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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

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

4

Zinc phosphide poisoning.  

PubMed

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; Cifti, Taner; Aycan, Ilker; Celik, Feyzi; Cetin, Bedri; Kavak, Gnl lmez

2014-01-01

5

Radiation damage in proton irradiated indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

Indium phosphide solar cells exposed to 10 MeV proton irradiations were found to have significantly greater radiation resistance than either GaAs or Si. Performance predictions were obtained for two proton dominated orbits and one in which both protons and electrons were significant cell degradation factors. Array specific power was calculated using lightweight blanket technology, a SEP array structure, and projected cell efficiencies. Results indicate that arrays using fully developed InP cells should out-perform those using GaAs or Si in orbits where radiation is a significant cell degradation factor.

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

1986-01-01

6

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

7

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

8

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

9

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

10

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

11

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

12

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

13

Rational Design of Zinc Phosphide Heterojunction Photovoltaics  

NASA Astrophysics Data System (ADS)

The prospect of terawatt-scale electricity generation using a photovoltaic (PV) device places strict requirements on the active semiconductor optoelectronic properties and elemental abundance. After reviewing the constraints placed on an ``earth-abundant'' solar absorber, we find zinc phosphide (?-Zn 3P2) to be an ideal candidate. In addition to its near-optimal direct band gap of 1.5 eV, high visible-light absorption coefficient (>10. 4cm-1), and long minority-carrier diffusion length (>5 ?m), Zn3P 2 is composed of abundant Zn and P elements and has excellent physical properties for scalable thin-film deposition. However, to date, a Zn 3P2 device of sufficient efficiency for commercial applications has not been demonstrated. Record efficiencies of 6.0% for multicrystalline and 4.3% for thin-film cells have been reported, respectively. Performance has been limited by the intrinsic p-type conductivity of Zn3P 2 which restricts us to Schottky and heterojunction device designs. Due to our poor understanding of Zn3P2 interfaces, an ideal heterojunction partner has not yet been found. The goal of this thesis is to explore the upper limit of solar conversion efficiency achievable with a Zn3P2 absorber through the design of an optimal heterojunction PV device. To do so, we investigate three key aspects of material growth, interface energetics, and device design. First, the growth of Zn3P2 on GaAs(001) is studied using compound-source molecular-beam epitaxy (MBE). We successfully demonstrate the pseudomorphic growth of Zn3P2 epilayers of controlled orientation and optoelectronic properties. Next, the energy-band alignments of epitaxial Zn3P2 and II-VI and III-V semiconductor interfaces are measured via high-resolution x-ray photoelectron spectroscopy in order to determine the most appropriate heterojunction partner. From this work, we identify ZnSe as a nearly ideal n-type emitter for a Zn3P 2 PV device. Finally, various II-VI/Zn3P2 heterojunction solar cells designs are fabricated, including substrate and superstrate architectures, and evaluated based on their solar conversion efficiency.

Bosco, Jeffrey Paul

14

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

15

Potential for use of indium phosphide solar cells in the space radiation environment  

NASA Technical Reports Server (NTRS)

Indium phosphide solar cells were observed to have significantly higher radiation resistance than either GaAs or Si after exposure to 10 MeV proton irradiation data and previous 1 MeV electron data together with projected efficiencies for InP, it was found that these latter cells produced more output power than either GaAs or Si after specified fluences of 10 MeV protons and 1 MeV electrons. Estimates of expected performance in a proton dominated space orbit yielded much less degradation for InP when compared to the remaining two cell types. It was concluded that, with additional development to increase efficiency, InP solar cells would perform significantly better than either GaAs or Si in the space radiation environment.

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

1985-01-01

16

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

17

Laboratory diagnosis of zinc phosphide poisoning.  

PubMed

Zinc phosphide, a readily-available rodenticide, poses a significant risk for intoxication in animals. Animals have been poisoned by ingesting treated bait or the carcasses of poisoned rodents. Toxicity is due to the liberation of phosphine gas in the stomach. Clinical signs include central nervous system excitation, depression and vomition. Similarities of clinical signs with other central nervous system toxicants make the diagnosis difficult without a specific diagnostic test. The procedure outlined in this paper detects phosphine liberated from zinc phosphide by the addition of hydrochloric acid as well as the phosphine previously generated by contact with stomach acid. PMID:7900268

Guale, F G; Stair, E L; Johnson, B W; Edwards, W C; Haliburton, J C

1994-12-01

18

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

19

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

20

Diffusion length variation in 0. 5- and 3-MeV-proton-irradiated, heteroepitaxial indium phosphide solar cells  

SciTech Connect

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

1993-04-01

21

40 CFR 180.284 - Zinc phosphide; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

...for residues of the phosphine resulting from the use of the rodenticide zinc phosphide in or on the raw agricultural commodities...established for residues of phosphine resulting from the use of the rodenticide zinc phosphide in or on the following raw agricultural...

2013-07-01

22

40 CFR 180.284 - Zinc phosphide; tolerances for residues.  

...for residues of the phosphine resulting from the use of the rodenticide zinc phosphide in or on the raw agricultural commodities...established for residues of phosphine resulting from the use of the rodenticide zinc phosphide in or on the following raw agricultural...

2014-07-01

23

40 CFR 180.284 - Zinc phosphide; tolerances for residues.  

Code of Federal Regulations, 2012 CFR

...for residues of the phosphine resulting from the use of the rodenticide zinc phosphide in or on the raw agricultural commodities...established for residues of phosphine resulting from the use of the rodenticide zinc phosphide in or on the following raw agricultural...

2012-07-01

24

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

SciTech Connect

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 POCl{sub 3} 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 V{sub oc}. 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 [Department of Solar Energy, Institute Solid-State Physics, Leibniz University of Hannover, Appelstr. 2, 30167 Hannover (Germany); ARC Photovoltaics Centre of Excellence, University of New South Wales (UNSW), Sydney, NSW 2052 (Australia); Ohrdes, Tobias [Institute for Solar Energy Research Hamelin (ISFH), 31860 Emmerthal (Germany); Dastgheib-Shirazi, Amir [Div. Photovoltaics, Department of Physics, University of Konstanz, 78457 Konstanz (Germany); Puthen-Veettil, Binesh; Knig, Dirk [ARC Photovoltaics Centre of Excellence, University of New South Wales (UNSW), Sydney, NSW 2052 (Australia); Altermatt, Pietro P. [Department of Solar Energy, Institute Solid-State Physics, Leibniz University of Hannover, Appelstr. 2, 30167 Hannover (Germany)

2014-01-28

25

High-efficiency indium tin oxide/indium phosphide solar cells  

SciTech Connect

Improvements in the performance of indium tin oxide/indium phosphide (ITO/InP) solar cells have been achieved by using dc magnetron sputter deposited /ital n/-ITO onto an epitaxial /ital p///ital p//sup +/ structure grown on good quality commercial /ital p//sup +/ bulk substrates. The composition of the sputtering gas has been investigated and the highest efficiency cells resulted when the surface of the epilayer was exposed to an Ar/H/sub 2/ plasma before depositing the bulk of the ITO in a more typical Ar/O/sub 2/ plasma. With H/sub 2/ processing, record efficiencies of 18.9% global, 1000 W m/sup /minus/2/, 25 /degree/C (17.0% air mass zero) were achieved. Without H/sub 2/ processing, the devices exhibited lower efficiencies and were unstable. Type conversion of the InP was shown to occur and was established as being associated with the ITO (possibly due to Sn donors) rather than sputter damage. These improvements in performance have resulted from the optimization of the doping, thickness, transport, and surface properties of the /ital 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.

1989-06-26

26

Epitaxial gallium phosphide on silicon (111) from the liquid phase for solar cell applications  

NASA Astrophysics Data System (ADS)

Multijunction structures composed of III-V materials grown on a III-V or Ge substrate are often employed to achieve high solar cell conversion efficiencies. However, it is advantageous to consider alternate substrates that can lower cost, such as the well developed Si, as a platform on which multi-junction solar structures can be grown. Growth of III-Vs on an alternate substrate such as Si requires careful consideration of the lattice constant mismatch as this will greatly influence the physical and electronic quality of the film. A material that is closely lattice matched with Si is Gallium phosphide (GaP). This lattice matching allows for good quality epitaxial growth and GaP can be alloyed with other III-V materials to tune the bandgap, which is an important property for multi-junction solar cells. In this work, liquid phase epitaxy (LPE) was used to grow GaP films on miscut and aligned Si (111) substrates. The films have been characterized by SEM and XRD to show that the GaP films are planar with uniform morphology and good crystal quality. The composition has been found by XPS and Auger spectroscopy to be GaP with 10-20% Si content. High resolution XRD analysis confirmed that the films are epitaxial and have a threading dislocation density of 2 x 106 cm-2 for growth on aligned Si (111) which is promising for the development of III-V/Si multi-junction solar cells. A four junction solar cell stack that includes a Si junction has a theoretical efficiency greater than 50%. In this structure, a GaP layer can act as a buffer layer on Si to growth other III-V materials with optimized bandgaps. Therefore, the effect of a GaP film on a Si solar cell was investigated. The results of this investigation show that growing a GaP layer on a Si solar cell fabricated by a diffusion process increases the series resistance and has lower Voc. Quantum efficiency measurements show that there is some reduction in efficiency of collection of carriers excited by wavelengths shorter than 450 nm which could be due to absorption in the GaP layer and recombination at the interface. A GaP layer grown on a p-type Si substrate exhibited similar current voltage characteristics as the GaP layer grown on a Si solar cell. SIMS depth profiling showed that phosphorus diffusion occurs during growth of GaP, creating a n-type doped. This indicates that a GaP layer can be grown on a Si substrate to directly make a solar cell. Epitaxial GaP layers have been grown on Si (111) substrates with high crystal quality which is promising for use as a buffer layer. Growth of GaP on Si can be used to directly fabricate a Si solar cell. This GaP/Si structure will be beneficial to solar cell and many other optoelectronic applications.

Huang, Susan R.

27

40 CFR 180.284 - Zinc phosphide; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...false Zinc phosphide; tolerances for residues. 180.284 Section 180.284...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances ...

2010-07-01

28

Zinc phosphide ingestion: a case report and review.  

PubMed

We present the case of a patient who attempted suicide by ingestion of the rodenticide zinc phosphide. Zinc phosphide manifests its immediate toxicity through production of phosphine gas. Signs and symptoms of toxicity include nausea, vomiting, dyspnea, and changes in mental status; immediate death results from pulmonary edema. Delayed effects are secondary to the absorption of phosphide, affecting primarily the liver, heart and kidneys. Delayed deaths are related to a direct cardiotoxicity. Treatment is mainly symptomatic and supportive; aggressive airway management and circulatory support are critical to a successful outcome. PMID:2575817

Rodenberg, H D; Chang, C C; Watson, W A

1989-12-01

29

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

30

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

31

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

32

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

33

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

34

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

35

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

Microsoft Academic Search

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

Geoffrey P. Summers

1995-01-01

36

Effect of zinc impurity on silicon solar-cell efficiency  

NASA Technical Reports Server (NTRS)

Zinc is a major residue impurity in the preparation of solar-grade silicon material by the zinc vapor reduction of silicon tetrachloride. This paper projects that in order to get a 17-percent AM1 cell efficiency for the Block IV module of the Low-Cost Solar Array Project, the concentration of the zinc recombination centers in the base region of silicon solar cells must be less than 4 x 10 to the 11th Zn/cu cm in the p-base n+/p/p+ cell and 7 x 10 to the 11th Zn/cu cm in the n-base p+/n/n+ cell for a base dopant impurity concentration of 5 x 10 to the 14 atoms/cu cm. If the base dopant impurity concentration is increased by a factor of 10 to 5 x 10 to the 15th atoms/cu cm, then the maximum allowable zinc concentration is increased by a factor of about two for a 17-percent AM1 efficiency. The thermal equilibrium electron and hole recombination and generation rates at the double-acceptor zinc centers are obtained from previous high-field measurements as well as new measurements at zero field described in this paper. These rates are used in the exact dc-circuit model to compute the projections.

Sah, C.-T.; Chan, P. C. H.; Wang, C.-K.; Yamakawa, K. A.; Lutwack, R.; Sah, R. L.-Y.

1981-01-01

37

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

38

Indium tin oxide and indium phosphide heterojunction nanowire array solar cells  

NASA Astrophysics Data System (ADS)

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/cm2, 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; Nakai, Eiji; Tomioka, Katsuhiro; Fukui, Takashi

2013-12-01

39

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

40

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

41

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

NASA Technical Reports Server (NTRS)

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 AM0, 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. Over the last few years, NRL and Steve Wojtczuk at Spire have been developing a single junction InP on Si cell, in an ONR-sponsored SBIR program. Both cell polarities were investigated and the best efficiencies to date (approximately 13% on a 2 x 4 sq cm cell) were achieved with n/p cells. Earlier this year NRL began a program with ASEC to develop a two terminal InP-InGaAs tandem cell on a Ge substrate. RTI and NREL are subcontractors on this program. The results of an ONR-sponsored study of the potential market for InP/Si cells will be discussed. Also the technical status of both the InP/Si and the InP-InGaAs/Ge programs will be given. The technical challenges still remaining will be briefly described.

Summers, Geoffrey P.

1995-01-01

42

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

NASA Astrophysics Data System (ADS)

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 AM0, 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. Over the last few years, NRL and Steve Wojtczuk at Spire have been developing a single junction InP on Si cell, in an ONR-sponsored SBIR program. Both cell polarities were investigated and the best efficiencies to date (approximately 13% on a 2 x 4 sq cm cell) were achieved with n/p cells. Earlier this year NRL began a program with ASEC to develop a two terminal InP-InGaAs tandem cell on a Ge substrate. RTI and NREL are subcontractors on this program. The results of an ONR-sponsored study of the potential market for InP/Si cells will be discussed.

Summers, Geoffrey P.

1995-10-01

43

1-Dimensional Zinc Oxide Nanomaterial Growth and Solar Cell Applications  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) has attracted much interest during last decades as a functional material. Furthermore, ZnO is a potential material for transparent conducting oxide material competing with indium tin oxide (ITO), graphene, and carbon nanotube film. It has been known as a conductive material when doped with elements such as indium, gallium and aluminum. The solubility of those dopant elements in ZnO is still debatable; but, it is necessary to find alternative conducting materials when their form is film or nanostructure for display devices. This is a consequence of the ever increasing price of indium. In addition, a new generation solar cell (nanostructured or hybrid photovoltaics) requires compatible materials which are capable of free standing on substrates without seed or buffer layers and have the ability introduce electrons or holes pathway without blocking towards electrodes. The nanostructures for solar cells using inorganic materials such as silicon (Si), titanium oxide (TiO2), and ZnO have been an interesting topic for research in solar cell community in order to overcome the limitation of efficiency for organic solar cells. This dissertation is a study of the rational solution-based synthesis of 1-dimentional ZnO nanomaterial and its solar cell applications. These results have implications in cost effective and uniform nanomanufacturing for the next generation solar cells application by controlling growth condition and by doping transition metal element in solution.

Choi, Hyung Woo

44

Zinc phosphide intoxication symptoms: analysis of 20 cases.  

PubMed

Twenty cases of zinc phosphide (Zn3P2) ingestion (self-poisoning) were seen during the last 5 years (January 1992-December 1996). Poisoning was rare before 1986. Profuse vomiting (100%), pain in abdomen (100%), palpitation and sweating (80%), dyspnea and tachypnea (75%), metabolic acidosis (60%), shock (40%), and hypotension (40%) were the most common presenting features. Five patients (25%) died. The toxic effects were due to liberation of toxic phosphine (PH3) gas which was detected by qualitative silver nitrate paper test in majority of cases. PMID:9707358

Chugh, S N; Aggarwal, H K; Mahajan, S K

1998-07-01

45

Radiation and temperature effects in gallium arsenide, indium phosphide and silicon solar cells  

NASA Technical Reports Server (NTRS)

The effects of radiation on performance are determined for both n(+)p and p(+)n GaAs and InP cells and for silicon n(+)p cells. It is found that the radiation resistance of InP is greater than that of both GaAs and Si under 1 MeV electron irradiation. For silicon, the observed decreased radiation resistance with decreased resistivity is attributed to the presence of a radiation induced boron-oxygen defect. Comparison of radiation damage in both p(+)n and n(+)p GaAs cells yields a decreased radiation resistance for the n(+)p cell attributable to increased series resistance, decreased shunt resistance, and relatively greater losses in the cell's p-region. For InP, the n(+)p configuration is found to have greater radiation resistance than the p(+)n cell. The increased loss in this latter cell is attributed to losses in the cell's emitter region. Temperature dependency results are interpreted using a theoretical relation for dVoc/cT which predicts that increased Voc should results in decreased numerical values for dPm/dT. The predicted correlation is observed for GaAs but not for InP a result which is attributed to variations in cell processing.

