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Purpose Finding of No Significant Impact (FONSI) Environmental Assessment (EA

  14. The Simulation of the Recharging Method Based on Solar Radiation for an Implantable Biosensor.

    PubMed

    Li, Yun; Song, Yong; Kong, Xianyue; Li, Maoyuan; Zhao, Yufei; Hao, Qun; Gao, Tianxin

    2016-09-10

    A method of recharging implantable biosensors based on solar radiation is proposed. Firstly, the models of the proposed method are developed. Secondly, the recharging processes based on solar radiation are simulated using Monte Carlo (MC) method and the energy distributions of sunlight within the different layers of human skin have been achieved and discussed. Finally, the simulation results are verified experimentally, which indicates that the proposed method will contribute to achieve a low-cost, convenient and safe method for recharging implantable biosensors.

  15. Tracking Solar Type II Bursts with Space Based Radio Interferometers

    NASA Astrophysics Data System (ADS)

    Hegedus, Alexander M.; Kasper, Justin C.; Manchester, Ward B.

    2018-06-01

    The Earth’s Ionosphere limits radio measurements on its surface, blocking out any radiation below 10 MHz. Valuable insight into many astrophysical processes could be gained by having a radio interferometer in space to image the low frequency window for the first time. One application is observing type II bursts tracking solar energetic particle acceleration in Coronal Mass Ejections (CMEs). In this work we create a simulated data processing pipeline for several space based radio interferometer (SBRI) concepts and evaluate their performance in the task of localizing these type II bursts.Traditional radio astronomy software is hard coded to assume an Earth based array. To circumvent this, we manually calculate the antenna separations and insert them along with the simulated visibilities into a CASA MS file for analysis. To create the realest possible virtual input data, we take a 2-temperature MHD simulation of a CME event, superimpose realistic radio emission models from the CME-driven shock front, and propagate the signal through simulated SBRIs. We consider both probabilistic emission models derived from plasma parameters correlated with type II bursts, and analytical emission models using plasma emission wave interaction theory.One proposed SBRI is the pathfinder mission SunRISE, a 6 CubeSat interferometer to circle the Earth in a GEO graveyard orbit. We test simulated trajectories of SunRISE and image what the array recovers, comparing it to the virtual input. An interferometer on the lunar surface would be a stable alternative that avoids noise sources that affect orbiting arrays, namely the phase noise from positional uncertainty and atmospheric 10s-100s kHz noise. Using Digital Elevation Models from laser altimeter data, we test different sets of locations on the lunar surface to find near optimal configurations for tracking type II bursts far from the sun. Custom software is used to model the response of different array configurations over the lunar year

  16. A Si nanocube array polarizer

    NASA Astrophysics Data System (ADS)

    Chen, Linghua; Jiang, Yingjie; Xing, Li; Yao, Jun

    2017-10-01

    We have proposed a full dielectric (silicon) nanocube array polarizer based on a silicon dioxide substrate. Each polarization unit column includes a plurality of equal spaced polarization units. By optimizing the length, the width, the height of the polarization units and the center distance of adjacent polarization unit (x direction and y direction), an extinction ratio (ER) of higher than 25dB was obtained theoretically when the incident light wavelength is 1550nm. while for applications of most polarization optical elements, ER above 10dB is enough. With this condition, the polarizer we designed can work in a wide wavelength range from 1509.31nm to 1611.51nm. Compared with the previous polarizer, we have introduced a polarizer which is a full dielectric device, which solves the problems of low efficiency caused by Ohmic loss and weak coupling. Furthermore, compared with the existing optical polarizers, our polarizer has the advantages of thin thickness, small size, light weight, and low processing difficulty, which is in line with the future development trend of optical elements.

  17. Toward Cost-Effective Manufacturing of Silicon Solar Cells: Electrodeposition of High-Quality Si Films in a CaCl2 -based Molten Salt.

    PubMed

    Yang, Xiao; Ji, Li; Zou, Xingli; Lim, Taeho; Zhao, Ji; Yu, Edward T; Bard, Allen J

    2017-11-20

    Electrodeposition of Si films from a Si-containing electrolyte is a cost-effective approach for the manufacturing of solar cells. Proposals relying on fluoride-based molten salts have suffered from low product quality due to difficulties in impurity control. Here we demonstrate the successful electrodeposition of high-quality Si films from a CaCl 2 -based molten salt. Soluble Si IV -O anions generated from solid SiO 2 are electrodeposited onto a graphite substrate to form a dense film of crystalline Si. Impurities in the deposited Si film are controlled at low concentrations (both B and P are less than 1 ppm). In the photoelectrochemical measurements, the film shows p-type semiconductor character and large photocurrent. A p-n junction fabricated from the deposited Si film exhibits clear photovoltaic effects. This study represents the first step to the ultimate goal of developing a cost-effective manufacturing process for Si solar cells based on electrodeposition. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. High efficiency silicon solar cell based on asymmetric nanowire.

    PubMed

    Ko, Myung-Dong; Rim, Taiuk; Kim, Kihyun; Meyyappan, M; Baek, Chang-Ki

    2015-07-08

    Improving the efficiency of solar cells through novel materials and devices is critical to realize the full potential of solar energy to meet the growing worldwide energy demands. We present here a highly efficient radial p-n junction silicon solar cell using an asymmetric nanowire structure with a shorter bottom core diameter than at the top. A maximum short circuit current density of 27.5 mA/cm(2) and an efficiency of 7.53% were realized without anti-reflection coating. Changing the silicon nanowire (SiNW) structure from conventional symmetric to asymmetric nature improves the efficiency due to increased short circuit current density. From numerical simulation and measurement of the optical characteristics, the total reflection on the sidewalls is seen to increase the light trapping path and charge carrier generation in the radial junction of the asymmetric SiNW, yielding high external quantum efficiency and short circuit current density. The proposed asymmetric structure has great potential to effectively improve the efficiency of the SiNW solar cells.

  19. PSO Based PI Controller Design for a Solar Charger System

    PubMed Central

    Yau, Her-Terng; Lin, Chih-Jer; Liang, Qin-Cheng

    2013-01-01

    Due to global energy crisis and severe environmental pollution, the photovoltaic (PV) system has become one of the most important renewable energy sources. Many previous studies on solar charger integrated system only focus on load charge control or switching Maximum Power Point Tracking (MPPT) and charge control modes. This study used two-stage system, which allows the overall portable solar energy charging system to implement MPPT and optimal charge control of Li-ion battery simultaneously. First, this study designs a DC/DC boost converter of solar power generation, which uses variable step size incremental conductance method (VSINC) to enable the solar cell to track the maximum power point at any time. The voltage was exported from the DC/DC boost converter to the DC/DC buck converter, so that the voltage dropped to proper voltage for charging the battery. The charging system uses constant current/constant voltage (CC/CV) method to charge the lithium battery. In order to obtain the optimum PI charge controller parameters, this study used intelligent algorithm to determine the optimum parameters. According to the simulation and experimental results, the control parameters resulted from PSO have better performance than genetic algorithms (GAs). PMID:23766713

  20. PSO based PI controller design for a solar charger system.

    PubMed

    Yau, Her-Terng; Lin, Chih-Jer; Liang, Qin-Cheng

    2013-01-01

    Due to global energy crisis and severe environmental pollution, the photovoltaic (PV) system has become one of the most important renewable energy sources. Many previous studies on solar charger integrated system only focus on load charge control or switching Maximum Power Point Tracking (MPPT) and charge control modes. This study used two-stage system, which allows the overall portable solar energy charging system to implement MPPT and optimal charge control of Li-ion battery simultaneously. First, this study designs a DC/DC boost converter of solar power generation, which uses variable step size incremental conductance method (VSINC) to enable the solar cell to track the maximum power point at any time. The voltage was exported from the DC/DC boost converter to the DC/DC buck converter, so that the voltage dropped to proper voltage for charging the battery. The charging system uses constant current/constant voltage (CC/CV) method to charge the lithium battery. In order to obtain the optimum PI charge controller parameters, this study used intelligent algorithm to determine the optimum parameters. According to the simulation and experimental results, the control parameters resulted from PSO have better performance than genetic algorithms (GAs).

  1. An ultraviolet responsive hybrid solar cell based on titania/poly(3-hexylthiophene).

    PubMed

    Wu, Jihuai; Yue, Gentian; Xiao, Yaoming; Lin, Jianming; Huang, Miaoliang; Lan, Zhang; Tang, Qunwei; Huang, Yunfang; Fan, Leqing; Yin, Shu; Sato, Tsugio

    2013-01-01

    Here we present an ultraviolet responsive inorganic-organic hybrid solar cell based on titania/poly(3-hexylthiophene) (TiO(2)/P3HT) heterojuction. In this solar cell, TiO(2) is an ultraviolet light absorber and electronic conductor, P3HT is a hole conductor, the light-to-electrical conversion is realized by the cooperation for these two components. Doping ionic salt in P3HT polymer can improve the photovoltaic performance of the solar cell. Under ultraviolet light irradiation with intensity of 100 mW·cm(-2), the hybrid solar cell doped with 1.0 wt.% lithium iodide achieves an energy conversion efficiency of 1.28%, which is increased by 33.3% compared to that of the hybrid solar cell without lithium iodide doping. Our results open a novel sunlight irradiation field for solar energy utilization, demonstrate the feasibility of ultraviolet responsive solar cells, and provide a new route for enhancing the photovoltaic performance of solar cells.

  2. An ultraviolet responsive hybrid solar cell based on titania/poly(3-hexylthiophene)

    PubMed Central

    Wu, Jihuai; Yue, Gentian; Xiao, Yaoming; Lin, Jianming; Huang, Miaoliang; Lan, Zhang; Tang, Qunwei; Huang, Yunfang; Fan, Leqing; Yin, Shu; Sato, Tsugio

    2013-01-01

    Here we present an ultraviolet responsive inorganic-organic hybrid solar cell based on titania/poly(3-hexylthiophene) (TiO2/P3HT) heterojuction. In this solar cell, TiO2 is an ultraviolet light absorber and electronic conductor, P3HT is a hole conductor, the light-to-electrical conversion is realized by the cooperation for these two components. Doping ionic salt in P3HT polymer can improve the photovoltaic performance of the solar cell. Under ultraviolet light irradiation with intensity of 100 mW·cm−2, the hybrid solar cell doped with 1.0 wt.% lithium iodide achieves an energy conversion efficiency of 1.28%, which is increased by 33.3% compared to that of the hybrid solar cell without lithium iodide doping. Our results open a novel sunlight irradiation field for solar energy utilization, demonstrate the feasibility of ultraviolet responsive solar cells, and provide a new route for enhancing the photovoltaic performance of solar cells. PMID:23412470

  3. Atomic Structure of Interface States in Silicon Heterojunction Solar Cells

    NASA Astrophysics Data System (ADS)

    George, B. M.; Behrends, J.; Schnegg, A.; Schulze, T. F.; Fehr, M.; Korte, L.; Rech, B.; Lips, K.; Rohrmüller, M.; Rauls, E.; Schmidt, W. G.; Gerstmann, U.

    2013-03-01

    Combining orientation dependent electrically detected magnetic resonance and g tensor calculations based on density functional theory we assign microscopic structures to paramagnetic states involved in spin-dependent recombination at the interface of hydrogenated amorphous silicon crystalline silicon (a-Si:H/c-Si) heterojunction solar cells. We find that (i) the interface exhibits microscopic roughness, (ii) the electronic structure of the interface defects is mainly determined by c-Si, (iii) we identify the microscopic origin of the conduction band tail state in the a-Si:H layer, and (iv) present a detailed recombination mechanism.

  4. Predicting solar radiation based on available weather indicators

    NASA Astrophysics Data System (ADS)

    Sauer, Frank Joseph

    Solar radiation prediction models are complex and require software that is not available for the household investor. The processing power within a normal desktop or laptop computer is sufficient to calculate similar models. This barrier to entry for the average consumer can be fixed by a model simple enough to be calculated by hand if necessary. Solar radiation modeling has been historically difficult to predict and accurate models have significant assumptions and restrictions on their use. Previous methods have been limited to linear relationships, location restrictions, or input data limits to one atmospheric condition. This research takes a novel approach by combining two techniques within the computational limits of a household computer; Clustering and Hidden Markov Models (HMMs). Clustering helps limit the large observation space which restricts the use of HMMs. Instead of using continuous data, and requiring significantly increased computations, the cluster can be used as a qualitative descriptor of each observation. HMMs incorporate a level of uncertainty and take into account the indirect relationship between meteorological indicators and solar radiation. This reduces the complexity of the model enough to be simply understood and accessible to the average household investor. The solar radiation is considered to be an unobservable state that each household will be unable to measure. The high temperature and the sky coverage are already available through the local or preferred source of weather information. By using the next day's prediction for high temperature and sky coverage, the model groups the data and then predicts the most likely range of radiation. This model uses simple techniques and calculations to give a broad estimate for the solar radiation when no other universal model exists for the average household.

  5. Wavelet Based Characterization of Low Radio Frequency Solar Emissions

    NASA Astrophysics Data System (ADS)

    Suresh, A.; Sharma, R.; Das, S. B.; Oberoi, D.; Pankratius, V.; Lonsdale, C.

    2016-12-01

    Low-frequency solar radio observations with the Murchison Widefield Array (MWA) have revealed the presence of numerous short-lived, narrow-band weak radio features, even during quiet solar conditions. In their appearance in in the frequency-time plane, they come closest to the solar type III bursts, but with much shorter spectral spans and flux densities, so much so that they are not detectable with the usual swept frequency radio spectrographs. These features occur at rates of many thousand features per hour in the 30.72 MHz MWA bandwidth, and hence necessarily require an automated approach to determine robust statistical estimates of their properties, e.g., distributions of spectral widths, temporal spans, flux densities, slopes in the time-frequency plane and distribution over frequency. To achieve this, a wavelet decomposition approach has been developed for feature recognition and subsequent parameter extraction from the MWA dynamic spectrum. This work builds on earlier work by the members of this team to achieve a reliable flux calibration in a computationally efficient manner. Preliminary results show that the distribution of spectral span of these features peaks around 3 MHz, most of them last for less than two seconds and are characterized by flux densities of about 60% of the background solar emission. In analogy with the solar type III bursts, this non-thermal emission is envisaged to arise via coherent emission processes. There is also an exciting possibility that these features might correspond to radio signatures of nanoflares, hypothesized (Gold, 1964; Parker, 1972) to explain coronal heating.

  6. Molecular Monolayers for Electrical Passivation and Functionalization of Silicon-Based Solar Energy Devices.

    PubMed

    Veerbeek, Janneke; Firet, Nienke J; Vijselaar, Wouter; Elbersen, Rick; Gardeniers, Han; Huskens, Jurriaan

    2017-01-11

    Silicon-based solar fuel devices require passivation for optimal performance yet at the same time need functionalization with (photo)catalysts for efficient solar fuel production. Here, we use molecular monolayers to enable electrical passivation and simultaneous functionalization of silicon-based solar cells. Organic monolayers were coupled to silicon surfaces by hydrosilylation in order to avoid an insulating silicon oxide layer at the surface. Monolayers of 1-tetradecyne were shown to passivate silicon micropillar-based solar cells with radial junctions, by which the efficiency increased from 8.7% to 9.9% for n + /p junctions and from 7.8% to 8.8% for p + /n junctions. This electrical passivation of the surface, most likely by removal of dangling bonds, is reflected in a higher shunt resistance in the J-V measurements. Monolayers of 1,8-nonadiyne were still reactive for click chemistry with a model catalyst, thus enabling simultaneous passivation and future catalyst coupling.

  7. 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.

  8. 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

  9. The status of lightweight photovoltaic space array technology based on amorphous silicon solar cells

    NASA Technical Reports Server (NTRS)

    Hanak, Joseph J.; Kaschmitter, Jim

    1991-01-01

    Ultralight, flexible photovoltaic (PV) array of amorphous silicon (a-Si) was identified as a potential low cost power source for small satellites. A survey was conducted of the status of the a-Si PV array technology with respect to present and future performance, availability, cost, and risks. For existing, experimental array blankets made of commercial cell material, utilizing metal foil substrates, the Beginning of Life (BOL) performance at Air Mass Zero (AM0) and 35 C includes total power up to 200 W, power per area of 64 W/sq m and power per weight of 258 W/kg. Doubling of power per weight occurs when polyimide substrates are used. Estimated End of Life (EOL) power output after 10 years in a nominal low earth orbit would be 80 pct. of BOL, the degradation being due to largely light induced effects (-10 to -15 pct.) and in part (-5 pct.) to space radiation. Predictions for the year 1995 for flexible PV arrays, made on the basis of published results for rigid a-Si modules, indicate EOL power output per area and per weight of 105 W/sq m and 400 W/kg, respectively, while predictions for the late 1990s based on existing U.S. national PV program goals indicate EOL values of 157 W/sq m and 600 W/kg. Cost estimates by vendors for 200 W ultralight arrays in volume of over 1000 units range from $100/watt to $125/watt. Identified risks include the lack of flexible, space compatible encapsulant, the lack of space qualification effort, recent partial or full acquisitions of US manufacturers of a-Si cells by foreign firms, and the absence of a national commitment for a long range development program toward developing of this important power source for space.

  10. PICARD SOL mission, a ground-based facility for long-term solar radius measurement

    NASA Astrophysics Data System (ADS)

    Meftah, M.; Irbah, A.; Corbard, T.; Morand, F.; Thuillier, G.; Hauchecorne, A.; Ikhlef, R.; Rouze, M.; Renaud, C.; Djafer, D.; Abbaki, S.; Assus, P.; Chauvineau, B.; Cissé, E. M.; Dalaudier, F.; D'Almeida, Eric; Fodil, M.; Laclare, F.; Lesueur, P.; Lin, M.; Marcovici, J. P.; Poiet, G.

    2012-09-01

    For the last thirty years, ground time series of the solar radius have shown different variations according to different instruments. The origin of these variations may be found in the observer, the instrument, the atmosphere and the Sun. These time series show inconsistencies and conflicting results, which likely originate from instrumental effects and/or atmospheric effects. A survey of the solar radius was initiated in 1975 by F. Laclare, at the Calern site of the Observatoire de la Cˆote d'Azur (OCA). PICARD is an investigation dedicated to the simultaneous measurements of the absolute total and spectral solar irradiance, the solar radius and solar shape, and to the Sun's interior probing by the helioseismology method. The PICARD mission aims to the study of the origin of the solar variability and to the study of the relations between the Sun and the Earth's climate by using modeling. These studies will be based on measurements carried out from orbit and from the ground. PICARD SOL is the ground segment of the PICARD mission to allow a comparison of the solar radius measured in space and on ground. PICARD SOL will enable to understand the influence of the atmosphere on the measured solar radius. The PICARD Sol instrumentation consists of: SODISM II, a replica of SODISM (SOlar Diameter Imager and Surface Mapper), a high resolution imaging telescope, and MISOLFA (Moniteur d'Images SOLaires Franco-Alǵerien), a seeing monitor. Additional instrumentation consists in a Sun photometer, which measures atmospheric aerosol properties, a pyranometer to measure the solar irradiance, a visible camera, and a weather station. PICARD SOL is operating since March 2011. First results from the PICARD SOL mission are briefly reported in this paper.

  11. Advances in graphene-based semiconductor photocatalysts for solar energy conversion: fundamentals and materials engineering.

    PubMed

    Xie, Xiuqiang; Kretschmer, Katja; Wang, Guoxiu

    2015-08-28

    Graphene-based semiconductor photocatalysis has been regarded as a promising technology for solar energy storage and conversion. In this review, we summarized recent developments of graphene-based photocatalysts, including preparation of graphene-based photocatalysts, typical key advances in the understanding of graphene functions for photocatalytic activity enhancement and methodologies to regulate the electron transfer efficiency in graphene-based composite photocatalysts, by which we hope to offer enriched information to harvest the utmost fascinating properties of graphene as a platform to construct efficient graphene-based composite photocatalysts for solar-to-energy conversion.

  12. A solar rechargeable flow battery based on photoregeneration of two soluble redox couples.

    PubMed

    Liu, Ping; Cao, Yu-liang; Li, Guo-Ran; Gao, Xue-Ping; Ai, Xin-Ping; Yang, Han-Xi

    2013-05-01

    Storable sunshine, reusable rays: A solar rechargeable redox flow battery is proposed based on the photoregeneration of I(3)(-)/I(-) and [Fe(C(10)H(15))(2)](+)/Fe(C(10)H(15))(2) soluble redox couples, which can be regenerated by flowing from a discharged redox flow battery (RFB) into a dye-sensitized solar cell (DSSC) and then stored in tanks for subsequent RFB applications This technology enables effective solar-to-chemical energy conversion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Enhanced performance of a structured cyclo olefin copolymer-based amorphous silicon solar cell

    NASA Astrophysics Data System (ADS)

    Zhan, Xinghua; Chen, Fei; Gao, Mengyu; Tie, Shengnian; Gao, Wei

    2017-07-01

    The submicron array was fabricated onto a cyclo olefin copolymer (COC) film by a hot embossing method. An amorphous silicon p-i-n junction and transparent conductive layers were then deposited onto it through a plasma enhanced chemical vapor deposition (PECVD) and magnetron sputtering. The efficiency of the fabricated COC-based solar cell was measured and the result demonstrated 18.6% increase of the solar cell efficiency when compared to the sample without array structure. The imprinted polymer solar cells with submicron array indeed increase their efficiency.

  14. Solar Astronomy Data Base: Packaged Information on Diskette

    NASA Technical Reports Server (NTRS)

    Mckinnon, John A.

    1990-01-01

    In its role as a library, the National Geophysical Data Center has transferred to diskette a collection of small, digital files of routinely measured solar indices for use on an IBM-compatible desktop computer. Recording these observations on diskette allows the distribution of specialized information to researchers with a wide range of expertise in computer science and solar astronomy. Every data set was made self-contained by including formats, extraction utilities, and plain-language descriptive text. Moreover, for several archives, two versions of the observations are provided - one suitable for display, the other for analysis with popular software packages. Since the files contain no control characters, each one can be modified with any text editor.

  15. Design of Solar Street Lamp Control System Based on MPPT

    NASA Astrophysics Data System (ADS)

    Cui, Fengying

    This paper proposes a new solar street lamp control system which is composed of photovoltaic cell, controller, battery and load. In this system controller as the key part applies the microchip to achieve many functions. According to the nonlinear output characteristics of solar cell and the influence of environment, it uses the perturbation and observation (P&O) method to realize the maximum power point tracking (MPPT) and promotes the efficiency. In order to prolong the battery life the pulse width modulation (PWM) charge mode is selected to control the battery capacity and provent the battery from the state of over-charge and over-discharge. Meanwhile the function of temperature compensation, charge and discharge protection are set to improve the running safety and stability.

  16. A Solar Time-Based Analog Ensemble Method for Regional Solar Power Forecasting

    SciTech Connect

    Hodge, Brian S; Zhang, Xinmin; Li, Yuan

    This paper presents a new analog ensemble method for day-ahead regional photovoltaic (PV) power forecasting with hourly resolution. By utilizing open weather forecast and power measurement data, this prediction method is processed within a set of historical data with similar meteorological data (temperature and irradiance), and astronomical date (solar time and earth declination angle). Further, clustering and blending strategies are applied to improve its accuracy in regional PV forecasting. The robustness of the proposed method is demonstrated with three different numerical weather prediction models, the North American Mesoscale Forecast System, the Global Forecast System, and the Short-Range Ensemble Forecast, formore » both region level and single site level PV forecasts. Using real measured data, the new forecasting approach is applied to the load zone in Southeastern Massachusetts as a case study. The normalized root mean square error (NRMSE) has been reduced by 13.80%-61.21% when compared with three tested baselines.« less

  17. Heliosynthesis: A solar biotechnology based on direct bioconversion of solar energy by photosynthetic cells

    NASA Astrophysics Data System (ADS)

    Gudin, C.

    1982-12-01

    Certain limiting aspects of current technology should be studied, such as the lifetimes of tubing material and the utilization of renewable sources of energy for pumping. Only exocellular or cellular biomass with high specific value, involving small markets and small plant areas (less than 1 ha), will be economically possible for the short term and will allow improvement of this technology. A valorization of the totality of photosynthetic biomass with respect to economics and energy is an absolute necessity. There is an immediate need for genetic studies of microalgae that will allow enhancement or even creation of chemical production satisfying economic and energy needs. Such efforts should permit the rapid establishment of an aggressive and sophisticated solar biotechnology that integrates scientific and technical' developments to meet the new needs of humanity for food, chemicals, and energy, thereby complementing agriculture with a sort of cellular horticulture.

  18. Combined Radio and Space-Based Solar Observations: From Techniques to New Results - Preface

    NASA Astrophysics Data System (ADS)

    Kontar, Eduard P.; Nindos, Alexander

    2018-06-01

    The phenomena observed at the Sun have a variety of unique radio signatures that can be used to diagnose the processes in the solar atmosphere. The insights provided by radio observations are further enhanced when they are combined with observations from space-based telescopes. This Topical collection demonstrates the power of combination methodology at work and provides new results on i) type I solar radio bursts and thermal emission to study active regions; ii) type II and IV bursts to better understand the structure of coronal mass ejections; and iii) non-thermal gyro-synchrotron and/or type III bursts to improve the characterisation of particle acceleration in solar flares. The ongoing improvements in time, frequency, and spatial resolutions of ground-based telescopes reveal new levels in the complexity of solar phenomena and pose new questions.

  19. Considerably improved photovoltaic performance of carbon nanotube-based solar cells using metal oxide layers.

    PubMed

    Wang, Feijiu; Kozawa, Daichi; Miyauchi, Yuhei; Hiraoka, Kazushi; Mouri, Shinichiro; Ohno, Yutaka; Matsuda, Kazunari

    2015-02-18

    Carbon nanotube-based solar cells have been extensively studied from the perspective of potential application. Here we demonstrated a significant improvement of the carbon nanotube solar cells by the use of metal oxide layers for efficient carrier transport. The metal oxides also serve as an antireflection layer and an efficient carrier dopant, leading to a reduction in the loss of the incident solar light and an increase in the photocurrent, respectively. As a consequence, the photovoltaic performance of both p-single-walled carbon nanotube (SWNT)/n-Si and n-SWNT/p-Si heterojunction solar cells using MoOx and ZnO layers is improved, resulting in very high photovoltaic conversion efficiencies of 17.0 and 4.0%, respectively. These findings regarding the use of metal oxides as multifunctional layers suggest that metal oxide layers could improve the performance of various electronic devices based on carbon nanotubes.

  20. Considerably improved photovoltaic performance of carbon nanotube-based solar cells using metal oxide layers

    NASA Astrophysics Data System (ADS)

    Wang, Feijiu; Kozawa, Daichi; Miyauchi, Yuhei; Hiraoka, Kazushi; Mouri, Shinichiro; Ohno, Yutaka; Matsuda, Kazunari

    2015-02-01

    Carbon nanotube-based solar cells have been extensively studied from the perspective of potential application. Here we demonstrated a significant improvement of the carbon nanotube solar cells by the use of metal oxide layers for efficient carrier transport. The metal oxides also serve as an antireflection layer and an efficient carrier dopant, leading to a reduction in the loss of the incident solar light and an increase in the photocurrent, respectively. As a consequence, the photovoltaic performance of both p-single-walled carbon nanotube (SWNT)/n-Si and n-SWNT/p-Si heterojunction solar cells using MoOx and ZnO layers is improved, resulting in very high photovoltaic conversion efficiencies of 17.0 and 4.0%, respectively. These findings regarding the use of metal oxides as multifunctional layers suggest that metal oxide layers could improve the performance of various electronic devices based on carbon nanotubes.

  1. Metastability of a-SiOx:H thin films for c-Si surface passivation

    NASA Astrophysics Data System (ADS)

    Serenelli, L.; Martini, L.; Imbimbo, L.; Asquini, R.; Menchini, F.; Izzi, M.; Tucci, M.

    2017-01-01

    The adoption of a-SiOx:H films obtained by PECVD in heterojunction solar cells is a key to further increase their efficiency, because of its transparency in the UV with respect to the commonly used a-Si:H. At the same time this layer must guarantee high surface passivation of the c-Si to be suitable in high efficiency solar cell manufacturing. On the other hand the application of amorphous materials like a-Si:H and SiNx on the cell frontside expose them to the mostly energetic part of the sun spectrum, leading to a metastability of their passivation properties. Moreover as for amorphous silicon, thermal annealing procedures are considered as valuable steps to enhance and stabilize thin film properties, when performed at opportune temperature. In this work we explored the reliability of a-SiOx:H thin film layers surface passivation on c-Si substrates under UV exposition, in combination with thermal annealing steps. Both p- and n-type doped c-Si substrates were considered. To understand the effect of UV light soaking we monitored the minority carriers lifetime and Sisbnd H and Sisbnd O bonding, by FTIR spectra, after different exposure times to light coming from a deuterium lamp, filtered to UV-A region, and focused on the sample to obtain a power density of 50 μW/cm2. We found a certain lifetime decrease after UV light soaking in both p- and n-type c-Si passivated wafers according to a a-SiOx:H/c-Si/a-SiOx:H structure. The role of a thermal annealing, which usually enhances the as-deposited SiOx passivation properties, was furthermore considered. In particular we monitored the UV light soaking effect on c-Si wafers after a-SiOx:H coating by PECVD and after a thermal annealing treatment at 300 °C for 30 min, having selected these conditions on the basis of the study of the effect due to different temperatures and durations. We correlated the lifetime evolution and the metastability effect of thermal annealing to the a-SiOx:H/c-Si interface considering the evolution

  2. Solar-thermal conversion and thermal energy storage of graphene foam-based composites.

    PubMed

    Zhang, Lianbin; Li, Renyuan; Tang, Bo; Wang, Peng

    2016-08-14

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances the heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.

  3. Performance Evaluation of a Nanofluid-Based Direct Absorption Solar Collector with Parabolic Trough Concentrator

    PubMed Central

    Xu, Guoying; Chen, Wei; Deng, Shiming; Zhang, Xiaosong; Zhao, Sainan

    2015-01-01

    Application of solar collectors for hot water supply, space heating, and cooling plays a significant role in reducing building energy consumption. For conventional solar collectors, solar radiation is absorbed by spectral selective coating on the collectors’ tube/plate wall. The poor durability of the coating can lead to an increased manufacturing cost and unreliability for a solar collector operated at a higher temperature. Therefore, a novel nanofluid-based direct absorption solar collector (NDASC) employing uncoated collector tubes has been proposed, and its operating characteristics for medium-temperature solar collection were theoretically and experimentally studied in this paper. CuO/oil nanofluid was prepared and used as working fluid of the NDASC. The heat-transfer mechanism of the NDASC with parabolic trough concentrator was theoretically evaluated and compared with a conventional indirect absorption solar collector (IASC). The theoretical analysis results suggested that the fluid’s temperature distribution in the NDASC was much more uniform than that in the IASC, and an enhanced collection efficiency could be achieved for the NDASC operated within a preferred working temperature range. To demonstrate the feasibility of the proposed NDASC, experimental performances of an NDASC and an IASC with the same parabolic trough concentrator were furthermore evaluated and comparatively discussed. PMID:28347112

  4. Performance Evaluation of a Nanofluid-Based Direct Absorption Solar Collector with Parabolic Trough Concentrator.

    PubMed

    Xu, Guoying; Chen, Wei; Deng, Shiming; Zhang, Xiaosong; Zhao, Sainan

    2015-12-04

    Application of solar collectors for hot water supply, space heating, and cooling plays a significant role in reducing building energy consumption. For conventional solar collectors, solar radiation is absorbed by spectral selective coating on the collectors' tube/plate wall. The poor durability of the coating can lead to an increased manufacturing cost and unreliability for a solar collector operated at a higher temperature. Therefore, a novel nanofluid-based direct absorption solar collector (NDASC) employing uncoated collector tubes has been proposed, and its operating characteristics for medium-temperature solar collection were theoretically and experimentally studied in this paper. CuO/oil nanofluid was prepared and used as working fluid of the NDASC. The heat-transfer mechanism of the NDASC with parabolic trough concentrator was theoretically evaluated and compared with a conventional indirect absorption solar collector (IASC). The theoretical analysis results suggested that the fluid's temperature distribution in the NDASC was much more uniform than that in the IASC, and an enhanced collection efficiency could be achieved for the NDASC operated within a preferred working temperature range. To demonstrate the feasibility of the proposed NDASC, experimental performances of an NDASC and an IASC with the same parabolic trough concentrator were furthermore evaluated and comparatively discussed.

  5. Progress in Tandem Solar Cells Based on Hybrid Organic-Inorganic Perovskites

    SciTech Connect

    Chen, Bo; Zheng, Xiaopeng; Bai, Yang

    Owing to their high efficiency, low-cost solution-processability, and tunable bandgap, perovskite solar cells (PSCs) made of hybrid organic-inorganic perovskite (HOIP) thin films are promising top-cell candidates for integration with bottom-cells based on Si or other low-bandgap solar-cell materials to boost the power conversion efficiency (PCE) beyond the Shockley-Quiesser (S-Q) limit. In this review, recent progress in such tandem solar cells based on the emerging PSCs is summarized and reviewed critically. Notable achievements for different tandem solar cell configurations including mechanically-stacked, optical coupling, and monolithically-integrated with PSCs as top-cells are described in detail. Highly-efficient semitransparent PSC top-cells with high transmittance inmore » near-infrared (NIR) region are critical for tandem solar cells. Different types of transparent electrodes with high transmittance and low sheet-resistance for PSCs are reviewed, which presents a grand challenge for PSCs. The strategies to obtain wide-bandgap PSCs with good photo-stability are discussed. In conclusion, the PCE reduction due to reflection loss, parasitic absorption, electrical loss, and current mismatch are analyzed to provide better understanding of the performance of PSC-based tandem solar cells.« less

  6. Progress in Tandem Solar Cells Based on Hybrid Organic-Inorganic Perovskites

    DOE PAGES

    Chen, Bo; Zheng, Xiaopeng; Bai, Yang; ...

    2017-03-06

    Owing to their high efficiency, low-cost solution-processability, and tunable bandgap, perovskite solar cells (PSCs) made of hybrid organic-inorganic perovskite (HOIP) thin films are promising top-cell candidates for integration with bottom-cells based on Si or other low-bandgap solar-cell materials to boost the power conversion efficiency (PCE) beyond the Shockley-Quiesser (S-Q) limit. In this review, recent progress in such tandem solar cells based on the emerging PSCs is summarized and reviewed critically. Notable achievements for different tandem solar cell configurations including mechanically-stacked, optical coupling, and monolithically-integrated with PSCs as top-cells are described in detail. Highly-efficient semitransparent PSC top-cells with high transmittance inmore » near-infrared (NIR) region are critical for tandem solar cells. Different types of transparent electrodes with high transmittance and low sheet-resistance for PSCs are reviewed, which presents a grand challenge for PSCs. The strategies to obtain wide-bandgap PSCs with good photo-stability are discussed. In conclusion, the PCE reduction due to reflection loss, parasitic absorption, electrical loss, and current mismatch are analyzed to provide better understanding of the performance of PSC-based tandem solar cells.« less

  7. Limitation of Ground-based Estimates of Solar Irradiance Due to Atmospheric Variations

    NASA Technical Reports Server (NTRS)

    Wen, Guoyong; Cahalan, Robert F.; Holben, Brent N.

    2003-01-01

    The uncertainty in ground-based estimates of solar irradiance is quantitatively related to the temporal variability of the atmosphere's optical thickness. The upper and lower bounds of the accuracy of estimates using the Langley Plot technique are proportional to the standard deviation of aerosol optical thickness (approx. +/- 13 sigma(delta tau)). The estimates of spectral solar irradiance (SSI) in two Cimel sun photometer channels from the Mauna Loa site of AERONET are compared with satellite observations from SOLSTICE (Solar Stellar Irradiance Comparison Experiment) on UARS (Upper Atmospheric Research Satellite) for almost two years of data. The true solar variations related to the 27-day solar rotation cycle observed from SOLSTICE are about 0.15% at the two sun photometer channels. The variability in ground-based estimates is statistically one order of magnitude larger. Even though about 30% of these estimates from all Level 2.0 Cimel data fall within the 0.4 to approx. 0.5% variation level, ground-based estimates are not able to capture the 27-day solar variation observed from SOLSTICE.

  8. A power pack based on organometallic perovskite solar cell and supercapacitor.

    PubMed

    Xu, Xiaobao; Li, Shaohui; Zhang, Hua; Shen, Yan; Zakeeruddin, Shaik M; Graetzel, Michael; Cheng, Yi-Bing; Wang, Mingkui

    2015-02-24

    We present an investigation on a power pack combining a CH3NH3PbI3-based solar cell with a polypyrrole-based supercapacitor and evaluate its performance as an energy pack. The package achieved an energy storage efficiency of 10%, which is much higher than that of other systems combining a PV cell with a supercapacitor. We find a high output voltage of 1.45 V for the device under AM 1.5G illumination when the CH3NH3PbI3-based solar cell is connected in series with a polypyrrole-based supercapacitor. This system affords continuous output of electric power by using CH3NH3PbI3-based solar cell as an energy source mitigating transients caused by light intensity fluctuations or the diurnal cycle.

  9. Harnessing Sun’s Energy with Quantum Dots Based Next Generation Solar Cell

    PubMed Central

    Halim, Mohammad A.

    2012-01-01

    Our energy consumption relies heavily on the three components of fossil fuels (oil, natural gas and coal) and nearly 83% of our current energy is consumed from those sources. The use of fossil fuels, however, has been viewed as a major environmental threat because of their substantial contribution to greenhouse gases which are responsible for increasing the global average temperature. Last four decades, scientists have been searching for alternative sources of energy which need to be environmentally clean, efficient, cost-effective, renewable, and sustainable. One of the promising sustainable sources of energy can be achieved by harnessing sun energy through silicon wafer, organic polymer, inorganic dye, and quantum dots based solar cells. Among them, quantum dots have an exceptional property in that they can excite multiple electrons using only one photon. These dots can easily be synthesized, processed in solution, and incorporated into solar cell application. Interestingly, the quantum dots solar cells can exceed the Shockley-Queisser limit; however, it is a great challenge for other solar cell materials to exceed the limit. Theoretically, the quantum dots solar cell can boost the power conversion efficiency up to 66% and even higher to 80%. Moreover, in changing the size of the quantum dots one can utilize the Sun’s broad spectrum of visible and infrared ranges. This review briefly overviews the present performance of different materials-based solar cells including silicon wafer, dye-sensitized, and organic solar cells. In addition, recent advances of the quantum dots based solar cells which utilize cadmium sulfide/selenide, lead sulfide/selenide, and new carbon dots as light harvesting materials has been reviewed. A future outlook is sketched as to how one could improve the efficiency up to 10% from the current highest efficiency of 6.6%. PMID:28348320

  10. Harnessing Sun's Energy with Quantum Dots Based Next Generation Solar Cell.

    PubMed

    Halim, Mohammad A

    2012-12-27

    Our energy consumption relies heavily on the three components of fossil fuels (oil, natural gas and coal) and nearly 83% of our current energy is consumed from those sources. The use of fossil fuels, however, has been viewed as a major environmental threat because of their substantial contribution to greenhouse gases which are responsible for increasing the global average temperature. Last four decades, scientists have been searching for alternative sources of energy which need to be environmentally clean, efficient, cost-effective, renewable, and sustainable. One of the promising sustainable sources of energy can be achieved by harnessing sun energy through silicon wafer, organic polymer, inorganic dye, and quantum dots based solar cells. Among them, quantum dots have an exceptional property in that they can excite multiple electrons using only one photon. These dots can easily be synthesized, processed in solution, and incorporated into solar cell application. Interestingly, the quantum dots solar cells can exceed the Shockley - Queisser limit; however, it is a great challenge for other solar cell materials to exceed the limit. Theoretically, the quantum dots solar cell can boost the power conversion efficiency up to 66% and even higher to 80%. Moreover, in changing the size of the quantum dots one can utilize the Sun's broad spectrum of visible and infrared ranges. This review briefly overviews the present performance of different materials-based solar cells including silicon wafer, dye-sensitized, and organic solar cells. In addition, recent advances of the quantum dots based solar cells which utilize cadmium sulfide/selenide, lead sulfide/selenide, and new carbon dots as light harvesting materials has been reviewed. A future outlook is sketched as to how one could improve the efficiency up to 10% from the current highest efficiency of 6.6%.

  11. Polar low ionospheric responses to the most energetic SPE of the solar cycle#23 based on cosmic noise absorption

    NASA Astrophysics Data System (ADS)

    Pacini, A. A.; Garnett Marques Brum, C.

    2013-12-01

    We present a detailed study of the impact of solar proton event over the polar low ionosphere, occurred Jan/2005, during the descendent phase of the last solar activity cycle XXIII. This event was the hardest SPE of the last solar cycle, and was associated to a solar X-ray flare X.2 and CME halo. For this study, we are using cosmic noise absorption data measured by a riometer located in Oulu, Finland (65N) along with solar proton data from GOES satellite. Based on computation simulations we intend to explain the 30MHz riometer absorption events based on variations of the flux and spectrum of the energetic particle precipitated.

