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1

Photovoltaic cells employing zinc phosphide  

DOEpatents

A photovoltaic cell having a zinc phosphide absorber. The zinc phosphide can be a single or multiple crystal slice or a thin polycrystalline film. The cell can be a Schottky barrier, heterojunction or homojunction device. Methods for synthesizing and crystallizing zinc phosphide are disclosed as well as a method for forming thin films.

Barnett, Allen M. (Newark, DE); Catalano, Anthony W. (Wilmington, DE); Dalal, Vikram L. (Newark, DE); Masi, James V. (Wilbraham, MA); Meakin, John D. (Newark, DE); Hall, Robert B. (Newark, DE)

1984-01-01

2

Performance enhancement of a graphene-zinc phosphide solar cell using the electric field-effect.  

PubMed

The optical transparency and high electron mobility of graphene make it an attractive material for photovoltaics. We present a field-effect solar cell using graphene to form a tunable junction barrier with an Earth-abundant and low cost zinc phosphide (Zn3P2) thin-film light absorber. Adding a semitransparent top electrostatic gate allows for tuning of the graphene Fermi level and hence the energy barrier at the graphene-Zn3P2 junction, going from an ohmic contact at negative gate voltages to a rectifying barrier at positive gate voltages. We perform current and capacitance measurements at different gate voltages in order to demonstrate the control of the energy barrier and depletion width in the zinc phosphide. Our photovoltaic measurements show that the efficiency conversion is increased 2-fold when we increase the gate voltage and the junction barrier to maximize the photovoltaic response. At an optimal gate voltage of +2 V, we obtain an open-circuit voltage of V oc = 0.53 V and an efficiency of 1.9% under AM 1.5 1-sun solar illumination. This work demonstrates that the field effect can be used to modulate and optimize the response of photovoltaic devices incorporating graphene. PMID:25058004

Vazquez-Mena, Oscar; Bosco, Jeffrey P; Ergen, O; Rasool, Haider I; Fathalizadeh, Aidin; Tosun, Mahmut; Crommie, Michael; Javey, Ali; Atwater, Harry A; Zettl, Alex

2014-08-13

3

Indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

The direction for InP solar cell research; reduction of cell cost; increase of cell efficiency; measurements needed to better understand cell performance; n/p versus p/n; radiation effects; major problems in cell contacting; and whether the present level of InP solar cell research in the USA should be maintained, decreased, or increased were considered.

Weinberg, Irving

1991-01-01

4

Performance Enhancement of a Graphene-Zinc Phosphide Solar Cell Using the Electric Field-Effect  

E-print Network

implementation at lower costs, such as zinc phosphide (Zn3P2), copper zinc tin sulfide (CZTS), cuprous oxide (Cu2O), and iron sulfide (FeS2).4 However, the lack of doping processes necessary to form homojuntions. This design has been used to build a graphene-Si transistor (barristor)12 and a graphene-organic thin film

Javey, Ali

5

PLD growth of thin film Zinc Phosphide  

NASA Astrophysics Data System (ADS)

The development of efficient, low cost solar cells to meet society's growing energy needs has triggered tremendous interest in developing photovoltaics formed from earth abundant materials. Zinc phosphide (Zn3P2) is a promising earth abundant absorber layer for photovoltaic energy conversion with a nearly ideal band gap (1.5eV) and a large absorption coefficient of 10^4/cm. In this work we examine the growth parameters, electrical and optical properties of thin film zinc phosphide produced using pulsed laser deposition (PLD) from a zinc phosphide target at laser fluencies ranging from 1-3 J/cm2. For the laser fluences explored, highly resistive amorphous zinc phosphide thin films were produced with a band gap of approximately 1.7 eV. The thin films could be transformed from amorphous to polycrystalline zinc phosphide by annealing at 400C for 15mins in a N2 atmosphere. High resolution X-ray photoelectron spectroscopy (XPS) is used to examine the binding energies of Zn 2p3/2 and Phosphorous 2p3/2 signals and are in the range of 1021.6 eV and 127.5 eV. Energy Dispersive X-ray Spectroscopy (EDAX) revealed that the Zn3P2 thin films are nearly stoichiometric in composition. Hall mobility in these materials and Zn3P2/ZnS hetrojunction solar cell performance will be discussed.

Vaddi, Rajesh; Vasekar, Parag; Westgate, Charles; White, Bruce

2013-03-01

6

Determination of series resistance of indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

The series resistance of a solar cell is an important parameter, which must be minimized to achieve high cell efficiencies. The cell series resistance is affected by the starting material, its design, and processing. The theoretical approach proposed by Jia, et. al., is used to calculate the series resistance of indium phosphide solar cells. It is observed that the theoretical approach does not predict the series resistance correctly in all cases. The analysis was modified to include the use of effective junction ideality factor. The calculated results were compared with the available experimental results on indium phosphide solar cells processed by different techniques. It is found that the use of process dependent junction ideality factor leads to better estimation of series resistance. An accurate comprehensive series resistance model is warranted to give proper feedback for modifying the cell processing from the design state.

Jain, Raj K.; Weinberg, Irving

1991-01-01

7

Indium phosphide solar cells for laser power beaming applications  

NASA Technical Reports Server (NTRS)

Lasers can be used to transmit power to photovoltaic cells. Solar cell efficiencies are enhanced significantly under monochromatic light, and therefore a laser beam of proper wavelength could be a very effective source of illumination for a solar array operating at very high efficiencies. This work reviews the modeling studies made on indium phosphide solar cells for such an application. These cells are known to be very radiation resistant and have a potential for high efficiency. Effects of cell series resistance, laser intensity, and temperature on cell performance have been discussed.

Jain, Raj K.; Landis, Geoffrey A.

1992-01-01

8

Zinc Phosphide Poisoning  

PubMed Central

Zinc phosphide has been used widely as a rodenticide. Upon ingestion, it gets converted to phosphine gas in the body, which is subsequently absorbed into the bloodstream through the stomach and the intestines and gets captured by the liver and the lungs. Phosphine gas produces various metabolic and nonmetabolic toxic effects. Clinical symptoms are circulatory collapse, hypotension, shock symptoms, myocarditis, pericarditis, acute pulmonary edema, and congestive heart failure. In this case presentation, we aim to present the intensive care process and treatment resistance of a patient who ingested zinc phosphide for suicide purposes. PMID:25101186

Do?an, Erdal; Gzel, Abdulmenap; ifti, Taner; Aycan, ?lker; etin, Bedri; Kavak, Gnl lmez

2014-01-01

9

Rational Design of Zinc Phosphide Heterojunction Photovoltaics  

E-print Network

. Dr. Greg Kimball initially started the zinc phosphide solar project and the knowledge he contributed: Joseph Beardsley (Kratos XPS), Emily Warmman (HRXRD), Bruce Brunswig (MMRC), Ryan Briggs and Stan Berkos

Winfree, Erik

10

Calculated performance of indium phosphide solar cells under monochromatic illumination  

SciTech Connect

The performance of a high-efficiency indium phosphide n[sup +]p solar cell under monochromatic illumination has been modeled. The cell modeling of this experimental device gives the peak efficiency in excess of 44% at 0.87 [mu]m and 25 C. The effect of cell series resistance on its performance has also been studied. Calculated efficiencies for an optimized InP cell are in excess of 50% in the wavelength band of 0.75--0.925 [mu]m. The calculations of conversion efficiency versus source wavelength for InP solar cells are compared to other solar cell materials at a source illumination of 1 W/cm[sup 2].

Jain, R.K. (NASA Lewis Research Center, Cleveland, OH (United States))

1993-10-01

11

Recent developments in indium phosphide space solar cell research  

NASA Technical Reports Server (NTRS)

Recent developments and progress in indium phosphide solar cell research for space application are reviewed. Indium phosphide homojunction cells were fabricated in both the n+p and p+n configurations with total area efficiencies of 17.9 and 15.9% (air mass 0 and 25 C) respectively. Organometallic chemical vapor deposition, liquid phase epitaxy, ion implantation and diffusion techniques were employed in InP cell fabrication. A theoretical model of a radiation tolerant, high efficiency homojunction cell was developed. A realistically attainable AMO efficiency of 20.5% was calculated using this model with emitter and base doping of 6 x 10 to the 17th power and 5 x 10 the the 16th power/cu cm respectively. Cells of both configurations were irradiated with 1 MeV electrons and 37 MeV protons. For both proton and electron irradiation, the n+p cells are more radiation resistant at higher fluences than the p+n cells. The first flight module of four InP cells was assembled for the Living Plume Shield III satellite.

Brinker, David J.; Weinberg, Irving

1987-01-01

12

Indium Phosphide Window Layers for Indium Gallium Arsenide Solar Cells  

NASA Technical Reports Server (NTRS)

Window layers help in reducing the surface recombination at the emitter surface of the solar cells resulting in significant improvement in energy conversion efficiency. Indium gallium arsenide (In(x)Ga(1-x)As) and related materials based solar cells are quite promising for photovoltaic and thermophotovoltaic applications. The flexibility of the change in the bandgap energy and the growth of InGaAs on different substrates make this material very attractive for multi-bandgap energy, multi-junction solar cell approaches. The high efficiency and better radiation performance of the solar cell structures based on InGaAs make them suitable for space power applications. This work investigates the suitability of indium phosphide (InP) window layers for lattice-matched In(0.53)Ga(0.47)As (bandgap energy 0.74 eV) solar cells. We present the first data on the effects of the p-type InP window layer on p-on-n lattice-matched InGaAs solar cells. The modeled quantum efficiency results show a significant improvement in the blue region with the InP window. The bare InGaAs solar cell performance suffers due to high surface recombination velocity (10(exp 7) cm/s). The large band discontinuity at the InP/InGaAs heterojunction offers a great potential barrier to minority carriers. The calculated results demonstrate that the InP window layer effectively passivates the solar cell front surface, hence resulting in reduced surface recombination and therefore, significantly improving the performance of the InGaAs solar cell.

Jain, Raj K.

2005-01-01

13

Indium phosphide space solar cell research: Where we are and where we are going  

NASA Technical Reports Server (NTRS)

Indium phosphide is considered to be a strong contender for many photovoltaic space applications because of its radiation resistance and its potential for high efficiency. An overview of recent progress is presented, and possible future research directions for indium phosphide space solar cells are discussed. The topics considered include radiation damage studies and space flight experiments.

Jain, R. K.; Flood, D. J.; Weinberg, Irving

1995-01-01

14

Progress in indium phosphide solar cell research  

NASA Technical Reports Server (NTRS)

Progress, dating from the start of the Lewis program, is reviewed emphasizing processing techniques which have achieved the highest efficiencies in a given year. To date, the most significant achievement has been attainment of AM0 total area efficiencies approaching 19 percent. Although closed tube diffusion is not considered to be an optimum process, reasonably efficient 2cm x 2cm and 1cm x 2cm InP cells have been produced in quantity by this method with a satellite to be launched in 1990 using these cells. Proton irradiation of these relatively large area cells indicates radiation resistance comparable to that previously reported for smaller InP cells. A similar result is found for the initial proton irradiations of ITO/InP cells processed by D. C. sputtering. With respect to computer modelling, a comparison of n/p homojunction InP and GaAs cells of identical geometries and dopant concentrations has confirmed the superior radiation resistance of InP cells under 1 MeV electron irradiations.

Weinberg, Irving; Swartz, Clifford K.; Hart, R. E., Jr.

1989-01-01

15

Optimal design study of high efficiency indium phosphide space solar cells  

NASA Technical Reports Server (NTRS)

Recently indium phosphide solar cells have achieved beginning of life AMO efficiencies in excess of 19 pct. at 25 C. The high efficiency prospects along with superb radiation tolerance make indium phosphide a leading material for space power requirements. To achieve cost effectiveness, practical cell efficiencies have to be raised to near theoretical limits and thin film indium phosphide cells need to be developed. The optimal design study is described of high efficiency indium phosphide solar cells for space power applications using the PC-1D computer program. It is shown that cells with efficiencies over 22 pct. AMO at 25 C could be fabricated by achieving proper material and process parameters. It is observed that further improvements in cell material and process parameters could lead to experimental cell efficiencies near theoretical limits. The effect of various emitter and base parameters on cell performance was studied.

Jain, Raj K.; Flood, Dennis J.

1990-01-01

16

Comparative performance of diffused junction indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

A comparison is made between indium phosphide solar cells whose p-n junctions were processed by open tube capped diffusion, and closed tube uncapped diffusion, of sulfur into Czochralski grown p-type substrates. Air mass zero, total area, efficiencies ranged from 10 to 14.2 percent, the latter value attributed to cells processed by capped diffusion. The radiation resistance of these latter cells was slightly better, under 1 MeV electron irradiation. However, rather than being process dependent, the difference in radiation resistance could be attributed to the effects of increased base dopant concentration. In agreement with previous results, both cells exhibited radiation resistance superior to that of gallium arsenide. The lowest temperature dependency of maximum power was exhibited by the cells prepared by open tube capped diffusion. Contrary to previous results, no correlation was found between open circuit voltage and the temperature dependency of Pmax. It was concluded that additional process optimization was necessary before concluding that one process was better than another.

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.; Ghandhi, S. K.; Borrego, J. M.; Parat, K. K.

1987-01-01

17

Indium phosphide solar cells - Recent developments and estimated performance in space  

NASA Technical Reports Server (NTRS)

The current status of indium phosphide solar cell research is reviewed. In the NASA research program, efficiencies of 18.8 percent were achieved for standard n/p homojunction InP cells while 17 percent was achieved for ITO/InP cells processed by sputtering n-type indium tin oxide onto p-type indium phosphide. The latter represents a cheaper, simpler processing alternative. Computer modeling calculations indicate that efficiencies of over 21 percent are feasible. Relatively large area cells are produced in Japan with a maximum efficiency of 16.6 percent.

Weinberg, Irving; Brinker, David J.

1990-01-01

18

Effect of InAlAs window layer on the efficiency of indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

Indium phosphide (InP) solar cell efficiencies are limited by surface recombination. The effect of a wide-bandgap lattice-matched indium aluminum arsenide (In0.52Al0.48As) window layer on the performance of InP solar cells was investigated using a numerical code PC-1D. The p(+)n InP solar cell performance improves significantly with the use of a window layer. No improvement is seen for n(+)p InP cells. Cell results are explained by the band diagram of the heterostructure and the conduction-band energy discontinuity. The calculated I-V and internal quantum efficiency results clearly demonstrate that In0.52Al0.48As is a promising candidate as a window layer material for p(+)n InP solar cells.

Jain, R. K.; Landis, G. A.

1991-01-01

19

Effect of InAlAs window layer on efficiency of indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

Indium phosphide (InP) solar cell efficiencies are limited by surface recombination. The effect of a wide bandgap, lattice-matched indium aluminum arsenide (In(0.52)Al(0.48)As) window layer on the performance of InP solar cells was investigated by using the numerical code PC-1D. The p(+)n InP solar cell performance improved significantly with the use of the window layer. No improvement was seen for the n(+)p InP cells. The cell results were explained by the band diagram of the heterostructure and the conduction band energy discontinuity. The calculated current voltage and internal quantum efficiency results clearly demonstrated that In(0.52)Al(0.48)As is a very promising candidate for a window layer material for p(+)n InP solar cells.

Jain, Raj K.; Landis, Geoffrey A.

1992-01-01

20

Comparative radiation resistance, temperature dependence and performance of diffused junction indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

Indium phosphide solar cells whose p-n junctions were processed by the open tube capped diffusion and by the closed tube uncapped diffusion of sulfur into Czochralski-grown p-type substrates are compared. Differences found in radiation resistance were attributed to the effects of increased base dopant concentration. Both sets of cells showed superior radiation resistance to that of gallium arsenide cells, in agreement with previous results. No correlation was, however, found between the open-circuit voltage and the temperature dependence of the maximum power.

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.; Ghandhi, S. K.; Borrego, J. M.

1987-01-01

21

Effect of emitter parameter variation on the performance of heteroepitaxial indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

Metalorganic chemical-vapor-deposited heteroepitaxial indium phosphide (InP) solar cell experimental results were simulated by using a PC-1D computer model. The effect of emitter parameter variation on the performance of n(+)/p/p(+) heteroepitaxial InP/GaAs solar cell was presented. The thinner and lighter doped emitters were observed to offer higher cell efficiencies. The influence of emitter thickness and minority carrier diffusion length on the cell efficiency with respect to dislocation density was studied. Heteroepitaxial cells with efficiencies similar to present day homojunction InP efficiencies (greaater than 16 percent AM0) were shown to be attainable if a dislocation density lower than 10(exp 6)/sq cm could be achieved. A realistic optimized design study yielded InP solar cells of over 22 percent AM0 efficiency at 25 C.

Jain, R. K.; Flood, D. J.

1990-01-01

22

Effect of emitter parameter variation on the performance of heteroepitaxial indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

Metallorganic chemical-vapor-deposited heteroepitaxial indium phosphide (InP) solar cell experimental results were simulated by using a PC-1D computer model. The effect of emitter parameter variation on the performance of n(+)/p/p(+) heteroepitaxial InP/GaAs solar cell was presented. The thinner and lighter doped emitters were observed to offer higher cell efficiencies. The influence of emitter thickness and minority carrier diffusion length on the cell efficiency with respect to dislocation density was studied. Heteroepitaxial cells with efficiencies similar to present day homojunction InP efficiencies (greater than 16 percent AMO) were shown to be attainable if a dislocation density lower than 10(exp 6)/sq cm could be achieved. A realistic optimized design study yielded InP solar cells of over 22 percent AMO efficiency at 25 C.

Jain, Raj K.; Flood, Dennis J.

1990-01-01

23

40 CFR 180.284 - Zinc phosphide; tolerances for residues.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Zinc phosphide; tolerances for residues...FOOD Specific Tolerances 180.284 Zinc phosphide; tolerances for residues...resulting from the use of the rodenticide zinc phosphide in or on the raw...

2012-07-01

24

40 CFR 180.284 - Zinc phosphide; tolerances for residues.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Zinc phosphide; tolerances for residues...FOOD Specific Tolerances 180.284 Zinc phosphide; tolerances for residues...resulting from the use of the rodenticide zinc phosphide in or on the raw...

2011-07-01

25

40 CFR 180.284 - Zinc phosphide; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Zinc phosphide; tolerances for residues...FOOD Specific Tolerances 180.284 Zinc phosphide; tolerances for residues...resulting from the use of the rodenticide zinc phosphide in or on the raw...

2013-07-01

26

40 CFR 180.284 - Zinc phosphide; tolerances for residues.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Zinc phosphide; tolerances for residues...FOOD Specific Tolerances 180.284 Zinc phosphide; tolerances for residues...resulting from the use of the rodenticide zinc phosphide in or on the raw...

2014-07-01

27

Modelling and design of high performance indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

A first principles pn junction device model has predicted new designs for high voltage, high efficiency InP solar cells. Measured InP material properties were applied and device parameters (thicknesses and doping) were adjusted to obtain optimal performance designs. Results indicate that p/n InP designs will provide higher voltages and higher energy conversion efficiencies than n/p structures. Improvements to n/p structures for increased efficiency are predicted. These new designs exploit the high absorption capabilities, relatively long diffusion lengths, and modest surface recombination velocities characteristic of InP. Predictions of performance indicate achievable open-circuit voltage values as high as 943 mV for InP and a practical maximum AM0 efficiency of 22.5 percent at 1 sun and 27 C. The details of the model, the optimal InP structure and the effect of individual parameter variations on device performance are presented.

Rhoads, Sandra L.; Barnett, Allen M.

1989-01-01

28

Indium phosphide solar cells: status and prospects for use in space  

NASA Technical Reports Server (NTRS)

The current status of indium phosphide cell research is reviewed and state of the art efficiencies compared to those of GaAs and Si. It is shown that the radiation resistance of InP cells is superior to that of either GaAs or Si under 1 MeV electron and 10 MeV proton irradiation. Using lightweight blanket technology, a SEP array structure and projected cell efficiencies, array specific powers are obtained for all three cell types. Array performance is calculated as a function of time in orbit. The results indicate that arrays using InP cells can outperform those using GaAs or Si in orbits where radiation is a significant cell degradation factor. It is concluded that InP solar cells are excellent prospects for future use in the space radiation environment.

Weinberg, I.; Brinker, D. J.

1986-01-01

29

High-efficiency indium tin oxide/indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

Improvements in the performance of indium tin oxide (ITO)/indium phosphide solar cells have been realized by the dc magnetron sputter deposition of n-ITO onto an epitaxial p/p(+) structure grown on commercial p(+) bulk substrates. The highest efficiency cells were achieved when the surface of the epilayer was exposed to an Ar/H2 plasma before depositing the bulk of the ITO in a more typical Ar/O2 plasma. With H2 processing, global efficiencies of 18.9 percent were achieved. It is suggested that the excellent performance of these solar cells results from the optimization of the doping, thickness, transport, and surface properties of the p-type base, as well as from better control over the ITO deposition procedure.

Li, X.; Wanlass, M. W.; Gessert, T. A.; Emery, K. A.; Coutts, T. J.

1989-01-01

30

A review of indium phosphide space solar cell fabrication technology  

NASA Technical Reports Server (NTRS)

A review of the status of InP cell efficiency and of approaches to the reduction of cell cost is presented. The use of heteroepitaxial techniques such as InP-on-GaAs and InP-on-Si is discussed along with the use of chemical and mechanical techniques for removal and recovery of the substrate. The efficiency ultimately obtainable with designs made possible by such an approach is calculated.

Spitzer, M. B.; Dingle, B.; Dingle, J.; Morrison, R.

1990-01-01

31

Forward-biased current annealing of radiation degraded indium phosphide and gallium arsenide solar cells  

NASA Technical Reports Server (NTRS)

The preliminary results of a novel approach to low-temperature annealing of previously irradiated indium phosphide and gallium arsenide solar cells are reported. The technique is based on forward-biased current annealing. The two types of III-V solar cells were irradiated with 1-MeV electrons to a fluence level of (1-10) x 10 to the 14th electrons/sq cm. Several annealing attempts were made, varying all conditions. Optimum annealing was achieved when cells were injected with minority currents at a constant 90 C. The current density for each type of cell was also determined. Significant recovery of degraded parameters was achieved in both cases. However, the InP cell recovery notably exceeded the recovery in GaAs cells. The recovery is thought to be caused by current-stimulated reordering of the radiator-induced displacement damage. Both types of cell were then subjected to several cycles of irradiation and annealing. The results were also very promising. The significant recovery of degraded cell parameters at low temperature might play a major role in considerably extending the end of life of future spacecraft.

Michael, Sherif; Cypranowski, Corinne; Anspaugh, Bruce

1990-01-01

32

Diffusion length variation in 0.5- and 3-MeV-proton-irradiated, heteroepitaxial indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

Indium phosphide (InP) solar cells are more radiation resistant than gallium arsenide (GaAs) and silicon (Si) solar cells, and their growth by heteroepitaxy offers additional advantages leading to the development of light weight, mechanically strong, and cost-effective cells. Changes in heteroepitaxial InP cell efficiency under 0.5- and 3-MeV proton irradiations have been explained by the variation in the minority-carrier diffusion length. The base diffusion length versus proton fluence was calculated by simulating the cell performance. The diffusion length damage coefficient, K(sub L), was also plotted as a function of proton fluence.

Jain, Raj K.; Weinberg, Irving; Flood, Dennis J.

1993-01-01

33

Diphacinone and zinc phosphide toxicity in a flock of Peafowl.  

PubMed

Toxicity probably due to a combination of diphacinone and zinc phosphide was diagnosed in a flock of peafowl, in which 35 birds in a flock of 80 died over a span of 10 days without any apparent clinical signs. Chickens and guinea fowl, 30 each on the same premises, were not affected. Plastic tubes containing diphacinone and zinc phosphide were used on the premises to control ground squirrels. Most of the six dead peafowl, which ranged in age from 6 months to 4 years, had an accumulation of serosanguinous fluid in the abdominal cavity, semi-clotted blood over the liver lobes, increased pericardial fluid, and enlarged and pale kidneys. Pellets of diphacinone and zinc phosphide were found in the crop and gizzard contents from most of the birds. Microscopically, most of the birds had mild to moderate centrolobular degeneration of hepatocytes and multifocal degeneration of myofibres in the heart with infiltration by a few mononuclear cells. Acute nephrosis and mucosal oedema in the oesophagus and crop were also observed. Toxicological analysis of the crop and gizzard contents revealed the presence of diphacinone and phosphine gas, and analysis of the crop contents from two birds for heavy metals revealed zinc levels of up to 6600 parts/10 6 . It was suspected that only the peafowl and not the chickens and guinea fowl were affected because peafowl, with their longer necks, were able to reach into the plastic tubes and eat the pellets. PMID:19184953

Shivaprasad, H L; Galey, F

2001-12-01

34

A numerical simulation study of gallium-phosphide/silicon heterojunction passivated emitter and rear solar cells  

NASA Astrophysics Data System (ADS)

The performance of passivated emitter and rear (PERC) solar cells made of p-type Si wafers is often limited by recombination in the phosphorus-doped emitter. To overcome this limitation, a realistic PERC solar cell is simulated, whereby the conventional phosphorus-doped emitter is replaced by a thin, crystalline gallium phosphide (GaP) layer. The resulting GaP/Si PERC cell is compared to Si PERC cells, which have (i) a standard POCl3 diffused emitter, (ii) a solid-state diffused emitter, or (iii) a high efficiency ion-implanted emitter. The maximum efficiencies for these realistic PERC cells are between 20.5% and 21.2% for the phosphorus-doped emitters (i)-(iii), and up to 21.6% for the GaP emitter. The major advantage of this GaP hetero-emitter is a significantly reduced recombination loss, resulting in a higher Voc. This is so because the high valence band offset between GaP and Si acts as a nearly ideal minority carrier blocker. This effect is comparable to amorphous Si. However, the GaP layer can be contacted with metal fingers like crystalline Si, so no conductive oxide is necessary. Compared to the conventional PERC structure, the GaP/Si PERC cell requires a lower Si base doping density, which reduces the impact of the boron-oxygen complexes. Despite the lower base doping, fewer rear local contacts are necessary. This is so because the GaP emitter shows reduced recombination, leading to a higher minority electron density in the base and, in turn, to a higher base conductivity.

Wagner, Hannes; Ohrdes, Tobias; Dastgheib-Shirazi, Amir; Puthen-Veettil, Binesh; Knig, Dirk; Altermatt, Pietro P.

2014-01-01

35

Simulation of high-efficiency n[sup +]p indium phosphide solar cell results and future improvements  

SciTech Connect

A simulation of the highest efficiency (19.1% AM0) n[sup +]p indium phosphide (InP) solar cell was made using a computer code PC-1D in order to understand it and suggest future improvements to it. Available cell design and process data was used in the simulation. Minority carrier diffusion lengths in the emitter and base have been varied to match the experimental cell I-V characteristics with the calculated results. To further understand and improve the InP cell efficiency, simulations were performed using improved values of cell material and process parameters. The authors show that the efficiency of this cell could be increased to more than 23% AM0 by incorporating the suggested cell material, design and process improvements. At these high efficiencies InP cell technology will be very attractive for space use.

Jain, R.K.; Flood, D.J. (NASA Lewis Research Center, Cleveland, OH (United States))

1994-12-01

36

Effect of dislocations on the open-circuit voltage, short-circuit current and efficiency of heteroepitaxial indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

Excellent radiation resistance of indium phosphide solar cells makes them a promising candidate for space power applications, but the present high cost of starting substrates may inhibit their large scale use. Thin film indium phosphide cells grown on Si or GaAs substrates have exhibited low efficiencies, because of the generation and propagation of large number of dislocations. Dislocation densities were calculated and its influence on the open circuit voltage, short circuit current, and efficiency of heteroepitaxial indium phosphide cells was studied using the PC-1D. Dislocations act as predominant recombination centers and are required to be controlled by proper transition layers and improved growth techniques. It is shown that heteroepitaxial grown cells could achieve efficiencies in excess of 18 percent AMO by controlling the number of dislocations. The effect of emitter thickness and surface recombination velocity on the cell performance parameters vs. dislocation density is also studied.

Jain, Raj K.; Flood, Dennis J.

1990-01-01

37

Core-Shell Nanopillar Array Solar Cells using Cadmium Sulfide Coating on Indium Phosphide Nanopillars  

E-print Network

tandem solar cell with 10.6% power conversion efficiency. ,picture of the power conversion efficiency of solar cells,solar cell under light. Source: National Instruments [57] The final power conversion efficiency (

Tu, Bor-An Clayton

2013-01-01

38

Anthraquinone repellent to reduce take of non-target birds from zinc phosphide rodenticide applications  

Microsoft Academic Search

We evaluated anthraquinone as an avian repellent to reduce take of non-target birds from zinc phosphide rodenticide applications. We observed zero mortalities and no overt signs of zinc phosphide toxicosis among 20 Canada geese (Branta canadensis), 24 horned larks (Eremophila alpestris), and 47 ring-necked pheasants (Phasianus colchicus) offered baits treated with 1% or 2% anthraquinone and 2% zinc phosphide (target

Scott J. Werner; Shelagh K. Tupper; Susan E. Pettit; James C. Carlson; George M. Linz

39

Lattice-mismatched In(0.40)Al(0.60)As window layers for indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

The efficiency of indium phosphide (InP) solar cells is limited by its high surface recombination velocity (approximately 10(exp 7) cm/s). This might be reduced by a wide-bandgap window layer. The performance of InP solar cells with wide-bandgap (1.8 eV) lattice-mismatched In(0.40)Al(0.60)As as a window layer was calculated. Because the required window layer thickness is less than the critical layer thickness, growth of strained (pseudomorphic) layers without interfacial misfit dislocations should be possible. Calculations using the PC-lD numerical code showed that the efficiencies of baseline and optimized p(+)n (p-on-n) cells are increased to more than 22 and 24 percent, (air mass zero (AMO), 25 C), respectively for a lattice-mismatched In(0.40)Al(0.60)As window layer of 10-nm thickness. Currently, most cell development work has been focused on n(+)p (n-on-p) structures although comparatively little improvement has been found for n(+)p cells.

Jain, Raj K.; Landis, Geoffrey A.; Wilt, David M.; Flood, Dennis J.

1993-01-01

40

Indium phosphide solar cell research in the United States: Comparison with non-photovoltaic sources  

NASA Technical Reports Server (NTRS)

Highlights of the InP solar cell research program are presented. Homojunction cells with efficiencies approaching 19 percent are demonstrated, while 17 percent is achieved for ITO/InP cells. The superior radiation resistance of the two latter cell configurations over both Si and GaAs cells has been shown. InP cells aboard the LIPS3 satellite show no degradation after more than a year in orbit. Computed array specific powers are used to compare the performance of an InP solar cell array to solar dynamic and nuclear systems.

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.

1989-01-01

41

Cadmium zinc telluride solar cells by close spaced sublimation  

Microsoft Academic Search

Cadmium Zinc Telluride (CdxZn1-xTe or CZT) is a ternary semiconductor with a tunable bandgap of 1.44-2.26 eV. Solar cells with efficiencies of 20% or higher can be achieved by using a tandem solar cell structure which consists of a top cell and a bottom cell connected in series. In this kind of a structure, the light passes through the top

Madhan Raj Ramalingam

2004-01-01

42

Influence of the Dislocation Density on the Performance of Heteroepitaxial Indium Phosphide Solar Cells  

NASA Technical Reports Server (NTRS)

Calculations are made to study the dependence of heteroepitaxial InP solar-cell efficiency on dislocation density. Effects of surface recombination velocity and cell emitter thickness are considered. Calculated results are compared with the available experimental results on representative InP solar cells. It is shown that heteroepitaxial InP cells with over 20 percent AM0 efficiency could be fabricated if dislocations are reduced to less than 100,000/sq cm.

Jain, R. K.; Flood, D. J.

1991-01-01

43

Theoretical modeling, near-optimum design and predicted performance of n(+)pp(+) and p(+)nn(+) indium phosphide homojunction solar cells  

NASA Technical Reports Server (NTRS)

Using a detailed simulation model of p(+)nn(+) and n(+)pp(+) indium phosphide (InP) homojunction solar cells, extensive parametric variation computer simulation runs are conducted to help arrive at near-optimum designs of these two solar cell configurations. Values of all the geometrical and material parameters corresponding to the near-optimal designs of both these configurations are presented. For each configuration, results are given for parametric variation runs showing how the performance parameters JSC, VOC, and eta vary with each of the cell parameters for the near-optimally designed cell.

Goradia, Chandra; Thesling, William; Weinberg, Irving

1991-01-01

44

Three-dimensional numerical modeling of indium phosphide Point-Contact Solar Cells  

NASA Technical Reports Server (NTRS)

The Point-Contact Solar Cell (PCSC) geometry has proven very effective for silicon cells. To date, it has not been implemented in III-V materials. In addition, modeling such a geometry is very difficult because of its three-dimensional nature. We have developed a three-dimensional finite element modeling code (FIESTA ROC). In this paper, we present results from a three-dimensional modeling study of InP point-contact solar cells.

Clark, Ralph O.

1992-01-01

45

Indium phosphide solar cell research in the US: Comparison with nonphotovoltaic sources  

NASA Technical Reports Server (NTRS)

Highlights of the InP solar cell research program are presented. Homojunction cells with AMO efficiences approaching 19 percent were demonstrated while 17 percent was achieved for indium tin oxide (ITO)/InP cells. The superior radiation resistance of these latter two cell configurations over both Si and GaAs were demonstrated. InP cells on board the LIPS III satellite show no degradation after more than a year in orbit. Computer modeling calculations were directed toward radiation damage predictions and the specification of concentrator cell parameters. Computed array specific powers, for a specific orbit, are used to compare the performance of an InP solar cell array to solar dynamic and nuclear systems.

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.

1989-01-01

46

Naval Research Laboratory's programs in advanced indium phosphide solar cell development  

NASA Technical Reports Server (NTRS)

The Naval Research Laboratory (NRL) has been involved in the development of solar cells for space applications since the 1960s. It quickly became apparent in this work that radiation damage caused to solar cells by electrons and protons trapped by the earth's magnetic field would seriously degrade the power output of photovoltaic arrays in extended missions. Techniques were therefore developed to harden the cells by shielding them with coverglass, etc. Ultimately, however, there is a limit to such approaches, which is determined by the radiation response of the semiconductor material employed. A desire for high efficiency and radiation resistance led to the development of alternative cell technologies such as GaAs, which has since become the technology of choice for many applications. InP cells are currently the most radiation resistant, high efficiency, planar cells known. NRL first sponsored InP solar cell technology in 1986, when Arizona State University was contracted to grow p/n cells by liquid phase epitaxy. NRL's interest in InP cells was generated by the results presented by Yamaguchi and his co-workers in the early 1980s on the remarkable radiation resistance of cells grown by diffusion of S into Zn doped p-type InP substrates. These cells also had beginning of life (BOL) efficiencies approximately 16%(AM0). Related to the radiation resistance of the cells was the fact that radiation-induced damage could be optically annealed by sunlight. Relatively large quantities of 1 x 2 cm(exp 2) diffused junction cells were made and were used on the MUSES-A and the EXOS-D satellites. These cells were also available in the U.S. through NIMCO, and were studied at NRL and elsewhere. Workers at NASA Lewis became involved in research in InP cells about the same time as NRL.

Summers, Geoffrey P.

1996-01-01

47

Assessing potential risk to alligators, Alligator mississippiensis, from nutria control with zinc phosphide rodenticide baits.  

PubMed

Nutria, Myocastor coypus, populations must be reduced when they cause substantial wetland damage. Control can include the rodenticide zinc phosphide, but the potential impacts to American alligators, Alligator mississippiensis, must be assessed. The mean amount of zinc phosphide per nutria found in nutria carcasses was 50 mg. Risk assessment determined that a conservative estimate for maximum exposure would be 173 mg zinc phosphide for a 28 kg alligator, or 6.2 mg/kg. Probit analysis found an LD(50) for alligators of 28 mg/kg. Our studies suggest that the use of zinc phosphide to manage nutria populations would pose only a small risk to alligators. PMID:20431861

Witmer, Gary W; Eisemann, John D; Primus, Thomas M; O'Hare, Jeanette R; Perry, Kelly R; Elsey, Ruth M; Trosclair, Phillip L

2010-06-01

48

Key factors limiting the open circuit voltage of n(+)pp(+) indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

Solar cells made from gallium arsenide (Gaas), with a room temperature bandgap of E(sub g) = 1.43 eV have exhibited the best measured open circuit voltage (V sub oc) of 1.05 V at 1 AM0, 25 C. The material InP is in many ways similar to GaAs. A simple calculation comparing InP to GaAs then shows that solar cells made from InP, with E(sub g) = 1.35 at 300 K, should exhibit the best measured V sub oc of approximately 950 mV at 1 AM0, 300 K. However, to date, the best measured V sub oc for InP solar cells made by any fabrication method is 899 mV at AM1.5, 25 C which would translate to 912 mV at 1 AM0, 25 C. The V sub oc of an n(+)pp(+) InP solar cell is governed by several factors. Of these, some factors, such as the thickness and doping of the emitter and base regions, are easily controlled and can be adjusted to desired values dictated by a good performance optimizing model. Such factors were not considered. There are other factors which also govern V sub oc, and their values are not so easily controlled. The primary ones among these are (1) the indirect or Hall-Shockley-Read lifetimes in the various regions of the cell, (2) the low-doping intrinsic carrier concentration n(sub i) of the InP material, (3) the heavy doping factors in the emitter and BSF regions, and (4) the front surface recombination velocity S(sub F). The influence of these latter factors on the V sub oc of the n(+)pp(+) InP solar cell and the results were used to produce a near-optimum design of the n(+)pp(+) InP solar cell.

Goradia, Chandra; Thesling, William; Weinberg, Irving

1990-01-01

49

Key factors limiting the open circuit voltage of n(+)pp(+) indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

Solar cells made from gallium arsenide (GaAs), with a room temperature bandgap of E(sub g) = 1.43 eV have exhibited the best measured open circuit voltage (V sub OC) of 1.05 V at 1 AMO, 25 C. The material InP is in many ways similar to GaAs. A simple calculation comparing InP to GaAs then shows that solar cells made from InP, with E(sub g) = 1.35 at 300 K, should exhibit the best measured (V sub OC) of approximately 950 mV at 1 AMO, 300 K. However, to date, the best measured V(sub OC) for InP solar cells made by any fabrication method is 899 mV at AM1.5, 25 C which would translate to 912 mV at 1 AMO, 25 C. The V(sub OC) of an n(+)pp(+) InP solar cell is governed by several factors. Of these, some factors, such as the thickness and doping of the emitter and base regions, are easily controlled and can be adjusted to desired values dictated by a good performance optimizing model. Such factors were not considered. There are other factors which also govern V(sub OC), and their values are not so easily controlled. The primary ones among these are (1) the indirect or Hall-Shockley-Read lifetimes in the various regions of the cell, (2) the low-doping intrinsic carrier concentration n(sub i) of the InP material, (3) the heavy doping factors in the emitter and BSF regions, and (4) the front surface recombination velocity S(sub F). The influence of these latter factors on the V(sub OC) of the n(+)pp(+) InP solar cell and the results were used to produce a near-optimum design of the n(+)pp(+) InP solar cell.

Goradia, Chandra; Thesling, William; Weinberg, Irving

1991-01-01

50

Indium tin oxide and indium phosphide heterojunction nanowire array solar cells  

SciTech Connect

Heterojunction solar cells were formed with a position-controlled InP nanowire array sputtered with indium tin oxide (ITO). The ITO not only acted as a transparent electrode but also as forming a photovoltaic junction. The devices exhibited an open-circuit voltage of 0.436?V, short-circuit current of 24.8?mA/cm{sup 2}, and fill factor of 0.682, giving a power conversion efficiency of 7.37% under AM1.5?G illumination. The internal quantum efficiency of the device was higher than that of the world-record InP cell in the short wavelength range.

Yoshimura, Masatoshi, E-mail: yoshimura@rciqe.hokudai.ac.jp; Nakai, Eiji; Fukui, Takashi [Graduate School of Information Science and Technology, and Research Center for Integrated Quantum Electronics (RCIQE), Hokkaido University, Kita 13 Nishi 8, Sapporo 0608628 (Japan)] [Graduate School of Information Science and Technology, and Research Center for Integrated Quantum Electronics (RCIQE), Hokkaido University, Kita 13 Nishi 8, Sapporo 0608628 (Japan); Tomioka, Katsuhiro [Graduate School of Information Science and Technology, and Research Center for Integrated Quantum Electronics (RCIQE), Hokkaido University, Kita 13 Nishi 8, Sapporo 0608628 (Japan) [Graduate School of Information Science and Technology, and Research Center for Integrated Quantum Electronics (RCIQE), Hokkaido University, Kita 13 Nishi 8, Sapporo 0608628 (Japan); PRESTO, Japan Science and Technology Agency (JST), Honcho Kawaguchi, 3320012 Saitama (Japan)

2013-12-09

51

Naval Research Laboratory`s programs in advanced indium phosphide solar cell development  

SciTech Connect

The Naval Research Laboratory has been involved in developing InP solar cell technology since 1988. The purpose of these programs was to produce advanced cells for use in very high radiation environments, either as a result of operating satellites in the Van Allen belts or for very long duration missions in other orbits. Richard Statler was technical representative on the first program, with Spire Corporation as the contractor, which eventually produced several hundred, high efficiency 2 x 2 sq cm single crystal InP cells. The shallow homojunction technology which was developed in this program enabled cells to be made with AMO, one sun efficiencies greater than 19%. Many of these cells have been flown on space experiments, including PASP Plus, which have confirmed the high radiation resistance of InP cells. NRL has also published widely on the radiation response of these cells and also on radiation-induced defect levels detected by DLTS, especially the work of Rob Walters and Scott Messenger. In 1990 NRL began another Navy-sponsored program with Tim Coutts and Mark Wanlass at the National Renewable Energy Laboratory (NREL), to develop a one sun, two terminal space version of the InP-InGaAs tandem junction cell being investigated at NREL for terrestrial applications. These cells were grown on InP substrates. Several cells with AMO, one sun efficiencies greater than 22% were produced. Two 2 x 2 sq cm cells were incorporated on the STRV lA/B solar cell experiment. These were the only two junction, tandem cells on the STRV experiment. The high cost and relative brittleness of InP wafers meant that if InP cell technology were to become a viable space power source, the superior radiation resistance of InP would have to be combined with a cheaper and more robust substrate. The main technical challenge was to overcome the effect of the dislocations produced by the lattice mismatch at the interface of the two materials.

Summers, G.P.

1995-10-01

52

Comparison of arsenide and phosphide based graded buffer layers used in inverted metamorphic solar cells  

NASA Astrophysics Data System (ADS)

The effect of graded buffer layer (GBL) composition on inverted metamorphic 1.1-eV In0.24Ga0.76As single-junction solar cells, with applications as a subcell in high-efficiency multijunction solar cells, is investigated. In experiment A, AlxInyGa(1-x-y)As was used as a GBL to transition from the GaAs substrate lattice constant to that of the In0.24Ga0.76As cell. In experiment B, In1-xGaxP was employed. Both GBLs were deposited using growth conditions optimized for lattice-matched growth. Reciprocal space maps showed that the InGaAs cell was fully relaxed in both experiments. They also revealed that the AlInGaAs GBL relaxed very quickly after the start of growth (<0.1 ?m). The InGaP GBL on the other hand remained partially strained throughout its structure and full relaxation was only achieved after growth of the InGaAs cell. Atomic force microscopy of the surface of the AlInGaAs GBL showed typical cross-hatch morphology with a roughness of 8.9 nm. The surface of the InGaP GBL was much rougher at 18.3 nm with unusual morphology, likely due to 3D island formation due to unrelieved strain. These findings were confirmed by transmission electron microscopy where the InGaAs cell of experiment A was largely free of imperfections with a defect density of 1.1 106 cm-2. Experiment B had defects readily seen throughout the GBL and the InGaAs cell above had a defect density of 1.5 109 cm-2. The hardness of the AlInGaAs GBL surface was measured to be 7.2 GPa and exhibited an indentation size effect. The hardness of the InGaP GBL surface was 10.2 GPa regardless of the depth of penetration of the indenter. The lack of indentation size effect in InGaP is due to the high density of dislocations already present in the material due to unrelieved strain. Solar cells fabricated from experiment A wafers exhibited excellent band gap-voltage offset Woc = (Eg/q) - Voc of 0.414 V. Cells from experiment B exhibited a poor Woc of 0.686 V, most likely due to the threading dislocations acting as non-radiative recombination centers.

Zakaria, A.; King, Richard R.; Jackson, M.; Goorsky, M. S.

2012-07-01

53

Indium phosphide solar cells - P(+)-N or N(+)-P?  

NASA Astrophysics Data System (ADS)

A modeling study is carried out to determine whether p(+)-n or n(+)-p InP solar cells give better performance. The physical model used was standard except that radiative recombination was modified to allow for photon recycling. The numerical model combined 1D solutions of the transport equations with the Handy model for series resistance. The parameters optimized were: front SRV, emitter doping, emitter thickness, number, and width of grid fingers. Calculations were done with only radiative recombination in the bulk and with a state-of-the-art level of Schottky-Read-Hall (SRH) recombination. The results suggest that in the absence of SRH recombination p(+)-n with eta = 23.4 percent are better than n(+)-p with eta = 23.1 percent.

Parrott, J. E.; Potts, A.

54

A theoretical comparison of the near-optimum design and predicted performance of n/p and p/n indium phosphide homojunction solar cells  

NASA Technical Reports Server (NTRS)

Using a detailed simulation model of p(+)nn(+) and n(+)pp(+) indium phosphide (InP) homojunction solar cells, extensive parametric variation computer simulation runs were performed to aid in making near-optimum designs for these two solar cell configurations. The values of all the geometrical and material parameters corresponding to the near-optimal designs of both these configurations are presented. The results of parametric variation runs are presented for each configuration showing how the performance parameters J(sub sc), V(sub oc), and eta vary with each of the cell design parameters for the near-optimally designed cell. Finally, the theoretically obtained results are discussed, and the relative merits and drawbacks of the two configurations are compared.

Goradia, Chandra; Thesling, William; Weinberg, Irving

1991-01-01

55

Indium phosphide/cadmium sulfide thin-film solar cells. Semiannual report, July 1980-December 1980  

SciTech Connect

InP thin films were deposited by planar reactive deposition on recyrstallized CdS (RXCdS) and semi-insulating (100) InP substrates and evaluated as potential layers for an all-thin-film solar cell. Films prepared on RXCdS at approximately 330/sup 0/C contained a mixture of grains having both large and submicron lateral dimensions. SIMS analysis showed the interdiffusion profiles to be well behaved and, within the resolution of the analysis, no significant difference in the profiles between structures prepared at 330/sup 0/C and 380/sup 0/C. Be-doped epitaxial films, deposited on semi-insulating InP at 330/sup 0/C, showed both n- and p-type behavior. Films prepared at higher and lower temperatures with a freshly Be-charged In source were p-type and n-type, respectively; the n-type behavior is associated with an excess of n-type native defects. SIMS analyses confirmed the presence of Be in all Be-doped films. Growth with deviation from stoichiometry was initiated at 330/sup 0/C to reduce the concentration of native defects. Growth of Be-doped films at higher substrate temperature with the same Be-doped source after several runs eventually resulted in n-type films. Analyses of the In source and films were initiated to determine the cause of the transient doping. As an alternative to Be doping, p-type Zn-doped InP films were prepared on InP semi-insulating substrates with room-temperature carrier concentration and mobilities of 6 x 10/sup 16/ cm/sup -3/, and 80 cm/sup 2//Vsec, respectively.

Zanio, K.

1981-03-01

56

Electrochemical deposition of zinc oxide nanorods for hybrid solar cells  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanorod arrays for inorganic/organic hybrid solar cells were electrochemically deposited on indium tin oxide (ITO) substrates with a rotating disk electrode setup. The addition of a ZnO seed layer on the ITO prior to electrochemical deposition improved the morphology of the nanorods, resulting in nanorods with smaller and homogenous diameters as well as a higher degree of vertical orientation on to the substrate. The ZnO films deposited on the seeded ITO substrates had higher optical transmittance and lower concentration of defects. Chronoamperometric transient curves show that nucleation and coalescence occurred later for bare ITO substrates, indicating lower densities of initial nuclei, resulting in the growth of nanorods with larger diameters. The solar cell characteristics of the devices fabricated from the seeded ITO substrates were better. The seed layer also acts as a hole-blocking layer, preventing the direct contact between the hole-transporting polymer material and the ITO.

Torres Damasco Ty, Jennifer; Yanagi, Hisao

2015-04-01

57

Power recovery of radiation damaged MOCVD grown indium phosphide on silicon solar cells through argon-ion laser annealing. Master`s thesis  

SciTech Connect

This thesis reports the results of a laser annealing technique used to remove defect sites from radiation damaged indium phosphide on silicon MOCVD grown solar cells. This involves the illumination of damaged solar cells with a continuous wave laser to produce a large forward-biased current. The InP/Si cells were irradiated with 1 MeV electrons to a given fluence, and tested for degradation. Light from an argon laser was used to illuminate four cells with an irradiance of 2.5 W/sq cm, producing a current density 3 to 5 times larger than AMO conditions. Cells were annealed at 19 deg C with the laser and at 25 deg C under AMO conditions. Annealing under laser illumination of n/p-type cells resulted in recovery of 48%. P/n type cells lost 4 to 12% of the assumed degradaton. Annealing under AMO conditions resulted in power recovery of 70% in n/p type cells. P/n-type cells recovered approximately 16% of lost power. Results indicate that significant power recovery results from the annealing of defects within n/p type InP/Si solar cells.