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

1987-01-01

46

Radiation and temperature effects in gallium arsenide, indium phosphide, and silicon solar cells  

NASA Technical Reports Server (NTRS)

The effects of radiation on performance are determined for both n+p and p+n GaAs and InP cells and for silicon n+p cells. It is found that the radiation resistance of InP is greater than that of both GaAs and Si under 1-MeV electron irradiation. For silicon, the observed decreased radiation resistance with decreased resistivity is attributed to the presence of a radiation-induced boron-oxygen defect. Comparison of radiation damage in both p+n and n+p GaAs cells yields a decreased radiation resistance for the n+p cell attributable to increased series resistance, decreased shunt resistance, and relatively greater losses in the cell's p-region. For InP, the n+p configuration is found to have greater radiation resistance than the p+n cell. The increased loss in this latter cell is attributed to losses in the cell's emitter region. Temperature dependency results are interpreted using a theoretical relation for dVoc/dT, which predicts that increased Voc should result in decreased numerical values for dPm/dT. The predicted correlation is observed for GaAs but not for InP, a result which is attributed to variations in cell processing.

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

1987-01-01

47

Radiation and temperature effects in gallium aresenide, indium phosphide and silicon solar cells  

SciTech Connect

The effects of radiation on performance are determined for both n(+)p and p(+)n GaAs and InP cells and for silicon n(+)p cells. It is found that the radiation resistance of InP is greater than that of both GaAs and Si under 1 MeV electron irradiation. For silicon, the observed decreased radiation resistance with decreased resistivity is attributed to the presence of a radiation induced boron-oxygen defect. Comparison of radiation damage in both p(+)n and n(+)p GaAs cells yields a decreased radiation resistance for the n(+)p cell attributable to increased series resistance, decreased shunt resistance, and relatively greater losses in the cell's p-region. For InP, the n(+)p configuration is found to have greater radiation resistance than the p(+)n cell. The increased loss in this latter cell is attributed to losses in the cell's emitter region. Temperature dependency results are interpreted using a theoretical relation for dVoc/cT which predicts that increased Voc should results in decreased numerical values for dPm/dT. The predicted correlation is observed for GaAs but not for InP a result which is attributed to variations in cell processing.

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

1987-01-01

48

Effect of Zinc Phosphide Rodenticide on Prairie Dog Colony Expansion as Determined From Aerial Photography  

Microsoft Academic Search

Aerial photography (1:16,000) was used to evaluate the effectiveness of zinc phosphide in reducing area expansion of black-tailed prairie dog (Cynomys ludovicianus) colonies over a 5-year period in western South Dakota. Untreated prairie dog colonies increased 65 % in area, compared to a 1% increase on treated colonies (P = 0.11). Zinc phosphide, applied at 3-year intervals, was effective in

DANIEL W. URESK; GREG L. SCHENBECK

49

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

50

Photoelectronic properties of zinc phosphide crystals, films, and heterojunctions  

NASA Astrophysics Data System (ADS)

The research on zinc phosphides is summarized and includes: ZnP2 materials preparation; electrical characterization of Zn3P2 crystals; characterization by low temperature photoluminescence, photoconductivity, Auger electron spectroscopy, and transmission electron microscopy; investigation of Zn3P2 based devices; and Zn3P2 films grown by close spaced vapor transport. An approach to future research on Zn3P2 is summarized and includes: chemical vapor transport growth with ZnCl2, ZnBr2, and ZnI2; an investigation of defect structure vs deviations from stoichiometry; growth and properties of (Zn3P2)/sub x/Cd3P2)/sub 1-x/ solid solutions; surface investigation on Zn3P2; investigation on Zn3P2; reactive metal junctions; and MIS structures on Zn3P2. Appended are two manuscripts, one on transport mechanisms for mg/Zn3P2 junctions and the other on properties of Zn3P2 crystals and devices.

Bube, R. H.

51

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

52

Selecting bait base to increase uptake of zinc phosphide and warfarin rodenticide baits  

Microsoft Academic Search

Rodent pests cause major economic losses to rice crops and inflict health risk to people and live-stock in villages. Maize-based baits were used traditionally to control ricefield rodents. This study aimed to determine if replacing maize with rice as bait base would increase uptake of zinc phosphide and warfarin wax block baits in maturing rice crops, fallow fields and villages.

Luke K.-P. Leung; Sopheap Seth; Carly R. Starr; Sotheary El; Iean W. Russell; Christine A. King; Tea Rithy Vong; Phaloeun Chan

2007-01-01

53

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

54

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

55

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

56

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

57

Simulation assisted design of a gallium phosphide np photovoltaic junction Charles R. Allen, Jong-Hyeok Jeon , Jerry M. Woodall  

E-print Network

Simulation assisted design of a gallium phosphide n­p photovoltaic junction Charles R. Allen, Jong February 2010 Keywords: Gallium phosphide Solar cell Multi-junction CPV Simulation a b s t r a c t A gallium phosphide photovoltaic junction is reported. Using a n­p structure, a gallium phosphide junction

Woodall, Jerry M.

58

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

Microsoft Academic Search

The first year was covered of a program to investigate: (1) the deposition of CdTe films by various techniques; (2) the deposition of transparent conducting semiconductor (TCS) films by various techniques; (3) the preparation and evaluation of thin film CdTe solar cells; and (4) the deposition and characterization of ZnTe films and heterojunctions. CdTe films were deposited on glass and

T. L. Chu

1989-01-01

59

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

E-print Network

solar cells. In this letter, we present a SnS device with a record power conversion efficiency of 2Enhancing the efficiency of SnS solar cells via band-offset engineering with a zinc oxysulfide as an NREL-certified total-area power-conversion efficiency of 2.04% and an uncertified active

60

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

NASA Astrophysics Data System (ADS)

The first year was covered of a program to investigate: (1) the deposition of CdTe films by various techniques; (2) the deposition of transparent conducting semiconductor (TCS) films by various techniques; (3) the preparation and evaluation of thin film CdTe solar cells; and (4) the deposition and characterization of ZnTe films and heterojunctions. CdTe films were deposited on glass and SnO2/glass substrates by metal organic chemical vapor deposition (MOCVD) by reacting dimethylcadmium (DMCd) with diisopropyl tellurium (DITe) in H2. The optical bandgap was 1.50 eV. The conductivity type of the films could be controlled by controlling the DMCd/DITe molar ratio in the reaction mixture. This is a promising technique for the preparation of thin film CdTe homojunction solar cells. CdS films were deposited from aqueous solutions by reacting thiourea and cadmium acetate in an ammonical solution. The films show good optical transmission in the above-bandgap region but are porous and impure. The photovoltaic characteristics of cells employing solution-grown CdS films are therefore inferior to those employing vacuum evaporated CdS films. Films of ZnO, ZnS, and ZnTe were deposited, via MOCVD, on glass and SnO2/glass substrates, and ZnO/ZnTe heterojunctions were produced. Open circuit voltages of 0.6 to 0.7 V were measured for ZnS/ZnTe heterojunctions.

Chu, T. L.

1989-10-01

61

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

62

Chemical Etching of Zinc Oxide for Thin-Film Silicon Solar Cells  

PubMed Central

Abstract Chemical etching is widely applied to texture the surface of sputter-deposited zinc oxide for light scattering in thin-film silicon solar cells. Based on experimental findings from the literature and our own results we propose a model that explains the etching behavior of ZnO depending on the structural material properties and etching agent. All grain boundaries are prone to be etched to a certain threshold, that is defined by the deposition conditions and etching solution. Additionally, several approaches to modify the etching behavior through special preparation and etching steps are provided. PMID:22162035

Hpkes, Jrgen; Owen, Jorj I; Pust, Sascha E; Bunte, Eerke

2012-01-01

63

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

64

Pulse-reverse electrodeposition of transparent nickel phosphide film with porous nanospheres as a cost-effective counter electrode for dye-sensitized solar cells.  

PubMed

A Ni2P nanolayer with porous nanospheres was directly coated on fluorine-doped tin oxide glass by pulse-reverse deposition as a low-cost counter electrode catalyst for dye-sensitized solar cells, and the photoelectron conversion efficiency of the cell was increased to 7.32% by using a porous nanosphere catalyst due to the significantly improved ion transport. PMID:24132176

Wu, Mao-Sung; Wu, Jia-Fang

2013-12-01

65

Zinc Oxide Grown by CVD Process as Transparent Contact for Thin Film Solar Cell Applications  

NASA Astrophysics Data System (ADS)

Metalorganic chemical vapor deposition of ZnO films (MOCVD) [1] started to be comprehensively investigated in the 1980s, when thin film industries were looking for ZnO deposition processes especially useful for large-scale coatings at high growth rates. Later on, when TCO for thin film solar cells started to be developed, another advantage of growing TCO films by the CVD process has been highlighted: the surface roughness. Indeed, a large number of studies on CVD ZnO revealed that an as-grown rough surface cn be obtained with this deposition process [2-4]. A rough surface induces a light scattering effect, which can significantly improve light trapping (and therefore current photo-generation) within thin film silicon solar cells. The CVD process, indeed, directly leads to as-grown rough ZnO films without any post-etching step (the latter is often introduced to obtain a rough surface, when working with as-deposited flat sputtered ZnO). This fact could turn out to be a significant advantage when upscaling the manufacturing process for actual commercial production of thin film solar modules. The zinc and oxygen sources for CVD growth of ZnO films are given in Table 6.1.

Fa, S.; Shah, A.

66

Evaluation of strychnine and zinc phosphide baits to control northern pocket gophers ( Thomomys talpoides) in alfalfa fields in Alberta, Canada  

Microsoft Academic Search

This study compared the effectiveness of Sanex 0.40% strychnine-treated oats, Fairview 0.37% strychnine-treated grains, and United Agri Products 2% zinc phosphide-treated oats to control northern pocket gopher (Thomomys talpoides) populations in alfalfa fields in Alberta, Canada. The poison baits were tested during three phenological periods corresponding to the reproduction, summer juvenile dispersal, and early fall mound building activities. Overall, less

Gilbert Proulx

1998-01-01

67

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

68

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

69

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

70

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

71

Photoelectrochemical cell having photoanode with thin boron phosphide coating as a corrosion resistant layer  

DOEpatents

A surface prone to corrosion in corrosive environments is rendered anticorrosive by CVD growing a thin continuous film, e.g., having no detectable pinholes, thereon, of boron phosphide. In one embodiment, the film is semiconductive. In another aspect, the invention is an improved photoanode, and/or photoelectrochemical cell with a photoanode having a thin film of boron phosphide thereon rendering it anitcorrosive, and providing it with unexpectedly improved photoresponsive properties.

Baughman, Richard J. (Albuquerque, NM); Ginley, David S. (Albuquerque, NM)

1984-01-01

72

Improved fill factors in amorphous silicon solar cells on zinc oxide by insertion of a germanium layer to block impurity incorporation  

E-print Network

Improved fill factors in amorphous silicon solar cells on zinc oxide by insertion of a germanium 80401 (Received 22 September 2003; accepted 25 May 2004) Amorphous silicon based solar cells deposited Institute of Physics. [DOI: 10.1063/1.1773372] The performance of hydrogenated amorphous silicon a

73

Window structure for passivating solar cells based on gallium arsenide  

SciTech Connect

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, A. M.

1985-10-01

74

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

75

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

76

Influence of structural variations in push-pull zinc porphyrins on photovoltaic performance of dye-sensitized solar cells.  

PubMed

We designed and synthesized two new zinc porphyrin dyes for dye-sensitized solar cells (DSCs). Subtle molecular structural variation in the dyes significantly influenced the performance of the DSC devices. By utilizing these dyes in combination with a cobalt-based redox electrolyte using a photoanode made of mesoporous TiO2 , we achieved a power conversion efficiency (PCE) of up to 12.0 % under AM 1.5 G (100 mW cm(-2)) simulated solar light. Moreover, we obtained a high PCE of 6.4 % for solid-state dye-sensitized solar cells by using 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene as a hole-transporting material. PMID:24616370

Yi, Chenyi; Giordano, Fabrizio; Cevey-Ha, Ngoc-Le; Tsao, Hoi Nok; Zakeeruddin, Shaik M; Grtzel, Michael

2014-04-01

77

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

78

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

79

Monitoring structural dynamics of in situ spray-deposited zinc oxide films for application in dye-sensitized solar cells.  

PubMed

The spray-deposition technique is an effective and scalable method to deposit zinc oxide nanostructures, which are used as active layers for dye-sensitized solar cells (DSSCs) in the present study. The dynamics of structural evolution are studied with grazing incidence small-angle X-ray scattering during in situ spraying. Nanostructured films obtained through multiple spray shots provide suitable structural length scales, morphologies, and film thicknesses; this leads to reasonable performance in a DSSC with the highest short-circuit current density reported so far. PMID:24954672

Sarkar, Kuhu; Braden, Erik V; Pogorzalek, Stefan; Yu, Shun; Roth, Stephan V; Mller-Buschbaum, Peter

2014-08-01

80

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

81

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

82

Optimizing the photovoltage of polymer/zinc oxide hybrid solar cells by calcium doping  

NASA Astrophysics Data System (ADS)

The voltage produced by an excitonic solar cell, such as an organic or a hybrid organic/inorganic solar cell is limited by the difference in potential energy between the state occupied by the electron in the acceptor (conduction band minimum (CBM)/lowest unoccupied molecular orbital) and that occupied by the hole in the donor (valence band maximum/highest occupied molecular orbital). Calcium doping of sol-gel ZnO has been used to change the electron affinity of the ZnO acceptor in ZnO/poly(3-hexyl thiophene) hybrid solar cells. The band gap of the mixed oxide system increases with Ca fraction, with most of this attributable to movement of the conduction band minimum toward the vacuum, as determined by UV-vis spectroscopy and Kelvin probe. In planar bilayer cells using Zn0.9Ca0.1O as the acceptor, the open circuit voltage can be increased by 0.24 V, and the efficiency doubled compared to devices using pure ZnO.

Wang, Mingqing; Sun, Jon-Paul; Suei, Sandy; Hill, Ian G.

2012-08-01

83

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

E-print Network

of zinc oxide at atmospheric pressure and low temperature M.D. Barankin, E. Gonzalez II, A.M. Ladwig, R vapor deposition of aluminum-doped zinc oxide has been demonstrated for the first time at 800 Torr reserved. Keywords: Transparent-conducting oxide (TCO); Al/ZnO; PECVD 1. Introduction Aluminum-doped zinc

Hicks, Robert F.

84

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

85

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

86

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

87

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

88

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

89

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

NASA Astrophysics Data System (ADS)

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)2?2H2O), ferric nitrate nonahydrate (Fe(NO3)3?9H2O), iron(III) acetate; Fe(C2H3O2)3, and zinc nitrate hexahydrate, Zn(NO3)2?6H2O. 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.

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

2013-06-01

90

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

91

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, Iporn; Promarak, Vinich

2014-09-29

92

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

93

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

94

Suppression of zinc dendrites in zinc electrode power cells  

NASA Technical Reports Server (NTRS)

Addition of various tetraalkyl quarternary ammonium salts, to alkaline zincate electrolyte of cell, prevents formation of zinc dendrites during charging of zinc electrode. Electrode capacity is not impaired and elimination of dendrites prolongs cell life.

Damjanovic, A.; Diggle, J. W.

1970-01-01

95

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

96

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

97

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

98

Solar Cells  

NASA Technical Reports Server (NTRS)

The Heat Exchanger Method (HEM) produces high efficiency crystal ingots in an automated well-insulated furnace offering low equipment, labor and energy costs. The "grown" silicon crystals are used to make solar cells, or photovoltaic cells which convert sunlight directly into electricity. The HEM method is used by Crystal Systems, Inc. and was developed under a NASA/Jet Propulsion Laboratory contract. The square wafers which are the result of the process are sold to companies manufacturing solar panels.

1983-01-01

99

Routes to copper zinc tin sulfide Cu2ZnSnS4 a potential material for solar cells.  

PubMed

Power generation through photovoltaics (PV) has been growing at an average rate of 40% per year over the last decade; but has largely been fuelled by conventional Si-based technologies. Such cells involve expensive processing and many alternatives use either toxic, less-abundant and or expensive elements. Kesterite Cu(2)ZnSnS(4) (CZTS) has been identified as a solar energy material composed of both less toxic and more available elements. Power conversion efficiencies of 8.4% (vacuum processing) and 10.1% (non-vacuum processing) from cells constructed using CZTS have been achieved to date. In this article, we review various deposition methods for CZTS thin films and the synthesis of CZTS nanoparticles. Studies of direct relevance to solar cell applications are emphasised and characteristic properties are collated. PMID:22531115

Ramasamy, Karthik; Malik, Mohammad A; O'Brien, Paul

2012-06-11

100

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

101

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

102

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

103

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

104

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

105

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

106

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

107

Occupational phosphine gas poisoning at veterinary hospitals from dogs that ingested zinc phosphide--Michigan, Iowa, and Washington, 2006-2011.  