  12. Developing a new solar radiation estimation model based on Buckingham theorem

    NASA Astrophysics Data System (ADS)

    Ekici, Can; Teke, Ismail

    2018-06-01

    While the value of solar radiation can be expressed physically in the days without clouds, this expression becomes difficult in cloudy and complicated weather conditions. In addition, solar radiation measurements are often not taken in developing countries. In such cases, solar radiation estimation models are used. Solar radiation prediction models estimate solar radiation using other measured meteorological parameters those are available in the stations. In this study, a solar radiation estimation model was obtained using Buckingham theorem. This theory has been shown to be useful in predicting solar radiation. In this study, Buckingham theorem is used to express the solar radiation by derivation of dimensionless pi parameters. This derived model is compared with temperature based models in the literature. MPE, RMSE, MBE and NSE error analysis methods are used in this comparison. Allen, Hargreaves, Chen and Bristow-Campbell models in the literature are used for comparison. North Dakota's meteorological data were used to compare the models. Error analysis were applied through the comparisons between the models in the literature and the model that is derived in the study. These comparisons were made using data obtained from North Dakota's agricultural climate network. In these applications, the model obtained within the scope of the study gives better results. Especially, in terms of short-term performance, it has been found that the obtained model gives satisfactory results. It has been seen that this model gives better accuracy in comparison with other models. It is possible in RMSE analysis results. Buckingham theorem was found useful in estimating solar radiation. In terms of long term performances and percentage errors, the model has given good results.

  13. Organic Solar Cells Based on Electrodeposited Polyaniline Films

    NASA Astrophysics Data System (ADS)

    Inoue, Kei; Akiyama, Tsuyoshi; Suzuki, Atsushi; Oku, Takeo

    2012-04-01

    Polyaniline thin films as hole transporting layers were fabricated on transparent indium-tin-oxide electrodes by electrodeposition of aniline in an aqueous H2SO4 electrolyte solution. Emerald-green polyaniline films were obtained, which showed stable redox waves. A mixed solution of polythiophene and fullerene derivative was spin-coated onto the electrodeposited polyaniline film. After the modification of titanium oxide film on the surface of the polythiophene/fullerene layer, an aluminum electrode was fabricated by vacuum deposition. The obtained solar cells generated stable photocurrent and photovoltage under light illumination.

  14. Evaluation of the National Solar Radiation Database (NSRDB) Using Ground-Based Measurements

    NASA Astrophysics Data System (ADS)

    Xie, Y.; Sengupta, M.; Habte, A.; Lopez, A.

    2017-12-01

    Solar resource is essential for a wide spectrum of applications including renewable energy, climate studies, and solar forecasting. Solar resource information can be obtained from ground-based measurement stations and/or from modeled data sets. While measurements provide data for the development and validation of solar resource models and other applications modeled data expands the ability to address the needs for increased accuracy and spatial and temporal resolution. The National Renewable Energy Laboratory (NREL) has developed and regular updates modeled solar resource through the National Solar Radiation Database (NSRDB). The recent NSRDB dataset was developed using the physics-based Physical Solar Model (PSM) and provides gridded solar irradiance (global horizontal irradiance (GHI), direct normal irradiance (DNI), and diffuse horizontal irradiance) at a 4-km by 4-km spatial and half-hourly temporal resolution covering 18 years from 1998-2015. A comprehensive validation of the performance of the NSRDB (1998-2015) was conducted to quantify the accuracy of the spatial and temporal variability of the solar radiation data. Further, the study assessed the ability of NSRDB (1998-2015) to accurately capture inter-annual variability, which is essential information for solar energy conversion projects and grid integration studies. Comparisons of the NSRDB (1998-2015) with nine selected ground-measured data were conducted under both clear- and cloudy-sky conditions. These locations provide a high quality data covering a variety of geographical locations and climates. The comparison of the NSRDB to the ground-based data demonstrated that biases were within +/- 5% for GHI and +/-10% for DNI. A comprehensive uncertainty estimation methodology was established to analyze the performance of the gridded NSRDB and includes all sources of uncertainty at various time-averaged periods, a method that is not often used in model evaluation. Further, the study analyzed the inter

  15. Effects of the c-Si/a-SiO2 interfacial atomic structure on its band alignment: an ab initio study.

    PubMed

    Zheng, Fan; Pham, Hieu H; Wang, Lin-Wang

    2017-12-13

    The crystalline-Si/amorphous-SiO 2 (c-Si/a-SiO 2 ) interface is an important system used in many applications, ranging from transistors to solar cells. The transition region of the c-Si/a-SiO 2 interface plays a critical role in determining the band alignment between the two regions. However, the question of how this interface band offset is affected by the transition region thickness and its local atomic arrangement is yet to be fully investigated. Here, by controlling the parameters of the classical Monte Carlo bond switching algorithm, we have generated the atomic structures of the interfaces with various thicknesses, as well as containing Si at different oxidation states. A hybrid functional method, as shown by our calculations to reproduce the GW and experimental results for bulk Si and SiO 2 , was used to calculate the electronic structure of the heterojunction. This allowed us to study the correlation between the interface band characterization and its atomic structures. We found that although the systems with different thicknesses showed quite different atomic structures near the transition region, the calculated band offset tended to be the same, unaffected by the details of the interfacial structure. Our band offset calculation agrees well with the experimental measurements. This robustness of the interfacial electronic structure to its interfacial atomic details could be another reason for the success of the c-Si/a-SiO 2 interface in Si-based electronic applications. Nevertheless, when a reactive force field is used to generate the a-SiO 2 and c-Si/a-SiO 2 interfaces, the band offset significantly deviates from the experimental values by about 1 eV.

  16. Effects of the c-Si/a-SiO 2 interfacial atomic structure on its band alignment: an ab initio study

    SciTech Connect

    Zheng, Fan; Pham, Hieu H.; Wang, Lin-Wang

    The crystalline-Si/amorphous-SiO 2 (c-Si/a-SiO 2) interface is an important system used in many applications, ranging from transistors to solar cells. The transition region of the c-Si/a-SiO 2 interface plays a critical role in determining the band alignment between the two regions. However, the question of how this interface band offset is affected by the transition region thickness and its local atomic arrangement is yet to be fully investigated. Here in this study, by controlling the parameters of the classical Monte Carlo bond switching algorithm, we have generated the atomic structures of the interfaces with various thicknesses, as well as containingmore » Si at different oxidation states. A hybrid functional method, as shown by our calculations to reproduce the GW and experimental results for bulk Si and SiO 2, was used to calculate the electronic structure of the heterojunction. This allowed us to study the correlation between the interface band characterization and its atomic structures. We found that although the systems with different thicknesses showed quite different atomic structures near the transition region, the calculated band offset tended to be the same, unaffected by the details of the interfacial structure. Our band offset calculation agrees well with the experimental measurements. This robustness of the interfacial electronic structure to its interfacial atomic details could be another reason for the success of the c-Si/a-SiO 2 interface in Si-based electronic applications. Nevertheless, when a reactive force field is used to generate the a-SiO 2 and c-Si/a-SiO 2 interfaces, the band offset significantly deviates from the experimental values by about 1 eV« less

  17. Effects of the c-Si/a-SiO 2 interfacial atomic structure on its band alignment: an ab initio study

    DOE PAGES

    Zheng, Fan; Pham, Hieu H.; Wang, Lin-Wang

    2017-11-13

    The crystalline-Si/amorphous-SiO 2 (c-Si/a-SiO 2) interface is an important system used in many applications, ranging from transistors to solar cells. The transition region of the c-Si/a-SiO 2 interface plays a critical role in determining the band alignment between the two regions. However, the question of how this interface band offset is affected by the transition region thickness and its local atomic arrangement is yet to be fully investigated. Here in this study, by controlling the parameters of the classical Monte Carlo bond switching algorithm, we have generated the atomic structures of the interfaces with various thicknesses, as well as containingmore » Si at different oxidation states. A hybrid functional method, as shown by our calculations to reproduce the GW and experimental results for bulk Si and SiO 2, was used to calculate the electronic structure of the heterojunction. This allowed us to study the correlation between the interface band characterization and its atomic structures. We found that although the systems with different thicknesses showed quite different atomic structures near the transition region, the calculated band offset tended to be the same, unaffected by the details of the interfacial structure. Our band offset calculation agrees well with the experimental measurements. This robustness of the interfacial electronic structure to its interfacial atomic details could be another reason for the success of the c-Si/a-SiO 2 interface in Si-based electronic applications. Nevertheless, when a reactive force field is used to generate the a-SiO 2 and c-Si/a-SiO 2 interfaces, the band offset significantly deviates from the experimental values by about 1 eV« less

  18. A comprehensive solar energy system analysis data base in Huntsville, Alabama

    NASA Technical Reports Server (NTRS)

    Goddard, J. P.

    1978-01-01

    The history of a comprehensive solar energy system analysis data base developed by NASA/Marshall Space Flight Center and the University of Alabama is presented, along with its current status. The Marshall Information Retrieval and Data Storage (MIRADS) system was chosen for the data base, and feedback systems were arranged to cope with changes in the needs of the program management for the type of data gathered. The final structure of the data base consists of 22 files divided into 6 topical sections: summaries, climatological, utility rates, architectural, equipment, and economics. The data base offers help to the solar industry in two ways: it provides information and it serves as a model for users trying to establish the climatic and socioeconomic variables they should take into account when they examine a potential market for solar energy equipment.

  19. GaAsPN-based PIN solar cells MBE-grown on GaP substrates: toward the III-V/Si tandem solar cell

    NASA Astrophysics Data System (ADS)

    Da Silva, M.; Almosni, S.; Cornet, C.; Létoublon, A.; Levallois, C.; Rale, P.; Lombez, L.; Guillemoles, J.-F.; Durand, O.

    2015-03-01

    GaAsPN semiconductors are promising material for the elaboration of high efficiencies tandem solar cells on silicon substrates. GaAsPN diluted nitride alloy is studied as the top junction material due to its perfect lattice matching with the Si substrate and its ideal bandgap energy allowing a perfect current matching with the Si bottom cell. We review our recent progress in materials development of the GaAsPN alloy and our recent studies of some of the different building blocks toward the elaboration of a PIN solar cell. A lattice matched (with a GaP(001) substrate, as a first step toward the elaboration on a Si substrate) 1μm-thick GaAsPN alloy has been grown by MBE. After a post-growth annealing step, this alloy displays a strong absorption around 1.8-1.9 eV, and efficient photoluminescence at room temperature suitable for the elaboration of the targeted solar cell top junction. Early stage GaAsPN PIN solar cells prototypes have been grown on GaP (001) substrates, with 2 different absorber thicknesses (1μm and 0.3μm). The external quantum efficiencies and the I-V curves show that carriers have been extracted from the GaAsPN alloy absorbers, with an open-circuit voltage of 1.18 V, while displaying low short circuit currents meaning that the GaAsPN structural properties needs a further optimization. A better carrier extraction has been observed with the absorber displaying the smallest thickness, which is coherent with a low carriers diffusion length in our GaAsPN compound. Considering all the pathways for improvement, the efficiency obtained under AM1.5G is however promising.

  20. RECOMBINATION PROCESSES AND NATURE OF THE TAIL AND GAP STATES IN a-Si:H and a-Si:H/a-SiNx:H MULTILAYERS

    NASA Astrophysics Data System (ADS)

    Morigaki, K.

    We discuss recombination processes and nature of the tail and gap states in a-Si:H and a-Si:H/a-SiNx:H multilayers on the basis of our ODMR, luminescence, photoinduced absorption and ENDOR measurements. We present other results relevant to this subject and attempt to interpret them in terms of our model.

  1. Chlorophyll-Based Organic-Inorganic Heterojunction Solar Cells.

    PubMed

    Li, Yue; Zhao, Wenjie; Li, Mengzhen; Chen, Gang; Wang, Xiao-Feng; Fu, Xueqi; Kitao, Osamu; Tamiaki, Hitoshi; Sakai, Kotowa; Ikeuchi, Toshitaka; Sasaki, Shin-Ichi

    2017-08-10

    Solid-state chlorophyll solar cells (CSCs) employing a carboxylated chlorophyll derivative, methyl trans-3 2 -carboxypyropheophorbide a, as a light-harvesting dye sensitizer chlorophyll (DSC) deposited on mesoporous TiO 2 , on which four zinc hydroxylated chlorophyll derivatives were spin-coated for hole transporter chlorophylls (HTCs), are described. Key parameters, including the effective carrier mobility of the HTC films, as determined by the space charge-limited current method, and the frontier molecular orbitals of these DSCs and HTCs, as estimated from cyclic voltammetry and electronic absorption spectra, suggest that both charge separation and carrier transport are favorable. The power conversion efficiencies (PCEs) of the present CSCs with fluorine-doped tin oxide (FTO)/TiO 2 /DSC/HTCs/Ag were determined to follow the order of HTC-1>HTC-2>HTC-3>HTC-4, which coincided perfectly with the order of their hole mobilities. The maximum PCE achieved was 0.86 % with HTC-1. The photovoltaic devices studied herein with two types of chlorophyll derivatives as dye sensitizers and hole transporters provide a unique solution for the utilization of solar energy with a view to truly realizing "green energy". © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Deep Learning Based Solar Flare Forecasting Model. I. Results for Line-of-sight Magnetograms

    NASA Astrophysics Data System (ADS)

    Huang, Xin; Wang, Huaning; Xu, Long; Liu, Jinfu; Li, Rong; Dai, Xinghua

    2018-03-01

    Solar flares originate from the release of the energy stored in the magnetic field of solar active regions, the triggering mechanism for these flares, however, remains unknown. For this reason, the conventional solar flare forecast is essentially based on the statistic relationship between solar flares and measures extracted from observational data. In the current work, the deep learning method is applied to set up the solar flare forecasting model, in which forecasting patterns can be learned from line-of-sight magnetograms of solar active regions. In order to obtain a large amount of observational data to train the forecasting model and test its performance, a data set is created from line-of-sight magnetogarms of active regions observed by SOHO/MDI and SDO/HMI from 1996 April to 2015 October and corresponding soft X-ray solar flares observed by GOES. The testing results of the forecasting model indicate that (1) the forecasting patterns can be automatically reached with the MDI data and they can also be applied to the HMI data; furthermore, these forecasting patterns are robust to the noise in the observational data; (2) the performance of the deep learning forecasting model is not sensitive to the given forecasting periods (6, 12, 24, or 48 hr); (3) the performance of the proposed forecasting model is comparable to that of the state-of-the-art flare forecasting models, even if the duration of the total magnetograms continuously spans 19.5 years. Case analyses demonstrate that the deep learning based solar flare forecasting model pays attention to areas with the magnetic polarity-inversion line or the strong magnetic field in magnetograms of active regions.

  3. Solar selective performance of metal nitride/oxynitride based magnetron sputtered thin film coatings: a comprehensive review

    NASA Astrophysics Data System (ADS)

    Ibrahim, Khalil; Taha, Hatem; Mahbubur Rahman, M.; Kabir, Humayun; Jiang, Zhong-Tao

    2018-03-01

    Since solar-thermal collectors are considered to be the most direct way of converting solar energy into usable forms, in the last few years growing attention has been paid to the development of transition metal nitride and metal oxynitride based thin film selective surfaces for solar-thermal collectors, in order to harvest more solar energy. A solar-thermal energy system, generally, shows very high solar absorption of incident solar radiation from the solar-thermal collectors in the visible range (0.3 to 2.5 μm) and extremely low thermal losses through emission (or high reflection) in the infrared region (≥2.5 μm). The efficiency of a solar-thermal energy conversion system can be improved by the use of solar selective surfaces consisting of novel metallic nanoparticles embedded in metal nitride/oxynitride systems. In order to enhance the effectiveness of solar-thermal devices, solar selective surfaces with high thermal stability are a prerequisite. Over the years, substantial efforts have been made in the field of solar selective surfaces to attain higher solar absorptance and lower thermal emittance in high temperature (above 400 °C) applications. In this article, we review the present state-of-the-art transition metal nitride and/or oxynitride based vacuum sputtered nanostructured thin film coatings, with respect to their optical and solar selective surface applications. We have also summarized the solar selectivity data from recently published investigations, including discussion on some potential applications for these materials.

  4. Investigation of colloidal PbS quantum dot-based solar cells with near infrared emission.

    PubMed

    Lim, Sungoh; Kim, Yohan; Lee, Jeongno; Han, Chul Jong; Kang, Jungwon; Kim, Jiwan

    2014-12-01

    Colloidal quantum dots (QD)-based solar cells with near infrared (NIR) emission have been investigated. Lead sulfide (PbS) QDs, which have narrow band-gap and maximize the absorption of NIR spectrum, were chosen as active materials for efficient solar cells. The inverted structure of indium tin oxide/titanium dioxide/PbS QDs/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)/silver (ITO/TiO2/PbS QDs/ PSS/Ag) was applied for favorable electron and hole seperation from the PbS QD. Through the ligand exchange by 1,2-Ethanedithiol (EDT), the interparticle distance of the PbS QDs in thin film became closer and the performance of the PbS QD-based solar cells was improved. Our PbS QD-based inverted solar cells showed open circuit voltages (V(oc)) of 0.33 V, short circuit current density (J(sc)) of 10.89 mA/cm2, fill factor (FF) of 30%, and power conversion efficiency (PCE) of 1.11%. In our PbS QD-based multifunctional solar cell, the NIR light emission intensity was simply detected with photodiode system, which implies the potential of multi-functional diode device for various applications.

  5. Leveraging the Polar Cap: Ground-Based Measurements of the Solar Wind

    NASA Astrophysics Data System (ADS)

    Urban, K. D.; Gerrard, A. J.; Weatherwax, A. T.; Lanzerotti, L. J.; Patterson, J. D.

    2016-12-01

    In this study, we look at and identify relationships between solar wind quantities that have previously been shown to have direct access into the very high-latitude polar cap as measured by ground-based riometers and magnetometers in Antarctica: ultra-low frequency (ULF) power in the interplanetary magnetic field (IMF) Bz component and solar energetic proton (SEP) flux (Urban [2016] and Patterson et al. [2001], respectively). It is shown that such solar wind and ground-based observations can be used to infer the hydromagnetic structure and magnetospheric mapping of the polar cap region in a data-driven manner, and that high-latitude ground-based instrumentation can be used to infer concurrent various state parameters of the geospace environment.

  6. Thiophene dendrimer-based low donor content solar cells

    NASA Astrophysics Data System (ADS)

    Stoltzfus, Dani M.; Ma, Chang-Qi; Nagiri, Ravi C. R.; Clulow, Andrew J.; Bäuerle, Peter; Burn, Paul L.; Gentle, Ian R.; Meredith, Paul

    2016-09-01

    Low donor content solar cells containing polymeric and non-polymeric donors blended with fullerenes have been reported to give rise to efficient devices. In this letter, we report that a dendrimeric donor can also be used in solution-processed low donor content devices when blended with a fullerene. A third generation dendrimer containing 42 thiophene units (42T) was found to give power conversion efficiencies of up to 3.5% when blended with PC70BM in optimized devices. The best efficiency was measured with 10 mole percent (mol. %) of 42T in PC70BM and X-ray reflectometry showed that the blends were uniform. Importantly, while 42T comprised 10 mol. % of the film, it made up 31% of the film by volume. Finally, it was found that solvent annealing was required to achieve the largest open circuit voltage and highest device efficiencies.

  7. Satellite-based trends of solar radiation and cloud parameters in Europe

    NASA Astrophysics Data System (ADS)

    Pfeifroth, Uwe; Bojanowski, Jedrzej S.; Clerbaux, Nicolas; Manara, Veronica; Sanchez-Lorenzo, Arturo; Trentmann, Jörg; Walawender, Jakub P.; Hollmann, Rainer

    2018-04-01

    Solar radiation is the main driver of the Earth's climate. Measuring solar radiation and analysing its interaction with clouds are essential for the understanding of the climate system. The EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) generates satellite-based, high-quality climate data records, with a focus on the energy balance and water cycle. Here, multiple of these data records are analyzed in a common framework to assess the consistency in trends and spatio-temporal variability of surface solar radiation, top-of-atmosphere reflected solar radiation and cloud fraction. This multi-parameter analysis focuses on Europe and covers the time period from 1992 to 2015. A high correlation between these three variables has been found over Europe. An overall consistency of the climate data records reveals an increase of surface solar radiation and a decrease in top-of-atmosphere reflected radiation. In addition, those trends are confirmed by negative trends in cloud cover. This consistency documents the high quality and stability of the CM SAF climate data records, which are mostly derived independently from each other. The results of this study indicate that one of the main reasons for the positive trend in surface solar radiation since the 1990's is a decrease in cloud coverage even if an aerosol contribution cannot be completely ruled out.

  8. Solar cell options based on different geographical locations and wall inclination

    NASA Astrophysics Data System (ADS)

    Ma, Jie

    2018-05-01

    Two major trends in the development of contemporary solar energy science and technology [1]: First, the combination of light and point, the second is the combination of solar energy and construction. A large number of houses at the top of the installation of solar water heaters and other primary solar energy utilization equipment can no longer meet the needs of the majority of users, people pay more attention to the ventilation and heating of housing and solar power supply and other integrated multi-purpose building construction. Under the condition of simplification, this model gives the options of laying suitable solar cells for houses with different geographical positions and different inclination angles according to the actual situation. Based on our model, firstly we calculate the wall radiation according to the model (WRCM) to get the light radiation of the wall of the house, and then according to the power generation model (PGM), we can calculate the output of several types of batteries in the selected range. Finally, through the economic benefits mode l (EBM), we get the economic benefits of each type of battery in different places, and then we can choose the most suitable battery type. At the end of the article, we take Datong, Shanxi Province as an example, and substitute the relevant data from online search into the model. Compared with the actual situation, we verify that the model has good applicability.

  9. Floating rGO-based black membranes for solar driven sterilization.

    PubMed

    Zhang, Yao; Zhao, Dengwu; Yu, Fan; Yang, Chao; Lou, Jinwei; Liu, Yanming; Chen, Yingying; Wang, Zhongyong; Tao, Peng; Shang, Wen; Wu, Jianbo; Song, Chengyi; Deng, Tao

    2017-12-14

    This paper presents a new steam sterilization approach that uses a solar-driven evaporation system at the water/air interface. Compared to the conventional solar autoclave, this new steam sterilization approach via interfacial evaporation requires no complex system design to bear high steam pressure. In such a system, a reduced graphene oxide/polytetrafluoroethylene composite membrane floating at the water/air interface serves as a light-to-heat conversion medium to harvest and convert incident solar light into localized heat. Such localized heat raises the temperature of the membrane substantially and helps generate steam with a temperature higher than 120 °C. A sterilization device that takes advantage of the interfacial solar-driven evaporation system was built and its successful sterilization capability was demonstrated through both chemical and biological sterilization tests. The interfacial evaporation-based solar driven sterilization approach offers a potential low cost solution to meet the need for sterilization in undeveloped areas that lack electrical power but have ample solar radiation.

  10. Solar Power Satellites: Reconsideration as Renewable Energy Source Based on Novel Approaches

    NASA Astrophysics Data System (ADS)

    Ellery, Alex

    2017-04-01

    Solar power satellites (SPS) are a solar energy generation mechanism that captures solar energy in space and converts this energy into microwave for transmission to Earth-based rectenna arrays. They offer a constant, high integrated energy density of 200 W/m2 compared to <10 W/m2 for other renewable energy sources. Despite this promise as a clean energy source, SPS have been relegated out of consideration due to their enormous cost and technological challenge. It has been suggested that for solar power satellites to become economically feasible, launch costs must decrease from their current 20,000/kg to <200/kg. Even with the advent of single-stage-to-orbit launchers which propose launch costs dropping to 2,000/kg, this will not be realized. Yet, the advantages of solar power satellites are many including the provision of stable baseload power. Here, I present a novel approach to reduce the specific cost of solar power satellites to 1/kg by leveraging two enabling technologies - in-situ resource utilization of lunar material and 3D printing of this material. Specifically, we demonstrate that electric motors may be constructed from lunar material through 3D printing representing a major step towards the development of self-replicating machines. Such machines have the capacity to build solar power satellites on the Moon, thereby bypassing the launch cost problem. The productive capacity of self-replicating machines favours the adoption of large constellations of small solar power satellites. This opens up additional clean energy options for combating climate change by meeting the demands for future global energy.

  11. High-efficiency dye-sensitized solar cells with ferrocene-based electrolytes.

    PubMed

    Daeneke, Torben; Kwon, Tae-Hyuk; Holmes, Andrew B; Duffy, Noel W; Bach, Udo; Spiccia, Leone

    2011-03-01

    Dye-sensitized solar cells based on iodide/triiodide (I(-)/I(3)(-)) electrolytes are viable low-cost alternatives to conventional silicon solar cells. However, as well as providing record efficiencies of up to 12.0%, the use of I(-)/I(3)(-) in such solar cells also brings about certain limitations that stem from its corrosive nature and complex two-electron redox chemistry. Alternative redox mediators have been investigated, but these generally fall well short of matching the performance of conventional I(-)/I(3)(-) electrolytes. Here, we report energy conversion efficiencies of 7.5% (simulated sunlight, AM1.5, 1,000 W m(-2)) for dye-sensitized solar cells combining the archetypal ferrocene/ferrocenium (Fc/Fc(+)) single-electron redox couple with a novel metal-free organic donor-acceptor sensitizer (Carbz-PAHTDTT). These Fc/Fc(+)-based devices exceed the efficiency achieved for devices prepared using I(-)/I(3)(-) electrolytes under comparable conditions, revealing the great potential of ferrocene-based electrolytes in future dye-sensitized solar cells applications. This improvement results from a more favourable matching of the redox potential of the ferrocene couple with that of the new donor-acceptor sensitizer.

  12. A Comparison between Physics-based and Polytropic MHD Models for Stellar Coronae and Stellar Winds of Solar Analogs

    SciTech Connect

    Cohen, O.

    The development of the Zeeman–Doppler Imaging (ZDI) technique has provided synoptic observations of surface magnetic fields of low-mass stars. This led the stellar astrophysics community to adopt modeling techniques that have been used in solar physics using solar magnetograms. However, many of these techniques have been neglected by the solar community due to their failure to reproduce solar observations. Nevertheless, some of these techniques are still used to simulate the coronae and winds of solar analogs. Here we present a comparative study between two MHD models for the solar corona and solar wind. The first type of model is amore » polytropic wind model, and the second is the physics-based AWSOM model. We show that while the AWSOM model consistently reproduces many solar observations, the polytropic model fails to reproduce many of them, and in the cases where it does, its solutions are unphysical. Our recommendation is that polytropic models, which are used to estimate mass-loss rates and other parameters of solar analogs, must first be calibrated with solar observations. Alternatively, these models can be calibrated with models that capture more detailed physics of the solar corona (such as the AWSOM model) and that can reproduce solar observations in a consistent manner. Without such a calibration, the results of the polytropic models cannot be validated, but they can be wrongly used by others.« less

  13. Thermal stability of photovoltaic a-Si:H determined by neutron reflectometry

    SciTech Connect

    Qviller, A. J., E-mail: atlejq@ife.no; Haug, H.; You, C. C.

    2014-12-08

    Neutron and X-ray reflectometry were used to determine the layer structure and hydrogen content of thin films of amorphous silicon (a-Si:H) deposited onto crystalline silicon (Si) wafers for surface passivation in solar cells. The combination of these two reflectometry techniques is well suited for non-destructive probing of the structure of a-Si:H due to being able to probe buried interfaces and having sub-nanometer resolution. Neutron reflectometry is also unique in its ability to allow determination of density gradients of light elements such as hydrogen (H). The neutron scattering contrast between Si and H is strong, making it possible to determine themore » H concentration in the deposited a-Si:H. In order to correlate the surface passivation properties supplied by the a-Si:H thin films, as quantified by obtainable effective minority carrier lifetime, photoconductance measurements were also performed. It is shown that the minority carrier lifetime falls sharply when H has been desorbed from a-Si:H by annealing.« less

  14. The Simulation of the Recharging Method Based on Solar Radiation for an Implantable Biosensor

    PubMed Central

    Li, Yun; Song, Yong; Kong, Xianyue; Li, Maoyuan; Zhao, Yufei; Hao, Qun; Gao, Tianxin

    2016-01-01

    A method of recharging implantable biosensors based on solar radiation is proposed. Firstly, the models of the proposed method are developed. Secondly, the recharging processes based on solar radiation are simulated using Monte Carlo (MC) method and the energy distributions of sunlight within the different layers of human skin have been achieved and discussed. Finally, the simulation results are verified experimentally, which indicates that the proposed method will contribute to achieve a low-cost, convenient and safe method for recharging implantable biosensors. PMID:27626422

  15. Satellite-based climate data records of surface solar radiation from the CM SAF

    NASA Astrophysics Data System (ADS)

    Trentmann, Jörg; Cremer, Roswitha; Kothe, Steffen; Müller, Richard; Pfeifroth, Uwe

    2017-04-01

    The incoming surface solar radiation has been defined as an essential climate variable by GCOS. Long term monitoring of this part of the earth's energy budget is required to gain insights on the state and variability of the climate system. In addition, climate data sets of surface solar radiation have received increased attention over the recent years as an important source of information for solar energy assessments, for crop modeling, and for the validation of climate and weather models. The EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) is deriving climate data records (CDRs) from geostationary and polar-orbiting satellite instruments. Within the CM SAF these CDRs are accompanied by operational data at a short time latency to be used for climate monitoring. All data from the CM SAF is freely available via www.cmsaf.eu. Here we present the regional and the global climate data records of surface solar radiation from the CM SAF. The regional climate data record SARAH (Surface Solar Radiation Dataset - Heliosat, doi: 10.5676/EUM_SAF_CM/SARAH/V002) is based on observations from the series of Meteosat satellites. SARAH provides 30-min, daily- and monthly-averaged data of the effective cloud albedo, the solar irradiance (incl. spectral information), the direct solar radiation (horizontal and normal), and the sunshine duration from 1983 to 2015 for the full view of the Meteosat satellite (i.e, Europe, Africa, parts of South America, and the Atlantic ocean). The data sets are generated with a high spatial resolution of 0.05° allowing for detailed regional studies. The global climate data record CLARA (CM SAF Clouds, Albedo and Radiation dataset from AVHRR data, doi: 10.5676/EUM_SAF_CM/CLARA_AVHRR/V002) is based on observations from the series of AVHRR satellite instruments. CLARA provides daily- and monthly-averaged global data of the solar irradiance (SIS) from 1982 to 2015 with a spatial resolution of 0.25°. In addition to the solar surface

  16. Temperature based daily incoming solar radiation modeling based on gene expression programming, neuro-fuzzy and neural network computing techniques.

    NASA Astrophysics Data System (ADS)

    Landeras, G.; López, J. J.; Kisi, O.; Shiri, J.

    2012-04-01

    The correct observation/estimation of surface incoming solar radiation (RS) is very important for many agricultural, meteorological and hydrological related applications. While most weather stations are provided with sensors for air temperature detection, the presence of sensors necessary for the detection of solar radiation is not so habitual and the data quality provided by them is sometimes poor. In these cases it is necessary to estimate this variable. Temperature based modeling procedures are reported in this study for estimating daily incoming solar radiation by using Gene Expression Programming (GEP) for the first time, and other artificial intelligence models such as Artificial Neural Networks (ANNs), and Adaptive Neuro-Fuzzy Inference System (ANFIS). Traditional temperature based solar radiation equations were also included in this study and compared with artificial intelligence based approaches. Root mean square error (RMSE), mean absolute error (MAE) RMSE-based skill score (SSRMSE), MAE-based skill score (SSMAE) and r2 criterion of Nash and Sutcliffe criteria were used to assess the models' performances. An ANN (a four-input multilayer perceptron with ten neurons in the hidden layer) presented the best performance among the studied models (2.93 MJ m-2 d-1 of RMSE). A four-input ANFIS model revealed as an interesting alternative to ANNs (3.14 MJ m-2 d-1 of RMSE). Very limited number of studies has been done on estimation of solar radiation based on ANFIS, and the present one demonstrated the ability of ANFIS to model solar radiation based on temperatures and extraterrestrial radiation. By the way this study demonstrated, for the first time, the ability of GEP models to model solar radiation based on daily atmospheric variables. Despite the accuracy of GEP models was slightly lower than the ANFIS and ANN models the genetic programming models (i.e., GEP) are superior to other artificial intelligence models in giving a simple explicit equation for the

  17. Characterizing a Model of Coronal Heating and Solar Wind Acceleration Based on Wave Turbulence.

    NASA Astrophysics Data System (ADS)

    Downs, C.; Lionello, R.; Mikic, Z.; Linker, J.; Velli, M.

    2014-12-01

    Understanding the nature of coronal heating and solar wind acceleration is a key goal in solar and heliospheric research. While there have been many theoretical advances in both topics, including suggestions that they may be intimately related, the inherent scale coupling and complexity of these phenomena limits our ability to construct models that test them on a fundamental level for realistic solar conditions. At the same time, there is an ever increasing impetus to improve our spaceweather models, and incorporating treatments for these processes that capture their basic features while remaining tractable is an important goal. With this in mind, I will give an overview of our exploration of a wave-turbulence driven (WTD) model for coronal heating and solar wind acceleration based on low-frequency Alfvénic turbulence. Here we attempt to bridge the gap between theory and practical modeling by exploring this model in 1D HD and multi-dimensional MHD contexts. The key questions that we explore are: What properties must the model possess to be a viable model for coronal heating? What is the influence of the magnetic field topology (open, closed, rapidly expanding)? And can we simultaneously capture coronal heating and solar wind acceleration with such a quasi-steady formulation? Our initial results suggest that a WTD based formulation performs adequately for a variety of solar and heliospheric conditions, while significantly reducing the number of free parameters when compared to empirical heating and solar wind models. The challenges, applications, and future prospects of this type of approach will also be discussed.

  18. On-orbit degradation of recent space-based solar instruments and understanding of the degradation processes

    NASA Astrophysics Data System (ADS)

    Meftah, M.; Dominique, M.; BenMoussa, A.; Dammasch, I. E.; Bolsée, D.; Pereira, N.; Damé, L.; Bekki, S.; Hauchecorne, A.

    2017-05-01

    The space environment is considered hazardous to spacecraft, resulting in materials degradation. Understanding the degradation of space-based instruments is crucial in order to achieve the scientific objectives, which are derived from these instruments. This paper discusses the on-orbit performance degradation of recent spacebased solar instruments. We will focus on the instruments of three space-based missions such as the Project for On-Board Autonomy 2 (PROBA2) spacecraft, the Solar Monitoring Observatory (SOLAR) payload onboard the Columbus science Laboratory of the International Space Station (ISS) and the PICARD spacecraft. Finally, this paper intends to understand the degradation processes of these space-based solar instruments.

  19. A Temperature-Based Model for Estimating Monthly Average Daily Global Solar Radiation in China

    PubMed Central

    Li, Huashan; Cao, Fei; Wang, Xianlong; Ma, Weibin

    2014-01-01

    Since air temperature records are readily available around the world, the models based on air temperature for estimating solar radiation have been widely accepted. In this paper, a new model based on Hargreaves and Samani (HS) method for estimating monthly average daily global solar radiation is proposed. With statistical error tests, the performance of the new model is validated by comparing with the HS model and its two modifications (Samani model and Chen model) against the measured data at 65 meteorological stations in China. Results show that the new model is more accurate and robust than the HS, Samani, and Chen models in all climatic regions, especially in the humid regions. Hence, the new model can be recommended for estimating solar radiation in areas where only air temperature data are available in China. PMID:24605046

  20. The I-V Measurement System for Solar Cells Based on MCU

    NASA Astrophysics Data System (ADS)

    Fengxiang, Chen; Yu, Ai; Jiafu, Wang; Lisheng, Wang

    2011-02-01

    In this paper, an I-V measurement system for solar cells based on Single-chip Microcomputer (MCU) is presented. According to the test principles of solar cells, this measurement system mainly comprises of two parts—data collecting, data processing and displaying. The MCU mainly used as to acquire data, then the collecting results is sent to the computer by serial port. The I-V measurement results of our test system are shown in the human-computer interaction interface based on our hardware circuit. By comparing the test results of our I-V tester and the results of other commercial I-V tester, we found errors for most parameters are less than 5%, which shows our I-V test result is reliable. Because the MCU can be applied in many fields, this I-V measurement system offers a simple prototype for portable I-V tester for solar cells.

  1. Experimental study of refrigeration performance based on linear Fresnel solar thermal photovoltaic system

    NASA Astrophysics Data System (ADS)

    Song, Jinghui; Yuan, Hui; Xia, Yunfeng; Kan, Weimin; Deng, Xiaowen; Liu, Shi; Liang, Wanlong; Deng, Jianhua

    2018-03-01

    This paper introduces the working principle and system constitution of the linear Fresnel solar lithium bromide absorption refrigeration cycle, and elaborates several typical structures of absorption refrigeration cycle, including single-effect, two-stage cycle and double-effect lithium bromide absorption refrigeration cycle A 1.n effect absorption chiller system based on the best parameters was introduced and applied to a linear Fresnel solar absorption chiller system. Through the field refrigerator performance test, the results show: Based on this heat cycle design and processing 1.n lithium bromide absorption refrigeration power up to 35.2KW, It can meet the theoretical expectations and has good flexibility and reliability, provides guidance for the use of solar thermal energy.

  2. Development of a digital solar simulator based on full-bridge converter

    NASA Astrophysics Data System (ADS)

    Liu, Chen; Feng, Jian; Liu, Zhilong; Tong, Weichao; Ji, Yibo

    2014-02-01

    With the development of solar photovoltaic, distribution schemes utilized in power grid had been commonly application, and photovoltaic (PV) inverter is an essential equipment in grid. In this paper, a digital solar simulator based on full-bridge structure is presented. The output characteristic curve of system is electrically similar to silicon solar cells, which can greatly simplify research methods of PV inverter, improve the efficiency of research and development. The proposed simulator consists on a main control board based on TM320F28335, phase-shifted zero-voltage-switching (ZVS) DC-DC full-bridge converter and voltage and current sampling circuit, that allows emulating the voltage-current curve with the open-circuit voltage (Voc) of 900V and the short-circuit current (Isc) of 18A .When the system connected to a PV inverter, the inverter can quickly track from the open-circuit to the maximum power point and keep stability.

  3. Fiber-Based, Double-Sided, Reduced Graphene Oxide Films for Efficient Solar Vapor Generation.

    PubMed

    Guo, Ankang; Ming, Xin; Fu, Yang; Wang, Gang; Wang, Xianbao

    2017-09-06

    Solar vapor generation is a promising and whole new branch of photothermal conversion for harvesting solar energy. Various materials and devices for solar thermal conversion were successively produced and reported for higher solar energy utilization in the past few years. Herein, a compact device of reduced graphene oxides (rGO) and paper fibers was designed and assembled for efficient solar steam generation under light illumination, and it consists of water supply pipelines (WSP), a thermal insulator (TI) and a double-sided absorbing film (DSF). Heat localization is enabled by the black DSF due to its broad absorption of sunlight. More importantly, the heat transfer, from the hot DSF to the cold base fluid (water), was suppressed by TI with a low thermal conductivity. Meanwhile, bulk water was continuously transported to the DSF by WSP through TI, which was driven by the surface energy and surface tension based on the capillary effect. The effects of reduction degrees of rGO on the photothermal conversion were explored, and the evaporation efficiency reached 89.2% under one sun with 60 mg rGO. This new microdevice provided a basic technical support for distillation, desalination, sewage treatment, and related technologies.

  4. Low temperature surface passivation of crystalline silicon and its application to interdigitated back contact silicon heterojunction (ibc-shj) solar cell

    NASA Astrophysics Data System (ADS)

    Shu, Zhan

    With the absence of shading loss together with improved quality of surface passivation introduced by low temperature processed amorphous silicon crystalline silicon (a-Si:H/c-Si) heterojunction, the interdigitated back contact silicon heterojunction (IBC-SHJ) solar cell exhibits a potential for higher conversion efficiency and lower cost than a traditional front contact diffused junction solar cell. In such solar cells, the front surface passivation is of great importance to achieve both high open-circuit voltage (Voc) and short-circuit current (Jsc). Therefore, the motivation of this work is to develop a low temperature processed structure for the front surface passivation of IBC-SHJ solar cells, which must have an excellent and stable passivation quality as well as a good anti-reflection property. Four different thin film materials/structures were studied and evaluated for this purpose, namely: amorphous silicon nitride (a-SiNx:H), thick amorphous silicon film (a-Si:H), amorphous silicon/silicon nitride/silicon carbide (a-Si:H/a-SiN x:H/a-SiC:H) stack structure with an ultra-thin a-Si:H layer, and zinc sulfide (ZnS). It was demonstrated that the a-Si:H/a-SiNx:H/a-SiC:H stack surpasses other candidates due to both of its excellent surface passivation quality (SRV<5 cm/s) and lower absorption losses. The low recombination rate at the stack structure passivated c-Si surface is found to be resulted from (i) field effect passivation due to the positive fixed charge (Q fix~1x1011 cm-2 with 5 nm a-Si:H layer) in a-SiNx:H as measured from capacitance-voltage technique, and (ii) reduced defect state density (mid-gap Dit~4x1010 cm-2eV-1) at a-Si:H/c-Si interface provided by a 5 nm thick a-Si:H layer, as characterized by conductance-frequency measurements. Paralleled with the experimental studies, a computer program was developed in this work based on the extended Shockley-Read-Hall (SRH) model of surface recombination. With the help of this program, the experimental

  5. Antireflection coatings based on fluoride formulations for organic solar cells

    NASA Astrophysics Data System (ADS)

    Suleimanov, S. Kh.; Berger, P.; Dyskin, V. G.; Dzhanklych, M. U.; Bugakov, A. G.; Dudko, O. A.; Kulagina, N. A.; Kim, M.