Boyer, L.L.

1996-06-01

58

Effects of Gallium-Phosphide and Indium-Gallium-Antimonide semiconductor materials on photon absorption of multijunction solar cells  

Microsoft Academic Search

The main challenge in the photovoltaic industry is making the solar cells more cost effective. Single junction solar cells can only absorb a certain wavelength of the solar spectrum, hence produce less efficiency. In contrary multijunction solar cells direct sunlight towards matched spectral sensitivity by splitting the spectrum into smaller slices. The high efficiency multijunction photovoltaics made up of III-V

Indranil Bhattacharya; Simon Y. Foo

2010-01-01

59

Thin film cadmium telluride, zinc telluride, and mercury zinc telluride solar cells  

SciTech Connect

This report describes research to demonstrate (1) thin film cadmium telluride solar cells with a quantum efficiency of 75% or higher at 0. 44 {mu}m and a photovoltaic efficiency of 11.5% or greater, and (2) thin film zinc telluride and mercury zinc telluride solar cells with a transparency to sub-band-gap radiation of 65% and a photovoltaic conversion efficiency of 5% and 8%, respectively. Work was directed at (1) depositing transparent conducting semiconductor films by solution growth and metal-organic chemical vapor deposition (MOCVD) technique, (2) depositing CdTe films by close-spaced sublimation (CSS) and MOCVD techniques, (3) preparing and evaluating thin film CdTe solar cells, and (4) preparing and characterizing thin film ZnTe, CD{sub 1-x}Zn{sub 1-x}Te, and Hg{sub 1-x}Zn{sub x}Te solar cells. The deposition of CdS films from aqueous solutions was investigated in detail, and their crystallographic, optical, and electrical properties were characterized. CdTe films were deposited from DMCd and DIPTe at 400{degrees}C using TEGa and AsH{sub 3} as dopants. CdTe films deposited by CSS had significantly better microstructures than those deposited by MOCVD. Deep energy states in CdTe films deposited by CSS and MOCVD were investigated. Thin films of ZnTe, Cd{sub 1- x}Zn{sub x}Te, and Hg{sub 1-x}Zn{sub x}Te were deposited by MOCVD, and their crystallographic, optical, and electrical properties were characterized. 67 refs.

Chu, T.L. (University of South Florida, Tampa, FL (United States))

1992-04-01

60

Predicted performance of near-optimally designed indium phosphide space solar cells at high intensities and temperatures  

NASA Technical Reports Server (NTRS)

The authors calculated the expected performance dependence of near-optimally designed shallow homojunction n+pp+ InP solar cells on incident intensities up to 200 AM0 and temperatures up to 100 deg C (373 K). Both circular and rectangular cells were considered, the former for use in a Cassegrainian concentrator array at 100 AM0, 80-100 deg C and the latter for use in a Slats concentrator array at 20 AM0, 80-100 deg C. With efficiencies near 22 percent at 80 deg C, both the circular and rectangular InP shallow homojunction solar cells compare very favorably to GaAs cells of the same design and may be preferable to the GaAs cells for space applications because of the superior radiation tolerance of the InP cells.

Goradia, Chandra; Thesling, William; Goradia, Manju Ghalla; Weinberg, Irving; Swartz, Clifford K.

1988-01-01

61

Diagnosis of zinc phosphide poisoning in chickens using a new analytical approach.  

PubMed

Approximately 200 chickens were found dead after the flooring of a slat-and-litter house was breached. No clinical signs of illness were observed in the surviving birds. During necropsy, rolled oats were found in the chickens' crops and gizzards, and the contents had a petroleum-like odor. Histopathologic examination revealed severe pulmonary edema and congestion of the chickens' lungs, hearts, livers, and kidneys. Based on the history and necropsy findings, zinc phosphide exposure was suspected. Diagnosis of zinc phosphide poisoning has previously been based on history of exposure, identification of the bait material in the gastrointestinal tract, and chemical detection of phosphine gas. However, currently available diagnostic methods are nonconfirmatory, and may produce false positive results. The objective of this case report was to determine whether the sudden death described in these chickens was caused by the ingestion of zinc phosphide, by developing a sensitive and highly specific gas chromatography/mass spectrometry (GC/MS) methodology for analysis of the gastrointestinal samples submitted to the laboratory. It was also found that the determination of zinc concentrations in liver or kidney tissue or stomach contents is not a reliable indicator of zinc phosphide poisoning. PMID:16094837

Tiwary, Asheesh K; Puschner, Birgit; Charlton, Bruce R; Filigenzi, Michael S

2005-06-01

62

Low-Resistivity Zinc Selenide for Heterojunctions  

NASA Technical Reports Server (NTRS)

Magnetron reactive sputtering enables doping of this semiconductor. Proposed method of reactive sputtering combined with doping shows potential for yielding low-resistivity zinc selenide films. Zinc selenide attractive material for forming heterojunctions with other semiconductor compounds as zinc phosphide, cadmium telluride, and gallium arsenide. Semiconductor junctions promising for future optoelectronic devices, including solar cells and electroluminescent displays. Resistivities of zinc selenide layers deposited by evaporation or chemical vapor deposition too high to form practical heterojunctions.

Stirn, R. J.

1986-01-01

63

CdS\\/CdTe Thin-Film Solar Cell with a Zinc Stannate Buffer Layer  

Microsoft Academic Search

This paper describes an improved CdS\\/CdTe polycrystalline thin-film solar-cell device structure that integrates a zinc stannate (Zn2SnO4 or ZTO) buffer layer between the transparent conductive oxide (TCO) layer and the CdS window layer. Zinc stannate films have a high bandgap, high transmittance, low absorptance, and low surface roughness. In addition, these films are chemically stable and exhibit higher resistivities that

X. Wu; P. Sheldon; Y. Mahathongdy; R. Ribelin; A. Mason; H. R. Moutinho; T. J. Coutts

1998-01-01

64

CdS\\/CdTe thin-film solar cell with a zinc stannate buffer layer  

Microsoft Academic Search

This paper describes an improved CdS\\/CdTe polycrystalline thin-film solar-cell device structure that integrates a zinc stannate (Zn2SnO4 or ZTO) buffer layer between the transparent conductive oxide (TCO) layer and the CdS window layer. Zinc stannate films have a high bandgap, high transmittance, low absorptance, and low surface roughness. In addition, these films are chemically stable and exhibit higher resistivities that

X. Wu; P. Sheldon; Y. Mahathongdy; R. Ribelin; A. Mason; H. R. Moutinho; T. J. Coutts

1999-01-01

65

Synthesis of zinc chlorophyll materials for dye-sensitized solar cell applications  

NASA Astrophysics Data System (ADS)

To design sensitizers for dye sensitized solar cells (DSSCs), a series of zinc chlorins with different substituents were synthesized. Novel zinc methyl 3-devinyl-3-hydroxymethyl-20-phenylacetylenylpyropheophorbide-a (ZnChl-1), zinc methyl 20-bromo-3-devinyl-3-hydroxymethylpyropheophorbide-a (ZnChl-2), zinc methyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-3), zinc propyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-4) were synthesized and their photovoltaic performances were evaluated in dye-sensitized solar cells. Photoelectrodes with a 7 ?m thick nanoporous layer and a 5 ?m thick light-scattering layer were used to fabricate dye sensitized solar cells. The best efficiency was obtained with ZnChl-2 sensitizer. ZnChl-2 gave a Jsc of 3.5 mA/cm2, Voc of 412 mV, FF of 0.56 and an overall conversion efficiency of 0.81 at full sun (1000 W m-2).

Erten-Ela, Sule; Vakuliuk, Olena; Tarnowska, Anna; Ocakoglu, Kasim; Gryko, Daniel T.

2015-01-01

66

Synthesis of zinc chlorophyll materials for dye-sensitized solar cell applications.  

PubMed

To design sensitizers for dye sensitized solar cells (DSSCs), a series of zinc chlorins with different substituents were synthesized. Novel zinc methyl 3-devinyl-3-hydroxymethyl-20-phenylacetylenylpyropheophorbide-a (ZnChl-1), zinc methyl 20-bromo-3-devinyl-3-hydroxymethylpyropheophorbide-a (ZnChl-2), zinc methyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-3), zinc propyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-4) were synthesized and their photovoltaic performances were evaluated in dye-sensitized solar cells. Photoelectrodes with a 7 ?m thick nanoporous layer and a 5 ?m thick light-scattering layer were used to fabricate dye sensitized solar cells. The best efficiency was obtained with ZnChl-2 sensitizer. ZnChl-2 gave a Jsc of 3.5 mA/cm(2), Voc of 412 mV, FF of 0.56 and an overall conversion efficiency of 0.81 at full sun (1000 W m(-2)). PMID:25128681

Erten-Ela, Sule; Vakuliuk, Olena; Tarnowska, Anna; Ocakoglu, Kasim; Gryko, Daniel T

2015-01-25

67

A very low resistance, non-sintered contact system for use on indium phosphide concentrator/shallow junction solar cells  

NASA Technical Reports Server (NTRS)

An investigation is made into the possibility of providing low resistance contacts to shallow junction InP solar cells which do not require sintering and which do not cause device degradation even when subjected to extended annealing at elevated temperatures. We show that the addition of In to Au contacts in amounts that exceed the solid solubility limit lowers the as-fabricated (unsintered) contact resistivity (R sub c) to the 10(exp -5) ohm cm(exp 2) range. We next consider the contact system Au/Au2P3 which has been shown to exhibit as-fabricated R sub c values in the 10(exp -6) ohm cm(exp 2) range, but which fails quickly when heated. We show that the substitution of a refractory metal (W, Ta) for Au preserves the low R sub c values while preventing the destructive reactions that would normally take place in this system at high temperatures. We show, finally, that R sub c values in the 10(exp -7) ohm cm(exp 2) range can be achieved without sintering by combining the effects of In or Ga additions to Au contacts with the effects of introducing a thin Au2P3 layer at the metal-InP interface.

Weizer, Victor G.; Fatemi, Navid S.

1991-01-01

68

A very low resistance, non-sintered contact system for use on indium phosphide concentrator/shallow junction solar cells  

NASA Technical Reports Server (NTRS)

An investigation is made into the possibility of providing low resistance contacts to shallow junction InP solar cells which do not require sintering and which do not cause device degradation even when subjected to extended annealing at elevated temperatures. We show that the addition of In to Au contacts in amounts that exceed the solid solubility limit lowers the as-fabricated (unsintered) contact resistivity (R sub c) to the 10(exp -5) ohm cm(exp 2) range. We next consider the contact system Au/Au2P3, which has been shown to exhibit as-fabricated R sub c values in the 10(exp -6) ohm cm(exp 2) range, but which fails quickly when heated. We show that the substitution of a refractory metal (W, Ta) for Au preserves the low R sub c values while preventing the destructive reactions that would normally take place in this system at high temperatures. We show, finally, that R sub c values in the 10(exp -7) ohm cm(exp 2) range can be achieved without sintering by combining the effects of In or Ga additions to Au contacts with the effects of introducing a thin Au2P3 layer at the metal-InP interface.

Weizer, Victor G.; Fatemi, Navid S.

1991-01-01

69

Atomic Layer Deposition of zinc oxide for solar cell applications  

NASA Astrophysics Data System (ADS)

Atomic Layer Deposition (ALD) is a vapor phase thin film deposition technique, performed at low substrate temperatures, which enables the deposition of extremely uniform thin films. This technique is scalable up to very large substrates, making it very interesting for industrial applications. On the other hand, ZnO, both undoped and aluminum doped is commonly used as a transparent electrode in solar cells based on Cu(In,Ga)Se2 (CIGS), and is usually deposited by Physical Vapor Deposition techniques. In this paper, we investigate the potential of ALD for the deposition of ZnO windows for solar cell applications. Thin films of a few hundreds of nanometers were grown by ALD, both undoped and doped with aluminum. They were studied by X-ray diffraction, electrical transport measurements, Atomic Force Microscopy and transmittance experiments.

Moret, M.; Abou Chaaya, A.; Bechelany, M.; Miele, P.; Robin, Y.; Briot, O.

2014-11-01

70

Efficient inverted polymer solar cells based on conjugated polyelectrolyte and zinc oxide modified ITO electrode  

NASA Astrophysics Data System (ADS)

Efficient inverted polymer solar cells (PSCs) were constructed by utilizing a conjugated polyelectrolyte PFEOSO3Na and zinc oxide to modify the indium tin oxide (ITO) electrode. The ITO electrode modified by PFEOSO3Na and zinc oxide possesses high transparency, increased electron mobility, smoothened surface, and lower work function. PTB7:PC71BM inverted PSCs containing the modified ITO electrode achieved a high power conversion efficiency (PCE) of 8.49%, exceeding that of the control device containing a ZnO modified ITO electrode (7.48%). Especially, PCE-10:PC71BM inverted polymer solar cells achieved a high PCE up to 9.4%. These results demonstrate a useful approach to improve the performance of inverted polymer solar cells.

Yuan, Tao; Zhu, Xiaoguang; Zhou, Lingyu; Zhang, Jian; Tu, Guoli

2015-02-01

71

Conjugated phosphonic acid modified zinc oxide electron transport layers for improved performance in organic solar cells.  

PubMed

Phosphonic acid modification of zinc oxide (ZnO) electron transport layers in inverted P3HT:ICBA solar cells was studied to determine the effect of conjugated linkages between the aromatic and phosphonic acid attachment groups. For example, zinc oxide treated with 2,6-difluorophenylvinylphosphonic acid, having a conjugated vinyl group connecting the aromatic moiety to the phosphonic acid group, showed a 0.78 eV decrease in the effective work function versus unmodified ZnO, whereas nonconjugated 2,6-difluorophenylethylphosphonic acid resulted in a 0.57 eV decrease, as measured by Kelvin probe. This resulted in an average power conversion efficiency of 5.89% for conjugated 2,6-difluorophenyvinylphosphonic acid modified solar cells, an improvement over unmodified (5.24%) and nonconjugated phosphonic acid modified devices (5.64%), indicating the importance of the conjugated linkage. PMID:25329245

Braid, Jennifer L; Koldemir, Unsal; Sellinger, Alan; Collins, Reuben T; Furtak, Thomas E; Olson, Dana C

2014-11-12

72

Indium phosphide/cadmium sulfide thin-film solar cells. Final report, May 1979 through July 1980  

SciTech Connect

Thin-film InP/RXCdS/ITO/GLASS devices were prepared by depositing ITO on low-cost glass substrate, depositing CdS on the ITO by thermal evaporation, increasing the CdS lateral grain size by recrystallization, and depositing p-type InP by planar reactive deposition (PRD) on the recrystallized CdS (RXCdS). Yields of the RXCdS/ITO/GLASS substrates were increased to 90% with lateral dimensions of the RXCdS grains as large as 0.3 mm. P-type InP layers were obtained with Be doping. S-doping via vapor transport from the CdS was eliminated by capping the entire RXCdS substrate with InP. For InP deposited on RXCdS at 380/sup 0/C, devices showed blocking action with a barrier height of about 0.5 V but no light response, possibly due to an intermediate approx. 3-..mu..m-thick n-InP layer from diffusion of S from the RXCdS. These results were achieved despite poor InP epitaxy due to an approx. 0.5-..mu..m-thick In-Cd-S transition layer between the InP and the RXCdS. InP films were subsequently deposited on RXCdS at the reduced substrate temperature of 280/sup 0/C to reduce S-diffusion and improve the quality of the epitaxy. Complete InP epitaxy on RXCdS was achieved with the lateral dimensions of the InP (approx. = 40 ..mu..m) replicating that of the RXCdS. Given the increase in the concentration of n-type native defects as substrate temperature is decreased, the present lower limit for obtaining p-type InP by vacuum technologies appears to be about 300/sup 0/C. A 300 to 350/sup 0/C range of substrate temperature appears to befeasible for preparing large-grained p-type InP for both frontwall and backwall cell. However, if the thickness of the n-type layer due to S diffusion cannot be kept to less than a few thousand Angstroms, then development must be restricted to the frontwall cells.

Zanio, K.

1980-09-01

73

Efficacy of zinc phosphide baits to control voles in alfalfa an enclosure study  

Microsoft Academic Search

The efficacy of broadcasting zinc phosphide (Zn3P2) grain baits as an acute rodenticide to control graytailed voles (Microtus canicaudus) in alfalfa (Medicago sativa) was assessed. A total of 428 voles was distributed within 18, 0.2-ha enclosures having a 2+ year stand of plants. Single, pre-bait (0.0% Zn3P2) and test-\\/control-(2.00.0% Zn3P2) bait broadcasts (11.2 kg ha?1) were applied within enclosures 18

R. T. Sterner; C. A. Ramey; W. D. Edge; T. Manning; J. O. Wolff; K. A. Fagerstonez

1996-01-01

74

The complex interface chemistry of thin-film silicon/zinc oxide solar cell structures.  

PubMed

The interface between solid-phase crystallized phosphorous-doped polycrystalline silicon (poly-Si(n(+))) and aluminum-doped zinc oxide (ZnO:Al) was investigated using spatially resolved photoelectron emission microscopy. We find the accumulation of aluminum in the proximity of the interface. Based on a detailed photoemission line analysis, we also suggest the formation of an interface species. Silicon suboxide and/or dehydrated hemimorphite have been identified as likely candidates. For each scenario a detailed chemical reaction pathway is suggested. The chemical instability of the poly-Si(n(+))/ZnO:Al interface is explained by the fact that SiO2 is more stable than ZnO and/or that H2 is released from the initially deposited a-Si:H during the crystallization process. As a result, Zn (a deep acceptor in silicon) is "liberated" close to the silicon/zinc oxide interface presenting the inherent risk of forming deep defects in the silicon absorber. These could act as recombination centers and thus limit the performance of silicon/zinc oxide based solar cells. Based on this insight some recommendations with respect to solar cell design, material selection, and process parameters are given for further knowledge-based thin-film silicon device optimization. PMID:25363298

Gerlach, D; Wimmer, M; Wilks, R G; Flix, R; Kronast, F; Ruske, F; Br, M

2014-12-21

75

CdS/CdTe thin-film solar cell with a zinc stannate buffer layer  

SciTech Connect

This paper describes an improved CdS/CdTe polycrystalline thin-film solar-cell device structure that integrates a zinc stannate (Zn{sub 2}SnO{sub 4} or ZTO) buffer layer between the transparent conductive oxide (TCO) layer and the CdS window layer. Zinc stannate films have a high bandgap, high transmittance, low absorptance, and low surface roughness. In addition, these films are chemically stable and exhibit higher resistivities that are roughly matched to that of the CdS window layer in the device structure. Preliminary device results have demonstrated that by integrating a ZTO buffer layer in both SnO{sub 2}-based and Cd{sub 2}SnO{sub 4} (CTO)-based CdS/CdTe devices, performance and reproducibility can be significantly enhanced. {copyright} {ital 1999 American Institute of Physics.}

Wu, X.; Sheldon, P.; Mahathongdy, Y.; Ribelin, R.; Mason, A.; Moutinho, H.R.; Coutts, T.J. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)

1999-03-01

76

CdS/CdTe Thin-Film Solar Cell with a Zinc Stannate Buffer Layer  

SciTech Connect

This paper describes an improved CdS/CdTe polycrystalline thin-film solar-cell device structure that integrates a zinc stannate (Zn2SnO4 or ZTO) buffer layer between the transparent conductive oxide (TCO) layer and the CdS window layer. Zinc stannate films have a high bandgap, high transmittance, low absorptance, and low surface roughness. In addition, these films are chemically stable and exhibit higher resistivities that are roughly matched to that of the CdS window layer in the device structure. Preliminary device results have demonstrated that by integrating a ZTO buffer layer in both SnO2-based and Cd2SnO4 (CTO)-based CdS/CdTe devices, performance and reproducibility can be significantly enhanced

Wu, X.; Sheldon, P.; Mahathongdy, Y.; Ribelin, R.; Mason, A.; Moutinho, H. R.; Coutts, T. J.

1998-10-28

77

CdS/CdTe thin-film solar cell with a zinc stannate buffer layer  

NASA Astrophysics Data System (ADS)

This paper describes an improved CdS/CdTe polycrystalline thin-film solar-cell device structure that integrates a zinc stannate (Zn2SnO4 or ZTO) buffer layer between the transparent conductive oxide (TCO) layer and the CdS window layer. Zinc stannate films have a high bandgap, high transmittance, low absorptance, and low surface roughness. In addition, these films are chemically stable and exhibit higher resistivities that are roughly matched to that of the CdS window layer in the device structure. Preliminary device results have demonstrated that by integrating a ZTO buffer layer in both SnO2-based and Cd2SnO4 (CTO)-based CdS/CdTe devices, performance and reproducibility can be significantly enhanced.

Wu, X.; Sheldon, P.; Mahathongdy, Y.; Ribelin, R.; Mason, A.; Moutinho, H. R.; Coutts, T. J.

1999-03-01

78

Novel planar binuclear zinc phthalocyanine sensitizer for dye-sensitized solar cells: Synthesis and spectral, electrochemical, and photovoltaic properties  

NASA Astrophysics Data System (ADS)

A planar binuclear zinc phthalocyanine was newly synthesized for use in dye-sensitized solar cells, based on Schiff base and asymmetric amino zinc phthalocyanine. The novel compounds were characterized using FTIR, UV-Vis, 1H NMR, cyclic voltammetry and elemental analysis. From the reduction and oxidation behavior, it is proved that APC and bi-NPC have negative LUMO levels and positive HOMO levels, satisfying the energy gap rule, and can be employed as sensitizers for dye-sensitized solar cells (DSSCs) applications.

Zhu, Baiqing; Zhang, Xuejun; Han, Mingliang; Deng, Pengfei; Li, Qiaoling

2015-01-01

79

Chemical bath deposited zinc sulfide buffer layers for copper indium gallium sulfur-selenide solar cells and device analysis  

Microsoft Academic Search

Cadmium-free copper indium gallium sulfur-selenide (CIGSS) thin film solar cells have been fabricated using chemical bath deposited (CBD) zinc sulfide (ZnS) buffer layers. Shell Solar Industries provided high quality CIGSS absorber layers. The use of CBD-ZnS, which is a higher band gap material than CdS, improved the quantum efficiency of fabricated cells at lower wavelengths, leading to an increase in

Sambhu N. Kundu; Larry C. Olsen

2005-01-01

80

Fabrication and characterization of P3HT:PCBM-based thin film organic solar cells with zinc phthalocyanine  

NASA Astrophysics Data System (ADS)

[6,6]-phenyl C61-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.

Maruhashi, Haruto; Oku, Takeo; Suzuki, Atsushi; Akiyama, Tsuyoshi; Yamasaki, Yasuhiro

2015-02-01

81

Enhanced omni-directional performance of copper zinc tin sulfide thin film solar cell by gradient index coating  

NASA Astrophysics Data System (ADS)

Many types of thin-film solar cells have a top, transparent conducting oxide (TCO) coating (such as aluminum-doped zinc oxide (AZO)) through which light is transmitted and current collected. In this paper, we demonstrate an effective antireflective coating for TCO surfaces using a gradient index coating formed from co-sputtered AZO and silicon dioxide (SiO2) targets that reduces reflection loss from the TCO. When applied to an active solar device, the power conversion efficiency of the solar cell increased by >10% when measured at normal incidence and >20% at angles 10 or greater.

Ge, Zhongyang; Rajbhandari, Pravakar; Hu, Junjie; Emrani, Amin; Dhakal, Tara P.; Westgate, Charles; Klotzkin, David

2014-03-01

82

Highly efficient copper-zinc-tin-selenide (CZTSe) solar cells by electrodeposition.  

PubMed

Highly efficient copper-zinc-tin-selenide (Cu2ZnSnSe4 ; CZTSe) thin-film solar cells are prepared via the electrodepostion technique. A metallic alloy precursor (CZT) film with a Cu-poor, Zn-rich composition is directly deposited from a single aqueous bath under a constant current, and the precursor film is converted to CZTSe by annealing under a Se atmosphere at temperatures ranging from 400 C to 600 C. The crystallization of CZTSe starts at 400 C and is completed at 500 C, while crystal growth continues at higher temperatures. Owing to compromises between enhanced crystallinity and poor physical properties, CZTSe thin films annealed at 550 C exhibit the best and most-stable device performances, reaching up to 8.0 % active efficiency; among the highest efficiencies for CZTSe thin-film solar cells prepared by electrodeposition. Further analysis of the electronic properties and a comparison with another state-of-the-art device prepared from a hydrazine-based solution, suggests that the conversion efficiency can be further improved by optimizing parameters such as film thickness, antireflection coating, MoSe2 formation, and p-n junction properties. PMID:24692285

Jeon, Jong-Ok; Lee, Kee Doo; Seul Oh, Lee; Seo, Se-Won; Lee, Doh-Kwon; Kim, Honggon; Jeong, Jeung-hyun; Ko, Min Jae; Kim, BongSoo; Son, Hae Jung; Kim, Jin Young

2014-04-01

83

Alkyl Surface Treatments of Planar Zinc Oxide in Hybrid Organic/Inorganic Solar Cells  

SciTech Connect

Hybrid organic/inorganic solar cells have not lived up to their potential because of poor interface properties. Interfacial molecular layers provide a way of adjusting these devices to improve their performance. We have studied a prototypical system involving poly(3-hexylthiophene) (P3HT) on planar zinc oxide (ZnO) films that have been modified with two types of molecules having identical 18-carbon alkyl chain termination and different surface attachments: octadecanethiol (ODT) and octadecyltriethoxysilane (OTES). We examined the functionalized surfaces using water contact angle measurements, Kelvin probe measurements, infrared absorbance spectroscopy, and atomic force microscopy. These have shown that OTES forms disordered incomplete monolayers, while ODT is prone to develop multilayered islands. Both treatments enhance polymer ordering. However, inverted solar cell devices fabricated with these treated interfaces performed very differently. ODT improves the short circuit current (J{sub SC}), open circuit voltage (V{sub OC}), and power conversion efficiency ({eta}), while these parameters all decrease in devices constructed from OTES-treated ZnO. The differences in V{sub OC} are related to modifications of the surface dipole associated with deposition of the two types of alkyl molecules, while changes in J{sub SC} are attributed to a balance between charge transfer blocking caused by the saturated hydrocarbon and the improved hole mobility in the polymer.

Allen, C. G.; Baker, D. J.; Brenner, T. M.; Weigand, C. C.; Albin, J. M.; Steirer, K. X.; Olson, D. C.; Ladam, C.; Ginley, D. S.; Collins, R. T.; Furtak, T. E.

2012-04-26

84

Semitransparent polymer-based solar cells with aluminum-doped zinc oxide electrodes.  

PubMed

With the use of two transparent electrodes, organic polymer-fullerene solar cells are semitransparent and may be combined to parallel-connected multijunction devices or used for innovative applications like power-generating windows. A challenging issue is the optimization of the electrodes, to combine high transparency with adequate electric properties. In the present work, we study the potential of sputter-deposited aluminum-doped zinc oxide as an alternative to the widely used but relatively expensive indium tin oxide (ITO) as cathode material in semitransparent polymer-fullerene solar cells. Concerning the anode, we utilized an insulator-metal-insulator structure based on ultrathin Au films embedded between two evaporated MoO3 layers, with the outer MoO3 film (capping layer) serving as a light coupling layer. The performance of the ITO-free semitransparent polymer-fullerene solar cells was systematically studied as dependent on the thickness of the capping layer and the active layer as well as the illumination direction. These variations were found to have strong impact on the obtained photocurrent densities. We performed optical simulations of the electric field distribution within the devices using the transfer-matrix method, to analyze the origin of the current density variations in detail and provide deep insight into the device physics. With the conventional absorber materials studied here, optimized ITO-free and semitransparent devices reached 2.0% power conversion efficiency and a maximum optical transmission of 60%, with the device concept being potentially transferable to other absorber materials. PMID:25495167

Wilken, Sebastian; Wilkens, Verena; Scheunemann, Dorothea; Nowak, Regina-Elisabeth; von Maydell, Karsten; Parisi, Jrgen; Borchert, Holger

2015-01-14

85

Design of a three-layer antireflection coating for high efficiency indium phosphide solar cells using a chemical oxide as first layer  

NASA Technical Reports Server (NTRS)

It is well known that the behavior of III-V compound based solar cells is largely controlled by their surface, since the majority of light generated carriers (63% for GaAs and 79% for InP) are created within 0.2 mu m of the surface of the illuminated cell. Consequently, the always observed high surface recombination velocity (SRV) on these cells is a serious limiting factor for their high efficiency performance, especially for those with p-n junction made by either thermal diffusion or ion implantation. A good surface passivation layer, ideally a grown oxide as opposed to a deposited one, will cause a significant reduction in the SRV without adding interface problems, thus improving the performance of III-V compound based solar cells. Another significant benefit to the overall performance of the solar cells can be achieved by a substantial reduction of their large surface optical reflection by the use of a well designed antireflection (AR) coating. In this paper, we demonstrate the effectiveness of using a chemically grown thermally and chemically stable oxide, not only for surface passivation but also as an integral part of a 3-layer AR coating for thermally diffused p+n InP solar cells. A phosphorus-rich interfacial oxide, In(PO3)3, is grown at the surface of the p+ emitter using an etchant based on HNO3, o-H3PO4 and H2O2. This oxide has the unique properties of passivating the surface as well as serving as an efficient antireflective layer yielding a measured record high AMO open-circuit voltage of 890.3 mV on a thermally diffused InP(Cd,S) solar cell. Unlike conventional single layer AR coatings such as ZnS, Sb2O3, SiO or double layer AR coatings such as ZnS/MgF2 deposited by e-beam or resistive evaporation, this oxide preserves the stoichiometry of the InP surface. We show that it is possible to design a three-layer AR coating for a thermally diffused InP solar cell using the In(PO3)3 grown oxide as the first layer and Al2O3 and MgF2 as the second and third layers respectively, so as to yield an overall theoretical reflectance of less than 2%. Since chemical oxides are readily grown on III-V semiconductors materials, the technique of using the grown oxide layer to both passivate the surface as well as serve as the first of a multilayer AR coating should work well for all III-V compound-based solar cells.

Moulot, Jacques; Faur, M.; Faur, M.; Goradia, C.; Goradia, M.; Bailey, S.

1995-01-01

86

Design of a Three-Layer Antireflection Coating for High Efficiency Indium Phosphide Solar Cells Using a Chemical Oxide as First Layer  

NASA Technical Reports Server (NTRS)

It is well known that the behavior of III-V compound based solar cells is largely controlled by their surface, since the majority of light generated carriers (63% for GaAs and 79% for InP) are created within 0.2 microns of the illuminated surface of the cell. Consequently, the always observed high surface recombination velocity (SRV) on these cells is a serious limiting factor for their high efficiency performance, especially for those with the p-n junction made by either thermal diffusion or ion implantation. A good surface passivation layer, ideally, a grown oxide as opposed to a deposited one, will cause a significant reduction in the SRV without adding interface problems, thus improving the performance of III-V compound based solar cells. Another significant benefit to the overall performance of the solar cells can be achieved by a substantial reduction of their large surface optical reflection by the use of a well designed antireflection (AR) coating. In this paper, we demonstrate the effectiveness of using a chemically grown, thermally and chemically stable oxide, not only for surface passivation but also as an integral part of a 3- layer AR coating for thermally diffused p(+)n InP solar cells. A phosphorus-rich interfacial oxide, In(PO3)3, is grown at the surface of the p(+) emitter using an etchant based on HNO3, o-H3PO4 and H2O2. This oxide has the unique properties of passivating the surface as well as serving as a fairly efficient antireflective layer yielding a measured record high AM0, 25 C, open-circuit voltage of 890.3 mV on a thermally diffused InP(Cd,S) solar cell. Unlike conventional single layer AR coatings such as ZnS, Sb2O3, SiO or double layer AR coatings such as ZnS/MgF2 deposited by e-beam or resistive evaporation, this oxide preserves the stoichiometry of the InP surface. We show that it is possible to design a three-layer AR coating for a thermally diffused InP solar cell using the In(PO3)3 grown oxide as the first layer and Al2O3, MgF2 or ZnS, MgF2 as the second and third layers respectively, so as to yield an overall theoretical reflectance of less than 2%. Since chemical oxides are readily grown on III-V semiconductor materials, the technique of using the grown oxide layer to both passivate the surface as well as serve as the first of a multilayer AR coating, should work well for essentially all III-V compound-based solar cells.

Moulot, Jacques; Faur, Mircea; Faur, Maria; Goradia, Chandra; Goradia, Manju; Bailey, Sheila

1995-01-01

87

Magnetron sputtered zinc oxide nanorods as thickness-insensitive cathode interlayer for perovskite planar-heterojunction solar cells.  

PubMed

Suitable electrode interfacial layers are essential to the high performance of perovskite planar heterojunction solar cells. In this letter, we report magnetron sputtered zinc oxide (ZnO) film as the cathode interlayer for methylammonium lead iodide (CH3NH3PbI3) perovskite solar cell. Scanning electron microscopy and X-ray diffraction analysis demonstrate that the sputtered ZnO films consist of c-axis aligned nanorods. The solar cells based on this ZnO cathode interlayer showed high short circuit current and power conversion efficiency. Besides, the performance of the device is insensitive to the thickness of ZnO cathode interlayer. Considering the high reliability and maturity of sputtering technique both in lab and industry, we believe that the sputtered ZnO films are promising cathode interlayers for perovskite solar cells, especially in large-scale production. PMID:25405518

Liang, Lusheng; Huang, Zhifeng; Cai, Longhua; Chen, Weizhong; Wang, Baozeng; Chen, Kaiwu; Bai, Hua; Tian, Qingyong; Fan, Bin

2014-12-10

88

Anti-reflection zinc oxide nanocones for higher efficiency thin-film silicon solar cells  

E-print Network

Thin film silicon solar cells, which are commonly made from microcrystalline silicon ([mu]c-Si) or amorphous silicon (a-Si), have been considered inexpensive alternatives to thick polycrystalline silicon (polysilicon) solar ...

Mailoa, Jonathan P

2012-01-01

89

InP (Indium Phosphide): Into the future  

NASA Technical Reports Server (NTRS)

Major industry is beginning to be devoted to indium phosphide and its potential applications. Key to these applications are high speed and radiation tolerance; however the high cost of indium phosphide may be an inhibitor to progress. The broad applicability of indium phosphide to many devices will be discussed with an emphasis on photovoltaics. Major attention is devoted to radiation tolerance and means of reducing cost of devices. Some of the approaches applicable to solar cells may also be relevant to other devices. The intent is to display the impact of visionary leadership in the field and enable the directions and broad applicability of indium phosphide.

Brandhorst, Henry W., Jr.

1989-01-01

90

Thin film cadmium telluride, zinc telluride, and mercury zinc telluride solar cells. Final subcontract report, 1 July 1988--31 December 1991  

SciTech Connect

This report describes research to demonstrate (1) thin film cadmium telluride solar cells with a quantum efficiency of 75% or higher at 0. 44 {mu}m and a photovoltaic efficiency of 11.5% or greater, and (2) thin film zinc telluride and mercury zinc telluride solar cells with a transparency to sub-band-gap radiation of 65% and a photovoltaic conversion efficiency of 5% and 8%, respectively. Work was directed at (1) depositing transparent conducting semiconductor films by solution growth and metal-organic chemical vapor deposition (MOCVD) technique, (2) depositing CdTe films by close-spaced sublimation (CSS) and MOCVD techniques, (3) preparing and evaluating thin film CdTe solar cells, and (4) preparing and characterizing thin film ZnTe, CD{sub 1-x}Zn{sub 1-x}Te, and Hg{sub 1-x}Zn{sub x}Te solar cells. The deposition of CdS films from aqueous solutions was investigated in detail, and their crystallographic, optical, and electrical properties were characterized. CdTe films were deposited from DMCd and DIPTe at 400{degrees}C using TEGa and AsH{sub 3} as dopants. CdTe films deposited by CSS had significantly better microstructures than those deposited by MOCVD. Deep energy states in CdTe films deposited by CSS and MOCVD were investigated. Thin films of ZnTe, Cd{sub 1- x}Zn{sub x}Te, and Hg{sub 1-x}Zn{sub x}Te were deposited by MOCVD, and their crystallographic, optical, and electrical properties were characterized. 67 refs.

Chu, T.L. [University of South Florida, Tampa, FL (United States)

1992-04-01

91

Window structure for passivating solar cells based on gallium arsenide  

NASA Technical Reports Server (NTRS)

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.

Barnett, Allen M. (Inventor)

1985-01-01

92

Quantum dot-sensitized solar cells based on directly adsorbed zinc copper indium sulfide colloids.  

PubMed

Heavy metal-based quantum dots (QDs) have been demonstrated to behave as efficient sensitizers in QD-sensitized solar cells (QDSSCs), as attested by the countless studies and encouraging efficiencies reported so far. However, their intrinsic toxicity has arisen as a major issue for the prospects of commercialization. Here, we examine the potential of environmentally friendly zinc copper indium sulfide (ZCIS) QDs for the fabrication of liquid-junction QDSSCs by means of photoelectrochemical measurements. A straightforward approach to directly adsorb ZCIS QDs on TiO2 from a colloidal dispersion is presented. Incident photon-to-current efficiency (IPCE) spectra of sensitized photoanodes show a marked dependence on adsorption time, with longer times leading to poorer performances. Cyclic voltammograms point to a blockage of the channels of the mesoporous TiO2 film by the agglomeration of QDs as the main reason for the decrease in efficiency. Photoanodes were also subjected to the ZnS treatment. Its effects on electron recombination with the electrolyte are analyzed through electrochemical impedance spectroscopy and photopotential measurements. The corresponding results bring out the role of the ZnS coating as a barrier layer in preventing electron leakage toward the electrolyte, as argued in other QD-sensitized systems. The beneficial effect of the ZnS coating is ultimately reflected in the power conversion efficiency of complete devices, reaching values of 2%. In a more general vein, through these findings, we aim to call the attention to the potentiality of this quaternary alloy, virtually unexplored as a light harvester for sensitized devices. PMID:24700258

Guijarro, Nstor; Guilln, Elena; Lana-Villarreal, Teresa; Gmez, Roberto

2014-05-21

93

Novel nanostructure zinc zirconate, zinc oxide or zirconium oxide pastes coated on fluorine doped tin oxide thin film as photoelectrochemical working electrodes for dye-sensitized solar cell.  

PubMed

Zinc zirconate (ZnZrO(3)) (ZZ), zinc oxide (ZnO) (ZO) and zirconium oxide (ZrO(2)) (ZRO) nano-particles were synthesized by simple sol-gel method. ZZ, ZO and ZRO nano-particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). Nanoporous ZZ, ZO and ZRO thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)(3)](PF(6))(2), [Co(pby)(3)](PF(6))(3), LiClO(4), and 4-tert-butylpyridine (TBP). The properties of DSSC have been studied by measuring their short-circuit photocurrent density (Jsc), open-circuit voltage (VOC) and fill factor (ff). The application of ZnZrO(3) as working electrode produces a significant improvement in the fill factor (ff) of the dye-sensitized solar cells (ff=56%) compared to ZnO working electrode (ff=40%) under the same condition. PMID:23266694

Hossein Habibi, Mohammad; Askari, Elham; Habibi, Mehdi; Zendehdel, Mahmoud

2013-03-01

94

Novel nanostructure zinc zirconate, zinc oxide or zirconium oxide pastes coated on fluorine doped tin oxide thin film as photoelectrochemical working electrodes for dye-sensitized solar cell  

NASA Astrophysics Data System (ADS)

Zinc zirconate (ZnZrO3) (ZZ), zinc oxide (ZnO) (ZO) and zirconium oxide (ZrO2) (ZRO) nano-particles were synthesized by simple sol-gel method. ZZ, ZO and ZRO nano-particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). Nanoporous ZZ, ZO and ZRO thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)3](PF6)2, [Co(pby)3](PF6)3, LiClO4, and 4-tert-butylpyridine (TBP). The properties of DSSC have been studied by measuring their short-circuit photocurrent density (Jsc), open-circuit voltage (VOC) and fill factor (ff). The application of ZnZrO3 as working electrode produces a significant improvement in the fill factor (ff) of the dye-sensitized solar cells (ff = 56%) compared to ZnO working electrode (ff = 40%) under the same condition.

Hossein Habibi, Mohammad; Askari, Elham; Habibi, Mehdi; Zendehdel, Mahmoud

2013-03-01

95

Design and fabrication of anti-reflection coating on Gallium Phosphide, Zinc Selenide and Zinc Sulfide substrates for visible and infrared application  

NASA Astrophysics Data System (ADS)

Results of design and fabrication of a dual-band anti-reflection coating on a gallium phosphide (GaP), zinc selenide (ZnSe) and zinc sulfide (ZnS) substrates are presented. A multilayer stack structure of antireflection coatings made of zinc sulfide and yttrium fluoride (YF3) was theoretically designed for optical bands between 0.8 and 0.9 ?m and between 9.5 and 10.5 ?m. This stack was designed as efficient for these materials (GaP, ZnS, ZnSe) together. Multilayer stack structure was deposited using thermal evaporation method. Theoretically predicted transmittance spectra were compared with transmitted spectra measured on coated substrates. Efficiency of anti-reflection coating is estimated and discrepancies are analyzed and discussed.

Vpenka, D.; Vclavk, J.; Mokr, P.

2013-04-01

96

Efficient inverted polymer solar cells based on ultrathin aluminum interlayer modified aluminum-doped zinc oxide electrode  

NASA Astrophysics Data System (ADS)

A convenient and economical design for inverted polymer solar cells has been developed by introducing an ultrathin aluminium (Al) interlayer to modify aluminum-doped zinc oxide (AZO) electrode as the bottom cathode. An ultrathin interlayer of Al could lower the work function of AZO electrode. Power conversion efficiency (PCE) of 3.84% was obtained for poly(3-hexyl-thiophene):phenyl-C61-butyric acid methyl ester based device and that of poly(3-hexyl-thiophene):indene-C60 bisadduct based device with such electrodes could reach to 5.52%, which was much higher than the structurally identical device based on ITO/Al(1 nm) electrode and almost the same as that of the conventional device. This indicates that the ultrathin Al modified AZO composite electrode is a strong competitor for the cathode in inverted polymer solar cells especially the large scale and low costs devices.

Shi, Ting; Zhu, Xiaoguang; Tu, Guoli

2014-03-01

97

High resistivity zinc stannate as a buffer layer in cds\\/cdte solar cells  

Microsoft Academic Search

The electrical conductivity of transparent conducting oxides is well exploited in front surface electrodes for solar cells where high transmission is also important. Fluorine doped tin oxide (SnO2: F) is the most popular choice of front contacts for CdTe solar cells. In this thesis, Cd2SnO4 and Zn2SnO4 thin films are investigated focusing on their electrical and optical properties and used

Sudhakar R Gayam

2005-01-01

98

Solar Energy Materials & Solar Cells 91 (2007) 924930 Plasma-enhanced chemical vapor deposition of zinc oxide at  

E-print Network

Solar Energy Materials & Solar Cells 91 (2007) 924­930 Plasma-enhanced chemical vapor deposition.F. Hicks? Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Box W=cm3 RF power, and 225 1C. The average aluminum concentration in the ZnO film was 5:4 ? 1020 cm?3

Hicks, Robert F.

99

Theoretical screening of novel alkyne bridged zinc porphyrins as sensitizer candidates for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Alkyne bridged porphyrin sensitizers have attracted great attention in the field of dye-sensitized solar cells (DSSCs) because of their excellent photo-to-electric conversion efficiencies, among which YD2 has reached 11% while YD2-o-C8 has reached 11.9% solely and 12.3% co-sensitized with other sensitizers. Design and screening of porphyrin sensitizer candidates with wider electronic absorption spectra to further improve the photo-to-electric conversion efficiencies of corresponding solar cells is still very important. Twenty novel alkyne bridged zinc porphyrin sensitizer candidates composed of the donors diarylamino-, tri-4-methylphenyl-, tri-hydroxyl- and tri-amino-substituted zinc porphyrins as well as the selected acceptors E, M, Q, R and S have been designed and calculated at the density functional B3LYP level. YD2 and YD2-o-C8 are also calculated at the same level for comparison. The result shows that the sensitizer candidates all have smaller HOMO-LUMO gaps as well as wider and red-shifted absorption bands than those of YD2 and YD2-o-C8. Most of the sensitizer candidates have appropriate HOMO and LUMO energy levels relative to the redox potential of the mediator and the TiO2 conduction band, showing that they are promising to provide comparable or even higher photo-to-electric conversion efficiencies than 11% of YD-2 or 11.9% of YD2-o-C8.

Zhang, Xianxi; Du, Yuchang; Chen, Qianqian; Sun, Huafei; Pan, Tingting; Hu, Guiqi; Ma, Ruimin; Sun, Yuanwei; Li, Dacheng; Dou, Jianmin; Pan, Xu

2014-12-01

100

Theoretical screening of novel alkyne bridged zinc porphyrins as sensitizer candidates for dye-sensitized solar cells.  

PubMed

Alkyne bridged porphyrin sensitizers have attracted great attention in the field of dye-sensitized solar cells (DSSCs) because of their excellent photo-to-electric conversion efficiencies, among which YD2 has reached 11% while YD2-o-C8 has reached 11.9% solely and 12.3% co-sensitized with other sensitizers. Design and screening of porphyrin sensitizer candidates with wider electronic absorption spectra to further improve the photo-to-electric conversion efficiencies of corresponding solar cells is still very important. Twenty novel alkyne bridged zinc porphyrin sensitizer candidates composed of the donors diarylamino-, tri-4-methylphenyl-, tri-hydroxyl- and tri-amino-substituted zinc porphyrins as well as the selected acceptors E, M, Q, R and S have been designed and calculated at the density functional B3LYP level. YD2 and YD2-o-C8 are also calculated at the same level for comparison. The result shows that the sensitizer candidates all have smaller HOMO-LUMO gaps as well as wider and red-shifted absorption bands than those of YD2 and YD2-o-C8. Most of the sensitizer candidates have appropriate HOMO and LUMO energy levels relative to the redox potential of the mediator and the TiO2 conduction band, showing that they are promising to provide comparable or even higher photo-to-electric conversion efficiencies than 11% of YD-2 or 11.9% of YD2-o-C8. PMID:24983919

Zhang, Xianxi; Du, Yuchang; Chen, Qianqian; Sun, Huafei; Pan, Tingting; Hu, Guiqi; Ma, Ruimin; Sun, Yuanwei; Li, Dacheng; Dou, Jianmin; Pan, Xu

2014-12-10

101

Single-crystalline zinc oxide nanowires as photoanode material for dye-sensitized solar cells.  

PubMed

This study reports the use of single-crystalline and well-aligned ZnO nanowires as photoanode material for dye-sensitized solar cells. The ZnO nanowires are grown on fluorine-doped tin oxide coated glass substrates without catalysts by thermal evaporation. In spite of low roughness factors of around 25 for the nanowire photoanodes, the fabricated solar cells yield power conversion efficiencies of around 1.3% under AM 1.5G (100 mW cm-2) illumination. Moreover, fill factors of around 0.5 have been achieved and are relatively high when compared with reported values from ZnO nanowire photoanodes. The results reveal the advantage of using single-crystalline nanowires as photoanode material and provide clues for the advancement of nanowire based dye-sensitized solar cells. PMID:21137749

Ho, Shu-Te; Hsiao, Ching-Lun; Lin, Hsin-Yu; Chen, Hsiang-An; Wang, Chiu-Yen; Lin, Heh-Nan

2010-10-01

102

Synthesis of zinc phthalocyanine with large steric hindrance and its photovoltaic performance for dye-sensitized solar cells.  

PubMed

A zinc phthalocyanine (ZnPc) derivative (Zn-tri-PcNc-8) containing tri-benzonaphtho-condensed porphyrazine with one carboxylic and six diphenylphenoxy peripheral substitutions was designed and synthesized as a sensitizer for dye-sensitized solar cells (DSSCs). For the purpose of extending the absorption spectra while minimizing the formation of ZnPc molecular aggregates, bulky 2,6-diphenylphenoxy groups were used as electron donor moieties, and the carboxylic group as an anchoring group to graft the sensitizer onto the semiconductor. It was found that a TiO2-based solar cell sensitized by Zn-tri-PcNc-8 shows a maximum incident photon-to-current conversion efficiency in the red/near-IR light range (650-750 nm), and a solar cell sensitized at near room temperature (30 C) for 48 h exhibits the best efficiency (3.01%). The efficiency was much higher than that (1.96%) for a solar cell sensitized by its analogue (Zn-tri-PcNc-2) having one carboxyl and three tert-butyl groups without chenodeoxycholic acid (CDCA), indicating that the introduction of six bulky diphenylphenoxy substitutions with large steric hindrance in the ZnPc macrocycle can effectively suppress the molecular aggregates, thus resulting in an improved conversion efficiency. The present results shed light on an effective solution to adjust the ZnPc property via chemical modification such as changing the "push-pull" effect and adding large steric hindrance substituents to further improve the efficiency of the phthalocyanine-sensitized solar cell. PMID:25716344

Lin, Li; Peng, Bosi; Shi, Wenye; Guo, Yingying; Li, Renjie

2015-03-10

103

ZINC ROUGHER CELLS ON LEFT, ZINC CLEANER CELLS ON RIGHT, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

ZINC ROUGHER CELLS ON LEFT, ZINC CLEANER CELLS ON RIGHT, LOOKING NORTH. NOTE ONE STYLE OF DENVER AGITATOR IN LOWER RIGHT CELL. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

104

Enhancing the efficiency of SnS solar cells via band-offset engineering with a zinc oxysulfide buffer layer  

NASA Astrophysics Data System (ADS)

SnS is a promising earth-abundant material for photovoltaic applications. Heterojuction solar cells were made by vapor deposition of p-type tin(II) sulfide, SnS, and n-type zinc oxysulfide, Zn(O,S), using a device structure of soda-lime glass/Mo/SnS/Zn(O,S)/ZnO/ITO. A record efficiency was achieved for SnS-based thin-film solar cells by varying the oxygen-to-sulfur ratio in Zn(O,S). Increasing the sulfur content in Zn(O,S) raises the conduction band offset between Zn(O,S) and SnS to an optimum slightly positive value. A record SnS/Zn(O,S) solar cell with a S/Zn ratio of 0.37 exhibits short circuit current density (Jsc), open circuit voltage (Voc), and fill factor (FF) of 19.4 mA/cm2, 0.244 V, and 42.97%, respectively, as well as an NREL-certified total-area power-conversion efficiency of 2.04% and an uncertified active-area efficiency of 2.46%.