PubMed

Zinc phosphide (Zn3P2) is a readily available rodenticide that, on contact with stomach acid and water, produces phosphine (PH3), a highly toxic gas. Household pets that ingest Zn3P2 often will regurgitate, releasing PH3 into the air. Veterinary hospital staff members treating such animals can be poisoned from PH3 exposure. During 2006-2011, CDC's National Institute for Occupational Safety and Health (NIOSH) received reports of PH3 poisonings at four different veterinary hospitals: two in Michigan, one in Iowa, and one in Washington. Each of the four veterinary hospitals had treated a dog that ingested Zn3P2. Among hospital workers, eight poisoning victims were identified, all of whom experienced transient symptoms related to PH3 inhalation. All four dogs recovered fully. Exposure of veterinary staff members to PH3 can be minimized by following phosphine product precautions developed by the American Veterinary Medical Association (AVMA). Exposure of pets, pet owners, and veterinary staff members to PH3 can be minimized by proper storage, handling, and use of Zn3P2 and by using alternative methods for gopher and mole control, such as snap traps. PMID:22534761

2012-04-27

108

Novel zinc porphyrin sensitizers for dye-sensitized solar cells: Synthesis and spectral, electrochemical, and photovoltaic properties  

NASA Astrophysics Data System (ADS)

Two donor-?-spacer-acceptor porphyrin dyes were synthesized for use in dye-sensitized solar cells. The dyes comprised the same donor (porphyrin derivative) consisting of 3,4,5-trimethoxybenzaldehyde and acceptor/anchoring group (carboxyl group) but varying ?-spacer consisting of a Schiff base structure. Each of the dyes displayed different adsorption behavior and coverage on the TiO2 surface. The porphyrin dyes PZnsbnd BIAsbnd COOH studied in this work exhibit red-shifted and broadened electronic spectra respect to the reference PZnsbnd COOH as expected. By the introduction of Schiff base unit at the meso positions, the energy level of Eox (excited-state oxidation potentials) is significantly shifted to the positive compared with the reference PZnsbnd COOH, indicating a decreased HOMO-LUMO gap. The highest power conversion efficiency of the two dyes based on DSSCs reached 1.75% under AM 1.5 G irradiation.

Tan, Qinglong; Zhang, Xuejun; Mao, Lijun; Xin, Guanqiong; Zhang, Shuanfen

2013-03-01

109

Solarthermal and solar quasi-electrolytic processing and separations: Zinc from zinc oxide as an example  

Microsoft Academic Search

The advantages of using the high thermodynamic potential of sunlight for energy-intensive industrial solar thermochemical and thermoelectrochemical processing and the concomitant need for high-temperature separation methods are discussed. Example applications are introduced. The production of zinc from zinc oxide is used as an explicit illustrative example to show some opportunities and problems that solar energy presents. The use of quasi-electrolysis,

Edward A. Fletcher

1999-01-01

110

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

111

Nanowire-based All Oxide Solar Cells  

SciTech Connect

We present an all-oxide solar cell fabricated from vertically oriented zinc oxide nanowires and cuprous oxide nanoparticles. Our solar cell consists of vertically oriented n-type zinc oxide nanowires, surrounded by a film constructed from p-type cuprous oxide nanoparticles. Our solution-based synthesis of inexpensive and environmentally benign oxide materials in a solar cell would allow for the facile production of large-scale photovoltaic devices. We found that the solar cell performance is enhanced with the addition of an intermediate oxide insulating layer between the nanowires and the nanoparticles. This observation of the important dependence of the shunt resistance on the photovoltaic performance is widely applicable to any nanowire solar cell constructed with the nanowire array in direct contact with one electrode.

Yang*, Benjamin D. Yuhas and Peidong; Yang, Peidong

2008-12-07

112

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

113

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

114

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

115

Development of GaAs solar cells  

NASA Technical Reports Server (NTRS)

Solar cells and mesa diodes were fabricated by the implantation of zinc or beryllium ions into n-type gallium arsenide. Annealing temperatures above 750 C (zinc) or 650 C (beryllium) were found to produce 50% to 100% activation of the implanted ions. Junction depths of about 0.4 micron were produced by 600 keV zinc implants or 70 keV beryllium implants. P-layer sheet resistance was about 150 ohms for 2 x 10 to the 15th power cm/2 zinc or 1 x 10 to the 15th power cm/2 beryllium implants. This is sufficiently low for efficient solar cell fabrication. Contacting procedures were improved to yield reproducibly adherent, low resistance front and back contacts.

1972-01-01

116

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.

117

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

118

Photoelectronic properties of zinc phosphide crystals, films, and heterojunctions. Quarterly progress report No. 11, October 1-December 31, 1981  

SciTech Connect

Variations in crystal growth techniques are continuing with the goal of: (1) improving single crystal quality; and (2) producing variations in crystal properties by doping and post-growth variations of stoichiometry. DLTS measurements using Mg/Zn/sub 3/P/sub 2/ Schottky diodes gave information on three deep levels between 0.55 and 0.66 eV above the valence band in sublimation grown crystals with densities in the 10/sup 15/ to 10/sup 16/ cm/sup -3/ range, and a shallower level at 0.12 eV with a density of 10/sup 15/ cm/sup -3/ in an iodine-transport grown crystal. Investigation of surface properties of Zn/sub 3/P/sub 2/ indicate that a Br-MeOH etch leaves a Zn-rich surface for both sublimation-grown and iodine-transport grown crystals. Detailed measurements were made on thick Mg/Zn/sub 3/P/sub 2/ junctions on sublimation-grown and iodine-transport grown crystals of log J-V characteristics as a function of temperature, for crystal substrates as etched, and after heat treatment in hydrogen at several temperatures. A systematic change in the junction transport mechanism from tunneling at heat-treatment temperatures less than 300/sup 0/C to recombination/generation for heat-treatment temperatures between 300 and 500/sup 0/C was found for Zn/sub 3/P/sub 2/ crystals grown by both growth techniques. A simple model involving a depletion of free carrier density near the surface as a result of heat treatment in hydrogen is proposed. Thin film Mg/Zn/sub 3/P/sub 2/ cells showed log J-V characteristics that are strongly light dependent, indicating an increase in tunneling with illumination. Evidence that the barrier height of the Mg/Zn/sub 3/P/sub 2/ junction is actually of the order of 0.9 to 1.0 eV was obtained. Attempts to prepare ITO/Zn/sub 3/P/sub 2/ junctions by electron-beam evaporation of ITO on single crystal substrates yielded poor diodes and negligible photovoltaic behavior.

Bube, R.H.

1981-01-01

119

Synthesis of p-iron(III) oxide, n-iron(III) oxide, and carbon-modified-n-titanium dioxide and their application in self-driven photoelectrochemical cells: p-iron(III) oxide/n-iron(III) oxide, p-iron(III) oxide/carbon-modified-n-titanium dioxide, and p-gallium indium phosphide/carbon-modified-n-titanium dioxide for direct water photoelectrolysis  

NASA Astrophysics Data System (ADS)

My Ph.D. Dissertation describes (1) the influence of metal dopants on the spray pyrolytic synthesis of p-type and n-type iron(III) oxide thin film semiconductors, (2) the fabrication of carbon-modified (CM) n-type titanium dioxide, and (3) various self-driven photoelectrochemical cells (PEC) for water splitting. (1) Stable thin films of iron(III) oxide was the first goal pursued in this work. Various metal dopants were investigated to ascertain their viability as good dopant for iron(III) oxide. These metals included copper, zinc, and magnesium. This was followed by investigating metals that could improve the conductivity of n-type iron(III) oxide, which included indium, iodine, manganese, and calcium. Research showed that zinc improved p-type characteristics the best, and considerably improved stability of p-type iron(III) oxide in acidic media. Indium-doped n-type iron(III) oxide showed improvement in photocurrent response over naturally-doped iron(III) oxide; however, there was a loss in the onset potential, which proved vital for developing a self-driven PEC. Importantly, the use of 1-pentanol as the spray solution solvent instead of ethanol improved the onset potential and photoresponse of n-type iron(III) oxide which helped to fabricate a self-driven p-type/n-type iron(III) oxide PEC for water splitting. (2) Carbon-modified n-type titanium dioxide electrodes were found to be extremely valuable towards fabrication of self-driven water splitting PEC, because the addition of carbon into the titanium dioxide crystal structure provided it with the ability to absorb light much further into the visible spectrum. Unmodified titanium dioxide can only absorb 13% of the total solar power (100 mW/cubic cm) of Air Mass (AM) 1.5; in other words wavelengths of light from ultraviolet to 414 nm. Carbon modification of n-type titanium dioxide allows it to absorb up to 535 nm, or 30% of the total solar power. (3) The most important part of this work is the fabrication of a self-driven PEC for water splitting using zinc-doped p-type iron(III) oxide and naturally-doped n-type iron(III) oxide; carbon-modified n-type titanium dioxide and zinc-doped p-type iron(III) oxide; and p-type gallium indium phosphide and carbon-modified n-type titanium dioxide.

Ingler, William B., Jr.

120

The silicon/zinc oxide interface in amorphous silicon-based thin-film solar cells: Understanding an empirically optimized contact  

NASA Astrophysics Data System (ADS)

The electronic structure of the interface between the boron-doped oxygenated amorphous silicon "window layer" (a-SiOx:H(B)) and aluminum-doped zinc oxide (ZnO:Al) was investigated using hard x-ray photoelectron spectroscopy and compared to that of the boron-doped microcrystalline silicon (?c-Si:H(B))/ZnO:Al interface. The corresponding valence band offsets have been determined to be (-2.87 0.27) eV and (-3.37 0.27) eV, respectively. A lower tunnel junction barrier height at the ?c-Si:H(B)/ZnO:Al interface compared to that at the a-SiOx:H(B)/ZnO:Al interface is found and linked to the higher device performances in cells where a ?c-Si:H(B) buffer between the a-Si:H p-i-n absorber stack and the ZnO:Al contact is employed.

Gerlach, D.; Wilks, R. G.; Wippler, D.; Wimmer, M.; Lozac'h, M.; Flix, R.; Mck, A.; Meier, M.; Ueda, S.; Yoshikawa, H.; Gorgoi, M.; Lips, K.; Rech, B.; Sumiya, M.; Hpkes, J.; Kobayashi, K.; Br, M.

2013-07-01

121

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

122

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

123

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

124

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

125

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

126

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

127

A GaAs/GaInP dual junction solar cell grown by molecular beam epitaxy  

NASA Astrophysics Data System (ADS)

We report the recent result of GaAs/GaInP dual-junction solar cells grown by all solid-state molecular-beam-epitaxy (MBE). The device structure consists of a GaIn0.48P homojunction grown epitaxially upon a GaAs homojunction, with an interconnected GaAs tunnel junction. A photovoltaic conversion efficiency of 27% under the AM1.5 globe light intensity is realized for a GaAs/GaInP dual-junction solar cell, while the efficiencies of 26% and 16.6% are reached for a GaAs bottom cell and a GaInP top cell, respectively. The energy loss mechanism of our GaAs/GaInP tandem dual-junction solar cells is discussed. It is demonstrated that the MBE-grown phosphide-containing IIIV compound semiconductor solar cell is very promising for achieving high energy conversion efficiency.

Pan, Dai; Shulong, Lu; Lian, Ji; Wei, He; Lifeng, Bian; Hui, Yang; Arimochi, M.; Yoshida, H.; Uchida, S.; Ikeda, M.

2013-10-01

128

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

129

The silicon/zinc oxide interface in amorphous silicon-based thin-film solar cells: Understanding an empirically optimized contact  

SciTech Connect

The electronic structure of the interface between the boron-doped oxygenated amorphous silicon 'window layer' (a-SiO{sub x}:H(B)) and aluminum-doped zinc oxide (ZnO:Al) was investigated using hard x-ray photoelectron spectroscopy and compared to that of the boron-doped microcrystalline silicon ({mu}c-Si:H(B))/ZnO:Al interface. The corresponding valence band offsets have been determined to be (-2.87 {+-} 0.27) eV and (-3.37 {+-} 0.27) eV, respectively. A lower tunnel junction barrier height at the {mu}c-Si:H(B)/ZnO:Al interface compared to that at the a-SiO{sub x}:H(B)/ZnO:Al interface is found and linked to the higher device performances in cells where a {mu}c-Si:H(B) buffer between the a-Si:H p-i-n absorber stack and the ZnO:Al contact is employed.

Gerlach, D.; Wilks, R. G.; Wimmer, M.; Felix, R.; Gorgoi, M.; Lips, K.; Rech, B. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Wippler, D.; Mueck, A.; Meier, M.; Huepkes, J. [Institut fuer Energie- und Klimaforschung, Forschungszentrum Juelich GmbH, Wilhelm-Johnen-Strasse, D-52428 Juelich (Germany); Lozac'h, M.; Ueda, S.; Sumiya, M. [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Yoshikawa, H. [Synchrotron X-ray Station at SPring-8, NIMS, Kouto 1-1-1, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Kobayashi, K. [Quantum Beam Science Directorate, Japan Atomic Energy Agency, Kouto 1-1-1, SPring-8, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Baer, M. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Institut fuer Physik und Chemie, Brandenburgische Technische Universitaet Cottbus, Konrad-Wachsmann-Allee 1, D-03046 Cottbus (Germany)

2013-07-08

130

Measuring solar-cell quality  

NASA Technical Reports Server (NTRS)

Automatic checking system illuminates solar cells to ensure minority carrier lifetime is at proper value. Testing method promises to make solar cell manufacture more economical, efficient and reliable.

Von Roos, O.

1977-01-01

131

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

132

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

133

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

134

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

135

Investigation of surface phase formation during tin-rich growth of Copper2ZincTinSulfer4 polycrystlalline thin films for solar cells  

NASA Astrophysics Data System (ADS)

Cu2ZnSnS4 (CZTS) is a semiconductor material made of nontoxic, earth abundant elements, making it a promising topic of research for absorber layers in thin film solar cells. We observed that rapid thermal annealing of tin (Sn)-rich co-sputtered CZTS films resulted in crystalline, hexagonal platelets of tin-disulfide (SnS2) 5-30 m long at the surface of the film. In this work, the formation mechanisms of these surface crystallites and their implications for CZTS absorber layer processing were investigated. The formation and decomposition of these platelets were studied by observing the changes in their structural, morphological, compositional, and vibrational properties accompanying the imposition of lateral temperature gradients as well as different annealing atmospheres. The homogeneous co-sputtered films were annealed in a graphite boat in a quartz reactor using a base heater and halogen lamp. Interrupting annealings to examine stages of crystal formation showed at around 400 C SnS2 began to form on the surface of films. Near the edges of the film, where temperatures were found to be higher, crystals melted into an amorphous unknown tin-sulfide phase. Diffusion of species from the film into the base of the crystals formed long CZTS grains of which the amorphous phase left behind as it coalesced. Annealing without sulfur (S) increased Sn and S losses from the film and increased the number of crystals nucleated on the surface of the film. For solar cell device applications of CZTS thin films, removal of these SnS2 surface crystallites is necessary; thus wet chemical and thermal decomposition etching techniques were studied. Wet etching attempts with KCN and NH4OH solutions did little to etch crystals. HCl solution damaged the CZTS film as much as the crystals and therefore was also unsuitable. Thermal etching by evacuating the chamber near the end of annealing transformed the SnS2 crystals into a grainy, S-poor Sn phase via the decomposition of SnS2 by removing the vapor species with which it is in equilibrium. Understanding the role of Sn species during annealing is important for the complex CZTS system because small deviations from Sn stoichiometry results in drastic changes in the secondary phases and microstructure of the film. The experiments and insight provided in this thesis represent unexplored unconventional methods toward CZTS growth and different approaches for CZTS processing for development of thin film solar cell technology.

Bolke, Joseph Glenn

136

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

137

Rechargeable zinc cell with alkaline electrolyte which inhibits shape change in zinc electrode  

DOEpatents

An improved rechargeable zinc cell is described comprising a zinc electrode and another electrode such as, for example, a nickel-containing electrode, and having an electrolyte containing KOH and a combination of KF and K[sub 2]CO[sub 3] salts which inhibits shape change in the zinc electrode, i.e., the zinc electrode exhibits low shape change, resulting in an improved capacity retention of the cell over an number of charge-discharge cycles, while still maintaining high discharge rate characteristics. 8 figures.

Adler, T.C.; McLarnon, F.R.; Cairns, E.J.

1994-04-12

138

Rechargeable zinc cell with alkaline electrolyte which inhibits shape change in zinc electrode  

DOEpatents

An improved rechargeable zinc cell is described comprising a zinc electrode and another electrode such as, for example, a nickel-containing electrode, and having an electrolyte containing KOH and a combination of KF and K.sub.2 CO.sub.3 salts which inhibits shape change in the zinc electrode, i.e., the zinc electrode exhibits low shape change, resulting in an improved capacity retention of the cell over an number of charge-discharge cycles, while still maintaining high discharge rate characteristics.

Adler, Thomas C. (Berkeley, CA); McLarnon, Frank R. (Orinda, CA); Cairns, Elton J. (Walnut Creek, CA)

1994-01-01

139

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

140

Lateral superlattice solar cells  

SciTech Connect

A novel structure which comprises of a lateral superlattice as the active layer of a solar cell is proposed. If the alternating regions A and B of a lateral superlattice ABABAB... are chosen to have a Type-II band offset, it is shown that the performance of the active absorbing region of the solar cell is optimized. In essence, the Type-II lateral superlattice region can satisfy the material requirements for an ideal solar cells active absorbing region, i.e. simultaneously having a very high transition probability for photogeneration and a very long minority carrier recombination lifetime.