    2016-04-01

    An alloy of a mixture of fluorides MgF2 and AlF3 with CaF2 has been obtained in a 3-kW solar furnace. It was supposed that a minor CaF2 additive compensates for the tensile stresses appearing in thin MgF2 and AlF3 films, with their mechanical properties being thereby improved. The results of X-ray phase analysis demonstrated that both components of the mixture are present in the alloy, while the complex oxide CaAl4O7, the formation of which is attributed to the melting in air, is only identified in AlF3: CaF2 = 95: 5 (wt %). The increase in the transmittance of glass and polyethylene terephthalate upon deposition onto their surface of a thin film of the material synthesized in the study is due to the optical properties of AlF3 and MgF2.

  6. Light-Independent Ionic Transport in Inorganic Perovskite and Ultrastable Cs-Based Perovskite Solar Cells.

    PubMed

    Zhou, Wenke; Zhao, Yicheng; Zhou, Xu; Fu, Rui; Li, Qi; Zhao, Yao; Liu, Kaihui; Yu, Dapeng; Zhao, Qing

    2017-09-07

    Due to light-induced effects in CH 3 NH 3 -based perovskites, such as ion migration, defects formation, and halide segregation, the degradation of CH 3 NH 3 -based perovskite solar cells under maximum power point is generally implicated. Here we demonstrated that the effect of light-enhanced ion migration in CH 3 NH 3 PbI 3 can be eliminated by inorganic Cs substitution, leading to an ultrastable perovskite solar cell. Quantitatively, the ion migration barrier for CH 3 NH 3 PbI 3 is 0.62 eV under dark conditions, larger than that of CsPbI 2 Br (0.45 eV); however, it reduces to 0.07 eV for CH 3 NH 3 PbI 3 under illumination, smaller than that for CsPbI 2 Br (0.43 eV). Meanwhile, photoinduced halide segregation is also suppressed in Cs-based perovskites. Cs-based perovskite solar cells retained >99% of the initial efficiency (10.3%) after 1500 h of maximum power point tracking under AM1.5G illumination, while CH 3 NH 3 PbI 3 solar cells degraded severely after 50 h of operation. Our work reveals an uncovered mechanism for stability improvement by inorganic cation substitution in perovskite-based optoelectronic devices.

  7. Molten salt based nanofluids based on solar salt and alumina nanoparticles: An industrial approach

    NASA Astrophysics Data System (ADS)

    Muñoz-Sánchez, Belén; Nieto-Maestre, Javier; Guerreiro, Luis; Julia, José Enrique; Collares-Pereira, Manuel; García-Romero, Ana

    2017-06-01

    Thermal Energy Storage (TES) and its associated dispatchability is extremely important in Concentrated Solar Power (CSP) plants since it represents the main advantage of CSP technology in relation to other renewable energy sources like photovoltaic (PV). Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 600°C. Their main problems are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve the thermal properties of molten salts is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. Additionally, the use of molten salt based nanofluids as TES materials and Heat Transfer Fluid (HTF) has been attracting great interest in recent years. The addition of tiny amounts of nanoparticles to the base salt can improve its specific heat as shown by different authors1-3. The application of these nano-enhanced materials can lead to important savings on the investment costs in new TES systems for CSP plants. However, there is still a long way to go in order to achieve a commercial product. In this sense, the improvement of the stability of the nanofluids is a key factor. The stability of nanofluids will depend on the nature and size of the nanoparticles, the base salt and the interactions between them. In this work, Solar Salt (SS) commonly used in CSP plants (60% NaNO3 + 40% KNO3 wt.) was doped with alumina nanoparticles (ANPs) at a solid mass concentration of 1% wt. at laboratory scale. The tendency of nanoparticles to agglomeration and sedimentation is tested in the molten state by analyzing their size and concentration through the time. The specific heat of the nanofluid at 396 °C (molten state) is measured at different times (30 min, 1 h, 5 h). Further research is needed to understand the mechanisms of agglomeration. A good understanding of the interactions between the nanoparticle surface and the ionic media would provide

  8. Spectroscopic Measurements of the Ion Velocity Distribution at the Base of the Fast Solar Wind

    NASA Astrophysics Data System (ADS)

    Jeffrey, Natasha L. S.; Hahn, Michael; Savin, Daniel W.; Fletcher, Lyndsay

    2018-03-01

    In situ measurements of the fast solar wind reveal non-thermal distributions of electrons, protons, and minor ions extending from 0.3 au to the heliopause. The physical mechanisms responsible for these non-thermal properties and the location where these properties originate remain open questions. Here, we present spectroscopic evidence, from extreme ultraviolet spectroscopy, that the velocity distribution functions (VDFs) of minor ions are already non-Gaussian at the base of the fast solar wind in a coronal hole, at altitudes of <1.1 R ⊙. Analysis of Fe, Si, and Mg spectral lines reveals a peaked line-shape core and broad wings that can be characterized by a kappa VDF. A kappa distribution fit gives very small kappa indices off-limb of κ ≈ 1.9–2.5, indicating either (a) ion populations far from thermal equilibrium, (b) fluid motions such as non-Gaussian turbulent fluctuations or non-uniform wave motions, or (c) some combination of both. These observations provide important empirical constraints for the source region of the fast solar wind and for the theoretical models of the different acceleration, heating, and energy deposition processes therein. To the best of our knowledge, this is the first time that the ion VDF in the fast solar wind has been probed so close to its source region. The findings are also a timely precursor to the upcoming 2018 launch of the Parker Solar Probe, which will provide the closest in situ measurements of the solar wind at approximately 0.04 au (8.5 solar radii).

  9. Highly improved passivation of c-Si surfaces using a gradient i a-Si:H layer

    NASA Astrophysics Data System (ADS)

    Lee, Soonil; Ahn, Jaehyun; Mathew, Leo; Rao, Rajesh; Zhang, Zhongjian; Kim, Jae Hyun; Banerjee, Sanjay K.; Yu, Edward T.

    2018-04-01

    Surface passivation using intrinsic a-Si:H (i a-Si:H) films plays a key role in high efficiency c-Si heterojunction solar cells. In this study, we demonstrate improved passivation quality using i a-Si:H films with a gradient-layered structure consisting of interfacial, transition, and capping layers deposited on c-Si surfaces. The H2 dilution ratio (R) during deposition was optimized individually for the interfacial and capping layers, which were separated by a transition layer for which R changed gradually between its values for the interfacial and capping layers. This approach yielded a significant reduction in surface carrier recombination, resulting in improvement of the minority carrier lifetime from 1480 μs for mono-layered i a-Si:H passivation to 2550 μs for the gradient-layered passivation approach.

  10. Materials, device, and interface engineering to improve polymer-based solar cells

    NASA Astrophysics Data System (ADS)

    Hau, Steven Kin

    The continued depletion of fossil fuel resources has lead to the rise in energy production costs which has lead to the search for an economically viable alternative energy source. One alternative of particular interest is solar energy. A promising alternative to inorganic materials is organic semiconductor polymer solar cells due to their advantages of being cheaper, light weight, flexible and made into large areas by roll-to-roll processing. In this dissertation, an integrated approach is taken to improve the overall performance of polymer-based solar cells by the development of new polymer materials, device architectures, and interface engineering of the contacts between layers. First, a new class of metallated conjugated polymers is explored as potential solar cell materials. Systematic modifications to the molecular units on the main chain of amorphous metallated Pt-polymers show a correlation that improving charge carrier mobility also improves solar cell performance leading to mobilities as high as 1 x 10-2 cm2/V·s and efficiencies as high as 4.1%. Second, an inverted device architecture using a more air stable electrode (Ag) is demonstrated to improve the ambient stability of unencapsulated P3HT:PCBM devices showing over 80% efficiency retention after 40 days of exposure. To further demonstrate the potential for roll-to-roll processing of polymer solar cells, solution processed Ag-nanoparticles were used to replace the vacuum deposited Ag anode electrode for inverted solar cells showing efficiencies as high as 3%. In addition, solution processed polymer based electrodes were demonstrated as a replacement to the expensive and brittle indium tin oxide showing efficiencies of 3% on flexible substrate solar cells. Third, interface engineering of the n-type (high temperature sol-gel processed TiO2 or ZnO, low temperature processed ZnO nanoparticles) electron selective metal oxide contacts in inverted solar cells with self-assembled monolayers (SAM) show improved

  11. Efficient iodine-free dye-sensitized solar cells employing truxene-based organic dyes.

    PubMed

    Zong, Xueping; Liang, Mao; Chen, Tao; Jia, Jiangnan; Wang, Lina; Sun, Zhe; Xue, Song

    2012-07-07

    Two new truxene-based organic sensitizers (M15 and M16) featuring high extinction coefficients were synthesized for dye-sensitized solar cells employing cobalt electrolyte. The M16-sensitized device displays a 7.6% efficiency at an irradiation of AM1.5 full sunlight.

  12. Data-driven agent-based modeling, with application to rooftop solar adoption

    SciTech Connect

    Zhang, Haifeng; Vorobeychik, Yevgeniy; Letchford, Joshua

    Agent-based modeling is commonly used for studying complex system properties emergent from interactions among many agents. We present a novel data-driven agent-based modeling framework applied to forecasting individual and aggregate residential rooftop solar adoption in San Diego county. Our first step is to learn a model of individual agent behavior from combined data of individual adoption characteristics and property assessment. We then construct an agent-based simulation with the learned model embedded in artificial agents, and proceed to validate it using a holdout sequence of collective adoption decisions. We demonstrate that the resulting agent-based model successfully forecasts solar adoption trends andmore » provides a meaningful quantification of uncertainty about its predictions. We utilize our model to optimize two classes of policies aimed at spurring solar adoption: one that subsidizes the cost of adoption, and another that gives away free systems to low-income house- holds. We find that the optimal policies derived for the latter class are significantly more efficacious, whereas the policies similar to the current California Solar Initiative incentive scheme appear to have a limited impact on overall adoption trends.« less

  13. Aqueous dye-sensitized solar cell electrolytes based on the ferricyanide-ferrocyanide redox couple.

    PubMed

    Daeneke, Torben; Uemura, Yu; Duffy, Noel W; Mozer, Attila J; Koumura, Nagatoshi; Bach, Udo; Spiccia, Leone

    2012-03-02

    Solar energy conversion efficiencies of over 4% have been achieved in DSCs constructed with aqueous electrolytes based on the ferricyanide-ferrocyanide redox couple, thereby avoiding the use of expensive, flammable and toxic solvents. This paradigm shift was made possible by the use of a hydrophobic organic carbazole dye. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Enhancing the Efficiency of Silicon-Based Solar Cells by the Piezo-Phototronic Effect.

    PubMed

    Zhu, Laipan; Wang, Longfei; Pan, Caofeng; Chen, Libo; Xue, Fei; Chen, Baodong; Yang, Leijing; Su, Li; Wang, Zhong Lin

    2017-02-28

    Although there are numerous approaches for fabricating solar cells, the silicon-based photovoltaics are still the most widely used in industry and around the world. A small increase in the efficiency of silicon-based solar cells has a huge economic impact and practical importance. We fabricate a silicon-based nanoheterostructure (p + -Si/p-Si/n + -Si (and n-Si)/n-ZnO nanowire (NW) array) photovoltaic device and demonstrate the enhanced device performance through significantly enhanced light absorption by NW array and effective charge carrier separation by the piezo-phototronic effect. The strain-induced piezoelectric polarization charges created at n-doped Si-ZnO interfaces can effectively modulate the corresponding band structure and electron gas trapped in the n + -Si/n-ZnO NW nanoheterostructure and thus enhance the transport process of local charge carriers. The efficiency of the solar cell was improved from 8.97% to 9.51% by simply applying a static compress strain. This study indicates that the piezo-phototronic effect can enhance the performance of a large-scale silicon-based solar cell, with great potential for industrial applications.

  15. Data-driven agent-based modeling, with application to rooftop solar adoption

    DOE PAGES

    Zhang, Haifeng; Vorobeychik, Yevgeniy; Letchford, Joshua; ...

    2016-01-25

    Agent-based modeling is commonly used for studying complex system properties emergent from interactions among many agents. We present a novel data-driven agent-based modeling framework applied to forecasting individual and aggregate residential rooftop solar adoption in San Diego county. Our first step is to learn a model of individual agent behavior from combined data of individual adoption characteristics and property assessment. We then construct an agent-based simulation with the learned model embedded in artificial agents, and proceed to validate it using a holdout sequence of collective adoption decisions. We demonstrate that the resulting agent-based model successfully forecasts solar adoption trends andmore » provides a meaningful quantification of uncertainty about its predictions. We utilize our model to optimize two classes of policies aimed at spurring solar adoption: one that subsidizes the cost of adoption, and another that gives away free systems to low-income house- holds. We find that the optimal policies derived for the latter class are significantly more efficacious, whereas the policies similar to the current California Solar Initiative incentive scheme appear to have a limited impact on overall adoption trends.« less

  16. 78 FR 28836 - Arlington Valley Solar Energy II, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-16

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-1430-000] Arlington Valley Solar Energy II, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request..., of Arlington Valley Solar Energy II, LLC's application for market-based rate authority, with an...

  17. 78 FR 34371 - Centinela Solar Energy, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-07

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-1561-000] Centinela Solar Energy, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... Centinela Solar Energy, LLC's application for market-based rate authority, with an accompanying rate...

  18. 76 FR 32188 - Hatch Solar Energy Center 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-03

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-3635-000] Hatch Solar Energy Center 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... Hatch Solar Energy Center 1, LLC's application for market-based rate authority, with an accompanying...

  19. 76 FR 44322 - Copper Mountain Solar 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-25

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-4055-000] Copper Mountain Solar 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... Copper Mountain Solar 1, LLC's application for market-based rate authority, with an accompanying rate...

  20. 77 FR 24697 - Cooper Mountain Solar 2, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-25

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-1566-000] Cooper Mountain Solar 2, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... Cooper Mountain Solar 2, LLC's application for market-based rate authority, with an accompanying rate...

  1. 76 FR 55377 - Bellevue Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-07

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-4380-000] Bellevue Solar, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket... Solar, LLC's application for market-based rate authority, with an accompanying rate tariff, noting that...

  2. 77 FR 48148 - Helvetia Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-13

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-2405-000] Helvetia Solar, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket... Solar, LLC's application for market-based rate authority, with an accompanying rate schedule, noting...

  3. 76 FR 55378 - Yamhill Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-07

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [ Docket No. ER11-4381-000] Yamhill Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket... Solar, LLC's application for market-based rate authority, with an accompanying rate tariff, noting that...

  4. 76 FR 63614 - Agua Caliente Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-13

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-21-000] Agua Caliente Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket... Caliente Solar, LLC's application for market-based rate authority, with an accompanying rate tariff, noting...

  5. 78 FR 46939 - Solar Partners II, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-02

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-2020-000 ] Solar Partners II, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket..., of Solar Partners II, LLC's application for market-based rate authority, with an accompanying rate...

  6. 77 FR 58827 - Catalina Solar, LLC; Supplemental Notice that Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-24

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-2627-000] Catalina Solar, LLC; Supplemental Notice that Initial Market- Based Rate Filing Includes Request for Blanket... Solar, LLC's application for market-based rate authority, with an accompanying rate schedule, noting...

  7. 76 FR 41240 - Mesquite Solar 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-13

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-3987-000] Mesquite Solar 1, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket... Solar 1, LLC's application for market-based rate authority, with an accompanying rate tariff, noting...

  8. 78 FR 5176 - CED White River Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-24

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-764-000] CED White River Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket... River Solar, LLC's application for market-based rate authority, with an accompanying rate schedule...

  9. 76 FR 30935 - Long Island Solar Farm, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-27

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-3589-000] Long Island Solar Farm, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket... Solar Farm, LLC's application for market-based rate authority, with an accompanying rate tariff, noting...

  10. 78 FR 34372 - Catalina Solar Lessee, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-07

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-1562-000] Catalina Solar Lessee, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... Catalina Solar Lessee, LLC's application for market-based rate authority, with an accompanying rate...

  11. 78 FR 62301 - Mountain View Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-15

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER14-21-000] Mountain View Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket... View Solar, LLC's application for market-based rate authority, with an accompanying rate schedule...

  12. 77 FR 20381 - Silver State Solar Power North, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-04

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-1316-000] Silver State Solar Power North, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... Silver State Solar Power North, LLC's application for market-based rate authority, with an accompanying...

  13. 76 FR 64341 - Silver State Solar Power North LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-18

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-32-000] Silver State Solar Power North LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... Silver State Solar Power North, LLC's application for market-based rate authority, with an accompanying...

  14. Solar-Iss a New Solar Reference Spectrum Covering the Far UV to the Infrared (165 to 3088 Nm) Based on Reanalyzed Solar/solspec Cycle 24 Observations

    NASA Astrophysics Data System (ADS)

    Damé, L.; Meftah, M.; Irbah, A.; Hauchecorne, A.; Bekki, S.; Bolsée, D.; Pereira, N.; Sluse, D.; Cessateur, G.

    2017-12-01

    Since April 5, 2008 and until February 15, 2017, the SOLSPEC (SOLar SPECtrometer) spectro-radiometer of the SOLAR facility on the International Space Station performed accurate measurements of Solar Spectral Irradiance (SSI) from the far ultraviolet to the infrared (165 nm to 3088 nm). These measurements, unique by their large spectral coverage and long time range, are of primary importance for a better understanding of solar physics and of the impact of solar variability on climate (via Earth's atmospheric photochemistry), noticeably through the "top-down" mechanism amplifying ultraviolet (UV) solar forcing effects on the climate (UV affects stratospheric dynamics and temperatures, altering interplanetary waves and weather patterns both poleward and downward to the lower stratosphere and troposphere regions). SOLAR/SOLSPEC, with almost 9 years of observations covering the essential of the unusual solar cycle 24 from minimum in 2008 to maximum, allowed to establish new reference solar spectra from UV to IR (165 to 3088 nm) at minimum (beginning of mission) and maximum of activity. The complete reanalysis was possible thanks to revised engineering corrections, improved calibrations and advanced procedures to account for thermal, aging and pointing corrections. The high quality and sensitivity of SOLSPEC data allow to follow temporal variability in UV but also in visible along the cycle. Uncertainties on these measurements are evaluated and results, absolute reference spectra and variability, are compared with other measurements (WHI, ATLAS-3, SCIAMACHY, SORCE/SOLSTICE, SORCE/SIM) and models (SATIRE-S, NRLSSI, NESSY)

  15. Compact solar autoclave based on steam generation using broadband light-harvesting nanoparticles.

    PubMed

    Neumann, Oara; Feronti, Curtis; Neumann, Albert D; Dong, Anjie; Schell, Kevin; Lu, Benjamin; Kim, Eric; Quinn, Mary; Thompson, Shea; Grady, Nathaniel; Nordlander, Peter; Oden, Maria; Halas, Naomi J

    2013-07-16

    The lack of readily available sterilization processes for medicine and dentistry practices in the developing world is a major risk factor for the propagation of disease. Modern medical facilities in the developed world often use autoclave systems to sterilize medical instruments and equipment and process waste that could contain harmful contagions. Here, we show the use of broadband light-absorbing nanoparticles as solar photothermal heaters, which generate high-temperature steam for a standalone, efficient solar autoclave useful for sanitation of instruments or materials in resource-limited, remote locations. Sterilization was verified using a standard Geobacillus stearothermophilus-based biological indicator.

  16. Automated recognition and characterization of solar active regions based on the SOHO/MDI images

    NASA Technical Reports Server (NTRS)

    Pap, J. M.; Turmon, M.; Mukhtar, S.; Bogart, R.; Ulrich, R.; Froehlich, C.; Wehrli, C.

    1997-01-01

    The first results of a new method to identify and characterize the various surface structures on the sun, which may contribute to the changes in solar total and spectral irradiance, are shown. The full disk magnetograms (1024 x 1024 pixels) of the Michelson Doppler Imager (MDI) experiment onboard SOHO are analyzed. Use of a Bayesian inference scheme allows objective, uniform, automated processing of a long sequence of images. The main goal is to identify the solar magnetic features causing irradiance changes. The results presented are based on a pilot time interval of August 1996.

  17. Solar cells based on InP/GaP/Si structure

    NASA Astrophysics Data System (ADS)

    Kvitsiani, O.; Laperashvil, D.; Laperashvili, T.; Mikelashvili, V.

    2016-10-01

    Solar cells (SCs) based on III-V semiconductors are reviewed. Presented work emphases on the Solar Cells containing Quantum Dots (QDs) for next-generation photovoltaics. In this work the method of fabrication of InP QDs on III-V semiconductors is investigated. The original method of electrochemical deposition of metals: indium (In), gallium (Ga) and of alloys (InGa) on the surface of gallium phosphide (GaP), and mechanism of formation of InP QDs on GaP surface is presented. The possibilities of application of InP/GaP/Si structure as SC are discussed, and the challenges arising is also considered.

  18. Compact solar autoclave based on steam generation using broadband light-harvesting nanoparticles

    PubMed Central

    Neumann, Oara; Feronti, Curtis; Neumann, Albert D.; Dong, Anjie; Schell, Kevin; Lu, Benjamin; Kim, Eric; Quinn, Mary; Thompson, Shea; Grady, Nathaniel; Nordlander, Peter; Oden, Maria; Halas, Naomi J.

    2013-01-01

    The lack of readily available sterilization processes for medicine and dentistry practices in the developing world is a major risk factor for the propagation of disease. Modern medical facilities in the developed world often use autoclave systems to sterilize medical instruments and equipment and process waste that could contain harmful contagions. Here, we show the use of broadband light-absorbing nanoparticles as solar photothermal heaters, which generate high-temperature steam for a standalone, efficient solar autoclave useful for sanitation of instruments or materials in resource-limited, remote locations. Sterilization was verified using a standard Geobacillus stearothermophilus-based biological indicator. PMID:23836642

  19. Building-Integrated Solar Energy Devices based on Wavelength Selective Films

    NASA Astrophysics Data System (ADS)

    Ulavi, Tejas

    A potentially attractive option for building integrated solar is to employ hybrid solar collectors which serve dual purposes, combining solar thermal technology with either thin film photovoltaics or daylighting. In this study, two hybrid concepts, a hybrid photovoltaic/thermal (PV/T) collector and a hybrid 'solar window', are presented and analyzed to evaluate technical performance. In both concepts, a wavelength selective film is coupled with a compound parabolic concentrator (CPC) to reflect and concentrate the infrared portion of the solar spectrum onto a tubular absorber. The visible portion of the spectrum is transmitted through the concentrator to either a thin film Cadmium Telluride (CdTe) solar panel for electricity generation or into the interior space for daylighting. Special attention is given to the design of the hybrid devices for aesthetic building integration. An adaptive concentrator design based on asymmetrical truncation of CPCs is presented for the hybrid solar window concept. The energetic and spectral split between the solar thermal module and the PV or daylighting module are functions of the optical properties of the wavelength selective film and the concentrator geometry, and are determined using a Monte Carlo Ray-Tracing (MCRT) model. Results obtained from the MCRT can be used in conjugation with meteorological data for specific applications to study the impact of CPC design parameters including the half-acceptance angle thetac, absorber diameter D and truncation on the annual thermal and PV/daylighting efficiencies. The hybrid PV/T system is analyzed for a rooftop application in Phoenix, AZ. Compared to a system of the same area with independent solar thermal and PV modules, the hybrid PV/T provides 20% more energy, annually. However, the increase in total delivered energy is due solely to the addition of the thermal module and is achieved at an expense of a decrease in the annual electrical efficiency from 8.8% to 5.8% due to shading by

  20. Refraction-Assisted Solar Thermoelectric Generator based on Phase-Change Lens

    PubMed Central

    Kim, Myoung-Soo; Kim, Min-Ki; Jo, Sung-Eun; Joo, Chulmin; Kim, Yong-Jun

    2016-01-01

    Solar thermoelectric generators (STEGs), which are used for various applications, (particularly small size electronic devices), have optical concentration systems for high energy conversion efficiency. In this study, a refraction-assisted STEG (R-STEG) is designed based on phase-change materials. As the phase-change material (PCM) changes phase from solid to liquid, its refractive index and transmittance also change, resulting in changes in the refraction of the sunlight transmitted through it, and concentration of solar energy in the phase-change lens. This innovative design facilitates double focusing the solar energy through the optical lens and a phase-change lens. This mechanism resulted in the peak energy conversion efficiencies of the R-STEG being 60% and 86% higher than those of the typical STEG at solar intensities of 1 kW m−2 and 1.5 kW m−2, respectively. In addition, the energy stored in PCM can help to generate steady electrical energy when the solar energy was removed. This work presents significant progress regarding the optical characteristic of PCM and optical concentration systems of STEGs. PMID:27283350

  1. Point-Focus Concentration Compact Telescoping Array: Extreme Environments Solar Power Base Phase Final Report

    NASA Technical Reports Server (NTRS)

    McEachen, Michael E.; Murphy, Dave; Meinhold, Shen; Spink, Jim; Eskenazi, Mike; O'Neill, Mark

    2017-01-01

    Orbital ATK, in partnership with Mark ONeill LLC (MOLLC), has developed a novel solar array platform, PFC-CTA, which provides a significant advance in performance and cost reduction compared to all currently available space solar systems. PFC refers to the Point Focus Concentration of light provided by MOLLCs thin, flat Fresnel optics. These lenses focus light to a point of approximately 100 times the intensity of the ambient light, onto a solar cell of approximately 125th the size of the lens. CTA stands for Compact Telescoping Array, which is the solar array blanket structural platform originally devised by NASA and currently being advanced by Orbital ATK and partners under NASA and AFRL funding to a projected TRL 5+ by late-2018.The NASA Game Changing Development Extreme Environment Solar Power (EESP) Base Phase study has enabled Orbital ATK to refine component designs, perform component level and system performance analyses, and test prototype hardware of the key elements of PFC-CTA, and increased the TRL of PFC-specific technology elements to TRL 4. Key performance metrics currently projected are as follows: Scalability from 5 kW to 300 kW per wing (AM0); Specific Power 500 Wkg (AM0); Stowage Efficiency 100 kWm3; 5:1 margin on pointing tolerance vs. capability; 50 launched cost savings; Wide range of operability between Venus and Saturn by active andor passive thermal management.

  2. SolarTherm: A flexible Modelica-based simulator for CSP systems

    NASA Astrophysics Data System (ADS)

    Scott, Paul; Alonso, Alberto de la Calle; Hinkley, James T.; Pye, John

    2017-06-01

    Annual performance simulations provide a valuable tool for analysing the viability and overall impact of different concentrating solar power (CSP) component and system designs. However, existing tools work best with conventional systems and are difficult or impossible to adapt when novel components, configurations and operating strategies are of interest. SolarTherm is a new open source simulation tool that fulfils this need for the solar community. It includes a simulation framework and a library of flexible CSP components and control strategies that can be adapted or replaced with new designs to meet the special needs of end users. This paper provides an introduction to SolarTherm and a comparison of models for an energy-based trough system and a physical tower system to those in the well-established and widely-used simulator SAM. Differences were found in some components where the inner workings of SAM are undocumented or not well understood, while the other parts show strong agreement. These results help to validate the fundamentals of SolarTherm and demonstrate that, while at an early stage of development, it is already a useful tool for performing annual simulations.

  3. EPDM Based Double Slope Triangular Enclosure Solar Collector: A Novel Approach

    PubMed Central

    Qureshi, Shafiq R.; Khan, Waqar A.

    2014-01-01

    Solar heating is one of the important utilities of solar energy both in domestic and industrial sectors. Evacuated tube heaters are a commonly used technology for domestic water heating. However, increasing cost of copper and nickel has resulted in huge initial cost for these types of heaters. Utilizing solar energy more economically for domestic use requires new concept which has low initial and operating costs together with ease of maintainability. As domestic heating requires only nominal heating temperature to the range of 60–90°C, therefore replacing nickel coated copper pipes with any cheap alternate can drastically reduce the cost of solar heater. We have proposed a new concept which utilizes double slope triangular chamber with EPDM based synthetic rubber pipes. This has reduced the initial and operating costs substantially. A detailed analytical study was carried out to design a novel solar heater. On the basis of analytical design, a prototype was manufactured. Results obtained from the experiments were found to be in good agreement with the analytical study. A maximum error of 10% was recorded at noon. However, results show that error is less than 5% in early and late hours. PMID:24688407

  4. EPDM based double slope triangular enclosure solar collector: a novel approach.

    PubMed

    Qureshi, Shafiq R; Khan, Waqar A; Sarwar, Waqas

    2014-01-01

    Solar heating is one of the important utilities of solar energy both in domestic and industrial sectors. Evacuated tube heaters are a commonly used technology for domestic water heating. However, increasing cost of copper and nickel has resulted in huge initial cost for these types of heaters. Utilizing solar energy more economically for domestic use requires new concept which has low initial and operating costs together with ease of maintainability. As domestic heating requires only nominal heating temperature to the range of 60-90 °C, therefore replacing nickel coated copper pipes with any cheap alternate can drastically reduce the cost of solar heater. We have proposed a new concept which utilizes double slope triangular chamber with EPDM based synthetic rubber pipes. This has reduced the initial and operating costs substantially. A detailed analytical study was carried out to design a novel solar heater. On the basis of analytical design, a prototype was manufactured. Results obtained from the experiments were found to be in good agreement with the analytical study. A maximum error of 10% was recorded at noon. However, results show that error is less than 5% in early and late hours.

  5. Reliability analysis of the solar array based on Fault Tree Analysis

    NASA Astrophysics Data System (ADS)

    Jianing, Wu; Shaoze, Yan

    2011-07-01

    The solar array is an important device used in the spacecraft, which influences the quality of in-orbit operation of the spacecraft and even the launches. This paper analyzes the reliability of the mechanical system and certifies the most vital subsystem of the solar array. The fault tree analysis (FTA) model is established according to the operating process of the mechanical system based on DFH-3 satellite; the logical expression of the top event is obtained by Boolean algebra and the reliability of the solar array is calculated. The conclusion shows that the hinges are the most vital links between the solar arrays. By analyzing the structure importance(SI) of the hinge's FTA model, some fatal causes, including faults of the seal, insufficient torque of the locking spring, temperature in space, and friction force, can be identified. Damage is the initial stage of the fault, so limiting damage is significant to prevent faults. Furthermore, recommendations for improving reliability associated with damage limitation are discussed, which can be used for the redesigning of the solar array and the reliability growth planning.

  6. Refraction-Assisted Solar Thermoelectric Generator based on Phase-Change Lens.

    PubMed

    Kim, Myoung-Soo; Kim, Min-Ki; Jo, Sung-Eun; Joo, Chulmin; Kim, Yong-Jun

    2016-06-10

    Solar thermoelectric generators (STEGs), which are used for various applications, (particularly small size electronic devices), have optical concentration systems for high energy conversion efficiency. In this study, a refraction-assisted STEG (R-STEG) is designed based on phase-change materials. As the phase-change material (PCM) changes phase from solid to liquid, its refractive index and transmittance also change, resulting in changes in the refraction of the sunlight transmitted through it, and concentration of solar energy in the phase-change lens. This innovative design facilitates double focusing the solar energy through the optical lens and a phase-change lens. This mechanism resulted in the peak energy conversion efficiencies of the R-STEG being 60% and 86% higher than those of the typical STEG at solar intensities of 1 kW m(-2) and 1.5 kW m(-2), respectively. In addition, the energy stored in PCM can help to generate steady electrical energy when the solar energy was removed. This work presents significant progress regarding the optical characteristic of PCM and optical concentration systems of STEGs.

  7. 25th anniversary article: Rise to power--OPV-based solar parks.

    PubMed

    Krebs, Frederik C; Espinosa, Nieves; Hösel, Markus; Søndergaard, Roar R; Jørgensen, Mikkel

    2014-01-08

    A solar park based on polymer solar cells is described and analyzed with respect to performance, practicality, installation speed, and energy payback time. It is found that a high voltage installation where solar cells are all printed in series enables an installation rate in Watts installed per minute that far exceed any other PV technology in existence. The energy payback time for the practical installation of polymer solar cell foil on a wooden 250 square meter platform in its present form is 277 days when operated in Denmark and 180 days when operated in southern Spain. The installation and de-installation rate is above 100 m min⁻¹, which, with the present performance and web width, implies installation of >200 W min⁻¹. In comparison, this also exceeds the overall manufacturing speed of the polymer solar cell foil with a width of 305 mm which is currently 1 m min⁻¹ for complete encapsulated and tested foil. It is also significant that simultaneous installation and de-installation which enables efficient schemes for decommissioning and recycling is possible. It is highlighted where research efforts should most rationally be invested in order to make grid electricity from OPV a reality (and it is within reach).

  8. Balancing autonomy and utilization of solar power and battery storage for demand based microgrids

    NASA Astrophysics Data System (ADS)

    Lawder, Matthew T.; Viswanathan, Vilayanur; Subramanian, Venkat R.

    2015-04-01

    The growth of intermittent solar power has developed a need for energy storage systems in order to decouple generation and supply of energy. Microgrid (MG) systems comprising of solar arrays with battery energy storage studied in this paper desire high levels of autonomy, seeking to meet desired demand at all times. Large energy storage capacity is required for high levels of autonomy, but much of this expensive capacity goes unused for a majority of the year due to seasonal fluctuations of solar generation. In this paper, a model-based study of MGs comprised of solar generation and battery storage shows the relationship between system autonomy and battery utilization applied to multiple demand cases using a single particle battery model (SPM). The SPM allows for more accurate state-of-charge and utilization estimation of the battery than previous studies of renewably powered systems that have used empirical models. The increased accuracy of battery state estimation produces a better assessment of system performance. Battery utilization will depend on the amount of variation in solar insolation as well as the type of demand required by the MG. Consumers must balance autonomy and desired battery utilization of a system within the needs of their grid.

  9. Performance of conversion efficiency of a crystalline silicon solar cell with base doping density

    NASA Astrophysics Data System (ADS)

    Sahin, Gokhan; Kerimli, Genber; Barro, Fabe Idrissa; Sane, Moustapha; Alma, Mehmet Hakkı

    In this study, we investigate theoretically the electrical parameters of a crystalline silicon solar cell in steady state. Based on a one-dimensional modeling of the cell, the short circuit current density, the open circuit voltage, the shunt and series resistances and the conversion efficiency are calculated, taking into account the base doping density. Either the I-V characteristic, series resistance, shunt resistance and conversion efficiency are determined and studied versus base doping density. The effects applied of base doping density on these parameters have been studied. The aim of this work is to show how short circuit current density, open circuit voltage and parasitic resistances are related to the base doping density and to exhibit the role played by those parasitic resistances on the conversion efficiency of the crystalline silicon solar.

  10. Analysis of Solar Potential of Roofs Based on Digital Terrain Model

    NASA Astrophysics Data System (ADS)

    Gorički, M.; Poslončec-Petrić, V.; Frangeš, S.; Bačić, Ž.

    2017-09-01

    One of the basic goals of the smart city concept is to create a high-quality environment that is long sustainable and economically justifiable. The priority and concrete goal today is to promote and provide sustainable sources of energy (SSE). Croatia is rich with sun energy and as one of the sunniest European countries, it has a huge insufficiently used solar potential at its disposal. The paper describes the procedure of analysing the solar potential of a pilot area Sveti Križ Začretje by means of digital surface model (DSM) and based on the data available in the Meteorological and Hydrological Service of the Republic of Croatia. Although a more detailed analysis would require some additional factors, it is clear that the installation of 19,6m2 of solar panels in each household could cover annual requirements of the household in the analysed area, the locality Sveti Križ Začretje.

  11. A Compressed Sensing-based Image Reconstruction Algorithm for Solar Flare X-Ray Observations

    NASA Astrophysics Data System (ADS)

    Felix, Simon; Bolzern, Roman; Battaglia, Marina

    2017-11-01

    One way of imaging X-ray emission from solar flares is to measure Fourier components of the spatial X-ray source distribution. We present a new compressed sensing-based algorithm named VIS_CS, which reconstructs the spatial distribution from such Fourier components. We demonstrate the application of the algorithm on synthetic and observed solar flare X-ray data from the Reuven Ramaty High Energy Solar Spectroscopic Imager satellite and compare its performance with existing algorithms. VIS_CS produces competitive results with accurate photometry and morphology, without requiring any algorithm- and X-ray-source-specific parameter tuning. Its robustness and performance make this algorithm ideally suited for the generation of quicklook images or large image cubes without user intervention, such as for imaging spectroscopy analysis.

  12. A Compressed Sensing-based Image Reconstruction Algorithm for Solar Flare X-Ray Observations

    SciTech Connect

    Felix, Simon; Bolzern, Roman; Battaglia, Marina, E-mail: simon.felix@fhnw.ch, E-mail: roman.bolzern@fhnw.ch, E-mail: marina.battaglia@fhnw.ch

    One way of imaging X-ray emission from solar flares is to measure Fourier components of the spatial X-ray source distribution. We present a new compressed sensing-based algorithm named VIS-CS, which reconstructs the spatial distribution from such Fourier components. We demonstrate the application of the algorithm on synthetic and observed solar flare X-ray data from the Reuven Ramaty High Energy Solar Spectroscopic Imager satellite and compare its performance with existing algorithms. VIS-CS produces competitive results with accurate photometry and morphology, without requiring any algorithm- and X-ray-source-specific parameter tuning. Its robustness and performance make this algorithm ideally suited for the generation ofmore » quicklook images or large image cubes without user intervention, such as for imaging spectroscopy analysis.« less

  13. Analysis of ionospheric irregularities during total solar eclipse 2016 based on GNSS observation

    NASA Astrophysics Data System (ADS)

    Husin, A.; Jiyo; Anggarani, S.; Ekawati, S.; Dear, V.

    2016-11-01

    A total solar eclipse occurred over Indonesia in the morning hours on 9 March 2016. Ionisations in the ionosphere which is associated with the solar radiation during the total eclipse provided a good opportunity to study the ionospheric irregularities. Using global navigation satellite system (GNSS) data taken from dual-frequency receivers in Manado, we investigated and analysed the total electron content (TEC) perturbations with a time resolution of 60 s to reveal ionospheric irregularities during total eclipse. Result showed that TEC conditions based on IPP were decreased during solar eclipse on March 9, comparing with the neighbour day. The maximum percentage deviation (DTEC) from the average value during eclipse period, 00:00 - 02:40 UT reach -41.5%. The duration of maximum decrement in TEC occurs were around 2-30 minutes after the maximum obscuration.

  14. Recent progress in Si thin film technology for solar cells

    NASA Astrophysics Data System (ADS)

    Kuwano, Yukinori; Nakano, Shoichi; Tsuda, Shinya

    1991-11-01

    Progress in Si thin film technology 'specifically amorphous Si (a-Si) and polycrystalline Si (poly-Si) thin film' for solar cells is summarized here from fabrication method, material, and structural viewpoints. In addition to a-Si, primary results on poly-Si thin film research are discussed. Various applications for a-Si solar cells are mentioned, and consumer applications and a-Si solar cell photovoltaic systems are introduced. New product developments include see-through solar cells, solar cell roofing tiles, and ultra-light flexible solar cells. As for new systems, air conditioning equipment powered by solar cells is described. Looking to the future, the proposed GENESIS project is discussed.

  15. Climate responses to SATIRE and SIM-based spectral solar forcing in a 3D atmosphere-ocean coupled GCM

    NASA Astrophysics Data System (ADS)

    Wen, Guoyong; Cahalan, Robert F.; Rind, David; Jonas, Jeffrey; Pilewskie, Peter; Wu, Dong L.; Krivova, Natalie A.

    2017-03-01

    We apply two reconstructed spectral solar forcing scenarios, one SIM (Spectral Irradiance Monitor) based, the other the SATIRE (Spectral And Total Irradiance REconstruction) modeled, as inputs to the GISS (Goddard Institute for Space Studies) GCMAM (Global Climate Middle Atmosphere Model) to examine climate responses on decadal to centennial time scales, focusing on quantifying the difference of climate response between the two solar forcing scenarios. We run the GCMAM for about 400 years with present day trace gas and aerosol for the two solar forcing inputs. We find that the SIM-based solar forcing induces much larger long-term response and 11-year variation in global averaged stratospheric temperature and column ozone. We find significant decreasing trends of planetary albedo for both forcing scenarios in the 400-year model runs. However the mechanisms for the decrease are very different. For SATIRE solar forcing, the decreasing trend of planetary albedo is associated with changes in cloud cover. For SIM-based solar forcing, without significant change in cloud cover on centennial and longer time scales, the apparent decreasing trend of planetary albedo is mainly due to out-of-phase variation in shortwave radiative forcing proxy (downwelling flux for wavelength >330 nm) and total solar irradiance (TSI). From the Maunder Minimum to present, global averaged annual mean surface air temperature has a response of 0.1 °C to SATIRE solar forcing compared to 0.04 °C to SIM-based solar forcing. For 11-year solar cycle, the global surface air temperature response has 3-year lagged response to either forcing scenario. The global surface air 11-year temperature response to SATIRE forcing is about 0.12 °C, similar to recent multi-model estimates, and comparable to the observational-based evidence. However, the global surface air temperature response to 11-year SIM-based solar forcing is insignificant and inconsistent with observation-based evidence.