Sinsermsuksakul, Prasert; Hartman, Katy; Bok Kim, Sang; Heo, Jaeyeong; Sun, Leizhi; Hejin Park, Helen; Chakraborty, Rupak; Buonassisi, Tonio; Gordon, Roy G.

2013-02-01

105

Cds\\/cdte thin film solar cells with zinc stannate buffer layer  

Microsoft Academic Search

CdS\\/CdTe solar cell performance and reproducibility can be improved by integrating a ZTO buffer layer, which interdiffuses into the CdS layer during device fabrication. Reducing the thickness of CdS layer improves the QE in the blue spectral region without affecting the device performance. This buffer layer is expected to prevent the formation of localized TCO\\/CdTe junction during high temperature processing.The

Srilatha Bapanapalli

2005-01-01

106

Comparative Study on the Effectiveness of Coumavec and Zinc Phosphide in Controlling Zoonotic Cutaneous Leishmaniasis in a Hyperendemic Focus in Central Iran  

PubMed Central

Background Zoonotic cutaneous leishmaniasis (ZCL) is an increasing health problems in many rural areas of Iran. The aim of this study was to introduce a new alternative rodenticide to control the reservoirs of ZCL, its effect on the vector density and the incidence of the disease in hyperendemic focus of Esfahan County, central Iran. Methods: The study was carried out from January 2011 to January 2012. In intervention areas, rodent control operation was conducted using zinc phosphide or Coumavec. Active case findings were done by house-to-house visits once every season during 20112012. To evaluate the effect of rodent control operation on the vector density, sand flies were collected twice a month using sticky traps. Results: The reduction rate of rodent holes in intervention areas with Coumavec and zinc phosphide were 48.46% and 58.15% respectively, whereas in control area results showed 6.66 folds intensification. The Incidence of ZCL significantly reduced in the treated areas. Totally, 3200 adult sand flies were collected and identified in the intervention and control areas. In the treated area with zinc phosphide, the density of Phlebotomus papatasi was higher in outdoors in contrast with the treated area by Coumavec which the density of the sand fly was higher in indoors. Conclusion: Both rodenticides were effective on the incidence of ZCL and the population of the reservoirs as well. Coumavec seems to be effective on the outdoor density of the vector. This combination of rodenticide-insecticide could be a suitable alternative for zinc phosphide while bait shyness or behavioral resistance is occurred. PMID:23293775

Veysi, A; Vatandoost, H; Yaghoobi-Ershadi, MR; Arandian, MH; Jafari, R; Hosseini, M; abdoli, H; Rassi, Y; Heidari, K; Sadjadi, A; Fadaei, R; Ramazanpour, J; Aminian, K; Shirzadi, MR; Akhavan, AA

2012-01-01

107

Zinc oxide modified with benzylphosphonic acids as transparent electrodes in regular and inverted organic solar cell structures  

NASA Astrophysics Data System (ADS)

An approach is presented to modify the work function of solution-processed sol-gel derived zinc oxide (ZnO) over an exceptionally wide range of more than 2.3 eV. This approach relies on the formation of dense and homogeneous self-assembled monolayers based on phosphonic acids with different dipole moments. This allows us to apply ZnO as charge selective bottom electrodes in either regular or inverted solar cell structures, using poly(3-hexylthiophene):phenyl-C71-butyric acid methyl ester as the active layer. These devices compete with or even surpass the performance of the reference on indium tin oxide/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate. Our findings highlight the potential of properly modified ZnO as electron or hole extracting electrodes in hybrid optoelectronic devices.

Lange, Ilja; Reiter, Sina; Kniepert, Juliane; Piersimoni, Fortunato; Ptzel, Michael; Hildebrandt, Jana; Brenner, Thomas; Hecht, Stefan; Neher, Dieter

2015-03-01

108

Salicylic acid as a tridentate anchoring group for azo-bridged zinc porphyrin in dye-sensitized solar cells.  

PubMed

Two series dyes of azo-bridged zinc porphyrins have been devised, synthesized, and performed in dye-sensitized solar cells, in which salicylic acids and azo groups were introduced as a new anchoring group and ?-conjugated bridge via a simple synthetic procedure. The representation of the new dyes has been investigated by optical, photovoltaic, and electrochemical means. The photoelectric conversion efficiency of their DSSC devices has been improved compared with other DSSC devices sensitized by symmetrical porphyrin dyes. The results revealed that tridentate binding modes between salicylic acid and TiO2 nanoparticles could enhance the efficiency of electron injection. The binding modes between salicylic acid and TiO2 nanoparticles may play a crucial role in the photovoltaic performance of DSSCs. PMID:24229086

Gou, Faliang; Jiang, Xu; Li, Bo; Jing, Huanwang; Zhu, Zhenping

2013-12-11

109

Urchin-inspired zinc oxide as building blocks for nanostructured solar cells  

E-print Network

High surface area nanowire based architectures have been identified as important components for future optoelectronic nanodevices, solar cells, wettability coatings, gas sensors, and biofuel cells. Here we report on a novel urchin-inspired nanowire architecture: its interwoven three-dimensional, high-surface-area nanowire arrangement can be precisely controlled by using a low-cost and scalable synthesis based on a combination of nanosphere lithography, low-temperature atomic layer deposition, and electrodeposition. The performance of single-layer arrays of urchin-inspired ZnO nanowire building blocks competes to that of planar nanowire carpets. We illustrate this capability by fabricating fully-inorganic extremely thin absorber solar cells using CdSe as absorber and CuSCN as hole-collector material. The light diffusion of the urchin-inspired nanowire arrays was varied from 15% to 35%. Homogenous absorption in the wavelength range of 400-800 nm of up to 90% was obtained. Solar conversion efficiencies of ~ 1.33...

Elias, Jamil; Utke, Ivo; Erni, Rolf; Hosseini, Davood; Michler, Johann; Philippe, Laetitia

2012-01-01

110

High efficiency cadmium telluride and zinc telluride based thin-film solar cells  

SciTech Connect

This report describes work to improve the basic understanding of CdTe and ZnTe alloys by growing and characterizing these films along with cell fabrication. The major objective was to develop wide-band-gap (1.6--1.8 eV) material for the top cell, along with compatible window material and transparent ohmic contacts, so that a cascade cell design can be optimized. Front-wall solar cells were fabricated with a glass/SnO{sub 2}/CdS window, where the CdS film is thin to maximize transmission and current. Wide-band-gap absorber films (E{sub g} = 1.75 eV) were grown by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD) techniques, which provided excellent control for tailoring the film composition and properties. CdZnTe films were grown by both MBE and MOCVD. All the as-grown films were characterized by several techniques (surface photovoltage spectroscopy, Auger electron spectroscopy (AES), and x-ray photoelectron spectroscopy (XPS)) for composition, bulk uniformity, thickness, and film and interface quality. Front-wall-type solar cells were fabricated in collaboration with Ametek Materials Research Laboratory using CdTe and CdZnTe polycrystalline absorber films. The effects of processing on ternary film were studied by AES and XPS coupled with capacitance voltage and current voltage measurements as a function of temperature. Bias-dependent spectral response and electrical measurements were used to test some models in order to identify and quantify dominant loss mechanisms.

Rohatgi, A.; Sudharsanan, R.; Ringel, S.A.; Chou, H.C. (Georgia Inst. of Tech., Atlanta, GA (United States))

1992-10-01

111

Magnetron sputtered zinc stannate films for silicon thin film solar cells  

Microsoft Academic Search

Zinc stannate films have been prepared by RF magnetron sputtering using a ZnO:SnO\\/sub 2\\/-target with 33 at.% SnO\\/sub 2\\/. The influence of total pressure and substrate temperature on the electrical film properties was studied. A minimum resistivity of 2.9\\/spl times\\/10\\/sup -3\\/ \\/spl Omega\\/cm could be achieved. All zinc stannate films exhibit amorphous structure independent of the deposition conditions. The stability

O. Kluth; C. Agashe; J. Hupkes; J. Muller; B. Rech

2003-01-01

112

High-efficiency cadmium and zinc-telluride-based thin-film solar cells  

SciTech Connect

This report describes research into polycrystalline CdTe solar cells grown by metal-organic chemical vapor deposition. Efficiencies of {approximately}10% were achieved using both p-i-n and p-n structures. A pre-heat treatment of CdS/SnO{sub 2}/glass substrates at 450{degrees}C in hydrogen atmosphere prior to the CdTe growth was found to be essential for high performance because this heat treatment reduces oxygen-related defects from the CdS surface. However, this treatment also resulted in a Cd-deficient CdS surface, which may in part limit the CdTe cell efficiency to 10% due to Cd vacancy-related interface defects. Preliminary model calculations suggest that removing these states can increase the cell efficiency from 10% to 13.5%. Photon absorption in the CdS film also limits the cell performance, and eliminating this loss mechanism can result in CdTe efficiencies in excess of 18%. Polycrystalline, 1.7-e, CdZnTe films were also grown for tandem-cell applications. CdZnTe/CdS cells processed using the standard CdTe cell fabrication procedure resulted in 4.4% efficiency, high series resistance, and a band-gap shift to 1.55 eV. The formation of Zn-O at and near the CdZnTe surface is the source of high contact resistance. A saturated dichromate each prior to contact deposition was found to solve the contact resistance problem. The CdCl{sub 2} treatment was identified as the cause of the observed band-gap shift due to the preferred formation of ZnCl{sub 2}. 59 refs.

Rohatgi, A.; Sudharsanan, R.; Ringel, S. (Georgia Inst. of Tech., Atlanta, GA (United States))

1992-02-01

113

Microwave assisted synthesis of zinc stannate nanocubes for dye sensitized solar cell application  

NASA Astrophysics Data System (ADS)

The ternary complex oxide Zn2SnO4 (ZS) has become more essential because of its photonic energy conversion, tremendous stability and higher electron mobility compared to the binary counterparts. The ZS nanocubes were prepared by simple microwave assisted route. The cubic spinel structured ZS was confirmed by X-ray diffraction (XRD) and micro-Raman techniques. Scanning electron micrograph revealed the formation of nanocubes with size of ?90 nm. The Dye Sensitized Solar Cells (DSSCs) were fabricated using the synthesized ZS as photoanode and low cost organic dyes such as Rose Bengal (RB), Eosin Yellow (EY) and Fluorescein sodium salt (FY) as sensitizers to study their light conversion efficiencies. The DSSCs exhibited power conversion efficiency (PCE) of 0.64%, 0.05% and 0.02% for RB, EY and FY sensitized films, respectively.

Jayabal, P.; Sasirekha, V.; Mayandi, J.; Ramakrishnan, V.

2014-11-01

114

A review of episodes of zinc phosphide toxicosis in wild geese (Branta spp.) in Oregon (2004-2011).  

PubMed

Epizootic mortality in several geese species, including cackling geese (Branta hutchinsii) and Canada geese (Branta canadensis), has been recognized in the Willamette Valley of Oregon for over a decade. Birds are generally found dead on a body of water or are occasionally observed displaying neurologic clinical signs such as an inability to raise or control the head prior to death. Investigation of these epizootic mortality events has revealed the etiology to be accidental poisoning with the rodenticide zinc phosphide (Zn(3)P(2)). Gross and histologic changes are restricted to acute pulmonary congestion and edema, sometimes accompanied by distension of the upper alimentary tract by fresh grass. Geese are unusually susceptible to this pesticide; when combined with an epidemiologic confluence of depredation of specific agricultural crops by rodents and seasonal avian migration pathways, epizootic toxicosis may occur. Diagnosis requires a high index of suspicion, appropriate sample collection and handling, plus specific test calibration for this toxicant. Interagency cooperation, education of farmers regarding pesticide use, and enforcement of regulations has been successful in greatly decreasing these mortality events since 2009. PMID:23293161

Bildfell, Rob J; Rumbeiha, Wilson K; Schuler, Krysten L; Meteyer, Carol U; Wolff, Peregrine L; Gillin, Colin M

2013-01-01

115

A review of episodes of zinc phosphide toxicosis in wild geese (Branta spp.) in Oregon (2004?2011)  

USGS Publications Warehouse

Epizootic mortality in several geese species, including cackling geese (Branta hutchinsii) and Canada geese (Branta canadensis), has been recognized in the Willamette Valley of Oregon for over a decade. Birds are generally found dead on a body of water or are occasionally observed displaying neurologic clinical signs such as an inability to raise or control the head prior to death. Investigation of these epizootic mortality events has revealed the etiology to be accidental poisoning with the rodenticide zinc phosphide (Zn3P2). Gross and histologic changes are restricted to acute pulmonary congestion and edema, sometimes accompanied by distension of the upper alimentary tract by fresh grass. Geese are unusually susceptible to this pesticide; when combined with an epidemiologic confluence of depredation of specific agricultural crops by rodents and seasonal avian migration pathways, epizootic toxicosis may occur. Diagnosis requires a high index of suspicion, appropriate sample collection and handling, plus specific test calibration for this toxicant. Interagency cooperation, education of farmers regarding pesticide use, and enforcement of regulations has been successful in greatly decreasing these mortality events since 2009.

Bildfell, Rob J.; Rumbeiha, Wilson K.; Schuler, Krysten L.; Meteyer, Carol U.; Wolff, Peregrine L.; Gillin, Colin M.

2013-01-01

116

Synthesis and characterisation of Copper Zinc Tin Sulphide (CZTS) compound for absorber material in solar-cells  

NASA Astrophysics Data System (ADS)

The development of thin-film semiconductor compounds, such as Copper Indium Gallium Selenide (CIGS), has caused remarkable progress in the field of thin-film photovoltaics. However, the scarcity and the increasing prices of indium impose the hunt for alternative materials. The Copper Zinc Tin Sulphide (CZTS) is one of the promising emerging materials with Kesterite-type crystal structure and favourable material properties like high absorption co-efficient and direct band-gap. Moreover, all the constituent elements of CZTS are non-toxic and aplenty on the earth-crust, making it a potential candidate for the thin-film photovoltaics. Here we report the synthesis of CZTS powder from its constituent elements, viz. copper, zinc, tin and sulphur, in an evacuated Quartz ampoule at 1030 K temperature. The sulphur content in the raw mixture in the ampoule was varied and optimised in order to attain the desired atomic stoichiometry of the compound. The synthesised powder was characterised by X-Ray diffraction technique (XRD), Raman Scattering Spectroscopy, Energy Dispersive Analysis of X-Ray (EDAX) and UV-Visible Absorption Spectra. The XRD Patterns of the synthesised compound show the preferred orientation of (112), (220) and (312) planes, confirming the Kesterite structure of CZTS. The chemical composition of the powder was analysed by EDAX and shows good atomic stoichiometry of the constituent elements in the CZTS compound. The UV-Vis absorption spectra confirm the direct band-gap of about 1.45 eV, which is quite close to the optimum value for the semiconductor material as an absorber in solar-cells.

Kheraj, Vipul; Patel, K. K.; Patel, S. J.; Shah, D. V.

2013-01-01

117

Efficient inverted polymer solar cells using low-temperature zinc oxide interlayer processed from aqueous solution  

NASA Astrophysics Data System (ADS)

In this work, an aqueous solution method that entails processing at low temperatures is utilized to deposit a ZnO interlayer in poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl C61 butyric acid methyl ester-based inverted polymer solar cells (PSCs). The effect of ZnO annealing temperature from 50 to 150 C on PSC performance is systemically studied and it is found that the transition point is approximately 80 C. When the ZnO annealing temperature is higher than 80 C, PSCs show similar current densityvoltage (JV) characteristics and achieve a power conversion efficiency higher than 3.5%. Transmittance spectrum, PL spectrum, and surface morphology studies show that an annealing temperature above 80 C is sufficient for ZnO to achieve a relatively good quality, and that a higher temperature only slightly improves ZnO quality, which is confirmed from statistical results. Furthermore, flexible PSCs based on PET substrates show a comparable power conversion efficiency and good flexibility.

Chen, Dazheng; Zhang, Chunfu; Heng, Ting; Wei, Wei; Wang, Zhizhe; Han, Genquan; Feng, Qian; Hao, Yue; Zhang, Jincheng

2015-04-01

118

Dye-sensitized solar cell characteristics of nanocomposite zinc ferrite working electrode: effect of composite precursors and titania as a blocking layer on photovoltaic performance.  

PubMed

This research investigates the performance of a zinc ferrite (ZF) as working electrodes in a dye-sensitized solar cell (DSSC). This ZF working electrode was prepared by sol-gel and thermal decomposition of four different precursors including: zinc acetate dihydrate (Zn(CH3COO)22H2O), ferric nitrate nonahydrate (Fe(NO3)39H2O), iron(III) acetate; Fe(C2H3O2)3, and zinc nitrate hexahydrate, Zn(NO3)26H2O. The effects of annealing temperature and precursors on the structural, morphological, and optical properties were investigated. The field emission scanning electron microscope images (FESEM) and scanning electron microscopy (SEM) show that ZFe films are polycrystalline in nature and homogeneous with densely packed grains. Nanoporous zinc ferrite coatings were prepared by doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in DSSC. In all DSSCs, platinized FTO and [Co(bpy)3](2+/3+) in 3-methoxy proponitrile were used as counter electrode and redox mediator system respectively. Comparing the fill factors of four different zinc ferrite nanocomposites, the highest fill factor was for ZnFe2O4-TBL sample. Cell fabricated with ZnFeA working electrode shows relatively higher Jsc. PMID:23571086

Habibi, Mohammad Hossein; Habibi, Amir Hossein; Zendehdel, Mahmoud; Habibi, Mehdi

2013-06-01

119

Zinc-Porphyrin Dyes with Different meso-Aryl Substituents for Dye-Sensitized Solar Cells: Experimental and Theoretical Studies.  

PubMed

A series of new zinc-porphyrin dyes that contain different meso substituents (phenyl, carbazole phenyl, and carbazole thiophenyl groups) and bithiophenyl cyanoacrylic acid as the ?-conjugated anchoring moiety were designed, synthesized, and characterized as sensitizers for dye-sensitized solar cells (DSSCs). The effects of these meso substituents on the properties of the porphyrin dyes were theoretically and experimentally investigated. By meso substitution of the porphyrin ring with carbazole-aryl moieties, the short-circuit current (Jsc ) and open-circuit voltage (Voc ) of the DSSCs were improved as was the power conversion efficiency (?) owing to the influence of both the suppression of dye aggregations and the enhanced charge separation and charge-injection efficiency of the dye to TiO2 films. Among these dyes, ZnPCPA made of the carbazole phenyl meso substituents gave rise to the highest ? of 6.24?% (Jsc =13.38?mA?cm(-2) , Voc =0.66?V, and fill factor of 0.71). PMID:25267373

Sirithip, Kanokkorn; Prachumrak, Narid; Rattanawan, Rattanawalee; Keawin, Tinnagon; Sudyoadsuk, Taweesak; Namuangruk, Supawadee; Jungsuttiwong, Siriporn; Promarak, Vinich

2015-04-01

120

Dilute phosphide nitride materials as photocathodes for electrochemical solar energy conversion  

NASA Astrophysics Data System (ADS)

Dilute nitride materials have been used in a variety of III-V photonic devices, but have not been significantly explored in photoelectrochemical applications. This work focuses on using dilute phosphide nitride materials of the form (Al,In)P1-xNx as photocathodes for the generation of hydrogen fuel from solar energy. Heteroepitaxial MOCVD growth of AlPN thin films on GaP yields high quality material with a direct bandgap energy of 2.218 eV. Aligned epitaxial growth of InP and GaP nanowires on InP and Si substrates, respectively, provides a template for designing nanostructured photocathodes over a large area. Electrochemical testing of a AlPN/GaP heterostructure electrode yields up to a sixfold increase in photocurrent enhancement under blue light illumination as compared to a GaP electrode. Additionally, the AlPN/GaP electrodes exhibit no degradation in performance after galvanostatic biasing over time. These results show that (Al,In)P1-xNx is a promising materials system for use in nanoscale photocathode structures.

Parameshwaran, Vijay; Xu, Xiaoqing; Kang, Yangsen; Harris, James; Wong, H.-S. Philip; Clemens, Bruce

2013-03-01

121

Quantum chemical investigations aimed at modeling highly efficient zinc porphyrin dye sensitized solar cells.  

PubMed

Zinc tetraphenylporphyrin (ZnTPP) was modified by a push-pull strategy and then density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were performed for the resulting derivatives. The smallest HOMO-LUMO energy gaps were found in ZnTPP-6 and ZnTPP-7, which had nitro substituents and a conjugated chain, while the largest was observed for ZnTPP-5. The energy gaps of all of the systems designed in this work were smaller than that of ZnTPP. Clear intramolecular charge transfer was observed from donor to acceptor in ZnTPP-6 and ZnTPP-7, which had nitro groups at positions R8, R9, and R10, as well as in ZnTPP-3 and ZnTPP-4, which had cyano groups at those positions. The narrow band gaps (compared to that of ZnTPP) of these designed systems, where the LUMO is above the conduction band of TiO(2) and the HOMO is below the redox couple, indicate that they are efficient sensitizers. The B bands of these newly designed derivatives, except for ZnTPP-5, are redshifted compared with the B band of ZnTPP. PMID:22552753

Irfan, Ahmad; Hina, Naz; Al-Sehemi, Abdullah G; Asiri, Abdullah M

2012-09-01

122

Solution Processing of Cadmium Sulfide Buffer Layer and Aluminum-Doped Zinc Oxide Window Layer for Thin Films Solar Cells  

NASA Astrophysics Data System (ADS)

Cadmium sulfide (CdS) and aluminum-doped zinc oxide (Al:ZnO) thin films are used as buffer layer and front window layer, respectively, in thin film solar cells. CdS and Al:ZnO thin films were produced using chemical bath deposition (CBD) and sol-gel technique, respectively. For CBD CdS, the effect of bath composition and temperature, dipping time and annealing temperature on film properties was investigated. The CdS films are found to be polycrystalline with metastable cubic crystal structure, dense, crack-free surface morphology and the crystallite size of either few nanometers or 12-17 nm depending on bath composition. In case of CdS films produced with 1:2 ratio of Cd and S precursors, spectrophotometer studies indicate quantum confinement effect, owing to extremely small crystallite size, with an increase in Eg value from 2.42 eV (for bulk CdS) to 3.76 eV along with a shift in the absorption edge toward 330 nm wavelength. The optimum annealing temperature is 400C beyond which film properties deteriorate through S evaporation and CdO formation. On the other hand, Al:ZnO films prepared via spin coating of precursor sols containing 0.90-1.10 at.% Al show that, with an increase in Al concentration, the average grain size increases from 28 nm to 131 nm with an associated decrease in root-mean-square roughness. The minimum value of electrical resistivity, measured for the films prepared using 0.95 at.% Al in the precursor sol, is 2.7 10-4 ? ? cm. The electrical resistivity value rises upon further increase in Al doping level due to introduction of lattice defects and Al segregation to the grain boundary area, thus limiting electron transport through it.

Alam, Mahboob; Islam, Mohammad; Achour, Amine; Hayat, Ansar; Ahsan, Bilal; Rasheed, Haroon; Salam, Shahzad; Mujahid, Mohammad

2014-07-01

123

Ohmic contact for P type indium phosphide  

NASA Technical Reports Server (NTRS)

A body including P type indium phosphide has an ohmic contact thereon of an alloy of by weight 81% to 86% gold (Au), 11% to 14% germanium (Ge) and 2% to 5% zinc (Zn). This contact has a low resistance and good adhesion to the indium phosphide body.

Hawrylo, Frank Z. (Inventor)

1980-01-01

124

High efficiency cadmium and zinc telluride-based thin film solar cells  

SciTech Connect

Polycrystalline Cd{sub 1-x}Zn{sub x}Te and Cd{sub 1-x}Mn{sub x}Te films with a band gap of 1.7 eV were successfully grown on glass/SnO{sub 2}/CdS substrates by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD), respectively. Polycrystalline Cd{sub 1-x}Zn{sub x}Te films grown by MBE resulted in uniform composition and sharp interfaces. However, polycrystalline Cd{sub 1-x}Mn{sub x}Te films grown by MOCVD showed nonuniform compositions and evidence of manganese accumulation at the Cd{sub 1-x}Mn{sub x}Te/CdS interface. We found that manganese interdiffuses and replaces cadmium in the CdS film. By improving the CdTe/CdS interface and, thus, reducing the collection function effects, the efficiency of the MOCVD CdTe cell can be improved to about 13.5%. MBE-grown CdTe cells also produced 8%--9% efficiencies. The standard CdTe process was not optimum for ternary films and resulted in a decrease in the band gap. Recent results indicate that CdCl{sub 2} + ZnCl{sub 2} chemical treatment may prevent the band-gap reduction, and that chromate etch (rather than bromine etch) may provide the solution to contact resistance in the ternary cells.

Rohatgi, A.; Summers, C.J.; Erbil, A.; Sudharsanan, R.; Ringel, S. (Georgia Inst. of Tech., Atlanta, GA (USA). School of Electrical Engineering)

1990-10-01

125

Ultrathin amorphous zinc-tin-oxide buffer layer for enhancing heterojunction interface quality in metal-oxide solar cells  

E-print Network

We demonstrate a tunable electron-blocking layer to enhance the performance of an Earth-abundant metal-oxide solar-cell material. A 5 nm thick amorphous ternary metal-oxide buffer layer reduces interface recombination, ...

Heo, Jaeyeong

126

Solar cell  

SciTech Connect

A solar cell and a method of manufacturing the same are disclosed. The solar cell has a semiconducor substrate having a major surface for receiving light, a p-n junction for photovoltatic generation therein and a thin alumina coating layer on the major surface of the semiconductor substrate. The alumina coating layer includes H radicals and OH radicals.

Nakano, H.; Kato, T.; Morita, H.

1984-07-31

127

Zinc Deficiency in Sickle Cell Disease  

E-print Network

Clinical similarities between patients with sickle cell anemia and zinc-deficient subjects suggested a secon-dary zinc deficiency in sickle cell anemia. Zinc was as-sayed in various biological fluids and tissues by atomic absorption spectrophotometry. Zinc in the plasma, erythrocytes, and hair was

A S. Prasad; Eric B. Schoomaker; Jesus Ortega; George J. Brewer; Donald Oberleas; Fred J. Oelshlegel

1974-01-01

128

Gallium phosphide energy converters  

NASA Technical Reports Server (NTRS)

Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/sq cm have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.

Sims, P. E.; Dinetta, L. C.; Goetz, M. A.

1995-01-01

129

Zinc Oxide Modified with Benzylphosphonic Acids as Transparent Electrodes in Regular and Inverted Organic Solar Cell Structures  

E-print Network

An approach is presented to modify the WF of solution-processed sol-gel derived ZnOover an exceptionally wide range of more than 2.3 eV. This approach relies on the formation of dense and homogeneous self-assembled monolayers based on phosphonic acids with different dipole moments. This allows us to apply ZnO as charge selective bottom electrodes in either regular or inverted solar cell structures, using P3HT:PCBM as the active layer. These devices compete with or even exceed the performance of the reference cell on ITO/PEDOT:PSS. Our finding challenges the current view that bottom electrodes in inverted solar cells need to be electron-blocking for good device performance.

Ilja Lange; Sina Reiter; Juliane Kniepert; Fortunato Piersimoni; Michael Paetzel; Jana Hildebrandt; Thomas Brenner; Stefan Hecht; Dieter Neher

2015-02-05

130

Zinc  

MedlinePLUS

... they may not get enough zinc. People with sickle cell disease because they might need more zinc. ... Children in developing countries often die from diarrhea. Studies show that zinc dietary supplements help reduce the ...

131

Preparation of n-ZnO/ p-Si solar cells by oxidation of zinc nanoparticles: effect of oxidation temperature on the photovoltaic properties  

NASA Astrophysics Data System (ADS)

In this study, n-ZnO/ p-Si solar cells were fabricated by spraying ZnO nanoparticles (NPs) film synthesised by dissolving of high purity zinc in hydrogen peroxide H2O2 followed by thermal oxidation in air on p-type silicon substrates. The oxidation was carried out at different temperatures (200-500) C. The crystalline structure of the ZnO NPs films was investigated by X-ray diffraction which indicated wurtzite structure films along (100) plane. The morphology of the NPs was studied by atomic force microscopy and scanning electron microscopy. The result showed an average grain size of ZnO NPs in the range of (72.7-95.8) nm and the surface roughness increasing with oxidation temperature. Three peaks located at ultraviolet, violet and green emission regions were noticed in the photoluminescence spectra of ZnO NPs. From optical studies, it was shown that the direct optical band gap is found to be in the range of (3.85-3.96) eV depended on the oxidation temperature. The synthesised ZnO films have n-type conductivity, and the mobility was in the range of (7-24) cm2 V-1 s-1. Current-voltage I- V and capacitance-voltage C- V of ZnO NPs/Si heterojunction solar cell were investigated as function of oxidation temperature. The spectral response of n-ZnO NPs/ p-Si solar cell showed two peaks of response and its maximum value approaching 0.62 mA W-1 at ? = 800 nm. Solar cell oxidized at 500 C gave open circuit voltage V OC of 375 mV, short circuit current density J SC of 25 mA cm-2, a fill factor FF of 0.72, and conversion efficiency ? of 6.79 % under illumination of 100 mW cm-2.

Ismail, Raid A.; Al-Jawad, Selma M. H.; Hussein, Naba

2014-12-01

132

Wurtzite copper-zinc-tin sulfide as a superior counter electrode material for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Wurtzite and kesterite Cu2ZnSnS4 (CZTS) nanocrystals were employed as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). Compared to kesterite CZTS, the wurtzite CZTS exhibited higher electrocatalytic activity for catalyzing reduction of iodide electrolyte and better conductivity. Accordingly, the DSSC with wurtzite CZTS CE generated higher power conversion efficiency (6.89%) than that of Pt (6.23%) and kesterite CZTS (4.89%) CEs.

Kong, Jun; Zhou, Zheng-Ji; Li, Mei; Zhou, Wen-Hui; Yuan, Sheng-Jie; Yao, Rong-Yue; Zhao, Yang; Wu, Si-Xin

2013-11-01

133

Wurtzite copper-zinc-tin sulfide as a superior counter electrode material for dye-sensitized solar cells  

PubMed Central

Wurtzite and kesterite Cu2ZnSnS4 (CZTS) nanocrystals were employed as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). Compared to kesterite CZTS, the wurtzite CZTS exhibited higher electrocatalytic activity for catalyzing reduction of iodide electrolyte and better conductivity. Accordingly, the DSSC with wurtzite CZTS CE generated higher power conversion efficiency (6.89%) than that of Pt (6.23%) and kesterite CZTS (4.89%) CEs. PMID:24191954

2013-01-01

134

Comparative modeling of InP solar cell structures  

NASA Technical Reports Server (NTRS)

The comparative modeling of p(+)n and n(+)p indium phosphide solar cell structures is studied using a numerical program PC-1D. The optimal design study has predicted that the p(+)n structure offers improved cell efficiencies as compared to n(+)p structure, due to higher open-circuit voltage. The various cell material and process parameters to achieve the maximum cell efficiencies are reported. The effect of some of the cell parameters on InP cell I-V characteristics was studied. The available radiation resistance data on n(+)p and p(+)p InP solar cells are also critically discussed.

Jain, R. K.; Weinberg, I.; Flood, D. J.

1991-01-01

135

Automatically activated, 300 ampere-hour silver-zinc cell  

NASA Technical Reports Server (NTRS)

A prototype silver zinc cell is reported for which the electrolyte is being stored in a separate tank; the cell is being activated when additional power is required by collapsing the neoprene bellows container and thus forcing the electrolyte into cell through a plastic connection. A solar array is proposed as main power source for the flow actuator.

Hennigan, T. J.

1972-01-01

136

Efficient indium-tin-oxide free inverted organic solar cells based on aluminum-doped zinc oxide cathode and low-temperature aqueous solution processed zinc oxide electron extraction layer  

SciTech Connect

Indium-tin-oxide (ITO) free inverted organic solar cells (IOSCs) based on aluminum-doped zinc oxide (AZO) cathode, low-temperature aqueous solution processed zinc oxide (ZnO) electron extraction layer, and poly(3-hexylthiophene-2, 5-diyl):[6, 6]-phenyl C{sub 61} butyric acid methyl ester blend were realized in this work. The resulted IOSC with ZnO annealed at 150?C shows the superior power conversion efficiency (PCE) of 3.01%, if decreasing the ZnO annealing temperature to 100?C, the obtained IOSC also shows a PCE of 2.76%, and no light soaking issue is observed. It is found that this ZnO film not only acts as an effective buffer layer but also slightly improves the optical transmittance of AZO substrates. Further, despite the relatively inferior air-stability, these un-encapsulated AZO/ZnO IOSCs show comparable PCEs to the referenced ITO/ZnO IOSCs, which demonstrates that the AZO cathode is a potential alternative to ITO in IOSCs. Meanwhile, this simple ZnO process is compatible with large area deposition and plastic substrates, and is promising to be widely used in IOSCs and other relative fields.

Chen, Dazheng; Zhang, Chunfu, E-mail: cfzhang@xidian.edu.cn; Wang, Zhizhe; Zhang, Jincheng; Tang, Shi; Wei, Wei; Sun, Li; Hao, Yue, E-mail: yhao@xidian.edu.cn [State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, School of Microelectronics, Xidian University, No. 2 South Taibai Road, Xi'an 710071 (China)

2014-06-16

137

Efficient indium-tin-oxide free inverted organic solar cells based on aluminum-doped zinc oxide cathode and low-temperature aqueous solution processed zinc oxide electron extraction layer  

NASA Astrophysics Data System (ADS)

Indium-tin-oxide (ITO) free inverted organic solar cells (IOSCs) based on aluminum-doped zinc oxide (AZO) cathode, low-temperature aqueous solution processed zinc oxide (ZnO) electron extraction layer, and poly(3-hexylthiophene-2, 5-diyl):[6, 6]-phenyl C61 butyric acid methyl ester blend were realized in this work. The resulted IOSC with ZnO annealed at 150 C shows the superior power conversion efficiency (PCE) of 3.01%, if decreasing the ZnO annealing temperature to 100 C, the obtained IOSC also shows a PCE of 2.76%, and no light soaking issue is observed. It is found that this ZnO film not only acts as an effective buffer layer but also slightly improves the optical transmittance of AZO substrates. Further, despite the relatively inferior air-stability, these un-encapsulated AZO/ZnO IOSCs show comparable PCEs to the referenced ITO/ZnO IOSCs, which demonstrates that the AZO cathode is a potential alternative to ITO in IOSCs. Meanwhile, this simple ZnO process is compatible with large area deposition and plastic substrates, and is promising to be widely used in IOSCs and other relative fields.

Chen, Dazheng; Zhang, Chunfu; Wang, Zhizhe; Zhang, Jincheng; Tang, Shi; Wei, Wei; Sun, Li; Hao, Yue

2014-06-01

138

Inverted polymer solar cells with sol-gel derived cesium-doped zinc oxide thin film as a buffer layer  

NASA Astrophysics Data System (ADS)

An inverted structure of polymer solar cells based on Poly(3-hexylthiophene)(P3HT):[6-6] Phenyl-(6) butyric acid methyl ester (PCBM) with thin films of sol-gel derived Cesium doped ZnO (Cs:ZnO) was developed as an efficient cathode buffer layer. Doped and undoped thin films were deposited using a less studied method, doctor blade, which was compatible with Roll-2-Roll printing method. By comparing the effect of Cs:ZnO thin films with various dopant ratio on the performance of inverted polymer solar cells, 0.5% Cs doped ZnO was found as the most effective doping level among the selected doping ratios. Using 30 nm thickness of 0.5% Csn:ZnO thin film as an electron transport layer led to the average efficiency which was significantly higher than (9%) that of similar devices employing the same thickness of undoped ZnO film. Results showed that the devices fabricated with 1% and 2% cesium doped ZnO yielded lower power conversion efficiency, which could be due to the lower FF. Also, the influence of dopant incorporation on the optical transmittance and electrical conductivity of ZnO films was investigated.

Ahmadi, Mehdi; Mirabbaszadeh, Kavoos; Salari, Saeid; Fatehy, Hamed

2014-09-01

139

Nanowire-based hierarchical tin oxide/zinc stannate hollow microspheres: Enhanced solar energy utilization efficiency for dye-sensitized solar cells and photocatalytic degradation of dyes  

NASA Astrophysics Data System (ADS)

Nanowire-based SnO2/Zn2SnO4 hollow microspheres are synthesized using a facile one-pot method for solar energy conversion and environment cleaning. The micrometer-sized hollow spheres possess a hierarchical structure with the shell consisting of nanowires. With the hybrid SnO2/Zn2SnO4 microspheres as photoanodes, the dye-sensitized solar cells (DSSCs) with an overall 4.72% photoconversion efficiency is obtained, nearly 240% improvement over the DSSCs that uses nanorod-based hierarchical SnO2 microspheres. The hybrid microspheres are also determined to be high-performance photocatalyst with a better recyclability for the photodegradation of dyes under simulated sunlight irradiation. These improvements of solar energy utilization are ascribed to the formation of the heterojunctions between SnO2 and Zn2SnO4 to enhance electron transport and charge-separation efficiencies.

Li, Zhengdao; Zhou, Yong; Mao, Wutao; Zou, Zhigang

2015-01-01

140

Solar cells  

NASA Astrophysics Data System (ADS)

The history, state of the art, and future prospects of solar cells are reviewed. Solar cells are already competitive in a wide range of low-power applications, and during the 1980's they are expected to become cheaper to run than diesel or gasoline generators, the present mainstay of isolated communities. At this stage they will become attractive for water pumping, irrigation, and rural electrification, particularly in developing countries. With further cost reduction, they may be used to augment grid supplies in domestic, commercial, institutional, and industrial premises. Cost reduction to the stage where photovoltaics becomes economic for large-scale power generation in central stations depends on a technological breakthrough in the development of thin-film cells. DOE aims to reach this goal by 1990, so that by the end of the century about 20% of the estimated annual additions to their electrical generating capacity will be photovoltaic.

Treble, F. C.

1980-11-01

141

Selected High Pressure Studies: Aluminum, Arsenic, Boron Arsenide, Aluminum Arsenide, Aluminum Phosphide, Zinc Selenide, Aluminum Antimonide, Diaspore, and Hydrogen - Composites.  

NASA Astrophysics Data System (ADS)

The crystal structures of Al, As, BAs, AlAs, AlP, ZnSe, AlSb, and AlOOH have been studied with energy dispersive x-ray diffraction to very high static pressures generated by diamond anvil cell technology at room temperature. The static equation of state of Al has been measured to 220 GPa, corresponding to a compression of V/V _0 = 0.50. No phase transformation from the fcc to hcp phase was observed. The equation of state fits the H11 form for a simple solid with no free parameters. The phase sequence on compression of As was: alpha to scto As(III)to bcc. As(III) may have the alpha-Np structure. The equilibrium transformation pressures, P_ {e}, between sc/As(III) and As(III)/bcc are 48 +/- 11 and 97 +/- 14 GPa, respectively. A transformation from the zinc blende to an amorphous crystal structure was observed at 125 GPa in BAs. This is the first evidence that pressure induced amorphization in AB compounds is a kinetically frustrated process. AlAs and AlP were found to undergo first order phase transformations from the zinc blende to NiAs structure with volume changes of 17% at 7 +/- 5, and 9.5 +/- 5 GPa, respectively. The NiAs phase of AlP was found to exhibit metallic type reflectivity in the near infra-red. The rock salt phase of ZnSe transformed to a simple hexagonal type structure at 55 +/- 8 GPa and was observed up to 120 GPa. The beta -Sn phase of AlSb started to transform to an unknown structure at 43 GPa. The equation of state of diaspore was measured to 65 GPa. Effective medium theory has been applied to an idealized model of a ceramic powder in a solidified gas and found to produce dispersion in the reflectance spectrum for wavelengths greater than the particle size. Ruby powder with a particle size of approximately {1over 2}mum in hydrogen is shown to give dispersion in the infrared reflectance spectrum that resembles a plasma edge.

Greene, Raymond G.

1995-01-01

142

Nanorod-nanosheet hierarchically structured ZnO crystals on zinc foil as flexible photoanodes for dye-sensitized solar cells.  

PubMed

In this paper, ZnO nanorod-nanosheet hierarchical structures were fabricated using a facile method on zinc foil and used as flexible photoanodes in dye-sensitized solar cells (DSCs). Compared to nanorods (NRs) obtained by the dissolution-precipitation method, the nanorod-nanosheet (NR-NS) hierarchical structures obtained by a second-step homogeneous precipitation improved the performance of DSCs by increasing photocurrent density significantly. As a result, the power conversion efficiency of the devices based on such a NR-NS hierarchical structure reached up to 2.4% under 100 mW cm(-2) illumination condition. This represents an enhancement by 108% as compared to DSCs based on NR assembled nanoflowers, for which the efficiency was 1.1%. The enhancement of the photocurrent was due mainly to the much larger specific surface area and resulting dye-loading amount. The electron transport properties in this structure were also investigated by means of electrochemical impedance spectroscopy (EIS). Furthermore, the formation mechanism of the NR-NS hierarchical structures are discussed. PMID:23353672

Gao, Rui; Tian, Jianjun; Liang, Zhiqiang; Zhang, Qifeng; Wang, Liduo; Cao, Guozhong

2013-03-01

143

Highly conductive and transparent reduced graphene oxide/aluminium doped zinc oxide nanocomposite for the next generation solar cell applications  

NASA Astrophysics Data System (ADS)

In this paper, aluminum-doped zinc oxide(AZO)/reduced graphene oxide nano-composite thin films are synthesized by a one-pot, solution-processed method. The nanocomposite film has been extensively characterized using scanning electron microscopy (SEM), X-ray-diffraction (XRD), energy dispersive spectroscopy (EDS), Hall effect measurement and UV-Vis spectroscopy. It is found that the controlled addition of reduced graphene oxide into AZO can lower the film's resistivity without causing significant degradation of optical transparency. In addition, nanocomposite films post-annealed at process temperature at 500 C possesses the lowest resistivity and the highest optical transmittance and that further increases in the annealing temperature degrades the film's property due to nucleation of other phases of the AZO.

Bu, Ian Y. Y.

2013-12-01

144

Photovoltaic solar cells: An overview of state-of-the-art cell development and environmental issues  

Microsoft Academic Search

This paper gives an overview of the materials and methods used for fabricating photovoltaic solar cell devices. The technologies discussed include those based on the use of silicon (in the crystalline, multicrystalline, amorphous and micro-crystalline forms), the IIIV compounds (e.g. gallium arsenide, indium phosphide and gallium antimonide), the polycrystalline compounds (e.g. cadmium telluride, copper gallium indium diselenide and copper indium

R. W. Miles; K. M. Hynes; I. Forbes

2005-01-01

145

The influence of atmospheric species on the degradation of aluminum doped zinc oxide and Cu(In,Ga)Se2 solar cells  

NASA Astrophysics Data System (ADS)

Aluminum doped zinc oxide (ZnO:Al) layers were exposed to the atmospheric gases carbondioxide (CO2), oxygen (O2), nitrogen (N2) and air as well as liquid H2O purged with these gases, in order to investigate the chemical degradation behavior of these layers. The samples were analyzed by electrical, compositional and optical measurements before, during and after exposure to these conditions in order to follow the degradation behavior of these layers in time. We have shown that ZnO:Al layers degraded in the presence of a mixture of H2O and CO2. Individually, CO2 does not impact the degradation at all during the tested period, while the individual impact of H2O is small. However, when CO2 is also present, the concentration of OH increases greatly in the bulk and even more at the air/ZnO:Al and the ZnO:Al/glass interfaces. Carbon based species are then also present, indicating that Zn5(OH)6(CO3)2 is also formed at the grain boundaries. The degradation of ZnO:Al was accompanied by the occurrence of holes in the ZnO:Al layer near the ZnO:Al/glass interface. The impact of gaseous O2 as well as water purged with N2 and O2 on ZnO:Al degradation is very small. Complete Cu(In,Ga)Se2 solar cells were also exposed to unpurged liquid H2O and H2O purged with CO2, O2, N2 and air. The samples exposed to H2O purged with air and CO2 showed a rapid decrease in efficiency after approximately 180 hours of exposure. This efficiency decrease is mainly driven by a very rapid decrease in current density and an increase in series resistance.

Theelen, Mirjam; Foster, Christopher; Dasgupta, Supratik; Vroon, Zeger; Barreau, Nicolas; Zeman, Miro

2014-10-01

146

Aluminium phosphide-induced leukopenia.  

PubMed

Acute intoxication from the pesticide aluminium phosphide is a relatively rare, life-threatening condition in which cardiovascular decompensation is the most feared problem. We report the case of a patient exposed to aluminium phosphide-liberated phosphine gas. It resulted in the development of a gastroenteritis-like syndrome accompanied by severe reduction in white blood cell numbers as an early and prominent manifestation. By affecting important physiological processes such as mitochondrial function and reactive oxygen species homeostasis, phosphine could cause severe toxicity. After presenting the characteristics of certain leucocyte subpopulations we provide the current molecular understanding of the observed leukopenia which in part seems paradoxical. PMID:24172776

Ntelios, Dimitrios; Mandros, Charalampos; Potolidis, Evangelos; Fanourgiakis, Panagiotis

2013-01-01

147

DIRECT SOLAR THERMAL DISSOCIATION OF ZINC OXIDE: CONDENSATION AND CRYSTALLISATION OF ZINC IN THE PRESENCE OF OXYGEN  

Microsoft Academic Search

The solar thermal production of zinc from zinc oxide is part of a two-step water splitting cycle. Zinc oxide thermally dissociates into zinc vapour and oxygen at elevated temperatures;ZnO(s)=Zn(g)+0.5O2In practice, the yield of zinc depends on the kinetics of dissociation and the technical feasibility of quenching its gaseous products fast enough to avoid reoxidation. As the gaseous products cool, the

A. WEIDENKAFF; A. STEINFELD; A. WOKAUN; P. O. AUER; B. EICHLER; A. RELLER

1999-01-01

148

GaAsP on GaP top solar cells  

NASA Technical Reports Server (NTRS)

GaAsP on GaP top solar cells as an attachment to silicon bottom solar cells are being developed. The GaAsP on GaP system offers several advantages for this top solar cell. The most important is that the gallium phosphide substrate provides a rugged, transparent mechanical substrate which does not have to be removed or thinned during processing. Additional advantages are that: (1) gallium phosphide is more oxidation resistant than the III-V aluminum compounds, (2) a range of energy band gaps higher than 1.75 eV is readily available for system efficiency optimization, (3) reliable ohmic contact technology is available from the light-emitting diode industry, and (4) the system readily lends itself to graded band gap structures for additional increases in efficiency.

Mcneely, J. B.; Negley, G. H.; Barnett, A. M.

1985-01-01

149

Hybrid a-Si/nc-Si solar cells fabricated on a directly-deposited textured zinc oxide transparent conductor  

NASA Astrophysics Data System (ADS)

This paper reports the development of a VHF PECVD process at 40.68 MHz for deposition of device-grade nc-Si:H. It further reports the evaluation of textured ZnO:Al films produced by hollow cathode sputtering as regards their suitability to serve as a TCO substrate for a-Si:H / nc-Si:H tandem device fabrication. The tandem devices were produced using an established VHF PECVD process at 100 MHz. Both VHF processes are capable of producing similar nc-Si:H material based on their analysis using micro-Raman spectroscopy. For the tandem junction devices, a peak in device efficiency was obtained at a Raman crystalline fraction of 50-52 % and a microstructure parameter of 0.60-0.68. A best tandem cell efficiency of 9.9% was achieved on HC ZnO compared to 11.3% on a reference Type-U SnO2 substrate.