Mascarenhas, A.; Zhang, Y. [National Renewable Energy Lab., Golden, CO (United States); Millunchick, J.M.; Twesten, R.D.; Jones, E.D. [Sandia National Labs., Albuquerque, NM (United States)

1997-10-01

141

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

142

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

143

Solar cell array interconnects  

DOEpatents

Electrical interconnects are disclosed 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. 4 figs.

Carey, P.G.; Thompson, J.B.; Colella, N.J.; Williams, K.A.

1995-11-14

144

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

145

Nanocrystal Solar Cells  

SciTech Connect

This dissertation presents the results of a research agenda aimed at improving integration and stability in nanocrystal-based solar cells through advances in active materials and device architectures. The introduction of 3-dimensional nanocrystals illustrates the potential for improving transport and percolation in hybrid solar cells and enables novel fabrication methods for optimizing integration in these systems. Fabricating cells by sequential deposition allows for solution-based assembly of hybrid composites with controlled and well-characterized dispersion and electrode contact. Hyperbranched nanocrystals emerge as a nearly ideal building block for hybrid cells, allowing the controlled morphologies targeted by templated approaches to be achieved in an easily fabricated solution-cast device. In addition to offering practical benefits to device processing, these approaches offer fundamental insight into the operation of hybrid solar cells, shedding light on key phenomena such as the roles of electrode-contact and percolation behavior in these cells. Finally, all-inorganic nanocrystal solar cells are presented as a wholly new cell concept, illustrating that donor-acceptor charge transfer and directed carrier diffusion can be utilized in a system with no organic components, and that nanocrystals may act as building blocks for efficient, stable, and low-cost thin-film solar cells.

Gur, Ilan

2006-12-15

146

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

147

Screening of solar cells  

NASA Technical Reports Server (NTRS)

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.

1993-01-01

148

Properties of double-layered Ga-doped Al-zinc-oxide/titanium-doped indium-tin-oxide thin films prepared by dc magnetron sputtering applied for Si-based thin film solar cells  

SciTech Connect

In this article, Ga-doped Al-zinc-oxide (GAZO)/titanium-doped indium-tin-oxide (ITIO) bi-layer films were deposited onto glass substrates by direct current (dc) magnetron sputtering. The bottom ITIO film, with a thickness of 200 nm, was sputtered onto the glass substrate. The ITIO film was post-annealed at 350 deg. C for 10-120 min as a seed layer. The effect of post-annealing conditions on the morphologies, electrical, and optical properties of ITIO films was investigated. A GAZO layer with a thickness of 1200 nm was continuously sputtered onto the ITIO bottom layer. The results show that the properties of the GAZO/ITIO films were strongly dependent on the post-annealed conditions. The spectral haze (T{sub diffuse}/T{sub total}) of the GAZO/ITIO bi-layer films increases upon increasing the post-annealing time. The haze and resistivity of the GAZO/ITIO bi-layer films were improved with the post-annealed process. After optimizing the deposition and annealing parameters, the GAZO/ITIO bi-layer film has an average transmittance of 83.20% at the 400-800 nm wavelengths, a maximum haze of 16%, and the lowest resistivity of 1.04 x 10{sup -3}{Omega} cm. Finally, the GAZO/ITIO bi-layer films, as a front electrode for silicon-based thin film solar cells, obtained a maximum efficiency of 7.10%. These encouraging experimental results have potential applications in GAZO/ITIO bi-layer film deposition by in-line sputtering without the wet-etching process and enable the production of highly efficient, low-cost thin film solar cells.

Wang, Chao-Chun; Wuu, Dong-Sing; Lin, Yang-Shih; Lien, Shui-Yang; Huang, Yung-Chuan; Liu, Chueh-Yang; Chen, Chia-Fu; Nautiyal, Asheesh; Lee, Shuo-Jen [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China); Department of Materials Science and Engineering, MingDao University, Changhua 52345, Taiwan (China); Department of Mechanical Engineering, Yuan Ze University, Taoyuan 320, Taiwan (China)

2011-11-15

149

Welded solar cell interconnection  

NASA Technical Reports Server (NTRS)

The efficiency of the welding of solar-cell interconnects is compared with the efficiency of soldering such interconnects, and the cases in which welding may be superior are examined. Emphasis is placed on ultrasonic welding; attention is given to the solar-cell welding machine, the application of the welding process to different solar-cell configurations, producibility, and long-life performance of welded interconnects. Much of the present work has been directed toward providing increased confidence in the reliability of welding using conditions approximating those that would occur with large-scale array production. It is concluded that there is as yet insufficient data to determine which of three methods (soldering, parallel gap welding, and ultrasonic welding) provides the longest-duration solar panel life.

Stofel, E. J.; Browne, E. R.; Meese, R. A.; Vendura, G. J.

1982-01-01

150

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

151

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

152

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.

153

Thin boron phosphide coating as a corrosion-resistant layer  

DOEpatents

A surface prone to corrosion in corrosive environments is rendered anticorrosive by CVD growing a thin continuous film, e.g., having no detectable pinholes, thereon, of boron phosphide. In one embodiment, the film is semiconductive. In another aspect, the invention is an improved photoanode, and/or photoelectrochemical cell with a photoanode having a thin film of boron phosphide thereon rendering it anticorrosive, and providing it with unexpectedly improved photoresponsive properties.

Not Available

1982-08-25

154

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

155

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

156

Amorphous silicon solar cells  

Microsoft Academic Search

The photoconductive response of Schottky-barrier and p-i-n solar cell structures was analyzed. It shows that the photoconductivity determines the fill factor, rather than the dark current, as in crystalline silicon cells. An analysis of the I-V curves of p-i-n cells shows that the electron and hole drift lengths are comparable. High conductivity p and n type films (sigma = 1-10

D. E. Carlson; R. S. Crandall; J. Dresner; D. Goldstein; J. J. Hanak; A. R. Moore; R. E. Schade; D. L. Staebler; H. A. Weakliem; R. Williams

1981-01-01

157

Monolithic tandem solar cell  

SciTech Connect

It is an object of the invention to provide a monolithic tandem photovoltaic solar cell which is highly radiation resistant and efficient; in which the energy bandgap of the lower subcell can be tailored for specific applications; solar cell comprising layers of InP and GaInAsP (or GaInAs), where said photovoltaic cell is useful, for example, in space power applications; having an improved power-to-mass ratio; in which subcells are lattice-matches; and are both two terminal and three terminal monolithic tandem photovoltaic solar cells. To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the monolithic tandem photovoltaic solar cell may comprise; (a) an InP substrate having an upper surface; (b) a first photoactive subcell on the upper surface of the InP substrate; wherein the first subcell comprises GaInAs (which could include GaInAsP) and includes a homojunction; and (c) a second photoactive subcell on the first subcell; wherein the second subcell comprises InP and includes a homojunction. The cell is described in detail. 5 figs., 2 tabs.

Wanlass, M.W.

1989-11-03

158

Design, characterization and fabrication of silicon solar cells for ?50% efficient 6-junction tandem solar cells  

Microsoft Academic Search

A major objective for photovoltaic conversion is to develop high efficiency solar cells. Many approaches are under investigation - Multiple Junction Solar Cell, Multiple Spectrum Solar Cell, Multiple Absorption Path Solar Cell, Multiple Energy Solar Cell, and Multiple Temperature Solar Cells [1]. The Multiple Junction Solar Cell approach based on a six-junction tandem solar cell has been adopted to achieve

Ngwe Soe Zin; Andrew Blakers; Evan Franklin; Vernie Everett

2008-01-01

159

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, and (c) a second photoactive subcell on the first subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched. The solar cell can be provided as a two-terminal device or a three-terminal device.

Wanlass, Mark W. (Golden, CO)

1991-01-01

160

Monolithic tandem solar cell  

SciTech Connect

This patent describes a single-crystal, monolithic, tandem, photovoltaic solar cell which includes an InP substrate having an upper and lower surfaces, a first photoactive subcell on the upper surface of the InP substrate, and a second photoactive subcell on the first subcell. The first photovoltaic subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched. The solar cell can be provided as a two- terminal device or a three-terminal device.

Wanlass, M.W.

1991-05-28

161

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

162

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

163

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

164

Diffusion length variation and proton damage coefficients for InP/In(x)Ga(1-x)As/GaAs solar cells  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

165

Thin, Lightweight Solar Cell  

NASA Technical Reports Server (NTRS)

Improved design for thin, lightweight solar photovoltaic cells with front contacts reduces degradation of electrical output under exposure to energetic charged particles (protons and electrons). Increases ability of cells to maintain structural integrity under exposure to ultraviolet radiation by eliminating ultraviolet-degradable adhesives used to retain cover glasses. Interdigitated front contacts and front junctions formed on semiconductor substrate. Mating contacts formed on back surface of cover glass. Cover glass and substrate electrostatically bonded together.

Brandhorst, Henry W., Jr.; Weinberg, Irving

1991-01-01

166

Surface passivation of InP solar cells with InAlAs layers  

NASA Technical Reports Server (NTRS)

The efficiency of indium phosphide solar cells is limited by high values of surface recombination. The effect of a lattice-matched In(0.52)Al(0.48)As window layer material for InP solar cells, using the numerical code PC-1D is investigated. It was found that the use of InAlAs layer significantly enhances the p(+)n cell efficiency, while no appreciable improvement is seen for n(+)p cells. The conduction band energy discontinuity at the heterojunction helps in improving the surface recombination. An optimally designed InP cell efficiency improves from 15.4 percent to 23 percent AMO for a 10 nm thick InAlAs layer. The efficiency improvement reduces with increase in InAlAs layer thickness, due to light absorption in the window layer.

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

1993-01-01

167

Solar cell coverslide extraction apparatus  

Microsoft Academic Search

This patent describes an apparatus for extracting a coverslide from a solar cell in a solar cell module. The coverslide is adhered to the solar cell by a dissolvable layer of adhesive along a predetermined plane of attachment. The apparatus comprises: (a) a receptacle having a cavity defined therein; (b) a rack disposed in the cavity of the receptacle; (c)

1987-01-01

168

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

169

Fatal aluminum phosphide poisoning.  

PubMed

A 39-year-old man committed suicide by ingestion of aluminum phosphide, a potent mole pesticide, which was available at the victim's workplace. The judicial authority ordered an autopsy, which ruled out any other cause of death. The victim was discovered 10 days after the ingestion of the pesticide. When aluminum phosphide comes into contact with humidity, it releases large quantities of hydrogen phosphine (PH3), a very toxic gas. Macroscopic examination during the autopsy revealed a very important asphyxia syndrome with major visceral congestion. Blood, urine, liver, kidney, adrenal, and heart samples were analyzed. Phosphine gas was absent in the blood and urine but present in the brain (94 mL/g), the liver (24 mL/g), and the kidneys (41 mL/g). High levels of phosphorus were found in the blood (76.3 mg/L) and liver (8.22 mg/g). Aluminum concentrations were very high in the blood (1.54 mg/L), brain (36 microg/g), and liver (75 microg/g) compared to the usual published values. Microscopic examination revealed congestion of all the organs studied and obvious asphyxia lesions in the pulmonary parenchyma. All these results confirmed a diagnosis of poisoning by aluminum phosphide. This report points out that this type of poisoning is rare and that hydrogen phosphine is very toxic. The phosphorus and aluminum concentrations observed and their distribution in the different viscera are discussed in relation to data in the literature. PMID:10732945

Anger, F; Paysant, F; Brousse, F; Le Normand, I; Develay, P; Gaillard, Y; Baert, A; Le Gueut, M A; Pepin, G; Anger, J P

2000-03-01

170

Rechargeable zinc cell with alkaline electrolyte which inhibits shape change in zinc electrode  

DOEpatents

An improved rechargeable zinc cell is described comprising a zinc electrode and another electrode such as, for example, a nickel-containing electrode, and having an electrolyte containing one or more hydroxides having the formula M(OH), one or more fluorides having the formula MF, and one or more carbonates having the formula M.sub.2 CO.sub.3, where M is a metal selected from the group consisting of alkali metals. The electrolyte inhibits shape change in the zinc electrode, i.e., the zinc electrode exhibits low shape change, resulting in an improved capacity retention of the cell over an number of charge-discharge cycles, while still maintaining high discharge rate characteristics.

Adler, Thomas C. (Berkeley, CA); McLarnon, Frank R. (Orinda, CA); Cairns, Elton J. (Walnut Creek, CA)

1995-01-01

171

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...

172

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.

173

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

174

Potential for use of InP solar cells in the space radiation environment  

NASA Technical Reports Server (NTRS)

Indium phosphide solar cells were observed to have significantly higher radiation resistance than either GaAs or Si after exposure to 10 MeV proton irradiation data and previous 1 MeV electron data together with projected efficiencies for InP, it was found that these latter cells produced more output power than either GaAs or Si after specified fluences of 10 MeV protons and 1 MeV electrons. Estimates of expected performance in a proton dominated space orbit yielded much less degradation for InP when compared to the remaining two cell types. It was concluded that, with additional development to increase efficiency, InP solar cells would perform significantly better than either GaAs or Si in the space radiation environment.

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

1985-01-01

175

Very high efficiency solar cells  

NASA Astrophysics Data System (ADS)

The Defense Advanced Research Projects Agency has initiated the Very High Efficiency Solar Cell (VHESC) program to address the critical need of the soldier for power in the field. Very High Efficiency Solar Cells for portable applications that operate at greater than 55 percent efficiency in the laboratory and 50 percent in production are being developed. We are integrating the optical design with the solar cell design, and have entered previously unoccupied design space that leads to a new architecture paradigm. An integrated team effort is now underway that requires us to invent, develop and transfer to production these new solar cells. Our approach is driven by proven quantitative models for the solar cell design, the optical design and the integration of these designs. We start with a very high performance crystalline silicon solar cell platform. Examples will be presented. Initial solar cell device results are shown for devices fabricated in geometries designed for this VHESC Program.

Barnett, Allen; Kirkpatrick, Douglas; Honsberg, Christiana

2006-08-01

176

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

177

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

178

Quantum Dot Solar Cells  

NASA Astrophysics Data System (ADS)

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.

2002-10-01

179

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

180

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

181

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

182

Human ZIP1 is a major zinc uptake transporter for the accumulation of zinc in prostate cells  

Microsoft Academic Search

The prostate gland of humans and other animals accumulates a level of zinc that is 310 times greater than that found in other tissues. Associated with this ability to accumulate zinc is a rapid zinc uptake process in human prostate cells, which we previously identified as the hZIP1 zinc transporter. We now provide additional evidence that hZIP1 is an important

R. B. Franklin; J. Ma; J. Zou; Z. Guan; B. I. Kukoyi; P. Feng; L. C. Costello

2003-01-01

183

Superlattice cascade solar cell  

SciTech Connect

This paper reports progress toward realization of a new cascade solar cell structure whose chief advantages over other present concepts are: use of silicon for the substrate and low bandgap cell; avoidance of the necessity of lattice matching; and incorporation of a GaAs/GaP superlattice to enhance efficiency and provide a low-resistance connecting junction. Details of the design and operation of an OMCVD system for growing this structure are presented. Results of experiments to optimize layer thickness, compositional uniformity, and surface morphology are described.

Wanlass, M.W.; Blakeslee, A.E.

1982-09-01

184

Zinc  

MedlinePLUS

... generally increase zinc absorption, although a protein in cow's milk slows absorption down. Soy proteins also reduce ... the most zinc from mother's milk, less from cow's milk, and even less from soy-based milk. ...

185

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

186

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

187

OSMIUM ZINC IODIDE REACTIVE SITES IN THE EPIDERMAL LANGERHANS CELL  

Microsoft Academic Search

Fixation of epidermis with a mixture of osmium tetroxide and zinc iodide (Os0 4-ZnI2) for 24 hr renders the central periodic lamella of the Langerhans cell granule (LCG), the Golgi region, and the nuclear envelope of epidermal Langerhans cells preferentially visible . The use of this technique on Langerhans cells in normal epidermis and in epidermis of patients with histiocytosis

GUSTAV NIEBAUER; RICHARD L. KIDD; GEORGE F. WILGRAM

2009-01-01

188

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

189

Advancing tandem solar cells by spectrally selective multilayer intermediate reflectors.  

PubMed

Thin-film silicon tandem solar cells are composed of an amorphous silicon top cell and a microcrystalline silicon bottom cell, stacked and connected in series. In order to match the photocurrents of the top cell and the bottom cell, a proper photon management is required. Up to date, single-layer intermediate reflectors of limited spectral selectivity are applied to match the photocurrents of the top and the bottom cell. In this paper, we design and prototype multilayer intermediate reflectors based on aluminum doped zinc oxide and doped microcrystalline silicon oxide with a spectrally selective reflectance allowing for improved current matching and an overall increase of the charge carrier generation. The intermediate reflectors are successfully integrated into state-of-the-art tandem solar cells resulting in an increase of overall short-circuit current density by 0.7 mA/cm(2) in comparison to a tandem solar cell with the standard single-layer intermediate reflector. PMID:25322181

Hoffmann, Andre; Paetzold, Ulrich W; Zhang, Chao; Merdzhanova, Tsvetelina; Lambertz, Andreas; Ulbrich, Carolin; Bittkau, Karsten; Rau, Uwe

2014-08-25

190

Zinc and zinc chelators modify taurine transport in rat retinal cells.  