  16. A Feasibility Study of CO2-Based Rankine Cycle Powered by Solar Energy

    NASA Astrophysics Data System (ADS)

    Zhang, Xin-Rong; Yamaguchi, Hiroshi; Fujima, Katsumi; Enomoto, Masatoshi; Sawada, Noboru

    An experiment study was carried out in order to investigate feasibility of CO2-based Rankine cycle powered by solar energy. The proposed cycle is to achieve a cogeneration of heat and power, which consists of evacuated solar tube collectors, power generating turbine, heat recovery system, and feed pump. The Rankine cycle of the system utilizes solar collectors to convert CO2 into high-temperature supercritical state, used to drive a turbine and produce electrical power. The cycle also recovers thermal energy, which can be used for absorption refrigerator, air conditioning, hot water supply so on for a building. A set of experimental set-up was constructed to investigate the performance of the CO2-based Rankine cycle. The results show the cycle can achieve production of heat and power with reasonable thermodynamics efficiency and has a great potential of the application of the CO2-based Rankine cycle powered by solar energy. In addition, some research interests related to the present study will also be discussed in this paper.

  17. Use of ground-based telescopes in determining the composition of the surfaces of solar system objects

    NASA Technical Reports Server (NTRS)

    Mccord, T. B.; Adams, J. B.

    1977-01-01

    Recent evidence suggests that the way that the surfaces of the solar system objects reflect solar radiation is controlled by the composition and mineralogy of the surface materials. The way sunlight is reflected from the surface as a function of wavelength, i.e., the spectral reflectance, is the most important property. Laboratory efforts to use ground-based optical telescope measurements to determine the composition of the surfaces of the solar system objects are reviewed.

  18. Efficient Lead-Free Solar Cells Based on Hollow {en}MASnI3 Perovskites.

    PubMed

    Ke, Weijun; Stoumpos, Constantinos C; Spanopoulos, Ioannis; Mao, Lingling; Chen, Michelle; Wasielewski, Michael R; Kanatzidis, Mercouri G

    2017-10-18

    Tin-based perovskites have very comparable electronic properties to lead-based perovskites and are regarded as possible lower toxicity alternates for solar cell applications. However, the efficiency of tin-based perovskite solar cells is still low and they exhibit poor air stability. Here, we report lead-free tin-based solar cells with greatly enhanced performance and stability using so-called "hollow" ethylenediammonium and methylammonium tin iodide ({en}MASnI 3 ) perovskite as absorbers. Our results show that en can improve the film morphology and most importantly can serve as a new cation to be incorporated into the 3D MASnI 3 lattice. When the cation of en becomes part of the 3D structure, a high density of SnI 2 vacancies is created resulting in larger band gap, larger unit cell volume, lower trap-state density, and much longer carrier lifetime compared to classical MASnI 3 . The best-performing {en}MASnI 3 solar cell has achieved a high efficiency of 6.63% with an open circuit voltage of 428.67 mV, a short-circuit current density of 24.28 mA cm -2 , and a fill factor of 63.72%. Moreover, the {en}MASnI 3 device shows much better air stability than the neat MASnI 3 device. Comparable performance is also achieved for cesium tin iodide solar cells with en loading, demonstrating the broad scope of this approach.

  19. Photovoltaic reciprocity and quasi-Fermi level splitting in nanostructure-based solar cells (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Aeberhard, Urs

    2017-04-01

    The photovoltaic reciprocity theory relates the electroluminescence spectrum of a solar cell under applied bias to the external photovoltaic quantum efficiency of the device as measured at short circuit conditions [1]. So far, the theory has been verified for a wide range of devices and material systems and forms the basis of a growing number of luminesecence imaging techniques used in the characterization of photovoltaic materials, cells and modules [2-5]. However, there are also some examples where the theory fails, such as in the case of amorphous silicon. In our contribution, we critically assess the assumptions made in the derivation of the theory and compare its predictions with rigorous formal relations as well as numerical computations in the framework of a comprehensive quantum-kinetic theory of photovoltaics [6] as applied to ultra-thin absorber architectures [7]. One of the main applications of the photovoltaic reciprocity relation is the determination of quasi-Fermi level splittings (QFLS) in solar cells from the measurement of luminescence. In nanostructure-based photovoltaic architectures, the determination of QFLS is challenging, but instrumental to assess the performance potential of the concepts. Here, we use our quasi-Fermi level-free theory to investigate existence and size of QFLS in quantum well and quantum dot solar cells. [1] Uwe Rau. Reciprocity relation between photovoltaic quantum efficiency and electrolumines- cent emission of solar cells. Phys. Rev. B, 76(8):085303, 2007. [2] Thomas Kirchartz and Uwe Rau. Electroluminescence analysis of high efficiency cu(in,ga)se2 solar cells. J. Appl. Phys., 102(10), 2007. [3] Thomas Kirchartz, Uwe Rau, Martin Hermle, Andreas W. Bett, Anke Helbig, and Jrgen H. Werner. Internal voltages in GaInP-GaInAs-Ge multijunction solar cells determined by electro- luminescence measurements. Appl. Phys. Lett., 92(12), 2008. [4] Thomas Kirchartz, Anke Helbig, Wilfried Reetz, Michael Reuter, Jürgen H. Werner, and

  20. Quantum Dot Sensitized Solar Cells Based on TiO2/AgInS2

    NASA Astrophysics Data System (ADS)

    Pawar, Sachin A.; Jeong, Jae Pil; Patil, Dipali S.; More, Vivek M.; Lee, Rochelle S.; Shin, Jae Cheol; Choi, Won Jun

    2018-05-01

    Quantum dot heterojunctions with type-II band alignment can efficiently separate photogenerated electron-hole pairs and, hence, are useful for solar cell studies. In this study, a quantum dot sensitized solar cell (QDSSC) made of TiO2/AgInS2 is achieved to boost the photoconversion efficiency for the TiO2-based system by varying the AgInS2 layer's thickness. The TiO2 nanorods array film is prepared by using a simple hydrothermal technique. The formation of a AgInS2 QD-sensitized TiO2-nanorod photoelectrode is carried out by successive ionic layer adsorption and reaction (SILAR) technique. The effect of the QD layer on the performance of the solar cell is studied by varying the SILAR cycles of the QD coating. The synthesized electrode materials are characterized by using X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy and solar cell performances. The results indicate that the nanocrystals have effectively covered the outer surfaces of the TiO2 nanorods. The interfacial structure of quantum dots (QDs)/TiO2 is also investigated, and the growth interface is verified. A careful comparison between TiO2/AgInS2 sensitized cells reveals that the trasfer of electrons and hole proceeds efficiently, the recombination is suppressed for the optimum thickness of the QD layer and light from the entire visible spectrum is utilised. Under AM 1.5G illumination, a high photocurrent of 1.36 mAcm-2 with an improved power conversion efficiency of 0.48% is obtained. The solar cell properties of our photoanodes suggest that the TiO2 nanorod array films co-sensitized by AgInS2 nanoclusters have potential applications in solar cells.

  1. Forecast and Specification of Radiation Belt Electrons Based on Solar Wind Measurements

    NASA Astrophysics Data System (ADS)

    Li, X.; Barker, A.; Burin Des Roziers, E.

    2003-12-01

    Relativistic electrons in the Earth's magnetosphere are of considerable practical importance because of their effect on spacecraft and because of their radiation hazard to astronauts who perform extravehicular activity. The good correlation between solar wind velocity and MeV electron fluxes at geosynchronous orbit has long been established. We have developed a radial diffusion model, using solar wind parameters as the only input, to reproduce the variation of the MeV electrons at geosynchronous orbit. Based on this model, we have constructed a real-time model that forecasts one to two days in advance the daily averaged >2 MeV electron flux at geosynchronous orbit using real-time solar wind data from ACE. The forecasts from this model are available on the web in real time. A natural extension of our current model is to create a system for making quantitative forecasts and specifications of radiation belt electrons at different radial distances and different local times based on the solar wind conditions. The successes and obstacles associated with this extension will be discussed in this presentation.

  2. One-dimension-based spatially ordered architectures for solar energy conversion.

    PubMed

    Liu, Siqi; Tang, Zi-Rong; Sun, Yugang; Colmenares, Juan Carlos; Xu, Yi-Jun

    2015-08-07

    The severe consequences of fossil fuel consumption have resulted in a need for alternative sustainable sources of energy. Conversion and storage of solar energy via a renewable method, such as photocatalysis, holds great promise as such an alternative. One-dimensional (1D) nanostructures have gained attention in solar energy conversion because they have a long axis to absorb incident sunlight yet a short radial distance for separation of photogenerated charge carriers. In particular, well-ordered spatially high dimensional architectures based on 1D nanostructures with well-defined facets or anisotropic shapes offer an exciting opportunity for bridging the gap between 1D nanostructures and the micro and macro world, providing a platform for integration of nanostructures on a larger and more manageable scale into high-performance solar energy conversion applications. In this review, we focus on the progress of photocatalytic solar energy conversion over controlled one-dimension-based spatially ordered architecture hybrids. Assembly and classification of these novel architectures are summarized, and we discuss the opportunity and future direction of integration of 1D materials into high-dimensional, spatially organized architectures, with a perspective toward improved collective performance in various artificial photoredox applications.

  3. Temperature-based estimation of global solar radiation using soft computing methodologies

    NASA Astrophysics Data System (ADS)

    Mohammadi, Kasra; Shamshirband, Shahaboddin; Danesh, Amir Seyed; Abdullah, Mohd Shahidan; Zamani, Mazdak

    2016-07-01

    Precise knowledge of solar radiation is indeed essential in different technological and scientific applications of solar energy. Temperature-based estimation of global solar radiation would be appealing owing to broad availability of measured air temperatures. In this study, the potentials of soft computing techniques are evaluated to estimate daily horizontal global solar radiation (DHGSR) from measured maximum, minimum, and average air temperatures ( T max, T min, and T avg) in an Iranian city. For this purpose, a comparative evaluation between three methodologies of adaptive neuro-fuzzy inference system (ANFIS), radial basis function support vector regression (SVR-rbf), and polynomial basis function support vector regression (SVR-poly) is performed. Five combinations of T max, T min, and T avg are served as inputs to develop ANFIS, SVR-rbf, and SVR-poly models. The attained results show that all ANFIS, SVR-rbf, and SVR-poly models provide favorable accuracy. Based upon all techniques, the higher accuracies are achieved by models (5) using T max- T min and T max as inputs. According to the statistical results, SVR-rbf outperforms SVR-poly and ANFIS. For SVR-rbf (5), the mean absolute bias error, root mean square error, and correlation coefficient are 1.1931 MJ/m2, 2.0716 MJ/m2, and 0.9380, respectively. The survey results approve that SVR-rbf can be used efficiently to estimate DHGSR from air temperatures.

  4. Effect of Grain Boundaries on the Performance of Thin-Film-Based Polycrystalline Silicon Solar Cells: A Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Chhetri, Nikita; Chatterjee, Somenath

    2018-01-01

    Solar cells/photovoltaic, a renewable energy source, is appraised to be the most effective alternative to the conventional electrical energy generator. A cost-effective alternative of crystalline wafer-based solar cell is thin-film polycrystalline-based solar cell. This paper reports the numerical analysis of dependency of the solar cell parameters (i.e., efficiency, fill factor, open-circuit voltage and short-circuit current density) on grain size for thin-film-based polycrystalline silicon (Si) solar cells. A minority carrier lifetime model is proposed to do a correlation between the grains, grain boundaries and lifetime for thin-film-based polycrystalline Si solar cells in MATLAB environment. As observed, the increment in the grain size diameter results in increase in minority carrier lifetime in polycrystalline Si thin film. A non-equivalent series resistance double-diode model is used to find the dark as well as light (AM1.5) current-voltage (I-V) characteristics for thin-film-based polycrystalline Si solar cells. To optimize the effectiveness of the proposed model, a successive approximation method is used and the corresponding fitting parameters are obtained. The model is validated with the experimentally obtained results reported elsewhere. The experimentally reported solar cell parameters can be found using the proposed model described here.

  5. Graphene-Based Photocatalysts for CO2 Reduction to Solar Fuel.

    PubMed

    Low, Jingxiang; Yu, Jiaguo; Ho, Wingkei

    2015-11-05

    Recently, photocatalytic CO2 reduction for solar fuel production has attracted much attention because of its potential for simultaneously solving energy and global warming problems. Many studies have been conducted to prepare novel and efficient photocatalysts for CO2 reduction. Graphene, a two-dimensional material, has been increasingly used in photocatalytic CO2 reduction. In theory, graphene shows several remarkable properties, including excellent electronic conductivity, good optical transmittance, large specific surface area, and superior chemical stability. Attributing to these advantages, fabrication of graphene-based materials has been known as one of the most feasible strategies to improve the CO2 reduction performance of photocatalysts. This Perspective mainly focuses on the recent important advances in the fabrication and application of graphene-based photocatalysts for CO2 reduction to solar fuels. The existing challenges and difficulties of graphene-based photocatalysts are also discussed for future application.

  6. Thin-film filament-based solar cells and modules

    NASA Astrophysics Data System (ADS)

    Tuttle, J. R.; Cole, E. D.; Berens, T. A.; Alleman, J.; Keane, J.

    1997-04-01

    This concept paper describes a patented, novel photovoltaic (PV) technology that is capable of achieving near-term commercialization and profitability based upon design features that maximize product performance while minimizing initial and future manufacturing costs. DayStar Technologies plans to exploit these features and introduce a product to the market based upon these differential positions. The technology combines the demonstrated performance and reliability of existing thin-film PV product with a cell and module geometry that cuts material usage by a factor of 5, and enhances performance and manufacturability relative to standard flat-plate designs. The target product introduction price is 1.50/Watt-peak (Wp). This is approximately one-half the cost of the presently available PV product. Additional features include: increased efficiency through low-level concentration, no scribe or grid loss, simple series interconnect, high voltage, light weight, high-throughput manufacturing, large area immediate demonstration, flexibility, modularity.

  7. 78 FR 61999 - Simon Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-10

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-2490-000] Simon Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding, of Simon Solar...

  8. 76 FR 3624 - 3C Solar LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-20

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-2649-000] 3C Solar LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization January 12, 2011. This is a supplemental notice in the above-referenced proceeding 3C Solar LLC's...

  9. 78 FR 49508 - Solar Partners I, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-14

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-2107-000] Solar Partners I, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding of Solar...

  10. 76 FR 40722 - Mojave Solar LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-11

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-3917-000] Mojave Solar LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding of Mojave Solar LLC...

  11. 78 FR 29130 - Solar Star California XIX, LLC; Supplemental Notice that Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-17

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-1441-000] Solar Star California XIX, LLC; Supplemental Notice that Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding, of Solar Star...

  12. 77 FR 64979 - BITH Solar 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-24

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-29-000] BITH Solar 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding of BITH Solar 1...

  13. 77 FR 26538 - Topaz Solar Farms LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-04

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-1626-000] Topaz Solar Farms LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding of Topaz Solar...

  14. 78 FR 29131 - Solar Star California XX, LLC; Supplemental Notice that Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-17

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-1442-000] Solar Star California XX, LLC; Supplemental Notice that Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding, of Solar Star...

  15. 78 FR 49507 - Genesis Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-14

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-2112-000] Genesis Solar, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding of Genesis Solar...

  16. 77 FR 41400 - AV Solar Ranch 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-13

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-2178-000] AV Solar Ranch 1, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding of AV Solar...

  17. 77 FR 48148 - NRG Solar Borrego I LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-13

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-2398-000] NRG Solar Borrego I LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding, of NRG Solar...

  18. 77 FR 37666 - NRG Solar Avra Valley LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-22

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-2019-000] NRG Solar Avra Valley LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding of NRG Solar...

  19. Space-based solar power conversion and delivery systems study. Volume 2: Engineering analysis of orbital systems

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Program plans, schedules, and costs are determined for a synchronous orbit-based power generation and relay system. Requirements for the satellite solar power station (SSPS) and the power relay satellite (PRS) are explored. Engineering analysis of large solar arrays, flight mechanics and control, transportation, assembly and maintenance, and microwave transmission are included.

  20. Solar Technologies

    ERIC Educational Resources Information Center

    von Hippel, Frank; Williams, Robert H.

    1975-01-01

    As fossil fuels decrease in availability and environmental concerns increase, soalr energy is becoming a potential major energy source. Already solar energy is used for space heating in homes. Proposals for solar-electric generating systems include land-based or ocean-based collectors and harnessing wind and wave power. Photosynthesis can also…

  1. Ruthenium based metallopolymer grafted reduced graphene oxide as a new hybrid solar light harvester in polymer solar cells

    PubMed Central

    Vinoth, R.; Babu, S. Ganesh; Bharti, Vishal; Gupta, V.; Navaneethan, M.; Bhat, S. Venkataprasad; Muthamizhchelvan, C.; Ramamurthy, Praveen C.; Sharma, Chhavi; Aswal, Dinesh K.; Hayakawa, Yasuhiro; Neppolian, B.

    2017-01-01

    A new class of pyridyl benzimdazole based Ru complex decorated polyaniline assembly (PANI-Ru) was covalently grafted onto reduced graphene oxide sheets (rGO) via covalent functionalization approach. The covalent attachment of PANI-Ru with rGO was confirmed from XPS analysis and Raman spectroscopy. The chemical bonding between PANI-Ru and rGO induced the electron transfer from Ru complex to rGO via backbone of the conjugated PANI chain. The resultant hybrid metallopolymer assembly was successfully demonstrated as an electron donor in bulk heterojunction polymer solar cells (PSCs). A PSC device fabricated with rGO/PANI-Ru showed an utmost ~6 fold and 2 fold enhancement in open circuit potential (Voc) and short circuit current density (Jsc) with respect to the standard device made with PANI-Ru (i.e., without rGO) under the illumination of AM 1.5 G. The excellent electronic properties of rGO significantly improved the electron injection from PANI-Ru to PCBM and in turn the overall performance of the PSC device was enhanced. The ultrafast excited state charge separation and electron transfer role of rGO sheet in hybrid metallopolymer was confirmed from ultrafast spectroscopy measurements. This covalent modification of rGO with metallopolymer assembly may open a new strategy for the development of new hybrid nanomaterials for light harvesting applications. PMID:28225039

  2. An XML-based Generic Tool for Information Retrieval in Solar Databases

    NASA Astrophysics Data System (ADS)

    Scholl, Isabelle F.; Legay, Eric; Linsolas, Romain

    This paper presents the current architecture of the `Solar Web Project' now in its development phase. This tool will provide scientists interested in solar data with a single web-based interface for browsing distributed and heterogeneous catalogs of solar observations. The main goal is to have a generic application that can be easily extended to new sets of data or to new missions with a low level of maintenance. It is developed with Java and XML is used as a powerful configuration language. The server, independent of any database scheme, can communicate with a client (the user interface) and several local or remote archive access systems (such as existing web pages, ftp sites or SQL databases). Archive access systems are externally described in XML files. The user interface is also dynamically generated from an XML file containing the window building rules and a simplified database description. This project is developed at MEDOC (Multi-Experiment Data and Operations Centre), located at the Institut d'Astrophysique Spatiale (Orsay, France). Successful tests have been conducted with other solar archive access systems.

  3. Two solar proton fluence models based on ground level enhancement observations

    NASA Astrophysics Data System (ADS)

    Raukunen, Osku; Vainio, Rami; Tylka, Allan J.; Dietrich, William F.; Jiggens, Piers; Heynderickx, Daniel; Dierckxsens, Mark; Crosby, Norma; Ganse, Urs; Siipola, Robert

    2018-01-01

    Solar energetic particles (SEPs) constitute an important component of the radiation environment in interplanetary space. Accurate modeling of SEP events is crucial for the mitigation of radiation hazards in spacecraft design. In this study we present two new statistical models of high energy solar proton fluences based on ground level enhancement (GLE) observations during solar cycles 19-24. As the basis of our modeling, we utilize a four parameter double power law function (known as the Band function) fits to integral GLE fluence spectra in rigidity. In the first model, the integral and differential fluences for protons with energies between 10 MeV and 1 GeV are calculated using the fits, and the distributions of the fluences at certain energies are modeled with an exponentially cut-off power law function. In the second model, we use a more advanced methodology: by investigating the distributions and relationships of the spectral fit parameters we find that they can be modeled as two independent and two dependent variables. Therefore, instead of modeling the fluences separately at different energies, we can model the shape of the fluence spectrum. We present examples of modeling results and show that the two methodologies agree well except for a short mission duration (1 year) at low confidence level. We also show that there is a reasonable agreement between our models and three well-known solar proton models (JPL, ESP and SEPEM), despite the differences in both the modeling methodologies and the data used to construct the models.

  4. A Neural Network Based Intelligent Predictive Sensor for Cloudiness, Solar Radiation and Air Temperature

    PubMed Central

    Ferreira, Pedro M.; Gomes, João M.; Martins, Igor A. C.; Ruano, António E.

    2012-01-01

    Accurate measurements of global solar radiation and atmospheric temperature, as well as the availability of the predictions of their evolution over time, are important for different areas of applications, such as agriculture, renewable energy and energy management, or thermal comfort in buildings. For this reason, an intelligent, light-weight and portable sensor was developed, using artificial neural network models as the time-series predictor mechanisms. These have been identified with the aid of a procedure based on the multi-objective genetic algorithm. As cloudiness is the most significant factor affecting the solar radiation reaching a particular location on the Earth surface, it has great impact on the performance of predictive solar radiation models for that location. This work also represents one step towards the improvement of such models by using ground-to-sky hemispherical colour digital images as a means to estimate cloudiness by the fraction of visible sky corresponding to clouds and to clear sky. The implementation of predictive models in the prototype has been validated and the system is able to function reliably, providing measurements and four-hour forecasts of cloudiness, solar radiation and air temperature. PMID:23202230

  5. Forecasting Solar Flares Using Magnetogram-based Predictors and Machine Learning

    NASA Astrophysics Data System (ADS)

    Florios, Kostas; Kontogiannis, Ioannis; Park, Sung-Hong; Guerra, Jordan A.; Benvenuto, Federico; Bloomfield, D. Shaun; Georgoulis, Manolis K.

    2018-02-01

    We propose a forecasting approach for solar flares based on data from Solar Cycle 24, taken by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) mission. In particular, we use the Space-weather HMI Active Region Patches (SHARP) product that facilitates cut-out magnetograms of solar active regions (AR) in the Sun in near-realtime (NRT), taken over a five-year interval (2012 - 2016). Our approach utilizes a set of thirteen predictors, which are not included in the SHARP metadata, extracted from line-of-sight and vector photospheric magnetograms. We exploit several machine learning (ML) and conventional statistics techniques to predict flares of peak magnitude {>} M1 and {>} C1 within a 24 h forecast window. The ML methods used are multi-layer perceptrons (MLP), support vector machines (SVM), and random forests (RF). We conclude that random forests could be the prediction technique of choice for our sample, with the second-best method being multi-layer perceptrons, subject to an entropy objective function. A Monte Carlo simulation showed that the best-performing method gives accuracy ACC=0.93(0.00), true skill statistic TSS=0.74(0.02), and Heidke skill score HSS=0.49(0.01) for {>} M1 flare prediction with probability threshold 15% and ACC=0.84(0.00), TSS=0.60(0.01), and HSS=0.59(0.01) for {>} C1 flare prediction with probability threshold 35%.

  6. Broadband absorption enhancement in plasmonic nanoshells-based ultrathin microcrystalline-Si solar cells

    NASA Astrophysics Data System (ADS)

    Raja, Waseem; Bozzola, Angelo; Zilio, Pierfrancesco; Miele, Ermanno; Panaro, Simone; Wang, Hai; Toma, Andrea; Alabastri, Alessandro; de Angelis, Francesco; Zaccaria, Remo Proietti

    2016-04-01

    With the objective to conceive a plasmonic solar cell with enhanced photocurrent, we investigate the role of plasmonic nanoshells, embedded within a ultrathin microcrystalline silicon solar cell, in enhancing broadband light trapping capability of the cell and, at the same time, to reduce the parasitic loss. The thickness of the considered microcrystalline silicon (μc-Si) layer is only ~1/6 of conventional μc-Si based solar cells while the plasmonic nanoshells are formed by a combination of silica and gold, respectively core and shell. We analyze the cell optical response by varying both the geometrical and optical parameters of the overall device. In particular, the nanoshells core radius and metal thickness, the periodicity, the incident angle of the solar radiation and its wavelength are varied in the widest meaningful ranges. We further explain the reason for the absorption enhancement by calculating the electric field distribution associated to resonances of the device. We argue that both Fabry-Pérot-like and localized plasmon modes play an important role in this regard.

  7. Petascale Computing for Ground-Based Solar Physics with the DKIST Data Center

    NASA Astrophysics Data System (ADS)

    Berukoff, Steven J.; Hays, Tony; Reardon, Kevin P.; Spiess, DJ; Watson, Fraser; Wiant, Scott

    2016-05-01

    When construction is complete in 2019, the Daniel K. Inouye Solar Telescope will be the most-capable large aperture, high-resolution, multi-instrument solar physics facility in the world. The telescope is designed as a four-meter off-axis Gregorian, with a rotating Coude laboratory designed to simultaneously house and support five first-light imaging and spectropolarimetric instruments. At current design, the facility and its instruments will generate data volumes of 3 PB per year, and produce 107-109 metadata elements.The DKIST Data Center is being designed to store, curate, and process this flood of information, while providing association of science data and metadata to its acquisition and processing provenance. The Data Center will produce quality-controlled calibrated data sets, and make them available freely and openly through modern search interfaces and APIs. Documented software and algorithms will also be made available through community repositories like Github for further collaboration and improvement.We discuss the current design and approach of the DKIST Data Center, describing the development cycle, early technology analysis and prototyping, and the roadmap ahead. We discuss our iterative development approach, the underappreciated challenges of calibrating ground-based solar data, the crucial integration of the Data Center within the larger Operations lifecycle, and how software and hardware support, intelligently deployed, will enable high-caliber solar physics research and community growth for the DKIST's 40-year lifespan.

  8. Design of DSP-based high-power digital solar array simulator

    NASA Astrophysics Data System (ADS)

    Zhang, Yang; Liu, Zhilong; Tong, Weichao; Feng, Jian; Ji, Yibo

    2013-12-01

    To satisfy rigid performance specifications, a feedback control was presented for zoom optical lens plants. With the increasing of global energy consumption, research of the photovoltaic(PV) systems get more and more attention. Research of the digital high-power solar array simulator provides technical support for high-power grid-connected PV systems research.This paper introduces a design scheme of the high-power digital solar array simulator based on TMS320F28335. A DC-DC full-bridge topology was used in the system's main circuit. The switching frequency of IGBT is 25kHz.Maximum output voltage is 900V. Maximum output current is 20A. Simulator can be pre-stored solar panel IV curves.The curve is composed of 128 discrete points .When the system was running, the main circuit voltage and current values was feedback to the DSP by the voltage and current sensors in real-time. Through incremental PI,DSP control the simulator in the closed-loop control system. Experimental data show that Simulator output voltage and current follow a preset solar panels IV curve. In connection with the formation of high-power inverter, the system becomes gridconnected PV system. The inverter can find the simulator's maximum power point and the output power can be stabilized at the maximum power point (MPP).

  9. Carbene based photochemical molecular assemblies for solar driven hydrogen generation.

    PubMed

    Peuntinger, Katrin; Pilz, T David; Staehle, Robert; Schaub, Markus; Kaufhold, Simon; Petermann, Lydia; Wunderlin, Markus; Görls, Helmar; Heinemann, Frank W; Li, Jing; Drewello, Thomas; Vos, Johannes G; Guldi, Dirk M; Rau, Sven

    2014-09-28

    Novel photocatalysts based on ruthenium complexes with NHC (N-heterocyclic carbene)-type bridging ligands have been prepared and structurally and photophysically characterised. The identity of the NHC-unit of the bridging ligand was established unambiguously by means of X-ray structural analysis of a heterodinuclear ruthenium-silver complex. The photophysical data indicate ultrafast intersystem crossing into an emissive and a non-emissive triplet excited state after excitation of the ruthenium centre. Exceptionally high luminescence quantum yields of up to 39% and long lifetimes of up to 2 μs are some of the triplet excited state characteristics. Preliminary studies into the visible light driven photocatalytic hydrogen formation show no induction phase and constant turnover frequencies that are independent on the concentration of the photocatalyst. In conclusion this supports the notion of a stable assembly under photocatalytic conditions.

  10. Low-Pressure Vapor-Assisted Solution Process for Thiocyanate-Based Pseudohalide Perovskite Solar Cells.

    PubMed

    Chiang, Yu-Hsien; Cheng, Hsin-Min; Li, Ming-Hsien; Guo, Tzung-Fang; Chen, Peter

    2016-09-22

    In this report, we fabricated thiocyanate-based perovskite solar cells with low-pressure vapor-assisted solution process (LP-VASP) method. Photovoltaic performances are evaluated with detailed materials characterizations. Scanning electron microscopy images show that SCN-based perovskite films fabricated using LP-VASP have long-range uniform morphology and large grain sizes up to 1 μm. The XRD and Raman spectra were employed to observe the characteristic peaks for both SCN-based and pure CH 3 NH 3 PbI 3 perovskite. We observed that the Pb(SCN) 2 film transformed to PbI 2 before the formation of perovskite film. X-ray photoemission spectra (XPS) show that only a small amount of S remained in the film. Using LP-VASP method, we fabricated SCN-based perovskite solar cells and achieved a power conversion efficiency of 12.72 %. It is worth noting that the price of Pb(SCN) 2 is only 4 % of PbI 2 . These results demonstrate that pseudo-halide perovskites are promising materials for fabricating low-cost perovskite solar cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Research Update: Comparison of salt- and molecular-based iodine treatments of PbS nanocrystal solids for solar cells

    SciTech Connect

    Jähnig, Fabian; Bozyigit, Deniz; Yarema, Olesya

    2015-02-01

    Molecular- and salt-based chemical treatments are believed to passivate electronic trap states in nanocrystal-based semiconductors, which are considered promising for solar cells but suffer from high carrier recombination. Here, we compare the chemical, optical, and electronic properties of PbS nanocrystal-based solids treated with molecular iodine and tetrabutylammonium iodide. Surprisingly, both treatments increase—rather than decrease—the number density of trap states; however, the increase does not directly influence solar cell performance. We explain the origins of the observed impact on solar cell performance and the potential in using different chemical treatments to tune charge carrier dynamics in nanocrystal-solids.

  12. A photodiode based on PbS nanocrystallites for FYTRONIX solar panel automatic tracking controller

    NASA Astrophysics Data System (ADS)

    Wageh, S.; Farooq, W. A.; Tataroğlu, A.; Dere, A.; Al-Sehemi, Abdullah G.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, F.

    2017-12-01

    The structural, optical and photoelectrical properties of the fabricated Al/PbS/p-Si/Al photodiode based on PbS nanocrystallites were investigated. The PbS nanocrystallites were characterized by X-ray diffraction (XRD), UV-VIS-NIR, Infrared and Raman spectroscopy. The XRD diffraction peaks show that the prepared PbS nanostructure is in high crystalline state. Various electrical parameters of the prepared photodiode were analyzed from the electrical characteristics based on I-V and C-V-G. The photodiode has a high rectification ratio of 5.85×104 at dark and ±4 V. Moreover, The photocurrent results indicate a strong photovoltaic behavior. The frequency dependence of capacitance and conductance characteristics was attributed to depletion region behavior of the photodiode. The diode was used to control solar panel power automatic tracking controller in dual axis. The fabricated photodiode works as a photosensor to control Solar tracking systems.

  13. Novel Space-based Solar Power Technologies and Architectures for Earth and Beyond

    NASA Technical Reports Server (NTRS)

    Howell, Joe T.; Fikes, John C.; O'Neill, Mark J.

    2005-01-01

    Research, development and studies of novel space-based solar power systems, technologies and architectures for Earth and beyond are needed to reduce the cost of clean electrical power for terrestrial use and to provide a stepping stone for providing an abundance of power in space, i.e., manufacturing facilities, tourist facilities, delivery of power between objects in space, and between space and surface sites. The architectures, technologies and systems needed for space to Earth applications may also be used for in-space applications. Advances in key technologies, i.e., power generation, power management and distribution, power beaming and conversion of beamed power are needed to achieve the objectives of both terrestrial and extraterrestrial applications. Power beaming or wireless power transmission (WPT) can involve lasers or microwaves along with the associated power interfaces. Microwave and laser transmission techniques have been studied with several promising approaches to safe and efficient WPT identified. These investigations have included microwave phased array transmitters, as well as laser transmission and associated optics. There is a need to produce "proof-of-concept" validation of critical WPT technologies for both the near-term, as well as far-term applications. Investments may be harvested in near-term beam safe demonstrations of commercial WPT applications. Receiving sites (users) include ground-based stations for terrestrial electrical power, orbital sites to provide power for satellites and other platforms, future space elevator systems, space vehicle propulsion, and space to surface sites. This paper briefly discusses achieving a promising approach to the solar power generation and beamed power conversion. The approach is based on a unique high-power solar concentrator array called Stretched Lens Array (SLA) for both solar power generation and beamed power conversion. Since both versions (solar and laser) of SLA use many identical components

  14. Polar low ionospheric responses to the most energetic SPE of the solar cycle#23 based on cosmic noise absorption

    NASA Astrophysics Data System (ADS)

    Pacini, A. A.; Brum, C. G.

    2013-05-01

    We present a detailed study of the impact of solar proton event over the polar low ionosphere, occurred in Jan/2005, during the descendent phase of the XXIII solar activity cycle. This event was the hardest SPE of the last solar cycle, and was associated to a solar X-ray flare X.2 and CME halo. For this study, we are using cosmic noise absorption data measured by a riometer located in Oulu, Finland (65oN) along with solar proton data from GOES satellite. Based on computation simulations we intend to explain the 30MHz riometer absorption events based on variations of the flux and spectrum of the energetic particle precipitated.

  15. Liquid-phase explosive crystallization of electron-beam-evaporated a-Si films induced by flash lamp annealing

    NASA Astrophysics Data System (ADS)

    Ohdaira, Keisuke; Matsumura, Hideki

    2013-01-01

    We succeed in the formation of micrometer-order-thick polycrystalline silicon (poly-Si) films through the flash-lamp-induced liquid-phase explosive crystallization (EC) of precursor a-Si films prepared by electron-beam (EB) evaporation. The velocity of the explosive crystallization (vEC) is estimated to be ˜14 m/s, which is close to the velocity of the liquid-phase epitaxy (LPE) of Si at a temperature around the melting point of a-Si of 1418 K. Poly-Si films formed have micrometer-order-long grains stretched along a lateral crystallization direction, and X-ray diffraction (XRD) and electron diffraction pattern measurements reveal that grains in poly-Si films tend to have a particular orientation. These features are significantly different from our previous results: the formation of poly-Si films containing randomly-oriented 10-nm-sized fine grains formed from a-Si films prepared by catalytic chemical vapor deposition (Cat-CVD) or sputtering. One possible reason for the emergence of a different EC mode in EB-evaporated a-Si films is the suppression of solid-phase nucleation (SPN) during Flash Lamp Annealing (FLA) due to tensile stress which precursor a-Si films originally hold. Poly-Si films formed from EB-evaporated a-Si films would contribute to the realization of high-efficiency thin-film poly-Si solar cells because of large and oriented grains.

  16. Thermodynamic Spectrum of Solar Flares Based on SDO/EVE Observations: Techniques and First Results

    NASA Technical Reports Server (NTRS)

    Wang, Yuming; Zhou, Zhenjun; Zhang, Jie; Liu, Kai; Liu, Rui; Shen, Chenglong; Chamberlin, Phillip C.

    2016-01-01

    The Solar Dynamics Observatory (SDO)/EUV Variability Experiment (EVE) provides rich information on the thermodynamic processes of solar activities, particularly on solar flares. Here, we develop a method to construct thermodynamic spectrum (TDS) charts based on the EVE spectral lines. This tool could potentially be useful for extreme ultraviolet (EUV) astronomy to learn about the eruptive activities on distant astronomical objects. Through several cases, we illustrate what we can learn from the TDS charts. Furthermore, we apply the TDS method to 74 flares equal to or greater than the M5.0 class, and reach the following statistical results. First, EUV peaks are always behind the soft X-ray (SXR) peaks and stronger flares tend to have faster cooling rates. There is a power-law correlation between the peak delay times and the cooling rates, suggesting a coherent cooling process of flares from SXR to EUV emissions. Second, there are two distinct temperature drift patterns, called Type I and Type II. For Type I flares, the enhanced emission drifts from high to low temperature like a quadrilateral, whereas for Type II flares the drift pattern looks like a triangle. Statistical analysis suggests that Type II flares are more impulsive than Type I flares. Third, for late-phase flares, the peak intensity ratio of the late phase to the main phase is roughly correlated with the flare class, and the flares with a strong late phase are all confined. We believe that the re-deposition of the energy carried by a flux rope, which unsuccessfully erupts out, into thermal emissions is responsible for the strong late phase found in a confined flare. Furthermore, we show the signatures of the flare thermodynamic process in the chromosphere and transition region in the TDS charts. These results provide new clues to advance our understanding of the thermodynamic processes of solar flares and associated solar eruptions, e.g., coronal mass ejections.

  17. Fully solution-processed transparent electrodes based on silver nanowire composites for perovskite solar cells.

    PubMed

    Kim, Areum; Lee, Hongseuk; Kwon, Hyeok-Chan; Jung, Hyun Suk; Park, Nam-Gyu; Jeong, Sunho; Moon, Jooho

    2016-03-28

    We report all-solution-processed transparent conductive electrodes based on Ag nanowire (AgNW)-embedded metal oxide composite films for application in organometal halide perovskite solar cells. To address the thermal instability of Ag nanowires, we used combustive sol-gel derived thin films to construct ZnO/ITO/AgNW/ITO composite structures. The resulting composite configuration effectively prevented the AgNWs from undergoing undesirable side-reactions with halogen ions present in the perovskite precursor solutions that significantly deteriorate the optoelectrical properties of Ag nanowires in transparent conductive films. AgNW-based composite electrodes had a transmittance of ∼80% at 550 nm and sheet resistance of 18 Ω sq(-1). Perovskite solar cells fabricated using a fully solution-processed transparent conductive electrode, Au/spiro-OMeTAD/CH3NH3PbI3 + m-Al2O3/ZnO/ITO/AgNW/ITO, exhibited a power conversion efficiency of 8.44% (comparable to that of the FTO/glass-based counterpart at 10.81%) and were stable for 30 days in ambient air. Our results demonstrate the feasibility of using AgNWs as a transparent bottom electrode in perovskite solar cells produced by a fully printable process.

  18. Restoration of solar and star images with phase diversity-based blind deconvolution

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Liao, Sheng; Wei, Honggang; Shen, Mangzuo

    2007-04-01

    The images recorded by a ground-based telescope are often degraded by atmospheric turbulence and the aberration of the optical system. Phase diversity-based blind deconvolution is an effective post-processing method that can be used to overcome the turbulence-induced degradation. The method uses an ensemble of short-exposure images obtained simultaneously from multiple cameras to jointly estimate the object and the wavefront distribution on pupil. Based on signal estimation theory and optimization theory, we derive the cost function and solve the large-scale optimization problem using a limited memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) method. We apply the method to the turbulence-degraded images generated with computer, the solar images acquired with the swedish vacuum solar telescope (SVST, 0.475 m) in La Palma and the star images collected with 1.2-m telescope in Yunnan Observatory. In order to avoid edge effect in the restoration of the solar images, a modified Hanning apodized window is adopted. The star image still can be restored when the defocus distance is measured inaccurately. The restored results demonstrate that the method is efficient for removing the effect of turbulence and reconstructing the point-like or extended objects.

  19. Efficient Regular Perovskite Solar Cells Based on Pristine [70]Fullerene as Electron-Selective Contact.

    PubMed

    Collavini, Silvia; Kosta, Ivet; Völker, Sebastian F; Cabanero, German; Grande, Hans J; Tena-Zaera, Ramón; Delgado, Juan Luis

    2016-06-08

    [70]Fullerene is presented as an efficient alternative electron-selective contact (ESC) for regular-architecture perovskite solar cells (PSCs). A smart and simple, well-described solution processing protocol for the preparation of [70]- and [60]fullerene-based solar cells, namely the fullerene saturation approach (FSA), allowed us to obtain similar power conversion efficiencies for both fullerene materials (i.e., 10.4 and 11.4 % for [70]- and [60]fullerene-based devices, respectively). Importantly, despite the low electron mobility and significant visible-light absorption of [70]fullerene, the presented protocol allows the employment of [70]fullerene as an efficient ESC. The [70]fullerene film thickness and its solubility in the perovskite processing solutions are crucial parameters, which can be controlled by the use of this simple solution processing protocol. The damage to the [70]fullerene film through dissolution during the perovskite deposition is avoided through the saturation of the perovskite processing solution with [70]fullerene. Additionally, this fullerene-saturation strategy improves the performance of the perovskite film significantly and enhances the power conversion efficiency of solar cells based on different ESCs (i.e., [60]fullerene, [70]fullerene, and TiO2 ). Therefore, this universal solution processing protocol widens the opportunities for the further development of PSCs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Stable solvent for solution-based electrical doping of semiconducting polymer films and its application to organic solar cells

    DOE PAGES

    Larrain, Felipe A.; Fuentes-Hernandez, Canek; Chou, Wen-Fang; ...

    2018-01-01

    A solution-based method to electrically p-dope organic semiconductors enabling the fabrication of organic solar cells with simplified geometry is implemented with acetonitrile as an alternative to nitromethane.

  1. 75 FR 76726 - San Luis Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-09

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-2196-000] San Luis Solar, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket... proceeding of San Luis [[Page 76727

  2. 76 FR 26282 - NRG Solar Roadrunner LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-06

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-3459-000] NRG Solar Roadrunner LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket... 26283

  3. Stable solvent for solution-based electrical doping of semiconducting polymer films and its application to organic solar cells

    SciTech Connect

    Larrain, Felipe A.; Fuentes-Hernandez, Canek; Chou, Wen-Fang

    A solution-based method to electrically p-dope organic semiconductors enabling the fabrication of organic solar cells with simplified geometry is implemented with acetonitrile as an alternative to nitromethane.