Delahoy, Alan E.; Liu, Tongyu; Saraf, Gaurav; Patel, Anamika; Cambridge, John; Guo, Sheyu; Delli Veneri, Paola; Mercaldo, Lucia V.; Usatii, Iurie

2009-08-01

150

Cell Calcium 40 (2006) 393402 Determining zinc with commonly used calcium and zinc fluorescent  

E-print Network

Cell Calcium 40 (2006) 393­402 Determining zinc with commonly used calcium and zinc fluorescent rights reserved. Keywords: Zinc; Calcium; Fluorescence; Fluorophore; Calcium Green-1; Fura-2; Fluo-3 Zn2+ and histo- chemically reactive free Zn2+ (chelatable Zn2+). Bound zinc, which makes up

Li, Yang V.

151

Solution-processed zinc oxide/polyethylenimine nanocomposites as tunable electron transport layers for highly efficient bulk heterojunction polymer solar cells.  

PubMed

In this study, we employed polyethylenimine-doped sol-gel-processed zinc oxide composites (ZnO:PEI) as efficient electron transport layers (ETL) for facilitating electron extraction in inverted polymer solar cells. Using ultraviolet photoelectron spectroscopy, synchrotron grazing-incidence small-angle X-ray scattering and transmission electron microscopy, we observed that ZnO:PEI composite films' energy bands could be tuned considerably by varying the content of PEI up to 7 wt %-the conduction band ranged from 4.32 to 4.0 eV-and the structural order of ZnO in the ZnO:PEI thin films would be enhanced to align perpendicular to the ITO electrode, particularly at 7 wt % PEI, facilitating electron transport vertically. We then prepared two types of bulk heterojunction systems-based on poly(3-hexylthiophene) (P3HT):phenyl-C61-butryric acid methyl ester (PC61BM) and benzo[1,2-b:4,5-b?]dithiophene-thiophene-2,1,3-benzooxadiazole (PBDTTBO):phenyl-C71-butryric acid methyl ester (PC71BM)-that incorporated the ZnO:PEI composite layers. When using a composite of ZnO:PEI (93:7, w/w) as the ETL, the power conversion efficiency (PCE) of the P3HT:PC61BM (1:1, w/w) device improved to 4.6% from a value of 3.7% for the corresponding device that incorporated pristine ZnO as the ETL-a relative increase of 24%. For the PBDTTBO:PC71BM (1:2, w/w) device featuring the same amount of PEI blended in the ETL, the PCE improved to 8.7% from a value of 7.3% for the corresponding device that featured pure ZnO as its ETL-a relative increase of 20%. Accordingly, ZnO:PEI composites can be effective ETLs within organic photovoltaics. PMID:25697544

Chen, Hsiu-Cheng; Lin, Shu-Wei; Jiang, Jian-Ming; Su, Yu-Wei; Wei, Kung-Hwa

2015-03-25

152

Effects of zinc supplementation and zinc chelation on in vitro ?-cell function in INS-1E cells  

PubMed Central

Background Zinc is essential for the activities of pancreatic ?-cells, especially insulin storage and secretion. Insulin secretion leads to co-release of zinc which contributes to the paracrine communication in the pancreatic islets. Zinc-transporting proteins (zinc-regulated transporter, iron-regulated transporter-like proteins [ZIPs] and zinc transporters [ZnTs]) and metal-buffering proteins (metallothioneins, MTs) tightly regulate intracellular zinc homeostasis. The present study investigated how modulation of cellular zinc availability affects ?-cell function using INS-1E cells. Results Using INS-1E cells, we found that zinc supplementation and zinc chelation had significant effects on insulin content and insulin secretion. Supplemental zinc within the physiological concentration range induced insulin secretion. Insulin content was reduced by zinc chelation with N,N,N,N-tektrakis(2-pyridylmethyl)-ethylenediamine. The changes in intracellular insulin content following exposure to various concentrations of zinc were reflected by changes in the expression patterns of MT-1A, ZnT-8, ZnT-5, and ZnT-3. Furthermore, high zinc concentrations induced cell necrosis while zinc chelation induced apoptosis. Finally, cell proliferation was sensitive to changes in zinc the concentration. Conclusion These results indicate that the ?-cell-like function and survival of INS-1E cells are dependent on the surrounding zinc concentrations. Our results suggest that regulation of zinc homeostasis could represent a pharmacological target. PMID:24502363

2014-01-01

153

Effect of resveratrol and zinc on intracellular zinc status in normal human prostate epithelial cells  

Technology Transfer Automated Retrieval System (TEKTRAN)

To evaluate the influence of resveratrol on cellular zinc status, normal human prostate epithelial (NHPrE) cells were treated with 6 levels of resveratrol (0, 0.5, 1, 2.5, 5 and 10 microM) and 4 levels of zinc [0, 4, 16, and 32 microM for zinc-deficient (ZD), zinc-normal (ZN), zinc-adequate (ZA), an...

154

Transparent electrode materials for solar cells  

Microsoft Academic Search

Alternatives for replacing the expensive ITO are explored and Poly(ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS) is introduced as one possibility. We present the first small-molecule organic solar cells employing only PEDOT:PSS as transparent electrode. Solar cells on glass and on flexible plastic foil were prepared, using a p-doped hole transporting material, zinc phthalocyanine (ZnPc) and C60 as donor-acceptor heterojunction, and an exciton

Jan Meiss; Christian L. Uhrich; Karsten Fehse; Steffen Pfuetzner; Moritz K. Riede; Karl Leo

2008-01-01

155

The production of zinc by thermal dissociation of zinc oxidesolar chemical reactor design  

Microsoft Academic Search

We describe the design, fabrication, and preliminary test of a novel solar chemical reactor for conducting the thermal dissociation of ZnO into zinc and oxygen at above 2000 K. The reactor configuration features a windowed rotating cavity-receiver lined with ZnO particles that are held by centrifugal force. With this arrangement, ZnO is directly exposed to high-flux solar irradiation and serves

P. Haueter; S. Moeller; R. Palumbo; A. Steinfeld

1999-01-01

156

Solar Photovoltaic Cells.  

ERIC Educational Resources Information Center

Reviews information on solar radiation as an energy source. Discusses these topics: the key photovoltaic material; the bank theory of solids; conductors, semiconductors, and insulators; impurity semiconductors; solid-state photovoltaic cell operation; limitations on solar cell efficiency; silicon solar cells; cadmium sulfide/copper (I) sulfide

Mickey, Charles D.

1981-01-01

157

Effects of growth temperature and device structure on GaP solar cells grown by molecular beam epitaxy  

NASA Astrophysics Data System (ADS)

Gallium phosphide (GaP) is an attractive candidate for wide-bandgap solar cell applications, possessing the largest bandgap of the III-arsenide/phosphides without aluminum. However, GaP cells to date have exhibited poor internal quantum efficiency (IQE), even for photons absorbed by direct transitions, motivating improvements in material quality and device structure. In this work, we investigated GaP solar cells grown by molecular beam epitaxy over a range of substrate temperatures, employing a much thinner emitter than in prior work. Higher growth temperatures yielded the best solar cell characteristics, indicative of increased diffusion lengths. Furthermore, the inclusion of an AlGaP window layer improved both open-circuit voltage and short wavelength IQE.

Vaisman, M.; Tomasulo, S.; Masuda, T.; Lang, J. R.; Faucher, J.; Lee, M. L.

2015-02-01

158

Nanocoax Solar Cells  

Microsoft Academic Search

A novel architecture for high efficiency solar energy conversion, employing separated photo-- and --voltaic pathways and antenna-based light collection, is described. This material-independent architecture solves the ``thick-and-thin'' conundrum of solar photovoltaics, wherein solar cells must be thick enough to absorb light yet thin enough to allow for charge extraction. Our solar cells are comprised of arrays of high aspect ratio,

M. J. Naughton; K. Kempa; Z. F. Ren; J. Rybczynski; T. Paudel; Y. Gao; Y. Xu

2008-01-01

159

3. Right side of Zinc Plant, from Cell Room midpoint ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. Right side of Zinc Plant, from Cell Room midpoint to Plant Office (foreground) and #5 Roaster and Concentrate Handling (background). View is to the east. - Sullivan Electrolytic Zinc Plant, Government Gulch, Kellogg, Shoshone County, ID

160

Solar cell device  

SciTech Connect

A solar cell array is equipped with serially or parallel connected reverse polarity diodes formed simultaneously with the array. The diodes are constituted by one or more solar cells of the array which may be shaded to prevent photoelectric conversion, and which are electrically connected in reverse polarity with respect to the remaining cells.

Nishiura, M.; Haruki, H.; Miyagi, M.; Sakai, H.; Uchida, Y.

1984-06-26

161

Solar cell encapsulation  

NASA Technical Reports Server (NTRS)

A polymer syrup for encapsulating solar cell assemblies. The syrup includes uncrosslinked poly(n-butyl)acrylate dissolved in n-butyl acrylate monomer. Preparation of the poly(n-butyl)acrylate and preparation of the polymer syrup is disclosed. Methods for applying the polymer syrup to solar cell assemblies as an encapsulating pottant are described. Also included is a method for solar cell construction utilizing the polymer syrup as a dual purpose adhesive and encapsulating material.

Gupta, Amitava (Inventor); Ingham, John D. (Inventor); Yavrouian, Andre H. (Inventor)

1983-01-01

162

Heterojunction solar cell  

DOEpatents

A high-efficiency single heterojunction solar cell is described wherein a thin emitter layer (preferably Ga[sub 0.52]In[sub 0.48]P) forms a heterojunction with a GaAs absorber layer. The conversion efficiency of the solar cell is at least 25.7%. The solar cell preferably includes a passivating layer between the substrate and the absorber layer. An anti-reflection coating is preferably disposed over the emitter layer. 1 fig.

Olson, J.M.

1994-08-30

163

Morphology control of zinc regeneration for zinc-air fuel cell and battery  

NASA Astrophysics Data System (ADS)

Morphology control is crucial both for zinc-air batteries and for zinc-air fuel cells during zinc regeneration. Zinc dendrite should be avoided in zinc-air batteries and zinc pellets are yearned to be formed for zinc-air fuel cells. This paper is mainly to analyze the mechanism of shape change and to control the zinc morphology during charge. A numerical three-dimensional model for zinc regeneration is established with COMSOL software on the basis of ionic transport theory and electrode reaction electrochemistry, and some experiments of zinc regeneration are carried out. The deposition process is qualitatively analyzed by the kinetics Monte Carlo method to study the morphological change from the electrocrystallization point of view. Morphological evolution of deposited zinc under different conditions of direct currents and pulse currents is also investigated by simulation. The simulation shows that parametric variables of the flowing electrolyte, the surface roughness and the structure of the electrode, the charging current and mode affect morphological evolution. The uniform morphology of deposited zinc is attained at low current, pulsating current or hydrodynamic electrolyte, and granular morphology is obtained by means of an electrode of discrete columnar structure in combination with high current and flowing electrolyte.

Wang, Keliang; Pei, Pucheng; Ma, Ze; Xu, Huachi; Li, Pengcheng; Wang, Xizhong

2014-12-01

164

Fundamentals of solar cells  

Microsoft Academic Search

This text is addressed to upper level graduate students with background in solid state physics and to scientists and engineers involved in solar cell research. The author aims to present fundamental physical principles rather than the state-of-the-art. Specific devices are used to illustrate basic phenomena and to indicate possibilities for innovative design. Contents, abridged: Solar insolation. The calculation of solar

A. L. Farhenbruch; R. H. Bube

1983-01-01

165

Solar cell shingle  

NASA Technical Reports Server (NTRS)

A solar cell shingle was made of an array of solar cells on a lower portion of a substantially rectangular shingle substrate made of fiberglass cloth or the like. The solar cells may be encapsulated in flourinated ethylene propylene or some other weatherproof translucent or transparent encapsulant to form a combined electrical module and a roof shingle. The interconnected solar cells were connected to connectors at the edge of the substrate through a connection to a common electrical bus or busses. An overlap area was arranged to receive the overlap of a cooperating similar shingle so that the cell portion of the cooperating shingle may overlie the overlap area of the roof shingle. Accordingly, the same shingle serves the double function of an ordinary roof shingle which may be applied in the usual way and an array of cooperating solar cells from which electrical energy may be collected.

Forestieri, A. F.; Ratajczak, A. F.; Sidorak, L. G. (inventors)

1977-01-01

166

Solar cells for solar power satellites  

Microsoft Academic Search

The concept of a solar-cell array for a solar power satellite is developed to permit evaluation of its economic feasibility for generating power for delivery to public utilities on earth. Gallium arsenide solar cells were considered but it could not be assured that the world gallium resources could support constructions of two solar power satellites per year. Therefore, for preliminary

H. Oman

1978-01-01

167

High efficiency cadmium telluride and zinc telluride based thin-film solar cells. Annual subcontract report, 1 March 1990--28 February 1992  

SciTech Connect

This report describes work to improve the basic understanding of CdTe and ZnTe alloys by growing and characterizing these films along with cell fabrication. The major objective was to develop wide-band-gap (1.6--1.8 eV) material for the top cell, along with compatible window material and transparent ohmic contacts, so that a cascade cell design can be optimized. Front-wall solar cells were fabricated with a glass/SnO{sub 2}/CdS window, where the CdS film is thin to maximize transmission and current. Wide-band-gap absorber films (E{sub g} = 1.75 eV) were grown by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD) techniques, which provided excellent control for tailoring the film composition and properties. CdZnTe films were grown by both MBE and MOCVD. All the as-grown films were characterized by several techniques (surface photovoltage spectroscopy, Auger electron spectroscopy (AES), and x-ray photoelectron spectroscopy (XPS)) for composition, bulk uniformity, thickness, and film and interface quality. Front-wall-type solar cells were fabricated in collaboration with Ametek Materials Research Laboratory using CdTe and CdZnTe polycrystalline absorber films. The effects of processing on ternary film were studied by AES and XPS coupled with capacitance voltage and current voltage measurements as a function of temperature. Bias-dependent spectral response and electrical measurements were used to test some models in order to identify and quantify dominant loss mechanisms.

Rohatgi, A.; Sudharsanan, R.; Ringel, S.A.; Chou, H.C. [Georgia Inst. of Tech., Atlanta, GA (United States)

1992-10-01

168

Optimization of dye-sensitized solar cells using thin film zinc oxide and titanium dioxide semiconducting materials fabricated by electrophoretic deposition  

NASA Astrophysics Data System (ADS)

The Dye-Sensitized Solar Cell (DSC) has been touted to be one of the more promising photovoltaic solar cells for capturing solar energy and its conversion to electricity. DSCs have advantages of cost and ease of construction but disadvantages with respect to low conversion efficiencies and system stability. To improve upon the efficiency of DSCs, many studies regarding materials related to the components of these cells such as the photoelectrode, the type of dye, the electrolyte, and cell characteristics have been conducted. As such and efficiencies in some cases have reached levels of 11 % thus far. However, it is generally thought that this number can be improved and that the optimal materials and methods of cell construction have yet to be established. It is generally thought that problems restricting improvements in DSC performance fall into the following categories: (1) An optimum choice of the photoelectrode (PE) material; (2) Transport of electrons to the conductive substrate (collector); (3) Injection of electrons from dye to PE; (4) Redox reactions of electrolyte; (5) A general lack of considering the entire cell system as opposed to single components. In this thesis, we investigated the effects of the following factors to solve some of the perceived problems: (1) PE material; (2) Morphology of the PE; (3) Thickness of PE film; (4) Amount of dye on the PE films as a function of the factors (1--3); (5) Optimal conditions for DSC. As PE materials, we selected ZnO and TiO2 due to their material characteristics and promising results from previous studies. ZnO nanorods were synthesized via a solvothermal method using a ZnO sol and subsequently characterized. DSCs with PE films of ZnO nanorods and commercially available ZnO nanopowders were constructed using electrophoretic deposition method and effects of film morphology, film thickness and the amount of dye loading studied. Similarly, DSCs with films of TiO2 and ZnO nanopowders were also constructed and the same effects investigated. We would hope that these findings would prove useful for those wishing to further optimize DSCs for higher efficiencies.

Hara, Yukihiro

2011-12-01

169

Heterostructure solar cells  

NASA Technical Reports Server (NTRS)

The performance of gallium arsenide solar cells grown on Ge substrates is discussed. In some cases the substrate was thinned to reduce overall cell weight with good ruggedness. The conversion efficiency of 2 by 2 cm cells under AMO reached 17.1 percent with a cell thickness of 6 mils. The work described forms the basis for future cascade cell structures, where similar interconnecting problems between the top cell and the bottom cell must be solved. Applications of the GaAs/Ge solar cell in space and the expected payoffs are discussed.

Chang, K. I.; Yeh, Y. C. M.; Iles, P. A.; Morris, R. K.

1987-01-01

170

Zinc and its transporters, pancreatic ?-cells, and insulin metabolism.  

PubMed

Zinc is an essential trace metal for life. Two families of zinc transporters, SLC30A (ZNT) and SLC39A (ZIP) are required for maintaining cellular zinc homeostasis. ZNTs function to decrease cytoplasmic zinc concentrations whereas ZIPs do the opposite. Expression of zinc transporters can be tissue/cell-type specific or ubiquitous. Zinc transporters that are limited in tissue/cell distributions usually perform specialized tasks to satisfy biological processes in a given cell. For example, ZNT8 is mainly expressed in ?-cells and functions to deliver zinc into granules for insulin maturation and secretion. Many other zinc transporters are also expressed in ?-cells. Defects in these zinc transporters have been associated with abnormalities in insulin synthesis, maturation, and secretion and subsequent glucose metabolism. This review focuses on the specific roles of zinc and its transporters in insulin metabolism and describes the current knowledge of the function of zinc transporters in ?-cell health in animal knockout mouse models with respect to diabetes development in humans. PMID:24559925

Huang, Liping

2014-01-01

171

High-efficiency cadmium and zinc-telluride-based thin-film solar cells. Annual subcontract report, 1 March 1990--28 February 1991  

SciTech Connect

This report describes research into polycrystalline CdTe solar cells grown by metal-organic chemical vapor deposition. Efficiencies of {approximately}10% were achieved using both p-i-n and p-n structures. A pre-heat treatment of CdS/SnO{sub 2}/glass substrates at 450{degrees}C in hydrogen atmosphere prior to the CdTe growth was found to be essential for high performance because this heat treatment reduces oxygen-related defects from the CdS surface. However, this treatment also resulted in a Cd-deficient CdS surface, which may in part limit the CdTe cell efficiency to 10% due to Cd vacancy-related interface defects. Preliminary model calculations suggest that removing these states can increase the cell efficiency from 10% to 13.5%. Photon absorption in the CdS film also limits the cell performance, and eliminating this loss mechanism can result in CdTe efficiencies in excess of 18%. Polycrystalline, 1.7-e, CdZnTe films were also grown for tandem-cell applications. CdZnTe/CdS cells processed using the standard CdTe cell fabrication procedure resulted in 4.4% efficiency, high series resistance, and a band-gap shift to 1.55 eV. The formation of Zn-O at and near the CdZnTe surface is the source of high contact resistance. A saturated dichromate each prior to contact deposition was found to solve the contact resistance problem. The CdCl{sub 2} treatment was identified as the cause of the observed band-gap shift due to the preferred formation of ZnCl{sub 2}. 59 refs.

Rohatgi, A.; Sudharsanan, R.; Ringel, S. [Georgia Inst. of Tech., Atlanta, GA (United States)

1992-02-01

172

Solar cell radiation handbook  

NASA Technical Reports Server (NTRS)

Solar cell theory cells are manufactured, and how they are modeled mathematically is reviewed. The interaction of energetic charged particle radiation with solar cells is discussed in detail and the concept of 1 MeV equivalent electron fluence is introduced. The space radiation environment is described and methods of calculating equivalent fluences for the space environment are developed. A computer program was written to perform the equivalent fluence calculations and a FORTRAN listing of the program is included. Finally, an extensive body of data detailing the degradation of solar cell electrical parameters as a function of 1 MeV electron fluence is presented.

Tada, H. Y.; Carter, J. R., Jr.

1977-01-01

173

Development and interface/surface characterization of titanium dioxide and zinc oxide electron-collection interlayer materials for organic solar cells  

NASA Astrophysics Data System (ADS)

My research on metal oxide electron-harvesting interlayers for organic solar cells was focused as three interrelated projects in this dissertation: i) development of a chemical vapor deposition (CVD) system for TiO 2 film; ii) an electrochemical methodology to evaluate ZnO thin film charge (hole) blocking ability; iii) the effects of plasma modifications on sol-gel ZnO and sol-gel ZnO/organic (active layer) interfaces. In i), we showed that nanoscale (12-36 nm) CVD TiO2 film deposited at 210 oC obtains properties of conformal growth, superior hole blocking ability, stoichiometric metal to oxide ratio. The introduction of CVD TiO2 film as an electron transport layer into organic solar cell significantly improves its J-V characteristics. The optimum TiO2 thickness in the OPV device applications was found to be 24 nm with a high fill factor (0.58) and power conversion efficiency (3.7%) obtained. In ii), simple electrochemical methods, i.e., cyclic voltammetry, impedance spectroscopy have been used to evaluate sol-gel derived ZnO (sg-ZnO) and sputtered ZnO (sp-ZnO) porosity and pinhole density. We showed that sg-ZnO with high surface area porous structure allows the probe molecules and poly-thiophene (P3HT) thin layer to direct contact ITO substrate, whereas sp-ZnO with dense structural property efficiently eliminates these electroactivities. This electrochemical property difference also directly reflects on the device shunt resistance (Rp), where we observed larger leakage current for the devices using sg-ZnO than that of devices using sp-ZnO. In iii), we demonstrated low power radio frequency (RF) O2 and Ar plasma treatments have significant impacts on sg-ZnO near-surface chemical compositions, which in turn influence the onset potential of sg-ZnO electron injection and its energetic alignment with electron acceptors, e.g., C60. Using UPS, we found the presence of localized mid-gap states near the Fermi-level of sg-ZnO, which induces the most favorable band bending and the largest vacuum level shift due to significant electron transfer from sg-ZnO to C60. As a result, the resultant solar cells show the best device performance. Upon the plasma treatments, the passivation effects eliminate the mid-gap state. Therefore, we observed less degree of band bending at ZnO/C60 interface and poorer device performance for the plasma treated sg-ZnO.

Ou, Kai-Lin

174

High-efficiency solar cell and method for fabrication  

DOEpatents

A high-efficiency 3- or 4-junction solar cell is disclosed with a theoretical AM0 energy conversion efficiency of about 40%. The solar cell includes p-n junctions formed from indium gallium arsenide nitride (InGaAsN), gallium arsenide (GaAs) and indium gallium aluminum phosphide (InGaAlP) separated by n-p tunnel junctions. An optional germanium (Ge) p-n junction can be formed in the substrate upon which the other p-n junctions are grown. The bandgap energies for each p-n junction are tailored to provide substantially equal short-circuit currents for each p-n junction, thereby eliminating current bottlenecks and improving the overall energy conversion efficiency of the solar cell. Additionally, the use of an InGaAsN p-n junction overcomes super-bandgap energy losses that are present in conventional multi-junction solar cells. A method is also disclosed for fabricating the high-efficiency 3- or 4-junction solar cell by metal-organic chemical vapor deposition (MOCVD). 4 figs.

Hou, H.Q.; Reinhardt, K.C.

1999-08-31

175

High-efficiency solar cell and method for fabrication  

DOEpatents

A high-efficiency 3- or 4-junction solar cell is disclosed with a theoretical AM0 energy conversion efficiency of about 40%. The solar cell includes p-n junctions formed from indium gallium arsenide nitride (InGaAsN), gallium arsenide (GaAs) and indium gallium aluminum phosphide (InGaAlP) separated by n-p tunnel junctions. An optional germanium (Ge) p-n junction can be formed in the substrate upon which the other p-n junctions are grown. The bandgap energies for each p-n junction are tailored to provide substantially equal short-circuit currents for each p-n junction, thereby eliminating current bottlenecks and improving the overall energy conversion efficiency of the solar cell. Additionally, the use of an InGaAsN p-n junction overcomes super-bandgap energy losses that are present in conventional multi-junction solar cells. A method is also disclosed for fabricating the high-efficiency 3- or 4-junction solar cell by metal-organic chemical vapor deposition (MOCVD).

Hou, Hong Q. (Albuquerque, NM); Reinhardt, Kitt C. (Albuquerque, NM)

1999-01-01

176

Solar cell activation system  

SciTech Connect

A system for activating solar cells involves the use of phosphorescent paint, the light from which is amplified by a thin magnifying lens and used to activate solar cells. In a typical system, a member painted with phosphorescent paint is mounted adjacent a thin magnifying lens which focuses the light on a predetermined array of sensitive cells such as selenium, cadmium or silicon, mounted on a plastic board. A one-sided mirror is mounted adjacent the cells to reflect the light back onto said cells for purposes of further intensification. The cells may be coupled to rechargeable batteries or used to directly power a small radio or watch.

Apelian, L.

1983-07-05

177

Thermally evaporated fullerene (C70) to bridge the charge transport in between nanostructured zinc oxide and conjugated copolymer in hybrid solar cell  

NASA Astrophysics Data System (ADS)

We have investigated the effect of incorporating thin fullerene (C70) layer in between nanostructured ZnO and conjugated co-polymer PCDTBT (Poly [[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thophenediyl-2,1,3-benzothiadiazole- 4,7-diyl-2,5-thiophenediyl]) for photovoltaic device performance. The addition of the fullerene layer enhances the electron transfer at the heterojunction from polymer to the metal oxide. The reason for the enhanced performance is investigated and it is observed that the fullerene layer can improve charge transfer process thorough the reduction of the trap induced interfacial recombination. The fullerene introduction is also helping in effective charge transfer (CT) excitons dissociation and transport at the interface. Encouraging improvement of the device performance was observed with the incorporation of C70 in this kind of hybrid solar cells.

Pradhan, S.; Kumar, S.; Dhar, A.

2014-04-01

178

Zinc air refuelable battery: alternative zinc fuel morphologies and cell behavior  

SciTech Connect

Multicell zinc/air batteries have been tested previously in the laboratory and as part of the propulsion system of an electric bus; cut zinc wire was used as the anode material. This battery is refueled by a hydraulic transport of 0.5-1 mm zinc particles into hoppers above each cell. We report an investigation concerning alternative zinc fuel morphologies, and energy losses associated with refueling and with overnight or prolonged standby. Three types of fuel pellets were fabricated, tested and compared with results for cut wire: spheres produced in a fluidized bed electrolysis cell; elongated particles produced by gas-atomization; and pellets produced by chopping 1 mm porous plates made of compacted zinc fines. Relative sizes of the particles and cell gap dimensions are critical. All three types transported within the cell 1553 and showed acceptable discharge characteristics, but a fluidized bed approach appears especially attractive for owner/user recovery operations.

Cooper, J.F.; Krueger, R.

1997-01-01

179

Solar cell radiation handbook  

NASA Technical Reports Server (NTRS)

The handbook to predict the degradation of solar cell electrical performance in any given space radiation environment is presented. Solar cell theory, cell manufacturing and how they are modeled mathematically are described. The interaction of energetic charged particles radiation with solar cells is discussed and the concept of 1 MeV equivalent electron fluence is introduced. The space radiation environment is described and methods of calculating equivalent fluences for the space environment are developed. A computer program was written to perform the equivalent fluence calculations and a FORTRAN listing of the program is included. Data detailing the degradation of solar cell electrical parameters as a function of 1 MeV electron fluence are presented.

Tada, H. Y.; Carter, J. R., Jr.; Anspaugh, B. E.; Downing, R. G.

1982-01-01

180

Dye Sensitized Solar Cells  

PubMed Central

Dye sensitized solar cell (DSSC) is the only solar cell that can offer both the flexibility and transparency. Its efficiency is comparable to amorphous silicon solar cells but with a much lower cost. This review not only covers the fundamentals of DSSC but also the related cutting-edge research and its development for industrial applications. Most recent research topics on DSSC, for example, applications of nanostructured TiO2, ZnO electrodes, ionic liquid electrolytes, carbon nanotubes, graphene and solid state DSSC have all been included and discussed. PMID:20480003

Wei, Di

2010-01-01

181

NREL Scientists Spurred the Success of Multijunction Solar Cells (Fact Sheet)  

SciTech Connect

Before 1984, many scientists believed that high-quality gallium indium phosphide (GaInP) alloys could not be grown for use as semiconductors because the alloys would separate. One researcher at the Solar Energy Research Institute (SERI) thought differently. His name was Jerry Olson, and his innovative thinking changed solar history. Olson identified a material combination that allowed the multijunction cell to flourish. It is now the workhorse that powers satellites and the catalyst for renewed interest in concentrator photovoltaic (CPV) products.

Not Available

2012-09-01

182

Zinc transporters and their role in the pancreatic ?-cell.  

PubMed

Zinc is an essential nutrient with tremendous importance for human health, and zinc deficiency is a severe risk factor for increased mortality and morbidity. As abnormal zinc homeostasis causes diabetes, and because the pancreatic ?-cell contains the highest zinc content of any known cell type, it is of interest to know how zinc fluxes are controlled in ?-cells. The understanding of zinc homeostasis has been boosted by the discovery of multiprotein families of zinc transporters, and one of them - zinc transporter 8 (ZnT8) - is abundantly and specifically expressed in the pancreatic islets of Langerhans. In this review, we discuss the evidence for a physiological role of ZnT8 in the formation of zinc-insulin crystals, the physical form in which most insulin is stored in secretory granules. In addition, we cross-examine this information, collected in genetically modified mouse strains, to the knowledge that genetic variants of the human ZnT8 gene predispose to the onset of type 2 diabetes and that epitopes on the ZnT8 protein trigger autoimmunity in patients with type 1 diabetes. The overall conclusion is that we are still at the dawn of a complete understanding of how zinc homeostasis operates in normal ?-cells and how abnormalities lead to ?-cell dysfunction and diabetes. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2012.00199.x, 2012). PMID:24843567

Lemaire, Katleen; Chimienti, Fabrice; Schuit, Frans

2012-06-01

183

Photoelectrochemical Solar Cells.  

ERIC Educational Resources Information Center

This introduction to photoelectrochemical (PEC) cells reviews topics pertaining to solar energy conversion and demonstrates the ease with which a working PEC cell can be prepared with n-type silicon as the photoanode and a platinum counter electrode (both immersed in ethanolic ferrocene/ferricenium solutions). Experiments using the cell are

McDevitt, John T.

1984-01-01

184

Synthesis and processing of CdS/ZnS multilayer films for solar cell application  

E-print Network

chemical bath deposited CdS/ZnS multilayers through low-temperature chemical and thermal bath deposition; CdS thin films; ZnS thin films; Solar cell 1. Introduction The zinc-based binary layer in CdTe thin film solar cells. Since chemical bath deposition (CBD) is known to produce solar cell

Chow, Lee

185

Photovoltaic solar cell  

DOEpatents

A photovoltaic solar cell for generating electricity from sunlight is disclosed. The photovoltaic solar cell comprises a plurality of spaced-apart point contact junctions formed in a semiconductor body to receive the sunlight and generate the electricity therefrom, the plurality of spaced-apart point contact junctions having a first plurality of regions having a first doping type and a second plurality of regions having a second doping type. In addition, the photovoltaic solar cell comprises a first electrical contact electrically connected to each of the first plurality of regions and a second electrical contact electrically connected to each of the second plurality of regions, as well as a passivation layer covering major surfaces and sidewalls of the photovoltaic solar cell.

Nielson, Gregory N; Cruz-Campa, Jose Luis; Okandan, Murat; Resnick, Paul J

2014-05-20

186

Photovoltaic solar cell  

DOEpatents

A photovoltaic solar cell for generating electricity from sunlight is disclosed. The photovoltaic solar cell comprises a plurality of spaced-apart point contact junctions formed in a semiconductor body to receive the sunlight and generate the electicity therefrom, the plurality of spaced-apart point contact junctions having a first plurality of regions having a first doping type and a second plurality of regions having a second doping type. In addition, the photovoltaic solar cell comprises a first electrical contact electrically connected to each of the first plurality of regions and a second electrical contact electrically connected to each of the second plurality of regions, as well as a passivation layer covering major surfaces and sidewalls of the photovoltaic solar cell.

Nielson, Gregory N; Okandan, Murat; Cruz-Campa, Jose Luis; Resnick, Paul J

2013-11-26

187

Solar cell array interconnects  

DOEpatents

Electrical interconnects for solar cells or other electronic components using a silver-silicone paste or a lead-tin (Pb-Sn) no-clean fluxless solder cream, whereby the high breakage of thin (<6 mil thick) solar cells using conventional solder interconnect is eliminated. The interconnects of this invention employs copper strips which are secured to the solar cells by a silver-silicone conductive paste which can be used at room temperature, or by a Pb-Sn solder cream which eliminates undesired residue on the active surfaces of the solar cells. Electrical testing using the interconnects of this invention has shown that no degradation of the interconnects developed under high current testing, while providing a very low contact resistance value.

Carey, Paul G. (Mountain View, CA); Thompson, Jesse B. (Brentwood, CA); Colella, Nicolas J. (Livermore, CA); Williams, Kenneth A. (Livermore, CA)

1995-01-01

188

Integrated solar cell and battery  

SciTech Connect

An integrated solar cell and battery is described comprising: (a) a substrate; and (b) a solar cell and a thin film battery including a solid electrolyte, deposited by thin film deposition techniques on the substrate; (c) the substrate and the solar cell together comprising a bulk type solar cell.

Little, R.G.

1988-04-26

189

Thin silicon solar cells  

SciTech Connect

The silicon-film design achieves high performance by using a dun silicon layer and incorporating light trapping. Optimally designed thin crystalline solar cells (<50 microns thick) have performance advantages over conventional thick devices. The high-performance silicon-film design employs a metallurgical barrier between the low-cost substrate and the thin silicon layer. Light trapping properties of silicon-film on ceramic solar cells are presented and analyzed. Recent advances in process development are described here.

Hall, R.B.; Bacon, C.; DiReda, V.; Ford, D.H.; Ingram, A.E.; Cotter, J.; Hughes-Lampros, T.; Rand, J.A.; Ruffins, T.R.; Barnett, A.M. [Astro Power Inc., Solar Park, Newark, DE (United States)

1992-12-01

190

Inside a Solar Cell  

NSDL National Science Digital Library

Based on a NOVA Online lesson, Teachers' Domain presents this interactive activity that provides reading material and animations to help students learn the basics of photovoltaic cells, including how a solar cell converts solar energy into electricity and the components of the unit (silicon layers, metal backing, antireflective coating, and metal conductor strips). On the site, visitors will also find a supplemental background essay, discussion questions, and standards alignment from Teachers' Domain.

191

Lightweight solar cell  

SciTech Connect

A lightweight solar cell is described comprising: (a) an LD aerogel substrate having a density of between 10-1,000 mg/cc, the surface of the substrate being polished (b) a dielectric planarization layer being applied to the polished surface, and (c) at least one layer of PV material deposited thereon. The solar cell having a plurality of PV layers deposited on the planarization layer.

Hotaling, S.P.

1993-06-22

192

Screening of solar cells  

SciTech Connect

Because solar cells in a production batch are not identical, screening is performed to obtain similar cells for aggregation into arrays. A common technique for screening is based on a single operating point of the I-V characteristic of the cell, usually the maximum power point. As a result, inferior cell matching may occur at the actual operating points. Screening solar cells based on the entire I-V characteristic will inherently result in more similar cells in the array. An array consisting of more similar cells is likely to have better overall characteristics and more predictable performance. Solar cell screening methods and cell ranking are discussed. The concept of a mean cell is defined as a cell 'best' representing all the cells in the production batch. The screening and ranking of all cells are performed with respect to the mean cell. The comparative results of different screening methods are illustrated on a batch of 50 silicon cells of the Space Station Freedom.

Appelbaum, J.; Chait, A.; Thompson, D.A.

1993-07-01

193

Zinc transporter 8 (ZnT8) and ? cell function.  

PubMed

Human pancreatic ? cells have exceptionally high zinc content. In ? cells the highest zinc concentration is in insulin secretory granules, from which it is cosecreted with the hormone. Uptake of zinc into secretory granules is mainly mediated by zinc transporter 8 (ZnT8), the product of the SLC30A8 [solute carrier family 30 (zinc transporter), member 8] gene. The minor alleles of several single-nucleotide polymorphisms (SNPs) in SLC30A8 are associated with decreased risk of type 2 diabetes (T2D), but the precise mechanisms underlying the protective effects remain uncertain. In this article we review current knowledge of the role of ZnT8 in maintaining zinc homeostasis in ? cells, its role in glucose metabolism based on knockout mouse studies, and current theories regarding the link between ZnT8 function and T2D. PMID:24751356

Davidson, Howard W; Wenzlau, Janet M; O'Brien, Richard M

2014-08-01

194

Spray deposited copper zinc tin sulphide (Cu2ZnSnS4) film as a counter electrode in dye sensitized solar cells.  

PubMed

Stoichiometric thin films of Cu2ZnSnS4 (CZTS) were deposited by the spray technique on a FTO coated glass substrate, with post-annealing in a H2S environment to improve the film properties. CZTS films were used as a counter electrode (CE) in Dye-Sensitized Solar Cells (DSCs) with N719 dye and an iodine electrolyte. The DSC of 0.25 cm(2) area using a CE of CZTS film annealed in a H2S environment under AM 1.5G illumination (100 mW cm(-2)) exhibited a short circuit current density (JSC) = 18.63 mA cm(-2), an open circuit voltage (VOC) = 0.65 V and a fill factor (FF) = 0.53, resulting in an overall power conversion efficiency (PCE) = 6.4%. While the DSC using as deposited CZTS film as a CE showed the PCE = 3.7% with JSC = 13.38 mA cm(-2), VOC = 0.57 V and FF = 0.48. Thus, the spray deposited CZTS films can play an important role as a CE in the large area DSC fabrication. PMID:25286339

Swami, Sanjay Kumar; Chaturvedi, Neha; Kumar, Anuj; Chander, Nikhil; Dutta, Viresh; Kumar, D Kishore; Ivaturi, A; Senthilarasu, S; Upadhyaya, Hari M

2014-11-21

195

Inside a Solar Cell  

NSDL National Science Digital Library

This set of six interactive slides showcases how a typical photovoltaic cell converts solar energy into electricity. Explore the components of a photovoltaic cell, including the silicon layers, metal backing, antireflective coating, and metal conductor strips. Using animations, investigate why the silicon layers are doped with phosphorous and boron, and how an electric field is used to generate electricity from sunlight.

NOVA

196

Transparent solar cell module  

NASA Technical Reports Server (NTRS)

Modified solar cell module uses high transmission glass and adhesives, and heat dissipation to boost power per unit area by 25% (9.84% efficiency based on cell area at 60 C and 100 mW/sq cm flux). Design is suited for automatic production and is potentially more cost effective.

Antonides, G. J.; Dillard, P. A.; Fritz, W. M.; Lott, D. P.

1979-01-01

197

Parameterization of solar cells  

NASA Technical Reports Server (NTRS)

The aggregation (sorting) of the individual solar cells into an array is commonly based on a single operating point on the current-voltage (I-V) characteristic curve. An alternative approach for cell performance prediction and cell screening is provided by modeling the cell using an equivalent electrical circuit, in which the parameters involved are related to the physical phenomena in the device. These analytical models may be represented by a double exponential I-V characteristic with seven parameters, by a double exponential model with five parameters, or by a single exponential equation with four or five parameters. In this article we address issues concerning methodologies for the determination of solar cell parameters based on measured data points of the I-V characteristic, and introduce a procedure for screening of solar cells for arrays. We show that common curve fitting techniques, e.g., least squares, may produce many combinations of parameter values while maintaining a good fit between the fitted and measured I-V characteristics of the cell. Therefore, techniques relying on curve fitting criteria alone cannot be directly used for cell parameterization. We propose a consistent procedure which takes into account the entire set of parameter values for a batch of cells. This procedure is based on a definition of a mean cell representing the batch, and takes into account the relative contribution of each parameter to the overall goodness of fit. The procedure is demonstrated on a batch of 50 silicon cells for Space Station Freedom.

Appelbaum, J.; Chait, A.; Thompson, D.

1992-01-01

198

Effects of number and position of meta and para carboxyphenyl groups of zinc porphyrins in dye-sensitized solar cells: structure-performance relationship.  

PubMed

Porphyrin sensitizers containing meta- and para-carboxyphenyl groups in their meso positions have been synthesized and investigated for their performance in dye-sensitized solar cells (DSSCs). The superior performance of para-derivative compared to meta-derivative porphyrins was revealed by optical spectroscopy, electrochemical property measurements, density functional theory (DFT) calculations, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, incident photon-to-current conversion efficiency (IPCE), electrochemical impedance spectroscopy (EIS), and stability performance. Absorption spectra of para-carboxyphenyl-substituted porphyrins on TiO2 show a broader Soret band compared to meta-carboxyphenyl-substituted porphyrins. ATR-FTIR spectra of the studied porphyrins on TiO2 were applied to investigate the number and mode of carboxyl groups attached to TiO2. The VOC, JSC, and IPCE values of para-series porphyrins were distinctly superior to those of meta-series porphyrins. The Nyquist plots of the studied porphyrins show that charge injection in para-series porphyrins is superior to that in meta-series porphyrins. The orthogonally positioned para derivatives have more efficient charge injection and charge transfer over charge recombination, whereas the efficiencies of flat-oriented meta derivatives are retarded by rapid charge recombination. Photovoltaic measurements of the studied meta- and para-carboxyphenyl-functionalized porphyrins show that the number and position of carboxyphenyl groups play a crucial role in the performance of the DSSC. Our results indicate that para-carboxyphenyl derivatives outperform meta-carboxyphenyl derivatives to give better device performance. This study will serve as a guideline for the design and development of organic, porphyrin, and ruthenium dyes in DSSCs. PMID:25562465

Ambre, Ram B; Mane, Sandeep B; Chang, Gao-Fong; Hung, Chen-Hsiung

2015-01-28

199

Broad spectrum solar cell  

DOEpatents

An alloy having a large band gap range is used in a multijunction solar cell to enhance utilization of the solar energy spectrum. In one embodiment, the alloy is In.sub.1-xGa.sub.xN having an energy bandgap range of approximately 0.7 eV to 3.4 eV, providing a good match to the solar energy spectrum. Multiple junctions having different bandgaps are stacked to form a solar cell. Each junction may have different bandgaps (realized by varying the alloy composition), and therefore be responsive to different parts of the spectrum. The junctions are stacked in such a manner that some bands of light pass through upper junctions to lower junctions that are responsive to such bands.

Walukiewicz, Wladyslaw (Kensington, CA); Yu, Kin Man (Lafayette, CA); Wu, Junqiao (Richmond, CA); Schaff, William J. (Ithaca, NY)

2007-05-15

200

EE580 Solar Cells Todd J. Kaiser  

E-print Network

7/21/2010 1 EE580 ­ Solar Cells Todd J. Kaiser · Lecture 06 · Solar Cell Materials & Structures 1Montana State University: Solar Cells Lecture 6: Solar Cells Solar Cell Technologies · A) Crystalline Silicon · B) Thin Film · C) Group III-IV Cells 2Montana State University: Solar Cells Lecture 6: Solar

Kaiser, Todd J.

201

Bilayer heterojunction solar cell based on naphthalene bis-benzimidazole  

Microsoft Academic Search

We have fabricated a bilayer heterojunction solar cell consisting of pn active layers of naphthalenetetracarboxylic bis-benzimidazole, N-CON, and zinc phthalocyanine, ZnPc. Conjugated naphthalene derivative of naphthalene bis-benzimidazole was employed as an electron acceptor. Bilayer solar cells were produced by successive evaporation of zinc phthalocyanine, ZnPc, and naphthalene bis-benzimidazole, N-CON, on glass substrates coated with indium doped tin oxide, ITO\\/PEDOT:PSS\\/ZnPc\\/N-CON\\/Al. Photovoltaic

Sule Erten; Siddik Icli

2008-01-01

202

Aluminium phosphide poisoning.  

PubMed

We describe a lethal poisoning in a healthy woman caused by deliberate ingestion of aluminium phosphide (AlP), a pesticide used to kill rodents and insects. Toxicity of AlP and review of cases reported to the National Poisons Information Service (London) 1997-2003 are discussed. PMID:16373788

Bogle, R G; Theron, P; Brooks, P; Dargan, P I; Redhead, J

2006-01-01

203

Flexible Solar Cells  

NASA Technical Reports Server (NTRS)

Solar cell "modules" are plastic strips coated with thin films of photovoltaic silicon that collect solar energy for instant conversion into electricity. Lasers divide the thin film coating into smaller cells to build up voltage. Developed by Iowa Thin Film Technologies under NASA and DOE grants, the modules are used as electrical supply for advertising displays, battery rechargers for recreational vehicles, and to power model airplanes. The company is planning other applications both in consumer goods and as a power source in underdeveloped countries.

1994-01-01

204

Solar cell radiation handbook  

NASA Technical Reports Server (NTRS)

A method is presented for predicting the degradation of a solar array in a space radiation environment. Solar cell technology which emphasizes the cell parameters that degrade in a radiation environment, is discussed along with the experimental techniques used in the evaluation of radiation effects. Other topics discussed include: theoretical aspects of radiation damage, methods for developing relative damage coefficients, nature of the space radiation environment, method of calculating equivalent fluence from electron and proton energy spectrums and relative damage coefficients, and comparison of flight data with estimated degradation.

Carter, J. R., Jr.; Tada, H. Y.

1973-01-01

205

III-V solar cells and doping processes  

SciTech Connect

A tandem solar cell concentrator module is described comprising: (a) a concentrator lens for focusing incident solar radiation; (b) a tandem solar cell substantially at the focus of the lens, the cell including: (i) an upper AlGaAs/GaAs primary cell having: (1) an AlGaAs window covering a photoactive region of a generally n-type GaAs wafer, and (2) a zinc-diffused, p-type emitter region having a concentration of zinc of between about 10[sup 18]-10[sup 19] atoms/cm[sup 3]; and (ii) a lower GaSb booster cell positioned to receive solar radiation that passes through the primary cell, the booster cell including grid lines on the upper surface for collecting current produced in the booster cell by incident radiation, a heavy concentration of zinc under the rid lines to provide low ohmic contact resistance, and a light concentration of zinc between the grid lines, the light concentration being effective to preserve the minority carrier lifetime in the booster cell to increase the short circuit current; wherein the booster cell includes texture etching to increase the conversion efficiency and to reduce reflection losses, the etching patterning the booster cell in the regions between the grid lines, and includes a backside metallization comprising layers of indium tin oxide, titanium tungsten nitride, and silver overlying one another, the indium tin oxide adjacent the GaSb and the silver at the exposed surface; (c) a heat spreader attached to both the primary cell and booster cell for holding the two in proper spaced relationship and for conveying excess heat away from either to a heat sink; and (d) current collection means connected to the primary cell and booster cell for collecting current generated in both when solar radiation is focused on the module.

Fraas, L.M.; Sundaram, V.S.; Avery, J.E.; Gruenhaum, P.E.; Malocsay, E.

1993-06-08

206

TJ Solar Cell  

SciTech Connect

This talk will discuss recent developments in III-V multijunction photovoltaic technology which have led to the highest-efficiency solar cells ever demonstrated. The relationship between the materials science of III-V semiconductors and the achievement of record solar cell efficiencies will be emphasized. For instance, epitaxially-grown GAInP has been found to form a spontaneously-ordered GaP/InP (111) superlattice. This ordering affects the band gap of the material, which in turn affects the design of solar cells which incorporate GaInP. For the next generation of ultrahigh-efficiency III-V solar cells, we need a new semiconductor which is lattice-matched to GaAs, has a band gap of 1 eV, and has long minority-carrier diffusion lengths. Out of a number of candidate materials, the recently-discovered alloy GaInNAs appears to have the greatest promise. This material satisfies the first two criteria, but has to date shown very low diffusion lengths, a problem which is our current focus in the development of these next-generation cells.

Daniel Friedman

2009-04-17

207

Solar cells for solar power satellites  

NASA Technical Reports Server (NTRS)

The concept of a solar-cell array for a solar power satellite is developed to permit evaluation of its economic feasibility for generating power for delivery to public utilities on earth. Gallium arsenide solar cells were considered but it could not be assured that the world gallium resources could support constructions of two solar power satellites per year. Therefore, for preliminary design an array blanket made from 5 by 10 cm silicon solar cells, 50 microns thick, and electrostatically bonded between borosilicate glass sheets was adopted. In annealing experiments, a radiated 50 microns thick cell was restored to its initial performance in a 500 C. Solar-cell efficiency effects significantly the solar power satellite mass, which varies from 90,000 metric tons for 20 percent cells to 120,000 metric tons for 12 percent cells. The anticipated cost of delivered power, based on 1977 dollars, varies from 4 cents per kWh with 18 percent cells, to 5 cents per kWh for 12 percent efficient cells.

Oman, H.

1978-01-01

208

ZINC  

EPA Science Inventory

This report summarizes the available information on zinc as it relates to its effects on man and his environment. Zinc is found in most soils, but some areas are deficient in it. Metallurgic operations contribute to zinc contamination in air, water and soil. Trace amounts of zinc...

209

NASA Facts, Solar Cells.  

ERIC Educational Resources Information Center

The design and function of solar cells as a source of electrical power for unmanned space vehicles is described in this pamphlet written for high school physical science students. The pamphlet is one of the NASA Facts Science Series (each of which consists of four pages) and is designed to fit in the standard size three-ring notebook. Review

National Aeronautics and Space Administration, Washington, DC.