PubMed

Zinc regulates Na(+)/Cl(-)-dependent transporters, similar to taurine one, such as those for dopamine, serotonin and norepinephrine. This study examined the ex vivo effect of zinc (ZnSO4), N,N,N,N-tetraquis-(2-piridilmetil)etilendiamino (TPEN) and diethylenetriaminepenta-acetic acid (DTPA), intracellular and extracellular zinc chelators, respectively, on rat retina [(3)H]taurine transport. Isolated cells were incubated in Locke solution with 100 nM of [(3)H]taurine for 25 s. Different concentrations of ZnSO4 (0.5-200 ?M) were used. Low concentrations of ZnSO4 (30 and 40 ?M) increased the transport, while higher concentrations (100, 150 and 200 ?M) decreased it. Various concentrations of TPEN (1-200 ?M) were added. Intermediate concentrations of TPEN (10-60 ?M) significantly decreased [(3)H]taurine transport. The presence of TPEN, 20 ?M, plus ZnSO4 reversed the effect of TPEN alone. Several concentrations of DTPA (1-500 ?M) were also investigated. Reduction of transport took place at high concentrations of the chelator (100, 250 and 500 ?M). DTPA, 500 ?M, plus ZnSO4, did not modify the effect of it. These results indicate that zinc modulates taurine transport in a concentration-dependent manner, directly acting on the transporter or by forming taurine-zinc complexes in cell membranes. PMID:25182776

Mrquez, Asar; Urbina, Mary; Lima, Lucimey

2014-11-01

191

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

192

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 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.

Wanlass, Mark W. (Golden, CO)

1994-01-01

193

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

194

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

PubMed

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

Lu, Shulong; Ji, Lian; He, Wei; Dai, Pan; Yang, Hui; Arimochi, Masayuki; Yoshida, Hiroshi; Uchida, Shiro; Ikeda, Masao

2011-01-01

195

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...

196

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

197

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

198

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

199

Thin film solar cell workshop  

NASA Technical Reports Server (NTRS)

A summation of responses to questions posed to the thin-film solar cell workshop and the ensuing discussion is provided. Participants in the workshop included photovoltaic manufacturers (both thin film and crystalline), cell performance investigators, and consumers.

Armstrong, Joe; Jeffrey, Frank

1993-01-01

200

Zinc-oxygen primary cell yields high energy density  

NASA Technical Reports Server (NTRS)

Zinc-oxygen primary cell yields high energy density for battery used as an auxiliary power source in space vehicle systems. Maximum reliability and minimum battery weight is achieved by using a stacking configuration of 23 series-connected modules with 6 parallel-connected cells per module.

Graff, C. B.

1968-01-01

201

An Introduction to Solar Cells  

ERIC Educational Resources Information Center

Most likely, solar cells will play a significant role in this country's strategy to address the two interrelated issues of global warming and dependence on imported oil. The purpose of this paper is to present an explanation of how solar cells work at an introductory high school, college, or university physics course level. The treatment presented

Feldman, Bernard J.

2010-01-01

202

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

2015-02-01

203

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

204

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

205

Screening-Engineered Field-Effect Solar Cells William Regan,,,  

E-print Network

the promising but hard-to-dope metal oxides, sulfides, and phosphides.3 Prototype SFPV devices have been at the MIS interface. Unfortu- nately, MIS cells, though sporting impressive efficiencies,4-6 typically have at direct field- effect "doping" of semiconductors, in which the voltage is externally applied to a gate

Zettl, Alex

206

Thermophotovoltaic Cells on Zinc Diffused Polycrystalline GaSb  

SciTech Connect

For the first time, it has been demonstrated that thermophotovoltaic cells made of polycrystalline GaSb with small grain sizes (down to 100 x 100 {micro}m) have similar characteristics to the best Zinc diffused single crystal GaSb cells with identified device parameters. The grain boundaries in polycrystalline GaSb do not degrade TPV cell parameters, indicating that such material can be used for high-efficiency thermophotovoltaic cells.

Sulima, O.V.; Bett, A.W.; Dutta, P.S.; Ehsani, H.; Gutmann, R.J.

2000-05-01

207

Overexpression of the ZIP1 zinc transporter induces an osteogenic phenotype in mesenchymal stem cells  

Microsoft Academic Search

Zinc is an essential trace element that is involved in diverse metabolic and signaling pathways. Zinc deficiency is associated with retardation of bone growth. Previous in vitro studies have suggested a direct effect of zinc on both the proliferation and differentiation of osteoblast-like cells. However, the mechanisms for uptake of zinc into osteoblasts have not been examined in detail. Several

Zhihui Tang; Surasri Nandan Sahu; Mohammed Abdul Khadeer; Guang Bai; Renty B. Franklin; Anandarup Gupta

2006-01-01

208

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

209

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

210

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

211

Sealed silver oxide zinc cells for orbiting and planetary missions.  

NASA Technical Reports Server (NTRS)

Several test programs were carried out to determine the performance and limitations of sealed, silver oxide zinc cells for (1) 24-hr synchronous orbits, (2) orbits that would require a maximum of six cycles per day, and (3) missions to other planets requiring maintenance of maximum capacity for probe operations during planet encounter. The results are summarized to provide power system designers with guidelines bearing on capacity maintenance during cycling, cycle life, charged stand effects, and internal pressure characteristics. The life of zinc silver oxide cells is shown to be limited to one to two years over the temperature range of 0 to 24 C.

Hennigan, T. J.; Palandati, C. F.

1972-01-01

212

Mechanically refuelable zinc/air electric vehicle cells  

NASA Astrophysics Data System (ADS)

Refuelable zinc/air batteries have long been considered for motive as well as stationary power because of a combination of high specific energy, low initial cost, and the possibility of mechanical recharge by electrolyte exchange and additions of metallic zinc. In this context, advanced slurry batteries, stationary packed bed cells, and batteries offering replaceable cassettes have been reported recently. The authors are developing self-feeding, particulate-zinc/air batteries for electric vehicle applications. Emissionless vehicle legislation in California motivated efforts to consider a new approach to providing an electric vehicle with long range (400 km), rapid refueling (10 minutes) and highway safe acceleration - factors which define the essential functions of common automobiles. Such an electric vehicle would not compete with emerging secondary battery vehicles in specialized applications (commuting vehicles, delivery trucks). Rather, different markets would be sought where long range or rapid range extension are important. Examples are: taxis, continuous-duty fork-lift trucks and shuttle busses, and general purpose automobiles having modest acceleration capabilities. In the long range, a mature fleet would best use regional plants to efficiently recover zinc from battery reaction products. One option would be to use chemical/thermal reduction to recover the zinc. The work described focuses on development of battery configurations which efficiently and completely consume zinc particles, without clogging or changing discharge characteristics.

Noring, J.; Gordon, S.; Maimoni, A.; Spragge, M.; Cooper, J. F.

1992-12-01

213

InP shallow-homojunction solar cells  

NASA Technical Reports Server (NTRS)

Indium phosphide solar cells with very thin n-type emitters have been made by both ion implantation and metalorganic chemical vapor deposition. Air mass zero efficiencies as high as 18.8 percent (NASA measurement) have been achieved. Although calculations show that, as is the case with GaAs, a heterostructure is expected to be required for the highest efficiencies attainable, the material properties of InP give the shallow-homojunction structure a greater potential than in the case of GaAs. The best cells, which were those made by ion implantation, show open-circuit voltage (V sub oc) of 873 mV, short-circuit current of 357 A/sq m (35.7 mA/sq cm), and fill factor of 0.829. Improvements are anticipated in all three of these parameters. Internal quantum efficiency peaks at over 90 percent in the red end of the spectrum, but drops to 54 percent in the blue end. Other cells have achieved 74 percent in the blue end. Detailed modeling of the data indicates that a high front surface recombination velocity is responsible for the low blue response, that the carrier lifetime is high enough to allow good carrier collection from both the base and the emitter, and that the voltage is base-limited.

Keavney, Christopher; Spitzer, Mark B.; Vernon, Stanley M.; Haven, Victor E.; Augustine, Godfrey

1989-01-01

214

Si Microwire Array Solar Cells  

SciTech Connect

Si microwire-array solar cells with Air Mass 1.5 Global conversion efficiencies of up to 7.9% have been fabricated using an active volume of Si equivalent to a 4 ?m thick Si wafer. These solar cells exhibited open-circuit voltages of 500 mV, short-circuit current densities (J{sub sc}) of up to 24 mA cm{sup -2}, and fill factors >65% and employed Al{sub 2}O{sub 3} dielectric particles that scattered light incident in the space between the wires, a Ag back reflector that prevented the escape of incident illumination from the back surface of the solar cell, and an a-SiN{sub x}:H passivation/anti-reflection layer. Wire-array solar cells without some or all of these design features were also fabricated to demonstrate the importance of the light-trapping elements in achieving a high J{sub sc}. Scanning photocurrent microscopy images of the microwire-array solar cells revealed that the higher J{sub sc} of the most advanced cell design resulted from an increased absorption of light incident in the space between the wires. Spectral response measurements further revealed that solar cells with light-trapping elements exhibited improved red and infrared response, as compared to solar cells without light-trapping elements.

Putnam, Morgan C.; Boettcher, Shannon W.; Kelzenberg, Michael D.; Turner-Evans, Daniel B.; Spurgeon, Joshua M.; Warren, Emily L.; Briggs, Ryan M.; Lewis, Nathan S.; Atwater, Harry A.

2010-01-01

215

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

216

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

217

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

218

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

219

Module level solutions to solar cell polarization  

SciTech Connect

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

220

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

221

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

222

Zinc  

MedlinePLUS

... as most children in the United States. The common cold Some studies suggest that zinc lozenges or syrup ( ... in pill form) help speed recovery from the common cold and reduce its symptoms if taken within 24 ...

223

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

224

High intensity solar cell radiometer  

NASA Technical Reports Server (NTRS)

Device can be employed under high intensity illumination conditions such as would occur in a close-solar-approach space mission or in monitoring high intensity lamps. Radiometer consists of silicon solar cells with thin semi-transparent coatings of aluminum deposited on the front surfaces to permit transmission of small percentage of light and reflect the remainder.

Brandhorst, H. W.; Spisz, E. W.

1972-01-01

225

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

E-print Network

Solar Energy Materials & Solar Cells 91 (2007) 1599­1610 Improving solar cell efficiency using efficiency of solar cell devices without using concentrators. r 2007 Elsevier B.V. All rights reserved) solar energy conversion systems (or solar cells) are the most widely used power systems. However

Dowling, Jonathan P.

226

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

227

Managing aluminum phosphide poisonings  

PubMed Central

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 KMnO4, 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

2011-01-01

228

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

229

24% efficient silicon solar cells  

Microsoft Academic Search

This paper reports significant progress in silicon solar cell performance, taking confirmed efficiency beyond 24% for the first time. This progress has been achieved by a combination of several mechanisms. One is the reduction of recombination at the cell front surface by improved passivation of the silicon\\/silicon dioxide interface. Resistive losses in the cell have been reduced by a double-plating

Jianhua Zhao; Aihua Wang; Pietro P. Altermatt; Stuart R. Wenham; Marltin A. Green

1994-01-01

230

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

231

EE580 Solar Cells Todd J. Kaiser  

E-print Network

7/21/2010 1 EE580 ­ Solar Cells Todd J. Kaiser · Lecture 10 · Summary 1Montana State University: Solar Cells Lecture 10: Summary Summer 2010 Class Montana State University: Solar Cells Lecture 10: Summary 2 Solar Cell Operation n Emitter p Base Rear Contact Antireflection coating Absorption of photon

Kaiser, Todd J.

232

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

233

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

234

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

235

Optimization of transparent and reflecting electrodes for amorphous-silicon solar cells  

NASA Astrophysics Data System (ADS)

Fluorine-doped zinc oxide was shown to have the lowest absorption loss of any of the known transparent conductors. An apparatus was constructed to deposit textured, transparent, conductive, fluorine-doped zinc oxide layers with uniform thickness over a 10 cm by 10 cm area, using inexpensive, high-productivity atmospheric pressure chemical vapor deposition. Amorphous silicon solar cells grown on these textured films show very high peak quantum efficiencies (over 90 percent). However, a significant contact resistance develops at the interface between the amorphous silicon and the zinc oxide. Transparent, conductive gallium-doped zinc oxide films were grown by APCVD at a low enough temperature (260 C) to be deposited on amorphous silicon as a final conductive back contact to solar cells. A quantum-mechanical theory of bonding was developed and applied to some metal oxides; it forms a basis for understanding TCO structures and the stability of their interfaces with silicon.

Gordon, R. G.; Hu, J.; Lacks, D.; Musher, J.; Thornton, J.; Liang, H.

1994-07-01

236

Fundamental studies of the metallurgical, electrical, and optical properties of gallium phosphide and gallium phosphide alloys  

NASA Technical Reports Server (NTRS)

Abstracts, bibliographic data, oral presentations, and published papers on (1) Diffusion of Sulfur in Gallium Phosphide and Gallium Arsenide, and (2) Properties of Gallium Phosphide Schottky Barrier Rectifiers for Use at High Temperature are presented.

1972-01-01

237

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

238

Role of metallothionein in the zinc metabolism of Ehrlich ascites tumor cells  

SciTech Connect

The reactions of zinc and zinc, cadmium metallothioneins with apocarbonic anhydrase have been studied. Apo-carbonic anhydrase abstracts zinc from zinc metallothionein and zinc, cadmium metallothionein in second-order processes which are two to three orders of magnitude more rapid than those of EDTA abstraction of zinc and are similar to the rate of reconstitution of the apo-enzyme by unligated Zn. In comparison with other proteins, zinc metallothionein contains unusually reactive metal binding sites suggesting this protein may be a physiological donor of Zn to zinc requiring sites in cells. When limiting amounts of dietary zinc stimulate the deficient cells to divide, zinc is not observed in metallothionein. A non-limiting amount of dietary zinc supports both proliferation and the steady state presence of zinc in this protein. Zinc metallothionein is shown to be the principal donor of zinc to added apo-carbonic anhydrase in Ehrlich cell cytosol. Treatment of cells with a copper ligand known to possess anti-tumor activity, with the toxic metal Cd, or with cis-dichlorodiamine Pt(II) which is another anti-tumor agent, all cause cells to cease proliferation at levels of each agent which result in the displacement of zinc from metallothionein. These results are used to construct a model of zinc metabolism in which Zn metallothionein is a central, biochemically active form of zinc. The finding in a number of tumors other than Ehrlich ascites carcinoma of the existence of metal binding protein with characteristics similar to metallothionein suggests that the significantly elevated levels of metallothionein-like protein may be a general feature of many tumors and that it may play a vital role in rapidly proliferating tissue in general.

Kraker, A.J.

1983-01-01

239

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

240

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

241

Spectral reflectance properties of electroplated and converted zinc for use as a solar selective coating  

NASA Technical Reports Server (NTRS)

The spectral reflectance properties of electroplated and chemically converted zinc were measured for both chromate and chloride conversion coatings. The reflectance properties were measured for various times of conversion and for conversion at various chromate concentrations. The values of absorptance, integrated over the solar spectrum, and of infrared emittance, integrated over black body radiation at 250 F were then calculated from the measured reflectance values. The interdependent variations of absorptance and infrared emittance were plotted. The results indicate that the optimum combination of the highest absorptance in the solar spectrum and the lowest emittance in the infrared of the converted electroplated zinc is produced by chromate conversion at 1/2 concentration of the standard NEOSTAR chromate black solution for 0.50 minute or by chloride conversion for 0.50 minute.

Mcdonald, G. E.; Curtis, H. B.; Gianelos, L.

1975-01-01

242

Recent Developments in Silver/Zinc Rechargeable Cell Studies  

NASA Technical Reports Server (NTRS)

This viewgraph presentation discusses silver/zinc cell casing configurations and test results examining discharge capacity and silver migration comparisons. The following recommendations were proposed: 1) Use silver-treated cellophane instead of clear cellophane; 2) Use split wrap for cellophane whenever possible; and 3) Strongly consider use of sausage casing with PVA film in the following configuration: 1-mil (tubular) SC/1-mil PVA film/2.3-mil plain or 6-mil fiber-reinforced SC tubular.

Lewis, Harlan L.