  4. Positive temperature coefficient of photovoltaic efficiency in solar cells based on InGaN/GaN MQWs

    SciTech Connect

    Chen, Zhaoying; Zheng, Xiantong; Li, Zhilong

    2016-08-08

    We report a 23.4% improvement of conversion efficiency in solar cells based on InGaN/GaN multiple quantum wells by using a patterned sapphire substrate in the fabrication process. The efficiency enhancement is due to the improvement of the crystalline quality, as proven by the reduction of the threading dislocation density. More importantly, the better crystalline quality leads to a positive photovoltaic efficiency temperature coefficient up to 423 K, which shows the property and advantage of wide gap semiconductors like InGaN, signifying the potential of III-nitride based solar cells for high temperature and concentrating solar power applications.

  5. Electrophoretic deposited TiO 2 pigment-based back reflectors for thin film solar cells

    DOE PAGES

    Bills, Braden; Morris, Nathan; Dubey, Mukul; ...

    2015-01-16

    Highly reflective coatings with strong light scattering effect have many applications in optical components and optoelectronic devices. This paper reports titanium dioxide (TiO 2) pigment-based reflectors that have 2.5 times higher broadband diffuse reflection than commercially produced aluminum or silver based reflectors and result in efficiency enhancements of a single-junction amorphous Si solar cell. Electrophoretic deposition is used to produce pigment-based back reflectors with high pigment density, controllable film thickness and site-specific deposition. Electrical conductivity of the pigment-based back reflectors is improved by creating electrical vias throughout the pigment-based back reflector by making holes using an electrical discharge / dielectricmore » breakdown approach followed by a second electrophoretic deposition of conductive nanoparticles into the holes. While previous studies have demonstrated the use of pigment-based back reflectors, for example white paint, on glass superstrate configured thin film Si solar cells, this work presents a scheme for producing pigment-based reflectors on complex shape and flexible substrates. Finally, mechanical durability and scalability are demonstrated on a continuous electrophoretic deposition roll-to-roll system which has flexible metal substrate capability of 4 inch wide and 300 feet long.« less

  6. Evaluating the spatio-temporal performance of sky imager based solar irradiance analysis and forecasts

    NASA Astrophysics Data System (ADS)

    Schmidt, T.; Kalisch, J.; Lorenz, E.; Heinemann, D.

    2015-10-01

    Clouds are the dominant source of variability in surface solar radiation and uncertainty in its prediction. However, the increasing share of solar energy in the world-wide electric power supply increases the need for accurate solar radiation forecasts. In this work, we present results of a shortest-term global horizontal irradiance (GHI) forecast experiment based on hemispheric sky images. A two month dataset with images from one sky imager and high resolutive GHI measurements from 99 pyranometers distributed over 10 km by 12 km is used for validation. We developed a multi-step model and processed GHI forecasts up to 25 min with an update interval of 15 s. A cloud type classification is used to separate the time series in different cloud scenarios. Overall, the sky imager based forecasts do not outperform the reference persistence forecasts. Nevertheless, we find that analysis and forecast performance depend strongly on the predominant cloud conditions. Especially convective type clouds lead to high temporal and spatial GHI variability. For cumulus cloud conditions, the analysis error is found to be lower than that introduced by a single pyranometer if it is used representatively for the whole area in distances from the camera larger than 1-2 km. Moreover, forecast skill is much higher for these conditions compared to overcast or clear sky situations causing low GHI variability which is easier to predict by persistence. In order to generalize the cloud-induced forecast error, we identify a variability threshold indicating conditions with positive forecast skill.

  7. Hysteresis Analysis Based on the Ferroelectric Effect in Hybrid Perovskite Solar Cells.

    PubMed

    Wei, Jing; Zhao, Yicheng; Li, Heng; Li, Guobao; Pan, Jinlong; Xu, Dongsheng; Zhao, Qing; Yu, Dapeng

    2014-11-06

    The power conversion efficiency (PCE) of CH3NH3PbX3 (X = I, Br, Cl) perovskite solar cells has been developed rapidly from 6.5 to 18% within 3 years. However, the anomalous hysteresis found in I-V measurements can cause an inaccurate estimation of the efficiency. We attribute the phenomena to the ferroelectric effect and build a model based on the ferroelectric diode to explain it. The ferroelectric effect of CH3NH3PbI3-xClx is strongly suggested by characterization methods and the E-P (electrical field-polarization) loop. The hysteresis in I-V curves is found to greatly depend on the scan range as well as the velocity, which is well explained by the ferroelectric diode model. We also find that the current signals show exponential decay in ∼10 s under prolonged stepwise measurements, and the anomalous hysteresis disappears using these stabilized current values. The experimental results accord well with the model based on ferroelectric properties and prove that prolonged stepwise measurement is an effective way to evaluate the real efficiency of perovskite solar cells. Most importantly, this work provides a meaningful perspective that the ferroelectric effect (if it really exists) should be paid special attention in the optimization of perovskite solar cells.

  8. Direct X-ray detection with hybrid solar cells based on organolead halide perovskites

    NASA Astrophysics Data System (ADS)

    Gill, Hardeep Singh; Elshahat, Bassem; Sajo, Erno; Kumar, Jayant; Kokil, Akshay; Zygmanski, Piotr; Li, Lian; Mosurkal, Ravi

    2014-03-01

    Organolead halide perovskite materials are attracting considerable interest due to their exceptional opto-electronic properties, such as, high charge carrier mobilities, high exciton diffusion length, high extinction coefficients and broad-band absorption. These interesting properties have enabled their application in high performance hybrid photovoltaic devices. The high Z value of their constituents also makes these materials efficient for absorbing X-rays. Here we will present on the efficient use of hybrid solar cells based on organolead perovskite materials as X-ray detectors. Hybrid solar cells based on CH3NH3PbI3 were fabricated using facile processing techniques on patterned indium tin oxide coated glass substrates. The solar cells typically had a planar configuration of ITO/CH3NH3PbI3/P3HT/Ag. High sensitivity for X-rays due to high Z value, larger carrier mobility and better charge collection was observed. Detecting X-rays with energies relevant to medical oncology applications opens up the potential for diagnostic imaging applications.

  9. Perovskites-Based Solar Cells: A Review of Recent Progress, Materials and Processing Methods

    PubMed Central

    Shi, Zhengqi; Jayatissa, Ahalapitiya H.

    2018-01-01

    With the rapid increase of efficiency up to 22.1% during the past few years, hybrid organic-inorganic metal halide perovskite solar cells (PSCs) have become a research “hot spot” for many solar cell researchers. The perovskite materials show various advantages such as long carrier diffusion lengths, widely-tunable band gap with great light absorption potential. The low-cost fabrication techniques together with the high efficiency makes PSCs comparable with Si-based solar cells. But the drawbacks such as device instability, J-V hysteresis and lead toxicity reduce the further improvement and the future commercialization of PSCs. This review begins with the discussion of crystal and electronic structures of perovskite based on recent research findings. An evolution of PSCs is also analyzed with a greater detail of each component, device structures, major device fabrication methods and the performance of PSCs acquired by each method. The following part of this review is the discussion of major barriers on the pathway for the commercialization of PSCs. The effects of crystal structure, fabrication temperature, moisture, oxygen and UV towards the stability of PSCs are discussed. The stability of other components in the PSCs are also discussed. The lead toxicity and updated research progress on lead replacement are reviewed to understand the sustainability issues of PSCs. The origin of J-V hysteresis is also briefly discussed. Finally, this review provides a roadmap on the current needs and future research directions to address the main issues of PSCs. PMID:29734667

  10. Solar tower cavity receiver aperture optimization based on transient optical and thermo-hydraulic modeling

    NASA Astrophysics Data System (ADS)

    Schöttl, Peter; Bern, Gregor; van Rooyen, De Wet; Heimsath, Anna; Fluri, Thomas; Nitz, Peter

    2017-06-01

    A transient simulation methodology for cavity receivers for Solar Tower Central Receiver Systems with molten salt as heat transfer fluid is described. Absorbed solar radiation is modeled with ray tracing and a sky discretization approach to reduce computational effort. Solar radiation re-distribution in the cavity as well as thermal radiation exchange are modeled based on view factors, which are also calculated with ray tracing. An analytical approach is used to represent convective heat transfer in the cavity. Heat transfer fluid flow is simulated with a discrete tube model, where the boundary conditions at the outer tube surface mainly depend on inputs from the previously mentioned modeling aspects. A specific focus is put on the integration of optical and thermo-hydraulic models. Furthermore, aiming point and control strategies are described, which are used during the transient performance assessment. Eventually, the developed simulation methodology is used for the optimization of the aperture opening size of a PS10-like reference scenario with cavity receiver and heliostat field. The objective function is based on the cumulative gain of one representative day. Results include optimized aperture opening size, transient receiver characteristics and benefits of the implemented aiming point strategy compared to a single aiming point approach. Future work will include annual simulations, cost assessment and optimization of a larger range of receiver parameters.

  11. Spectral Atlas of X-ray Lines Emitted During Solar Flares Based on CHIANTI

    NASA Technical Reports Server (NTRS)

    Landi, E.; Phillips, K. J. H.

    2005-01-01

    A spectral atlas of X-ray lines in the wavelength range 7.47-18.97 Angstroms is presented, based on high-resolution spectra obtained during two M-class solar flares (on 1980 August 25 and 1985 July 2) with the Flat Crystal Spectrometer on board the Solar Maximum Mission. The physical properties of the flaring plasmas are derived as a function of time using strong, isolated lines. From these properties predicted spectra using the CHIANTI database have been obtained which were then compared with wavelengths and fluxes of lines in the observed spectra to establish line identifications. identifications for nearly all the observed lines in the resulting atlas are given, with some significant corrections to previous analysis of these flare spectra.

  12. Liquid-phase-deposited siloxane-based capping layers for silicon solar cells

    SciTech Connect

    Veith-Wolf, Boris; Wang, Jianhui; Hannu-Kuure, Milja

    2015-02-02

    We apply non-vacuum processing to deposit dielectric capping layers on top of ultrathin atomic-layer-deposited aluminum oxide (AlO{sub x}) films, used for the rear surface passivation of high-efficiency crystalline silicon solar cells. We examine various siloxane-based liquid-phase-deposited (LPD) materials. Our optimized AlO{sub x}/LPD stacks show an excellent thermal and chemical stability against aluminum metal paste, as demonstrated by measured surface recombination velocities below 10 cm/s on 1.3 Ωcm p-type silicon wafers after firing in a belt-line furnace with screen-printed aluminum paste on top. Implementation of the optimized LPD layers into an industrial-type screen-printing solar cell process results in energy conversion efficiencies ofmore » up to 19.8% on p-type Czochralski silicon.« less

  13. Fabrication and characterization of dye-sensitized solar cells based on natural plants

    NASA Astrophysics Data System (ADS)

    Gu, Peng; Yang, Dingyu; Zhu, Xinghua; Sun, Hui; Li, Jitao

    2018-02-01

    In this paper, the dye-sensitized solar cells (DSSCs) were fabricated based on natural dyes extracting from carrot, mulberry, purple cabbage, potato, and grapes. The ultraviolet-visible spectra suggested purple cabbage and mulberry possess better absorption at 300-550 nm. The solar cells using purple cabbage as dye achieved a conversion efficiency of 0.162% with short-circuit photocurrent density (Jsc) of 0.621 mA/cm2, open circuit voltage (Voc) of 0.541 V and fill factor (FF) of 0.484. The Infrared spectra revealed the bond of Osbnd H, Csbnd C, Csbnd O, Csbnd H were existed in purple cabbage. Finally, the optimal extraction time of dyes is also presented.

  14. Smart photovoltaics based on dye-sensitized solar cells using photochromic spiropyran derivatives as photosensitizers

    SciTech Connect

    Ma, Shengbo; Ting, Hungkit; Ma, Yingzhuang

    2015-05-15

    In this paper, smart photovoltaic (SPV) devices, integrating both functions of solar cells and smart windows, was fabricated based on dye-sensitized solar cells using photochromic spiropyran derivatives SIBT as photosensitizers. SPV devices have self-regulated power conversion efficiency (PCE) and light transmission responding to the incident spectra due to the photoisomerization of SIBT. SIBT isomerize from closed-ring form to open-ring form under UV illumination, accompanied with enhanced visible light absorption and electron delocalization. Therefore, increased PCE and absorption in SPV devices were observed under UV treatment and the devices can be restored gradually to the initial status when kept in dark.more » The SPV devices have self-regulation of PCE and sunlight transmission responding to the changing sun spectra in different times of a day, providing a proper energy usage and a better sun-shading.« less

  15. Wire-shaped perovskite solar cell based on TiO2 nanotubes

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoyan; Kulkarni, Sneha A.; Li, Zhen; Xu, Wenjing; Batabyal, Sudip K.; Zhang, Sam; Cao, Anyuan; Wong, Lydia Helena

    2016-05-01

    In this work, a wire-shaped perovskite solar cell based on TiO2 nanotube (TNT) arrays is demonstrated for the first time by integrating a perovskite absorber on TNT-coated Ti wire. Anodization was adopted for the conformal growth of TNTs on Ti wire, together with the simultaneous formation of a compact TiO2 layer. A sequential step dipping process is employed to produce a uniform and compact perovskite layer on top of TNTs with conformal coverage as the efficient light absorber. Transparent carbon nanotube film is wrapped around Ti wire as the hole collector and counter electrode. The integrated perovskite solar cell wire by facile fabrication approaches shows a promising future in portable and wearable textile electronics.

  16. Thin film solar cell design based on photonic crystal and diffractive grating structures.

    PubMed

    Mutitu, James G; Shi, Shouyuan; Chen, Caihua; Creazzo, Timothy; Barnett, Allen; Honsberg, Christiana; Prather, Dennis W

    2008-09-15

    In this paper we present novel light trapping designs applied to multiple junction thin film solar cells. The new designs incorporate one dimensional photonic crystals as band pass filters that reflect short light wavelengths (400 - 867 nm) and transmit longer wavelengths(867 -1800 nm) at the interface between two adjacent cells. In addition, nano structured diffractive gratings that cut into the photonic crystal layers are incorporated to redirect incoming waves and hence increase the optical path length of light within the solar cells. Two designs based on the nano structured gratings that have been realized using the scattering matrix and particle swarm optimization methods are presented. We also show preliminary fabrication results of the proposed devices.

  17. Photocatalytic Removal of Microcystin-LR by Advanced WO3-Based Nanoparticles under Simulated Solar Light

    PubMed Central

    Zhao, Chao; Li, Dawei; Feng, Chuanping; Zhang, Zhenya; Sugiura, Norio; Yang, Yingnan

    2015-01-01

    A series of advanced WO3-based photocatalysts including CuO/WO3, Pd/WO3, and Pt/WO3 were synthesized for the photocatalytic removal of microcystin-LR (MC-LR) under simulated solar light. In the present study, Pt/WO3 exhibited the best performance for the photocatalytic degradation of MC-LR. The MC-LR degradation can be described by pseudo-first-order kinetic model. Chloride ion (Cl−) with proper concentration could enhance the MC-LR degradation. The presence of metal cations (Cu2+ and Fe3+) improved the photocatalytic degradation of MC-LR. This study suggests that Pt/WO3 photocatalytic oxidation under solar light is a promising option for the purification of water containing MC-LR. PMID:25884038

  18. Attractive manifold-based adaptive solar attitude control of satellites in elliptic orbits

    NASA Astrophysics Data System (ADS)

    Lee, Keum W.; Singh, Sahjendra N.

    2011-01-01

    The paper presents a novel noncertainty-equivalent adaptive (NCEA) control system for the pitch attitude control of satellites in elliptic orbits using solar radiation pressure (SRP). The satellite is equipped with two identical solar flaps to produce control moments. The adaptive law is based on the attractive manifold design using filtered signals for synthesis, which is a modification of the immersion and invariance (I&I) method. The control system has a modular controller-estimator structure and has separate tunable gains. A special feature of this NCEA law is that the trajectories of the satellite converge to a manifold in an extended state space, and the adaptive law recovers the performance of a deterministic controller. This recovery of performance cannot be obtained with certainty-equivalent adaptive (CEA) laws. Simulation results are presented which show that the NCEA law accomplishes precise attitude control of the satellite in an elliptic orbit, despite large parameter uncertainties.

  19. Physics-Based GOES Product for Use in NREL's National Solar Radiation Database: Preprint

    SciTech Connect

    Sengupta, Manajit; Habte, Aron; Gotseff, Peter

    The Global Solar Insolation Project (GSIP) is an operational physical model from the National Oceanic and Atmospheric Administration (NOAA) that computes global horizontal radiation (GHI) using the visible and infrared channel measurements from geostationary operational environmental satellites (GOES). GSIP uses a two-stage scheme that retrieves cloud properties and uses those properties in the Satellite Algorithm for Surface Radiation Budget (SASRAB) model to calculate surface radiation. The National Renewable Energy Laboratory, University of Wisconsin, and NOAA have recently collaborated to adapt GSIP to create a high-temporal and spatial resolution data set. The data sets are currently being incorporated into the widelymore » used National Solar Radiation Data Base.« less

  20. Space-based solar power conversion and delivery systems study. Volume 3: Economic analysis of space-based solar power systems

    NASA Technical Reports Server (NTRS)

    Hazelrigg, G. A., Jr.

    1976-01-01

    A variety of economic and programmatic issues are discussed concerning the development and deployment of a fleet of space-based solar power satellites (SSPS). The costs, uncertainties and risks associated with the current photovoltaic SSPS configuration, and with issues affecting the development of an economically viable SSPS development program are analyzed. The desirability of a low earth orbit (LEO) demonstration satellite and a geosynchronous (GEO) pilot satellite is examined and critical technology areas are identified. In addition, a preliminary examination of utility interface issues is reported. The main focus of the effort reported is the development of SSPS unit production, and operation and maintenance cost models suitable for incorporation into a risk assessment (Monte Carlo) model (RAM). It is shown that the key technology area deals with the productivity of man in space, not, as might be expected, with some hardware component technology.

  1. Automatic vision-based grain optimization and analysis of multi-crystalline solar wafers using hierarchical region growing

    NASA Astrophysics Data System (ADS)

    Fan, Shu-Kai S.; Tsai, Du-Ming; Chuang, Wei-Che

    2017-04-01

    Solar power has become an attractive alternative source of energy. The multi-crystalline solar cell has been widely accepted in the market because it has a relatively low manufacturing cost. Multi-crystalline solar wafers with larger grain sizes and fewer grain boundaries are higher quality and convert energy more efficiently than mono-crystalline solar cells. In this article, a new image processing method is proposed for assessing the wafer quality. An adaptive segmentation algorithm based on region growing is developed to separate the closed regions of individual grains. Using the proposed method, the shape and size of each grain in the wafer image can be precisely evaluated. Two measures of average grain size are taken from the literature and modified to estimate the average grain size. The resulting average grain size estimate dictates the quality of the crystalline solar wafers and can be considered a viable quantitative indicator of conversion efficiency.

  2. Update of the ISTP Solar Maximum Mission: ISTP Project Scientist for Theory and Ground-Based Observations

    NASA Technical Reports Server (NTRS)

    Curtis, Steve

    1999-01-01

    Building upon the numerous successes of the pre-solar maximum International Solar Terrestrial Physics (ISTP) mission, the ISTP Solar Maximum Mission is expected to produce new insights into global flow of energy, momentum, and mass, from the Sun, through the heliosphere, into the magnetosphere and to their final deposition in the terrestrial upper atmosphere/ionosphere system. Of particular interest is the determination of the geo-effectiveness of solar events, principally Coronal Mass Ejections (CMEs). Given the expected increased frequency and strength of CMEs during the Solar Maximum period, a major advance in our understanding of nature of the coupling of CMEs to the magnetosphere-ionosphere-atmosphere system is expected. The roles during this time of the various ISTP assets will be discussed. These assets will include the SOHO, Wind, Polar, and Geotail spacecraft, the ground-based observing networks and the theory tools.

  3. Feasibility Study of Space Based Solar Power to Tethered Aerostat Systems

    NASA Technical Reports Server (NTRS)

    Blank, Stephen J.; Leete, Stephen J.; Jaffe, Paul

    2013-01-01

    The feasibility of two-stage Space-Based Solar Power to Tethered Aerostat to Earth (SSP-TA) system architectures that offer significant advantages over conventional single stage space-to-earth architectures is being studied. There have been many proposals for the transmission of solar power collected in space to the surface of the earth so that solar energy could provide a major part of the electric power requirements on earth. There are, however, serious difficulties in implementing the single stage space-based solar power systems that have been previously studied. These difficulties arise due to: i) the cost of transporting the components needed for the extremely large microwave transmit beaming aperture into space orbit, ii) the even larger collection apertures required on earth, iii) the potential radiation hazard to personnel and equipment on earth, and iv) a lack of flexibility in location of the collection station on the earth. Two candidate system architectures are described here to overcome these difficulties. In both cases a two-stage space to tethered aerostat to earth transmission system (SSP-TA) is proposed. The use of high altitude tethered aerostats (or powered airships) avoids the effects of attenuation of EM energy propagating through the earth s lower atmosphere. This allows the use of beaming frequencies to be chosen from the range of high millimeter (THz) to near-infra-red (NIR) to the visible. This has the potential for: i) greatly reduced transportation costs to space, ii) much smaller receiver collection apertures and ground stations, iii) elimination of the potential radiation hazard to personnel and equipment on earth, and iv) ease in transportation and flexibility in location of the collection station on the earth. A preliminary comparison of system performance and efficiencies is presented.

  4. High precision dual-axis tracking solar wireless charging system based on the four quadrant photoelectric sensor

    NASA Astrophysics Data System (ADS)

    Liu, Zhilong; Wang, Biao; Tong, Weichao

    2015-08-01

    This paper designs a solar automatic tracking wireless charging system based on the four quadrant photoelectric sensor. The system track the sun's rays automatically in real time to received the maximum energy and wireless charging to the load through electromagnetic coupling. Four quadrant photoelectric sensor responsive to the solar spectrum, the system could get the current azimuth and elevation angle of the light by calculating the solar energy incident on the sensor profile. System driver the solar panels by the biaxial movement mechanism to rotate and tilt movement until the battery plate and light perpendicular to each other. Maximize the use of solar energy, and does not require external power supply to achieve energy self-sufficiency. Solar energy can be collected for portable devices and load wireless charging by close electromagnetic field coupling. Experimental data show that: Four quadrant photoelectric sensor more sensitive to light angle measurement. when track positioning solar light, Azimuth deviation is less than 0.8°, Elevation angle deviation is less than 0.6°. Use efficiency of a conventional solar cell is only 10% -20%.The system uses a Four quadrant dual-axis tracking to raise the utilization rate of 25% -35%.Wireless charging electromagnetic coupling efficiency reached 60%.

  5. Concentrated solar power generation using solar receivers

    SciTech Connect

    Anderson, Bruce N.; Treece, William Dean; Brown, Dan

    Inventive concentrated solar power systems using solar receivers, and related devices and methods, are generally described. Low pressure solar receivers are provided that function to convert solar radiation energy to thermal energy of a working fluid, e.g., a working fluid of a power generation or thermal storage system. In some embodiments, low pressure solar receivers are provided herein that are useful in conjunction with gas turbine based power generation systems.

  6. CH₃NH₃PbI₃-based planar solar cells with magnetron-sputtered nickel oxide.

    PubMed

    Cui, Jin; Meng, Fanping; Zhang, Hua; Cao, Kun; Yuan, Huailiang; Cheng, Yibing; Huang, Feng; Wang, Mingkui

    2014-12-24

    Herein we report an investigation of a CH3NH3PbI3 planar solar cell, showing significant power conversion efficiency (PCE) improvement from 4.88% to 6.13% by introducing a homogeneous and uniform NiO blocking interlayer fabricated with the reactive magnetron sputtering method. The sputtered NiO layer exhibits enhanced crystallization, high transmittance, and uniform surface morphology as well as a preferred in-plane orientation of the (200) plane. The PCE of the sputtered-NiO-based perovskite p-i-n planar solar cell can be further promoted to 9.83% when a homogeneous and dense perovskite layer is formed with solvent-engineering technology, showing an impressive open circuit voltage of 1.10 V. This is about 33% higher than that of devices using the conventional spray pyrolysis of NiO onto a transparent conducting glass. These results highlight the importance of a morphology- and crystallization-compatible interlayer toward a high-performance inverted perovskite planar solar cell.

  7. Machine learning-based screening of complex molecules for polymer solar cells

    NASA Astrophysics Data System (ADS)

    Jørgensen, Peter Bjørn; Mesta, Murat; Shil, Suranjan; García Lastra, Juan Maria; Jacobsen, Karsten Wedel; Thygesen, Kristian Sommer; Schmidt, Mikkel N.

    2018-06-01

    Polymer solar cells admit numerous potential advantages including low energy payback time and scalable high-speed manufacturing, but the power conversion efficiency is currently lower than for their inorganic counterparts. In a Phenyl-C_61-Butyric-Acid-Methyl-Ester (PCBM)-based blended polymer solar cell, the optical gap of the polymer and the energetic alignment of the lowest unoccupied molecular orbital (LUMO) of the polymer and the PCBM are crucial for the device efficiency. Searching for new and better materials for polymer solar cells is a computationally costly affair using density functional theory (DFT) calculations. In this work, we propose a screening procedure using a simple string representation for a promising class of donor-acceptor polymers in conjunction with a grammar variational autoencoder. The model is trained on a dataset of 3989 monomers obtained from DFT calculations and is able to predict LUMO and the lowest optical transition energy for unseen molecules with mean absolute errors of 43 and 74 meV, respectively, without knowledge of the atomic positions. We demonstrate the merit of the model for generating new molecules with the desired LUMO and optical gap energies which increases the chance of finding suitable polymers by more than a factor of five in comparison to the randomised search used in gathering the training set.

  8. Visualization Based Data Mining for Comparison Between Two Solar Cell Libraries.

    PubMed

    Yosipof, Abraham; Kaspi, Omer; Majhi, Koushik; Senderowitz, Hanoch

    2016-12-01

    Material informatics may provide meaningful insights and powerful predictions for the development of new and efficient Metal Oxide (MO) based solar cells. The main objective of this paper is to establish the usefulness of data reduction and visualization methods for analyzing data sets emerging from multiple all-MOs solar cell libraries. For this purpose, two libraries, TiO 2 |Co 3 O 4 and TiO 2 |Co 3 O 4 |MoO 3 , differing only by the presence of a MoO 3 layer in the latter were analyzed with Principal Component Analysis and Self-Organizing Maps. Both analyses suggest that the addition of the MoO 3 layer to the TiO 2 |Co 3 O 4 library has affected the overall photovoltaic (PV) activity profile of the solar cells making the two libraries clearly distinguishable from one another. Furthermore, while MoO 3 had an overall favorable effect on PV parameters, a sub-population of cells was identified which were either indifferent to its presence or even demonstrated a reduction in several parameters. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Installed Base Registration of Decentralised Solar Panels with Applications in Crisis Management

    NASA Astrophysics Data System (ADS)

    Aarsen, R.; Janssen, M.; Ramkisoen, M.; Biljecki, F.; Quak, W.; Verbree, E.

    2015-08-01

    In case of a calamity in the Netherlands - e.g. a dike breach - parts of the nationwide electric network can fall out. In these occasions it would be useful if decentralised energy sources of the Smart Grid would contribute to balance out the fluctuations of the energy network. Decentralised energy sources include: solar energy, wind energy, combined heat and power, and biogas. In this manner, parts of the built environment - e.g. hospitals - that are in need of a continuous power flow, could be secured of this power. When a calamity happens, information about the Smart Grid is necessary to control the crisis and to ensure a shared view on the energy networks for both the crisis managers and network operators. The current situation of publishing, storing and sharing data of solar energy has been shown a lack of reliability about the current number, physical location, and capacity of installed decentralised photovoltaic (PV) panels in the Netherlands. This study focuses on decentralised solar energy in the form of electricity via PV panels in the Netherlands and addresses this challenge by proposing a new, reliable and up-to-date database. The study reveals the requirements for a registration of the installed base of PV panels in the Netherlands. This new database should serve as a replenishment for the current national voluntary registration, called Production Installation Register of Energy Data Services Netherland (EDSN-PIR), of installed decentralised PV panel installations in the Smart Grid, and provide important information in case of a calamity.

  10. A New Lead Iodide Perovskite based on Large Organic Cation for Solar Cell Application.

    PubMed

    Ma, Chunqing; Shen, Dong; Lo, Ming Fai; Lee, Chun-Sing

    2018-06-06

    Methylammonium (CH3NH3+) and formamidinium ((NH2)2CH+) based lead iodide perovskites are currently the two commonly used organic-inorganic lead iodide perovskites for solar cell application. Till now, there is still no alternative organic cations, which can produce perovskites with bandgaps spanning the visible spectrum (i.e. < 1.7 eV) for solar cell application. Here, a new perovskite using large propane-1,3-diammonium cation (n-Pr(NH3)22+) with a chemical structure of (n-Pr(NH3)2)0.5PbI3 is demonstrated. X-ray diffraction (XRD) result shows that the new perovskite exhibits a three-dimensional (3D), tetragonal phase. The bandgap of the new perovskite is ~ 1.6 eV, which is desirable for photovoltaic application. A (n-Pr(NH3)2)0.5PbI3 perovskite solar cell (PSC) yields a power conversion efficiency (PCE) of 5.1%. More importantly, this new perovskite is composed of larger hydrophobic cation that provides a better moisture resistance compared to CH3NH3PbI3 perovskite. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Hybrid heterojunction solar cell based on organic-inorganic silicon nanowire array architecture.

    PubMed

    Shen, Xiaojuan; Sun, Baoquan; Liu, Dong; Lee, Shuit-Tong

    2011-12-07

    Silicon nanowire arrays (SiNWs) on a planar silicon wafer can be fabricated by a simple metal-assisted wet chemical etching method. They can offer an excellent light harvesting capability through light scattering and trapping. In this work, we demonstrated that the organic-inorganic solar cell based on hybrid composites of conjugated molecules and SiNWs on a planar substrate yielded an excellent power conversion efficiency (PCE) of 9.70%. The high efficiency was ascribed to two aspects: one was the improvement of the light absorption by SiNWs structure on the planar components; the other was the enhancement of charge extraction efficiency, resulting from the novel top contact by forming a thin organic layer shell around the individual silicon nanowire. On the contrary, the sole planar junction solar cell only exhibited a PCE of 6.01%, due to the lower light trapping capability and the less hole extraction efficiency. It indicated that both the SiNWs structure and the thin organic layer top contact were critical to achieve a high performance organic/silicon solar cell. © 2011 American Chemical Society

  12. Dynamo-based scheme for forecasting the magnitude of solar activity cycles

    NASA Technical Reports Server (NTRS)

    Layden, A. C.; Fox, P. A.; Howard, J. M.; Sarajedini, A.; Schatten, K. H.

    1991-01-01

    This paper presents a general framework for forecasting the smoothed maximum level of solar activity in a given cycle, based on a simple understanding of the solar dynamo. This type of forecasting requires knowledge of the sun's polar magnetic field strength at the preceding activity minimum. Because direct measurements of this quantity are difficult to obtain, the quality of a number of proxy indicators already used by other authors is evaluated, which are physically related to the sun's polar field. These indicators are subjected to a rigorous statistical analysis, and the analysis technique for each indicator is specified in detail in order to simplify and systematize reanalysis for future use. It is found that several of these proxies are in fact poorly correlated or uncorrelated with solar activity, and thus are of little value for predicting activity maxima. Also presented is a scheme in which the predictions of the individual proxies are combined via an appropriately weighted mean to produce a compound prediction. The scheme is then applied to the current cycle 22, and a maximum smoothed international sunspot number of 171 + or - 26 is estimated.

  13. A novel strategy to increase separated electron-hole dipoles in commercial Si based solar panel to assist photovoltaic effect

    NASA Astrophysics Data System (ADS)

    Feng, Yefeng; He, Cheng-En; Xu, Zhichao; Hu, Jianbing; Peng, Cheng

    2018-01-01

    Interface induced polarization has been found to have a significant impact on dielectric properties of 2-2 type polymer composites bearing Si based semi-conducting ceramic sheets. Inherent overall polarity of polymer layers in 2-2 composites has been verified to be closely connected with interface effect and achieved permittivity in composites. In present work, conducting performances of monocrystalline Si sheets coated by varied high polarity material layers were deeply researched. The positive results inspired us to propose a novel strategy to improve separated electron-hole dipoles in commercial Si based solar cell panel for assisting photovoltaic effect, based on strong interface induced polarization. Conducting features of solar panels coated by two different high polarity polymer layers were detected to be greatly elevated compared with solar panel standalone, thanks to interface induced polarization between panel and polymer. Polymer coating with higher polarity would lead to more separated electron-hole dipole pairs in solar panel contributing to higher conductivity of panel. Valid synergy of interface effect and photovoltaic effect was based on their unidirectional traits of electron transfer. Dielectric properties of solar panels in composites further confirmed that strategy. This work might provide a facile route to prepare promising Si based solar panels with higher photoelectric conversion efficiency by enhancing interface induced polarization between panel and polymer coating.

  14. The AIA Solar Learning Center: Taking Inquiry-based EPO Online

    NASA Astrophysics Data System (ADS)

    Wills-Davey, Meredith; Attrill, G. D. R.; Engell, A.

    2009-05-01

    The observations of the Atmospheric Imaging Assembly aboard the Solar Dynamics Observatory (SDO-AIA) are expected to be groundbreaking within the field of heliophysics. To properly promote and explain the data produced by AIA, it is important that an innovative EPO effort be put forth. This has led to the development of "The AIA Solar Learning Center” (SLC), an inquiry-based educational website geared towards teaching about AIA and the Sun in general. The goal of the SLC is to provide K-12 students, teachers, parents, and homeschoolers with information and education about the Sun, primarily through hands-on activity modules that explain different aspects of our nearest star and the methods of observing it. While each module ultimately aims to impart information about the Sun or some related physical process, the activities also range across a host of different disciplines, including geology, chemistry, history, music, and art. In order to make the content applicable and accessible, activities are tailored to multiple difficulty levels, catering to different age groups. There is also a strong push towards facilitating teachers; activities are designed to fulfill specific teaching standards, and a host of additional teaching material is provided, including lesson plans and powerpoint presentations. Ultimately, the SLC aims to make science and the Sun inviting and accessible. The "Meet the Scientists” page will provide pictures and personal bios of participating scientists. Students will have the opportunity to interactively ask solar-related questions. There is even a host of lighter fare, such as a solar music playlist and links to relevant Facebook pages.

  15. Multifunctional microstructured polymer films for boosting solar power generation of silicon-based photovoltaic modules.

    PubMed

    Leem, Jung Woo; Choi, Minkyu; Yu, Jae Su

    2015-02-04

    We propose two-dimensional periodic conical micrograting structured (MGS) polymer films as a multifunctional layer (i.e., light harvesting and self-cleaning) at the surface of outer polyethylene terephthalate (PET) cover-substrates for boosting the solar power generation in silicon (Si)-based photovoltaic (PV) modules. The surface of ultraviolet-curable NOA63 MGS polymer films fabricated by the soft imprint lithography exhibits a hydrophobic property with water contact angle of ∼121° at no inclination and dynamic advancing/receding water contact angles of ∼132°/111° at the inclination angle of 40°, respectively, which can remove dust particles or contaminants on the surface of PV modules in real outdoor environments (i.e., self-cleaning). The NOA63 MGS film coated on the bare PET leads to the reduction of reflection as well as the enhancement of both the total and diffuse transmissions at wavelengths of 300-1100 nm, indicating lower solar weighted reflectance (RSW) of ∼8.2%, higher solar weighted transmittance (TSW) of ∼93.1%, and considerably improved average haze ratio (HAvg) of ∼88.3% as compared to the bare PET (i.e., RSW ≈ 13.5%, TSW ≈ 86.9%, and HAvg ≈ 9.1%), respectively. Additionally, it shows a relatively good durability at temperatures of ≤160 °C. The resulting Si PV module with the NOA63 MGS/PET has an enhanced power conversion efficiency (PCE) of 13.26% (cf., PCE = 12.55% for the reference PV module with the bare PET) due to the mainly improved short circuit current from 49.35 to 52.01 mA, exhibiting the PCE increment percentage of ∼5.7%. For light incident angle-dependent PV module current-voltage characteristics, superior solar energy conversion properties are also obtained in a broad angle range of 10-80°.

  16. Hazards Caused by UV Rays of Xenon Light Based High Performance Solar Simulators.

    PubMed

    Dibowski, Gerd; Esser, Kai

    2017-09-01

    Solar furnaces are used worldwide to conduct experiments to demonstrate the feasibility of solar-chemical processes with the aid of concentrated sunlight, or to qualify high temperature-resistant components. In recent years, high-flux solar simulators (HFSSs) based on short-arc xenon lamps are more frequently used. The emitted spectrum is very similar to natural sunlight but with dangerous portions of ultraviolet light as well. Due to special benefits of solar simulators the increase of construction activity for HFSS can be observed worldwide. Hence, it is quite important to protect employees against serious injuries caused by ultraviolet radiation (UVR) in a range of 100 nm to 400 nm. The UV measurements were made at the German Aerospace Center (DLR), Cologne and Paul-Scherrer-Institute (PSI), Switzerland, during normal operations of the HFSS, with a high-precision UV-A/B radiometer using different experiment setups at different power levels. Thus, the measurement results represent UV emissions which are typical when operating a HFSS. Therefore, the biological effects on people exposed to UVR was investigated systematically to identify the existing hazard potential. It should be noted that the permissible workplace exposure limits for UV emissions significantly exceeded after a few seconds. One critical value was strongly exceeded by a factor of 770. The prevention of emissions must first and foremost be carried out by structural measures. Furthermore, unambiguous protocols have to be defined and compliance must be monitored. For short-term activities in the hazard area, measures for the protection of eyes and skin must be taken.

  17. Relating Structure to Efficiency in Surfactant-Free Polymer/Fullerene Nanoparticle-Based Organic Solar Cells.

    PubMed

    Gärtner, Stefan; Clulow, Andrew J; Howard, Ian A; Gilbert, Elliot P; Burn, Paul L; Gentle, Ian R; Colsmann, Alexander

    2017-12-13

    Nanoparticle dispersions open up an ecofriendly route toward printable organic solar cells. They can be formed from a variety of organic semiconductors by using miniemulsions that employ surfactants to stabilize the nanoparticles in dispersion and to prevent aggregation. However, whenever surfactant-based nanoparticle dispersions have been used to fabricate solar cells, the reported performances remain moderate. In contrast, solar cells from nanoparticle dispersions formed by precipitation (without surfactants) can exhibit power conversion efficiencies close to those of state-of-the-art solar cells processed from blend solutions using chlorinated solvents. In this work, we use small-angle neutron scattering measurements and transient absorption spectroscopy to investigate why surfactant-free nanoparticles give rise to efficient organic solar cells. We show that surfactant-free nanoparticles comprise a uniform distribution of small semiconductor domains, similar to that of bulk-heterojunction films formed using traditional solvent processing. This observation differs from surfactant-based miniemulsion nanoparticles that typically exhibit core-shell structures. Hence, the surfactant-free nanoparticles already possess the optimum morphology for efficient energy conversion before they are assembled into the photoactive layer of a solar cell. This structural property underpins the superior performance of the solar cells containing surfactant-free nanoparticles and is an important design criterion for future nanoparticle inks.

  18. Performance assessment of different day-of-the-year-based models for estimating global solar radiation - Case study: Egypt

    NASA Astrophysics Data System (ADS)

    Hassan, Gasser E.; Youssef, M. Elsayed; Ali, Mohamed A.; Mohamed, Zahraa E.; Shehata, Ali I.

    2016-11-01

    Different models are introduced to predict the daily global solar radiation in different locations but there is no specific model based on the day of the year is proposed for many locations around the world. In this study, more than 20 years of measured data for daily global solar radiation on a horizontal surface are used to develop and validate seven models to estimate the daily global solar radiation by day of the year for ten cities around Egypt as a case study. Moreover, the generalization capability for the best models is examined all over the country. The regression analysis is employed to calculate the coefficients of different suggested models. The statistical indicators namely, RMSE, MABE, MAPE, r and R2 are calculated to evaluate the performance of the developed models. Based on the validation with the available data, the results show that the hybrid sine and cosine wave model and 4th order polynomial model have the best performance among other suggested models. Consequently, these two models coupled with suitable coefficients can be used for estimating the daily global solar radiation on a horizontal surface for each city, and also for all the locations around the studied region. It is believed that the established models in this work are applicable and significant for quick estimation for the average daily global solar radiation on a horizontal surface with higher accuracy. The values of global solar radiation generated by this approach can be utilized in the design and estimation of the performance of different solar applications.