210

Photoelectric solar cell array  

Microsoft Academic Search

A photoelectric solar cell device comprises a dispersing element exposed to the sun's radiation and followed in the optical path by photocells having different spectral sensitivities. Each photocell has its working surface so oriented that the light beam with the wavelength corresponding to the maximum spectral sensitivity of that photocell impinges on its working surface. The dispersing element is a

N. S. Lidorenko; V. V. Afian; R. G. Martirosian; S. V. Ryabikov; D. S. Strebkov; A. V. Vartanian

1983-01-01

211

Ingestion of gallium phosphide nanowires has no adverse effect on Drosophila tissue function  

NASA Astrophysics Data System (ADS)

Engineered nanoparticles have been under increasing scrutiny in recent years. High aspect ratio nanoparticles such as carbon nanotubes and nanowires have raised safety concerns due to their geometrical similarity to asbestos fibers. III-V epitaxial semiconductor nanowires are expected to be utilized in devices such as LEDs and solar cells and will thus be available to the public. In addition, clean-room staff fabricating and characterizing the nanowires are at risk of exposure, emphasizing the importance of investigating their possible toxicity. Here we investigated the effects of gallium phosphide nanowires on the fruit fly Drosophila melanogaster. Drosophila larvae and/or adults were exposed to gallium phosphide nanowires by ingestion with food. The toxicity and tissue interaction of the nanowires was evaluated by investigating tissue distribution, activation of immune response, genome-wide gene expression, life span, fecundity and somatic mutation rates. Our results show that gallium phosphide nanowires applied through the diet are not taken up into Drosophila tissues, do not elicit a measurable immune response or changes in genome-wide gene expression and do not significantly affect life span or somatic mutation rate.

Adolfsson, Karl; Schneider, Martina; Hammarin, Greger; Hcker, Udo; Prinz, Christelle N.

2013-07-01

212

Solar-cell panel simulator  

Microsoft Academic Search

The energy generated by solar cells can be transformed into ac power by means of inverters. In most cases these inverters cannot be tested under real conditions, since large solar-cell arrays are not yet available at reasonable prices. Therefore, a circuit that simulates a solar-cell array has been developed.

D. Baert

1979-01-01

213

Transparent electrode materials for solar cells  

NASA Astrophysics Data System (ADS)

Alternatives for replacing the expensive ITO are explored and Poly(ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS) is introduced as one possibility. We present the first small-molecule organic solar cells employing only PEDOT:PSS as transparent electrode. Solar cells on glass and on flexible plastic foil were prepared, using a p-doped hole transporting material, zinc phthalocyanine (ZnPc) and C60 as donor-acceptor heterojunction, and an exciton blocking layer. Different methods to structure the PEDOT:PSS electrodes were investigated and are presented. As proof of principle, non-optimized prototype cells with efficiencies of over 0.7% on glass and 0.9% on flexible plastic foil substrate were obtained.

Meiss, Jan; Uhrich, Christian L.; Fehse, Karsten; Pfuetzner, Steffen; Riede, Moritz K.; Leo, Karl

2008-04-01

214

High efficiency solar cell structure  

SciTech Connect

The invention relates to a new-type of solar cell structure, and to a method of manufacturing same. The solar cell is designated as an MINP cell (Metal-Insulator-NP junction solar cell). Essentially, the MINP solar cell is an extremely shallow N-P junction cell with a MIS (Metal-Insulator-Semiconductor) type contact made to the top of the cell. Although combining features of the two technologies, no more processing steps are required than for a conventional P-N junction cell. The advantage of the MINP structure is its substantially improved efficiency.

Green, M.A.; Blakers, A.W.

1983-09-13

215

Development and fabrication of large vented nickel-zinc cells  

NASA Technical Reports Server (NTRS)

A preliminary cell design for a 300AH vented nickel-zinc cell was established based on volume requirements and cell component materials selected by NASA Lewis Research Center. A 100AH cell configuration was derived from the 300AH cell design utilizing the same size electrodes, separators, and cell terminal hardware. The first cells fabricated were four groups of three cells each in the 100AH size. These 100AH experimental nickel-zinc cells had as common components the nickel positive electrodes (GFM), flexible inorganic separator (GFM) bags on the negative electrodes, pressed powder zinc oxide electrodes, and cell containers with hardware. The variations introduced were four differing electrolyte absorber (interseparator) systems used to encase the nickel positive electrodes of each cell group. The four groups of 100AH experimental vented nickel-zinc cells were tested to determine, based on cell performance, the best two interseparator systems. Using the two interseparator systems, two groups of experimental 300AH cells were fabricated. Each group of three cells differed only in the interseparator material used. The six cells were filled, formed and tested to evaluate the interseparator materials and investigate the performance characteristics of the 300AH cell configuration and its components.

Donnel, C. P., III

1975-01-01

216

Theoretical investigation of the charge-transfer properties in different meso-linked zinc porphyrins for highly efficient dye-sensitized solar cells.  

PubMed

The charge transfer effect of different meso-substituted linkages on porphyrin analogue 1 (A1, B1 and C1) was theoretically investigated using density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. The calculated geometry parameters and natural bond orbital analysis reveal that the twisted conformation between porphyrin macrocycle and meso-substituted linkages leads to blocking of the conjugation of the conjugated backbone, and the frontier molecular orbital plot shows that the intramolecular charge transfer of A1, B1 and C1 hardly takes place. In an attempt to improve the photoinduced intramolecular charge transfer ability of the meso-linked zinc porphyrin sensitizer, a strong electron-withdrawing group (CN) was introduced into the anchoring group of analogue 1 forming analogue 2 (A2, B2 and C2). The density difference plot of A2, B2 and C2 shows that the charge transfer properties dramatically improved. The electron injection process has been performed using TDDFT; the direct charge-transfer transition in the A2-(TiO2)38 interacting system takes place; our results strongly indicated that introducing electron-withdrawing groups into the acceptor part of porphyrin dyes can fine-tune the effective conjugation length of the ?-spacer and improve intramolecular charge transfer properties, consequently inducing the electron injection process from the anchoring group of the porphyrin dye to the (TiO2)38 surface which may improve the conversion efficiency of the DSSCs. Our calculated results can provide valuable information and a promising outlook for computation-aided sensitizer design with anticipated good properties in further experimental synthesis. PMID:24810141

Namuangruk, Supawadee; Sirithip, Kanokkorn; Rattanatwan, Rattanawelee; Keawin, Tinnagon; Kungwan, Nawee; Sudyodsuk, Taweesak; Promarak, Vinich; Surakhot, Yaowarat; Jungsuttiwong, Siriporn

2014-06-28

217

Modulation of Glycine Receptors in Retinal Ganglion Cells by Zinc  

Microsoft Academic Search

Effects of zinc, an endogenous neuromodulator in the central nervous system, on glycine receptors (GlyRs) in retinal ganglion cells were investigated by using the whole-cell voltage-clamp technique. Zn2+ at low concentration (10 mu M) suppressed it. This biphasic regulatory action of zinc acted selectively on the fast component of the glycine-induced current mediated by the strychnine-sensitive GlyRs, but not on

Yi Han; Samuel M. Wu

1999-01-01

218

Modeling of high efficiency solar cells under laser pulse for power beaming applications  

NASA Technical Reports Server (NTRS)

Solar cells have been used to convert sunlight to electrical energy for many years and also offer great potential for non-solar energy conversion applications. Their greatly improved performance under monochromatic light compared to sunlight, makes them suitable as photovoltaic (PV) receivers in laser power beaming applications. Laser beamed power to a PV array receiver could provide power to satellites, an orbital transfer vehicle, or a lunar base. Gallium arsenide (GaAs) and indium phosphide (InP) solar cells have calculated efficiencies of more than 50 percent under continuous illumination at the optimum wavelength. Currently high power free-electron lasers are being developed which operate in pulsed conditions. Understanding cell behavior under a laser pulse is important in the selection of the solar cell material and the laser. An experiment by NAsA lewis and JPL at the AVLIS laser facility in Livermore, CA presented experimental data on cell performance under pulsed laser illumination. Reference 5 contains an overview of technical issues concerning the use of solar cells for laser power conversion, written before the experiments were performed. As the experimental results showed, the actual effects of pulsed operation are more complicated. Reference 6 discusses simulations of the output of GaAs concentrator solar cells under pulsed laser illumination. The present paper continues this work, and compares the output of Si and GaAs solar cells.

Jain, Raj K.; Landis, Geoffrey A.

1994-01-01

219

Fabrication and testing of sealed silver-zinc cells  

NASA Technical Reports Server (NTRS)

A number of Type HS40-7 sealed silver-zinc cells and experimental 40AH sealed silver-zinc cells were fabricated. Cells of each experimental group contained one variation from the standard configuration (HS40-7) cell. Cells from each of five experimental cell groups and cells of the standard configuration were tested to characterize voltage and capacity performance at various discharge rates. The test cells were then subjected to 100 percent DOD Cycle Life Testing at 22 C. Results indicate that material and/or process variations are available which will improve both performance and cycle life of the existing 40 ampere-hour sealed silver-zinc cell configurations. The average cycle life to 50 percent loss of nominal capacity in cells from two (2) of the experimental groups was 150 - 165 cycles. A series of 12 ampere-hour cells was fabricated and tested as part of a program to incorporate the 40AH sealed silver-zinc cell fabrication technology into a cell of smaller size. Base-line configuration cells and experimental variations were produced using the HS40-7 cell fabrication and processing methods adapted to the smaller cell size.

Donnel, C. P., III

1976-01-01

220

EE580 Solar Cells Todd J. Kaiser  

E-print Network

7/21/2010 1 EE580 ­ Solar Cells Todd J. Kaiser · Lecture 08 · Solar Cell Characterization 1Montana State University: Solar Cells Lecture 8: Characterization Solar Cell Operation n Emitter p Base Rear completing the circuit 2Montana State University: Solar Cells Lecture 8: Characterization Solar Cell

Kaiser, Todd J.

221

Effect of zinc supplementation on incidence of infections and hospital admissions in sickle cell disease (SCD)  

Microsoft Academic Search

Zinc deficiency is a common nutritional problem in adult sickle-cell disease (SCD) pa- tients. Hyperzincuria and increased requirement of zinc due to continued hemolysis in SCD are probable bases for zinc deficiency in these patients. Zinc deficiency affects adversely T-helper1 (TH1) functions and cell mediated immunity and interleukin (IL)-2 production is decreased in zinc deficient subjects. We hypothesized that zinc

Ananda S. Prasad; Frances W. J. Beck; Joseph Kaplan; Pranatharthi H. Chandrasekar; Jesus Ortega; James T. Fitzgerald; Paul Swerdlow

1999-01-01

222

Solar PV- How A Solar Cell Works  

NSDL National Science Digital Library

The Advanced Technology Environmental and Energy Center (ATEEC) provides this document which will help instructors or anyone who would like to understand the basics of solar power and solar cells. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

Levander, Alejandro

223

ZnSe Films in GaAs Solar Cells  

NASA Technical Reports Server (NTRS)

ZnSe increases efficiency and conserves material. Two proposed uses of zinc selenide films promise to boost performance and reduce cost of gallium arsenide solar cells. Accordingly ZnSe serves as surface-passivation layer and as sacrificial layer enabling repeated use of costly GaAs substrate in fabrication.

Kachare, Ram H.

1987-01-01

224

EDITORIAL: Nanostructured solar cells Nanostructured solar cells  

NASA Astrophysics Data System (ADS)

Conversion into electrical power of even a small fraction of the solar radiation incident on the Earth's surface has the potential to satisfy the world's energy demands without generating CO2 emissions. Current photovoltaic technology is not yet fulfilling this promise, largely due to the high cost of the electricity produced. Although the challenges of storage and distribution should not be underestimated, a major bottleneck lies in the photovoltaic devices themselves. Improving efficiency is part of the solution, but diminishing returns in that area mean that reducing the manufacturing cost is absolutely vital, whilst still retaining good efficiencies and device lifetimes. Solution-processible materials, e.g. organic molecules, conjugated polymers and semiconductor nanoparticles, offer new routes to the low-cost production of solar cells. The challenge here is that absorbing light in an organic material produces a coulombically bound exciton that requires dissociation at a donor-acceptor heterojunction. A thickness of at least 100 nm is required to absorb the incident light, but excitons only diffuse a few nanometres before decaying. The problem is therefore intrinsically at the nano-scale: we need composite devices with a large area of internal donor-acceptor interface, but where each carrier has a pathway to the respective electrode. Dye-sensitized and bulk heterojunction cells have nanostructures which approach this challenge in different ways, and leading research in this area is described in many of the articles in this special issue. This issue is not restricted to organic or dye-sensitized photovoltaics, since nanotechnology can also play an important role in devices based on more conventional inorganic materials. In these materials, the electronic properties can be controlled, tuned and in some cases completely changed by nanoscale confinement. Also, the techniques of nanoscience are the natural ones for investigating the localized states, particularly at surfaces and interfaces, which are often the limiting factor in device performance. This issue provides concrete examples of how the techniques of nanoscience and nanotechnology can be used to understand, control and optimize the performance of novel photovoltaic devices. We are grateful to the contributors for submitting high-quality papers around a common theme, even though they may not normally consider their work to fall under the banner of 'nanotechnology'. We would also like to thank the editorial and production staff at Nanotechnology for their efficient and speedy work in putting this issue together.

Greenham, Neil C.; Grtzel, Michael

2008-10-01

225

Nanowire Solar Cells  

NASA Astrophysics Data System (ADS)

The nanowire geometry provides potential advantages over planar wafer-based or thin-film solar cells in every step of the photoconversion process. These advantages include reduced reflection, extreme light trapping, improved band gap tuning, facile strain relaxation, and increased defect tolerance. These benefits are not expected to increase the maximum efficiency above standard limits; instead, they reduce the quantity and quality of material necessary to approach those limits, allowing for substantial cost reductions. Additionally, nanowires provide opportunities to fabricate complex single-crystalline semiconductor devices directly on low-cost substrates and electrodes such as aluminum foil, stainless steel, and conductive glass, addressing another major cost in current photovoltaic technology. This review describes nanowire solar cell synthesis and fabrication, important characterization techniques unique to nanowire systems, and advantages of the nanowire geometry.

Garnett, Erik C.; Brongersma, Mark L.; Cui, Yi; McGehee, Michael D.

2011-08-01

226

Quantum Dot Solar Cells  

NASA Technical Reports Server (NTRS)

We have been investigating the synthesis of quantum dots of CdSe, CuInS2, and CuInSe2 for use in an intermediate bandgap solar cell. We have prepared a variety of quantum dots using the typical organometallic synthesis routes pioneered by Bawendi, et. al., in the early 1990's. However, unlike previous work in this area we have also utilized single-source precursor molecules in the synthesis process. We will present XRD, TEM, SEM and EDS characterization of our initial attempts at fabricating these quantum dots. Investigation of the size distributions of these nanoparticles via laser light scattering and scanning electron microscopy will be presented. Theoretical estimates on appropriate quantum dot composition, size, and inter-dot spacing along with potential scenarios for solar cell fabrication will be discussed.

Raffaelle, Ryne P.; Castro, Stephanie L.; Hepp, Aloysius; Bailey, Sheila G.

2002-01-01

227

Nanocrystalline electrochemical solar cells  

SciTech Connect

Standard solar cells exploit the physics of semiconductors in which the energy of absorbed photons excites charge-carrier pairs which are subsequently separated by the influence of a solid state junction to provide a photovoltage. In the nanocrystalline electrochemical cell, the optical absorber is a dye monolayer which after photo-excitation injects electrons into a semiconductor substrate, with charge neutrality being restored by a chemical redox reaction. The circuit is completed through an electrolyte and a metallic counterlectrode. Present performance, industrial engagement in research and development and commercial prospects are presented.

McEvoy, A.J.; Graetzel, M. [Ecole Polytechnique Federale, Lausanne (Switzerland). Inst. de Chimie-Physique; Wittkopf, H.; Jestel, D.; Benemann, J. [Flachglas AG, Gelsenkirchen (Germany)

1994-12-31

228

Open Zinc Freezing-Point Cell Assembly and Evaluation  

NASA Astrophysics Data System (ADS)

An open metal freezing-point cell design has been developed in the Laboratory of Metrology and Quality. According to our design, a zinc cell was successfully assembled. The paper presents the needed parts for the cell, the cleaning process, and sealing of the cell. The assembled cell was then evaluated by comparison with two commercial closed zinc cells of different manufacturers. The freezing plateaus of the cells were measured, and a direct cell comparison was made. It was shown that the assembled open cell performed better than the used closed cell and was close to the brand new closed cell. The nominal purity of the zinc used for the open cell was 7 N, but the freezing plateau measurement suggests a higher impurity concentration. It was assumed that the zinc was contaminated to some extent during the process of cutting as its original shape was an irregular cylinder. The uncertainty due to impurities for the assembled cell is estimated to be 0.3 mK. Furthermore, the immersion profile and the pressure coefficient were measured. Both results are close to their theoretical values.

uek, V.; Batagelj, V.; Drnovek, J.; Bojkovski, J.

2014-07-01

229

Induction of apoptosis in mammalian cells by cadmium and zinc.  

PubMed Central

In various mammalian cells, two group IIb metals, cadmium and zinc, induce several morphological and biochemical effects that are salient features of programmed cell death. In C6 rat glioma cells, cadmium caused externalization of phosphatidylserine, breakdown of the mitochondrial membrane potential, activation of caspase-9, internucleosomal DNA fragmentation, chromatin condensation, and nuclear fragmentation. In NIH3T3 murine fibroblasts, cadmium-induced apoptosis was inhibited by overexpression of the antiapoptotic protein Bcl-2. Cadmium-induced DNA fragmentation in C6 cells was independent of inhibition of protein kinase A (PKA), protein kinase C (PKC), mitogen-activated protein kinase (MAPK), phosphatidylinositol-3-kinase, Ca-calmodulin-dependent protein kinase, and protein kinase G. Zinc at moderate concentrations (10-50 microM) protected against programmed cell death induced by cadmium, whereas deprivation of zinc by the membrane-permeable chelator N,N,N',N-terakis-(2-pyridylmethyl)ethylenediamine (TPEN) caused cell death with features characteristic of apoptosis. On the other hand, at elevated extracellular levels (150-200 microM), zinc alone caused programmed cell death in C6 cells. Zinc-induced apoptosis was independent of inhibition of PKA, PKC, guanylate cyclase and MAPK, but it was suppressed in the presence of 100 microM lanthanum chloride. PMID:12426148

Wtjen, Wim; Haase, Hajo; Biagioli, Marta; Beyersmann, Detmar

2002-01-01

230

Assembling solar-cell arrays  

NASA Technical Reports Server (NTRS)

Modified 70 mm movie film editor automatically attaches solar cells to flexible film substrate. Machine can rapidly and inexpensively assemble cells for solar panels at rate of 250 cells per minute. Further development is expected to boost production rate to 1000 cells per minute.

Bloch, J. T.; Hanger, R. T.; Nichols, F. W.

1979-01-01

231

Interleukin-1 stimulates zinc uptake by human thymic epithelial cells  

SciTech Connect

Thymic epithelial cells (TEC) are known to secrete peptides which influence the differentiation and maturation of T-lymphocytes. These peptides include the thymic hormones thymulin, thymosin-{alpha}1, and thymopoietin. The biological activity of thymulin is dependent on the presence of zinc in an equimolar ratio. The authors have shown that both interleukin-1{alpha}(IL-1{alpha}) and interleukin-1{beta}(IL-1{beta}), which stimulate proliferation of TEC, stimulate the uptake of Zn-65 in-vitro independent of this proliferation. Mitomycin-C was used to inhibit the proliferation of TEC. Two other stimulators of proliferation of TEC, bovine pituitary extract (BPE) and epidermal growth factor (EGF), did not stimulate zinc uptake by the TEC independent of proliferation. They have also shown, utilizing in-situ hybridization, that IL-1 and zinc induce metallothionein(MT) mRNA expression in human thymic epithelial cells. The exact role of metallothionein is not clear, but it is thought to be involved in regulation of trace metal metabolism, especially in maintenance of zinc homeostasis. Their current hypothesis is that IL-1 stimulates uptake of zinc into the TEC, followed by its complexing with metallothionein. Zinc is then thought to be transferred from metallothionein to thymulin. Immunostaining, utilizing an antithymulin antibody and a fluoresceinated goat anti-rabbit second antibody, confirms the presence of thymulin in TEC and its dependence on zinc. Upon stimulation, thymulin is then secreted. Known stimulants for thymulin include progesterone, dexamethasone, estradiol, testosterone, and prolactin. None of these secretagogues increase zinc uptake, suggesting the priming of the zinc-thymulin complex is unrelated to the regulation of its secretion.

Coto, J.A.; Hadden, J.W. (Univ. of South Florida, Tampa (United States))

1991-03-15

232

High Efficiency Multijunction Solar Cells with Finely-Tuned Quantum Wells  

NASA Astrophysics Data System (ADS)

The field of high efficiency (inorganic) photovoltaics (PV) is rapidly maturing in both efficiency goals and cover all cost reduction of fabrication. On one hand, know-how from space industry in new solar cell design configurations and on the other, fabrication cost reduction challenges for terrestrial uses of solar energy, have paved the way to a new generation of PV devices, capable of capturing most of the solar spectrum. For quite a while now, the goal of inorganic solar cell design has been the total (if possible) capture-absorption of the solar spectrum from a single solar cell, designed in such a way that a multiple of incident wavelengths could be simultaneously absorbed. Multi-absorption in device physics indicates parallel existence of different materials that absorb solar photons of different energies. Bulk solid state devices absorb at specific energy thresholds, depending on their respective energy gap (EG). More than one energy gaps would on principle offer new ways of photon absorption: if such a structure could be fabricated, two or more groups of photons could be absorbed simultaneously. The point became then what lattice-matched semiconductor materials could offer such multiple levels of absorption without much recombination losses. It was soon realized that such layer multiplicity combined with quantum size effects could lead to higher efficiency collection of photo-excited carriers. At the moment, the main reason that slows down quantum effect solar cell production is high fabrication cost, since it involves primarily expensive methods of multilayer growth. Existing multi-layer cells are fabricated in the bulk, with three (mostly) layers of lattice-matched and non-lattice-matched (pseudo-morphic) semiconductor materials (GaInP/InGaN etc), where photo-carrier collection occurs in the bulk of the base (coming from the emitter which lies right under the window layer). These carriers are given excess to conduction via tunnel junction (grown between at each interface and connecting the layers in series). This basic idea of a design has proven very successful in recent years, leading to solar cells of efficiency levels well above 30% (Fraunhofer Institute's multi-gap solar cell at 40.8%, and NREL's device at 40.2% respectively). Successful alloys have demonstrated high performance, such as InxGa1 - xP alloys (x (%) of gallium phosphide and (1 - x) (%) of indium phosphide). Other successful candidates, in current use and perpetual cell design consideration, are the lattice-matched GaAs/AlGaAs and InP/GaAs pairs or AlAs/GaAs/GaAs triple layers and alloys, which are heavily used in both solar and the electronics industry.

Varonides, Argyrios C.

233

Gallium phosphide energy converters  

NASA Technical Reports Server (NTRS)

Betavoltaic power supplies based on gallium phosphide can supply long term low-level power with high reliability. Results are presented for GaP devices powered by Ni-63 and tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/cm(exp 2) have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. A small demonstration system has been assembled that generates and stores enough electricity to light up an LED.

Sims, P. E.; DiNetta, Louis C.; DuganCavanagh, K.; Goetz, M. A.

1996-01-01

234

Donor-acceptor heterojunction solar cells based on perylene dimide and perylene bisbenzimidazole  

Microsoft Academic Search

We have fabricated heterojunction solar cells comprising active layers of perylene diimide (PDI) or perylene bisbenzimidazole (CONPER, conjugated perylene dye) as electron acceptor and ZnPC as donor. Bilayer solar cells were produced by successive evaporation of zinc phthalocyanine (ZnPC) and perylene diimide (PDI) or perylene bisbenzimidazole (CONPER) on glass substrates coated with indium doped tin oxide. Active layers with different

S. Erten; F. Meghdadi; S. Gunes; R. Koeppe; N. S. Sariciftci; S. Icli

2006-01-01

235

Epitaxial solar cells fabrication  

NASA Technical Reports Server (NTRS)

Silicon epitaxy has been studied for the fabrication of solar cell structures, with the intent of optimizing efficiency while maintaining suitability for space applications. SiH2CL2 yielded good quality layers and junctions with reproducible impurity profiles. Diode characteristics and lifetimes in the epitaxial layers were investigated as a function of epitaxial growth conditions and doping profile, as was the effect of substrates and epitaxial post-gettering on lifetime. The pyrolytic decomposition of SiH4 was also used in the epitaxial formation of highly doped junction layers on bulk Si wafers. The effects of junction layer thickness and bulk background doping level on cell performance, in particular, open-circuit voltage, were investigated. The most successful solar cells were fabricated with SiH2 CL2 to grow p/n layers on n(+) substrates. The best performance was obtained from a p(+)/p/n/n(+) structure grown with an exponential grade in the n-base layer.

Daiello, R. V.; Robinson, P. H.; Kressel, H.

1975-01-01

236

Solar cell module lamination process  

DOEpatents

A solar cell module lamination process using fluoropolymers to provide protection from adverse environmental conditions and thus enable more extended use of solar cells, particularly in space applications. A laminate of fluoropolymer material provides a hermetically sealed solar cell module structure that is flexible and very durable. The laminate is virtually chemically inert, highly transmissive in the visible spectrum, dimensionally stable at temperatures up to about 200.degree. C. highly abrasion resistant, and exhibits very little ultra-violet degradation.

Carey, Paul G. (Mountain View, CA); Thompson, Jesse B. (Brentwood, CA); Aceves, Randy C. (Tracy, CA)

2002-01-01

237

GRID-CONNECTED SOLAR ENERGY STORAGE USING THE ZINC-BROMINE FLOW BATTERY  

Microsoft Academic Search

The zinc-bromine battery is an emerging energy storage technology, ideally suited for solar load-shifting applications requiring 2 to 10 hours of energy storage. The energy density and cycle life of this advanced battery makes it attractive for applications where conventional lead-acid batteries face limitations due to size, weight, or cycle life. To test the viability of the zinc-bromine battery for

Benjamin L. Norris; Greg J. Ball; Peter Lex; Scaini Vince

238

Floating emitter solar cell  

NASA Technical Reports Server (NTRS)

A front surface contact floating emitter solar cell transistor is provided in a semiconductor body (n-type), in which floating emitter sections (p-type) are diffused or implanted in the front surface. Between the emitter sections, a further section is diffused or implanted in the front surface, but isolated from the floating emitter sections, for use either as a base contact to the n-type semiconductor body, in which case the section is doped n+, or as a collector for the adjacent emitter sections.

Chih, Sah (inventor); Cheng, Li-Jen (inventor)

1987-01-01

239

Cz bifacial solar cells  

SciTech Connect

High efficiencies have been achieved on bifacial solar cells made on FZ silicon. In the adaptation of the process to the more commonly used Cz material, attention has been paid to the influence of thermal processing on Cz, trying to avoid internal gettering effects related to oxygen precipitation. Lifetime measurements at different steps of the process have been carried out to quantify this influence. Reduction of thermal load by growth of a thin passivating oxide and deposition of a double antireflecting coating gives 17.7% when illuminate from the n{sup +} side 15.2% when illuminated from the p{sup +} one.

Canizo, C. del; Moehlecke, A.; Zanesco, I.; Luque, A.

2000-04-01

240

Monolithic tandem solar cell  

DOEpatents

A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surface of the InP substrate, (c) a second photoactive subcell on the first subcell; and (d) an optically transparent prismatic cover layer over the second subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched. 9 figs.

Wanlass, M.W.

1994-06-21

241

Photoelectric solar cell array  

SciTech Connect

A photoelectric solar cell device comprises a dispersing element exposed to the sun's radiation and followed in the optical path by photocells having different spectral sensitivities. Each photocell has its working surface so oriented that the light beam with the wavelength corresponding to the maximum spectral sensitivity of that photocell impinges on its working surface. The dispersing element is a hologram representing light sources with different wavelengths. The photocells are positioned in the image planes of the light sources producing the light beams of the corresponding wavelengths.

Lidorenko, N.S.; Afian, V.V.; Martirosian, R.G.; Ryabikov, S.V.; Strebkov, D.S.; Vartanian, A.V.

1983-11-29

242

Solar Energy Materials & Solar Cells 91 (2007) 13881391 Bifacial configurations for CdTe solar cells  

E-print Network

Solar Energy Materials & Solar Cells 91 (2007) 1388­1391 Bifacial configurations for CdTe solar cells A. Romeob,?, G. Khrypunovc , S. Galassinid , H. Zogga , A.N. Tiwaria,e a Thin Film Physics Group We present a different back contact for CdTe solar cell by the application of only a transparent

Romeo, Alessandro

243

Effect of dietary ligands and food matrices on zinc uptake in Caco-2 cells: implications in assessing zinc bioavailability.  

PubMed

The kinetics, depletion/repletion of zinc, and effects of dietary ligands/food matrices on (65)Zn uptake was studied in Caco-2 cells. The uptake of zinc showed a saturable and nonsaturable component, depending upon the media zinc concentrations. Intracellular depletion increased zinc uptake, whereas zinc loading did not. Phytic acid and histidine inhibited zinc uptake, while tannic acid, tartaric acid, arginine, and methionine increased zinc uptake. Tannic acid at a 1:50 molar ratio promoted zinc uptake from wheat- and rice-based food matrices. Further, Caco-2 cells responded similarly with zinc and iron uptake when fed Indian bread prepared from low- and high-extraction wheat flour, representing low and high phytate content. However, inclusion of tea extract or red grape juice as a source of polyphenols enhanced the uptake of zinc while decreasing that of iron. These results suggest that the Caco-2 cells predict the correct direction of response to dietary ligands even from complex foods. PMID:18947232

Sreenivasulu, Kilari; Raghu, Pullakhandam; Ravinder, Punjal; Nair, K Madhavan

2008-11-26

244

Solar Panel of Photovoltaic Cells  

USGS Multimedia Gallery

Solar panels or arrays of photovoltaic cells convert renewable solar radiation into electricity by a clean and environmentally sound means. Collected solar energy can either be used instantly or stored in batteries for later use. These systems can be used as a component of a larger photovoltaic syst...

245

High-efficiency GaAs and GaInP solar cells grown by all solid-state molecular-beam-epitaxy  

PubMed Central

We report the initial results of GaAs and GaInP solar cells grown by all solid-state molecular-beam-epitaxy (MBE) technique. For GaAs single-junction solar cell, with the application of AlInP as the window layer and GaInP as the back surface field layer, the photovoltaic conversion efficiency of 26% at one sun concentration and air mass 1.5 global (AM1.5G) is realized. The efficiency of 16.4% is also reached for GaInP solar cell. Our results demonstrate that the MBE-grown phosphide-contained III-V compound semiconductor solar cell can be quite comparable to the metal-organic-chemical-vapor-deposition-grown high-efficiency solar cell. PMID:22040124

2011-01-01

246

Schottky barrier solar cell  

NASA Technical Reports Server (NTRS)

A method of fabricating a Schottky barrier solar cell is described. The cell consists of a thin substrate of low cost material with at least the top surface of the substrate being electrically conductive. A thin layer of heavily doped n-type polycrystalling germanium is deposited on the substrate after a passivation layer is deposited to prevent migration of impurities into the polycrystalline germanium. The polycrystalline germanium is recrystallized to increase the crystal sizes to serve as a base layer on which a thin layer of gallium arsenide is vapor-epitaxilly grown followed by a thermally-grown oxide layer. A metal layer is deposited on the oxide layer and a grid electrode is deposited to be in electrical contact with the top surface of the metal layer.

Stirn, R. J.; Yeh, Y. C. M. (inventors)

1981-01-01

247

Transient fluctuations of intracellular zinc ions in cell proliferation  

SciTech Connect

Zinc is essential for cell proliferation, differentiation, and viability. When zinc becomes limited for cultured cells, DNA synthesis ceases and the cell cycle is arrested. The molecular mechanisms of actions of zinc are believed to involve changes in the availability of zinc(II) ions (Zn{sup 2+}). By employing a fluorescent Zn{sup 2+} probe, FluoZin-3 acetoxymethyl ester, intracellular Zn{sup 2+} concentrations were measured in undifferentiated and in nerve growth factor (NGF)-differentiated rat pheochromocytoma (PC12) cells. Intracellular Zn{sup 2+} concentrations are pico- to nanomolar in PC12 cells and are higher in the differentiated than in the undifferentiated cells. When following cellular Zn{sup 2+} concentrations for 48 h after the removal of serum, a condition that is known to cause cell cycle arrest, Zn{sup 2+} concentrations decrease after 30 min but, remarkably, increase after 1 h, and then decrease again to about one half of the initial concentration. Cell proliferation, measured by an MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, decreases after both serum starvation and zinc chelation. Two peaks of Zn{sup 2+} concentrations occur within one cell cycle: one early in the G1 phase and the other in the late G1/S phase. Thus, fluctuations of intracellular Zn{sup 2+} concentrations and established modulation of phosphorylation signaling, via an inhibition of protein tyrosine phosphatases at commensurately low Zn{sup 2+} concentrations, suggest a role for Zn{sup 2+} in the control of the cell cycle. Interventions targeted at these picomolar Zn{sup 2+} fluctuations may be a way of controlling cell growth in hyperplasia, neoplasia, and diseases associated with aberrant differentiation.

Li, Yuan [Division of Human Nutrition, Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, TX 77555 (United States)] [Division of Human Nutrition, Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, TX 77555 (United States); Maret, Wolfgang, E-mail: womaret@utmb.edu [Division of Human Nutrition, Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, TX 77555 (United States) [Division of Human Nutrition, Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, TX 77555 (United States); Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX 77555 (United States)

2009-08-15

248

Quantum junction solar cells.  

PubMed

Colloidal quantum dot solids combine convenient solution-processing with quantum size effect tuning, offering avenues to high-efficiency multijunction cells based on a single materials synthesis and processing platform. The highest-performing colloidal quantum dot rectifying devices reported to date have relied on a junction between a quantum-tuned absorber and a bulk material (e.g., TiO(2)); however, quantum tuning of the absorber then requires complete redesign of the bulk acceptor, compromising the benefits of facile quantum tuning. Here we report rectifying junctions constructed entirely using inherently band-aligned quantum-tuned materials. Realizing these quantum junction diodes relied upon the creation of an n-type quantum dot solid having a clean bandgap. We combine stable, chemically compatible, high-performance n-type and p-type materials to create the first quantum junction solar cells. We present a family of photovoltaic devices having widely tuned bandgaps of 0.6-1.6 eV that excel where conventional quantum-to-bulk devices fail to perform. Devices having optimal single-junction bandgaps exhibit certified AM1.5 solar power conversion efficiencies of 5.4%. Control over doping in quantum solids, and the successful integration of these materials to form stable quantum junctions, offers a powerful new degree of freedom to colloidal quantum dot optoelectronics. PMID:22881834

Tang, Jiang; Liu, Huan; Zhitomirsky, David; Hoogland, Sjoerd; Wang, Xihua; Furukawa, Melissa; Levina, Larissa; Sargent, Edward H

2012-09-12

249

Indium-free bottom electrodes for inverted organic solar cells with simplified cell architectures  

NASA Astrophysics Data System (ADS)

Inverted organic bulk heterojunction solar cells employing a multilayer electrode comprising of a thin Ag layer embedded between layers of zinc tin oxide (ZTO) are compared to cells using an indium tin oxide electrode. The In-free ZTO/Ag/ZTO (ZAZ) electrodes exhibit a favorable work function of 4.3 eV and are shown to allow for excellent electron extraction even without a further interlayer. As a result, issues like transient cell characteristics known from cells comprising titania can be readily avoided. This renders ZAZ a perfectly suited bottom electrode for inverted organic solar cells with a simplified cell architecture.

Schmidt, H.; Winkler, T.; Baumann, I.; Schmale, S.; Flgge, H.; Johannes, H.-H.; Hamwi, S.; Rabe, T.; Riedl, T.; Kowalsky, W.

2011-07-01

250

Methemoglobinemia in aluminum phosphide poisoning  

Microsoft Academic Search

Introduction. Acute aluminum phosphide (AlP) poisoning is one of the most common causes of acute pesticide poisoning in Iran. Hydrogen phosphide or phosphine gas is produced following reaction of AlP with water even at ambient humidity. Methemoglobinemia is a rare finding following phosphine poisoning. In this paper, two cases of fatal AlP poisoning complicated by methemoglobinemia are reported. Case Report.

Shahin Shadnia; Kambiz Soltaninejad; Hossein Hassan ian-Moghadam; Anahaita Sadeghi; Hormat Rahimzadeh; Nasim Zamani; Alireza Ghasemi-Toussi; Mohammad Abdollahi

2011-01-01

251

An algebraic model for a zinc/bromine flow cell  

E-print Network

AN ALGEBRAIC MODEL FOR A ZINC/BROMINE FLOW CELL A Thesis by GARY DON SIMPSON Submitted to the Graduate College of Texas A & M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1988 Major... Subject: Chemical Engineering AN ALGEBRAIC MODEL OF A ZINC/BROMINE FLOW CELL A Thesis GARY DON SIMPSON Approved as to style and content by: R. E. White (Chairman of Committee) A. T. Watson (Member) R. B. G (Member R. W. Flumerfelt (Head...

Simpson, Gary Don

1988-01-01

252

Lunar production of solar cells  

NASA Technical Reports Server (NTRS)

The feasibility of manufacturing of solar cells on the moon for spacecraft applications is examined. Because of the much lower escape velocity, there is a great advantage in lunar manufacture of solar cells compared to Earth manufacture. Silicon is abundant on the moon, and new refining methods allow it to be reduced and purified without extensive reliance on materials unavailable on the moon. Silicon and amorphous silicon solar cells could be manufactured on the moon for use in space. Concepts for the production of a baseline amorphous silicon cell are discussed, and specific power levels are calculated for cells designed for both lunar and Earth manufacture.

Landis, Geoffrey A.; Perino, Maria Antonietta

1989-01-01

253

Inversion layer MOS solar cells  

NASA Technical Reports Server (NTRS)

Inversion layer (IL) Metal Oxide Semiconductor (MOS) solar cells were fabricated. The fabrication technique and problems are discussed. A plan for modeling IL cells is presented. Future work in this area is addressed.

Ho, Fat Duen

1986-01-01

254

Stretchable polymer solar cell fibers.  

PubMed

Power yourself up: a sweater made from solar cells! Stretchable and wearable fibers are shown to be highly efficient polymer solar cells. Their stable energy conversion efficiency variation is below 10% even after 1000 bending cycles or stretching under a strain of 30%. These fibers can easily be woven into fabric from which any type of clothing can be made. PMID:25236579

Zhang, Zhitao; Yang, Zhibin; Deng, Jue; Zhang, Ye; Guan, Guozhen; Peng, Huisheng

2015-02-11

255

Supramolecular solar cells  

NASA Astrophysics Data System (ADS)

Supramolecular chemistry - chemistry of non-covalent bonds including different type of intermolecular interactions viz., ion-pairing, ion-dipole, dipole-dipole, hydrogen bonding, cation-pi and Van der Waals forces. Applications based on supramolecular concepts for developing catalysts, molecular wires, rectifiers, photochemical sensors have been evolved during recent years. Mimicking natural photosynthesis to build energy harvesting devices has become important for generating energy and solar fuels that could be stored for future use. In this dissertation, supramolecular chemistry is being explored for creating light energy harvesting devices. Photosensitization of semiconductor metal oxide nanoparticles, such as titanium dioxide (TiO2) and tin oxide (SnO2,), via host-guest binding approach has been explored. In the first part, self-assembly of different porphyrin macrocyclic compounds on TiO2 layer using axial coordination approach is explored. Supramolecular dye sensitized solar cells built based on this approach exhibited Incident Photon Conversion Efficiency (IPCE) of 36% for a porphyrin-ferrocene dyad. In the second part, surface modification of SnO2 with water soluble porphyrins and phthalocyanine resulted in successful self-assembly of dimers on SnO2 surface. IPCE more than 50% from 400 - 700 nm is achieved for the supramolecular self-assembled heterodimer photocells is achieved. In summary, the axial ligation and ion-pairing method used as supramolecular tools to build photocells, exhibited highest quantum efficiency of light energy conversion with panchromatic spectral coverage. The reported findings could be applied to create interacting molecular systems for next generation of efficient solar energy harvesting devices.

Subbaiyan, Navaneetha Krishnan

256

The challenges of organic polymer solar cells  

E-print Network

The technical and commercial prospects of polymer solar cells were evaluated. Polymer solar cells are an attractive approach to fabricate and deploy roll-to-roll processed solar cells that are reasonably efficient (total ...

Saif Addin, Burhan K. (Burhan Khalid)

2011-01-01

257

GaAs Solar Cell Radiation Handbook  

NASA Technical Reports Server (NTRS)

History of GaAs solar cell development is provided. Photovoltaic equations are described along with instrumentation techniques for measuring solar cells. Radiation effects in solar cells, electrical performance, and spacecraft flight data for solar cells are discussed. The space radiation environment and solar array degradation calculations are addressed.

Anspaugh, B. E.

1996-01-01

258

Germanium Nanocrystal Solar Cells  

NASA Astrophysics Data System (ADS)

Greenhouse gas concentrations in the atmosphere are approaching historically unprecedented levels from burning fossil fuels to meet the ever-increasing world energy demand. A rapid transition to clean energy sources is necessary to avoid the potentially catastrophic consequences of global warming. The sun provides more than enough energy to power the world, and solar cells that convert sunlight to electricity are commercially available. However, the high cost and low efficiency of current solar cells prevent their widespread implementation, and grid parity is not anticipated to be reached for at least 15 years without breakthrough technologies. Semiconductor nanocrystals (NCs) show promise for cheap multi-junction photovoltaic devices. To compete with photovoltaic materials that are currently commercially available, NCs need to be inexpensively cast into dense thin films with bulk-like electrical mobilities and absorption spectra that can be tuned by altering the NC size. The Group II-VI and IV-VI NC communities have had some success in achieving this goal by drying and then chemically treating colloidal particles, but the more abundant and less toxic Group IV NCs have proven more challenging. This thesis reports thin films of plasma-synthesized Ge NCs deposited using three different techniques, and preliminary solar cells based on these films. Germanium tetrachloride is dissociated in the presence of hydrogen in a nonthermal plasma to nucleate Ge NCs. Transmission electron microscopy and X-ray diffraction indicate that the particles are nearly monodisperse (standard deviations of 10-15% the mean particle diameter) and the mean diameter can be tuned from 4-15 nm by changing the residence time of the Ge NCs in the plasma. In the first deposition scheme, a Ge NC colloid is formed by reacting nanocrystalline powder with 1-dodecene and dispersing the functionalized NCs in a solvent. Films are then formed on substrates by drop-casting the colloid and allowing it to dry. As-deposited films are electrically insulating due to the long hydrocarbon molecules separating neighboring particles; however, mass spectrometry shows that annealing treatments successfully decompose these molecules. After annealing at 250 C, Ge NC films exhibit conductivities as large as 10-6 S/cm. In the second film deposition scheme, a Ge NC colloid is formed by dispersing Ge NCs in select solvents without further surface modification. While these "bare" NCs quickly agglomerate and flocculate in nearly all non-polar solvents, they remain stable in benzonitrile and 1,2-dichlorobenzene, among others. Thin-film field-effect transistors have been fabricated by spinning Ge NC colloids onto substrates and the films have been subjected to various annealing procedures. The devices show n-type, p -type, or ambipolar behavior depending on the annealing conditions, with Ge NC films annealed at 300C exhibiting electron saturation mobilities greater than 10-2 cm2/Vs and on-to-off ratios of 104. The final film deposition scheme involves the impaction of Ge NCs onto substrates downstream of the synthesis plasma via acceleration of the NCs through an orifice. This technique produces highly uniform films with densities greater than 50% of the density of bulk Ge. By varying the size of the Ge NCs, we have measured films with band gaps ranging from the bulk value of 0.7 eV to over 1.1 eV for films of 4 nm Ge NCs. Having deposited dense thin films with tunable band gaps and respectable mobilities, we have begun fabricating bilayer solar cells consisting of heterojunctions between Ge NC films and P3HT, Si NCs, or Si wafers. Preliminary devices exhibit opencircuit voltages and short-circuit currents as large as 0.3 V and 4 mA/cm 2, respectively.

Holman, Zachary Charles

259

Upconversion in solar cells  

PubMed Central

The possibility to tune chemical and physical properties in nanosized materials has a strong impact on a variety of technologies, including photovoltaics. One of the prominent research areas of nanomaterials for photovoltaics involves spectral conversion. Modification of the spectrum requires down- and/or upconversion or downshifting of the spectrum, meaning that the energy of photons is modified to either lower (down) or higher (up) energy. Nanostructures such as quantum dots, luminescent dye molecules, and lanthanide-doped glasses are capable of absorbing photons at a certain wavelength and emitting photons at a different (shorter or longer) wavelength. We will discuss upconversion by lanthanide compounds in various host materials and will further demonstrate upconversion to work for thin-film silicon solar cells. PMID:23413889

2013-01-01

260

Core-Shell Nanopillar Array Solar Cells using Cadmium Sulfide Coating on Indium Phosphide Nanopillars  

E-print Network

J. Herrero, Chemical Bath Deposition of CdS Thin Films?: Anis formed by chemical bath deposition of CdS which providesCdS thin film layers grown by close-spaced sublimation and chemical bath deposition,

Tu, Bor-An Clayton

2013-01-01

261

solar cells employing scalable low-cost antireflective coating  

NASA Astrophysics Data System (ADS)

In this study, a non-selenized CuInGaSe2 (CIGS) solar device with textured zinc oxide (ZnO) antireflection coatings was studied. The ZnO nanostructure was fabricated by a low-temperature aqueous solution deposition method. With controlling the morphology of the solution-grown tapered ZnO nanorod coatings, the average reflectance of the CIGS solar device decreased from 8.6% to 2.1%, and the energy conversion efficiency increased from 9.1% to 11.1%. The performance improvement in the CuInGaSe2 thin-film solar cell was well explained due to the gradual increase of the refractive index between air and the top electrode of solar cell device by the insertion of the ZnO nanostructure. The results demonstrate a potential application of the ZnO nanostructure array for efficient solar device technology.

Jheng, Bao-Tang; Liu, Po-Tsun; Wu, Meng-Chyi

2014-07-01

262

New Materials for Chalcogenide Based Solar Cells  

NASA Astrophysics Data System (ADS)

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

Tosun, Banu Selin

263

Solar Energy Materials & Solar Cells 90 (2006) 664677 Invited article  

E-print Network

Solar Energy Materials & Solar Cells 90 (2006) 664­677 Invited article Recent developments in evaporated CdTe solar cells G. Khrypunova , A. Romeob , F. Kurdesauc , D.L. Ba¨ tznerd , H. Zogge , A Abstract Recent developments in the technology of high vacuum evaporated CdTe solar cells are reviewed

Romeo, Alessandro

264

Multiple Exciton Generation Solar Cells  

SciTech Connect

Heat loss is the major factor limiting traditional single junction solar cells to a theoretical efficiency of 32%. Multiple Exciton Generation (MEG) enables efficient use of the solar spectrum yielding a theoretical power conversion efficiency of 44% in solar cells under 1-sun conditions. Quantum-confined semiconductors have demonstrated the ability to generate multiple carriers but present-day materials deliver efficiencies far below the SQ limit of 32%. Semiconductor quantum dots of PbSe and PbS provide an active testbed for developing high-efficiency, inexpensive solar cells benefitting from quantum confinement effects. Here, we will present recent work of solar cells employing MEG to yield external quantum efficiencies exceeding 100%.

Luther, J. M.; Semonin, O. E.; Beard, M. C.; Gao, J.; Nozik, A. J.

2012-01-01

265

Targeted chromosomal deletions in human cells using zinc finger nucleases  

Microsoft Academic Search

We present a novel approach for generating targeted deletions of genomic segments in human and other eukaryotic cells using engineered zinc finger nucleases (ZFNs). We found that ZFNs designed to target two different sites in a human chromosome could introduce two concurrent DNA double-strand breaks (DSBs) in the chromosome and give rise to targeted deletions of the genomic segment between

Hyung Joo Lee; Eunji Kim; Jin-Soo Kim

2010-01-01

266

Fabrication and testing of large size nickel-zinc cells  

NASA Technical Reports Server (NTRS)

The design and construction of nickel zinc cells, containing sintered nickel electrodes and asbestos coated inorganic separator materials, were outlined. Negative electrodes were prepared by a dry pressing process while various inter-separators were utilized on the positive electrodes, consisting of non-woven nylon, non-woven polypropylene, and asbestos.

Klein, M.

1977-01-01

267

Solar electron source and thermionic solar cell  

NASA Astrophysics Data System (ADS)

Common solar technologies are either photovoltaic/thermophotovoltaic, or use indirect methods of electricity generation such as boiling water for a steam turbine. Thermionic energy conversion based on the emission of electrons from a hot cathode into vacuum and their collection by an anode is also a promising route. However, thermionic solar conversion is extremely challenging as the sunlight intensity is too low for heating a conventional cathode to thermionic emission temperatures in a practical manner. Therefore, compared to other technologies, little has been done in this area, and the devices have been mainly limited to large experimental apparatus investigated for space power applications. Based on a recently observed "Heat Trap" effect in carbon nanotube arrays, allowing their efficient heating with low-power light, we report the first compact thermionic solar cell. Even using a simple off-the-shelf focusing lens, the device delivered over 1 V across a load. The device also shows intrinsic storage capacity.