2001-01-01

243

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

244

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

245

Dietary Zinc Deficiency in Rodents: Effects on T-Cell Development, Maturation and Phenotypes  

PubMed Central

Zinc deficiency is one of the leading risk factors for developing disease and yet we do not have a clear understanding of the mechanisms behind the increased susceptibility to infection. This review will examine the interrelationships among the hypothalamus-pituitary-adrenal stress axis, p56lck, and T-cell maturation in both zinc deficiency and responses during zinc repletion. We will highlight differences between the adult mouse model (wasting malnutrition) and growing rat model (stunting malnutrition) of dietary zinc deficiency and discuss the use of various controls to separate out the effects of zinc deficiency from the associated malnutrition. Elevated serum corticosterone in both zinc deficient and pair-fed rats does not support the hypothesis that zinc deficiency per se leads to corticosterone-induced apoptosis and lymphopenia. In fact, the zinc deficient rat does not have lymphopenia. Thymocytes from zinc deficient mice and rats have elevated levels of p56lck, a signalling protein with a zinc clasp structure, but this does not appear to affect thymocyte maturation. However, post-thymic T-cell maturation appears to be altered based on the lower proportion of splenic late thymic emigrants in zinc deficient rats. Fewer new T-cells in the periphery could adversely affect the T-cell repertoire and contribute to immunodeficiency in zinc deficiency. PMID:22822446

Blewett, Heather J.; Taylor, Carla G.

2012-01-01

246

Performance of silicon solar cells under concentration  

Microsoft Academic Search

Generally solar cells have been designed and fabricated to work with unit solar flux. A cell optimized for such conditions definitely is not best for use under concentration. A theoretical model of a Si solar cell was developed to help with this optimization and then compared to experimental measurements made on commercial state-of-the-art cells at concentrations between 1 and 10

R. O. Bell; J. C. T. Ho; W. T. Kurth

1976-01-01

247

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

248

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

249

Impedance of silver oxide-zinc cells  

NASA Technical Reports Server (NTRS)

Over 100 sealed AgO-Zn cells were subjected to prolonged periods of storage over a range of temperatures and storage modes including open circuit, trickle charge, and float charge. Impedances of these cells were monitored throughout, and at the end of the storage period their transient voltage characteristics were observed at the onset of discharge. Results revealed that the impedances of these cells tended to increase with storage time; the magnitude of the impedance rise was dependent primarily on temperature and to a lesser degree on storage mode. Typical values for 50 A-hr cells were usually less than 100 mohm immediately after activation and from 1 to 30 ohm after 6-10 months of storage. Transient voltages of these cells droped sharply during the first msec of discharge and then rose to a stablized value during the following few seconds. The magnitude of the initial drop and the stabilized voltage values were found to be related to impedance but not in a linear manner. The magnitude and duration of the low transient voltages may be unacceptable in some applications of these cells. The impedance variations are attributed to changes occurring at the positive electrode.

Frank, H. A.; Long, W. L.; Uchiyama, A. A.

1976-01-01

250

The molecular beam epitaxy growth and characterization of zinc cadmium selenide/zinc cadmium magnesium selenide-indium phosphide quantum cascade structures for operation in the 3 - 5 um range  

NASA Astrophysics Data System (ADS)

The quantum cascade (QC) laser has captured the interest of researchers for almost three decades. In the early stages, researchers were very interested in proving the QC concept1 proposed by Kazarinov and Suris in 1971. This new concept gave researchers hope that very bulky energy inefficient infra-red (IR) lasers would be replaced with ones that are very compact, tunable and portable. Since the proposal of the QC laser concept and its first demonstration by researchers at Bell Laboratories2 in 1994, this technology has progressed to the point where it is now finding commercial applications in a variety of areas such as military counter measures, free space telecommunications, infra-red imaging and chemical spectroscopy.3-5 The success of this technology can be attributed to the coming of age of the techniques of molecular beam epitaxy (MBE) semiconductor growth and bandgap engineering. 6,7 Using MBE technology, the temperature of the source material can be stabilized by making use of a combination of proportional integral derivative (PID) controllers and thermocouple feedbacks. As a result, the material flux from the effusion cells can achieve stability better than (+/-) 1%. This flux stability together with a well-developed computer controlled shuttering mechanism make it possible to grow multi-quantum well (MQW) structures with excellent layer thickness precision (mono-layer scale) and interface quality. This stringent control of material flux is also a tool that is used by MBE growers to vary the material compositions for the growth of lattice matched and strain compensated QC structures. Today, MBE stands out as one of the premier methods for growing high performing QC lasers. The first successful demonstration of a QC laser2 was done using the InGaAs/InAlAs-InP material system. This demonstration was then repeated a few years later using GaAs/AlGaAs-InP.8 These III-V material systems were extensively studied to establish their material parameters. Given that material parameters are critically important in the process of modeling QC structures, it is not surprising that early success was achieved using these systems. Today, the best performing QC lasers operate in the 4--13 mum range and are produced using lattice matched InGaAs/InAlAs-InP. In order to produce short wavelength QC lasers, the well layer thicknesses in the active region of the device must be reduced in an effort to push the lasing energy states further apart. This reduction in well thicknesses results in the movement of the upper lasing state closer to the bandedge. This action increases the probability of the lost of lasing state electrons to the continuum. Therefore, in order to produce high performing short wavelength QC lasers, a large conduction band offset (CBO) is required. The CBO of lattice matched InGaAs/InAlAs-InP is 0.52 eV. In an attempt to produce high performing devices below 4 mum many researchers have resorted to the use of strain compensation9-11 . This approach has yielded very little improvement in performance due to electron scattering to the X and L intervalleys. This has lead to the exploration of wide bandgap material systems such as the antominides and nitrides. In this work the wide bandgap II-V Znx'Cd(1-x')Se/Zn xCdyMg(1-x-y)Se-InP will be explored for QC laser fabrication. To this end, QC lasers were designed for operation at 3--5 mum range. A Matlab-based program was written to calculate the energy level spacing within the active region of these devices. This simulation program was based on Schroindger's equation and the transfer matrix technique. Several calibration samples were grown to establish the doping levels and growth rate of the well and barrier materials. The growth rate was measured using scanning electron microscopy (SEM) and reflection high energy electron diffraction (RHEED) oscillations during MBE growth. X-ray diffraction measurements were performed to determine the lattice mismatch of the II-VI bulk layers, and therefore predict whether material composition adjustments were required to attain the lattice

Charles, William O.

251

Compensated amorphous silicon solar cell  

DOEpatents

An amorphous silicon solar cell incorporates a region of intrinsic hydrogenated amorphous silicon fabricated by a glow discharge wherein said intrinsic region is compensated by P-type dopants in an amount sufficient to reduce the space charge density of said region under illumination to about zero.

Carlson, David E. (Yardley, PA)

1980-01-01

252

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

253

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.

254

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.

255

Very High Efficiency Solar Cell Modules  

Microsoft Academic Search

The Very High Efficiency Solar Cell (VHESC) program is developing integrated optical system - PV modules for portable applications that operate at greater than 50% efficiency. We are integrating the optical design with the solar cell design, and have entered previously unoccupied design space. Our approach is driven by proven quantitative models for the solar cell design, the optical design,

Allen Barnett; Douglas Kirkpatrick; Christiana Honsberg; Duncan Moore; Mark Wanlass; Keith Emery; Richard Schwartz; Dave Carlson; Stuart Bowden; Dan Aiken; Allen Gray; Sarah Kurtz; Larry Kazmerski; Myles Steiner; Jeffery Gray; Tom Davenport; Roger Buelow; Laszlo Takacs; Narkis Shatz; John Bortz; Omkar Jani; Keith Goossen; Fouad Kiamilev; Alan Doolittle; Ian Ferguson; Blair Unger; Greg Schmidt; Eric Christensen; David Salzman

2009-01-01

256

MILESTONES TOWARD 50% EFFICIENT SOLAR CELL MODULES  

Microsoft Academic Search

The Very High Efficiency Solar Cell (VHESC) program is developing integrated optical system - PV modules for portable applications that operate at greater than 50 percent efficiency. We are integrating the optical design with the solar cell design, and have entered previously unoccupied design space. Our approach is driven by proven quantitative models for the solar cell design, the optical

Allen Barnett; Douglas Kirkpatrick; Christiana Honsberg; Duncan Moore; Mark Wanlass; Keith Emery; Richard Schwartz; Dave Carlson; Stuart Bowden; Dan Aiken; Allen Gray; Sarah Kurtz; Larry Kazmerski; Tom Moriarty; Myles Steiner; Jeffery Gray; Tom Davenport; Roger Buelow; Laszlo Takacs; John Bortz; Omkar Jani; Keith Goossen; Fouad Kiamilev; Alan Doolittle; Ian Ferguson; Blair Unger; Greg Schmidt

257

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 Several types of operating modes · Centralized power plant or wanted Montana State University: Solar Cells Lecture 9: PV Systems 2 Residential Side Mounted Montana

Kaiser, Todd J.

258

Optical materials technology for energy efficiency and solar energy conversion IX; Proceedings of the European Congress on Optics, The Hague, Netherlands, Mar. 12, 13, 1990  

Microsoft Academic Search

Various paper on optical materials technology for energy efficiency and solar energy conversion are presented. Individual topics addressed include: ultrathin lamellar gratings as solar-selective coatings, optical properties of SnO(x) thin films, properties of dc-magnetron-sputtered NiSiO(x) films, solar control coating of Fabry-Perot type for energy efficiency glass, thin film preparation of semiconducting iron pyrite, simulation of the indium-phosphide-based solar cell, characterization

Cales G. Grandqvist; Carl M. Lampert

1990-01-01

259

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

260

Cascade Solar Cell Workshop report  

NASA Technical Reports Server (NTRS)

Issues related to the feasibility, research and development, and demonstration of a 30% AMO cascade solar cell discussed include the material selection, growth and fabrication techniques, and device development strategy for a monolithic (two terminal) cascade cell, a hybrid (four terminal) cascade cell, and a spectral splitting device (three cells). Workshop recommendations include: (1) initiate a long range research program to develop a three junction, monolithic, cascade cell using either AlGaAsSb-GaAsSb or AlGaInAs-GaInAs material system; (2) emphasize OM-CVD epitaxial growth technique, perhaps combined with other technologies in the near term to obtain tunnel junctions; (3) develop a two junction device first; (4) initiate a cascade solar cell modeling program to study and compare performance of two and four terminal cascade devices exposed to electron and proton irradiation; and (5) encourage and be open to new ideas for developing four terminal, hybrid, cascade cells exploiting novel component cell interconnect technologies.

Hutchby, J. A.

1980-01-01

261

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

262

Automated solar-cell-array assembly machine  

NASA Technical Reports Server (NTRS)

Continuous-feeding machine automatically bonds solar cells to printed-circuit substrate. In completed machine, cells move to test station where electrical characteristics could be checked. If performance of cell is below specifications, that cell is marked and removed. All machine functions are synchronized by electronics located within unit. It may help to lower costs in future solar-cell production.

Costogue, E. N.; Mueller, R. L.; Person, J. K.; Yasui, R. K.

1978-01-01

263

ITO/InP solar cells: A comparison of devices fabricated by ion beam and RF sputtering of the ITO  

NASA Technical Reports Server (NTRS)

This work was performed with the view of elucidating the behavior of indium tin oxide/indium phosphide (ITO/InP) solar cells prepared by RF and ion beam sputtering. It was found that using RF sputter deposition of the ITO always leads to more efficient devices than ion beam sputter deposition. An important aspect of the former technique is the exposure of the single crystal p-InP substrates to a very low plasma power prior to deposition. Substrates treated in this manner have also been used for ion beam deposition of ITO. In this case the cells behave very similarly to the RF deposited cells, thus suggesting that the lower power plasma exposure (LPPE) is the crucial process step.

Coutts, T. J.

1987-01-01

264

Mixed ternary heterojunction solar cell  

DOEpatents

A thin film heterojunction solar cell and a method of making it has a p-type layer of mixed ternary I-III-VI.sub.2 semiconductor material in contact with an n-type layer of mixed binary II-VI semiconductor material. The p-type semiconductor material includes a low resistivity copper-rich region adjacent the back metal contact of the cell and a composition gradient providing a minority carrier mirror that improves the photovoltaic performance of the cell. The p-type semiconductor material preferably is CuInGaSe.sub.2 or CuIn(SSe).sub.2.

Chen, Wen S. (Seattle, WA); Stewart, John M. (Seattle, WA)

1992-08-25

265

Point contact silicon solar cells  

NASA Technical Reports Server (NTRS)

The construction of a 22.2% efficient single-crystal silicon solar cell fabricated at Stanford University is described. The cell dimensions were 3 x 5 mm and 100 microns thick with a base lifetime of 500 microseconds. The cell featured light trapping between a texturized top surface and a reflective bottom surface, small point contact diffusions, alternating between n-type and p-type in a polka-dot pattern on the bottom surface, and a surface passivation on all surfaces between contact regions.

Swanson, R. M.

1986-01-01

266

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

267

Biological solar cell  

SciTech Connect

Recent reports have demonstrated the possibility of employing photoactive, biological membrane components in photoelectrochemical cells. Present studies in our laboratories have led to the attachment of a much simpler biological complex, the bacterial photosynthetic reaction center isolated from Rhodopseudomonas sphaeroides, directly onto a SnO/sub 2/ semiconductor electrode. Light-induced photovoltages (70mV) and photocurrents (0.5 ..mu..A/cm/sup 2/) not attributable to Dember effects have been observed in photoelectrochemical cells employing reaction-center-coated, SnO/sub 2/ working electrodes. Such reaction-center electrodes may serve as model systems for future organic photovoltaic devices.

Seibert, M.; Janzen, A.F.

1980-04-01

268

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

269

Transparent conducting oxides (TCO's) for amorphous silicon solar cells  

NASA Astrophysics Data System (ADS)

The stability of various textured tin oxide and zinc oxide transparent conductors was evaluated against annealing in air, in vacuum or exposed to hydrogen plasma. Only fluorine-doped zinc oxide deposited by atmospheric pressure chemical vapor deposition (APCVD) had stable electrical and optical properties under all conditions. Thin layers of ZnO or TiO2 greatly improved the plasma resistance of SnO2. A new TCO material, niobium-doped titanium dioxide (TiO2:Nb) was able to withstand hydrogen plasmas with only slight increases in its optical absorption and conductivity. Composite TCO's consisting of glass/SnO2:F/TiO2:Nb were shown to provide good electrical contact to amorphous silicon solar cells.

Hegedus, Steven; Liang, Haifan; Gordon, Roy G.

1996-01-01

270

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

271

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

272

Study of solar cell welds  

NASA Technical Reports Server (NTRS)

The thermal imaging technique was evaluated for its capabilities in the nondestructive evaluation of solar cell welds. The temperature and spatial resolution of state of the art instrumentation was sufficient for both qualitative and quantitative determination of the quality of solar cell welds. The addition of color digitized thermography enhanced the aspects of the thermographic display and allowed easily computerized testing procedures. For automated testing systems an accurate correlation of weld quality with temperature profiles of the welds needs to be performed. In comparison, the holographic technique was complementary with the thermal imaging technique, except that the holographic analysis appeared to be more quantitative at the present time. However, the thermal imaging approach is much more versatile in overall capabilities.

Workman, G. L.

1978-01-01

273

Compensated amorphous silicon solar cell  

DOEpatents

An amorphous silicon solar cell including an electrically conductive substrate, a layer of glow discharge deposited hydrogenated amorphous silicon over said substrate and having regions of differing conductivity with at least one region of intrinsic hydrogenated amorphous silicon. The layer of hydrogenated amorphous silicon has opposed first and second major surfaces where the first major surface contacts the electrically conductive substrate and an electrode for electrically contacting the second major surface. The intrinsic hydrogenated amorphous silicon region is deposited in a glow discharge with an atmosphere which includes not less than about 0.02 atom percent mono-atomic boron. An improved N.I.P. solar cell is disclosed using a BF.sub.3 doped intrinsic layer.

Devaud, Genevieve (629 S. Humphrey Ave., Oak Park, IL 60304)

1983-01-01

274

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.