  19. Design, fabrication, and characterization of polymer based bulk heterojunction solar cells with enhanced efficiencies

    NASA Astrophysics Data System (ADS)

    Lu, Haiwei

    Polymer based bulk heterojunction (BHJ) solar cells offer promising technological advantages for actualization of low-cost and large-area fabrication on flexible substrates. To reach the envisaged market entry figure of 10% power conversion efficiency (PCE), it is crucial that more solar energy is utilized in the active layer, requiring both higher energy conversion efficiency and expansion of the absorption spectrum of the active layer to near infrared (NIR) region. The research introduced in this dissertation is an effort to increase PCE of solar cells from the aforementioned two directions. In the first method, carbon nanotubes (CNTs) were incorporated into polymer-fullerene BHJ solar cells to increase the hole-collection efficiency. Devices with CNT monolayer networks placed at different positions were fabricated, and the impact of CNTs on device performance was studied. It was demonstrated that CNTs placed on the hole-collection side of the device resulted in optimized performance, with PCE increased from 4% to 4.9%. To realize the controlled deposition of a uniform layer of CNTs on different positions, a mild plasma treatment of the active-layer was employed, and the influence of plasma treatment on device performance was also studied. In the second strategy, I developed an approach to expand the absorption spectrum to NIR region. In this case, hybrid polymer based BHJ solar cells composed of pyridine-capped PbS (PbS-py) quantum dots (QDs) and poly(3-hexylthiophene) (P3HT) were proposed. With pyridines as capping ligands, devices showed superior performance compared to with conventionally used oleate agents. PbS QDs with bandgaps of ˜1.13-1.38 eV offered the advantage of energetically favorable charge separation between P3HT and PbS QDs for photoexcitons in both visible and NIR regions. It was also found that thermal annealing leads to the removal of excess and interfacial pyridine ligands in polymer/QDs composites, and thus provides intimate electrical

  20. Evaluation of solar gain through skylights for inclusion in the SP53 residential building loads data base

    SciTech Connect

    Hanford, J.W.; Huang, Y.J.

    The energy performance of skylights is similar to that of windows in admitting solar heat gain, while at the same time providing a pathway for convective and conductive heat transfer through the building envelope. Since skylights are typically installed at angles ranging from 0{degrees} to 45{degrees}, and differ from windows in both their construction and operation, their conductive and convective heat gains or losses, as well as solar heat gain, will differ for the same rough opening and thermal characteristics. The objective of this work is to quantify the impact of solar gain through skylights on building heating and coolingmore » loads in 45 climates, and to develop a method for including these data into the SP53 residential loads data base previously developed by LBL in support of DOE`s Automated Residential Energy Standard (ARES) program. The authors used the DOE-2.1C program to simulate the heating and cooling loads of a prototypical residential building while varying the size and solar characteristics of skylights and windows. The results are presented as Skylight Solar Loads, which are the contribution of solar gains through skylights to the overall building heating and cooling loads, and as Skylight Solar Load Ratios, which are the ratios of skylight solar loads to those for windows with the same orientation. The study shows that skylight solar loads are larger than those for windows in both heating and cooling. Skylight solar cooling loads are from three to four times greater than those for windows regardless of the skylight tilt, except for those facing north. These cooling loads are largest for south-facing skylights at a tilt angle of approximately 20{degrees}, and drop off at higher tilts and other orientations.« less

  1. Bismuth Based Hybrid Perovskites A3Bi2 I9 (A: Methylammonium or Cesium) for Solar Cell Application.

    PubMed

    Park, Byung-Wook; Philippe, Bertrand; Zhang, Xiaoliang; Rensmo, Håkan; Boschloo, Gerrit; Johansson, Erik M J

    2015-11-18

    Low-toxic bismuth-based perovskites are prepared for the possible replacement of lead perovskite in solar cells. The perovskites have a hexagonal crystalline phase and light absorption in the visible region. A power conversion efficiency of over 1% is obtained for a solar cell with Cs3 Bi2 I9 perovskite, and it is concluded that bismuth perovskites have very promising properties for further development in solar cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Orbit dynamics and geographical coverage capabilities of satellite-based solar occultation experiments for global monitoring of stratospheric constituents

    NASA Technical Reports Server (NTRS)

    Brooks, D. R.

    1980-01-01

    Orbit dynamics of the solar occultation technique for satellite measurements of the Earth's atmosphere are described. A one-year mission is simulated and the orbit and mission design implications are discussed in detail. Geographical coverage capabilities are examined parametrically for a range of orbit conditions. The hypothetical mission is used to produce a simulated one-year data base of solar occultation measurements; each occultation event is assumed to produce a single number, or 'measurement' and some statistical properties of the data set are examined. A simple model is fitted to the data to demonstrate a procedure for examining global distributions of atmospheric constitutents with the solar occultation technique.

  3. H2O incorporation in the phosphorene/a-SiO2 interface: a first-principles study

    NASA Astrophysics Data System (ADS)

    Scopel, Wanderlã L.; Souza, Everson S.; Miwa, R. H.

    2017-02-01

    Based on first-principles calculations, we investigate (i) the energetic stability and electronic properties of single-layer phosphorene (SLP) adsorbed on an amorphous SiO2 surface (SLP/a-SiO2), and (ii) the further incorporation of water molecules at the phosphorene/a-SiO2 interface. In (i), we find that the phosphorene sheet binds to a-SiO2 through van der Waals interactions, even in the presence of oxygen vacancies on the surface. The SLP/a-SiO2 system presents a type-I band alignment, with the valence (conduction) band maximum (minimum) of the phosphorene lying within the energy gap of the a-SiO2 substrate. The structure and the surface-potential corrugations promote the formation of electron-rich and electron-poor regions on the phosphorene sheet and at the SLP/a-SiO2 interface. Such charge density puddles are strengthened by the presence of oxygen vacancies in a-SiO2. In (ii), because of the amorphous structure of the surface, we consider a number of plausible geometries for H2O embedded in the SLP/a-SiO2 interface. There is an energetic preference for the formation of hydroxyl (OH) groups on the a-SiO2 surface. Meanwhile, in the presence of oxygenated water or interstitial oxygen in the phosphorene sheet, we observe the formation of metastable OH bonded to the phosphorene, and the formation of energetically stable P-O-Si chemical bonds at the SLP/a-SiO2 interface. Further x-ray absorption spectra simulations are performed, which aim to provide additional structural/electronic information on the oxygen atoms forming hydroxyl groups or P-O-Si chemical bonds at the interface region.

  4. H2O incorporation in the phosphorene/a-SiO2 interface: a first-principles study.

    PubMed

    Scopel, Wanderlã L; Souza, Everson S; Miwa, R H

    2017-02-22

    Based on first-principles calculations, we investigate (i) the energetic stability and electronic properties of single-layer phosphorene (SLP) adsorbed on an amorphous SiO 2 surface (SLP/a-SiO 2 ), and (ii) the further incorporation of water molecules at the phosphorene/a-SiO 2 interface. In (i), we find that the phosphorene sheet binds to a-SiO 2 through van der Waals interactions, even in the presence of oxygen vacancies on the surface. The SLP/a-SiO 2 system presents a type-I band alignment, with the valence (conduction) band maximum (minimum) of the phosphorene lying within the energy gap of the a-SiO 2 substrate. The structure and the surface-potential corrugations promote the formation of electron-rich and electron-poor regions on the phosphorene sheet and at the SLP/a-SiO 2 interface. Such charge density puddles are strengthened by the presence of oxygen vacancies in a-SiO 2 . In (ii), because of the amorphous structure of the surface, we consider a number of plausible geometries for H 2 O embedded in the SLP/a-SiO 2 interface. There is an energetic preference for the formation of hydroxyl (OH) groups on the a-SiO 2 surface. Meanwhile, in the presence of oxygenated water or interstitial oxygen in the phosphorene sheet, we observe the formation of metastable OH bonded to the phosphorene, and the formation of energetically stable P-O-Si chemical bonds at the SLP/a-SiO 2 interface. Further x-ray absorption spectra simulations are performed, which aim to provide additional structural/electronic information on the oxygen atoms forming hydroxyl groups or P-O-Si chemical bonds at the interface region.

  5. Research and development of CdTe based thin film PV solar cells

    NASA Astrophysics Data System (ADS)

    Diso, Dahiru Garba

    The motivation behind this research is to bring cheap, low-cost and clean energy technologies to the society. Colossal use of fossil fuel has created noticeable pollution problems contributing to climate change and health hazards. Silicon based solar cells have dominated the market but it is cost is high due to the manufacturing process. Therefore, the way forward is to develop thin films solar cells using low-cost attractive materials, grown by cheaper, scalable and manufacturable techniques.The aim and objectives of this work is to develop low-cost, high efficiency solar cell using electrodeposition (ED) technique. The material layers include CdS and ZnTe as the window materials, while the absorber material is CdTe. Fabricating a suitable devices for solar energy conversion (i.e. glass/conducting glass/window material/absorber material/metal) structure. Traditional way of fabricating this structure is to grow window material (CdS) using chemical bath deposition (CBD) and absorber material (CdTe) using electrodeposition. However, CBD is a batch process and therefore creates large volumes of Cd-containing waste solutions each time adding high cost in manufacturing process. This research programme is therefore on development of an "All ED-solar cells" structure.Material studies were carried out using photoelectrochemical (PEC) studies, UV-Vis spectrophotometry, X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Furthermore, the electrical characterisation of fully fabricated devices was performed using current-voltage (I-V) and capacitance-voltage (C-V) measurements.This research programme has demonstrated that CdS and ZnTe window materials can be electrodeposited and used in thin film solar cell devices. The CdS electrolytic bath can be used for a period of 7 months without discarding it like in the CBD process which usually has life

  6. Advanced Deployable Shell-Based Composite Booms for Small Satellite Structural Applications Including Solar Sails

    NASA Technical Reports Server (NTRS)

    Fernandez, Juan M.

    2017-01-01

    State of the art deployable structures are mainly being designed for medium to large size satellites. The lack of reliable deployable structural systems for low cost, small volume, rideshare-class spacecraft severely constrains the potential for using small satellite platforms for affordable deep space science and exploration precursor missions that could be realized with solar sails. There is thus a need for reliable, lightweight, high packaging efficiency deployable booms that can serve as the supporting structure for a wide range of small satellite systems including solar sails for propulsion. The National Air and Space Administration (NASA) is currently investing in the development of a new class of advanced deployable shell-based composite booms to support future deep space small satellite missions using solar sails. The concepts are being designed to: meet the unique requirements of small satellites, maximize ground testability, permit the use of low-cost manufacturing processes that will benefit scalability, be scalable for use as elements of hierarchical structures (e.g. trusses), allow long duration storage, have high deployment reliability, and have controlled deployment behavior and predictable deployed dynamics. This paper will present the various rollable boom concepts that are being developed for 5-20 m class size deployable structures that include solar sails with the so-called High Strain Composites (HSC) materials. The deployable composite booms to be presented are being developed to expand the portfolio of available rollable booms for small satellites and maximize their length for a given packaged volume. Given that solar sails are a great example of volume and mass optimization, the booms were designed to comply with nominal solar sail system requirements for 6U CubeSats, which are a good compromise between those of smaller form factors (1U, 2U and 3U CubeSats) and larger ones (12 U and 27 U future CubeSats, and ESPA-class microsatellites). Solar

  7. Theory of the high base resistivity n(+)pp(+) silicon solar cell and its application to radiation damage effects

    NASA Technical Reports Server (NTRS)

    Goradia, C.; Weinberg, I.

    1985-01-01

    Particulate radiation in space is a principal source of silicon solar cell degradation, and an investigation of cell radiation damage at higher base resistivities appears to have implication toward increasing solar cell and, therefore, useful satellite lifetimes in the space environment. However, contrary to expectations, it has been found that for cells with resistivities of 84 and 1250 ohm cm, the radiation resistance decreases as cell base resistivity increases. An analytical solar-cell computer model was developed with the objective to determine the reasons for this unexpected behavior. The present paper has the aim to describe the analytical model and its use in interpreting the behavior, under irradiation, of high-resistivity solar cells. Attention is given to boundary conditions at the space-charge region edges, cell currents, cell voltages, the generation of the theoretical I-V characteristic, experimental results, and computer calculations.

  8. Solar-thermal complex sample processing for nucleic acid based diagnostics in limited resource settings

    PubMed Central

    Gumus, Abdurrahman; Ahsan, Syed; Dogan, Belgin; Jiang, Li; Snodgrass, Ryan; Gardner, Andrea; Lu, Zhengda; Simpson, Kenneth; Erickson, David

    2016-01-01

    The use of point-of-care (POC) devices in limited resource settings where access to commonly used infrastructure, such as water and electricity, can be restricted represents simultaneously one of the best application fits for POC systems as well as one of the most challenging places to deploy them. Of the many challenges involved in these systems, the preparation and processing of complex samples like stool, vomit, and biopsies are particularly difficult due to the high number and varied nature of mechanical and chemical interferents present in the sample. Previously we have demonstrated the ability to use solar-thermal energy to perform PCR based nucleic acid amplifications. In this work demonstrate how the technique, using similar infrastructure, can also be used to perform solar-thermal based sample processing system for extracting and isolating Vibrio Cholerae nucleic acids from fecal samples. The use of opto-thermal energy enables the use of sunlight to drive thermal lysing reactions in large volumes without the need for external electrical power. Using the system demonstrate the ability to reach a 95°C threshold in less than 5 minutes and maintain a stable sample temperature of +/− 2°C following the ramp up. The system is demonstrated to provide linear results between 104 and 108 CFU/mL when the released nucleic acids were quantified via traditional means. Additionally, we couple the sample processing unit with our previously demonstrated solar-thermal PCR and tablet based detection system to demonstrate very low power sample-in-answer-out detection. PMID:27231636

  9. Space Based Observations of Coronal Cavities in Conjunction with the Total Solar Eclipse of July 2010

    NASA Technical Reports Server (NTRS)

    Kucera, T. A.; Berger, T. E.; Druckmuller, M.; Dietzel, M.; Gibson, S. E.; Habbal, S. R.; Morgan, H.; Reeves, K. K.; Schmit, D. J.; Seaton, D. B.

    2010-01-01

    In conjunction with the total solar eclipse on July 11, 2010 we coordinated a campaign between ground and space based observations. Our specific goal was to augment the ground based measurement of corona) prominence cavity temperatures made using iron lines in the IR (Habbal et al. 2010 ApJ 719 1362) with measurements performed by space based instruments. Included in the campaign were Hinode/EIS, XRT and SOT, PROBA2/SWAP, SDO/AIA, SOHO/CDS and STEREO/SECCHI/EUVI, in addition to the ground based IR measurements. We plan to use a combination of line ratio and forward modeling techniques to investigate the density and temperature structure of the cavities at that time.

  10. Lewis Acid-Base Adduct Approach for High Efficiency Perovskite Solar Cells.

    PubMed

    Lee, Jin-Wook; Kim, Hui-Seon; Park, Nam-Gyu

    2016-02-16

    Since the first report on the long-term durable 9.7% solid-state perovskite solar cell employing methylammonium lead iodide (CH3NH3PbI3), mesoporous TiO2, and 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (spiro-MeOTAD) in 2012, following the seed technologies on perovskite-sensitized liquid junction solar cells in 2009 and 2011, a surge of interest has been focused on perovskite solar cells due to superb photovoltaic performance and extremely facile fabrication processes. The power conversion efficiency (PCE) of perovskite solar cells reached 21% in a very short period of time. Such an unprecedentedly high photovoltaic performance is due to the intrinsic optoelectronic property of organolead iodide perovskite material. Moreover, a high dielectric constant, sub-millimeter scale carrier diffusion length, an underlying ferroelectric property, and ion migration behavior can make organolead halide perovskites suitable for multifunctionality. Thus, besides solar cell applications, perovskite material has recently been applied to a variety fields of materials science such as photodetectors, light emitting diodes, lasing, X-ray imaging, resistive memory, and water splitting. Regardless of application areas, the growth of a well-defined perovskite layer with high crystallinity is essential for effective utilization of its excellent physicochemical properties. Therefore, an effective methodology for preparation of high quality perovskite layers is required. In this Account, an effective methodology for production of high quality perovskite layers is described, which is the Lewis acid-base adduct approach. In the solution process to form the perovskite layer, the key chemicals of CH3NH3I (or HC(NH2)2I) and PbI2 are used by dissolving them in polar aprotic solvents. Since polar aprotic solvents bear oxygen, sulfur, or nitrogen, they can act as a Lewis base. In addition, the main group compound PbI2 is known to be a Lewis acid. Thus, PbI2 has a chance

  11. CH3NH3PbI3 based solar cell: Modified by antisolvent treatment

    NASA Astrophysics Data System (ADS)

    Nandi, Pronoy; Giri, Chandan; Bansode, Umesh; Topwal, D.

    2017-05-01

    Solar cells based on new class of organic inorganic hybrid perovskite CH3NH3PbI3 were prepared by Ethyl acetate (EA); antisolvent treatment for the first time. This treatment results in new morphology for CH3NH3PbI3 thin film. FESEM image shows microrod type structures of CH3NH3PbI3 after EA antisolvent treatment. Energy band diagram was constructed using photoluminescence and photoemission studies. A better power conversion efficiency was achieved in EA treated film compare to without EA treated film.

  12. PCDTBT based solar cells: one year of operation under real-world conditions

    PubMed Central

    Zhang, Yiwei; Bovill, Edward; Kingsley, James; Buckley, Alastair R.; Yi, Hunan; Iraqi, Ahmed; Wang, Tao; Lidzey, David G.

    2016-01-01

    We present measurements of the outdoor stability of PCDTBT:PC71BM based bulk heterojunction organic solar cells for over the course of a year. We find that the devices undergo a burn-in process lasting 450 hours followed by a TS80 lifetime of up to 6200 hours. We conclude that in the most stable devices, the observed TS80 lifetime is limited by thermally-induced stress between the device layers, as well as materials degradation as a result of edge-ingress of water or moisture through the encapsulation. PMID:26857950

  13. Is light-induced degradation of a-Si:H/c-Si interfaces reversible?

    SciTech Connect

    El Mhamdi, El Mahdi; Holovsky, Jakub; Demaurex, Bénédicte

    2014-06-23

    Thin hydrogenated amorphous silicon (a-Si:H) films deposited on crystalline silicon (c-Si) surfaces are sensitive probes for the bulk electronic properties of a-Si:H. Here, we use such samples during repeated low-temperature annealing and visible-light soaking to investigate the long-term stability of a-Si:H films. We observe that during annealing the electronic improvement of the interfaces follows stretched exponentials as long as hydrogen evolution in the films can be detected. Once such evolution is no longer observed, the electronic improvement occurs much faster. Based on these findings, we discuss how the reversibility of light-induced defects depends on (the lack of observable) hydrogen evolution.

  14. Fabrication and characterization of P3HT:PCBM-based thin film organic solar cells with zinc phthalocyanine

    SciTech Connect

    Maruhashi, Haruto, E-mail: oku@mat.usp.ac.jp; Oku, Takeo, E-mail: oku@mat.usp.ac.jp; Suzuki, Atsushi, E-mail: oku@mat.usp.ac.jp

    2015-02-27

    [6,6]–phenyl C{sub 61}–butyric acid methyl ester and poly(3–hexylthiophene) bulk heterojunction solar cells added with zinc–tetra–tertiary–butyl–phthalocyanine (ZnPc) were fabricated and characterized. The photovoltaic properties of the solar cells with an inverted structure were improved by the ZnPc addition, which were investigated on the bases of current density–voltage characteristics, incident photon to current conversion efficiency.

  15. Ternary Polymer Solar Cells based on Two Acceptors and One Donor for Achieving 12.2% Efficiency.

    PubMed

    Zhao, Wenchao; Li, Sunsun; Zhang, Shaoqing; Liu, Xiaoyu; Hou, Jianhui

    2017-01-01

    Ternary polymer solar cells are fabricated based on one donor PBDB-T and two acceptors (a methyl-modified small-molecular acceptor (IT-M) and a bis-adduct of Bis[70]PCBM). A high power conversion efficiency of 12.2% can be achieved. The photovoltaic performance of the ternary polymer solar cells is not sensitive to the composition of the blend. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Plasma-initiated rehydrogenation of amorphous silicon to increase the temperature processing window of silicon heterojunction solar cells

    SciTech Connect

    Shi, Jianwei; Boccard, Mathieu; Holman, Zachary

    The dehydrogenation of intrinsic hydrogenated amorphous silicon (a-Si:H) at temperatures above approximately 300°C degrades its ability to passivate silicon wafer surfaces. This limits the temperature of post-passivation processing steps during the fabrication of advanced silicon heterojunction or silicon-based tandem solar cells. We demonstrate that a hydrogen plasma can rehydrogenate intrinsic a-Si:H passivation layers that have been dehydrogenated by annealing. The hydrogen plasma treatment fully restores the effective carrier lifetime to several milliseconds in textured crystalline siliconwafers coated with 8-nm-thick intrinsic a-Si:H layers after annealing at temperatures of up to 450°C. Plasma-initiated rehydrogenation also translates to complete solar cells: A silicon heterojunction solar cell subjected to annealing at 450°C (following intrinsic a-Si:H deposition) had an open-circuit voltage of less than 600 mV, but an identical cell that received hydrogen plasma treatment reached a voltagemore » of over 710 mV and an efficiency of over 19%.« less

  17. Plasma-initiated rehydrogenation of amorphous silicon to increase the temperature processing window of silicon heterojunction solar cells

    DOE PAGES

    Shi, Jianwei; Boccard, Mathieu; Holman, Zachary

    2016-07-19

    The dehydrogenation of intrinsic hydrogenated amorphous silicon (a-Si:H) at temperatures above approximately 300°C degrades its ability to passivate silicon wafer surfaces. This limits the temperature of post-passivation processing steps during the fabrication of advanced silicon heterojunction or silicon-based tandem solar cells. We demonstrate that a hydrogen plasma can rehydrogenate intrinsic a-Si:H passivation layers that have been dehydrogenated by annealing. The hydrogen plasma treatment fully restores the effective carrier lifetime to several milliseconds in textured crystalline siliconwafers coated with 8-nm-thick intrinsic a-Si:H layers after annealing at temperatures of up to 450°C. Plasma-initiated rehydrogenation also translates to complete solar cells: A silicon heterojunction solar cell subjected to annealing at 450°C (following intrinsic a-Si:H deposition) had an open-circuit voltage of less than 600 mV, but an identical cell that received hydrogen plasma treatment reached a voltagemore » of over 710 mV and an efficiency of over 19%.« less

  18. THERMODYNAMIC SPECTRUM OF SOLAR FLARES BASED ON SDO/EVE OBSERVATIONS: TECHNIQUES AND FIRST RESULTS

    SciTech Connect

    Wang, Yuming; Zhou, Zhenjun; Liu, Kai

    2016-03-15

    The Solar Dynamics Observatory (SDO)/EUV Variability Experiment (EVE) provides rich information on the thermodynamic processes of solar activities, particularly on solar flares. Here, we develop a method to construct thermodynamic spectrum (TDS) charts based on the EVE spectral lines. This tool could potentially be useful for extreme ultraviolet (EUV) astronomy to learn about the eruptive activities on distant astronomical objects. Through several cases, we illustrate what we can learn from the TDS charts. Furthermore, we apply the TDS method to 74 flares equal to or greater than the M5.0 class, and reach the following statistical results. First, EUV peaks are always behind the soft X-raymore » (SXR) peaks and stronger flares tend to have faster cooling rates. There is a power-law correlation between the peak delay times and the cooling rates, suggesting a coherent cooling process of flares from SXR to EUV emissions. Second, there are two distinct temperature drift patterns, called Type I and Type II. For Type I flares, the enhanced emission drifts from high to low temperature like a quadrilateral, whereas for Type II flares the drift pattern looks like a triangle. Statistical analysis suggests that Type II flares are more impulsive than Type I flares. Third, for late-phase flares, the peak intensity ratio of the late phase to the main phase is roughly correlated with the flare class, and the flares with a strong late phase are all confined. We believe that the re-deposition of the energy carried by a flux rope, which unsuccessfully erupts out, into thermal emissions is responsible for the strong late phase found in a confined flare. Furthermore, we show the signatures of the flare thermodynamic process in the chromosphere and transition region in the TDS charts. These results provide new clues to advance our understanding of the thermodynamic processes of solar flares and associated solar eruptions, e.g., coronal mass ejections.« less

  19. Six Sigma-based approach to optimise the diffusion process of crystalline silicon solar cell manufacturing

    NASA Astrophysics Data System (ADS)

    Prasad, A. Guru; Saravanan, S.; Gijo, E. V.; Dasari, Sreenivasa Murty; Tatachar, Raghu; Suratkar, Prakash

    2016-02-01

    Silicon-based photovoltaics (PV) plays the dominant role in the history of PV due to the continuous process and technology improvement in silicon solar cells and its manufacturing flow. In general, silicon solar cell process uses either p-type- or n-type-doped silicon as the starting material. Currently, most of the PV industries use p-type, boron-doped silicon wafer as the starting material. In this work too, the boron-doped wafers were considered as the starting material to create pn junction and phosphorus was used as n-type doping material. Industries use either phosphorous oxy chloride (POCl3) or ortho phosphoric acid (H3PO4) as the precursor for doping phosphorous. While the industries use POCl3 as the precursor, the throughput is lesser than that of the industries' use of H3PO4 due to the manufacturing limitations of the POCl3-based equipments. Hence, in order to achieve the operational excellence in POCl3-based equipments, business strategies such as the Six Sigma methodology have to be adapted. This paper describes the application of Six Sigma Define-Measure-Analyze-Improve-Control methodology for throughput improvement of the phosphorus doping process. The optimised recipe has been implemented in the production and it is running successfully. As a result of this project, an effective gain of 0.9 MW was reported per annum.

  20. Perfluoro anion based binary and ternary ionic liquids as electrolytes for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Lin, Hsi-Hsin; Peng, Jia-De; Suryanarayanan, V.; Velayutham, D.; Ho, Kuo-Chuan

    2016-04-01

    In this work, eight new ionic liquids (ILs) based on triethylammonium (TEA) or n-methylpiperidinium (NMP) cations and perfluoro carboxylate (PFC) anions having different carbon chain lengths are synthesized and their physico-chemical properties such as density, decomposition temperature, viscosity and conductivity are determined. Photovoltaic characteristics of dye-sensitized solar cells (DSSCs) with binary ionic liquids electrolytes, containing the mixture of the synthesized ILs and 1-methyl-3-propyl imidazolium iodide (PMII) (v/v = 35/65), are evaluated. Among the different ILs, solar cells containing NMP based ILs show higher VOC than that of TEA, whereas, higher JSC is noted for the DSSCs incorporated with the latter when compared to the former. Further, the photo-current of the DSSCs decreases with the increase of the carbon chain length of perfluoro carboxylate anionic group of ILs. The cell performance of the DSSC containing ternary ionic liquids-based electrolytes compose of NMP-2C/TEA-2C/PMII (v/v/v = 28/7/65) exhibits a JSC of 12.99 mA cm-2, a VOC of 639.0 mV, a FF of 0.72, and a cell efficiency of 6.01%. The extraordinary durability of the DSSC containing the above combination of electrolytes stored in dark at 50 °C is proved to be unfailing up to 1200 h.

  1. High-Efficiency Small Molecule-Based Bulk-Heterojunction Solar Cells Enhanced by Additive Annealing.

    PubMed

    Li, Lisheng; Xiao, Liangang; Qin, Hongmei; Gao, Ke; Peng, Junbiao; Cao, Yong; Liu, Feng; Russell, Thomas P; Peng, Xiaobin

    2015-09-30

    Solvent additive processing is important in optimizing an active layer's morphology and thus improving the performance of organic solar cells (OSCs). In this study, we find that how 1,8-diiodooctane (DIO) additive is removed plays a critical role in determining the film morphology of the bulk heterojunction OSCs in inverted structure based on a porphyrin small molecule. Different from the cases reported for polymer-based OSCs in conventional structures, the inverted OSCs upon the quick removal of the additive either by quick vacuuming or methanol washing exhibit poorer performance. In contrast, the devices after keeping the active layers in ambient pressure with additive dwelling for about 1 h (namely, additive annealing) show an enhanced power conversion efficiency up to 7.78% with a large short circuit current of 19.25 mA/cm(2), which are among the best in small molecule-based solar cells. The detailed morphology analyses using UV-vis absorption spectroscopy, grazing incidence X-ray diffraction, resonant soft X-ray scattering, and atomic force microscopy demonstrate that the active layer shows smaller-sized phase separation but improved structure order upon additive annealing. On the contrary, the quick removal of the additive either by quick vacuuming or methanol washing keeps the active layers in an earlier stage of large scaled phase separation.

  2. Polymer-based chromophore-catalyst assemblies for solar energy conversion

    NASA Astrophysics Data System (ADS)

    Leem, Gyu; Sherman, Benjamin D.; Schanze, Kirk S.

    2017-12-01

    The synthesis of polymer-based assemblies for light harvesting has been motivated by the multi-chromophore antennas that play a role in natural photosynthesis for the potential use in solar conversion technologies. This review describes a general strategy for using polymer-based chromophore-catalyst assemblies for solar-driven water oxidation at a photoanode in a dye-sensitized photoelectrochemical cell (DSPEC). This report begins with a summary of the synthetic methods and fundamental photophysical studies of light harvesting polychormophores in solution which show these materials can transport excited state energy to an acceptor where charge-separation can occur. In addition, studies describing light harvesting polychromophores containing an anchoring moiety (ionic carboxylate) for covalent bounding to wide band gap mesoporous semiconductor surfaces are summarized to understand the photophysical mechanisms of directional energy flow at the interface. Finally, the performance of polychromophore/catalyst assembly-based photoanodes capable of light-driven water splitting to oxygen and hydrogen in a DSPEC are summarized.

  3. Polymer-based chromophore-catalyst assemblies for solar energy conversion.

    PubMed

    Leem, Gyu; Sherman, Benjamin D; Schanze, Kirk S

    2017-01-01

    The synthesis of polymer-based assemblies for light harvesting has been motivated by the multi-chromophore antennas that play a role in natural photosynthesis for the potential use in solar conversion technologies. This review describes a general strategy for using polymer-based chromophore-catalyst assemblies for solar-driven water oxidation at a photoanode in a dye-sensitized photoelectrochemical cell (DSPEC). This report begins with a summary of the synthetic methods and fundamental photophysical studies of light harvesting polychormophores in solution which show these materials can transport excited state energy to an acceptor where charge-separation can occur. In addition, studies describing light harvesting polychromophores containing an anchoring moiety (ionic carboxylate) for covalent bounding to wide band gap mesoporous semiconductor surfaces are summarized to understand the photophysical mechanisms of directional energy flow at the interface. Finally, the performance of polychromophore/catalyst assembly-based photoanodes capable of light-driven water splitting to oxygen and hydrogen in a DSPEC are summarized.

  4. Photostability of low cost dye-sensitized solar cells based on natural and synthetic dyes

    NASA Astrophysics Data System (ADS)

    Abdou, E. M.; Hafez, H. S.; Bakir, E.; Abdel-Mottaleb, M. S. A.

    2013-11-01

    This paper deals with the use of some natural pigments as well as synthetic dyes to act as sensitizers in dye-sensitized solar cells (DSSCs). Anthocyanin dye extracted from rosella (Hibiscus sabdariffa L.) flowers, the commercially available textile dye Remazole Red RB-133 (RR) and merocyanin-like dye based on 7-methyl coumarin are tested. The photostability of the three dyes is investigated under UV-Vis light exposure. The results show a relatively high stability of the three dyes. Moreover, the photostability of the solid dyes is studied over the TiO2 film electrodes. A very low decolorization rates are recorded as; rate constants k = 1.6, 2.1 and 1.9 × 10-3 min-1 for anthocyanin, RR and coumarin dyes, respectively. The stability results favor selecting anthocyanin as a promising sensitizer candidate in DSSCs based on natural products. Dyes-sensitized solar cells are fabricated and their conversion efficiency (η) is 0.27%, 0.14% and 0.001% for the anthocyanin, RR and coumarin dyes, respectively. Moreover, stability tests of the sealed cells based on anthocyanin and RR dyes are done under continuous light exposure of 100 mW cm-2, reveals highly stable DSSCs.

  5. An evolutionary computation based algorithm for calculating solar differential rotation by automatic tracking of coronal bright points

    NASA Astrophysics Data System (ADS)

    Shahamatnia, Ehsan; Dorotovič, Ivan; Fonseca, Jose M.; Ribeiro, Rita A.

    2016-03-01

    Developing specialized software tools is essential to support studies of solar activity evolution. With new space missions such as Solar Dynamics Observatory (SDO), solar images are being produced in unprecedented volumes. To capitalize on that huge data availability, the scientific community needs a new generation of software tools for automatic and efficient data processing. In this paper a prototype of a modular framework for solar feature detection, characterization, and tracking is presented. To develop an efficient system capable of automatic solar feature tracking and measuring, a hybrid approach combining specialized image processing, evolutionary optimization, and soft computing algorithms is being followed. The specialized hybrid algorithm for tracking solar features allows automatic feature tracking while gathering characterization details about the tracked features. The hybrid algorithm takes advantages of the snake model, a specialized image processing algorithm widely used in applications such as boundary delineation, image segmentation, and object tracking. Further, it exploits the flexibility and efficiency of Particle Swarm Optimization (PSO), a stochastic population based optimization algorithm. PSO has been used successfully in a wide range of applications including combinatorial optimization, control, clustering, robotics, scheduling, and image processing and video analysis applications. The proposed tool, denoted PSO-Snake model, was already successfully tested in other works for tracking sunspots and coronal bright points. In this work, we discuss the application of the PSO-Snake algorithm for calculating the sidereal rotational angular velocity of the solar corona. To validate the results we compare them with published manual results performed by an expert.

  6. Chlorine-Incorporation-Induced Formation of the Layered Phase for Antimony-Based Lead-Free Perovskite Solar Cells.

    PubMed

    Jiang, Fangyuan; Yang, Dongwen; Jiang, Youyu; Liu, Tiefeng; Zhao, Xingang; Ming, Yue; Luo, Bangwu; Qin, Fei; Fan, Jiacheng; Han, Hongwei; Zhang, Lijun; Zhou, Yinhua

    2018-01-24

    The environmental toxicity of Pb in organic-inorganic hybrid perovskite solar cells remains an issue, which has triggered intense research on seeking alternative Pb-free perovskites for solar applications. Halide perovskites based on group-VA cations of Bi 3+ and Sb 3+ with the same lone-pair ns 2 state as Pb 2+ are promising candidates. Herein, through a joint experimental and theoretical study, we demonstrate that Cl-incorporated methylammonium Sb halide perovskites (CH 3 NH 3 ) 3 Sb 2 Cl X I 9-X show promise as efficient solar absorbers for Pb-free perovskite solar cells. Inclusion of methylammonium chloride into the precursor solutions suppresses the formation of the undesired zero-dimensional dimer phase and leads to the successful synthesis of high-quality perovskite films composed of the two-dimensional layered phase favored for photovoltaics. Solar cells based on the as-obtained (CH 3 NH 3 ) 3 Sb 2 Cl X I 9-X films reach a record-high power conversion efficiency over 2%. This finding offers a new perspective for the development of nontoxic and low-cost Sb-based perovskite solar cells.

  7. Evaluating the spatio-temporal performance of sky-imager-based solar irradiance analysis and forecasts

    NASA Astrophysics Data System (ADS)

    Schmidt, Thomas; Kalisch, John; Lorenz, Elke; Heinemann, Detlev

    2016-03-01

    Clouds are the dominant source of small-scale variability in surface solar radiation and uncertainty in its prediction. However, the increasing share of solar energy in the worldwide electric power supply increases the need for accurate solar radiation forecasts. In this work, we present results of a very short term global horizontal irradiance (GHI) forecast experiment based on hemispheric sky images. A 2-month data set with images from one sky imager and high-resolution GHI measurements from 99 pyranometers distributed over 10 km by 12 km is used for validation. We developed a multi-step model and processed GHI forecasts up to 25 min with an update interval of 15 s. A cloud type classification is used to separate the time series into different cloud scenarios. Overall, the sky-imager-based forecasts do not outperform the reference persistence forecasts. Nevertheless, we find that analysis and forecast performance depends strongly on the predominant cloud conditions. Especially convective type clouds lead to high temporal and spatial GHI variability. For cumulus cloud conditions, the analysis error is found to be lower than that introduced by a single pyranometer if it is used representatively for the whole area in distances from the camera larger than 1-2 km. Moreover, forecast skill is much higher for these conditions compared to overcast or clear sky situations causing low GHI variability, which is easier to predict by persistence. In order to generalize the cloud-induced forecast error, we identify a variability threshold indicating conditions with positive forecast skill.

  8. Spatio-temporal representativeness of ground-based downward solar radiation measurements

    NASA Astrophysics Data System (ADS)

    Schwarz, Matthias; Wild, Martin; Folini, Doris

    2017-04-01

    Surface solar radiation (SSR) is most directly observed with ground based pyranometer measurements. Besides measurement uncertainties, which arise from the pyranometer instrument itself, also errors attributed to the limited spatial representativeness of observations from single sites for their large-scale surrounding have to be taken into account when using such measurements for energy balance studies. In this study the spatial representativeness of 157 homogeneous European downward surface solar radiation time series from the Global Energy Balance Archive (GEBA) and the Baseline Surface Radiation Network (BSRN) were examined for the period 1983-2015 by using the high resolution (0.05°) surface solar radiation data set from the Satellite Application Facility on Climate Monitoring (CM-SAF SARAH) as a proxy for the spatiotemporal variability of SSR. By correlating deseasonalized monthly SSR time series form surface observations against single collocated satellite derived SSR time series, a mean spatial correlation pattern was calculated and validated against purely observational based patterns. Generally decreasing correlations with increasing distance from station, with high correlations (R2 = 0.7) in proximity to the observational sites (±0.5°), was found. When correlating surface observations against time series from spatially averaged satellite derived SSR data (and thereby simulating coarser and coarser grids), very high correspondence between sites and the collocated pixels has been found for pixel sizes up to several degrees. Moreover, special focus was put on the quantification of errors which arise in conjunction to spatial sampling when estimating the temporal variability and trends for a larger region from a single surface observation site. For 15-year trends on a 1° grid, errors due to spatial sampling in the order of half of the measurement uncertainty for monthly mean values were found.

  9. InGaP-based quantum well solar cells: Growth, structural design, and photovoltaic properties

    SciTech Connect

    Hashem, Islam E.; Zachary Carlin, C.; Hagar, Brandon G.

    2016-03-07

    Raising the efficiency ceiling of multi-junction solar cells (MJSCs) through the use of more optimal band gap configurations of next-generation MJSC is crucial for concentrator and space systems. Towards this goal, we propose two strain balanced multiple quantum well (SBMQW) structures to tune the bandgap of InGaP-based solar cells. These structures are based on In{sub x}Ga{sub 1−x}As{sub 1−z}P{sub z}/In{sub y}Ga{sub 1−y}P (x > y) and In{sub x}Ga{sub 1−x}P/In{sub y}Ga{sub 1−y}P (x > y) well/barrier combinations, lattice matched to GaAs in a p-i-n solar cell device. The bandgap of In{sub x}Ga{sub 1−x}As{sub 1−z}P{sub z}/In{sub y}Ga{sub 1−y}P can be tuned from 1.82 to 1.65 eV by adjustingmore » the well composition and thickness, which promotes its use as an efficient subcell for next generation five and six junction photovoltaic devices. The thicknesses of wells and barriers are adjusted using a zero net stress balance model to prevent the formation of defects. Thin layers of InGaAsP wells have been grown thermodynamically stable with compositions within the miscibility gap for the bulk alloy. The growth conditions of the two SBMQWs and the individual layers are reported. The structures are characterized and analyzed by optical microscopy, X-ray diffraction, photoluminescence, current-voltage characteristics, and spectral response (external quantum efficiency). The effect of the well number on the excitonic absorption of InGaAsP/InGaP SBMQWs is discussed and analyzed.« less

  10. Improved conversion efficiency of amorphous Si solar cells using a mesoporous ZnO pattern

    PubMed Central

    2014-01-01

    To provide a front transparent electrode for use in highly efficient hydrogenated amorphous silicon (a-Si:H) thin-film solar cells, porous flat layer and micro-patterns of zinc oxide (ZnO) nanoparticle (NP) layers were prepared through ultraviolet nanoimprint lithography (UV-NIL) and deposited on Al-doped ZnO (AZO) layers. Through this, it was found that a porous micro-pattern of ZnO NPs dispersed in resin can optimize the light-trapping pattern, with the efficiency of solar cells based on patterned or flat mesoporous ZnO layers increased by 27% and 12%, respectively. PMID:25276101

  11. CVD-Based Valence-Mending Passivation for Crystalline-Si Solar Cells

    SciTech Connect

    Tao, Meng

    2015-03-01

    The objective of this project is to investigate a new surface passivation technique, valence-mending passivation, for its applications in crystalline-Si solar cells to achieve significant efficiency improvement and cost reduction. As the enabling technique, the project includes the development of chemical vapor deposition recipes to passivate textured Si(100) and multicrystalline-Si surfaces by sulfur and the characterization of the passivated Si surfaces, including thermal stability, Schottky barrier height, contact resistance and surface recombination. One important application is to replace the Ag finger electrode in Si cells with Al to reduce cost, by ~$0.1/Wp, and allow terawatt-scale deployment of crystalline-Si solar cells.more » These all-Al Si cells require a low-temperature metallization process for the Al electrode, to be compatible with valence-mending passivation and to prevent Al diffusion into n-type Si. Another application is to explore valence-mending passivation of grain boundaries in multicrystalline Si by diffusing sulfur into grain boundaries, to reduce the efficiency gas between monocrystalline-Si solar cells and multicrystalline-Si cells. The major accomplishments of this project include: 1) Demonstration of chemical vapor deposition processes for valence-mending passivation of both monocrystalline Si(100) and multicrystalline Si surfaces. Record Schottky barriers have been demonstrated, with the new record-low barrier of less than 0.08 eV between Al and sulfur-passivated n-type Si(100) and the new record-high barrier of 1.14 eV between Al and sulfur-passivated p-type Si(100). On the textured p-type monocrystalline Si(100) surface, the highest barrier with Al is 0.85 eV by valence-mending passivation. 2) Demonstration of a low-temperature metallization process for Al in crystalline-Si solar cells. The new metallization process is based on electroplating of Al in a room-temperature ionic liquid. The resistivity of the electroplated Al is ~7

  12. Evaluation of in-situ thermal energy storage for lunar based solar dynamic systems

    NASA Technical Reports Server (NTRS)

    Crane, Roger A.