Yaghoobi, Parham; Vahdani Moghaddam, Mehran; Nojeh, Alireza

2012-12-01

268

Heteroepitaxial InP, and ultrathin, directly glassed, GaAs 3-5 solar cells  

NASA Astrophysics Data System (ADS)

The commercial application of Indium Phosphide solar cells in practical space missions is crucially dependent upon achieving a major cost reduction which could be offered by heteroepitaxy on cheaper, more rugged substrates. Furthermore, significant mass reduction, compatibility with mechanically stacked multijunction cells, and elimination of the current loss through glue discoloration, is possible in III-V solar cells by the development of ultrathin, directly glassed cells. The progress of a UK collaborative program to develop high efficiency, homojunction InP solar cells, grown by MOCVD on Si substrates, is described. Results of homoepitaxial cells (is greater than 17 percent 1 Sun AM0) are presented, together with progress in achieving low dislocation density heteroepitaxy. Also, progress in a UK program to develop ultrathin directly-glassed GaAs cells is described. Ultrathin (5 micron) GaAs cells, with 1 Sun AM0 efficiencies up to 19.1 percent, are presented, together with progress in achieving a direct (adhesive-less) bond between the cell and coverglass. Consequential development to, for example, cell grids, are also discussed.

Hardingham, C. M.; Cross, T. A.

1993-05-01

269

Heteroepitaxial InP, and ultrathin, directly glassed, GaAs 3-5 solar cells  

NASA Technical Reports Server (NTRS)

The commercial application of Indium Phosphide solar cells in practical space missions is crucially dependent upon achieving a major cost reduction which could be offered by heteroepitaxy on cheaper, more rugged substrates. Furthermore, significant mass reduction, compatibility with mechanically stacked multijunction cells, and elimination of the current loss through glue discoloration, is possible in III-V solar cells by the development of ultrathin, directly glassed cells. The progress of a UK collaborative program to develop high efficiency, homojunction InP solar cells, grown by MOCVD on Si substrates, is described. Results of homoepitaxial cells (is greater than 17 percent 1 Sun AM0) are presented, together with progress in achieving low dislocation density heteroepitaxy. Also, progress in a UK program to develop ultrathin directly-glassed GaAs cells is described. Ultrathin (5 micron) GaAs cells, with 1 Sun AM0 efficiencies up to 19.1 percent, are presented, together with progress in achieving a direct (adhesive-less) bond between the cell and coverglass. Consequential development to, for example, cell grids, are also discussed.

Hardingham, C. M.; Cross, T. A.

1993-01-01

270

Life cycle assessment of the conventional and solar thermal production of zinc and synthesis gas  

Microsoft Academic Search

The current industrial productions of zinc and synthesis gas are characterized by their high energy consumption and their concomitant environmental pollution. Emissions of greenhouse gases (GHG) could be reduced substantially by combining both productions and by replacing fossil fuels with concentrated solar energy as the source of high-temperature process heat. The extent of such a GHG mitigation has been quantified

Miriam Werder; Aldo Steinfeld

2000-01-01

271

InGaP Heterojunction Barrier Solar Cells  

NASA Technical Reports Server (NTRS)

A new solar-cell structure utilizes a single, ultra-wide well of either gallium arsenide (GaAs) or indium-gallium-phosphide (InGaP) in the depletion region of a wide bandgap matrix, instead of the usual multiple quantum well layers. These InGaP barrier layers are effective at reducing diode dark current, and photogenerated carrier escape is maximized by the proper design of the electric field and barrier profile. With the new material, open-circuit voltage enhancements of 40 and 100 mV (versus PIN control systems) are possible without any degradation in short-circuit current. Basic tenets of quantum-well and quantum- dot solar cells are utilized, but instead of using multiple thin layers, a single wide well works better. InGaP is used as a barrier material, which increases open current, while simultaneously lowering dark current, reducing both hole diffusion from the base, and space charge recombination within the depletion region. Both the built-in field and the barrier profile are tailored to enhance thermionic emissions, which maximizes the photocurrent at forward bias, with a demonstrated voltage increase. An InGaP heterojunction barrier solar cell consists of a single, ultra-wide GaAs, aluminum-gallium-arsenide (AlGaAs), or lower-energy-gap InGaP absorber well placed within the depletion region of an otherwise wide bandgap PIN diode. Photogenerated electron collection is unencumbered in this structure. InGaAs wells can be added to the thick GaAs absorber layer to capture lower-energy photons.

Welser, Roger E.

2010-01-01

272

Module level solutions to solar cell polarization  

DOEpatents

A solar cell module includes interconnected solar cells, a transparent cover over the front sides of the solar cells, and a backsheet on the backsides of the solar cells. The solar cell module includes an electrical insulator between the transparent cover and the front sides of the solar cells. An encapsulant protectively packages the solar cells. To prevent polarization, the insulator has resistance suitable to prevent charge from leaking from the front sides of the solar cells to other portions of the solar cell module by way of the transparent cover. The insulator may be attached (e.g., by coating) directly on an underside of the transparent cover or be a separate layer formed between layers of the encapsulant. The solar cells may be back junction solar cells.

Xavier, Grace (Fremont, CA), Li; Bo (San Jose, CA)

2012-05-29

273

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

274

Zn3P2 and Cu2O Substrates for Solar Energy Conversion  

NASA Astrophysics Data System (ADS)

Zinc phosphide (Zn3P2) and cuprous oxide (Cu 2O) are promising and earth-abundant alternatives to traditional thin film photovoltaics materials such as CIGS, CdTe, and a-Si. We have prepared high purity substrates of Zn3P2 from elemental zinc and phosphorus, and Cu2O by the thermal oxidation of copper foils, to investigate their fundamental material properties and potential for solar energy conversion. Photoluminescence-based measurements of Zn3P2 substrates have revealed a fundamental indirect band gap at 1.38 eV and a direct band gap at 1.50 eV, with time-resolved data indicating minority carrier diffusion lengths of ?7 ?m. Solar cells based on Mg/Zn3P2 junctions with solar energy conversion efficiency reaching 4.5% were examined by composition profiling to elucidate the passivation reaction between Mg metal and Zn3P2 surfaces. Semiconductor/liquid junctions incorporating Cu2O substrates exhibited open-circuit voltage, Voc, values in excess of 800 mV and internal quantum yields approaching 100% in the 400-500 nm spectral range.

Kimball, Gregory Michael

275

DECREASED INTRACELLULAR ZINC IN HUMAN TUMORIGENIC PROSTATE EPITHELIAL CELLS: A POSSIBLE ROLE IN PROSTATE CANCER PROGRESSION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Zinc plays important roles in maintaining normal function of the prostate and in tumorigenesis of prostate epithelia. Evidence has shown that prostate malignant epithelial cells contain much less cellular zinc than the surrounding normal epithelial cells. We characterized the zinc homeostatic featur...

276

Stray thermal influences in zinc fixed-point cells  

NASA Astrophysics Data System (ADS)

The influence of thermal effects is a major uncertainty contribution to the calibration of Standard Platinum Resistance Thermometers (SPRTs) in fixed-point cells. Axial heat losses strongly depend on the fixed-point temperature, constructional details of cells and SPRTs and the resulting heat transfer between cell, thermometer, furnace and environment. At the zinc point contributions by heat conduction and thermal radiation must be considered. Although the measurement of temperature gradients in the re-entrant well of a fixed-point cell provides very important information about the influence of axial heat losses, further investigations are required for a reliable estimate of the resulting uncertainty contribution. It is shown that specific modifications of a zinc fixed-point cell, following generally accepted principles, may result in systematic deviations of the measured fixed-point temperatures larger than typically stated in the uncertainty budget of National Metrology Institutes (NMIs). The underlying heat transport processes are investigated and the consequences for the construction of zinc cells are discussed.

Rudtsch, S.; Aulich, A.; Monte, C.

2013-09-01

277

Stray thermal influences in zinc fixed-point cells  

SciTech Connect

The influence of thermal effects is a major uncertainty contribution to the calibration of Standard Platinum Resistance Thermometers (SPRTs) in fixed-point cells. Axial heat losses strongly depend on the fixed-point temperature, constructional details of cells and SPRTs and the resulting heat transfer between cell, thermometer, furnace and environment. At the zinc point contributions by heat conduction and thermal radiation must be considered. Although the measurement of temperature gradients in the re-entrant well of a fixed-point cell provides very important information about the influence of axial heat losses, further investigations are required for a reliable estimate of the resulting uncertainty contribution. It is shown that specific modifications of a zinc fixed-point cell, following generally accepted principles, may result in systematic deviations of the measured fixed-point temperatures larger than typically stated in the uncertainty budget of National Metrology Institutes (NMIs). The underlying heat transport processes are investigated and the consequences for the construction of zinc cells are discussed.

Rudtsch, S.; Aulich, A.; Monte, C. [Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin (Germany)] [Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin (Germany)

2013-09-11

278

Nanostructured phosphides as photoelectrode materials for artificial photosynthesis  

NASA Astrophysics Data System (ADS)

In this work we describe present experimental results for two related ternary phosphide materials, N-alloyed GaP and ZnGeP2. These materials represent two potential mid-bandgap photoelectrode materials for artificial photosynthetic systems for solar energy conversion/storage. For photoelectrochemical cells designed to generate energyrich chemical fuels under illumination, candidate photoelectrode materials should demonstrate the capacity to sustain large photovoltages and photocurrent densities under solar insolation. The results in this work show that the optical properties of these two materials should enable the possibilities for light collection out past 600 nm. For N-alloyed GaP nanowire films, diffuse reflectance spectra show the increase of light absorption at sub-bandgap wavelengths with increasing NH3(g) used during the annealing step. Corresponding photoelectrochemical data show that the quantum efficiency for light collection at sub-bandgap wavelengths does not follow the same monotonic trend. Separately, we report the first demonstration of ZnGeP2 nanowire films. The as-prepared materials show reflectance responses consistent with a mid-bandgap material featuring a pseudo-direct bandgap.

Wen, Wen; Collins, Sean M.; Maldonado, Stephen

2011-10-01

279

Solar cells: A solid compromise  

NASA Astrophysics Data System (ADS)

Efficiency of power conversion and thermal stability usually don't go together in dye-sensitized solar cells. Now a novel combination of an amphiphilic dye and a polymer gel electrolyte features both these important properties.

Durrant, James R.; Haque, Saif A.

2003-06-01

280

Long-term temperature effects on GaAs solar cells  

NASA Technical Reports Server (NTRS)

The thermal degradation of AlGaAs solar cells resulting from a long-term operation in a space environment is investigated. The solar cell degradation effects caused by zinc and aluminum diffusion as well as deterioration by arsenic evaporation are presented. Also, the results are presented of experimental testing and measurements of various GaAs solar cell properties while the solar cell was operating in the temperature range of 27 C to 350 C. In particular, the properties of light current voltage curves, dark current voltage curves, and spectral response characteristics are given. Finally, some theoretical models for the annealing of radiation damage over various times and temperatures are included.

Heinbockel, J. H.; Hong, K. H.

1979-01-01

281

Radiation effects in solar cells  

NASA Astrophysics Data System (ADS)

Two types of space solar cells, silicon single-junction and InGaP/GaAs/Ge triple-junction (3J) solar cells, have been primarily adopted for spacecraft. The conversion efficiencies of the solar cells under AM0, 1 sun condition are ~17% for silicon and ~30% for 3J cells. Radiation degradation occurs in space due to high-energy electrons and protons existing in space environment. The degradation is caused by radiation induced crystal defects which act as minority-carrier recombination centers and majority-carrier trap centers. The 3J cells are superior radiation resistant to the silicon cells, and this is mainly because the InGaP top-subcell has property of very high radiation resistance.

Imaizumi, Mitsuru; Ohshima, Takeshi

2013-05-01

282

CCMR: Nanocrystal Sensitized Solar Cells  

NSDL National Science Digital Library

Nanocrystal sensitized solar cells demonstrate a possible cheap solution to practical device manufacture. This research examined the feasibility of using lead sulfide nanocrystals to sensitize tin dioxide and titanium dioxide substrates for the purpose of making a functioning photovoltaic device. Challenges included optimizing the substrate materials as well as the thin films made from them. Results indicate that titanium dioxide produces more suitable thin films than tin dioxide. Also, the methods employed did produce a functioning solar cell after optimization.

Perry, Alexis

2009-08-15

283

Terrestrial concentrator solar cell module  

SciTech Connect

This patent describes a solar cell module having a plurality of discrete cell units wherein each cell unit constitutes a tandem cell comprising an upper cell of a first semiconductive material and a lower cell of a second semiconductive material. It comprises a housing having a base and an upper portion; primary outer lens elements supported by the housing upper portion; a secondary radiant energy concentrating element associated with each primary lens element for protecting the carrier tape against incident light; each of the solar cell units being thermally coupled to the base; and parallel spaced strips of conductive material carried by the tape with means for separately connecting the strips to predetermined contact surfaces of the upper and lower cells of each cell unit.

Fraas, L.M.; Mansoori, N.; Kim, N.B.; Avery, J.E.

1992-06-02

284

Dust removal from solar cells  

NASA Technical Reports Server (NTRS)

A solar panel cleaning device includes a solar panel having a plurality of photovoltaic cells arranged in rows and embedded in the solar panel with space between the rows. A transparent dielectric overlay is affixed to the solar panel. A plurality of electrode pairs each of which includes an upper and a lower electrode are arranged on opposite sides of the transparent dielectric and are affixed thereto. The electrodes may be transparent electrodes which may be arranged without concern for blocking sunlight to the solar panel. The solar panel may be a dielectric and its dielectric properties may be continuously and spatially variable. Alternatively the dielectric used may have dielectric segments which produce different electrical field and which affects the wind "generated."

Ashpis, David E. (Inventor)

2011-01-01

285

Managing aluminum phosphide poisonings.  

PubMed

Aluminum phosphide (AlP) is a cheap, effective and commonly used pesticide. However, unfortunately, it is now one of the most common causes of poisoning among agricultural pesticides. It liberates lethal phosphine gas when it comes in contact either with atmospheric moisture or with hydrochloric acid in the stomach. The mechanism of toxicity includes cellular hypoxia due to the effect on mitochondria, inhibition of cytochrome C oxidase and formation of highly reactive hydroxyl radicals. The signs and symptoms are nonspecific and instantaneous. The toxicity of AlP particularly affects the cardiac and vascular tissues, which manifest as profound and refractory hypotension, congestive heart failure and electrocardiographic abnormalities. The diagnosis of AlP usually depends on clinical suspicion or history, but can be made easily by the simple silver nitrate test on gastric content or on breath. Due to no known specific antidote, management remains primarily supportive care. Early arrival, resuscitation, diagnosis, decrease the exposure of poison (by gastric lavage with KMnO(4), coconut oil), intensive monitoring and supportive therapy may result in good outcome. Prompt and adequate cardiovascular support is important and core in the management to attain adequate tissue perfusion, oxygenation and physiologic metabolic milieu compatible with life until the tissue poison levels are reduced and spontaneous circulation is restored. In most of the studies, poor prognostic factors were presence of acidosis and shock. The overall outcome improved in the last decade due to better and advanced intensive care management. PMID:21887030

Gurjar, Mohan; Baronia, Arvind K; Azim, Afzal; Sharma, Kalpana

2011-07-01

286

NREL Spurred the Success of Multijunction Solar Cells (Fact Sheet)  

SciTech Connect

Many scientists once believed that high-quality gallium indium phosphide (GaInP) alloys could not be grown for use as semiconductors because the alloys would separate. However, researchers at the National Renewable Energy Laboratory (NREL) thought differently, and they employed GaInP in a material combination that allowed the multijunction cell to flourish. The multijunction cell is now the workhorse that powers satellites and the catalyst for renewed interest in concentrator photovoltaic products.

Not Available

2013-08-01

287

Transparent conductive oxides for thin-film silicon solar cells  

NASA Astrophysics Data System (ADS)

This thesis describes research on thin-film silicon solar cells with focus on the transparent conductive oxide (TCO) for such devices. In addition to the formation of a transparent and electrically conductive front electrode for the solar cell allowing photocurrent collection with low ohmic losses, the front TCO plays an important role for the light enhancement of thin-film silicon pin type solar cells. If the TCO is rough, light scattering at rough interfaces in the solar cell in combination with a highly reflective back contact leads to an increase in optical path length of the light. Multiple (total) internal reflectance leads to virtual 'trapping' of the light in the solar cell structure, allowing a further decrease in absorber thickness and thus thin-film silicon solar cell devices with higher and more stable efficiency. Here, the optical mechanisms involved in the light trapping in thin-film silicon solar cells have been studied, and two types of front TCO materials have been investigated with respect to their suitability as front TCO in thin-film silicon pin type solar cells. Undoped and aluminum doped zinc oxide layers have been fabricated for the first time by the expanding thermal plasma chemical vapour deposition (ETP CVD) technique at substrate temperatures between 150 C and 350 C, and successfully implemented as a front electrode material for amorphous silicon pin superstrate type solar cells. Solar cells with efficiencies comparable to cells on Asahi U-type reference TCO have been reproducibly obtained. A higher haze is needed for the ZnO samples studied here than for Asahi U-type TCO in order to achieve comparable long wavelength response of the solar cells. This is attributed to the different angular distribution of the scattered light, showing higher scattering intensities at large angles for the Asahi U-type TCO. A barrier at the TCO/p interface and minor collection problems may explain the slightly lower fill factors obtained for the cells on ETP ZnO. The solar cells deposited on the first doped ZnO:Al layers suffered from collection problems reducing the fill factor, and from shunting. This is attributed to the steep trenches, sharp features and vertical steps that have been identified at the TCO surface. ZnO:Al layers with granular structure, deposited at higher argon flow through the cascaded arc plasma source, allowed for fill factors of the solar cells up to 0.70, comparable to cells on undoped ZnO. The best solar cell on doped ZnO:Al deposited by ETP CVD achieved an efficiency of 9.3 % which is comparable to the 9.4 % obtained on Asahi U-type SnO2:F. Fluorinated tin oxide has been deposited by Atmospheric Chemical Vapor Deposition (APCVD) on glass from three different tin precursors, tetramethyltin, monobutyltin trichloride, and tin tetrachloride (TTC). TTC is the Sn precursor which resulted in the TCO with the best performance of a-Si:H pin solar cells. In accordance with the conclusions from our experiments with solar cells on undoped and aluminum doped zinc oxide, a high surface roughness and haze do not necessarily lead to a lower diode quality, and vice versa.

Lffler, J.

2005-04-01

288

Transparent electrode requirements for thin film solar cell modules Michael W. Rowell and Michael D. McGehee*  

E-print Network

transparent conducting oxides (TCO),2 such as indium tin oxide (ITO) or doped zinc oxide (ZnO), are used owingTransparent electrode requirements for thin film solar cell modules Michael W. Rowell and Michael D The transparent conductor (TC) layer in thin film solar cell modules has a significant impact on the power

McGehee, Michael

289

EE580 Solar Cells Todd J. Kaiser  

E-print Network

7/21/2010 1 EE580 ­ Solar Cells Todd J. Kaiser · Lecture 09 · Photovoltaic Systems 1Montana State University: Solar Cells Lecture 9: PV Systems 11 Solar heating (70-90%) is more efficient than photovoltaic (15%-20%) but electricity generally is more useful than heat. Solar Cell Basics · Photovoltaic Systems

Kaiser, Todd J.

290

Induction of zinc transporters by forskolin in human trophoblast BeWo cells  

Microsoft Academic Search

During pregnancy, the zinc level in fetal serum is up to two-fold higher than that in the maternal serum at the end of pregnancy, but the mechanism of zinc release from the placenta into fetal circulation is not well understood. In this study, we determined the expression profiles of zinc transporters in human trophoblast BeWo cells, a representative human trophoblast

Nagayoshi Asano; Masuo Kondoh; Chiaki Ebihara; Makiko Fujii; Tsuyoshi Nakanishi; Naoki Utoguchi; Shuichi Enomoto; Keiichi Tanaka; Yoshiteru Watanabe

2006-01-01

291

Estimation of minority carrier diffusion lengths in InP/GaAs solar cells  

NASA Technical Reports Server (NTRS)

Minority carrier diffusion length is one of the most important parameters affecting the solar cell performance. An attempt is made to estimate the minority carrier diffusion lengths is the emitter and base of InP/GaAs heteroepitaxial solar cells. The PC-1D computer model was used to simulate the experimental cell results measured at NASA Lewis under AMO (air mass zero) spectrum at 25 C. A 16 nm hole diffusion length in the emitter and a 0.42 micron electron diffusion length in the base gave very good agreement with the I-V curve. The effect of varying minority carrier diffusion lengths on cell short current, open circuit voltage, and efficiency was studied. It is also observed that the front surface recombination velocity has very little influence on the cell performance. The poor output of heteroepitaxial cells is caused primarily by the large number of dislocations generated at the interfaces that propagate through the bulk indium phosphide layers. Cell efficiency as a function of dislocation density was calculated and the effect of improved emitter bulk properties on cell efficiency is presented. It is found that cells with over 16 percent efficiencies should be possible, provided the dislocation density is below 10(exp 6)/sq cm.

Jain, R. K.; Flood, D. J.

1990-01-01

292

Zinc and its transporters, pancreatic beta cells, and insulin metabolism  

Technology Transfer Automated Retrieval System (TEKTRAN)

Zinc is an essential trace metal for life. Two families of zinc transporters, SLC30A (ZnT) and SLC39A (ZIP) are required for maintaining cellular zinc homeostasis. ZnTs function to decrease cytoplasmic zinc concentrations whereas ZIPs do the opposite. Expression of zinc transporters can be tissue/ce...

293

Wraparound-contact solar cells  

NASA Technical Reports Server (NTRS)

Positive and negative electrical contacts are on back surface of wraparound-contact solar cell. With both terminals on nonilluminated side, cells can be connected back-to-back, and interconnection of many cells can be automated by using printed-circuit techniques. Cells are made by screen-printing layer of dielectric around edge of cell and extending top contact over dielectric to back surface. Wraparound also facilitates application of transparent covers and encapsulants. Efficiencies of cells are in excess of seventeen percent.

Baraona, C. R.; Klucher, T. M.; Thornhill, J. W.; Scott-Monck, J.

1979-01-01

294

Silicon concentrator solar cell research  

SciTech Connect

This report describes work conducted between December 1990 and May 1992 continuing research on silicon concentrator solar cells. The objectives of the work were to improve the performance of high-efficiency cells upon p-type substrates, to investigate the ultraviolet stability of such cells, to develop concentrator cells based on n-type substrates, and to transfer technology to appropriate commercial environments. Key results include the identification of contact resistance between boron-defused areas and rear aluminum as the source of anomalously large series resistance in both p- and n-type cells. A major achievement of the present project was the successful transfer of cell technology to both Applied Solar Energy Corporation and Solarex Corporation.

Green, M.A.; Zhao, J.; Wang, A.; Dai, X.; Milne, A.; Cai, S.; Aberle, A.; Wenham, S.R. [Univ. of New South Wales, Kensington, NSW (AU). Centre for Photovoltaic Devices and Systems

1993-06-01

295

Zinc transporter 5 and zinc transporter 7 induced by high glucose protects peritoneal mesothelial cells from undergoing apoptosis.  

PubMed

Zinc is an essential micronutrient and cytoprotectant involved in many types of apoptosis. The zinc transporter family SLC30A (ZnTs) is an important factor in the regulation of zinc homeostasis; however, its function in apoptosis in peritoneal mesothelial cells (PMCs) remains unknown. This study explores the regulation of zinc transporters and how they play a role in cell survival, particularly in rat peritoneal mesothelial cells (RPMCs), surrounding glucose concentrations, and the molecular mechanism involved. The messenger RNA (mRNA) transcripts were quantitatively measured by real-time polymerase chain reaction for all known nine zinc transport exporters (SLC30A1-8,10), as well as in primary RPMCs and the cells cultured under nonstimulated and HG-stimulated conditions. While many zinc transporters were constitutively expressed, ZnT5 mRNA and ZnT7 mRNA were strongly induced by HG. Overexpression of ZnT5 and ZnT7 respectively resulted in a decrease in the expression of caspace 3, caspace 8, BAX, and AIF and coincided with cell survival in the presence of HG. Inhibition of ZnT5 and ZnT7 expression using considerable siRNA-mediated knockdown of RPMCs was examined and, afterwards, the impact on cell apoptosis was investigated. Increased levels of apoptosis were observed after knockdown of ZnT5 and ZnT7. Furthermore, overexpression of ZnT5 and ZnT7 is accompanied by activation of PI3K/Akt pathway and inhibiting HG-induced apoptosis. This study suggests that the zinc transporting system in RPMCs is influenced by exposure to HG, particularly ZnT5 and ZnT7. This may account for the inhibition of HG-induced RPMC apoptosis and peritoneum injury, likely through targeting PI3K/Akt pathway-mediated cell survival. PMID:23275032

Zhang, Xiuli; Liang, Dan; Guo, Baolei; Deng, Wenyan; Chi, Zhi-Hong; Cai, Yuan; Wang, Lining; Ma, Jianfei

2013-04-01

296

Development of concentrator solar cells  

SciTech Connect

A limited pilot production run on PESC silicon solar cells for use at high concentrations (200 to 400 suns) is summarized. The front contact design of the cells was modified for operation without prismatic covers. The original objective of the contract was to systematically complete a process consolidation phase, in which all the, process improvements developed during the contract would be combined in a pilot production run. This pilot run was going to provide, a basis for estimating cell costs when produced at high throughput. Because of DOE funding limitations, the Photovoltaic Concentrator Initiative is on hold, and Applied Solar`s contract was operated at a low level of effort for most of 1993. The results obtained from the reduced scope pilot run showed the effects of discontinuous process optimization and characterization. However, the run provided valuable insight into the technical areas that can be optimized to achieve the original goals of the contract.

Not Available

1994-08-01

297

High Efficiency InP Solar Cells from Low Toxicity Tertiarybutylphosphine  

NASA Technical Reports Server (NTRS)

Large scale manufacture of phosphide based semiconductor devices by organo-metallic vapor phase epitaxy (OMVPE) typically requires the use of highly toxic phosphine. Advancements in phosphine substitutes have identified tertiarybutylphosphine (TBP) as an excellent precursor for OMVPE of InP. High quality undoped and doped InP films were grown using TBP and trimethylindium. Impurity doped InP films were achieved utilizing diethylzinc and silane for p and n type respectively. 16 percent efficient solar cells under air mass zero, one sun intensity were demonstrated with Voc of 871 mV and fill factor of 82.6 percent. It was shown that TBP could replace phosphine, without adversely affecting device quality, in OMVPE deposition of InP thus significantly reducing toxic gas exposure risk.

Hoffman, Richard W., Jr.; Fatemi, Navid S.; Wilt, David M.; Jenkins, Phillip P.; Brinker, David J.; Scheiman, David A.

1994-01-01

298

High-throughput synthesis and screening of photon absorbers and photocatalysts for solar fuel cells  

NASA Astrophysics Data System (ADS)

Joint Center for Artificial Photosynthesis is a D.O.E. Energy Innovation Hub conceived to develop solar fuel cell technologies by bringing together the critical mass of scientist and engineers nationwide. The High-Throughput Experimentation group at JCAP is developing pipelines for accelerated discovery of new materials - photon absorbers, photoelectrochemical and electrochemical catalysts - using combinatorial approaches (ink-jet, sol-gel, physical vapor deposition). Thin films of semiconducting metal-oxides, sulfides, nitrides and phosphides are synthesized and screened in high-throughput according to their optical and photoelectrochemical properties, as well as structure and phase. Vast libraries of materials and data are generated and made available to inside and outside research groups. Here we present data on binary, ternary and quaternary metal-oxide systems prepared by the ink-jet technology. The systems include tungsten-based photo-absorbers and nickel-iron-based catalysts for water splitting.

Mitrovic, Slobodan; Marcin, Martin; Lin, Sean; Jin, Jian

2012-02-01

299

Highly Mismatched Alloys for Intermediate Band Solar Cells  

E-print Network

comparison to multijunction solar cells. A detailed balanceachieved with multijunction solar cells based on standardmultijunction designs for improving the power conversion efficiency of solar cells [

2005-01-01

300

Solar cell circuit and method for manufacturing solar cells  

NASA Technical Reports Server (NTRS)

The invention is a novel manufacturing method for making multi-junction solar cell circuits that addresses current problems associated with such circuits by allowing the formation of integral diodes in the cells and allows for a large number of circuits to readily be placed on a single silicon wafer substrate. The standard Ge wafer used as the base for multi-junction solar cells is replaced with a thinner layer of Ge or a II-V semiconductor material on a silicon/silicon dioxide substrate. This allows high-voltage cells with multiple multi-junction circuits to be manufactured on a single wafer, resulting in less array assembly mass and simplified power management.

Mardesich, Nick (Inventor)

2010-01-01

301

High-efficiency silicon solar cell research  

NASA Technical Reports Server (NTRS)

High efficiency solar cells were characterized. Silicon solar cell computer modeling was presented. New designs of matter insulator n-p (MINP) were discussed and a new structure called a floating emitter cell was proposed for 20% and higher efficiency. Various techniques for making high efficiency silicon solar cells were described.

Daud, T.

1984-01-01

302

Solar cell spectral response characterization  

NASA Technical Reports Server (NTRS)

The absolute spectral response of solar cells is reported in the 400-1000-nm spectral region. Measurements were performed using two different types of monochromatic sources: amplitude-stabilized CW laser lines and interference filters with an incandescent lamp. Both types of calibration procedures use electrical substitution radiometry as the basis of traceability to absolute SI units. The accuracy of the calibration is shown to be limited by the nonideal characteristics of the solar cells themselves, specifically spatial nonuniformities and nonlinearities induced by high light levels.

Zalewski, E. F.; Geist, J.

1979-01-01

303

New mounting improves solar-cell efficiency  

NASA Technical Reports Server (NTRS)

Method boosts output by about 20 percent by trapping and redirecting solar radiation without increasing module depth. Mounted solar-cell array is covered with internally reflecting plate. Plate is attached to each cell by transparent adhesive, and space between cells is covered with layer of diffusely reflecting material. Solar energy falling on space between cells is diffused and reflected internally by plate until it is reflected onto solar cell.

Shepard, N. F., Jr.

1980-01-01

304

Large area thin film cadmium telluride heterojunction solar cells  

NASA Astrophysics Data System (ADS)

Cadmium telluride films have been deposited by the direct combination of the elements on the surface of heated substrates in hydrogen. The resistivity of p-type films was controlled by (1) using a cadmium-deficient reaction mixture, and (2) adding a dopant to a nearly stoichiometric reaction mixture. Heterojunction solar cells were prepared from p-type cadmium telluride films by using cadmium oxide, cadmium sulfide, tin-doped indium oxide, and zinc oxide, deposited by ion-beam sputtering, spray pyrolysis, or vacuum evaporation, as the window material. Thus far, n-ITO/p-CdTe solar cells have the highest AMl efficiency, 8.1 percent for cells of 1 sq cm area. All heterojunction cells exhibit some degradation under continuous illumination, which may be minimized by passivation.

Chu, T. L.; Chu, S. S.; Firszt, F.; Nassem, H. A.; Stawski, R.

305

Evaluation of solar cell materials for a Solar Power Satellite  

NASA Technical Reports Server (NTRS)

Alternative solar cell materials being considered for the solar power satellite are described and price, production, and availability projections through the year 2000 are presented. The chief materials considered are silicon and gallium arsenide.

Glaser, P. E.; Almgren, D. W.; Csigi, K. I.

1980-01-01

306

Solar Energy Materials & Solar Cells 91 (2007) 15991610 Improving solar cell efficiency using photonic band-gap materials  

E-print Network

) solar energy conversion systems (or solar cells) are the most widely used power systems. HoweverSolar Energy Materials & Solar Cells 91 (2007) 1599­1610 Improving solar cell efficiency using Propulsion Laboratory, California Institute of Technology, Mail Stop T1714 106, 4800 Oak Grove Drive

Dowling, Jonathan P.

307

Asymmetric tandem organic solar cells  

NASA Astrophysics Data System (ADS)

Organic photovoltaics (OPVs) is an area that has attracted much attention recently as a potential low cost, sustainable source of energy with a good potential for full-scale commercialisation. Understanding the factors that determine the efficiency of such cells is therefore a high priority, as well as developing ways to boost efficiency to commercially-useful levels. In addition to an intensive search for new materials, significant effort has been spent on ways to squeeze more performance out of existing materials, such as multijunction cells. This thesis investigates double junction tandem cells in the context of small molecule organic materials. . Two different organic electron donor materials, boron subphthalocyanine chloride (SubPc) and aluminium phthalocyanine chloride (ClAlPc) were used as donors in heterojunctions with C60 to create tandem cells for this thesis. These materials have been previously used for solar cells and the absorption spectra of the donor materials complement each other, making them good candidates for tandem cell architectures. The design of the recombination layer between the cells is considered first, with silver nanoparticles demonstrated to work well as recombination centres for charges from the front and back sub-cells, necessary to avoid a charge build-up at the interface. The growth conditions for the nanoparticles are optimised, with the tandem cells outperforming the single heterojunction architecture. Optical modelling is considered as a method to improve the understanding of thin film solar cells, where interference effects from the reflective aluminium electrode are important in determining the magnitude of absorption a cell can achieve. The use of such modelling is first demonstrated in hybrid solar cells based on a SubPc donor with a titanium oxide (TiOx) acceptor; this system is ideal for observing the effects of interference as only the SubPc layer has significant absorption. The modelling is then applied to tandem cells where it is used to predict the short-circuit current (Jsc) generation of the sub-cells, which is not accessible experimentally. Current-matching is then used to predict the Jsc of the complete tandem device. . As a support to the optical modelling, ellipsometry measurements of thin films of ClAlPc are presented. These films of known thickness are analysed to extract the complex refractive index for use in optical modelling calculations. A dependence of the complex refractive index on film thickness and substrate is also noted. Finally, the external quantum efficiency (EQE) technique is considered as applied to solar cells, and an additional method is proposed to characterise current balancing in asymmetric tandem cells under illumination. This technique is verified experimentally by two separate sets of data..

Howells, Thomas J.

308

The monitoring possibility of some mammalian cells for zinc concentrations on metallic materials.  

PubMed

Zinc plating is widely used to protect steels against corrosion. However, the possibility of a high environmental risk for zinc has been recently discussed among advanced countries and more environmentally-friendly substitutes are required urgently. Therefore, monitoring zinc concentration changes on metallic materials such as steel is very important. We chose to measure zinc concentration changes in some mammalian cells and confirmed that V79 cells were highly sensitive to changes in zinc concentrations. In this study, the following process was applied to the proprietary production for tin-zinc alloy films on steel using V79 cells. Specimens were immersed in PBS to produce extracts. Zinc concentrations in the extracts almost corresponded to zinc concentrations on steel surfaces. When extracts were added to a V79 cell culture, colony formation was inhibited, and inhibition increased with increases in zinc concentrations. Changes in zinc concentrations on steel surfaces with heat treatment could be monitored relatively well by V79 cells, even though the results were still semi-quantitative. PMID:22331507

Ogawa, Akiko; Okuda, Naoaki; Hio, Katsuya; Kanematsu, Hideyuki; Tamauchi, Hidekazu

2012-05-01

309

Solar-Cell Slide Rule  

NASA Technical Reports Server (NTRS)

Slide rule relates efficiency, impurity types, impurity concentrations, and process types. Solar cell slide rule calculations are determination of allowable impurity concentration for nonredistributive process, determination of impurity buildup factor for redistributive process and determination of allowable impurity concentration for redistributive process.

Yamakawa, K. A.

1983-01-01

310

Key Physical Mechanisms in Nanostructured Solar Cells  

SciTech Connect

The objective of the project was to study both theoretically and experimentally the excitation, recombination and transport properties required for nanostructured solar cells to deliver energy conversion efficiencies well in excess of conventional limits. These objectives were met by concentrating on three key areas, namely, investigation of physical mechanisms present in nanostructured solar cells, characterization of loss mechanisms in nanostructured solar cells and determining the properties required of nanostructured solar cells in order to achieve high efficiency and the design implications.

Dr Stephan Bremner

2010-07-21

311

EE580 Solar Cells Todd J. Kaiser  

E-print Network

7/21/2010 1 EE580 ­ Solar Cells Todd J. Kaiser · Lecture 05 · P-N Junction 1Montana State University: Solar Cells Lecture 5: P-N Junction P-N Junction · Solar Cell is a large area P-N junction electron (hole) positive) 2Montana State University: Solar Cells Lecture 5: P-N Junction p-n Junction p n P

Kaiser, Todd J.

312

Process of making solar cell module  

DOEpatents

A process is presented for the manufacture of solar cell modules. A solution comprising a highly plasticized polyvinyl butyral is applied to a solar cell array. The coated array is dried and sandwiched between at last two sheets of polyvinyl butyral and at least two sheets of a rigid transparent member. The sandwich is laminated by the application of heat and pressure to cause fusion and bonding of the solar cell array with the rigid transparent members to produce a solar cell module.

Packer, M.; Coyle, P.J.

1981-03-09

313

The cytotoxic effects of titanium oxide and zinc oxide nanoparticles oh Human Cervical Adenocarcinoma cell membranes  

NASA Astrophysics Data System (ADS)

The importance of titanium dioxide (TiO2) and zinc oxide (ZnO), inorganic metal oxides nanoparticles (NPs) stems from their ubiquitous applications in personal care products, solar cells and food whitening agents. Hence, these NPs come in direct contact with the skin, digestive tracts and are absorbed into human tissues. Currently, TiO2 and ZnO are considered safe commercial ingredients by the material safety data sheets with no reported evidence of carcinogenicity or ecotoxicity, and do not classify either NP as a toxic substance. This study examined the direct effects of TiO2 and ZnO on HeLa cells, a human cervical adenocarcinonma cell line, and their membrane mechanics. The whole cell patch-clamp technique was used in addition to immunohistochemistry staining, TEM and atomic force microscopy (AFM). Additionally, we examined the effects of dexamethasone (DXM), a glucocorticoid steroid known to have an effect on cell membrane mechanics. Overall, TiO2 and ZnO seemed to have an adverse effect on cell membrane mechanics by effecting cell proliferation, altering cellular structure, decreasing cell-cell adhesion, activating existing ion channels, increasing membrane permeability, and possibly disrupting cell signaling.

Mironava, Tatsiana; Applebaum, Ariella; Applebaum, Eliana; Guterman, Shoshana; Applebaum, Kayla; Grossman, Daniel; Gordon, Chris; Brink, Peter; Wang, H. Z.; Rafailovich, Miriam

2013-03-01

314

Hyperforin changes the zinc-storage capacities of brain cells.  

PubMed

In vitro and in vivo experiments were carried out to investigate the consequences on brain cells of a chronic treatment with hyperforin, a plant extract known to dissipate the mitochondrial membrane potential and to release Zn(2+) and Ca(2+) from these organelles. Dissociated cortical neurons were grown in a culture medium supplemented with 1 ?M hyperforin. Live-cell imaging experiments with the fluorescent probes FluoZin-3 and Fluo-4 show that a 3 day-hyperforin treatment diminishes the size of the hyperforin-sensitive pools of Ca(2+) and Zn(2+) whereas it increases the size of the DTDP-sensitive pool of Zn(2+) without affecting the ionomycin-sensitive pool of Ca(2+). When assayed by quantitative PCR the levels of mRNA coding for metallothioneins (MTs) I, II and III were increased in cortical neurons after a 3 day-hyperforin treatment. This was prevented by the zinc chelator TPEN, indicating that the plant extract controls the expression of MTs in a zinc-dependent manner. Brains of adult mice who received a daily injection (i.p.) of hyperforin (4 mg/kg/day) for 4 weeks had a higher sulphur content than control animals. They also exhibited an enhanced expression of the genes coding for MTs. However, the long-term treatment did not affect the brain levels of calcium and zinc. Based on these results showing that hyperforin influences the size of the internal pools of Zn(2+), the expression of MTs and the brain cellular sulphur content, it is proposed that hyperforin changes the Zn-storage capacity of brain cells and interferes with their thiol status. PMID:21854792

Gibon, Julien; Richaud, Pierre; Bouron, Alexandre

2011-12-01

315

Titania solar cells: new photovoltaic technology  

Microsoft Academic Search

Titania solar cells are a new type of photovoltaic device invented by Professor Michael Grtzel at Ecole Polytechnique Federale de Lausanne (Switzerland). Titania solar cells convert sunlight directly into electricity through a process similar to photosynthesis. It has performance advantages over other solar cells, which include the ability to perform well in low light and shade, and to perform consistently

George Phani; Gavin Tulloch; David Vittorio; Igor Skryabin

2001-01-01

316

Light trapping in amorphous silicon solar cells  

Microsoft Academic Search

In order to simultaneously decrease the production costs of thin film silicon solar cells and obtain higher performances, the authors have studied the possibility to increase the light trapping effect within thin film silicon solar cells deposited on flexible plastic substrates. In this context, different nano-structure shapes useable for the back contacts of amorphous silicon solar cells on plastic substrates

Vanessa Terrazzoni-Daudrix; Joelle Guillet; Xavier Niquille; Arvind Shah; R. Morf; A. Tishchenko; V. Brioude; O. Parriaux; D. Fischer

317

Quantum Junction Solar Cells Jiang Tang,,  

E-print Network

To date, the bandgaps of light-absorbing semiconductors making up multijunction solar cells have been quantum dots offer avenues to inexpensive and robust multijunction solar cell architectures. RecentlyQuantum Junction Solar Cells Jiang Tang,, Huan Liu,, David Zhitomirsky, Sjoerd Hoogland, Xihua

318

EE580 Solar Cells Todd J. Kaiser  

E-print Network

7/21/2010 1 EE580 ­ Solar Cells Todd J. Kaiser · Lecture 02 Microfabrication ­ A combination · Photolithograpy · Depostion · Etching 1 Montana State University: Solar Cells Lecture 2: Microfabrication Flow Montana State University: Solar Cells Lecture 2: Microfabrication Questions · What is heat? · Heat

Kaiser, Todd J.

319

EE580 Solar Cells Todd J. Kaiser  

E-print Network

to the load 3Montana State University: Solar Cells Lecture 10: Summary Photovoltaic Effect Creation of Voltage Montana State University: Solar Cells Lecture 10: Summary 7 Photovoltaic Myth #3 · Grid-connected PV Photovoltaic Myth #7 · PV involves toxic materials ­ Minimal toxic materials in silicon solar cells, but used

Kaiser, Todd J.

320

Development of high band gap materials for tandem solar cells and simulation studies on mechanical tandem solar cells  

NASA Astrophysics Data System (ADS)

Development of low cost, high efficiency tandem solar cells is essential for large scale adoption of solar energy especially in densely populated regions of the world. In this thesis four-terminal mechanical (stack like) tandem solar cells were evaluated using detailed simulation models and design criteria for selecting candidate materials were established. Since silicon solar cells are low cost and have a multi-giga watt global manufacturing and supply chain capacity already in place then only tandem stacks incorporating silicon as one of the layers in the device was investigated. Two candidate materials which have high band gaps that could be used as top cells in the mechanical tandem device were explored as part of the thesis. Dye-sensitized solar cells (DSSC) sensitized with N719 dye (one of the candidates for the top cell) were fabricated with the goal of enabling a flexible processing path to lower cost. Stainless steel (SS) mesh substrates were used to fabricate anodes for flexible DSSC in order to evaluate them as replacements for more expensive Transparent Conducting Oxides (TCO's). Loss mechanisms in DSSC's due to SS mesh oxidation were quantified and protective coatings to prevent oxidation of SS mesh were developed. The second material which was evaluated for use as the top cell was copper zinc tin sulfide (CZTS). CZTS was deposited through a solution deposition route. Detailed investigations were done on the deposited films to understand the chemistry, crystal structure and its opto-electronic properties. Deposited CZTS films were found to be highly crystalline in <112> direction. The films had a direct band gap of 1.5 eV with absorption coefficient greater than 104 cm -1 in agreement with published values. In the second part of the thesis detailed electrical and optical simulation models of the mechanical tandem solar cells were developed based on the most up-to-date materials physical constants available for each layer. The modeling was used to quantify the various theoretical and practical loss mechanisms in tandem devices. Two configurations were evaluated, first was silicon / germanium tandem cell and the second was gallium arsenide / silicon tandem cell. The simulation models were validated by their close match to the performance of experimental standalone solar cells devices reported in the literature. Finally the efficiency limits of the present generation of high band gap solar cells were discussed. Voltage and current loss of the high band gap solar cells were compared with present generation silicon solar cells and challenges in improving their efficiencies were described.

Vijayakumar, Vishnuvardhanan

321

Nanostructured Materials for Solar Cells  

NASA Technical Reports Server (NTRS)

The use of both inorganic and organic nanostructured materials in producing high efficiency photovoltaics is discussed in this paper. Recent theoretical results indicate that dramatic improvements in device efficiency may be attainable through the use of semiconductor quantum dots in an ordinary p-i-n solar cell. In addition, it has also recently been demonstrated that quantum dots can also be used to improve conversion efficiencies in polymeric thin film solar cells. A similar improvement in these types of cells has also been observed by employing single wall carbon nanotubes. This relatively new carbon allotrope may assist both in the disassociation of excitons as well as carrier transport through the composite material. This paper reviews the efforts that are currently underway to produce and characterize these nanoscale materials and to exploit their unique properties.

Bailey, Sheila; Raffaelle, Ryne; Castro, Stephanie; Fahey, S.; Gennett, T.; Tin, P.

2003-01-01

322

A novel chlorophyll solar cell  

NASA Astrophysics Data System (ADS)

The photosynthetic process is reviewed in order to produce a design for a chlorophyll solar cell. In a leaf, antenna chlorophyll absorbs light energy and conducts it to an energy trap composed of a protein and two chlorophyll molecules, which perform the oxidation-reduction chemistry. The redox potential of the trap changes from 0.4 to -0.6 V, which is sufficient to reduce nearby molecules with redox potentials in that range. The reduction occurs by transfer of an electron, and a chlorophyll solar cell would direct the transferred electron to a current carrier. Chlorophyll antenna and traps are placed on a metallic support immersed in an electron acceptor solution, and resulting electrons from exposure to light are gathered by a metallic current collector. Spinach chlorophyll extracted, purified, and applied in a cell featuring a Pt collector and an octane water emulsion resulted in intensity independent voltages.

Ludlow, J. C.

323

Bioactive Dietary Polyphenols on Zinc Transport across the Intestinal Caco-2 Cell Monolayers  

PubMed Central

Polyphenolic compounds are known to possess many beneficial health effects, including the antioxidative activities of scavenging reactive oxygen species and chelating metals, such as iron and zinc. Tea and red wine are thought to be important sources of these compounds. However, some polyphenolic compounds can also reduce the absorption of iron, and possibly other trace metals, when included in a diet. There is very little information on the effect of dietary polyphenolic compounds on the status of trace elements other than iron. We examined the effects of epigallocatechin-3-gallate (EGCG), green tea extract (GT) and grape seed extract (GSE) on the absorption of 65Zn and compared them with their effects on 55Fe absorption in human intestinal Caco-2 cells grown on microporous membrane inserts. The levels of EGCG, GT and GSE used in this study were within the physiological ranges and did not affect the integrity of the Caco-2 cell monolayers. GSE significantly (P < 0.05) reduced zinc transport across the cell monolayer, and the decreased zinc transport was associated with a reduction in apical zinc uptake. However, EGCG and GT did not alter zinc absorption. In contrast, the polyphenolic compounds in EGCG, GT and GSE almost completely blocked transepithelial iron transport across the cell monolayer. The effect of GSE on zinc absorption was very different from that on iron absorption. While GSE decreased zinc absorption by reducing apical zinc uptake, the polyphenolic compounds inhibited iron absorption by enhancing apical iron uptake. GSE inhibited zinc absorption similarly to that observed for phytate. Phytate significantly (P < 0.05) decreased transepithelial zinc transport by reducing apical zinc uptake. The inhibition of zinc absorption may be due to the presence of procyanidins in GSE, which bind zinc with high affinity and block the transport of zinc across the apical membrane of enterocytes. Further research on the absorption of zinc as zinc-polyphenol complexes and free zinc should provide further insight into the process of dietary zinc absorption in the presence of GSE and other bioactive dietary polyphenols. The present study suggests that some individuals should consider their zinc status if they regularly consume procyanidin-containing foods in their diet. However, further studies, especially in vivo studies, are needed to confirm these results. PMID:21410257

KIM, EUN-YOUNG; PAI, TONG-KUN; HAN, OKHEE

2011-01-01

324

Nanowire perovskite solar cell.  

PubMed

Organolead iodide perovskite, CH3NH3PbI3, was prepared in the form of nanowire by means of a small quantity of aprotic solvent in two-step spin-coating procedure. One-dimensional nanowire perovskite with the mean diameter of 100 nm showed faster carrier separation in the presence of hole transporting layer and higher lateral conductivity than the three-dimensional nanocuboid crystal. Reduction in dimensionality resulted in the hypsochromic shift of both absorption and fluorescence spectra, indicative of more localized exciton states in nanowires. The best performing device employing nanowire CH3NH3PbI3 delivered photocurrent density of 19.12 mA/cm(2), voltage of 1.052 V, and fill factor of 0.721, leading to a power conversion efficiency (PCE) of 14.71% at standard AM 1.5G solar illumination. A small I-V hysteresis was observed, where a PCE at forward scan was measured to be 85% of the PCE at reverse scan. PMID:25710268

Im, Jeong-Hyeok; Luo, Jingshan; Franckevi?ius, Marius; Pellet, Norman; Gao, Peng; Moehl, Thomas; Zakeeruddin, Shaik Mohammed; Nazeeruddin, Mohammad Khaja; Grtzel, Michael; Park, Nam-Gyu

2015-03-11

325

Fabrication of boron-phosphide neutron detectors  

Microsoft Academic Search

Boron phosphide is a potentially viable candidate for high neutron flux neutron detectors. The authors have explored chemical vapor deposition methods to produce such detectors and have not been able to produce good boron phosphide coatings on silicon carbide substrates. However, semi-conducting quality films have been produced. Further testing is required.