2014-06-03

275

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

276

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

277

Nanosized Zinc Oxide Induces Toxicity in Human Lung Cells  

PubMed Central

Zinc oxide nanoparticles (ZnO-NPs) are increasingly used in sunscreens, biosensors, food additives, pigments, rubber manufacture, and electronic materials. With the wide application of ZnO-NPs, concern has been raised about its unintentional health and environmental impacts. This study investigates the toxic effects of ZnO-NPs in human lung cells. In order to assess toxicity, human lung epithelial cells (L-132) were exposed to dispersion of 50?nm ZnO-NPs at concentrations of 5, 25, 50, and 100??g/mL for 24?h. The toxicity was evaluated by observing changes in cell morphology, cell viability, oxidative stress parameters, DNA damage analysis, and gene expression. Exposure to 50?nm ZnO-NPs at concentrations between 5 and 100??g/mL decreased cell viability in a concentration-dependent manner. Morphological examination revealed cell shrinkage, nuclear condensation, and formation of apoptotic bodies. The oxidative stress parameters revealed significant depletion of GSH level and increase in ROS levels suggesting generation of oxidative stress. ZnO-NPs exposure caused DNA fragmentation demonstrating apoptotic type of cell death. ZnO-NPs increased the expression of metallothionein gene, which is considered as a biomarker in metal-induced toxicity. To summarize, ZnO-NPs cause toxicity in human lung cells possibly through oxidative stress-induced apoptosis. PMID:23997968

Sahu, Devashri; Kannan, G. M.; Vijayaraghavan, R.; Anand, T.; Khanum, Farhath

2013-01-01

278

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

279

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

280

Silicon Carbide Solar Cells Investigated  

NASA Technical Reports Server (NTRS)

The semiconductor silicon carbide (SiC) has long been known for its outstanding resistance to harsh environments (e.g., thermal stability, radiation resistance, and dielectric strength). However, the ability to produce device-quality material is severely limited by the inherent crystalline defects associated with this material and their associated electronic effects. Much progress has been made recently in the understanding and control of these defects and in the improved processing of this material. Because of this work, it may be possible to produce SiC-based solar cells for environments with high temperatures, light intensities, and radiation, such as those experienced by solar probes. Electronics and sensors based on SiC can operate in hostile environments where conventional silicon-based electronics (limited to 350 C) cannot function. Development of this material will enable large performance enhancements and size reductions for a wide variety of systems--such as high-frequency devices, high-power devices, microwave switching devices, and high-temperature electronics. These applications would supply more energy-efficient public electric power distribution and electric vehicles, more powerful microwave electronics for radar and communications, and better sensors and controls for cleaner-burning, more fuel-efficient jet aircraft and automobile engines. The 6H-SiC polytype is a promising wide-bandgap (Eg = 3.0 eV) semiconductor for photovoltaic applications in harsh solar environments that involve high-temperature and high-radiation conditions. The advantages of this material for this application lie in its extremely large breakdown field strength, high thermal conductivity, good electron saturation drift velocity, and stable electrical performance at temperatures as high as 600 C. This behavior makes it an attractive photovoltaic solar cell material for devices that can operate within three solar radii of the Sun.

Bailey, Sheila G.; Raffaelle, Ryne P.

2001-01-01

281

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

282

Solar cell preparation in thin silicon membranes  

Microsoft Academic Search

Solar cells prepared in a thin (≈30 ?m) crystalline silicon membrane with a supporting frame allow an evaluation of the potential of c-Si thin film cells on cheap substrates. At the same time, lightweight and more radiation-hard solar cells may have direct applications in space. This paper studies the fabrication process of solar cells in ≈30 ?m thick p-Si epitaxial

M. Libezny; J. Poortmans; M. Caymax; G. Beaucame; W. Laureys; J. Nijs

1997-01-01

283

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

284

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

285

Toxicology and carcinogenesis studies of indium phosphide (CAS No. 22398-90-7) in F344/N rats and B6C3F1 mice (inhalation studies).  

PubMed

Indium phosphide is used to make semiconductors,injection lasers, solar cells, photodiodes, and light-emittingdiodes. Indium phosphide was nominated for study because of its widespread use in the microelectronics industry, the potential for worker exposure,and the absence of chronic toxicity data. Male and female F344/N rats and B6C3F1 mice were exposed to indium phosphide (greater than 99% pure) by inhalation for 14 weeks or 2 years. The frequency of micronuclei was determined in the peripheral blood of mice exposed to indium phosphide for 14 weeks. 14-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were exposed to particulate aerosols of indium phosphide with amass median aerodynamic diameter of approximately 1.2 microm at concentrations of 0, 1, 3, 10, 30, or 100 mg/m3 by inhalation, 6 hours per day, 5 days per week (weeks 1 through 4 and weeks 10 through 14) or 7 days per week (weeks 5 through 9) to accommodate a concurrent teratology study. One male in the 100 mg/m3 group died before the end of the study. Body weight gains of all males and females exposed to 100 mg/m3 were less than those of the chamber controls. As a result of indium phosphide exposure, the lungs of all exposed rats had a gray to black discoloration and were significantly enlarged, weighing 2.7- to 4.4-fold more than those of the chamber controls. Indium phosphide particles were observed throughout the respiratory tract and in the lung-associated lymph nodes. A spectrum of inflammatory and proliferative lesions generally occurred in the lungs of all exposed groups of rats and consisted of alveolar proteinosis, chronic inflammation, interstitial fibrosis, and alveolar epithelial hyperplasia. Pulmonary inflammation was attended by increased leukocyte and neutrophil counts in the blood. The alveolar proteinosis was the principal apparent reason for the increase in lung weights. Indium phosphide caused inflammation at the base of the epiglottis of the larynx and hyperplasia of the bronchial and mediastinal lymph nodes. Exposure to indium phosphide affected the circulating erythroid mass. It induced a microcytic erythrocytosis consistent with bone marrow hyperplasia and hematopoietic cell proliferation of the spleen. Hepatocellular necrosis was suggested by increased serum activities of alanine aminotransferase and sorbitol dehydrogenase in all exposed groups of males and in 10 mg/m3 or greater females and was confirmed microscopically in 100 mg/m3 males and females. 14-WEEK STUDY IN MICE: Groups of 10 male and 10 female mice were exposed to particulate aerosols of indium phosphide with a mass median aerodynamic diameter of approximately 1.2 microm at concentrations of 0, 1, 3, 10, 30, or 100 mg/m3 by inhalation, 6 hours per day, 5 days per week (weeks 1 through 4 and weeks 10 through 14)or 7 days per week (weeks 5 through 9). Although the effects of indium phosphide exposure were similar in rats and mice, mice were more severely affected in that all males and females in the 100 mg/m3 groups either died or were removed moribund during the study. One male and three females in the 30 mg/m3 group were also removed before the end of the study. In general, body weight gains were significantly less in males and females exposed to 3 mg/m3 or greater compared to those of the chamber controls. Mice exposed to 30 or 100 mg/m3 were lethargic and experienced rapid, shallow breathing. As in rats, lungs were discolored and enlarged 2.6- to 4.1-fold greater than those of chamber controls due to the exposure-induced alveolar proteinosis. Indium phosphide particles were observed in the nose, trachea,larynx, and lymph nodes of some exposed males and females. Alveolar proteinosis, chronic active inflammation,interstitial fibrosis, and alveolar epithelial hyperplasia were observed; these effects were more severe than in rats. Hyperplasia in the bronchial lymph nodes and squamous metaplasia, necrosis, and suppurative inflammation of the larynx were observed in some exposed males and females. Exposure to indium phosphide induced a microcytic erythrocytosis which was

2001-07-01

286

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;...

287

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

288

Integrally covered silicon solar cells.  

NASA Technical Reports Server (NTRS)

The electron-beam technique for evaporating dielectric materials onto solar cells has been examined and developed. Titanium oxide cell antireflection coatings have been obtained which compare to silicon monoxide in environmental capabilities and which provide 3 to 4% improvement over SiO for glass covered cells. Evaporation processes have been obtained which provide a 50 to 100 micromil thick transparent (0.5 to 1.0% absorption per mil), low stressed integral cover capable of surviving space type qualification testing. Irradiation with 10 to the 15th power 1-MeV electrons shows 2% darkening, and long term UV irradiation incurs approximately 1.3% cover darkening for 50 micromil thick covers.

Stella, P. M.; Somberg, H.

1972-01-01

289

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

290

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

291

New experimental techniques for solar cells  

NASA Technical Reports Server (NTRS)

Solar cell capacitance has special importance for an array controlled by shunting. Experimental measurements of solar cell capacitance in the past have shown disagreements of orders of magnitude. Correct measurement technique depends on maintaining the excitation voltage less than the thermal voltage. Two different experimental methods are shown to match theory well, and two effective capacitances are defined for quantifying the effect of the solar cell capacitance on the shunting system.

Lenk, R.

1993-01-01

292

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

293

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

294

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

295

Very High Efficiency Solar Cell Modules  

SciTech Connect

The Very High Efficiency Solar Cell (VHESC) program is developing integrated optical system - PV modules for portable applications that operate at greater than 50% efficiency. We are integrating the optical design with the solar cell design, and have entered previously unoccupied design space. Our approach is driven by proven quantitative models for the solar cell design, the optical design, and the integration of these designs. Optical systems efficiency with an optical efficiency of 93% and solar cell device results under ideal dichroic splitting optics summing to 42.7 {+-} 2.5% are described.

Barnett, A.; Kirkpatrick, D.; Honsberg, C.; Moore, D.; Wanlass, M.; Emery, K.; Schwartz, R.; Carlson, D.; Bowden, S.; Aiken, D.; Gray, A.; Kurtz, S.; Kazmerski, L., et al

2009-01-01

296

Sources of high photo-current in inverted organic solar cells  

NASA Astrophysics Data System (ADS)

Inverted organic solar cells have been proved to render exceptional environmental stability compared to the conventional solar cell architecture. On the other hand, polymer/fullerene based inverted solar cells produce more photo-current compared to conventional cells comprising the same active layer thickness. The origin of this current has never been clearly stated so far. We have investigated the photovoltaic properties of inverted solar cells comprising a bulk heterojunction layer of poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM). The blend layer was formed by spin casting the blend solution on ITO substrate, covered with an Al doped zinc-oxide layer (ZnO-Al) deposited through pulsed laser deposition technique. The inverted solar cells show over 15% increase in photo-current yield compared to conventional solar cells. We have discovered that the inverted solar cells produce additional photo-current through dissociation of excited electron-hole pairs near the polymer/ZnO-Al interfaces. Since ZnO-Al is a good electron conductor, the electrons generated at the polymer/ZnO-Al interface are more efficiently collected compared to photo-current produced in the bulk of the active film. External quantum efficiency exceeding 70% was recorded in the ZnO-Al based inverted solar cells. In general, ZnO-Al is not only characterized by its high electron conductivity, and transparency but also serves as electron acceptor.

Gadisa, Abay; Liu, Yingchi; Lopez, Rene; Samulski, Edward

2012-02-01

297

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

298

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

299

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

300

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

301

Detailed balance theory of excitonic and bulk heterojunction solar cells  

Microsoft Academic Search

A generalized solar cell model for excitonic and classical bipolar solar cells describes the combined transport and interaction of electrons, holes, and excitons in accordance with the principle of detailed balance. Conventional inorganic solar cells, single-phase organic solar cells and bulk heterojunction solar cells, i.e., nanoscale mixtures of two organic materials, are special cases of this model. For high mobilities,

Thomas Kirchartz; Julian Mattheis; Uwe Rau

2008-01-01

302

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

303

OSMIUM ZINC IODIDE REACTIVE SITES IN THE EPIDERMAL LANGERHANS CELL  

PubMed Central

Fixation of epidermis with a mixture of osmium tetroxide and zinc iodide (OsO4-ZnI2) for 24 hr renders the central periodic lamella of the Langerhans cell granule (LCG), the Golgi region, and the nuclear envelope of epidermal Langerhans cells preferentially visible. The use of this technique on Langerhans cells in normal epidermis and in epidermis of patients with histiocytosis (Letterer-Siwe disease) allows a broader visualization of the LCG's than was heretofore possible with routine glutaraldehyde-osmium tetroxide fixation and uranyl acetate-lead staining. The identical staining of Golgi apparatus and LCG favors the view that there is close relation between the Golgi area and the LCG's. Different staining characteristics of the LCG's near the Golgi region and at the cell periphery, respectively, may suggest that the LCG undergoes changes on its way from the Golgi area towards the extracellular space. The hypothesis is advanced that the material which is heavily impregnated with metal after fixation with OsO4-ZnI2 might be a lipid. PMID:4186413

Niebauer, Gustav; Krawczyk, Walter S.; Kidd, Richard L.; Wilgram, George F.

1969-01-01

304

Life testing of secondary silver-zinc cells  

NASA Technical Reports Server (NTRS)

Testing on a variety of secondary silver-zinc (Ag-Zn) cells has been in progress at the Marshall Space Flight Center (MSFC) for over six years. The latest test involves a 350-Ah cell design that has been cycled at 10 C for 16 months. This design has achieved over 7200 low-earth-orbit (LEO) cycles as well as 17 deep discharges at an 85 percent depth of discharge. This test not only is a life test on these cells but also addresses different methods of storing these cells between the deep discharges. As the test is approaching completion, some interesting results are being seen. In particular, two of the four packs currently on test have failed to meet the 35-h (295-Ah) deep discharge requirement that was arbitrarily set at the beginning of the test. This capacity loss failure is likely a result of the storage method used on these two packs between deep discharges. The two packs are LEO cycled in such a way as to minimize overcharge in an attempt to prolong life.

Brewer, Jeffrey C.; Doreswamy, Rajiv

1991-01-01

305

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

306

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

307

Preparation of heterojunction solar cell  

NASA Astrophysics Data System (ADS)

Heterojunction solar cells of SnO 2: P/ n-Si (textured), having AM1 efficiency of 11.0% on single silicon crystal, have been fabricated. The phosphorosu doped tin oxide films are deposited by chemical vapour deposition technique on a heated silicon substrate having a resistivity of 0.1 ? cm. Before the deposition of SnO 2: P, the wafers are textured and growth of a SiO 2 layer on the Si surface was avoided. The C- V measurement at 1 kHz frequency shows the abrupt nature of the junction with a built-in voltage Vd = 0.62 V. The variation of cell parameters with temperature has also been studied.

Vishwakarma, S. R.; Rahmatullah; Prasad, H. C.

1993-09-01

308

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

309

Zinc Enhances Ionic Currents Induced in Skate Muller (Glial) Cells by the Inhibitory Neurotransmitter GABA  

Microsoft Academic Search

We describe here a novel effect of zinc on GABA receptors of glial cells in the skate retina. The GABA-induced currents of skate Muller cells, the radial glia of the retina, are mediated by activation of GABAA receptors (GABAARs). In other parts of the nervous system, GABAA-mediated currents are inhibited by zinc. However, in isolated, voltage-clamped Muller cells, coapplication of

Haohua Qian; Robert Paul Malchow; Richard L. Chappell; Harris Ripps

1996-01-01

310

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

311

Towards efficient tin-doped indium oxide (ITO)-free inverted organic solar cells using metal cathodes  

Microsoft Academic Search

We present zinc phthalocyanine (ZnPc):C60 bulk-heterojunction top-illuminated organic solar cells using ultrathin metal layers as transparent top contacts. We show that solar cell performance sensitively depends on the interface and morphology of the cathode, which can be influenced by varying the composition and layer structure of the metal contact. We investigate various metal combinations, such as 3 nm Al\\/8 nm

J. Meiss; M. K. Riede; K. Leo

2009-01-01

312

Solar cell degradation in proton radiation orbits  

NASA Technical Reports Server (NTRS)

Significant discrepancies have been observed between predicted and actual in-orbit silicon solar array degradation in orbits other than LEO (low Earth orbits) and GEO (geosynchronous orbit). These discrepancies have been diagnosed to arise probably from a combination of a lack of appropriate solar cell test data and from inadequacies in the models that relate the unidirectional and mono-energetic proton test data to the omnidirectional flux-energy spectra actually found in orbit. Relative damage coefficients and solar cell power outputs were discussed, and also were presented in graph form. Silicon and gallium arsenide solar cells were considered.

Rauschenbach, H. S.; Yaung, J. Y.

1984-01-01

313

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

314

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

315

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

316

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

317

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

318

Efficient organic solar cells based on phthalocyanines  

Microsoft Academic Search

The primary goal of this thesis is to develop efficient organic solar cells by utilizing metallophthalocyanines (MPc) as donor materials. The role of centered metals in MPcs is discussed, and it is shown that a suitable choice of centered metals and device engineering lead to efficient MPc based solar cells. The effect of molecular packing of organic semiconductors on interfacial

Inho Kim

2010-01-01

319

50% Efficient Solar Cell Architectures and Designs  

Microsoft Academic Search

Very High Efficiency Solar Cells (VHESC) for portable applications [1] that operate at greater than 55 percent efficiency in the laboratory and 50 percent in production are being created. We are integrating the optical design with the solar cell design, and have entered previously unoccupied design space that leads to a new paradigm. This project requires us to invent, develop

Allen Barnett; Christiana Honsberg; Douglas Kirkpatrick; Sarah Kurtz; Duncan Moore; David Salzman; R. Schwartz; J. Gray; S. Bowden; K. Goossen; M. Haney; D. Aiken; M. Wanlass; K. Emery

2006-01-01

320

Hybrid solar cells of micro/mesoporous Zn( and its graphite composites sensitized by CdSe quantum dots  

NASA Astrophysics Data System (ADS)

Quantum efficiencies (QEs) of innovative hybrid solar cells fabricated using micro/mesoporous zinc (hydr)oxide and its graphite-based composites sensitized by semiconductor quantum dots (SQDs) are reported. High absorption coefficient of CdSe SQDs and the wide band gap of zinc (hydr)oxide and its composites with graphite oxide (GO) are essential to achieve solar cells of higher QEs. Hybrid solar cells are fabricated from zinc (hydr)oxide and its composites (with 2 and 5 wt.% of graphite oxides, termed as, ZnGO-2 and ZnGO-5, respectively) while using potassium iodide or perovskite as an electrolyte. A two-photon fluorescence (TPF) imaging technique was used to determine the internal structure of the solar cell device. The photocurrent and current-voltage measurements were used to measure short-circuit current and open-circuit voltage to calculate the fill factor and QE of these solar cells. The highest QE (up to 10.62%) is realized for a ZnGO-2-based solar cell using potassium iodide as its electrolyte and the CdSe quantum dot as its sensitizer.