    1991-01-01

    A practical lunar based thermal energy storage system, based on locally available materials, could significantly reduce transportation requirements and associated costs of a continuous, solar derived power system. The concept reported here is based on a unique, in-situ approach to thermal energy storage. The proposed design is examined to assess the problems of start-up and the requirements for attainment of stable operation. The design remains, at this stage, partially conceptional in nature, but certain aspects of the design, bearing directly on feasibility, are examined in some detail. Specifically included is an engineering evaluation of the projected thermal performance of this system. Both steady state and start-up power requirements are evaluated and the associated thermal losses are evaluated as a basis for establishing potential system performance.

  13. Total internal reflection-based planar waveguide solar concentrator with symmetric air prisms as couplers.

    PubMed

    Xie, Peng; Lin, Huichuan; Liu, Yong; Li, Baojun

    2014-10-20

    We present a waveguide coupling approach for planar waveguide solar concentrator. In this approach, total internal reflection (TIR)-based symmetric air prisms are used as couplers to increase the coupler reflectivity and to maximize the optical efficiency. The proposed concentrator consists of a line focusing cylindrical lens array over a planar waveguide. The TIR-based couplers are located at the focal line of each lens to couple the focused sunlight into the waveguide. The optical system was modeled and simulated with a commercial ray tracing software (Zemax). Results show that the system used with optimized TIR-based couplers can achieve 70% optical efficiency at 50 × geometrical concentration ratio, resulting in a flux concentration ratio of 35 without additional secondary concentrator. An acceptance angle of ± 7.5° is achieved in the x-z plane due to the use of cylindrical lens array as the primary concentrator.

  14. Theoretical results on the tandem junction solar cell based on its Ebers-Moll transistor model

    NASA Technical Reports Server (NTRS)

    Goradia, C.; Vaughn, J.; Baraona, C. R.

    1980-01-01

    A one-dimensional theoretical model of the tandem junction solar cell (TJC) with base resistivity greater than about 1 ohm-cm and under low level injection has been derived. This model extends a previously published conceptual model which treats the TJC as an npn transistor. The model gives theoretical expressions for each of the Ebers-Moll type currents of the illuminated TJC and allows for the calculation of the spectral response, I(sc), V(oc), FF and eta under variation of one or more of the geometrical and material parameters and 1MeV electron fluence. Results of computer calculations based on this model are presented and discussed. These results indicate that for space applications, both a high beginning of life efficiency, greater than 15% AM0, and a high radiation tolerance can be achieved only with thin (less than 50 microns) TJC's with high base resistivity (greater than 10 ohm-cm).

  15. Modeling and Ab initio Calculations of Thermal Transport in Si-Based Clathrates and Solar Perovskites

    NASA Astrophysics Data System (ADS)

    He, Yuping

    2015-03-01

    We present calculations of the thermal transport coefficients of Si-based clathrates and solar perovskites, as obtained from ab initio calculations and models, where all input parameters derived from first principles. We elucidated the physical mechanisms responsible for the measured low thermal conductivity in Si-based clatherates and predicted their electronic properties and mobilities, which were later confirmed experimentally. We also predicted that by appropriately tuning the carrier concentration, the thermoelectric figure of merit of Sn and Pb based perovskites may reach values ranging between 1 and 2, which could possibly be further increased by optimizing the lattice thermal conductivity through engineering perovskite superlattices. Work done in collaboration with Prof. G. Galli, and supported by DOE/BES Grant No. DE-FG0206ER46262.

  16. Atmospheric Mining in the Outer Solar System: Outer Planet In-Space Bases and Moon Bases for Resource Processing

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2017-01-01

    Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and deuterium can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and deuterium were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of atmospheric mining in the outer solar system. This included the gas capturing rate, storage options, and different methods of direct use of the captured gases. While capturing 3He, large amounts of hydrogen and 4He are produced. The propulsion and transportation requirements for all of the major moons of Uranus and Neptune are presented. Analyses of orbital transfer vehicles (OTVs), landers, factories, and the issues with in-situ resource utilization (ISRU) low gravity processing factories are included. Preliminary observations are presented on near-optimal selections of moon base orbital locations, OTV power levels, and OTV and lander rendezvous points. Several artificial gravity in-space base designs and orbital sites at Uranus and Neptune and the OTV requirements to support them are also addressed.

  17. Turning Earth Abundant Kesterite-Based Solar Cells Into Efficient Protected Water-Splitting Photocathodes.

    PubMed

    Ros, Carles; Andreu, Teresa; Giraldo, Sergio; Izquierdo-Roca, Victor; Saucedo, Edgardo; Morante, Joan Ramon

    2018-04-25

    CZTS/Se kesterite-based solar cells have been protected by conformal atomic layer deposition (ALD)-deposited TiO 2 demonstrating its feasibility as powerful photocathodes for water splitting in highly acidic conditions (pH < 1), achieving stability with no detected degradation and with current density levels similar to photovoltaic productivities. The ALD has allowed low deposition temperatures of 200 °C for TiO 2 , preventing significant variations to the kesterite structure and CdS heterojunction, except for the pure-sulfide stoichiometry, which was studied by Raman spectroscopy. The measured photocurrent at 0 V vs reversible hydrogen electrode, 37 mA·cm -2 , is the highest reported to date, and the associated half-cell solar-to-hydrogen efficiency reached 7%, being amongst the largest presented for kesterite-based photocathodes, corroborating the possibility of using them as abundant low-cost alternative photoabsorbers as their efficiencies are improved toward those of chalcopyrites. An electrical circuit has been proposed to model the photocathode, which comprises the photon absorption, charge transfer through the protective layer, and catalytic performance, which paves the way to the design of highly efficient photoelectrodes.

  18. Probing molecular orientation of P3HT nanofibers in fiber-based organic solar cells

    NASA Astrophysics Data System (ADS)

    Yoon, Sangcheol; Han, Yaeeun; Hwang, Inchan

    2018-01-01

    Molecular orientation of conjugated polymers plays a key role in exciton generation/separation and charge transport, and thus significantly influence photovoltaic devices. Herein, we fabricated fiber-based organic solar cells and investigated the photovoltaic parameters with different diameters of fibers and PCBM diffusion. The open-circuit voltage that varies with molecular orientation whether it is face-on or edge-on was observed to differ. The investigation of the open-circuit voltage dependence reveals that thick fibers have core/shell like structures with different orientations. Thick fibers have face-on in the core and edge-on orientations in the shell. The face-on orientations are not preferentially formed in thin fibers, but the PCBM diffusion can induce face-on orientations that exist within the intermixed phase. Our results may shed a light on better understanding on fiber-based solar cells and suggest a way toward improving photovoltaic efficiency. [Figure not available: see fulltext.

  19. Numerical investigation of optimized CZTSSe based solar cell in Wx-Amps environment

    NASA Astrophysics Data System (ADS)

    Mohanty, Soumya Priyadarshini; Padhy, Srinibasa; Chowdhury, Joy; Sing, Udai P.

    2018-05-01

    The CZTSSe is the modified version of CZTS with selenium infusion. It shows maximum efficiency in the band gap from 1 to 1.4 eV. In our present work CZTSSe based solar cell is investigated using Wx-Amps tool. The Mo layer, absorber layer, CdS layer, i-ZnO [4]and Al-ZnO layers with their electrical, optical and material parameters are fitted in the tool. The vital parameters such as carrier density, thickness of the CZTSSe absorber layer, operating temperature, CdS buffer layer thickness and its carrier density on the cell interpretation are calculated. From[4] the simulation results it is apparent that the optimal absorber layer varies from 2.9 µm to 3.7 µm. The temperature variation has a strong influence on the efficiency of the cell. An optimal efficiency of 22% (With Jsc=33 mA/cm2, Voc=0.98 V, and fill factor= 68%) are attained. These results will give some insight for makeing higher efficiency CZTSSe based solar cell.

  20. High Efficiency Solar-based Catalytic Structure for CO 2 Reforming

    SciTech Connect

    Menkara, Hisham

    Throughout this project, we developed and optimized various photocatalyst structures for CO 2 reforming into hydrocarbon fuels and various commodity chemical products. We also built several closed-loop and continuous fixed-bed photocatalytic reactor system prototypes for a larger-scale demonstration of CO 2 reforming into hydrocarbons, mainly methane and formic acid. The results achieved have indicated that with each type of reactor and structure, high reforming yields can be obtained by refining the structural and operational conditions of the reactor, as well as by using various sacrificial agents (hole scavengers). We have also demonstrated, for the first time, that an aqueous solutionmore » containing acid whey (a common bio waste) is a highly effective hole scavenger for a solar-based photocatalytic reactor system and can help reform CO 2 into several products at once. The optimization tasks performed throughout the project have resulted in efficiency increase in our conventional reactors from an initial 0.02% to about 0.25%, which is 10X higher than our original project goal. When acid whey was used as a sacrificial agent, the achieved energy efficiency for formic acid alone was ~0.4%, which is 16X that of our original project goal and higher than anything ever reported for a solar-based photocatalytic reactor. Therefore, by carefully selecting sacrificial agents, it should be possible to reach energy efficiency in the range of the photosynthetic efficiency of typical crop and biofuel plants (1-3%).« less

  1. Specifications of ZnO growth for heterostructure solar cell and PC1D based simulations

    PubMed Central

    Hussain, Babar; Ebong, Abasifreke

    2015-01-01

    This data article is related to our recently published article (Hussain et al., in press [1]) where we have proposed a new solar cell model based on n-ZnO as front layer and p-Si as rear region. The ZnO layer will act as an active n-layer as well as antireflection (AR) coating saving considerable processing cost. There are several reports presenting use of ZnO as window/antireflection coating in solar cells (Mansoor et al., 2015; Haq et al., 2014; Hussain et al., 2014; Matsui et al., 2014; Ding et al., 2014 [2], [3], [4], [5], [6]) but, here, we provide data specifically related to simultaneous use of ZnO as n-layer and AR coating. Apart from the information we already published, we provide additional data related to growth of ZnO (with and without Ga incorporation) layers using MOCVD. The data related to PC1D based simulation of internal and external quantum efficiencies with and without antireflection effects of ZnO as well as the effects of doping level in p-Si on current–voltage characteristics have been provided. PMID:26587557

  2. Triazatruxene-Based Hole Transporting Materials for Highly Efficient Perovskite Solar Cells.

    PubMed

    Rakstys, Kasparas; Abate, Antonio; Dar, M Ibrahim; Gao, Peng; Jankauskas, Vygintas; Jacopin, Gwénolé; Kamarauskas, Egidijus; Kazim, Samrana; Ahmad, Shahzada; Grätzel, Michael; Nazeeruddin, Mohammad Khaja

    2015-12-30

    Four center symmetrical star-shaped hole transporting materials (HTMs) comprising planar triazatruxene core and electron-rich methoxy-engineered side arms have been synthesized and successfully employed in (FAPbI3)0.85(MAPbBr3)0.15 perovskite solar cells. These HTMs are obtained from relatively cheap starting materials by adopting facile preparation procedure, without using expensive and complicated purification techniques. Developed compounds have suitable highest occupied molecular orbitals (HOMO) with respect to the valence band level of the perovskite, and time-resolved photoluminescence indicates that hole injection from the valence band of perovskite into the HOMO of triazatruxene-based HTMs is relatively more efficient as compared to that of well-studied spiro-OMeTAD. Remarkable power conversion efficiency over 18% was achieved using 5,10,15-trihexyl-3,8,13-tris(4-methoxyphenyl)-10,15-dihydro-5H-diindolo[3,2-a:3',2'-c]carbazole (KR131) with compositive perovskite absorber. This result demonstrates triazatruxene-based compounds as a new class of HTM for the fabrication of highly efficient perovskite solar cells.

  3. Improved interface control for high-performance graphene-based organic solar cells

    NASA Astrophysics Data System (ADS)

    Jung, Seungon; Lee, Junghyun; Choi, Yunseong; Myeon Lee, Sang; Yang, Changduk; Park, Hyesung

    2017-12-01

    The demand for high-efficiency flexible optoelectronic devices is ever-increasing because next-generation electronic devices that comprise portable or wearable electronic systems are set to play an important role. Graphene has received extensive attention as it is considered to be a promising candidate material for transparent flexible electrode platforms owing to its outstanding electrical, optical, and physical properties. Despite these properties, the inert and hydrophobic nature of graphene surfaces renders it difficult to use in optoelectronic devices. In particular, commonly used charge transporting layer (CTL) materials for organic solar cells (OSCs) cannot uniformly coat a graphene surface, which leads to such devices failing. Herein, this paper proposes an approach that will enable CTL materials to completely cover a graphene electrode; this is done with the assistance of commonly accessible polar solvents. These are successfully applied to various configurations of OSCs, with power conversion efficiencies of 8.17% for graphene electrode-based c-OSCs (OSCs with conventional structures), 8.38% for i-OSCs (OSCs with inverted structures), and 7.53% for flexible solar cells. The proposed approach is expected to bring about significant advances for efficiency enhancements in graphene-based optoelectronic devices, and it is expected that it will open up new possibilities for flexible optoelectronic systems.

  4. Magnetic and optical effects in TiO2 based dye sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Kannan U., M.; Jammalamadaka, S. Narayana

    2018-04-01

    We report on the magnetic effects on the solar cell efficiency of TiO2 based dye sensitized solar cells (DSSC). The strong spin orbit coupling of rare earth Ho3+ ions introduced by the addition of Ho2O3 into the photoanode resulted in a 28% enhancement in the power conversion efficiency of DSSC. Such an enhancement in the efficiency may be attributed to the improved lifetime of photo generated excitons as a result of the accelerated intersystem crossing phenomenon. This observation is supported by our photoluminescence (PL) measurements where we could observe a decrease in the photo emission intensity with the addition of Ho2O3. In addition, we have used a low magnetic field of 100 Oe to further enhance the overall efficiency to 5.6%, which in turn proves that the Lorentz force plays a significant role in magnetic field controlled charge transport in DSSC. Finally, we have carried out a transfer matrix model based theoretical simulation for studying the optical properties of the multilayer device stack.

  5. Bioinspired Multifunctional Paper-Based rGO Composites for Solar-Driven Clean Water Generation.

    PubMed

    Lou, Jinwei; Liu, Yang; Wang, Zhongyong; Zhao, Dengwu; Song, Chengyi; Wu, Jianbo; Dasgupta, Neil; Zhang, Wang; Zhang, Di; Tao, Peng; Shang, Wen; Deng, Tao

    2016-06-15

    Reusing polluted water through various decontamination techniques has appeared as one of the most practical approaches to address the global shortage of clean water. Rather than relying on single decontamination mechanism, herein we report the preparation and utilization of paper-based composites for multifunctional solar-driven clean water generation that is inspired by the multiple water purification approaches in biological systems. The reduced graphene oxide (rGO) sheets within such composites can efficiently remove organic contaminants through physical adsorption mechanism. Under solar irradiation, the floating rGO composites can instantly generate localized heating, which not only can directly generate clean water through distillation mechanism but also significantly enhance adsorption removal performance with the assistance of upward vapor flow. Such porous-structured paper-based composites allow for facile incorporation of photocatalysts to regenerate clean water out of contaminated water with combined adsorption, photodegradation, and interfacial heat-assisted distillation mechanisms. Within a homemade all-in-one water treatment device, the practical applicability of the composites for multifunctional clean water generation has been demonstrated.

  6. Evaluation of physics-based numerical modelling for diverse design architecture of perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Mishra, A. K.; Catalan, Jorge; Camacho, Diana; Martinez, Miguel; Hodges, D.

    2017-08-01

    Solution processed organic-inorganic metal halide perovskite based solar cells are emerging as a new cost effective photovoltaic technology. In the context of increasing the power conversion efficiency (PCE) and sustainability of perovskite solar cells (PSC) devices, we comprehensively analyzed a physics-based numerical modelling for doped and un-doped PSC devices. Our analytics emphasized the role of different charge carrier layers from the view point of interfacial adhesion and its influence on charge extraction rate and charge recombination mechanism. Morphological and charge transport properties of perovskite thin film as a function of device architecture are also considered to investigate the photovoltaic properties of PSC. We observed that photocurrent is dominantly influenced by interfacial recombination process and photovoltage has functional relationship with defect density of perovskite absorption layer. A novel contour mapping method to understand the characteristics of current density-voltage (J-V) curves for each device as a function of perovskite layer thickness provide an important insight about the distribution spectrum of photovoltaic properties. Functional relationship of device efficiency and fill factor with absorption layer thickness are also discussed.

  7. Intensification of depolymerization of polyacrylic acid solution using different approaches based on ultrasound and solar irradiation with intensification studies.

    PubMed

    Prajapat, Amrutlal L; Gogate, Parag R

    2016-09-01

    Depolymerization of polyacrylic acid (PAA) as sodium salt has been investigated using ultrasonic and solar irradiations with process intensification studies based on combination with hydrogen peroxide (H2O2) and ozone (O3). Effect of solar intensity, ozone flow and ultrasonic power dissipation on the extent of viscosity reduction has been investigated for individual treatment approaches. The combined approaches such as US+solar, solar+O3, solar+H2O2, US+H2O2 and US+O3 have been subsequently investigated under optimum conditions and established to be more efficient as compared to individual approaches. Approach based on US (60W)+solar+H2O2 (0.01%) resulted in the maximum extent of viscosity reduction as 98.97% in 35min whereas operation of solar+H2O2 (0.01%), US (60W), H2O2 (0.3%) and solar irradiation resulted in about 98.08%, 90.13%, 8.91% and 90.77% intrinsic viscosity reduction in 60min respectively. Approach of US (60W)+solar+ozone (400mg/h flow rate) resulted in extent of viscosity reduction as 99.47% in 35min whereas only ozone (400mg/h flow rate), ozone (400mg/h flow rate)+US (60W) and ozone (400mg/h flow rate)+solar resulted in 69.04%, 98.97% and 98.51% reduction in 60min, 55min and 55min respectively. The chemical identity of the treated polymer using combined approaches was also characterized using FTIR (Fourier transform infrared) spectra and it was established that no significant structural changes were obtained during the treatment. Overall, it can be said that the combination technique based on US and solar irradiations in the presence of hydrogen peroxide is the best approach for the depolymerization of PAA solution. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Two-dimensional high efficiency thin-film silicon solar cells with a lateral light trapping architecture.

    PubMed

    Fang, Jia; Liu, Bofei; Zhao, Ying; Zhang, Xiaodan

    2014-08-22

    Introducing light trapping structures into thin-film solar cells has the potential to enhance their solar energy harvesting as well as the performance of the cells; however, current strategies have been focused mainly on harvesting photons without considering the light re-escaping from cells in two-dimensional scales. The lateral out-coupled solar energy loss from the marginal areas of cells has reduced the electrical yield indeed. We therefore herein propose a lateral light trapping structure (LLTS) as a means of improving the light-harvesting capacity and performance of cells, achieving a 13.07% initial efficiency and greatly improved current output of a-Si:H single-junction solar cell based on this architecture. Given the unique transparency characteristics of thin-film solar cells, this proposed architecture has great potential for integration into the windows of buildings, microelectronics and other applications requiring transparent components.

  9. Bulk heterojunction perovskite solar cells based on room temperature deposited hole-blocking layer: Suppressed hysteresis and flexible photovoltaic application

    NASA Astrophysics Data System (ADS)

    Chen, Zhiliang; Yang, Guang; Zheng, Xiaolu; Lei, Hongwei; Chen, Cong; Ma, Junjie; Wang, Hao; Fang, Guojia

    2017-05-01

    Perovskite solar cells have developed rapidly in recent years as the third generation solar cells. In spite of the great improvement achieved, there still exist some issues such as undesired hysteresis and indispensable high temperature process. In this work, bulk heterojunction perovskite-phenyl-C61-butyric acid methyl ester solar cells have been prepared to diminish hysteresis using a facile two step spin-coating method. Furthermore, high quality tin oxide films are fabricated using pulse laser deposition technique at room temperature without any annealing procedure. The as fabricated tin oxide film is successfully applied in bulk heterojunction perovskite solar cells as a hole blocking layer. Bulk heterojunction devices based on room temperature tin oxide exhibit almost hysteresis-free characteristics with power conversion efficiency of 17.29% and 14.0% on rigid and flexible substrates, respectively.

  10. A compact Dopplergraph/magnetograph suitable for space-based measurements of solar oscillations and magnetic fields

    NASA Technical Reports Server (NTRS)

    Rhodes, E. J., Jr.; Cacciani, A.; Tomczyk, S.; Ulrich, R. K.; Blamont, J.; Howard, R. F.; Dumont, P.; Smith, E. J.

    1984-01-01

    A compact Dopplergraph/magnetograph placed in a continuous solar-viewing orbit will allow us to make major advancements in our understanding of solar internal structure and dynamics. An international program is currently being conducted at JPL and Mt. Wilson to develop such an instrument. By combining a unique magneto-optical resonance filter with CID and CCD cameras we have been able to obtain full- and partial-disk Dopplergrams and magnetograms. Time series of the velocity images are converted into k-omega power spectra which show clear- the solar nonradial p-mode oscilations. Magnetograms suitable for studying the long-term evolution of solar active regions have also been obtained with this instrument. A flight instrument based on this concept is being studied for possible inclusion in the SOHO mission.

  11. Preliminary tests of silicon carbide based concretes for hybrid rocket nozzles in a solar furnace

    NASA Astrophysics Data System (ADS)

    D'Elia, Raffaele; Bernhart, Gérard; Cutard, Thierry; Peraudeau, Gilles; Balat-Pichelin, Marianne

    2014-06-01

    This research is part of the PERSEUS project, a space program concerning hybrid propulsion and supported by CNES. The main goal of this study is to characterise silicon carbide based micro-concrete with a maximum aggregates size of 800 μm, in a hybrid propulsion environment. The nozzle throat has to resist to a highly oxidising polyethylene (PE)/N2O hybrid environment, under temperatures ranging up to 2980 K. The study is divided into two main parts: the first one deals with the thermo-mechanical characterisation of the material up to 1500 K and the second one with an investigation on the oxidation behaviour in a standard atmosphere, under a solar flux up to 13.5 MW/m2. Young's modulus was determined by resonant frequency method: results show an increase with the stabilisation temperature. Four point bending tests have shown a rupture tensile strength increasing with stabilisation temperature, up to 1473 K. Sintering and densification processes are primary causes of this phenomenon. Visco-plastic behaviour appears at 1373 K, due to the formation of liquid phases in cement ternary system. High-temperature oxidation in ambient air was carried out at PROMES-CNRS laboratory, on a 2 kW solar furnace, with a concentration factor of 15,000. A maximum 13.5 MW/m2 incident solar flux and a 7-90 s exposure times have been chosen. Optical microscopy, SEM, EDS analyses were used to determine the microstructure evolution and the mass loss kinetics. During these tests, silicon carbide undergoes active oxidation with production of SiO and CO smokes and ablation. A linear relation between mass loss and time is found. Oxidation tests performed at 13.5 MW/m2 solar flux have shown a mass loss of 10 mg/cm2 after 15 s. After 90 s, the mass loss reaches 60 mg/cm2. Surface temperature measurement is a main point in this study, because of necessity of a thermo-mechanical-ablative model for the material. Smokes appear at around 5.9 MW/m2, leading to the impossibility of useful temperature

  12. High-performance Förster resonance energy transfer (FRET)-based dye-sensitized solar cells: rational design of quantum dots for wide solar-spectrum utilization.

    PubMed

    Lee, Eunwoo; Kim, Chanhoi; Jang, Jyongsik

    2013-07-29

    High-performance Förster resonance energy transfer (FRET)-based dye-sensitized solar cells (DSSCs) have been successfully fabricated through the optimized design of a CdSe/CdS quantum-dot (QD) donor and a dye acceptor. This simple approach enables quantum dots and dyes to simultaneously utilize the wide solar spectrum, thereby resulting in high conversion efficiency over a wide wavelength range. In addition, major parameters that affect the FRET interaction between donor and acceptor have been investigated including the fluorescent emission spectrum of QD, and the content of deposited QDs into the TiO2 matrix. By judicious control of these parameters, the FRET interaction can be readily optimized for high photovoltaic performance. In addition, the as-synthesized water-soluble quantum dots were highly dispersed in a nanoporous TiO2 matrix, thereby resulting in excellent contact between donors and acceptors. Importantly, high-performance FRET-based DSSCs can be prepared without any infrared (IR) dye synthetic procedures. This novel strategy offers great potential for applications of dye-sensitized solar cells. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Improved performance of flexible amorphous silicon solar cells with silver nanowires

    NASA Astrophysics Data System (ADS)

    Chen, Y. R.; Li, Z. Q.; Chen, X. H.; Liu, C.; Ye, X. J.; Wang, Z. B.; Sun, Z.; Huang, S. M.

    2012-12-01

    A novel hybrid electrode structure using Ag nanowires (NWs) to create surface plasmons to enhance light trapping is designed and applied on the front surface of hydrogenated amorphous silicon (a-Si:H) solar cells on steel substrates, targeting broad-band absorption enhancements. Ag NWs were synthesized using a soft and self-seeding process. The produced Ag NWs were deposited on indium tin oxide (ITO) glass substrates or the ITO layers of the as-prepared flexible a-Si:H solar cells to form Ag NW-ITO hybrid electrodes. The Ag NW-ITO hybrid electrodes were optimized to achieve maximum optical enhancement using surface plasmons and obtain good electrical contacts in cells. Finite-element electromagnetic simulations confirmed that the presence of the Ag NWs resulted in increased electromagnetic fields within the a-Si:H layer. Compared to the cell with conventional ITO electrode, the measured quantum efficiency of the best performing a-Si:H cell shows an obvious enhancement in the wavelength range from 330 nm to 600 nm. The cell based on the optimized Ag NW-ITO demonstrates an increase about 4% in short-circuit current density and over 6% in power conversion efficiency under AM 1.5 illumination.

  14. Statistical Prediction of Solar Particle Event Frequency Based on the Measurements of Recent Solar Cycles for Acute Radiation Risk Analysis

    NASA Technical Reports Server (NTRS)

    Myung-Hee, Y. Kim; Shaowen, Hu; Cucinotta, Francis A.

    2009-01-01

    Large solar particle events (SPEs) present significant acute radiation risks to the crew members during extra-vehicular activities (EVAs) or in lightly shielded space vehicles for space missions beyond the protection of the Earth's magnetic field. Acute radiation sickness (ARS) can impair performance and result in failure of the mission. Improved forecasting capability and/or early-warning systems and proper shielding solutions are required to stay within NASA's short-term dose limits. Exactly how to make use of observations of SPEs for predicting occurrence and size is a great challenge, because SPE occurrences themselves are random in nature even though the expected frequency of SPEs is strongly influenced by the time position within the solar activity cycle. Therefore, we developed a probabilistic model approach, where a cumulative expected occurrence curve of SPEs for a typical solar cycle was formed from a non-homogeneous Poisson process model fitted to a database of proton fluence measurements of SPEs that occurred during the past 5 solar cycles (19 - 23) and those of large SPEs identified from impulsive nitrate enhancements in polar ice. From the fitted model, the expected frequency of SPEs was estimated at any given proton fluence threshold (Phi(sub E)) with energy (E) >30 MeV during a defined space mission period. Corresponding Phi(sub E) (E=30, 60, and 100 MeV) fluence distributions were simulated with a random draw from a gamma distribution, and applied for SPE ARS risk analysis for a specific mission period. It has been found that the accurate prediction of deep-seated organ doses was more precisely predicted at high energies, Phi(sub 100), than at lower energies such as Phi(sub 30) or Phi(sub 60), because of the high penetration depth of high energy protons. Estimates of ARS are then described for 90th and 95th percentile events for several mission lengths and for several likely organ dose-rates. The ability to accurately measure high energy protons

  15. Statistical Prediction of Solar Particle Event Frequency based on the Measurements of Recent Solar Cycles for Acute Radiation Risk Analysis

    NASA Astrophysics Data System (ADS)

    Kim, M. Y.; Hu, S.; Cucinotta, F. A.

    2009-12-01

    Large solar particle events (SPEs) present significant acute radiation risks to the crew members during extra-vehicular activities (EVAs) or in lightly shielded space vehicles for space missions beyond the protection of the Earth’s magnetic field. Acute radiation sickness (ARS) can impair performance and result in failure of the mission. Improved forecasting capability and/or early-warning systems and proper shielding solutions are required to stay within NASA’s short-term dose limits. Exactly how to make use of observations of SPEs for predicting occurrence and size is a great challenge, because SPE occurrences themselves are random in nature even though the expected frequency of SPEs is strongly influenced by the time position within the solar activity cycle. Therefore, we developed a probabilistic model approach, where a cumulative expected occurrence curve of SPEs for a typical solar cycle was formed from a non-homogeneous Poisson process model fitted to a database of proton fluence measurements of SPEs that occurred during the past 5 solar cycles (19 -23) and those of large SPEs identified from impulsive nitrate enhancements in polar ice. From the fitted model, the expected frequency of SPEs was estimated at any given proton fluence threshold (ΦE) with energy (E) >30 MeV during a defined space mission period. Corresponding ΦE (E=30, 60, and 100 MeV) fluence distributions were simulated with a random draw from a gamma distribution, and applied for SPE ARS risk analysis for a specific mission period. It has been found that the accurate prediction of deep-seated organ doses was more precisely predicted at high energies, Φ100, than at lower energies such as Φ30 or Φ60, because of the high penetration depth of high energy protons. Estimates of ARS are then described for 90th and 95th percentile events for several mission lengths and for several likely organ dose-rates. The ability to accurately measure high energy protons (50-300 MeV) in real-time is shown

  16. Atmospheric turbulence and high-precision ground-based solar polarimetry

    NASA Astrophysics Data System (ADS)

    Nagaraju, K.; Feller, A.; Ihle, S.; Soltau, H.

    2011-10-01

    High-precision full-Stokes polarimetry at near diffraction limited spatial resolution is important to understand numerous physical processes on the Sun. In view of the next generation of ground based solar telescopes, we have explored, through numerical simulation, how polarimetric accuracy is affected by atmospheric seeing, especially in the case of large aperture telescopes with increasing ratio between mirror diameter and Fried parameter. In this work we focus on higher-order wavefront aberrations. The numerical generation of time-dependent turbulence phase screens is based on the well-known power spectral method and on the assumption that the temporal evolution is mainly caused by wind driven propagation of frozen-in turbulence across the telescope. To analyze the seeing induced cross-talk between the Stokes parameters we consider polarization modulation scheme based on a continuously rotating waveplate with rotation frequencies between 1 Hz and several 100 Hz. Further, we have started the development of a new fast solar imaging polarimeter, based on pnCCD detector technology from PNSensor. The first detector will have a size of 264 x 264 pixels and will work at frame rates of up to 1kHz, combined with a very low readout noise of 2-3 e- ENC. The camera readout electronics will allow for buffering and accumulation of images corresponding to the different phases of the fast polarization modulation. A high write-out rate (about 30 to 50 frames/s) will allow for post-facto image reconstruction. We will present the concept and the expected performance of the new polarimeter, based on the above-mentioned simulations of atmospheric seeing.

  17. Space-Based Solar Power: A Technical, Economic, and Operational Assessment

    DTIC Science & Technology

    2015-04-01

    reports also address alternative and renew- able sources such as biomass, wind, geothermal , and solar (thermal and photovoltaic), which are becom- ing...2025 using solar, wind, biomass, and geothermal energy generation technologies.86 Table 3. Army Sites for Terrestrial Solar Photovoltaic Power

  18. Solar electricity and solar fuels

    NASA Astrophysics Data System (ADS)

    Spiers, David J.

    1989-04-01

    The nature of solar radiation and its variation with location is described. The distribution of energy in the solar spectrum places immediate limits on the theoretical efficiency of conversion processes, since practical absorbers cannot convert all wavelengths received to useful energy. The principles of solar energy conversion methods are described. Absorption of solar energy can give rise to direct electrical generation, heating, or chemical change. Electrical generation from sunlight can be achieved by photovoltaic systems directly or by thermal systems which use solar heat to drive a heat engine and generator. The technology used and under research for promising ways of producing electricity or fuel from solar energy is described. Photovoltaic technology is established today for remote area, small power applications, and photovoltaic module sales alone are over 100 million dollars per year at present. The photovoltaic market has grown steadily since the mid-1970's, as prices have fallen continuously. Future energy options are briefly described. The merits of a sustainable energy economy, based on renewable energy resources, including solar energy, are emphasized, as this seems to provide the only hope of eliminating the problems caused by the build-up of atmospheric carbon dioxide, acid rain pollution and nuclear waste disposal. There is no doubt that clean fuels which were derived from solar energy and either did not involve carbon dioxide and used atmospheric carbon dioxide as the source dioxide as the source of carbon would be a worthy ideal. Methods described could one day achieve this.

  19. Fabrication of Sb₂S₃ Hybrid Solar Cells Based on Embedded Photoelectrodes of Ag Nanowires-Au Nanoparticles Composite.

    PubMed

    Kim, Kang-Pil; Hwang, Dae-Kue; Woo, Sung-Ho; Kim, Dae-Hwan

    2018-09-01

    The Ag nanowire (NW) + Au nanoparticle (NP)-embedded TiO2 photoelectrodes were adopted for conventional planar TiO2-based Sb2S3 hybrid solar cells to improve the cell efficiency. Compared to conventional planar TiO2-based Sb2S3 hybrid solar cells, the Ag NW + Au NP/TiO2-based Sb2S3 hybrid solar cells exhibited an improvement of approximately 40% in the cell efficiency due to the significant increase in both Jsc and Voc. These enhanced Jsc and Voc were attributed to the increased surface area, charge-collection efficiency, and light absorption by embedding the Ag NWs + Au NPs composite. The Ag NW + Au NP/TiO2-based Sb2S3 hybrid solar cells showed the highest efficiency of 2.17%, demonstrating that the Ag NW + Au NP-embedded TiO2 photoelectrode was a suitable photoelectrode structure to improve the power conversion efficiency in the Sb2S3 hybrid solar cells.

  20. Physics-based Space Weather Forecasting in the Project for Solar-Terrestrial Environment Prediction (PSTEP) in Japan

    NASA Astrophysics Data System (ADS)

    Kusano, K.

    2016-12-01

    Project for Solar-Terrestrial Environment Prediction (PSTEP) is a Japanese nation-wide research collaboration, which was recently launched. PSTEP aims to develop a synergistic interaction between predictive and scientific studies of the solar-terrestrial environment and to establish the basis for next-generation space weather forecasting using the state-of-the-art observation systems and the physics-based models. For this project, we coordinate the four research groups, which develop (1) the integration of space weather forecast system, (2) the physics-based solar storm prediction, (3) the predictive models of magnetosphere and ionosphere dynamics, and (4) the model of solar cycle activity and its impact on climate, respectively. In this project, we will build the coordinated physics-based model to answer the fundamental questions concerning the onset of solar eruptions and the mechanism for radiation belt dynamics in the Earth's magnetosphere. In this paper, we will show the strategy of PSTEP, and discuss about the role and prospect of the physics-based space weather forecasting system being developed by PSTEP.

  1. Graphene as a transparent electrode for amorphous silicon-based solar cells

    NASA Astrophysics Data System (ADS)

    Vaianella, F.; Rosolen, G.; Maes, B.

    2015-06-01

    The properties of graphene in terms of transparency and conductivity make it an ideal candidate to replace indium tin oxide (ITO) in a transparent conducting electrode. However, graphene is not always as good as ITO for some applications, due to a non-negligible absorption. For amorphous silicon photovoltaics, we have identified a useful case with a graphene-silica front electrode that improves upon ITO. For both electrode technologies, we simulate the weighted absorption in the active layer of planar amorphous silicon-based solar cells with a silver back-reflector. The graphene device shows a significantly increased absorbance compared to ITO-based cells for a large range of silicon thicknesses (34.4% versus 30.9% for a 300 nm thick silicon layer), and this result persists over a wide range of incidence angles.

  2. Investigation of Quasi-periodic Solar Oscillations in Sunspots Based on SOHO/MDI Magnetograms

    NASA Astrophysics Data System (ADS)

    Kallunki, J.; Riehokainen, A.

    2012-10-01

    In this work we study quasi-periodic solar oscillations in sunspots, based on the variation of the amplitude of the magnetic field strength and the variation of the sunspot area. We investigate long-period oscillations between three minutes and ten hours. The magnetic field synoptic maps were obtained from the SOHO/MDI. Wavelet (Morlet), global wavelet spectrum (GWS) and fast Fourier transform (FFT) methods are used in the periodicity analysis at the 95 % significance level. Additionally, the quiet Sun area (QSA) signal and an instrumental effect are discussed. We find several oscillation periods in the sunspots above the 95 % significance level: 3 - 5, 10 - 23, 220 - 240, 340 and 470 minutes, and we also find common oscillation periods (10 - 23 minutes) between the sunspot area variation and that of the magnetic field strength. We discuss possible mechanisms for the obtained results, based on the existing models for sunspot oscillations.

  3. Ultrathin Polyaniline-based Buffer Layer for Highly Efficient Polymer Solar Cells with Wide Applicability

    PubMed Central

    Zhao, Wenchao; Ye, Long; Zhang, Shaoqing; Fan, Bin; Sun, Mingliang; Hou, Jianhui

    2014-01-01

    Interfacial buffer layers often attribute the improved device performance in organic optoelectronic device. Herein, a water-soluble hydrochloric acid doped polyanilines (HAPAN) were utilized as p-type electrode buffer layer in highly efficient polymer solar cells (PSC) based on PBDTTT-EFT and several representative polymers. The PBDTTT-EFT-based conventional PSC featuring ultrathin HAPAN (1.3 nm) delivered high PCE approximately 9%, which is one of the highest values among conventional PSC devices. Moreover, ultrathin HAPAN also exhibited wide applicability in a variety of efficient photovoltaic polymers including PBDTTT-C-T, PTB7, PBDTBDD, PBTTDPP-T, PDPP3T and P3HT. The excellent performances were originated from the high transparency, small film roughness and suitable work function. PMID:25300365

  4. Optimal placement and sizing of wind / solar based DG sources in distribution system

    NASA Astrophysics Data System (ADS)

    Guan, Wanlin; Guo, Niao; Yu, Chunlai; Chen, Xiaoguang; Yu, Haiyang; Liu, Zhipeng; Cui, Jiapeng

    2017-06-01

    Proper placement and sizing of Distributed Generation (DG) in distribution system can obtain maximum potential benefits. This paper proposes quantum particle swarm algorithm (QPSO) based wind turbine generation unit (WTGU) and photovoltaic (PV) array placement and sizing approach for real power loss reduction and voltage stability improvement of distribution system. Performance modeling of wind and solar generation system are described and classified into PQ\\PQ (V)\\PI type models in power flow. Considering the WTGU and PV based DGs in distribution system is geographical restrictive, the optimal area and DG capacity limits of each bus in the setting area need to be set before optimization, the area optimization method is proposed . The method has been tested on IEEE 33-bus radial distribution systems to demonstrate the performance and effectiveness of the proposed method.

  5. Amorphous silicon carbide passivating layers for crystalline-silicon-based heterojunction solar cells

    SciTech Connect

    Boccard, Mathieu; Holman, Zachary C.

    Amorphous silicon enables the fabrication of very high-efficiency crystalline-silicon-based solar cells due to its combination of excellent passivation of the crystalline silicon surface and permeability to electrical charges. Yet, amongst other limitations, the passivation it provides degrades upon high-temperature processes, limiting possible post-deposition fabrication possibilities (e.g., forcing the use of low-temperature silver pastes). We investigate the potential use of intrinsic amorphous silicon carbide passivating layers to sidestep this issue. The passivation obtained using device-relevant stacks of intrinsic amorphous silicon carbide with various carbon contents and doped amorphous silicon are evaluated, and their stability upon annealing assessed, amorphous silicon carbide beingmore » shown to surpass amorphous silicon for temperatures above 300 °C. We demonstrate open-circuit voltage values over 700 mV for complete cells, and an improved temperature stability for the open-circuit voltage. Transport of electrons and holes across the hetero-interface is studied with complete cells having amorphous silicon carbide either on the hole-extracting side or on the electron-extracting side, and a better transport of holes than of electrons is shown. Also, due to slightly improved transparency, complete solar cells using an amorphous silicon carbide passivation layer on the hole-collecting side are demonstrated to show slightly better performances even prior to annealing than obtained with a standard amorphous silicon layer.« less

  6. Amorphous silicon carbide passivating layers for crystalline-silicon-based heterojunction solar cells

    SciTech Connect

    Boccard, Mathieu; Holman, Zachary C.