M. Fitzsimmons; R. Pynn

1997-01-01

326

Towards stable silicon nanoarray hybrid solar cells  

PubMed Central

Silicon nanoarray hybrid solar cells benefit from the ease of fabrication and the cost-effectiveness of the hybrid structure, and represent a new research focus towards the utilization of solar energy. However, hybrid solar cells composed of both inorganic and organic components suffer from the notorious stability issue, which has to be tackled before the hybrid solar cells could become a viable alternative for harvesting solar energy. Here we show that Si nanoarray/PEDOT:PSS hybrid solar cells with improved stability can be fabricated via eliminating the water inclusion in the initial formation of the heterojunction between Si nanoarray and PEDOT:PSS. The Si nanoarray hybrid solar cells are stable against rapid degradation in the atmosphere environment for several months without encapsulation. This finding paves the way towards the real-world applications of Si nanoarray hybrid solar cells. PMID:24430057

He, W. W.; Wu, K. J.; Wang, K.; Shi, T. F.; Wu, L.; Li, S. X.; Teng, D. Y.; Ye, C. H.

2014-01-01

327

22. 8% efficient silicon solar cell  

SciTech Connect

A new silicon solar cell structure, the passivated emitter and rear cell, is described. The cell structure has yielded independently confirmed efficiencies of up to 22.8%, the highest ever reported for a silicon cell.

Blakers, A.W.; Wang, A.; Milne, A.M.; Zhao, J.; Green, M.A. (Solar Photovoltaic Laboratory, Joint Microelectronics Research Centre, University of New South Wales, Kensington 2033, Australia (AU))

1989-09-25

328

DETAIL OF ZINC CLEANER CELL INTERIOR (EXPOSED AT F/45 FOR ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL OF ZINC CLEANER CELL INTERIOR (EXPOSED AT F/45 FOR DEPTH OF FIELD PURPOSES). NOTE GALIGHER STYLE BAFFLES AND TENDENCY OF ZINC TO BUILD UP ON CELL COMPONENTS. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

329

Solar Cell Simulation  

NSDL National Science Digital Library

In this activity, learners model the flow of energy from the sun as it enters a photovoltaic cell, moves along a wire and powers a load. The game-like atmosphere engages younger learners and helps them understand the continuous nature of the flow of energy. Note: to do this activity you need access to a large open area outside (e.g., a field or playground).

Susan Schleith

2007-01-01

330

Advanced solar cell  

SciTech Connect

A photovoltaic cell is described comprising: a layered extrinsic semiconductor having a substantially neutral base layer sandwiched between two heavily doped layers having opposite conductivity types to form a P-N junction within the semiconductor; and means for applying an externally generated electric field to the semiconductor to enhance a depletion region formed around the P-N junction to extend into the base layer when photo radiation impinges on the semiconductor.

Hingorani, N.G.; Mehta, H.

1993-06-01

331

Crystal and electronic structures of CaAl{sub 2}Si{sub 2}-type rare-earth copper zinc phosphides RECuZnP{sub 2} (RE=Pr, Nd, Gd-Tm, Lu)  

SciTech Connect

The quaternary rare-earth phosphides RECuZnP{sub 2} (RE=Pr, Nd, Gd-Tm, Lu) have been prepared by reaction of the elements at 900 {sup o}C, completing this versatile series which forms for nearly all RE metals. They adopt the trigonal CaAl{sub 2}Si{sub 2}-type structure (Pearson symbol hP5, space group P3-bar m1, Z=1), as confirmed by single-crystal X-ray diffraction analysis on ErCuZnP{sub 2} and powder X-ray diffraction analysis on the remaining members. The Cu and Zn atoms are assumed to be disordered over the single transition-metal site. Band structure calculations on a hypothetically ordered YCuZnP{sub 2} model suggest a semimetal, with a zero band gap between the valence and conduction bands. This electronic structure is supported by XPS valence band spectra for RECuZnP{sub 2} (RE=Gd-Er), in which the intensity drops off smoothly at the Fermi edge. The absence of a band gap permits the electron count to deviate from the precise value of 16 e{sup -} per formula unit, as demonstrated by the formation of a solid solution in GdCu{sub x}Zn{sub 2-x}P{sub 2} (1.0{<=}x{<=}1.3), while still retaining the CaAl{sub 2}Si{sub 2}-type structure. Because the Cu 2p XPS spectra indicate that the Cu atoms are always monovalent, the substitution of Cu for Zn leads to a decrease in electron count and a lowering of the Fermi level in the valence band. The magnetic susceptibility of RECuZnP{sub 2} (RE=Gd-Er), which obeys the Curie-Weiss law, confirms the presence of trivalent RE atoms. -- Graphical abstract: The absence of a band gap in the semimetallic quaternary rare-earth phosphides RECuZnP{sub 2} permits the formation of a solid solution such as GdCu{sub x}Zn{sub 2-x}P{sub 2} through hole-doping of the valence band. Display Omitted

Blanchard, Peter E.R.; Stoyko, Stanislav S.; Cavell, Ronald G. [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2 (Canada); Mar, Arthur, E-mail: arthur.mar@ualberta.c [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2 (Canada)

2011-01-15

332

Hybrid robotic wheelchair with photovoltanic solar cell and fuel cell  

Microsoft Academic Search

A hybrid robotic wheelchair powered by three energy sources, a battery, a photovoltanic solar cell, and a hydrogen fuel cell is proposed in this paper. The advantage of using a photovoltanic solar cell (a solar panel) is that it produces power without requiring use of fossil fuels. The advantage of using a fuel cell is that a hydrogen tank may

Y. Takahashi; S. Matsuo; K. Kawakami

2008-01-01

333

Solar cells Improved Hybrid Solar Cells via in situ UV Polymerization  

E-print Network

Solar cells Improved Hybrid Solar Cells via in situ UV Polymerization Sanja Tepavcevic, Seth B-enhanced solar energy conversion. By using this simple in situ UV polymerization method that couples mobility of the photoactive layer can be enhanced. 1. Introduction Hybrid solar cells have been developed

Sibener, Steven

334

High Temperature Solar Cell Development  

NASA Technical Reports Server (NTRS)

The majority of satellites and near-earth probes developed to date have used photovoltaic arrays for power generation. If future mission to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. In this paper, we derive the optimum bandgap as a function of the operating temperature.

Landis, Geoffrey A.; Raffaelle, Ryne P.; Merritt, Danielle

2004-01-01

335

Dye-Sensitized Solar Cells  

NSDL National Science Digital Library

This lesson from The Lawrence Hall of Science was taught in spring 2012 and teaches students about nano and environmental technologies. Students will create "dye-sensitized solar cells (DSSC) using nano-crystalline titanium dioxide." This page includes links to the Source Articles for the Hands-on Module and Project Staff Write-ups of the Hands-on Module. Additionally, five documents provide lecture and lab materials for instructor use.

336

The effect of process conditions on the performance of epitaxial InP solar cells  

NASA Technical Reports Server (NTRS)

Indium phosphide solar cells have a higher resistance to electron irradiation than Si or GaAs cells of comparable junction depth. As a result, there is much interest in the use of this material for space applications. Cells of this material were made in bulk InP by a number of techniques, including ion implantation, direct diffusion in sealed ampoules, and by open tube diffusion. However, it is generally considered that the epitaxial approach will be superior to all of these techniques. The epitaxy of InP is considerably more difficult than that of gallium arsenide, for a number of reasons. Perhaps the most important is the fact that the native oxides of Indium are extremely difficult to remove, as compared to that of Gallium. In addition, thermal treatments for the desorption of these oxides often result in the formation of phosphorus vacancies and free indium on the surface. Thus, inadequate sample preparation before epitaxy, poor reactor cleaning procedures, or poor transition procedures between the growth of successive layers, all give rise to trap phenomena and to high interface recombination velocities. Moreover, the lifetime of the grown material is dominated by the occurrence of native defects, so that it is a strong function of growth parameters. These problems are of special interest to the fabrication of solar cells, where long life-time, combined with the absence of traps, is highly desirable. A study of this problem is described using a non-invasive diagnostic technique which was developed.

Borrego, J. M.; Ghandi, S. K.

1991-01-01

337

Zinc Induced G2/M Blockage is p53 and p21 Dependent in Normal Human Bronchial Epithelial Cells  

Technology Transfer Automated Retrieval System (TEKTRAN)

The involvement of the p53 and p21 signal pathway in the G2/M cell cycle progression of zinc supplemented normal human bronchial epithelial (NHBE) cells was examined using the siRNA approach. Cells were cultured for one passage in different concentrations of zinc: <0.4 microM (ZD) as zinc-deficient;...

338

Interface engineering for efficient fullerene-free organic solar cells  

NASA Astrophysics Data System (ADS)

We demonstrate the role of zinc oxide (ZnO) morphology and addition of an acceptor interlayer to achieve high efficiency fullerene-free bulk heterojunction inverted organic solar cells. Nanopatterning of the ZnO buffer layer enhances the effective light absorption in the active layer, and the insertion of a twisted perylene acceptor layer planarizes and decreases the electron extraction barrier. Along with an increase in current homogeneity, the reduced work function difference and selective transport of electrons prevent the accumulation of charges and decrease the electron-hole recombination at the interface. These factors enable an overall increase of efficiency to 4.6%, which is significant for a fullerene-free solution-processed organic solar cell.

Shivanna, Ravichandran; Rajaram, Sridhar; Narayan, K. S.

2015-03-01

339

Three-junction solar cell  

DOEpatents

A photovoltaic solar cell is formed in a monolithic semiconductor. The cell contains three junctions. In sequence from the light-entering face, the junctions have a high, a medium, and a low energy gap. The lower junctions are connected in series by one or more metallic members connecting the top of the lower junction through apertures to the bottom of the middle junction. The upper junction is connected in voltage opposition to the lower and middle junctions by second metallic electrodes deposited in holes 60 through the upper junction. The second electrodes are connected to an external terminal.

Ludowise, Michael J. (Cupertino, CA)

1986-01-01

340

Silicon solar cell fabrication technology  

NASA Technical Reports Server (NTRS)

The laser cell scanner was used to characterize a number of solar cells made in various materials. An electron beam-induced current (EBIC) study was performed using a stereoscan scanning electron microscope. Planar p-n junctions were analyzed. A theory for the EBIC based on the analytical solution of the ambipolar diffusion equation under the influence of electron beam excitation parameter z (which is related to beam penetration), the junction depth Z sub j, the beam current and the surface recombination, was formulated and tested. The effect of a grain boundary was studied.

Stafsudd, O. M.

1979-01-01

341

Spectral sensitization of nanocrystalline solar cells  

DOEpatents

This invention relates to dye sensitized polycrystalline photoelectrochemical solar cells for use in energy transduction from light to electricity. It concerns the utility of highly absorbing organic chromophores as sensitizers in such cells and the degree to which they may be utilized alone and in combination to produce an efficient photoelectrochemical cell, e.g., a regenerative solar cell.

Spitler, Mark T. (Concord, MA); Ehret, Anne (Malden, MA); Stuhl, Louis S. (Bedford, MA)

2002-01-01

342

Recent Advances in Solar Cell Technology  

NASA Technical Reports Server (NTRS)

The advances in solar cell efficiency, radiation tolerance, and cost over the last decade are reviewed. Potential performance of thin-film solar cells in space are discussed, and the cost and the historical trends in production capability of the photovoltaics industry are considered with respect to the requirements of space power systems. Concentrator cells with conversion efficiency over 30%, and nonconcentrating solar cells with efficiency over 25% are now available, and advanced radiation-tolerant cells and lightweight, thin-film arrays are both being developed. Nonsolar applications of solar cells, including thermophotovoltaics, alpha- and betavoltaics, and laser power receivers, are also discussed.

Landis, Geoffrey A.; Bailey, Sheila G.; Piszczor, Michael F., Jr.

1996-01-01

343

Solar cell contacts  

NASA Technical Reports Server (NTRS)

Two experimental contact systems were examined and compared to a baseline contact system consisting of evaporated layers of titanium, palladium, and silver and an electroplated layer of copper. The first experimental contact system consisted of evaporated layers of titanium, nickel, and copper and an electroplated layer of copper. This system performed as well as the baseline system in all respects, including its response to temperature stress tests, to a humidity test, and to an accelerated aging test. In addition, the cost of this system is estimated to be only 43 percent of the cost of the baseline system at a production level of 25 MW/year. The second experimental contact system consisted of evaporated layers of nickel and copper and an electroplated layer of copper. Cells with this system show serious degradation in a temperature stress test at 350 C for 30 minutes. Auger electron spectroscopy was used to show that the evaporated nickel layer is not an adequate barrier to copper diffusion even at temperatures as low as 250 C. This fact brings into question the long-term reliability of this contact system.

Meier, D. L.; Campbell, R. B.; Davis, J. R., Jr.; Rai-Choudhury, P.; Sienkiewicz, L. J.

1982-01-01

344

Status of multijunction solar cells  

NASA Technical Reports Server (NTRS)

This paper describes Applied Solar's present activity on Multijunction (MJ) space cells. We have worked on a variety of MJ cells, both monolithic and mechanically stacked. In recent years, most effort has been directed to GaInP2/GaAs monolithic cells, grown on Ge substrates, and the status of this cell design will be reviewed here. MJ cells are in demand to provide satellite power because of the acceptance of the overwhelming importance of high efficiency to reduce the area, weight and cost of space PV power systems. The need for high efficiencies has already accelerated the production of GaAs/Ge cells, with efficiencies 18.5-19%. When users realized that MJ cells could provide higher efficiencies (from 22% to 26%) with only fractional increase in costs, the demand for production MJ cells increased rapidly. The main purpose of the work described is to transfer the MOCVD growth technology of MJ high efficiency cells to a production environment, providing all the space requirements of users.

Yeh, Y. C. M.; Chu, C. L.

1996-01-01

345

Extended Temperature Solar Cell Technology Development  

NASA Technical Reports Server (NTRS)

Future NASA missions will require solar cells to operate both in regimes closer to the sun, and farther from the sun, where the operating temperatures will be higher and lower than standard operational conditions. NASA Glenn is engaged in testing solar cells under extended temperature ranges, developing theoretical models of cell operation as a function of temperature, and in developing technology for improving the performance of solar cells for both high and low temperature operation.

Landis, Geoffrey A.; Jenkins, Phillip; Scheiman, David; Rafaelle, Ryne

2004-01-01

346

The advanced solar cell orbital test  

NASA Technical Reports Server (NTRS)

The motivation for advanced solar cell flight experiments is discussed and the Advanced Solar Cell Orbital Test (ASCOT) flight experiment is described. Details of the types of solar cells included in the test and the kinds of data to be collected are given. The orbit will expose the cells to a sufficiently high radiation dose that useful degradation data will be obtained in the first year.

Marvin, D. C.; Gates, M.

1991-01-01

347

heat treatment for solar cells  

NASA Astrophysics Data System (ADS)

CdTe is an important compound semiconductor for solar cells, and its use in nanowire-based heterostructures may become a critical requirement, owing to the potential scarcity of tellurium. The effects of the CdCl2 heat treatment are investigated on the physical properties of vertically aligned ZnO/CdTe core-shell nanowire arrays grown by combining chemical bath deposition with close space sublimation. It is found that recrystallization phenomena are induced by the CdCl2 heat treatment in the CdTe shell composed of nanograins: its crystallinity is improved while grain growth and texture randomization occur. The presence of a tellurium crystalline phase that may decorate grain boundaries is also revealed. The CdCl2 heat treatment further favors the chlorine doping of the CdTe shell with the formation of chlorine A-centers and can result in the passivation of grain boundaries. The absorption properties of ZnO/CdTe core-shell nanowire arrays are highly efficient, and more than 80% of the incident light can be absorbed in the spectral range of the solar irradiance. The resulting photovoltaic properties of solar cells made from ZnO/CdTe core-shell nanowire arrays covered with CuSCN/Au back-side contact are also improved after the CdCl2 heat treatment. However, recombination and trap phenomena are expected to operate, and the collection of the holes that are mainly photo-generated in the CdTe shell from the CuSCN/Au back-side contact is presumably identified as the main critical point in these solar cells.

Consonni, Vincent; Renet, Sbastien; Garnier, Jrme; Gergaud, Patrice; Arts, Lluis; Michallon, Jrme; Rapenne, Laetitia; Appert, Estelle; Kaminski-Cachopo, Anne

2014-05-01

348

Degradation characteristics of air cathode in zinc air fuel cells  

NASA Astrophysics Data System (ADS)

The zinc air fuel cell (ZAFC) is a promising candidate for electrical energy storage and electric vehicle propulsion. However, its limited durability has become a major obstacle for its successful commercialization. In this study, 2-cell stacks, 25cm cells and three-electrode half-cells are constructed to experimentally investigate the degradation characteristics of the air cathode. The results of electrochemical tests reveal that the peak power density for the 25cm2 cell with a new air cathode is 454mWcm-2, which is twice as the value of the used air cathode. The electrochemical impedance analysis shows that both the charge transfer resistance and the mass transfer resistance of the used air cathodes have increased, suggesting that the catalyst surface area and gas diffusion coefficient have decreased significantly. Additionally, the microstructure and morphology of the catalytic layer (CL) and gas diffusion layer (GDL) are characterized by scanning electron microscopes (SEM). SEM results confirm that the micropores in CL and GDL of the used air cathode are seriously clogged, and many catalyst particles are lost. Therefore, the performance degradation is mainly due to the clogging of micropores and loss of catalyst particles. Furthermore, hypotheses of degradation mechanism and mitigation strategies for GDL and CL are discussed briefly.

Ma, Ze; Pei, Pucheng; Wang, Keliang; Wang, Xizhong; Xu, Huachi; Liu, Yongfeng; peng, Guanlin

2015-01-01

349

Energy Conversion: Nano Solar Cell  

NASA Astrophysics Data System (ADS)

Problems of fossil-fuel-induced climate change have sparked a demand for sustainable energy supply for all sectors of economy. Most laboratories continue to search for new materials and new technique to generate clean energy at affordable cost. Nanotechnology can play a major role in solving the energy problem. The prospect for solar energy using Si-based technology is not encouraging. Si photovoltaics can produce electricity at 20-30 c//kWhr with about 25% efficiency. Nanoparticles have a strong capacity to absorb light and generate more electrons for current as discovered in the recent work of organic and dye-sensitized cell. Using cheap preparation technique such as screen-printing and self-assembly growth, organic cells shows a strong potential for commercialization. Thin Films research group at National University Malaysia has been actively involved in these areas, and in this seminar, we will present a review works on nanomaterials for solar cells and particularly on hybrid organic solar cell based on ZnO nanorod arrays. The organic layer consisting of poly[2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEHPPV) and [6, 6]-phenyl C61-butyric acid 3-ethylthiophene ester (PCBE) was spin-coated on ZnO nanorod arrays. ZnO nanorod arrays were grown on FTO glass substrates which were pre-coated with ZnO nanoparticles using a low temperature chemical solution method. A gold electrode was used as the top contact. The device gave a short circuit current density of 2.4910-4 mA/cm2 and an open circuit voltage of 0.45 V under illumination of a projector halogen light at 100 mW/cm2.

Yahaya, Muhammad; Yap, Chi Chin; Mat Salleh, Muhamad

2009-09-01

350

Optimization of transparent and reflecting electrodes for amorphous silicon solar cells. Annual subcontract report, April 1, 1994--March 31, 1995  

SciTech Connect

Transparent and reflecting electrodes are important parts of the structure of amorphous silicon solar cells. We report improved methods for depositing zinc oxide, deposition of tin nitride as a potential reflection-enhancing diffusion barrier between the a-Si and back metal electrodes. Highly conductive and transparent fluorine-doped zinc oxide was successfully produced on small areas by atmospheric pressure CVD from a less hazardous zinc precursor, zinc acetylacetonate. The optical properties measured for tin nitride showed that the back-reflection would be decreased if tin nitride were used instead of zinc oxide as a barrier layer over silver on aluminum. Niobium-doped titanium dioxide was produced with high enough electrical conductivity so that normal voltages and fill factors were obtained for a-Si cells made on it.

Gordon, R.G. [Harvard Univ., Cambridge, MA (United States)

1995-10-01

351

Determining adaptive and adverse oxidative stress responses in human bronical epithelial cells exposed to zinc  

EPA Science Inventory

Determining adaptive and adverse oxidative stress responses in human bronchial epithelial cells exposed to zincJenna M. Currier1,2, Wan-Yun Cheng1, Rory Conolly1, Brian N. Chorley1Zinc is a ubiquitous contaminant of ambient air that presents an oxidant challenge to the human lung...

352

The effects of zinc status on early growth in infants with sickle cell disease  

Technology Transfer Automated Retrieval System (TEKTRAN)

Growth failure, maturational delay, and alterations in body composition occur in older children and adults with Sickle Cell Disease (SCD). Poor nutritional status, specifically zinc deficiency, has been widely implicated, although infants with SCD have not been studied. We determined zinc status in ...

353

Solar cell system having alternating current output  

NASA Technical Reports Server (NTRS)

A monolithic multijunction solar cell was modified by fabricating an integrated circuit inverter on the back of the cell to produce a device capable of generating an alternating current output. In another embodiment, integrated curcuit power conditioning electronics was incorporated in a module containing a solar cell power supply.

Evans, J. C., Jr. (inventor)

1980-01-01

354

Development of stacked multiple bandgap solar cells  

Microsoft Academic Search

Stacked multiple bandgap solar cells utilize separate junctions or solar cells or selected properties which are combined in series both optically and electrically to obtain higher conversion efficiencies than can be achieved by any of the cells individually. Basic requirements for the successful fabrication of high efficiency tandem structures will be defined, and the apparent practical limitations on the formation

R. P. Ruth; J. J. Coleman; S. W. Zehr; R. D. Dupuis; H. T. Yang; D. L. Miller; P. D. Dapkus

1979-01-01

355

Amorphous Silicon-Carbon Nanostructure Solar Cells  

Microsoft Academic Search

Taking advantage of the ability to fabricate large area graphene and carbon nanotube networks (buckypaper), we produce Schottky junction solar cells using undoped hydrogenated amorphous silicon thin films and nanostructured carbon films. These films are useful as solar cell materials due their combination of optical transparency and conductance. In our cells, they behave both as a transparent conductor and as

Maria Schriver; Will Regan; Matthias Loster; Alex Zettl

2011-01-01

356

Search for new solar cell heats up  

SciTech Connect

Researchers are in the process of developing an organic solar energy cell with a plasticlike material that simplifies the complicated process of creating a working cell - one that is cheap, easy to produce and has a variety of potential applications. The chemical is polyacetylene and can be painted on anything to become a solar cell.

Lipkin, R.

1990-11-05

357

Ultrasonic Bonding of Solar-Cell Leads  

NASA Technical Reports Server (NTRS)

Rolling ultrasonic spot-bonding method successfully joins aluminum interconnect fingers to silicon solar cells with copper metalization. Technique combines best features of ultrasonic rotary seam welding and ultrasonic spot bonding: allows fast bond cycles and high indexing speeds without use of solder or flux. Achieves reliable bonds at production rates without damage to solar cells. Bonding system of interest for all solar-cell assemblies and other assemblies using flat leads (rather than round wires).

Frasch, W.

1984-01-01

358

Bypass diode for a solar cell  

DOEpatents

Bypass diodes for solar cells are described. In one embodiment, a bypass diode for a solar cell includes a substrate of the solar cell. A first conductive region is disposed above the substrate, the first conductive region of a first conductivity type. A second conductive region is disposed on the first conductive region, the second conductive region of a second conductivity type opposite the first conductivity type.

Rim, Seung Bum (Palo Alto, CA); Kim, Taeseok (San Jose, CA); Smith, David D. (Campbell, CA); Cousins, Peter J. (Menlo Park, CA)

2012-03-13

359

Solar Cell Modules With Improved Backskin  

DOEpatents

A laminated solar cell module comprises a front light transmitting support, a plurality of interconnected solar cells encapsulated by a light-transmitting encapsulant material, and an improved backskin formed of an ionomer/nylon alloy. The improved backskin has a toughness and melting point temperature sufficiently great to avoid any likelihood of it being pierced by any of the components that interconnect the solar cells.

Gonsiorawski, Ronald C. (Danvers, MA)

2003-12-09

360

Improved monolithic tandem solar cell  

SciTech Connect

A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surf ace of the InP substrate, (c) a second photoactive subcell on the first subcell; and (d) an optically transparent prismatic cover layer over the second subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched.

Wanlass, M.W.

1991-04-23

361

A Surface-Controlled Solar Cell  

NASA Technical Reports Server (NTRS)

Open-circuit voltage and cell efficiency increased. Proposed technique for controlling recombination velocity on solar-cell surfaces provides cells of increased efficiency and open-circuit voltage. In present cells, uncontrolled surface recombination velocity degrades opencircuit voltage and efficiency. In cell using proposed technique, transparent conducting layer, insulated from cell contacts, biased to enable variable control of surface recombination velocity.

Daud, T.; Crotty, G. T.

1987-01-01

362

Monolithic and mechanical multijunction space solar cells  

SciTech Connect

High-efficiency, lightweight, radiation-resistant solar cells are essential to meet the large power requirements of future space missions. Single-junction cells are limited in efficiency. Higher cell efficiencies could be realized by developing multijunction, multibandgap solar cells. Monolithic and mechanically stacked tandem solar cells surpassing single-junction cell efficiencies have been fabricated. This article surveys the current status of monolithic and mechanically stacked multibandgap space solar cells, and outlines problems yet to be resolved. The monolithic and mechanically stacked cells each have their own problems related to size, processing, current and voltage matching, weight, and other factors. More information is needed on the effect of temperature and radiation on the cell performance. Proper reference cells and full-spectrum range simulators are also needed to measure efficiencies correctly. Cost issues are not addressed, since the two approaches are still in the developmental stage.

Jain, R.K.; Flood, D.J. (NASA Lewis Research Center, Cleveland, OH (United States))

1993-05-01

363

Monolithic and mechanical multijunction space solar cells  

NASA Technical Reports Server (NTRS)

High-efficiency, lightweight, radiation-resistant solar cells are essential to meet the large power requirements of future space missions. Single-junction cells are limited in efficiency. Higher cell efficiencies could be realized by developing multijunction, multibandgap solar cells. Monolithic and mechanically stacked tandem solar cells surpassing single-junction cell efficiencies have been fabricated. This article surveys the current status of monolithic and mechanically stacked multibandgap space solar cells, and outlines problems yet to be resolved. The monolithic and mechanically stacked cells each have their own problems related to size, processing, current and voltage matching, weight, and other factors. More information is needed on the effect of temperature and radiation on the cell performance. Proper reference cells and full-spectrum range simulators are also needed to measure efficiencies correctly. Cost issues are not addressed, since the two approaches are still in the developmental stage.

Jain, Raj K.; Flood, Dennis J.

1992-01-01

364

Intracellular zinc is required for intestinal cell survival signals triggered by the inflammatory cytokine TNF?.  

PubMed

The essential micronutrient zinc has long been known to be a functional component of diverse structural proteins and enzymes. More recently, important roles for free or loosely bound intracellular zinc as a signaling factor have been reported. Insufficient zinc intake was shown to exacerbate symptoms in mouse models of inflammation such as experimental colitis, while zinc supplementation was found to improve intestinal barrier function. Herein, we provide evidence that intracellular zinc is essential for maintaining intestinal epithelial integrity when cells are exposed to the inflammatory cytokine Tumor Necrosis Factor (TNF)?. Using the human intestinal Caco-2/TC7 cell line as an in vitro model, we demonstrate that depletion of intracellular zinc affects TNF?-triggered signaling by shifting intestinal cell fate from survival to death. The mechanism underlying this effect was investigated. We show that TNF? promotes a zinc-dependent survival pathway that includes modulation of gene expression of transcription factors and signaling proteins. We have identified multiple regulatory steps regulated by zinc availability which include the induction of cellular Inhibitor of APoptosis (cIAP2) mRNA, possibly through activation of Nuclear Factor-Kappa B (NF-?B), as both nuclear translocation of the p65 subunit of NF-?B and up-regulation of cIAP2 mRNA were impaired following zinc depletion. Moreover, X-linked inhibitor of apoptosis protein level was profoundly reduced by zinc depletion. Our results provide a possible molecular explanation for the clinical observation that zinc supplements ameliorate Crohn's disease symptoms and decrease intestinal permeability in experimental colitis. PMID:22967671

Ranaldi, Giulia; Ferruzza, Simonetta; Canali, Raffaella; Leoni, Guido; Zalewski, Peter D; Sambuy, Yula; Perozzi, Giuditta; Murgia, Chiara

2013-06-01

365

Current and lattice matched tandem solar cell  

DOEpatents

A multijunction (cascade) tandem photovoltaic solar cell device is fabricated of a Ga.sub.x In.sub.1-x P (0.505.ltoreq.X.ltoreq.0.515) top cell semiconductor lattice matched to a GaAs bottom cell semiconductor at a low-resistance heterojunction, preferably a p+/n+ heterojunction between the cells. The top and bottom cells are both lattice matched and current matched for high efficiency solar radiation conversion to electrical energy.

Olson, Jerry M. (Lakewood, CO)

1987-01-01

366

Current status of silicon solar cell technology  

NASA Technical Reports Server (NTRS)

In quest of higher efficiency, major progress has occurred in solar cell technology. Cell efficiency has climbed about 50 percent. Technical approaches leading to increased output include back surface fields, shallow junctions, improved antireflection coatings, surface texturizing, and fine grid patterns on the cell surface. The status of current solar cell technology and its incorporation into cell production is discussed. Research and development leading to improved performance and reduced cost are also described.

Brandhorst, H. W., Jr.

1975-01-01

367

Front contact solar cell with formed emitter  

DOEpatents

A bipolar solar cell includes a backside junction formed by an N-type silicon substrate and a P-type polysilicon emitter formed on the backside of the solar cell. An antireflection layer may be formed on a textured front surface of the silicon substrate. A negative polarity metal contact on the front side of the solar cell makes an electrical connection to the substrate, while a positive polarity metal contact on the backside of the solar cell makes an electrical connection to the polysilicon emitter. An external electrical circuit may be connected to the negative and positive metal contacts to be powered by the solar cell. The positive polarity metal contact may form an infrared reflecting layer with an underlying dielectric layer for increased solar radiation collection.

Cousins, Peter John

2014-11-04

368

Front contact solar cell with formed emitter  

DOEpatents

A bipolar solar cell includes a backside junction formed by an N-type silicon substrate and a P-type polysilicon emitter formed on the backside of the solar cell. An antireflection layer may be formed on a textured front surface of the silicon substrate. A negative polarity metal contact on the front side of the solar cell makes an electrical connection to the substrate, while a positive polarity metal contact on the backside of the solar cell makes an electrical connection to the polysilicon emitter. An external electrical circuit may be connected to the negative and positive metal contacts to be powered by the solar cell. The positive polarity metal contact may form an infrared reflecting layer with an underlying dielectric layer for increased solar radiation collection.

Cousins, Peter John (Menlo Park, CA)

2012-07-17

369

Influence of zinc deficiency on cell-membrane fluidity in Jurkat, 3T3 and IMR-32 cells.  

PubMed Central

We investigated whether zinc deficiency can affect plasma membrane rheology. Three cell lines, human leukaemia T-cells (Jurkat), rat fibroblasts (3T3) and human neuroblastoma cells (IMR-32), were cultured for 48 h in control medium, in zinc-deficient medium (1.5 microM zinc; 1.5 Zn), or in the zinc-deficient medium supplemented with 15 microM zinc (15 Zn). The number of viable cells was lower in the 1.5 Zn group than in the control and 15 Zn groups. The frequency of apoptosis was higher in the 1.5 Zn group than in the control and 15 Zn groups. Membrane fluidity was evaluated using the 6-(9-anthroyloxy)stearic acid and 16-(9-anthroyloxy)palmitic acid probes. Membrane fluidity was higher in 1.5 Zn cells than in the control cells; no differences were observed between control cells and 15 Zn cells. The effect of zinc deficiency on membrane fluidity at the water/lipid interface was associated with a higher phosphatidylserine externalization. The higher membrane fluidity in the hydrophobic region of the bilayer was correlated with a lower content of arachidonic acid. We suggest that the increased fluidity of the membrane secondary to zinc deficiency is in part due to a decrease in arachidonic acid content and the apoptosis-related changes in phosphatidylserine distribution. PMID:14629198

Verstraeten, Sandra V; Zago, M Paola; MacKenzie, Gerardo G; Keen, Carl L; Oteiza, Patricia I

2004-01-01

370

New materials for solar cells - Tandem cells  

NASA Astrophysics Data System (ADS)

Cost efficiency in the manufacturing processes of the solar cell panels is discussed, noting the utilization of the III-V compound semiconductors (such as InSb or Ge) instead of silicon or gallium arsenide which have a complicated and expensive technology. A computation program is presented for a p-n junction using a set of nonlinear differential equations and taking into consideration such parameters as the mobility, the life space and the forbidden band. It is concluded that new, economic technologies should be directed toward blocking the UV light, acrylic elastomers, waterproof wood and paper materials and cost efficient silicon and fluorocarbon materials.

Dolocan, V.

371

CdS quantum-dot-sensitized Zn 2SnO 4 solar cell  

Microsoft Academic Search

The ternary oxide zinc stannate (Zn2SnO4) nanoparticles are first used as the electrode materials for the quantum dot sensitized solar cells. CdS quantum dots are utilized to sensitize Zn2SnO4 electrode via a chemical bath deposition technique. The covering of ZnS layer, the kinds of conducting substrates and the thickness of film are optimized to improve the cell performance. The optimal

Yafeng Li; Aiying Pang; Xiangzhen Zheng; Mingdeng Wei

2011-01-01

372

Method for processing silicon solar cells  

DOEpatents

The instant invention teaches a novel method for fabricating silicon solar cells utilizing concentrated solar radiation. The solar radiation is concentrated by use of a solar furnace which is used to form a front surface junction and back-surface field in one processing step. The present invention also provides a method of making multicrystalline silicon from amorphous silicon. The invention also teaches a method of texturing the surface of a wafer by forming a porous silicon layer on the surface of a silicon substrate and a method of gettering impurities. Also contemplated by the invention are methods of surface passivation, forming novel solar cell structures, and hydrogen passivation. 2 figs.

Tsuo, Y.S.; Landry, M.D.; Pitts, J.R.

1997-05-06

373

Method for processing silicon solar cells  

DOEpatents

The instant invention teaches a novel method for fabricating silicon solar cells utilizing concentrated solar radiation. The solar radiation is concentrated by use of a solar furnace which is used to form a front surface junction and back-surface field in one processing step. The present invention also provides a method of making multicrystallline silicon from amorphous silicon. The invention also teaches a method of texturing the surface of a wafer by forming a porous silicon layer on the surface of a silicon substrate and a method of gettering impurities. Also contemplated by the invention are methods of surface passivation, forming novel solar cell structures, and hydrogen passivation.

Tsuo, Y. Simon (Golden, CO); Landry, Marc D. (Lafayette, CO); Pitts, John R. (Lakewood, CO)

1997-01-01

374

Solar cell modules for plasma interaction evaluation  

NASA Technical Reports Server (NTRS)

A plasma interaction analysis in support of the solar electric propulsion subsystem examined the effects of a large high voltage solar array interacting with an ion thruster produced plasma. Two solar array test modules consisting of 36 large area wraparound contact solar cells welded to a flexible Kapton integrated circuit substrate were abricated. The modules contained certain features of the effects of insulation, din-holes, and bonding of the cell to the substrate and a ground plane. The possibility of a significant power loss occurring due to the collection of charged particles on the solar array interconnects was the focus of the research.

1981-01-01

375

Solar power satellites - Heat engine or solar cells  

NASA Technical Reports Server (NTRS)

A solar power satellite is the energy-converting element of a system that can deliver some 10 GW of power to utilities on the earth's surface. We evaluated heat engines and solar cells for converting sunshine to electric power at the satellite. A potassium Rankine cycle was the best of the heat engines, and 50 microns thick single-crystal silicon cells were the best of the photovoltaic converters. Neither solar cells nor heat engines had a clear advantage when all factors were considered. The potassium-turbine power plant, however, was more difficult to assemble and required a more expensive orbital assembly base. We therefore based our cost analyses on solar-cell energy conversion, concluding that satellite-generated power could be delivered to utilities for around 4 to 5 cents a kWh.

Oman, H.; Gregory, D. L.

1978-01-01

376

Coupling of Luminescent Solar Concentrators to Plasmonic Solar Cells  

NASA Astrophysics Data System (ADS)

To make inexpensive solar cells is a continuous goal for solar photovoltaic (PV) energy industry. Thin film solar cells of various materials have been developed and continue to emerge in order to replace bulk silicon solar cells. A thin film solar cell not only uses less material but also requires a less expensive refinery process. In addition, other advantages coming along with small thickness are higher open circuit voltage and higher conversion efficiency. However, thin film solar cells, especially those made of silicon, have significant optical losses. In order to address this problem, this thesis investigates the spectral coupling of thin films PV to luminescent solar concentrators (LSC). LSC are passive devices, consisting of plastic sheets embedded with fluorescent dyes which absorb part of the incoming radiation spectrum and emit at specific wavelength. The emitted light is concentrated by total internal reflection to the edge of the sheet, where the PVs are placed. Since the light emitted from the LSC edge is usually in a narrow spectral range, it is possible to employ diverse strategies to enhance PV absorption at the peak of the emission wavelength. Employing plasmonic nanostructures has been shown to enhance absorption of thin films via forward scattering, diffraction and localized surface plasmon. These two strategies are theoretically investigated here for improving the absorption and elevating the output power of a thin film solar cell. First, the idea of spectral coupling of luminescent solar concentrators to plasmonic solar cells is introduced to assess its potential for increasing the power output. This study is carried out employing P3HT/PC60BM organic solar cells and LSC with Lumogen Red dyes. A simplified spectral coupling analysis is employed to predict the power density, considering the output spectrum of the LSC equivalent to the emission spectrum of the dye and neglecting any angular dependence. Plasmonic tuning is conducted to enhance absorption at the emission peak of the dye. A factorial increase in the output power density of coupled PV as compared to PV exposed directly to solar spectrum is observed for high light concentration on the edge. These initial results motivated a more in-depth study of coupled LSC-PV system, which took into account the radiative transport inside the realistic LSC. These investigations were carried out on LSCs using Lumogen Red305 and Rhodamine 6G dyes coupled to pristine and plasmonic ultra-thin film silicon solar cells. Prediction based on detailed balance shows that the coupled LSC-plasmonic solar cell can generate 63.7 mW/cm2 with a photocurrent density of 71.3 mA/cm2 which is higher than that of cSi solar cells available on current market. The second part of the thesis focuses on PV absorption enhancement techniques. First, the effect of vertical positioning of plasmonic nanostructures on absorption enhancement was theoretically investigated to understand which one of the three mechanisms usually responsible for the enhancement (forward scattering, diffraction and localized surface plamson) plays the dominant role. Simulation results suggested that the maximum enhancement occurred when placing the nanostructures in the rear side of the cell because of longer path length due to scattering. The experimental effort then switched focus on substrate patterning, which is a less expensive alternative to plasmonic absorption enhancement. Specifically, a nanostructured substrate was prepared by a simple electrochemical process based on two-step aluminum anodization technique. The absorption of thin film silicon deposited on these substrates showed a broadband enhancement. The overall photocurrent density was up to 40% higher than that of films deposited on flat substrates. In conclusion, the studies carried out in this thesis indicate that spectral coupling of LSCs to thin film solar cells could lead to significant improvements in PV output power density. Moreover, while the absorption of thin film solar cells can be enhanced by plasmonic nanostructures, it is shown th

Wang, Shu-Yi

377

Temperature coefficients of multijunction solar cells  

Microsoft Academic Search

Temperatures coefficients measured in solar simulators with those measured under AM0 solar illumination are compared to illustrate the challenges in making these measurements. It is shown that simulator measurements of the short-circuit current (?JSC\\/?T) are inaccurate due to the mismatch between the solar spectrum and the simulators at the bandgaps of the solar cells. Especially susceptible to error is the

G. F. Virshup; B.-C. Chung; M. L. Ristow; M. S. Kuryla; D. Brinker

1990-01-01

378

Zinc deficiency in Mexican American children: influence of zinc and other micronutrients on T cells, cytokines, and antiinflammatory  

Microsoft Academic Search

Background: The Third National Health and Nutrition Examina- tion Survey suggested some Mexican American children are at risk of zinc deficiency. Objective:Wemeasuredtheeffectsofzincandmicronutrientsorof micronutrients alone on indexes of cell-mediated immunity and an- tiinflammatory plasma proteins. Design: Subjects (n 54) aged 6-7 y were randomly assigned and treated in double-blind fashion in equal numbers with 20 mg Zn (as sulfate) and micronutrients

Harold H Sandstead; Ananda S Prasad; James G Penland; Frances WJ; Joseph Kaplan Beck; Norman G Egger; Nancy W Alcock; Richard M Carroll; VMS Ramanujam; Hari H Dayal; Carmen D Rocco; Ruth Ann Plotkin; Antonio N Zavaleta

379

Sensitized energy transfer for organic solar cells, optical solar concentrators, and solar pumped lasers  

E-print Network

The separation of chromophore absorption and excitonic processes, such as singlet exciton fission and photoluminescence, offers several advantages to the design of organic solar cells and luminescent solar concentrators ...

Reusswig, Philip David

2014-01-01

380

Expression analysis of zinc transporters in resting and stimulated human peripheral blood mononuclear cells  

PubMed Central

Intracellular zinc homeostasis is tightly regulated under physiological conditions; however, dysregulation of zinc levels has been reported in various chronic inflammatory and malignant diseases. In this study, we aimed to assess the expression pattern of the 24 currently known zinc transporters in resting and stimulated human peripheral blood mononuclear cells (PBMCs). The cells were isolated from healthy probands and subsequently stimulated with phytohaemagglutinin (PHA) for 3 days. The expression levels of zinc transporters [Zrt/IRT-like protein (ZIP) and cation diffusion facilitator/zinc transporter protein (CDF/ZnT) families] were analyzed by quantitative reverse transcription-polymerase chain reaction. Of the 24 genes encoding for zinc transporters, 19 were found to be ubiquitously expressed in PBMCs. ZIP5 and ZnT10 were not found in all 5 samples, whereas ZIP12, ZnT3 and ZIP2 were expressed in only 12 out of 5 PBMC samples. Of note, stimulation by PHA led to an overall downregulation of zinc transporters in the PBMCs of 4 out of the 5 subjects. Notably, the transcript levels of ZIP14 were consistently induced and those of ZIP3 and ZIP4 consistently downregulated in all 5 subjects, whereas the corresponding levels of the remaining 21 genes varied. Data from this study may facilitate a better understanding of the pathophysiological role of deregulated zinc transporters in chronic inflammatory diseases. PMID:24649099

WEX, THOMAS; GRUNGREIFF, KURT; SCHUTTE, KERSTIN; STENGRITT, MAREN; REINHOLD, DIRK

2014-01-01

381

Boron phosphide under pressure: In situ study by Raman scattering and X-ray diffraction  

SciTech Connect

Cubic boron phosphide, BP, has been studied in situ by X-ray diffraction and Raman scattering up to 55?GPa at 300?K in a diamond anvil cell. The bulk modulus of B{sub 0}?=?174(2) GPa has been established, which is in excellent agreement with our ab initio calculations. The data on Raman shift as a function of pressure, combined with equation-of-state (EOS) data, allowed us to estimate the Grneisen parameters of the TO and LO modes of zinc-blende structure, ?{sub G}{sup TO?}=?1.26 and ?{sub G}{sup LO?}=?1.13, just like in the case of other A{sup III}B{sup V} diamond-like phases, for which ?{sub G}{sup TO?}>??{sub G}{sup LO?}??1. We also established that the pressure dependence of the effective electro-optical constant ? is responsible for a strong change in relative intensities of the TO and LO modes from I{sub TO}/I{sub LO}???0.25 at 0.1?MPa to I{sub TO}/I{sub LO}???2.5 at 45?GPa, for which we also find excellent agreement between experiment and theory.

Solozhenko, Vladimir L. [LSPMCNRS, Universit Paris Nord, 93430 Villetaneuse (France); Kurakevych, Oleksandr O.; Le Godec, Yann [IMPMC, UPMC Sorbonne Universits, UMR CNRS 7590, Musum National d'Histoire Naturelle, IRD UMR 206, 75005 Paris (France); Kurnosov, Aleksandr V. [Bayerisches Geoinstitut, Universitt Bayreuth, 95440 Bayreuth (Germany); Oganov, Artem R. [Department of Geosciences, Center for Materials by Design, Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794-2100 (United States)

2014-07-21

382

Oxide and sulfide semiconductor thin films for solar cells and spintronic devices  

NASA Astrophysics Data System (ADS)

This dissertation will present the synthesis and characterization of the doped-zinc oxide (ZnO) thin films deposited by various techniques for their potential applications in spintronics devices and solar cells. The research work shows room temperature ferromagnetism in transition metal doped zinc oxide dilute magnetic semiconductors in highly crystalline nanostructured and polycrystalline forms. A spin field effect transistor working as a resistive switch was simulated based on the conductance modulation of the electron channel formed by magnetic impurity doped ZnO. Light scattering properties of nanostructured doped ZnO films has been simulated using Mie scattering theory in view of possible application in light harvesting in solar cells. Band gap bowing effect was achieved in sulfur-alloyed ZnO (zinc oxysulfide) films and a new bowing parameter and stress effect gave a better understanding of the sulfur alloyed effect in these polycrystalline thin films synthesized by chemical spray pyrolysis technique. A novel nanostructure was developed with sulfur-doping of ZnO in the ZnO core and zinc oxysulfide (ZnO1-xSx) shell form. For the first time the ZnO-ZnO1-xSx core-shell nanorods were applied to develop 3-dimenstional organic-inorganic hybrid solar cells. The performance of organic-inorganic hybrid solar cells based on ZnO-ZnO 1-xSx core-shell nanorods thin films was evaluated using the current-voltage characteristics. Further, the role of flux induced crystallization of Cu2ZnSnS4 (CZTS) thin films by chemical spray pyrolysis technique is explored. This dissertation also investigates the interface effects and heterojunction properties of cadmium sulfide/CZTS heterojunction solar cells.

Ramachandran Thankalekshmi, Ratheesh

383

Zinc transferrin stimulates red blood cell formation in the head kidney of common carp (Cyprinus carpio).  

PubMed

The common carp is one of the few fish able to tolerate extremely low oxygen levels. These fish store zinc in their digestive tract tissue and head kidney at concentrations of 300-500?g/g of fresh tissue, which is 5-10 times higher than in other fish. Previous studies have indicated a link between the high zinc levels in the common carp and stress erythropoiesis. In this report, using suspension-cultured common carp head kidney cells with or without ZnCl2 supplementation, we found that zinc stimulated the proliferation of immature red blood cells; however, this effect was only observed when the culture was supplemented with carp serum. We identified the active component of carp serum to be transferrin. The zinc-transferrin complex interacts with the transferrin receptor and stimulates the proliferation of immature red blood cells. In addition, the growth rate of the immature red blood cells was regulated by the supplied ZnCl2 concentration. Under stress, the zinc in the common carp digestive tract tissue was released and used as a signal to induce red blood cell formation in the head kidney. This cell culture system might provide a means for exploring the regulatory role of zinc in hematopoietic cell growth. PMID:23665074

Chen, Yen-Hua; Fang, Szu-Wei; Jeng, Sen-Shyong

2013-09-01

384

Si concentrator solar cell development. [Final report  

SciTech Connect

This is the final report of a program to develop a commercial, high-efficiency, low-cost concentrator solar cell compatible with Spectrolab`s existing manufacturing infrastructure for space solar cells. The period covered is between 1991 and 1993. The program was funded through Sandia National Laboratories through the DOE concentrator initiative and, was also cost shared by Spectrolab. As a result of this program, Spectrolab implemented solar cells achieving an efficiency of over 19% at 200 to 300X concentration. The cells are compatible with DOE guidelines for a cell price necessary to achieve a cost of electricity of 12 cents a kilowatthour.

Krut, D.D. [Spectrolab, Inc., Sylmar, CA (United States)

1994-10-01

385

Epitaxial silicon growth for solar cells  

NASA Technical Reports Server (NTRS)

Growth and fabrication procedures for the baseline solar cells are described along with measured cell parameters, and the results. Reproducibility of these results was established and the direction to be taken for higher efficiency is identified.

Daiello, R. V.; Robinson, P. H.; Richman, D.