    With this study, amorphous silicon enables the fabrication of very high-efficiency crystalline-silicon-based solar cells due to its combination of excellent passivation of the crystalline silicon surface and permeability to electrical charges. Yet, amongst other limitations, the passivation it provides degrades upon high-temperature processes, limiting possible post-deposition fabrication possibilities (e.g., forcing the use of low-temperature silver pastes). We investigate the potential use of intrinsic amorphous silicon carbide passivating layers to sidestep this issue. The passivation obtained using device-relevant stacks of intrinsic amorphous silicon carbide with various carbon contents and doped amorphous silicon are evaluated, and their stability upon annealing assessed, amorphousmore » silicon carbide being shown to surpass amorphous silicon for temperatures above 300°C. We demonstrate open-circuit voltage values over 700 mV for complete cells, and an improved temperature stability for the open-circuit voltage. Transport of electrons and holes across the hetero-interface is studied with complete cells having amorphous silicon carbide either on the hole-extracting side or on the electron-extracting side, and a better transport of holes than of electrons is shown. Also, due to slightly improved transparency, complete solar cells using an amorphous silicon carbide passivation layer on the hole-collecting side are demonstrated to show slightly better performances even prior to annealing than obtained with a standard amorphous silicon layer.« less

  7. InGaN-based thin film solar cells: Epitaxy, structural design, and photovoltaic properties

    NASA Astrophysics Data System (ADS)

    Sang, Liwen; Liao, Meiyong; Koide, Yasuo; Sumiya, Masatomo

    2015-03-01

    InxGa1-xN, with the tunable direct bandgaps from ultraviolet to near infrared region, offers a promising candidate for the high-efficiency next-generation thin-film photovoltaic applications. Although the adoption of thick InGaN film as the active region is desirable to obtain efficient light absorption and carrier collection compared to InGaN/GaN quantum wells structure, the understanding on the effect from structural design is still unclear due to the poor-quality InGaN films with thickness and difficulty of p-type doping. In this paper, we comprehensively investigate the effects from film epitaxy, doping, and device structural design on the performances of the InGaN-based solar cells. The high-quality InGaN thick film is obtained on AlN/sapphire template, and p-In0.08Ga0.92N is achieved with a high hole concentration of more than 1018 cm-3. The dependence of the photovoltaic performances on different structures, such as active regions and p-type regions is analyzed with respect to the carrier transport mechanism in the dark and under illumination. The strategy of improving the p-i interface by using a super-thin AlN interlayer is provided, which successfully enhances the performance of the solar cells.

  8. Space-based solar power conversion and delivery systems study. Volume 5: Economic analysis

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Space-based solar power conversion and delivery systems are studied along with a variety of economic and programmatic issues relevant to their development and deployment. The costs, uncertainties and risks associated with the current photovoltaic Satellite Solar Power System (SSPS) configuration, and issues affecting the development of an economically viable SSPS development program are addressed. In particular, the desirability of low earth orbit (LEO) and geosynchronous (GEO) test satellites is examined and critical technology areas are identified. The development of SSPS unit production (nth item), and operation and maintenance cost models suitable for incorporation into a risk assessment (Monte Carlo) model (RAM) are reported. The RAM was then used to evaluate the current SSPS configuration expected costs and cost-risk associated with this configuration. By examining differential costs and cost-risk as a function of postulated technology developments, the critical technologies, that is, those which drive costs and/or cost-risk, are identified. It is shown that the key technology area deals with productivity in space, that is, the ability to fabricate and assemble large structures in space, not, as might be expected, with some hardware component technology.

  9. Toward Perovskite Solar Cell Commercialization: A Perspective and Research Roadmap Based on Interfacial Engineering.

    PubMed

    Rajagopal, Adharsh; Yao, Kai; Jen, Alex K-Y

    2018-06-08

    High-efficiency and low-cost perovskite solar cells (PVKSCs) are an ideal candidate for addressing the scalability challenge of solar-based renewable energy. The dynamically evolving research field of PVKSCs has made immense progress in solving inherent challenges and capitalizing on their unique structure-property-processing-performance traits. This review offers a unique outlook on the paths toward commercialization of PVKSCs from the interfacial engineering perspective, relevant to both specialists and nonspecialists in the field through a brief introduction of the background of the field, current state-of-the-art evolution, and future research prospects. The multifaceted role of interfaces in facilitating PVKSC development is explained. Beneficial impacts of diverse charge-transporting materials and interfacial modifications are summarized. In addition, the role of interfaces in improving efficiency and stability for all emerging areas of PVKSC design are also evaluated. The authors' integral contributions in this area are highlighted on all fronts. Finally, future research opportunities for interfacial material development and applications along with scalability-durability-sustainability considerations pivotal for facilitating laboratory to industry translation are presented. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Transparent Electrode Based on Silver Nanowires and Polyimide for Film Heater and Flexible Solar Cell

    PubMed Central

    He, Xin; Duan, Feng; Liu, Junyan; Lan, Qiuming; Wu, Jianhao; Yang, Chengyan; Yang, Weijia; Zeng, Qingguang; Wang, Huafang

    2017-01-01

    Transparent, conductive, and flexible Ag nanowire (NW)-polyimide (PI) composite films were fabricated by a facile solution method. Well-dispersed Ag NWs result in percolation networks on the PI supporting layer. A series of films with transmittance values of 53–80% and sheet resistances of 2.8–16.5 Ω/sq were investigated. To further verify the practicability of the Ag NWs-PI film in optoelectronic devices, we utilized it in a film heater and a flexible solar cell. The film heater was able to generate a temperature of 58 °C at a driving voltage of 3.5 V within 20 s, indicating its potential application in heating devices that require low power consumption and fast response. The flexible solar cell based on the composite film with a transmittance value of 71% presented a power conversion efficiency of 3.53%. These successful applications proved that the fabricated Ag NWs-PI composite film is a good candidate for application in flexible optoelectronic devices. PMID:29186012

  11. Amorphous silicon carbide passivating layers for crystalline-silicon-based heterojunction solar cells

    DOE PAGES

    Boccard, Mathieu; Holman, Zachary C.

    2015-08-14

    With this study, amorphous silicon enables the fabrication of very high-efficiency crystalline-silicon-based solar cells due to its combination of excellent passivation of the crystalline silicon surface and permeability to electrical charges. Yet, amongst other limitations, the passivation it provides degrades upon high-temperature processes, limiting possible post-deposition fabrication possibilities (e.g., forcing the use of low-temperature silver pastes). We investigate the potential use of intrinsic amorphous silicon carbide passivating layers to sidestep this issue. The passivation obtained using device-relevant stacks of intrinsic amorphous silicon carbide with various carbon contents and doped amorphous silicon are evaluated, and their stability upon annealing assessed, amorphousmore » silicon carbide being shown to surpass amorphous silicon for temperatures above 300°C. We demonstrate open-circuit voltage values over 700 mV for complete cells, and an improved temperature stability for the open-circuit voltage. Transport of electrons and holes across the hetero-interface is studied with complete cells having amorphous silicon carbide either on the hole-extracting side or on the electron-extracting side, and a better transport of holes than of electrons is shown. Also, due to slightly improved transparency, complete solar cells using an amorphous silicon carbide passivation layer on the hole-collecting side are demonstrated to show slightly better performances even prior to annealing than obtained with a standard amorphous silicon layer.« less

  12. Evaluation and prediction of solar radiation for energy management based on neural networks

    NASA Astrophysics Data System (ADS)

    Aldoshina, O. V.; Van Tai, Dinh

    2017-08-01

    Currently, there is a high rate of distribution of renewable energy sources and distributed power generation based on intelligent networks; therefore, meteorological forecasts are particularly useful for planning and managing the energy system in order to increase its overall efficiency and productivity. The application of artificial neural networks (ANN) in the field of photovoltaic energy is presented in this article. Implemented in this study, two periodically repeating dynamic ANS, that are the concentration of the time delay of a neural network (CTDNN) and the non-linear autoregression of a network with exogenous inputs of the NAEI, are used in the development of a model for estimating and daily forecasting of solar radiation. ANN show good productivity, as reliable and accurate models of daily solar radiation are obtained. This allows to successfully predict the photovoltaic output power for this installation. The potential of the proposed method for controlling the energy of the electrical network is shown using the example of the application of the NAEI network for predicting the electric load.

  13. Design and cost analysis for an ammonia-based solar thermochemical cavity absorber

    NASA Astrophysics Data System (ADS)

    Williams, O. M.

    1980-01-01

    A design and cost analysis is introduced for a solar thermochemical cavity absorber operated at the focus of a tracking paraboloidal concentrator and based on the ammonia dissociation reaction. The absorber design consists of a catalyst-filled nickel alloy tube wound into a spiral forming the inner cavity wall and shaped to match the incident power density profile to the reactor heat requirements. The reactor tube is welded to a coaxial counterflow heat exchanger. The relationships among the power density profile, the reaction thermodynamics and kinetics, and the heat transfer characteristics are examined in detail and it is shown that an installed cost goal of typically 10 U.S. dollars per square meter of solar collector area can be achieved through use of high activity ammonia dissociation catalyst. The optimum absorber size for a given paraboloidal dish area is calculated for a system pressure of 20 MPa and it is shown that a cost effective absorber suitable for 100,000-hr operation would operate at 90% efficiency at 750 C wall temperature.

  14. Application of amorphous carbon based materials as antireflective coatings on crystalline silicon solar cells

    NASA Astrophysics Data System (ADS)

    da Silva, D. S.; Côrtes, A. D. S.; Oliveira, M. H.; Motta, E. F.; Viana, G. A.; Mei, P. R.; Marques, F. C.

    2011-08-01

    We report on the investigation of the potential application of different forms of amorphous carbon (a-C and a-C:H) as an antireflective coating for crystalline silicon solar cells. Polymeric-like carbon (PLC) and hydrogenated diamond-like carbon films were deposited by plasma enhanced chemical vapor deposition. Tetrahedral amorphous carbon (ta-C) was deposited by the filtered cathodic vacuum arc technique. Those three different amorphous carbon structures were individually applied as single antireflective coatings on conventional (polished and texturized) p-n junction crystalline silicon solar cells. Due to their optical properties, good results were also obtained for double-layer antireflective coatings based on PLC or ta-C films combined with different materials. The results are compared with a conventional tin dioxide (SnO2) single-layer antireflective coating and zinc sulfide/magnesium fluoride (ZnS/MgF2) double-layer antireflective coatings. An increase of 23.7% in the short-circuit current density, Jsc, was obtained using PLC as an antireflective coating and 31.7% was achieved using a double-layer of PLC with a layer of magnesium fluoride (MgF2). An additional increase of 10.8% was obtained in texturized silicon, representing a total increase (texturization + double-layer) of about 40% in the short-circuit current density. The potential use of these materials are critically addressed considering their refractive index, optical bandgap, absorption coefficient, hardness, chemical inertness, and mechanical stability.

  15. Transparent Electrode Based on Silver Nanowires and Polyimide for Film Heater and Flexible Solar Cell.

    PubMed

    He, Xin; Duan, Feng; Liu, Junyan; Lan, Qiuming; Wu, Jianhao; Yang, Chengyan; Yang, Weijia; Zeng, Qingguang; Wang, Huafang

    2017-11-29

    Transparent, conductive, and flexible Ag nanowire (NW)-polyimide (PI) composite films were fabricated by a facile solution method. Well-dispersed Ag NWs result in percolation networks on the PI supporting layer. A series of films with transmittance values of 53-80% and sheet resistances of 2.8-16.5 Ω/sq were investigated. To further verify the practicability of the Ag NWs-PI film in optoelectronic devices, we utilized it in a film heater and a flexible solar cell. The film heater was able to generate a temperature of 58 °C at a driving voltage of 3.5 V within 20 s, indicating its potential application in heating devices that require low power consumption and fast response. The flexible solar cell based on the composite film with a transmittance value of 71% presented a power conversion efficiency of 3.53%. These successful applications proved that the fabricated Ag NWs-PI composite film is a good candidate for application in flexible optoelectronic devices.

  16. Investigation on Low Firing Copper for Front Electrode of Si-Based Solar Cell Applications.

    PubMed

    Chiang, Chen-Su; Wu, Yia-Ming; Lee, Wen-Hsi

    2018-04-01

    Solar cell is one of the most popular alternative energies. The aim of this study is to construct an ohmic contact between front electrode and Si-based solar cell by a Newly-invented low-cost paste and low temperature sintering process. The core-shell of CucoreAgshell powders were prepared for making high solid content paste, then screen printing the fine line on laser-opening H-pattern silicon substrate and applying firing process. Because the silver coverage is more than 95% and silver nanoparticles start to melt at 200 °C. The shell of nanoparticles of silver not only is used to prevent copper from oxidized, but also connected core Cu particles for enhancing the conductivity of CucoreAgshell. TEM, EDS, SEM were used to examine the microstructure of CucoreAgshell. Fourpoint probe and transmission line model were employed to analyze the sheet resistance and the specific contact resistance. The lowest specific contact resistivity is 0.005 Ωcm2, sheet resistance is 0.0138 Ω/ and the lowest resistivity of front electrode measured is 2.65 × 10-5 Ωcm when CucoreAgshell paste with 94 wt% solid content was fired at 550 °C.

  17. Carbon-Based Perovskite Solar Cells without Hole Transport Materials: The Front Runner to the Market?

    PubMed

    Chen, Haining; Yang, Shihe

    2017-06-01

    Organometal trihalide perovskite solar cells (PSCs) have garnered recent interest in the scientific community. In the past few years, they have achieved power conversion efficiencies comparable to traditional commercial solar cells (e.g., crystalline Si, CuInGaSe and CdTe) due to their low-cost of production via solution-processed fabrication techniques. However, the stability of PSCs must be addressed before their commercialization is viable. Among various kinds of PSCs, carbon-based PSCs without hole transport materials (C-PSCs) seem to be the most promising for addressing the stability issue because carbon materials are stable, inert to ion migration (which originates from perovskite and metal electrodes), and inherently water-resistant. Despite the significant development of C-PSCs since they were first reported in 2013, some pending issues still need to be addressed to increase their commercial competitiveness. Herein, recent developments in C-PSCs, including (1) device structure and working principles, (2) categorical progress of and comparison between meso C-PSCs, embedment C-PSCs and paintable PSCs, are reviewed. Promising research directions are then suggested (e.g., materials, interfaces, structure, stability measurement and scaling-up of production) to further improve and promote the commercialization of C-PSCs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. 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.

  19. Analysis of AC and DC Lighting Systems with 150-Watt Peak Solar Panel in Denpasar Based on NASA Data

    NASA Astrophysics Data System (ADS)

    Narottama, A. A. N. M.; Amerta Yasa, K.; Suwardana, I. W.; Sapteka, A. A. N. G.; Priambodo, P. S.

    2018-01-01

    Solar energy on the Earth’s surface has different magnitudes on every longitude and latitude. National Aeronautics and Space Administration (NASA) provides surface meteorology and solar energy database which can be accessed openly online. This database delivers information about Monthly Averaged Insolation Incident On A Horizontal Surface, Monthly Averaged Insolation Incident On A Horizontal Surface At Indicated GMT Times and also data about Equivalent Number Of No-Sun Or Black Days for any latitude and longitude. Therefore, we investigate the lighting systems with 150-Watt peak solar panel in Denpasar City, the capital province of Bali. Based on NASA data, we analyse the received wattage by a unit of 150-Watt peak solar panel in Denpasar City and the sustainability of 150-Watt peak solar panel to supply energy for 432-Watt hour/day AC and 360-Watt hour/day DC lighting systems using 1.2 kWh battery. The result shows that the maximum received wattage by a unit of 150-Watt peak solar panel is 0.76 kW/day in October. We concluded that the 1.2 kWh installed battery has higher capacity than the battery capacity needed in March, the month with highest no-sun days, for both AC and DC lighting systems. We calculate that the installed battery can be used to store the sustainable energy from sun needed by AC and DC lighting system for about 2.78 days and 3.51 days, consecutively.

  20. Development of Solar Research

    NASA Astrophysics Data System (ADS)

    Wittmann, Axel D.; Wolfschmidt, Gudrun; Duerbeck, Hilmar W.

    Originally based on a workshop on “Development of Solar Research”, held in Freiburg/Breisgau, this book contains articles on megalithic structures, the Nebra sky-disk, ancient sun cults, the observation of sunspots, the photography of the sun during eclipses, eclipse maps and expeditions, solar telescopes, solar physics during the Nazi era, archives of solar observations, scientific ballooning for solar research, site-testing on the Canary Islands, as well as on international cooperation.

  1. Optoelectronic and Photovoltaic Performances of Pyridine Based Monomer and Polymer Capped ZnO Dye-Sensitized Solar Cells.

    PubMed

    Singh, Satbir; Raj, Tilak; Singh, Amarpal; Kaur, Navneet

    2016-06-01

    The present research work describes the comparative analysis and performance characteristics of 4-pyridine based monomer and polymer capped ZnO dye-sensitized solar cells. The N, N-dimethyl-N4-((pyridine-4yl)methylene) propaneamine (4,monomer) and polyamine-4-pyridyl Schiff base (5, polymer) dyes were synthesized through one step condensation reaction between 4-pyridinecarboxaldehyde 1 and N, N-dimethylpropylamine 2/polyamine 3. Products obtained N, N-dimethyl-N4-((pyridine-4yl)methylene)propaneamine (4) and polyamine-4-pyridyl Schiff base (5) were purified and characterized using 1H, 13C NMR, mass, IR and CHN spectroscopy. Both the dyes 4 and 5 were further coated over ZnO nanoparticles and characterized using SEM, DLS and XRD analysis. Absorption profile and emission profile was monitored using fluorescence and UV-Vis absorption spectroscopy. A thick layer of these inbuilt dye linked ZnO nanoparticles of dyes (4) and (5) was pasted on one of the conductive side of ITO glass followed with a liquid electrolyte and counter electrode of the same conductive glass. Polyamine-4-pyridyl Schiff base polymer (5) decorated dye sensitized solar cell has shown better exciting photovoltaic properties in the form of short circuit current density (J(sc) = 6.3 mA/cm2), open circuit photo voltage (V(oc) = 0.7 V), fill factor (FF = 0.736) than monomer decorated dye sensitized solar cell. Polymer dye (5) based ZnO solar cell has shown a maximum solar power to electrical conversion efficiency of 3.25%, which is enhanced by 2.16% in case of monomer dye based ZnO solar cell under AM 1.5 sun illuminations.

  2. Enhancement of slope efficiency and output power in GaN-based vertical-cavity surface-emitting lasers with a SiO2-buried lateral index guide

    NASA Astrophysics Data System (ADS)

    Kuramoto, Masaru; Kobayashi, Seiichiro; Akagi, Takanobu; Tazawa, Komei; Tanaka, Kazufumi; Saito, Tatsuma; Takeuchi, Tetsuya

    2018-03-01

    We have achieved a high output power of 6 mW from a 441 nm GaN-based vertical-cavity surface-emitting laser (VCSEL) under continuous wave (CW) operation, by reducing both the internal loss and the reflectivity of the front cavity mirror. A preliminary analysis of the internal loss revealed an enormously high transverse radiation loss in a conventional GaN-based VCSEL without lateral optical confinement (LOC). Introducing an LOC structure enhanced the slope efficiency by a factor of 4.7, with a further improvement to a factor of 6.7 upon reducing the front mirror reflectivity. The result was a slope efficiency of 0.87 W/A and an external differential quantum efficiency of 32% under pulsed operation. A flip-chip-bonded VCSEL also exhibited a high slope efficiency of 0.64 W/A and an external differential quantum efficiency of 23% for the front-side output under CW operation. The reflectivity of the cavity mirror was adjusted by varying the number of AlInN/GaN distributed Bragg reflector pairs from 46 to 42, corresponding to reflectivity values from 99.8% to 99.5%. These results demonstrate that a combination of internal loss reduction and cavity mirror control is a very effective way of obtaining a high output GaN-based VCSEL.

  3. Quantum Dot Sensitized Solar Cells Based on Ternary Metal Oxide Nanowires

    SciTech Connect

    Wang, Wenyong; Tang, Jinke; Dahnovsky, Yuri

    In Phase I of this project we investigate quantum dot sensitized solar cells (QDSSCs) based on ternary metal oxide nanowires and study the physical and chemical mechanisms that govern device operation. Our research has the following five objectives: (1) synthesis of ternary metal oxide nanowires, (2) synthesis of QDs and exploration of non-solution based QD deposition methods, (3) physical and electro-optical characterizations of fabricated solar devices, (4) device modeling and first-principle theoretical study of transport physics, and (5) investigation of long-term stability issues of QD sensitized solar cells. In Phase II of this project our first major research goal ismore » to investigate magnetically doped quantum dots and related spin polarization effect, which could improve light absorption and suppress electron relaxation in the QDs. We will utilize both physical and chemical methods to synthesize these doped QDs. We will also study magnetically modified nanowires and introduce spin-polarized transport into QDSSCs, and inspect its impact on forward electron injection and back electron transfer processes. Our second goal is to study novel solid-state electrolytes for QDSSCs. Specifically, we will inspect a new type of polymer electrolytes based on a modified polysulfide redox couple, and examine the effect of their electrical properties on QDSSC performance. These solid-state electrolytes could also be used as filler materials for in situ sample fracturing in STM and enable cross-sectional interface examination of QD/nanowire structures. Our third research goal is to examine the interfacial properties such as energy level alignment at QD/nanowire interfaces using the newly developed Cross-sectional Scanning Tunneling Microscopy and Spectroscopy technique for non-cleavable materials. This technique allows a direct probing of band structures and alignment at device interfaces, which could generate important insight into the mechanisms that govern QDSSC

  4. Cu(In,Ga)Se2 Solar Cells with Amorphous In2O3-Based Front Contact Layers.

    PubMed

    Koida, Takashi; Ueno, Yuko; Nishinaga, Jiro; Higuchi, Hirohumi; Takahashi, Hideki; Iioka, Masayuki; Shibata, Hajime; Niki, Shigeru

    2017-09-06

    Amorphous (a-) In 2 O 3 -based front contact layers composed of transparent conducting oxide (TCO) and transparent oxide semiconductor (TOS) layers were proved to be effective in enhancing the short-circuit current density (J sc ) of Cu(In,Ga)Se 2 (CIGS) solar cells with a glass/Mo/CIGS/CdS/TOS/TCO structure, while maintaining high fill factor (FF) and open-circuit voltage (V oc ). An n-type a-In-Ga-Zn-O layer was introduced between the CdS and TCO layers. Unlike unintentionally doped ZnO broadly used as TOS layers in CIGS solar cells, the grain-boundary(GB)-free amorphous structure of the a-In-Ga-Zn-O layers allowed high electron mobility with superior control over the carrier density (N). High FF and V oc values were achieved in solar cells containing a-In-Ga-Zn-O layers with N values broadly ranging from 2 × 10 15 to 3 × 10 18 cm -3 . The decrease in FF and V oc produced by the electronic inhomogeneity of solar cells was mitigated by controlling the series resistance within the TOS layer of CIGS solar cells. In addition, a-In 2 O 3 :H and a-In-Zn-O layers exhibited higher electron mobilities than the ZnO:Al layers conventionally used as TCO layers in CIGS solar cells. The In 2 O 3 -based layers exhibited lower free carrier absorption while maintaining similar sheet resistance than ZnO:Al. The TCO and TOS materials and their combinations did not significantly change the V oc of the CIGS solar cells and the mini-modules.

  5. Solar multi-conjugate adaptive optics based on high order ground layer adaptive optics and low order high altitude correction.

    PubMed

    Zhang, Lanqiang; Guo, Youming; Rao, Changhui

    2017-02-20

    Multi-conjugate adaptive optics (MCAO) is the most promising technique currently developed to enlarge the corrected field of view of adaptive optics for astronomy. In this paper, we propose a new configuration of solar MCAO based on high order ground layer adaptive optics and low order high altitude correction, which result in a homogeneous correction effect in the whole field of view. An individual high order multiple direction Shack-Hartmann wavefront sensor is employed in the configuration to detect the ground layer turbulence for low altitude correction. Furthermore, the other low order multiple direction Shack-Hartmann wavefront sensor supplies the wavefront information caused by high layers' turbulence through atmospheric tomography for high altitude correction. Simulation results based on the system design at the 1-meter New Vacuum Solar Telescope show that the correction uniform of the new scheme is obviously improved compared to conventional solar MCAO configuration.

  6. Voltage-Load Sensitivity Matrix Based Demand Response for Voltage Control in High Solar Penetration Distribution Feeders

    SciTech Connect

    Zhu, Xiangqi; Wang, Jiyu; Mulcahy, David

    This paper presents a voltage-load sensitivity matrix (VLSM) based voltage control method to deploy demand response resources for controlling voltage in high solar penetration distribution feeders. The IEEE 123-bus system in OpenDSS is used for testing the performance of the preliminary VLSM-based voltage control approach. A load disaggregation process is applied to disaggregate the total load profile at the feeder head to each load nodes along the feeder so that loads are modeled at residential house level. Measured solar generation profiles are used in the simulation to model the impact of solar power on distribution feeder voltage profiles. Different casemore » studies involving various PV penetration levels and installation locations have been performed. Simulation results show that the VLSM algorithm performance meets the voltage control requirements and is an effective voltage control strategy.« less

  7. Development of Fe/Nb-based solar photocatalysts for water treatment: impact of different synthesis routes on materials properties.

    PubMed

    Ribeiro, Marília C M; Amorim, Camila C; Moreira, Regina F P M; Oliveira, Luiz C A; Henriques, Andréia B; Leão, Mônica M D

    2018-04-27

    Semiconductors based on Fe/Nb oxides can present both solar sensitivity and high catalytic activity. However, there is still a lack regarding the comparison between different routes to produce Fe/Nb-based solar photocatalysts and the evaluation of the impact of the synthesis operating conditions on the material properties. In this work, Fe/Nb 2 O 5 ratio, type of precipitating agent, presence/absence of washing stage, and temperature of calcination were verified to be the most relevant parameters in the synthesis by the co-precipitation method. These factors led to remarkable differences in the properties and performance of the photocatalysts produced by each distinct synthesis route. Composition, iron species present in the materials, crystallinity characteristics, and pH of the catalysts were affected, leading to different photocatalytic activities under UV-Vis light. Due to their characteristics, the synthesized materials are potential photocatalysts for application in solar processes. Graphical abstract ᅟ.

  8. Stable and null current hysteresis perovskite solar cells based nitrogen doped graphene oxide nanoribbons hole transport layer

    PubMed Central

    Kim, Jeongmo; Mat Teridi, Mohd Asri; Mohd Yusoff, Abd. Rashid bin; Jang, Jin

    2016-01-01

    Perovskite solar cells are becoming one of the leading technologies to reduce our dependency on traditional power sources. However, the frequently used component poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) has several shortcomings, such as an easily corroded indium-tin-oxide (ITO) interface at elevated temperatures and induced electrical inhomogeneity. Herein, we propose solution-processed nitrogen-doped graphene oxide nanoribbons (NGONRs) as a hole transport layer (HTL) in perovskite solar cells, replacing the conducting polymer PEDOT:PSS. The conversion efficiency of NGONR-based perovskite solar cells has outperformed a control device constructed using PEDOT:PSS. Moreover, our proposed NGONR-based devices also demonstrate a negligible current hysteresis along with improved stability. This work provides an effective route for substituting PEDOT:PSS as the effective HTL. PMID:27277388

  9. Characterization of anthocyanin based dye-sensitized organic solar cells (DSSC) and modifications based on bio-inspired ion mobility improvements

    NASA Astrophysics Data System (ADS)

    Mawyin, Jose Amador

    The worldwide electrical energy consumption will increase from currently 10 terawatts to 30 terawatts by 2050. To decrease the current atmospheric CO2 would require our civilization to develop a 20 terawatts non-greenhouse emitting (renewable) electrical power generation capability. Solar photovoltaic electric power generation is thought to be a major component of proposed renewable energy-based economy. One approach to less costly, easily manufactured solar cells is the Dye-sensitized solar cells (DSSC) introduced by Greatzel and others. This dissertation describes the work focused on improving the performance of DSSC type solar cells. In particular parameters affecting dye-sensitized solar cells (DSSC) based on anthocyanin pigments extracted from California blackberries (Rubus ursinus) and bio-inspired modifications were analyzed and solar cell designs optimized. Using off-the-shelf materials DSSC were constructed and tested using a custom made solar spectrum simulator and photoelectric property characterization. This equipment facilitated the taking of automated I-V curve plots and the experimental determination of parameters such as open circuit voltage (V OC), short circuit current (JSC), fill factor (FF), etc. This equipment was used to probe the effect of various modifications such as changes in the annealing time and composition of the of the electrode counter-electrode. Solar cell optimization schemes included novel schemes such as solar spectrum manipulation to increase the percentage of the solar spectrum capable of generating power in the DSSC. Solar manipulation included light scattering and photon upconversion. Techniques examined here focused on affordable materials such as silica nanoparticles embedded inside a TiO2 matrix. Such materials were examined for controlled scattering of visible light and optimize light trapping within the matrix as well as a means to achieve photon up-energy-conversion using the Raman effect in silica nano-particles (due

  10. Design and synthesis of chlorinated benzothiadiazole-based polymers for efficient solar energy conversion

    DOE PAGES

    Hu, Zhiming; Chen, Hui; Qu, Jianfei; ...

    2017-03-10

    Here, chlorinated benzothiadiazide based polymers with multiple chlorine atoms has been designed and synthesized for polymer solar cells with enhanced open circuit voltage up to 0.85 V. The chlorine substitution is found to significantly adjust the band gap of the polymers, and change polymer’s orientation from random morphology of chlorine free PBT4T-2OD, to mixed face-on packing of one chlorine substituted PCBT4T-2OD, and finally to edge-on of two chlorine substituted PCCBT4T-2OD. The optimized chlorinated polymer, PCBT4T-2OD with only one chlorine atom substituted on BT moiety, has been founded to achieve the highest power conversion efficiency up to 8.20% with PC 71BM,more » which is about 68% higher than that of its non-chlorine analogues.« less

  11. Ultrasonic Remove of Particle Aggregation in Carbon Based Counter Electrodes for Dye-Sensitized Solar Cells.

    PubMed

    Yang, Pan; Hu, Zi-Jun; Lin, Hong; Lai, Xin-Chun; Zhao, Xiao-Chong; Yang, Li-Jun

    2018-06-01

    Low-cost carbon materials (carbon black and graphite power) were applied as substitution of platinum (Pt) in counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). Three fabrication methods, such as ball-milled, pulp-refined, and ultrasonic-crushed, were applied to remove the particle aggregation in the carbon pastes. Then the carbon based pastes were printed on fluorine-doped transparent conducting oxide (FTO) glasses, used as the CEs for DSSCs. Under illumination of 100 mW/cm2, DSSCs with ultrasonic-crushed CEs (U-CEs) show an energy conversion efficiency of 3.57%, which reach to 65.38% of that with conventional sputtered platinum CEs (5.46%). In addition, U-CEs exhibit a higher catalytic activity and a faster charge transfer rate toward the reduction of I-3 to I-.

  12. Compact high-flux two-stage solar collectors based on tailored edge-ray concentrators

    NASA Astrophysics Data System (ADS)

    Friedman, Robert P.; Gordon, Jeffrey M.; Ries, Harald

    1995-08-01

    Using the recently-invented tailored edge-ray concentrator (TERC) approach for the design of compact two-stage high-flux solar collectors--a focusing primary reflector and a nonimaging TERC secondary reflector--we present: 1) a new primary reflector shape based on the TERC approach and a secondary TERC tailored to its particular flux map, such that more compact concentrators emerge at flux concentration levels in excess of 90% of the thermodynamic limit; and 2) calculations and raytrace simulations result which demonstrate the V-cone approximations to a wide variety of TERCs attain the concentration of the TERC to within a few percent, and hence represent practical secondary concentrators that may be superior to corresponding compound parabolic concentrator or trumpet secondaries.

  13. Design and optimization of zero-energy-consumption based solar energy residential building systems

    NASA Astrophysics Data System (ADS)

    Zheng, D. L.; Yu, L. J.; Tan, H. W.

    2017-11-01

    Energy consumption of residential buildings has grown fast in recent years, thus raising a challenge on zero energy residential building (ZERB) systems, which aim at substantially reducing energy consumption of residential buildings. Thus, how to facilitate ZERB has become a hot but difficult topic. In the paper, we put forward the overall design principle of ZERB based on analysis of the systems’ energy demand. In particular, the architecture for both schematic design and passive technology is optimized and both energy simulation analysis and energy balancing analysis are implemented, followed by committing the selection of high-efficiency appliance and renewable energy sources for ZERB residential building. In addition, Chinese classical residential building has been investigated in the proposed case, in which several critical aspects such as building optimization, passive design, PV panel and HVAC system integrated with solar water heater, Phase change materials, natural ventilation, etc., have been taken into consideration.

  14. Realization of highly efficient polymer solar cell based on PBDTTT-EFT and [71]PCBM

    NASA Astrophysics Data System (ADS)

    Bharti, Vishal; Chand, Suresh; Dutta, Viresh

    2018-04-01

    In this work, we have fabricated highly efficient polymer solar cells based on the blend of PBDTTT-EFT:PC71BM in the inverted device configuration. By using low temperature processed zinc oxide (ZnO) nanoparticles as an electron-transport layer (ETL) and 1,8-diiodooctane (DIO) as additive in chlorobenzene (CB) solvent we have achieved PCE of 9.43% with an excellent short-circuit current density (Jsc) of 17.6 mAcm-2, open circuit voltage (Voc) of 0.80 V and fill factor (FF) of 0.67. These results reveals that addition of 3% DIO additive in CB solvent improve the morphology (lower charge carrier recombination and better metal/organic semiconductor interface) and provide uniform interpenetrating networks in PBDTTT-EFT:PC71BM blend active layer.

  15. Internal transmission coefficient in charges carrier generation layer of graphene/Si based solar cell device

    SciTech Connect

    Rosikhin, Ahmad, E-mail: a.rosikhin86@yahoo.co.id; Winata, Toto, E-mail: toto@fi.itb.ac.id

    2016-04-19

    Internal transmission profile in charges carrier generation layer of graphene/Si based solar cell has been explored theoretically. Photovoltaic device was constructed from graphene/Si heterojunction forming a multilayer stuck with Si as generation layer. The graphene/Si sheet was layered on ITO/glass wafer then coated by Al forming Ohmic contact with Si. Photon incident propagate from glass substrate to metal electrode and assumed that there is no transmission in Al layer. The wavelength range spectra used in this calculation was 200 – 1000 nm. It found that transmission intensity in the generation layer show non-linear behavior and partitioned by few areas which relatedmore » with excitation process. According to this information, it may to optimize the photons absorption to create more excitation process by inserting appropriate material to enhance optical properties in certain wavelength spectra because of the exciton generation is strongly influenced by photon absorption.« less

  16. Analysis (Simulation) of Ni-63 beta-voltaic cells based on silicon solar cells

    NASA Astrophysics Data System (ADS)

    Gorbatsevich, A. A.; Danilin, A. B.; Korneev, V. I.; Magomedbekov, E. P.; Molin, A. A.

    2016-07-01

    Beta-voltaic cells based on standard silicon solar cells with bilateral coating with beta-radiation sources in the form of 63Ni isotope have been studied experimentally and by numerical simulation. The optimal parameters of the cell, including its thickness, the doping level of the substrate, the depth of the p- n junction on its front side, and the p + layer on the back side, as well as the activity of the source material, have been calculated. The limiting theoretical values of the open-circuit voltage (0.26 V), short-circuiting current (2.1 μA), the output power of the cell (0.39 μW), and the efficiency of the conversion of the radioactive energy onto the electric energy (4.8%) have been determined for a beta-source activity of 40 mCi. The results of numerical analysis have been compared with the experimental data.

  17. Quinacridone-based molecular donors for solution processed bulk-heterojunction organic solar cells.

    PubMed

    Chen, John Jun-An; Chen, Teresa L; Kim, BongSoo; Poulsen, Daniel A; Mynar, Justin L; Fréchet, Jean M J; Ma, Biwu

    2010-09-01

    New soluble quinacridone-based molecules have been developed as electron donor materials for solution-processed organic solar cells. By functionalizing the pristine pigment core of quinacridone with solubilizing alkyl chains and light absorbing/charge transporting thiophene units, i.e., bithiophene (BT) and thienylbenzo[c][1,2,5]thiadiazolethienyl (BTD), we prepared a series of multifunctional quinacridone-based molecules. These molecular donors show intense absorption in the visible spectral region, and the absorption range and intensity are well-tuned by the interaction between the quinacridone core and the incorporated thiophene units. The thin film absorption edge extends with the expansion of molecular conjugation, i.e., 552 nm for N,N'-di(2-ethylhexyl)quinacridone (QA), 592 nm for 2,9-Bis(5'-hexyl-2,2'-bithiophene)-N,N'-di(2-ethylhexyl)quinacridone (QA-BT), and 637 nm for 4-(5-hexylthiophen-2-yl)-7-(thiophen-2-yl)benzo[c][1,2,5]thiadiazole (QA-BTD). The change of molecular structure also influences the electrochemical properties. Observed from cyclic voltammetry measurements, the oxidation and reduction potentials (vs ferrocene) are 0.7 and -1.83 V for QA, 0.54 and -1.76 V for QA-BT, and 0.45 and -1.68 V for QA-BTD. Uniform thin films can be generated from both single component molecular solutions and blend solutions of these molecules with [6,6]-phenyl C70-butyric acid methyl ester (PC70BM). The blend films exhibit space-charge limited current (SCLC) hole mobilities on the order of 1×10(-4) cm(2) V(-1) S(-1). Bulk heterojunction (BHJ) solar cells using these soluble molecules as donors and PC70BM as the acceptor were fabricated. Power conversion efficiencies (PCEs) of up to 2.22% under AM 1.5 G simulated 1 sun solar illumination have been achieved and external quantum efficiencies (EQEs) reach as high as ∼45%.

  18. Microprocessing of ITO and a-Si thin films using ns laser sources

    NASA Astrophysics Data System (ADS)

    Molpeceres, C.; Lauzurica, S.; Ocaña, J. L.; Gandía, J. J.; Urbina, L.; Cárabe, J.

    2005-06-01

    Selective ablation of thin films for the development of new photovoltaic panels and sensoring devices based on amorphous silicon (a-Si) is an emerging field, in which laser micromachining systems appear as appropriate tools for process development and device fabrication. In particular, a promising application is the development of purely photovoltaic position sensors. Standard p-i-n or Schottky configurations using transparent conductive oxides (TCO), a-Si and metals are especially well suited for these applications, appearing selective laser ablation as an ideal process for controlled material patterning and isolation. In this work a detailed study of laser ablation of a widely used TCO, indium-tin-oxide (ITO), and a-Si thin films of different thicknesses is presented, with special emphasis on the morphological analysis of the generated grooves. Excimer (KrF, λ = 248 nm) and DPSS lasers (λ = 355 and λ = 1064 nm) with nanosecond pulse duration have been used for material patterning. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) techniques have been applied for the characterization of the ablated grooves. Additionally, process parametric windows have been determined in order to assess this technology as potentially competitive to standard photolithographic processes. The encouraging results obtained, with well-defined ablation grooves having thicknesses in the order of 10 µm both in ITO and in a-Si, open up the possibility of developing a high-performance double Schottky photovoltaic matrix position sensor.

  19. Correlation Length of Energy-Containing Structures in the Base of the Solar Corona

    NASA Astrophysics Data System (ADS)

    Abramenko, V.; Zank, G. P.; Dosch, A. M.; Yurchyshyn, V.

    2013-12-01

    An essential parameter for models of coronal heating and fast solar wind acceleration that relay on the dissipation of MHD turbulence is the characteristic energy-containing length of the squared velocity and magnetic field fluctuations transverse to the mean magnetic field inside a coronal hole (CH) at the base of the corona. The characteristic length scale defines directly the heating rate. Rather surprisingly, almost nothing is known observationally about this critical parameter. Currently, only a very rough estimate of characteristic length was obtained based on the fact that the network spacing is about 30000 km. We attempted estimation of this parameter from observations of photospheric random motions and magnetic fields measured in the photosphere inside coronal holes. We found that the characteristic length scale in the photosphere is about 600-2000 km, which is much smaller than that adopted in previous models. Our results provide a critical input parameter for current models of coronal heating and should yield an improved understanding of fast solar wind acceleration. Fig. 1-- Plotted is the natural logarithm of the correlation function of the transverse velocity fluctuations u^2 versus the spatial lag r for the two CHs. The color code refers to the accumulation time intervals of 2 (blue), 5 (green), 10 (red), and 20 (black) minutes. The values of the Batchelor integral length λ the correlation length ς and the e-folding length L in km are shown. Fig. 2-- Plot of the natural logarithm of the correlation function of magnetic fluctuations b^2 versus the spatial lag r. The insert shows this plot with linear axes.

  20. Parameters influencing the deposition of methylammonium lead halide iodide in hole conductor free perovskite-based solar cells

    NASA Astrophysics Data System (ADS)

    Cohen, Bat-El; Gamliel, Shany; Etgar, Lioz

    2014-08-01

    Perovskite is a promising light harvester for use in photovoltaic solar cells. In recent years, the power conversion efficiency of perovskite solar cells has been dramatically increased, making them a competitive source of renewable energy. An important parameter when designing high efficiency perovskite-based solar cells is the perovskite deposition, which must be performed to create complete coverage and optimal film thickness. This paper describes an in-depth study on two-step deposition, separating the perovskite deposition into two precursors. The effects of spin velocity, annealing temperature, dipping time, and methylammonium iodide concentration on the photovoltaic performance are studied. Observations include that current density is affected by changing the spin velocity, while the fill factor changes mainly due to the dipping time and methylammonium iodide concentration. Interestingly, the open circuit voltage is almost unaffected by these parameters. Hole conductor free perovskite solar cells are used in this work, in order to minimize other possible effects. This study provides better understanding and control over the perovskite deposition through highly efficient, low-cost perovskite-based solar cells.