1978-01-01

386

Monolithic cascade-type solar cells  

NASA Technical Reports Server (NTRS)

Solar cells consist of a semiconductor base, a bottom cell with a band-gap energy of E1, and a top cell with a band-gap energy of E2, and 0.96 E1 1.36 eV and (0.80 E + 0.77) eV E2 (0.80 E1 + 0.92) eV. A monolithic cascade-type solar cell was prepared with an n(+)-type GaAs base, a GaInAs bottom solar cell, and a GaAiInAs top solar cell. The surface of the cell is coated with a SiO antireflection film. The efficiency of the cell is 32%.

Yamamoto, S.; Shibukawa, A.; Yamaguchi, M.

1985-01-01

387

Monolithic cascade-type solar cells  

SciTech Connect

Solar cells consist of a semiconductor base, a bottom cell with a band-gap energy of E1, and a top cell with a band-gap energy of E2, and 0.96 E1 1.36 eV and (0.80 E + 0.77) eV E2 (0.80 E1 + 0.92) eV. A monolithic cascade-type solar cell was prepared with an n(+)-type GaAs base, a GaInAs bottom solar cell, and a GaAiInAs top solar cell. The surface of the cell is coated with a SiO antireflection film. The efficiency of the cell is 32%.

Yamamoto, S.; Shibukawa, A.; Yamaguchi, M.

1985-12-01

388

Monolithic cells for solar fuels.  

PubMed

Hybrid energy generation models based on a variety of alternative energy supply technologies are considered the best way to cope with the depletion of fossil energy resources and to limit global warming. One of the currently missing technologies is the mimic of natural photosynthesis to convert carbon dioxide and water into chemical fuel using sunlight. This idea has been around for decades, but artificial photosynthesis of organic molecules is still far away from providing real-world solutions. The scientific challenge is to perform in an efficient way the multi-electron transfer reactions of water oxidation and carbon dioxide reduction using holes and single electrons generated in an illuminated semiconductor. In this tutorial review the design of photoelectrochemical (PEC) cells that combine solar water oxidation and CO2 reduction is discussed. In such PEC cells simultaneous transport and efficient use of light, electrons, protons and molecules has to be managed. It is explained how efficiency can be gained by compartmentalisation of the water oxidation and CO2 reduction processes by proton exchange membranes, and monolithic concepts of artificial leaves and solar membranes are presented. Besides transferring protons from the anode to the cathode compartment the membrane serves as a molecular barrier material to prevent cross-over of oxygen and fuel molecules. Innovative nano-organized multimaterials will be needed to realise practical artificial photosynthesis devices. This review provides an overview of synthesis techniques which could be used to realise monolithic multifunctional membrane-electrode assemblies, such as Layer-by-Layer (LbL) deposition, Atomic Layer Deposition (ALD), and porous silicon (porSi) engineering. Advances in modelling approaches, electrochemical techniques and in situ spectroscopies to characterise overall PEC cell performance are discussed. PMID:24526085

Rong, Jan; Bosserez, Tom; Martel, David; Nervi, Carlo; Boarino, Luca; Taulelle, Francis; Decher, Gero; Bordiga, Silvia; Martens, Johan A

2014-12-01

389

Double-sided solar cell package  

NASA Technical Reports Server (NTRS)

In a solar cell array of terrestrial use, an improved double-sided solar cell package, consisting of a photovoltaic cell having a metallized P-contact strip and an N-contact grid, provided on opposite faces of the cell, a transparent tubular body forming an enclosure for the cell. A pedestal supporting the cell from within the enclosure comprising an electrical conductor connected with the P-contact strip provided for each face of the cell, and a reflector having an elongated reflective surface disposed in substantially opposed relation with one face of the cell for redirecting light were also included.

Shelpuk, B. (inventor)

1979-01-01

390

Zip4 Mediated Zinc Influx Stimulates Insulin Secretion in Pancreatic Beta Cells  

PubMed Central

Zinc has an important role in normal pancreatic beta cell physiology as it regulates gene transcription, insulin crystallization and secretion, and cell survival. Nevertheless, little is known about how zinc is transported through the plasma membrane of beta cells and which of the class of zinc influx transporters (Zip) is involved. Zip4 was previously shown to be expressed in human and mouse beta cells; however, its function there is still unknown. Therefore, the aim of this study was to define the zinc transport role of Zip4 in beta cells. To investigate this, Zip4 was over-expressed in MIN6 beta cells using a pCMV6-Zip4GFP plasmid. Organelle staining combined with confocal microscopy showed that Zip4 exhibits a widespread localization in MIN6 cells. Time-lapse zinc imaging experiments showed that Zip4 increases cytoplasmic zinc levels. This resulted in increased granular zinc content and glucose-stimulated insulin secretion. Interestingly, it is unlikely that the increased glucose stimulated insulin secretion was triggered by a modulation of mitochondrial function, as mitochondrial membrane potential remained unchanged. To define the role of Zip4 in-vivo, we generated a beta cell-specific knockout mouse model (Zip4BKO). Deletion of the Zip4 gene was confirmed in Zip4BKO islets by PCR, RT-PCR, and immuno-histochemistry. Zip4BKO mice showed slightly improved glucose homeostasis but no change in insulin secretion during an oral glucose tolerance test. While Zip4 was not found to be essential for proper glucose homeostasis and insulin secretion in vivo in mice, this study also found that Zip4 mediates increases in cytoplasmic and granular zinc pools and stimulates glucose dependant insulin secretion in-vitro. PMID:25806541

Hardy, Alexandre B.; Prentice, Kacey J.; Froese, Sean; Liu, Ying; Andrews, Glen K.; Wheeler, Michael B.

2015-01-01

391

Operating characteristics of multijunction solar cells  

Microsoft Academic Search

Multijunction solar cells produced by Spectrolab are the most efficient solar cells in the world, with a record efficiency of over 40%. Cell designs have been modified for high performance in concentrator photovoltaic (CPV) systems with the potential for low-cost, high-volume manufacturing. High-performance CPV cells have been designed, tested, and entered into production for field testing in CPV systems. Performance

Geoffrey S. Kinsey; Peichen Pien; Peter Hebert; Raed A. Sherif

2009-01-01

392

(Melanin-Sensitized Solar Cell) : 696220016  

E-print Network

(Melanin-Sensitized Solar Cell) : : : 696220016 #12; #12;#12; #12;I PLD-sensitized solar cell use. In order to improve such question, this research used the melanin which the human body and the most biology had to regard the dye to catch the photon.The melanin met several requirements

393

Introduction to basic solar cell measurements  

NASA Technical Reports Server (NTRS)

The basic approaches to solar cell performance and diagnostic measurements are described. The light sources, equipment for I-V curve measurement, and the test conditions and procedures for performance measurement are detailed. Solar cell diagnostic tools discussed include analysis of I-V curves, series resistance and reverse saturation current determination, spectral response/quantum yield measurement, and diffusion length/lifetime determination.

Brandhorst, H. W., Jr.

1976-01-01

394

EE580 Solar Cells Todd J. Kaiser  

E-print Network

7/21/2010 1 EE580 ­ Solar Cells Todd J. Kaiser · Lecture 03 · Nature of Sunlight 1Montana State University: Solar Cells Lecture 3: Nature of Sunlight Wave-Particle Duality · Light acts as ­ Waves: photons ­ individual packets of energy · Photoelectric Effect · Blackbody Radiation 2Montana State

Kaiser, Todd J.

395

Analyzing free zinc(II) ion concentrations in cell biology with fluorescent chelating molecules.  

PubMed

Essential metal ions are tightly controlled in biological systems. An understanding of metal metabolism and homeostasis is being developed from quantitative information of the sizes, concentrations, and dynamics of cellular and subcellular metal ion pools. In the case of human zinc metabolism, minimally 24 proteins of two zinc transporter families and a dozen metallothioneins participate in cellular uptake, extrusion, and re-distribution among cellular compartments. Significantly, zinc(ii) ions are now considered signaling ions in intra- and intercellular communication. Such functions require transients of free zinc ions. It is experimentally quite challenging to distinguish zinc that is protein-bound from zinc that is not bound to proteins. Measurement of total zinc is relatively straightforward with analytical techniques such as atomic absorption/emission spectroscopy or inductively coupled plasma mass spectrometry. Total zinc concentrations of human cells are 200-300 ?M. In contrast, the pool of non-protein bound zinc is mostly examined with fluorescence microscopy/spectroscopy. There are two widely applied fluorescence approaches, one employing low molecular weight chelating agents ("probes") and the other metal-binding proteins ("sensors"). The protein sensors, such as the CALWY, Zap/ZifCY, and carbonic anhydrase-based sensors, can be genetically encoded and have certain advantages in terms of controlling intracellular concentration, localization, and calibration. When employed correctly, both probes and sensors can establish qualitative differences in free zinc ion concentrations. However, when quantitative information is sought, the assumptions underlying the applications of probes and sensors must be carefully examined and even then measured pools of free zinc ions remain methodologically defined. A consensus is building that the steady-state free zinc ion concentrations in the cytosol are in the picomolar range but there is no consensus on their concentrations in subcellular compartments. Applying the extensive toolbox of available probes/sensors in biological systems requires an understanding of the principles of cellular zinc homeostasis and the chemical biology of the probes and sensors. Regardless of limitations in specificity (for a particular metal ion), selectivity (for a particular metal pool), and sensitivity (detection limit), the technology is making remarkable contributions to imaging zinc with high spatiotemporal resolution in single cells and to defining the biochemical functions of zinc ions in cellular regulation. PMID:25362967

Maret, Wolfgang

2015-02-01

396

Gettered GaP Substrates for Improved Multijunction Solar Cell Devices  

Microsoft Academic Search

We report on the characterization of gettered p-type GaP substrates for application in high-efficiency multijunction solar cells. A commercial zinc-doped GaP substrate was divided, with one piece soaked in a phosphorus-saturated gallium-aluminum melt at 975C. Low-temperature continuous-wave photoluminescence indicated a significant decrease in deep-level impurity peaks due to oxygen and zinc-oxygen complexes after gettering in the phosphorus-saturated gallium-aluminum melt. To

K. H. Montgomery; C. R. Allen; I. H. Wildeson; J.-H. Jeon; A. K. Ramdas; J. M. Woodall

2011-01-01

397

Gettered GaP Substrates for Improved Multijunction Solar Cell Devices  

Microsoft Academic Search

We report on the characterization of gettered p-type GaP substrates for application in high-efficiency multijunction solar cells. A commercial zinc-doped GaP substrate was\\u000a divided, with one piece soaked in a phosphorus-saturated gallium-aluminum melt at 975C. Low-temperature continuous-wave photoluminescence\\u000a indicated a significant decrease in deep-level impurity peaks due to oxygen and zinc-oxygen complexes after gettering in the\\u000a phosphorus-saturated gallium-aluminum melt. To

K. H. Montgomery; C. R. Allen; I. H. Wildeson; J.-H. Jeon; A. K. Ramdas; J. M. Woodall

2011-01-01

398

Epitaxial silicon growth for solar cells  

NASA Technical Reports Server (NTRS)

The epitaxial procedures, solar cell fabrication, and evaluation techniques are described. The development of baseline epitaxial solar cell structures grown on high quality conventional silicon substrates is discussed. Diagnostic layers and solar cells grown on four potentially low cost silicon substrates are considered. The crystallographic properties of such layers and the performance of epitaxially grown solar cells fabricated on these materials are described. An advanced epitaxial reactor, the rotary disc, is described along with the results of growing solar cell structures of the baseline type on low cost substrates. The add on cost for the epitaxial process is assessed and the economic advantages of the epitaxial process as they relate to silicon substrate selection are examined.

Daiello, R. V.; Robinson, P. H.; Richman, D.

1979-01-01

399

Planar multijunction high voltage solar cells  

NASA Technical Reports Server (NTRS)

Technical considerations, preliminary results, and fabrication details are discussed for a family of high-voltage planar multi-junction (PMJ) solar cells which combine the attractive features of planar cells with conventional or interdigitated back contacts and the vertical multijunction (VMJ) solar cell. The PMJ solar cell is internally divided into many voltage-generating regions, called unit cells, which are internally connected in series. The key to obtaining reasonable performance from this device was the separation of top surface field regions over each active unit cell. Using existing solar cell fabricating methods, output voltages in excess of 20 volts per linear centimeter are possible. Analysis of the new device is complex, and numerous geometries are being studied which should provide substantial benefits in both normal sunlight usage as well as with concentrators.

Evans, J. C., Jr.; Chai, A. T.; Goradia, C.

1980-01-01

400

Silicon film solar cell process  

NASA Technical Reports Server (NTRS)

The most promising way to reduce the cost of silicon in solar cells while still maintaining performance is to utilize thin films (10 to 20 microns thick) of crystalline silicon. The method of solution growth is being employed to grow thin polycrystalline films of silicon on dissimilar substrates. The initial results indicate that, using tin as the solvent, this growth process only requires operating temperatures in the range of 800 C to 1000 C. Growth rates in the range of 0.4 to 2.0 microns per minute and grain sizes in the range of 20 to 100 microns were achieved on both quartz and coated steel substrates. Typically, an aspect ratio of two to three between the width and the Si grain thickness is seen. Uniform coverage of Si growth on quartz over a 2.5 x 2.5 cm area was observed.

Hall, R. B.; Mcneely, J. B.; Barnett, A. M.

1984-01-01

401

Development of IBC solar cells  

NASA Astrophysics Data System (ADS)

The IBC solar cell has shown itself to be promising for concentrator applications. However, the optimum finger-width ratio has not been established and it would be useful to know whether passivation of the metallic contact areas using oxide or polysilicon would be a practical way of improving open circuit voltage. The use of IC technology with test structures to determine bulk lifetime, SRV, mobility and contact resistance would test the above possibilities and the correctness of the theoretical analysis. Initial results have that the optimum finger-width ratio is 4:1 and that the test structures provide consistent data on the parameters listed above, as well as bulk resistivity and diffused layer sheet resistances.

Parrott, J. E.; Elani, U.

402

High-Temperature Solar Cell Development  

NASA Technical Reports Server (NTRS)

The vast majority of satellites and near-earth probes developed to date have relied upon photovoltaic power generation. If future missions to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. For example, the equilibrium temperature of a Mercury surface station will be about 450 C, and the temperature of solar arrays on the proposed "Solar Probe" mission will extend to temperatures as high as 2000 C (although it is likely that the craft will operate on stored power rather than solar energy during the closest approach to the sun). Advanced thermal design principles, such as replacing some of the solar array area with reflectors, off-pointing, and designing the cells to reflect rather than absorb light out of the band of peak response, can reduce these operating temperature somewhat. Nevertheless, it is desirable to develop approaches to high-temperature solar cell design that can operate under temperature extremes far greater than today's cells. Solar cells made from wide bandgap (WBG) compound semiconductors are an obvious choice for such an application. In order to aid in the experimental development of such solar cells, we have initiated a program studying the theoretical and experimental photovoltaic performance of wide bandgap materials. In particular, we have been investigating the use of GaP, SiC, and GaN materials for space solar cells. We will present theoretical results on the limitations on current cell technologies and the photovoltaic performance of these wide-bandgap solar cells in a variety of space conditions. We will also give an overview of some of NASA's cell developmental efforts in this area and discuss possible future mission applications.

Landis, Geoffrey A.; Raffaelle, Ryne P.; Merritt, Danielle

2004-01-01

403

Coating Processes Boost Performance of Solar Cells  

NASA Technical Reports Server (NTRS)

NASA currently has spacecraft orbiting Mercury (MESSENGER), imaging the asteroid Vesta (Dawn), roaming the red plains of Mars (the Opportunity rover), and providing a laboratory for humans to advance scientific research in space (the International Space Station, or ISS). The heart of the technology that powers those missions and many others can be held in the palm of your hand - the solar cell. Solar, or photovoltaic (PV), cells are what make up the panels and arrays that draw on the Sun s light to generate electricity for everything from the Hubble Space Telescope s imaging equipment to the life support systems for the ISS. To enable NASA spacecraft to utilize the Sun s energy for exploring destinations as distant as Jupiter, the Agency has invested significant research into improving solar cell design and efficiency. Glenn Research Center has been a national leader in advancing PV technology. The Center s Photovoltaic and Power Technologies Branch has conducted numerous experiments aimed at developing lighter, more efficient solar cells that are less expensive to manufacture. Initiatives like the Forward Technology Solar Cell Experiments I and II in which PV cells developed by NASA and private industry were mounted outside the ISS have tested how various solar technologies perform in the harsh conditions of space. While NASA seeks to improve solar cells for space applications, the results are returning to Earth to benefit the solar energy industry.

2012-01-01

404

Alveolar Epithelial Cell Injury Due to Zinc Oxide Nanoparticle Exposure  

PubMed Central

Rationale: Although inhalation of zinc oxide (ZnO) nanoparticles (NPs) is known to cause systemic disease (i.e., metal fume fever), little is known about mechanisms underlying injury to alveolar epithelium. Objectives: Investigate ZnO NPinduced injury to alveolar epithelium by exposing primary cultured rat alveolar epithelial cell monolayers (RAECMs) to ZnO NPs. Methods: RAECMs were exposed apically to ZnO NPs or, in some experiments, to culture fluid containing ZnCl2 or free Zn released from ZnO NPs. Transepithelial electrical resistance (RT) and equivalent short-circuit current (IEQ) were assessed as functions of concentration and time. Morphologic changes, lactate dehydrogenase release, cell membrane integrity, intracellular reactive oxygen species (ROS), and mitochondrial activity were measured. Measurements and Main Results: Apical exposure to 176 ?g/ml ZnO NPs decreased RT and IEQ of RAECMs by 100% over 24 hours, whereas exposure to 11 ?g/ml ZnO NPs had little effect. Changes in RT and IEQ caused by 176 ?g/ml ZnO NPs were irreversible. ZnO NP effects on RT yielded half-maximal concentrations of approximately 20 ?g/ml. Apical exposure for 24 hours to 176 ?g/ml ZnO NPs induced decreases in mitochondrial activity and increases in lactate dehydrogenase release, permeability to fluorescein sulfonic acid, increased intracellular ROS, and translocation of ZnO NPs from apical to basolateral fluid (most likely across injured cells and/or damaged paracellular pathways). Conclusions: ZnO NPs cause severe injury to RAECMs in a dose- and time-dependent manner, mediated, at least in part, by free Zn released from ZnO NPs, mitochondrial dysfunction, and increased intracellular ROS. PMID:20639441

Kim, Yong Ho; Fazlollahi, Farnoosh; Kennedy, Ian M.; Yacobi, Nazanin R.; Hamm-Alvarez, Sarah F.; Borok, Zea; Kim, Kwang-Jin; Crandall, Edward D.

2010-01-01

405

Silicon solar cell efficiency - Practice and promise.  

NASA Technical Reports Server (NTRS)

The maximum efficiency of silicon solar cells is calculated and yields a value near 18%. Additionally, the performance of these high efficiency cells in a synchronous orbit radiation field is calculated and indicates that these cells would be superior to present silicon cells at all times. The performance of conventional cells is analyzed and several areas in which performance gains may be achieved are discussed. These areas include improvements in diffused region profile, in reduction of excess forward currents in cells made from low resistivity material and in the theory for describing complex solar cell structures.

Brandhorst, H. W., Jr.

1972-01-01

406

Silicon solar cell efficiency: Practice and promise  

NASA Technical Reports Server (NTRS)

The maximum efficiency of silicon solar cells was calculated and yielded a value near 18%. Additionally, the performance of these high efficiency cells in a synchronous orbit radiation field was calculated and it is suggested that these cells would be superior to present silicon cells. The performance of conventional cells was analyzed and several areas in which performance gains may be achieved are discussed. These areas include improvements in diffused region profile, in reduction of excess forward currents in cells made from low resistivity material, and in the theory for describing complex solar cell structures.

Brandhorst, H. W., Jr.

1972-01-01

407

Zinc(II)-Coordinated Oligotyrosine: A New Class of Cell Penetrating James R. Johnson, Hua Jiang, and Bradley D. Smith*  

E-print Network

Zinc(II)-Coordinated Oligotyrosine: A New Class of Cell Penetrating Peptide James R. Johnson, Hua with a zinc (II) cation. This in turn allows reversible association with a chelating oxyanion- lylamine unit that forms a stable coordination complex with a zinc (II) cation (Scheme 1) (25). Previously

Smith, Bradley D.

408

Tandem photovoltaic solar cells and increased solar energy conversion efficiency  

NASA Technical Reports Server (NTRS)

Tandem photovoltaic cells, as proposed by Jackson (1955) to increase the efficiency of solar energy conversion, involve the construction of a system of stacked p/n homojunction photovoltaic cells composed of different semiconductors. It had been pointed out by critics, however, that the total power which could be extracted from the cells in the stack placed side by side was substantially greater than the power obtained from the stacked cells. A reexamination of the tandem cell concept in view of the development of the past few years is conducted. It is concluded that the use of tandem cell systems in flat plate collectors, as originally envisioned by Jackson, may yet become feasible as a result of the development of economically acceptable solar cells for large scale terrestrial power generation.

Loferski, J. J.

1976-01-01

409

Esophagobronchial fistula - A rare complication of aluminum phosphide poisoning.  

PubMed

Aluminum phosphide is a systemic lethal poison. Fistulous communication between esophagus and airway tract (esophagorespiratory fistula) has rarely been reported in the survivors of aluminum phosphide poisoning. We report a case of benign esophagobronchial fistula secondary to aluminum phosphide poisoning, which to best of our knowledge has not been reported in the medical literature. PMID:21264171

Bhargava, Sumeet; Rastogi, Rajul; Agarwal, Ajay; Jindal, Gaurav

2011-01-01

410

Indium Phosphide Planar Integrated Optics Comes of Age Jens Noeckel  

E-print Network

Indium Phosphide Planar Integrated Optics Comes of Age Jens Noeckel Tom Pierson Jane Zucker exceeds supply. Indium Phosphide: Adapting Form to Function PLCs can serve many roles in fiberoptic of the spectrum, the current material of choice is indium phosphide. When compared with the sophistication

Nckelm, Jens

411

Anti-inflammatory effects of zinc in PMA-treated human gingival fibroblast cells  

PubMed Central

Objectives: Abnormal cellular immune response has been considered to be responsible for oral lesions in recurrent aphthous stomatitis. Zinc has been known to be an essential nutrient metal that is necessary for a broad range of biological activities including antioxidant, immune mediator, and anti-inflammatory drugs in oral mucosal disease. The objective of this study was to investigate the effects of zinc in a phorbol-12-myristate-13-acetate (PMA)-treated inflammatory model on human gingival fibroblast cells (hGFs). Study Design: Cells were pre-treated with zinc chloride, followed by PMA in hGFs. The effects were assessed on cell viability, cyclooxygenease-1,2(COX-1/2) protein expression, PGE2 release, ROS production and cytokine release, Results: The effects were assessed on cell viability, COX1/2 protein expression, PGE2 release, ROS production, cytokine release. The results showed that, in the presence of PMA, zinc treatment leads to reduce the production of ROS, which results in decrease of COX-2 expression and PGE2 release. Conclusions: Thus, we suggest that zinc treatment leads to the mitigation of oral inflammation and may prove to be an alternative treatment for recurrent aphthous stomatitis. Key words:Zinc, inflammatory response, cytokines, phorbol-12-myristate-13-acetate, gingival fibroblasts cells. PMID:25662537

Kim, Sangwoo; Jeon, Sangmi; Hui, Zheng; Kim, Young; Im, Yeonggwan; Lim, Wonbong; Kim, Changsu; Choi, Hongran; Kim, Okjoon

2015-01-01

412

Method for identifying neuronal cells suffering zinc toxicity by use of a novel fluorescent sensor.  

PubMed

During excitotoxic brain damage, injured neurons accumulate an anomalous, pathological burden of weakly bound, rapidly exchangeable Zn(2+) that diffusely fills the soma, nucleus and proximal dendrites. Mounting evidence indicates that this Zn(2+) is a major contributing factor in the subsequent demise of the damaged neurons. Thus, identifying, imaging, and characterizing zinc-filled cells have become essential steps in understanding excitotoxicity. Here we demonstrate that a new fluorescent stain for zinc can rather selectively and quite vividly label zinc-filled neurons in frozen histologic sections. The method is more sensitive and selective than the existing stain TSQ, and simpler than the Timm-Danscher silver staining techniques. A previously unobserved population of apparently injured cells in the dentate gyrus has been discovered with the new reagent. Whereas cells viewed in situ in normal, healthy tissue virtually never display any perikaryal staining by histochemical methods for zinc, injured cells stain intensely for zinc in culture, acute slice preparations and in tissue harvested in vivo. Thus, the presence of rapidly-exchangeable, "stainable" perikaryal zinc may be taken as an indicator of cell injury. PMID:15351524

Frederickson, Christopher J; Burdette, Shawn C; Frederickson, Cathy J; Sensi, Stefano L; Weiss, John H; Yin, Hong Z; Balaji, Rengarajan V; Truong-Tran, Ai Q; Bedell, Eric; Prough, Donald S; Lippard, Stephen J

2004-10-15

413

Ethambutol-induced toxicity is mediated by zinc and lysosomal membrane permeabilization in cultured retinal cells  

SciTech Connect

Ethambutol, an efficacious antituberculosis agent, can cause irreversible visual loss in a small but significant fraction of patients. However, the mechanism of ocular toxicity remains to be established. We previously reported that ethambutol caused severe vacuole formation in cultured retinal cells, and that the addition of zinc along with ethambutol aggravated vacuole formation whereas addition of the cell-permeable zinc chelator, N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN), reduced vacuole formation. To investigate the origin of vacuoles and to obtain an understanding of drug toxicity, we used cultured primary retinal cells from newborn Sprague-Dawley rats and imaged ethambutol-treated cells stained with FluoZin-3, zinc-specific fluorescent dye, under a confocal microscope. Almost all ethambutol-induced vacuoles contained high levels of labile zinc. Double staining with LysoTracker or MitoTracker revealed that almost all zinc-containing vacuoles were lysosomes and not mitochondria. Intracellular zinc chelation with TPEN markedly blocked both vacuole formation and zinc accumulation in the vacuole. Immunocytochemistry with antibodies to lysosomal-associated membrane protein-2 (LAMP-2) and cathepsin D, an acid lysosomal hydrolase, disclosed lysosomal activation after exposure to ethambutol. Immunoblotting after 12 h exposure to ethambutol showed that cathepsin D was released into the cytosol. In addition, cathepsin inhibitors attenuated retinal cell toxicity induced by ethambutol. This is consistent with characteristics of lysosomal membrane permeabilization (LMP). TPEN also inhibited both lysosomal activation and LMP. Thus, accumulation of zinc in lysosomes, and eventual LMP, may be a key mechanism of ethambutol-induced retinal cell death.

Chung, Hyewon; Yoon, Young Hee [Department of Ophthalmology, Asan Medical Center, University of Ulsan, College of Medicine, 388-1 Pungnab-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Hwang, Jung Jin [Institute for Innovative Cancer Research, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Cho, Kyung Sook [Department of Ophthalmology, Asan Medical Center, University of Ulsan, College of Medicine, 388-1 Pungnab-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Koh, Jae Young [NRL Neural Injury Research Center and the Department of Neurology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Kim, June-Gone [Department of Ophthalmology, Asan Medical Center, University of Ulsan, College of Medicine, 388-1 Pungnab-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of)], E-mail: junekim@amc.seoul.kr

2009-03-01

414

Human fetal endothelial cells acquire Zinc(II) from both the protein bound and nonprotein bound pools in serum  

Microsoft Academic Search

To help determine physiologically important routes by which zinc (Zn) is acquired by human fetal vascular endothelium, the\\u000a authors incubated cultured umbilical vein endothelial cells with65Zn(II)-tracer labeled human fetal whole serum, ultrafiltrate (containing low molecular mass serum zinc complexes), and dialyzed\\u000a serum (containing protein-bound zinc). Zinc from whole serum and from both serum fractions entered a rapidly labeled cellular\\u000a compartment

Christopher M. R. Bax; David L. Bloxam

1997-01-01

415

Semiconductor quantum dot-sensitized solar cells  

PubMed Central

Semiconductor quantum dots (QDs) have been drawing great attention recently as a material for solar energy conversion due to their versatile optical and electrical properties. The QD-sensitized solar cell (QDSC) is one of the burgeoning semiconductor QD solar cells that shows promising developments for the next generation of solar cells. This article focuses on recent developments in QDSCs, including 1) the effect of quantum confinement on QDSCs, 2) the multiple exciton generation (MEG) of QDs, 3) fabrication methods of QDs, and 4) nanocrystalline photoelectrodes for solar cells. We also make suggestions for future research on QDSCs. Although the efficiency of QDSCs is still low, we think there will be major breakthroughs in developing QDSCs in the future. PMID:24191178

Tian, Jianjun; Cao, Guozhong

2013-01-01

416

Improved conversion efficiency of amorphous Si solar cells using a mesoporous ZnO pattern  

NASA Astrophysics Data System (ADS)

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.

Go, Bit-Na; Kim, Yang Doo; suk Oh, Kyoung; Kim, Chaehyun; Choi, Hak-Jong; Lee, Heon

2014-09-01

417

Improved conversion efficiency of amorphous Si solar cells using a mesoporous ZnO pattern  

PubMed Central

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

2014-01-01

418

Improved conversion efficiency of amorphous Si solar cells using a mesoporous ZnO pattern.  

PubMed

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

Go, Bit-Na; Kim, Yang Doo; Suk Oh, Kyoung; Kim, Chaehyun; Choi, Hak-Jong; Lee, Heon

2014-01-01

419

Minimizing interfacial losses in inverted organic solar cells comprising Al-doped ZnO  

NASA Astrophysics Data System (ADS)

We demonstrated a 35% enhancement in the efficiency of inverted solar cells as a result of increased open-circuit voltage and fill factor by adsorbing an ultrathin layer of a ruthenium dye N719 on an aluminum-doped zinc oxide (ZnO-Al) electron collecting interfacial layer. The interface modification with N719 changes the charge injection levels as indicated by ultraviolet photoemission spectroscopy. The efficiency of inverted solar cells comprising a bulk heterojunction photo-active film of poly(3-hexylthiophene) and phenyl-C61-butyric acid methyl ester has increased from 2.80% to 3.80% upon employing the dye modification of the electrode interface.

Gadisa, Abay; Liu, Yingchi; Samulski, Edward T.; Lopez, Rene

2012-06-01

420

Heat-sterilized silver oxide-zinc cells: Cycle life studies  

NASA Technical Reports Server (NTRS)

A JPL study was conducted to evaluate the cell design parameters that contribute to the cycle life of sealed, heat-sterilized silver oxide-zinc cells. Test cells having a rated capacity of 4.2 A-h were fabricated using zinc oxide electrodes prepared by the sintered Teflon process. Two separator variations were evaluated, one having acrylic acid and the other methacrylic acid grafted to irradiated polyethylene film. Significant results of this study include the following: (1) cycle life in excess of 300 cycles was attained; (2) a zinc oxide/silver stoichiometric ratio of 1.5 resulted in greater cycle life than a ratio of 1.1, and similar cycle life to cells having a ratio of 2; (3) cells having methacrylic acid grafted separators suffered somewhat less in capacity loss due to zinc electrode shape change than cells having acrylic acid type; (4) use of acrylic acid grafted separators was slightly superior to the methacrylic acid type in respect to silver penetration; and (5) the inclusion of a layer of potassium titanate paper adjacent to the zinc electrodes resulted in cells that achieved higher cycle life before any of the group failed than that reached by cells of any other construction.

Arms, J. T.

1973-01-01

421

The V-groove multijunction solar cell  

Microsoft Academic Search

A new type of silicon photovoltaic converter has been developed called the V-Groove Multijunction (VGMJ) solar cell. The VGMJ solar cell consists of an array of many individual diode elements connected in series to produce a high-voltage low-current output. All the elements of the cell are formed simultaneously from a single silicon wafer by V-groove etching. The results of detailed

TERRY I. CHAPPELL

1979-01-01

422

Improving Solar Cells With Polycrystalline Silicon  

NASA Technical Reports Server (NTRS)

In proposed solar-cell design, layers of polycrystalline silicon grown near front metal grid and back metal surface. Net electrical effect increases open-circuit voltage and short-circuit current, resulting in greater cell power output and energy conversion efficiency. Solar-cell configuration differs from existing one in that layers of doped polycrystalline silicon added to reduce recombination in emitter and back surface field regions.

Rohatgi, Ajeet; Campbell, Robert B.; Rai-Choudhury, Prosenjit

1987-01-01

423

LDEF solar cell radiation effects analysis  

NASA Technical Reports Server (NTRS)

Because of the extended time that the Long Duration Exposure Facility (LDEF) mission stayed in space, the solar cells on the satellite experienced greater environments than originally planned. The cells showed an overall degradation in performance that is due to the combined effects of the various space environments. The purpose of this analysis is to calculate the effect of the accumulated radiation on the solar cells, thereby helping Marshall Space Flight Center (MSFC) to unravel the relative power degradation from the different environments.

Rives, Carol J.; Azarewicz, Joseph L.; Massengill, Lloyd

1993-01-01

424

Enhancement of oxygen vacancies and solar photocatalytic activity of zinc oxide by incorporation of nonmetal  

NASA Astrophysics Data System (ADS)

B-doped ZnO and N-doped ZnO powders have been synthesized by mechanochemical method and characterized by TG-DTA, XRD, SEM-EDX, XPS, UV-visible and photoluminescence (PL) spectra. X-ray diffraction data suggests the hexagonal wurtzite structure for modified ZnO crystallites and the incorporation of nonmetal expands the lattice constants of ZnO. The room temperature PL spectra suggest more number of oxygen vacancies exist in nonmetal-doped ZnO than that of undoped zinc oxide. XPS analysis shows the substitution of some of the O atoms of ZnO by nonmetal atoms. Solar photocatalytic activity of B-doped ZnO, N-doped ZnO and undoped ZnO was compared by means of oxidative photocatalytic degradation (PCD) of Bisphenol A (BPA). B-doped ZnO showed better solar PCD efficiency as compare to N-doped ZnO and undoped ZnO. The PCD of BPA follows first order reaction kinetics. The detail mechanism of PCD of Bisphenol A was proposed with the identification of intermediates such as hydroquinone, benzene-1,2,4-triol and 4-(2-hydroxypropan-2-yl) phenol.

Patil, Ashokrao B.; Patil, Kashinath R.; Pardeshi, Satish K.

2011-12-01

425

Zinc regulates iNOS-derived nitric oxide formation in endothelial cells  

PubMed Central

Aberrant production of nitric oxide (NO) by inducible NO synthase (iNOS) has been implicated in the pathogenesis of endothelial dysfunction and vascular disease. Mechanisms responsible for the fine-tuning of iNOS activity in inflammation are still not fully understood. Zinc is an important structural element of NOS enzymes and is known to inhibit its catalytical activity. In this study we aimed to investigate the effects of zinc on iNOS activity and expression in endothelial cells. We found that zinc down-regulated the expression of iNOS (mRNA+protein) and decreased cytokine-mediated activation of the iNOS promoter. Zinc-mediated regulation of iNOS expression was due to inhibition of NF-?B transactivation activity, as determined by a decrease in both NF-?B-driven luciferase reporter activity and expression of NF-?B target genes, including cyclooxygenase 2 and IL-1?. However, zinc did not affect NF-?B translocation into the nucleus, as assessed by Western blot analysis of nuclear and cytoplasmic fractions. Taken together our results demonstrate that zinc limits iNOS-derived high output NO production in endothelial cells by inhibiting NF-?B-dependent iNOS expression, pointing to a role of zinc as a regulator of iNOS activity in inflammation. PMID:25180171

Cortese-Krott, Miriam M.; Kulakov, Larissa; Oplnder, Christian; Kolb-Bachofen, Victoria; Krncke, Klaus-D.; Suschek, Christoph V.

2014-01-01

426

Characterising dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

With growing energy and environmental concerns due to fossil fuel depletion and global warming there is an increasing attention being attracted by alternative and/or renewable sources of power such as biomass, hydropower, geothermal, wind and solar energy. In today's society there is a vast and in many cases not fully appreciated dependence on electrical power for everyday life and therefore devices such as PV cells are of enormous importance. The more widely used and commercially available silicon (semiconductor) based cells currently have the greatest efficiencies, however the manufacturing of these cells is complex and costly due to the cost and difficulty of producing and processing pure silicon. One new direction being explored is the development of dye-sensitised solar cells (DSSC). The SFI Strategic Research Centre for Solar Energy Conversion is a new research cluster based in Ireland, formed with the express intention of bringing together industry and academia to produce renewable energy solutions. Our specific area of research is in biomimetic dye sensitised solar cells and their electrical properties. We are currently working to develop test equipment, and optoelectronic models describing the performance and behaviors of dye-sensitised solar cells (Grtzel Cells). In this paper we describe some of the background to our work and also some of our initial experimental results. Based on these results we intend to characterise the opto-electrical properties and bulk characteristics of simple dye-sensitised solar cells and then to proceed to test new cell compositions.

Tobin, Laura L.; O'Reilly, Thomas; Zerulla, Dominic; Sheridan, John T.

2009-08-01

427

Zinc Restored the Decreased Vascular Smooth Muscle Cell Viability under Atherosclerotic Calcification Conditions  

PubMed Central

Zinc is considered to be involved in maintaining healthy vascular condition. Atherosclerotic calcification of vascular smooth muscle cells (VSMCs) occurs via the mechanism of cell death; therefore, cell viability is a critical factor for preventing VSMC calcification. In this study, we tested whether zinc affected VSMC viability under both normal physiological non-calcifying (0 mM P) and atherosclerotic calcifying conditions (3 and 5 mM P), since VSMC physiological characters change during the VSMC calcification process. The study results showed that an optimal zinc level (15 ?M) restored the decreased VSMC viability which was induced under low zinc levels (0 and 1 ?M) and calcifying conditions (3 and 5 mM P) at 9 and 15 days culture. This zinc-protecting effect for VSMC viability is more prominent under atherosclerotic calcifying condition (3 and 5 mM P) than normal condition (0 mM P). Also, the increased VSMC viability was consistent with the decreased Ca and P accumulation in VSMC cell layers. The results suggested that zinc could be an effective biomineral for preventing VSMC calcification under atherosclerotic calcifying conditions. PMID:25580404

Shin, Mee-Young; Kwun, In-Sook

2014-01-01

428

Enhanced Gadd45 expression and delayed G2/M progression are p53 dependent in zinc-supplemented human bronchial epithelial cells  

Technology Transfer Automated Retrieval System (TEKTRAN)

Zinc is an essential nutrient for humans; however, this study demonstrated for the first time that an elevated zinc status, created by culturing cells at optimal plasma zinc concentration attainable by oral zinc supplementation, is cytotoxic for normal human bronchial epithelial (NHBE) cells. p53 p...

429

Heterojunction solar cell with passivated emitter surface  

DOEpatents

A high-efficiency heterojunction solar cell wherein a thin emitter layer (preferably Ga.sub.0.52 In.sub.0.48 P) forms a heterojunction with a GaAs absorber layer. A passivating window layer of defined composition is disposed over the emitter layer. The conversion efficiency of the solar cell is at least 25.7%. The solar cell preferably includes a passivating layer between the substrate and the absorber layer. An anti-reflection coating is preferably disposed over the window layer.

Olson, Jerry M. (Lakewood, CO); Kurtz, Sarah R. (Golden, CO)

1994-01-01

430

Bypass diode for a solar cell  

DOEpatents

Methods of fabricating bypass diodes for solar cells are described. In once embodiment, a method includes forming a first conductive region of a first conductivity type above a substrate of a solar cell. A second conductive region of a second conductivity type is formed on the first conductive region. In another embodiment, a method includes forming a first conductive region of a first conductivity type above a substrate of a solar cell. A second conductive region of a second conductivity type is formed within, and surrounded by, an uppermost portion of the first conductive region but is not formed in a lowermost portion of the first conductive region.

Rim, Seung Bum; Kim, Taeseok; Smith, David D; Cousins, Peter J

2013-11-12

431

Heterojunction solar cell with passivated emitter surface  

DOEpatents

A high-efficiency heterojunction solar cell is described wherein a thin emitter layer (preferably Ga[sub 0.52]In[sub 0.48]P) forms a heterojunction with a GaAs absorber layer. A passivating window layer of defined composition is disposed over the emitter layer. The conversion efficiency of the solar cell is at least 25.7%. The solar cell preferably includes a passivating layer between the substrate and the absorber layer. An anti-reflection coating is preferably disposed over the window layer. 1 fig.

Olson, J.M.; Kurtz, S.R.

1994-05-31

432

Temperature coefficients of multijunction solar cells  

NASA Technical Reports Server (NTRS)

Temperature coefficients measured in solar simulators with those measured under AM0 solar illumination are compared to illustrate the challenges in making these measurements. It is shown that simulator measurements of the short-circuit current (delta Jsc/delta T) are inaccurate due to the mismatch between the solar spectrum and the simulators at the bandgaps of the solar cells. Especially susceptible to error is the delta Jsc/delta T of cells which are components in monolithic multijunction solar cells, such as GaAs filtered by 1.93-eV AlGaAs, which has an AM0 coefficient of 6.82 micro-A/sq cm/deg C, compared to a Xenon simulator coefficient of 22.2 micro-A/sq cm/deg C.

Virshup, G. F.; Chung, B.-C.; Ladle Ristow, M.; Kuryla, M. S.; Brinker, D.

1990-01-01

433

Solar cell anomaly detection method and apparatus  

NASA Technical Reports Server (NTRS)

A method is provided for detecting cracks and other imperfections in a solar cell, which includes scanning a narrow light beam back and forth across the cell in a raster pattern, while monitoring the electrical output of the cell to find locations where the electrical output varies significantly. The electrical output can be monitored on a television type screen containing a raster pattern with each point on the screen corresponding to a point on the solar cell surface, and with the brightness of each point on the screen corresponding to the electrical output from the cell which was produced when the light beam was at the corresponding point on the cell. The technique can be utilized to scan a large array of interconnected solar cells, to determine which ones are defective.

Miller, Emmett L. (Inventor); Shumka, Alex (Inventor); Gauthier, Michael K. (Inventor)

1981-01-01

434

Final Report: Sintered CZTS Nanoparticle Solar Cells on Metal Foil; July 26, 2011 - July 25, 2012  

SciTech Connect

This is the final report covering 12 months of this subcontract for research on high-efficiency copper zinc tin sulfide (CZTS)-based thin-film solar cells on flexible metal foil. Each of the first three quarters of the subcontract has been detailed in quarterly reports. In this final report highlights of the first three quarters will be provided and details will be given of the final quarter of the subcontract.

Leidholm, C.; Hotz, C.; Breeze, A.; Sunderland, C.; Ki, W.; Zehnder, D.

2012-09-01

435

Amine-based polar solvent treatment for highly efficient inverted polymer solar cells.  

PubMed

The interfacial dipolar polarization in inverted structure polymer solar cells, which arises spontaneously from the absorption of ethanolamine end groups, such as amine and hydroxyl groups on ripple-structure zinc oxide (ZnO-R), lowers the contact barrier for electron transport and extraction and leads to enhanced electron mobility, suppression of bimolecular recombination, reduction of the contact resistance and series resistance, and remarkable enhancement of the power conversion efficiency. PMID:24114852

Lee, Bo Ram; Jung, Eui Dae; Nam, Yun Seok; Jung, Minbok; Park, Ji Sun; Lee, Seungjin; Choi, Hyosung; Ko, Seo-Jin; Shin, Na Ra; Kim, Young-Kuk; Kim, Sang Ouk; Kim, Jin Young; Shin, Hyung-Joon; Cho, Shinuk; Song, Myoung Hoon

2014-01-22

436

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

DOEpatents

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

Bhattacharya, Raghu N. (Littleton, CO)

2009-11-03

437

Zinc ionophore activity of quercetin and epigallocatechin-gallate: from Hepa 1-6 cells to a liposome model.  

PubMed

Labile zinc, a tiny fraction of total intracellular zinc that is loosely bound to proteins and easily interchangeable, modulates the activity of numerous signaling and metabolic pathways. Dietary plant polyphenols such as the flavonoids quercetin (QCT) and epigallocatechin-gallate act as antioxidants and as signaling molecules. Remarkably, the activities of numerous enzymes that are targeted by polyphenols are dependent on zinc. We have previously shown that these polyphenols chelate zinc cations and hypothesized that these flavonoids might be also acting as zinc ionophores, transporting zinc cations through the plasma membrane. To prove this hypothesis, herein, we have demonstrated the capacity of QCT and epigallocatechin-gallate to rapidly increase labile zinc in mouse hepatocarcinoma Hepa 1-6 cells as well as, for the first time, in liposomes. In order to confirm that the polyphenols transport zinc cations across the plasma membrane independently of plasma membrane zinc transporters, QCT, epigallocatechin-gallate, or clioquinol (CQ), alone and combined with zinc, were added to unilamellar dipalmitoylphosphocholine/cholesterol liposomes loaded with membrane-impermeant FluoZin-3. Only the combinations of the chelators with zinc triggered a rapid increase of FluoZin-3 fluorescence within the liposomes, thus demonstrating the ionophore action of QCT, epigallocatechin-gallate, and CQ on lipid membrane systems. The ionophore activity of dietary polyphenols may underlay the raising of labile zinc levels triggered in cells by polyphenols and thus many of their biological actions. PMID:25050823

Dabbagh-Bazarbachi, Husam; Clergeaud, Gael; Quesada, Isabel M; Ortiz, Mayreli; O'Sullivan, Ciara K; Fernndez-Larrea, Juan B

2014-08-13

438

Zinc uptake by proximal cells isolated from rabbit kidney: effects of cysteine and histidine.  

PubMed

The aim of this study was to characterize the mechanisms of zinc transport in proximal cells isolated from rabbit kidney cortex. Uptakes of 65Zn were assessed under initial rate conditions, after 0.5 min of incubation. The kinetic parameters obtained at 20 degrees C were a Km of 15.0 +/- 1.5 microM, a Jmax of 208.0 +/- 8.4 pmol min-1 (mg protein)-1, and an unsaturable constant of 0.259 +/- 0.104 (n = 8). Cadmium competitively inhibited the zinc uptake, with a Ki value of 13.0 +/- 2.8 microM, while zinc competitively inhibited 109Cd uptake by isolated cells. Cysteine and histidine stimulated zinc transport at an amino acid:zinc molar ratio ranging from 1:1 to 8:1. This stimulation was not observed in the absence of a sodium gradient. At a molar ratio greater than 16:1 (i.e. 400 microM cysteine or histidine and 25 microM Zn), there was evidence of inhibition. These data suggest that zinc enters renal proximal cells (a) as a free ion via a saturable carrier-mediated process or an unsaturable pathway and (b) complexed with cysteine or histidine, by means of a sodium/amino acid cotransport mechanism. PMID:1788054

Gachot, B; Tauc, M; Morat, L; Poujeol, P

1991-12-01

439

Disulfiram-induced cytotoxicity and endo-lysosomal sequestration of zinc in breast cancer cells  

PubMed Central

Disulfiram, a clinically used alcohol-deterrent has gained prominence as a potential anti-cancer agent due to its impact on copper-dependent processes. Few studies have investigated zinc effects on disulfiram action, despite it having high affinity for this metal. Here we studied the cytotoxic effects of disulfiram in breast cancer cells, and its relationship with both intra and extracellular zinc. MCF-7 and BT474 cancer cell lines gave a striking time-dependent biphasic cytotoxic response between 0.01 and 10?M disulfiram. Co-incubation of disulfiram with low-level zinc removed this effect, suggesting that availability of extracellular zinc significantly influences disulfiram efficacy. Live-cell confocal microscopy using fluorescent endocytic probes and the zinc dye Fluozin-3 revealed that disulfiram selectively and rapidly increased zinc levels in endo-lysosomes. Disulfiram also caused spatial disorganization of late endosomes and lysosomes, suggesting they are novel targets for this drug. This relationship between disulfiram toxicity and ionophore activity was consolidated via synthesis of a new disulfiram analog and overall we demonstrate a novel mechanism of disulfiram-cytotoxicity with significant clinical implications for future use as a cancer therapeutic. PMID:25557293

Wiggins, Helen L.; Wymant, Jennifer M.; Solfa, Francesca; Hiscox, Stephen E.; Taylor, Kathryn M.; Westwell, Andrew D.; Jones, Arwyn T.

2015-01-01

440

Germanium-on-glass solar cells  

Microsoft Academic Search

We report on the fabrication and characterization of Ge solar cells on glass realized by layer transfer and epitaxial regrowth. These devices exhibit typical conversion efficiency exceeding 2.4% under AM1.5 irradiation and maximum efficiency of 3.7% under concentrated excitation. This approach enables flexible and affordable multi-junction engineering for solar energy conversion.

Lorenzo Colace; Vito Sorianello; Carlo Maragliano; Gaetano Assanto; D. Fulgoni; L. Nash; M. Palmer

2011-01-01

441

Radiation degradation of solar cell arrays  

NASA Technical Reports Server (NTRS)

A method of incorporating a detailed solar cell radiation degradation model into a convenient computational scheme suitable for the solar electric propulsion system is outlined. The study shows that several existing codes may be applied in sequence to solve the problem.

Hill, C. W.

1975-01-01

442

A zinc-resistant human epithelial cell line is impaired in cadmium and manganese import  

SciTech Connect

A human epithelial cell line (HZR) growing with high zinc concentrations has been analyzed for its ability to sustain high cadmium concentrations. Exposure to up to 200 {mu}M of cadmium acetate for 24 h hardly impacted viability, whereas most