Islam, SM Z.; Gayen, Taposh; Tint, Naing; Shi, Lingyan; Ebrahim, Amani M.; Seredych, Mykola; Bandosz, Teresa J.; Alfano, Robert

2014-01-01

321

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

322

Zinc deficiency impairs neuronal precursor cell proliferation and induces apoptosis via p53-mediated mechanisms.  

PubMed

The potential importance of stem cells in the adult central nervous system (CNS) that cannot only divide, but also participate in neurogenesis, is now widely appreciated. While we know that the trace element zinc is needed for brain development, the role of this essential nutrient in adult stem cell proliferation and neurogenesis has not been investigated. Adult male rats fed a zinc-restricted diet had approximately 50% fewer Ki67-positive stem cells in the subgranular zone (SGZ) and granular cell layer of the dentate gyrus compared to both zinc-adequate and pair-fed controls (p<0.05). Zinc-deficient rats also had a significant increase the number of TUNEL-labeled cells in the SGZ compared to pair-fed rats (p<0.05). To explore the mechanisms responsible for the effects of zinc deficiency, cultured human Ntera-2 (NT2) neuronal precursor cells were deprived of zinc using the chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN). Consistent with the effects of deficiency in vivo, TPEN treatment resulted in a significant decrease in cellular proliferation, as measured by bromodeoxyuridine (BrdU) uptake, and an increase in caspase3/7-dependent apoptosis. These changes were accompanied by increases in nuclear p53. Oligonucleotide arrays, coupled with use of a dominant-negative p53 construct in NT2 cells, identified 14 differentially regulated p53 target genes. In the early phases zinc deficiency, p53 targets responsible for cell cycle arrest were induced. Continuation of deficiency resulted in the induction of a variety of pro-apoptotic genes such as transforming growth factor-beta (TGF-beta) and retinoblastoma-1 (Rb-1), as well as cellular protection genes such as glutathione peroxidase (GPx). These data suggest that zinc plays a role in neurogenesis by regulating p53-dependent molecular mechanisms that control neuronal precursor cell proliferation and survival. PMID:18778698

Corniola, Rikki S; Tassabehji, Nadine M; Hare, Joan; Sharma, Girdhari; Levenson, Cathy W

2008-10-27

323

Esophagobronchial fistula - A rare complication of aluminum phosphide poisoning  

PubMed Central

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

324

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

325

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

PubMed

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 1-2 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

2014-03-01

326

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

327

Heterojunction silicon microwire solar cells.  

PubMed

We report radial heterojunction solar cells of amorphous silicon on crystalline silicon microwires with high surface passivation. While the shortened collection path is exploited to increase the photocurrent, proper choice of the wire radius and the highly passivated surface prevent drastic decrease in the voltage due to high surface-to-volume ratio. The heterojunction is formed by depositing a ?12-16 nm of amorphous silicon on crystalline silicon wires of radius approximately equal to minority carrier diffusion length (?10 ?m). In spite of very short carrier lifetime (<1 ?s), the microwire array devices generate photocurrent of ?30 mA/cm(2), and the same time, voltages close to 600 mV are achieved, leading to efficiency in excess of 12% in extremely short carrier lifetime silicon. We also find that formation of nanocrystallites of silicon in the deposited film results in loss of the expected passivation. PMID:23170984

Gharghi, Majid; Fathi, Ehsanollah; Kante, Boubacar; Sivoththaman, Siva; Zhang, Xiang

2012-12-12

328

Involvement of activation of NADPH oxidase and extracellular signal-regulated kinase (ERK) in renal cell injury induced by zinc.  

PubMed

Zinc is employed as a supplement; however, zinc-related nephropathy is not generally known. In this study, we investigated zinc-induced renal cell injury using a pig kidney-derived cultured renal epithelial cell line, LLC-PK(1), with proximal kidney tubule-like features, and examined the involvement of free radicals and extracellular signal-regulated kinase (ERK) in the cell injury. The LLC-PK(1) cells showed early uptake of zinc (30 microM), and the release of lactate dehydrogenase (LDH), an index of cell injury, was observed 24 hr after uptake. Three hours after zinc exposure, generation of reactive oxygen species (ROS) was increased. An antioxidant, N, N'-diphenyl-p-phenylenediamine (DPPD), inhibited a zinc-related increase in ROS generation and zinc-induced renal cell injury. An NADPH oxidase inhibitor, diphenyleneiodonium (DPI), inhibited a zinc-related increase in ROS generation and cell injury. We investigated translocation from the cytosol fraction of the p67(phox) subunit, which is involved in the activation of NADPH oxidase, to the membrane fraction, and translocation was induced 3 hr after zinc exposure. We examined the involvement of ERK1/2 in the deterioration of zinc-induced renal cell injury, and the association between ERK1/2 and an increase in ROS generation. Six hours after zinc exposure, the activation (phosphorylation) of ERK1/2 was observed. An antioxidant, DPPD, inhibited the zinc-related activation of ERK1/2. An MAPK/ERK kinase (MEK1/2) inhibitor, U0126, almost completely inhibited zinc-related cell injury (the release of LDH), but did not influence ROS generation. These results suggest that early intracellular uptake of zinc by LLC-PK(1) cells causes the activation of NADPH oxidase, and that ROS generation by the activation of the enzyme leads to the deterioration of renal cell injury via the activation of ERK1/2. PMID:15928461

Matsunaga, Yoshiko; Kawai, Yoshiko; Kohda, Yuka; Gemba, Munekazu

2005-05-01

329

Effect of zinc deficiency on betacyanin production in a cell suspension culture of table beet (Beta vulgaris L.).  

PubMed

The effect of microelements in the Linsmaier-Skoog (LS) medium on betacyanin production was investigated in suspension cultures of table beet (Beta vulgaris L.). Removing zinc from the medium resulted in a high betacyanin content of the cells, the betacyanin content of the cells decreasing with increasing zinc concentration in the medium. The betacyanin content of cells cultured in the medium without zinc was twice as high as that in the medium containing 0.03 mM of zinc. In the revised LS medium without zinc, the maximum betacyanin yield was obtained of 590 mg/l from a 21-day culture. PMID:11388482

Akita, T; Hina, Y; Nishi, T

2001-04-01

330

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

2015-02-11

331

Zinc inhibits ethanol-induced HepG2 cell apoptosis  

Microsoft Academic Search

Alcohol consumption produces a variety of metabolic alterations in liver cells, associated with ethanol oxidation and with nonoxidative metabolism of ethanol, among others apoptosis of hepatocytes. As zinc is known as a potent antioxidant and an inhibitor of cell apoptosis, the aim of this paper was to investigate whether zinc supplementation could inhibit ethanol-induced HepG2 apoptosis, and whether this inhibition

Agnieszka Szuster-Ciesielska; Krzysztof Plewka; Jadwiga Daniluk; Martyna Kandefer-Szersze?

2008-01-01

332

Zinc deficiency induces oxidative stress and AP1 activation in 3T3 cells  

Microsoft Academic Search

It has been postulated that one mechanism underlying zinc deficiencyinduced tissue alterations is excessive cellular oxidative damage. In the present study we investigated if zinc deficiency can induce oxidative stress in 3T3 cells and trigger select intracellular responses that have been associated to oxidative stress. Cells were exposed to control media or to chelated media containing 0.5, 5, or 50

Patricia I Oteiza; Michael S Clegg; M. Paola Zago; Carl L Keen

2000-01-01

333

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

334

Nanocomposite enables sensitized solar cell  

NASA Astrophysics Data System (ADS)

Dye Sensitized solar cells (DSSCs) are a promising candidate for next generation photovoltaic panels due to their low cost, easy fabrication process, and relative high efficiency. Despite considerable effort on the advancement of DSSCs, the efficiency has been stalled for nearly a decade due to the complex interplay among various DSSC components. DSSCs consist of a photoanode on a conducting substrate, infiltrated dye for light absorption and electron injection, and an electrolyte to regenerate the dye. On the photoanode is a high band-gap semiconducting material, primarily of a nanostructure morphology of titanium (II) dioxide (TiO2), dye molecules whose molar absorption is typically in the visible spectrum, are adsorbed onto the surface of TiO 2. To improve the current DSSCs, there are many parameters that can be investigated. In a conventional DSSC, a thick semiconducting layer such as the nanoparticle TiO2 layer induces charge separation efficiently while concurrently increasing the charge transport distance, leading the cell to suffer from more charge recombination and deterioration in charge collection efficiency. To improve on this limitation, TiO2 nanowires (NW) and nanotubes (NT) are explored to replace the nanoparticle photoanode. One-dimensional nanostructures are known for the excellent electron transport properties as well as maintaining a relatively high surface area. Hence one of the focuses of this thesis explores at using different morphologies and composition of TiO2 nanostructures to enhance electron collection efficiency. Another challenge in conventional DSSCs is the limit in light absorption of solar irradiation. Dyes are limited to absorption only in the visible range, and have a low molar absorption coefficient in the near infrared (NIR). Tuning dyes is extremely complicated and may have more disadvantages than simply by extending light harvesting. Therefore our strategy is to incorporate quantum dots to replace the dye, as well as prepare a cell for the possibility of co-sensitization, thereby extending the absorption of light in the visible and NIR. The first phase of the thesis involves the synthesis and characterization of the materials used for the cell. We successfully synthesized TiO2 nanowires and nanotubes and characterized them for the use as the photoanode. Both one-dimensional structures proved to have low resistivity, chemical stability, and high density. We also synthesized lead (II) sulfide (PbS) quantum dots (QDs) and explored at modifying their diameter in order to properly control their light harvesting potential into the NIR region. The electron transport kinetics proved to be faster in one-dimensional nanostructure due to their high crystallinity order and reduced elastic scattering of the electrons during transport. Furthermore, quantum dots were synthesized such that their band-gap allowed for the absorption of NIR light. This result extended the harvesting potential of our solar cell and suggests the possibility for co-sensitization in DSSCs using dye molecules and quantum dots. Hence, the focus of this thesis work is to systematically explore a transformative way to fundamentally enhance charge transport and extend light absorption by in the incorporation of two sensitizing agents.

Phuyal, Dibya D.

335

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

336

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

337

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

338

Integration of Solar Cells on Top of CMOS Chips Part I: aSi Solar Cells  

Microsoft Academic Search

We present the monolithic integration of deep- submicrometer complementary metal-oxide-semiconductor (CMOS) microchips with a-Si:H solar cells. Solar cells are manufactured directly on the CMOS chips. The microchips maintain comparable electronic performance, and the solar cells show efficiency values above 7%. The yield of photovoltaic cells on planarized CMOS chips is 92%. This integration allows integrated energy harvesting using established process

Jiwu Lu; Alexey Y. Kovalgin; Karine H. M. van der Werf; Ruud E. I. Schropp; Jurriaan Schmitz

2011-01-01

339

Development of gallium arsenide solar cells  

NASA Technical Reports Server (NTRS)

The potential of ion implantation as a means of developing gallium arsenide solar cells with high efficiency performance was investigated. Computer calculations on gallium arsenide cell characteristics are presented to show the effects of surface recombination, junction space-charge recombination, and built-in fields produced by nonuniform doping of the surface region. The fabrication technology is summarized. Electrical and optical measurements on samples of solar cells are included.

1973-01-01

340

Development of GaAs solar cells  

NASA Technical Reports Server (NTRS)

This is the second quarterly technical report on a program, the goal of which is to achieve high efficiency GaAs solar cells. Analysis was concerned with providing design information for use in experimentally determining optimum solar cell process parameters. The first quarterly report contained the results of those design calculations. Using those results as a guide, experimental work was initiated to determine optimum cell process parameters. The initial results on this phase of the program are reported.

Mcnally, P. J.

1972-01-01

341

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

342

A high amount of dietary zinc changes the expression of zinc transporters and metallothionein in jejunal epithelial cells in vitro and in vivo but does not prevent zinc accumulation in jejunal tissue of piglets.  

PubMed

High dietary zinc concentrations are used to prevent or treat diarrhea in piglets and humans, but long-term adaptation to high zinc supply has yet not been assessed. Intestinal zinc uptake is facilitated through members of zinc transporter families SLC30 (ZnT) and SLC39 (ZIP). Whereas in rodents, regulation of zinc homeostasis at low or adequate zinc supply has been described, such mechanisms are unclear in piglets. A total of 54 piglets were fed diets containing 57 [low dietary zinc (LZn)], 164 [normal dietary zinc (NZn)], or 2425 [high dietary zinc (HZn)] mg/kg dry matter zinc. After 4 wk, 10 piglets/group were killed and jejunal tissues taken for analysis of zinc transporters SLC30A1 (ZnT1), SLC30A2 (ZnT2), SLC30A5 (ZnT5), SLC39A4 (ZIP4), divalent metal transporter 1 (DMT1), and metallothionein-1 (MT). Weight gain was higher (P < 0.05) in pigs fed HZn than in the LZn and NZn groups during the first 2 wk. Food intake did not differ between groups. The digesta and jejunal tissue zinc concentrations were higher (P < 0.05) in the HZn pigs than in NZn and LZn pigs. Expression of ZnT1 was higher (P < 0.05) and ZIP4 lower (P < 0.05) in HZn pigs than in the 2 other groups, whereas expression of ZnT5 and DMT1 did not differ between treatments. Expression of ZnT2 was lower (P < 0.05) in the LZn group than in the HZn and NZn groups. The mRNA expression and protein abundance of MT was higher (P < 0.05) in the HZn group than in the NZn and LZn groups. Studies with intestinal porcine cell line intestinal epithelial cell-J2 confirmed the dose-dependent downregulation of ZIP4 and upregulation of ZnT1 and MT (P < 0.05) with increasing zinc concentration within 24 h. In conclusion, high dietary zinc concentrations increase intracellular zinc, promote increased zinc export from intestinal tissues into extracellular compartments, and decrease zinc uptake from the gut lumen. The adaptive process appears to be established within 24 h; however, it does not prevent tissue zinc accumulation. PMID:23761649

Martin, Lena; Lodemann, Ulrike; Bondzio, Angelika; Gefeller, Eva-Maria; Vahjen, Wilfried; Aschenbach, Jrg Rudolf; Zentek, Jrgen; Pieper, Robert

2013-08-01

343

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

344

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.

345

Metallothionein 1G and zinc sensitize human colorectal cancer cells to chemotherapy.  

PubMed

Metallothioneins (MT) are a family of low molecular weight proteins that are silenced during colorectal cancer progression, mainly through epigenetic mechanisms, and this loss is associated with poor survival. In this article, we show that overexpression of the MT1G isoform sensitizes colorectal cell lines to the chemotherapeutic agents oxaliplatin (OXA) and 5-fluorouracil (5-FU), in part through enhancing p53 and repressing NF-?B activity. Despite being silenced, MTs can be reinduced by histone deacetylase inhibitors such as trichostatin A and sodium butyrate. In fact, this induction contributes to the cytotoxicity of these agents, given that silencing of MTs by siRNAs reduces their growth-inhibitory activities. Zinc ions also potently enhance MT expression and are cytotoxic to cancer cells. We show for the first time that OXA and 5-FU induce higher levels of intracellular labile zinc, as measured using the fluorescent probe FLUOZIN-3, and that such zinc contributes to the activation of p53 and repression of NF-?B. Addition of zinc enhanced growth inhibition by OXA and 5-FU, and was also capable of resensitizing 5-FU-resistant cell lines to levels comparable with sensitive cell lines. This effect was MT independent because silencing MTs did not affect zinc cytotoxicity. In conclusion, we show that MT induction and zinc administration are novel strategies to sensitize colorectal cancer cells to presently utilized chemotherapeutic agents. PMID:24634414

Arriaga, Juan M; Greco, Angela; Mordoh, Jos; Bianchini, Michele

2014-05-01

346

Solar elastosis in conjunctival squamous cell neoplasm.  

PubMed

Aim: To study the role of solar elastosis in the patient's with Conjunctival Squamous Cell Neoplasia (CSCN). Materials and Methods: Paraffin embedded 30 Conjunctival Squamous Cell Neoplasia tissues were studied for the presence of solar elastosis by Verhoeff's stain. Nineteen Squamous Cell Carcinoma (SCC), 6 Carcinoma In Situ (CIS) and 5 Conjunctival Intraepithelial Neoplasia (CIN) specimens were included in the study. Disease free conjunctiva and pterygium tissues were used as negative and positive control respectively. Results: Solar elastosis was found to be present in 19 of 30 (63.3%) Conjunctival Squamous Cell neoplasia specimens. Conclusion: Our study showed the presence of solar elastosis in conjunctival squamous cell neoplasia. Poor socioeconomic condition is an important factor as most of the elastosis positive patients were farmers. PMID:25494114

Deka, A C; Dutta, A M; Sarma, P C; Baruah, K C

2014-01-01

347

Solar cell preparation in thin silicon membranes  

SciTech Connect

Solar cells prepared in a thin ({approx} 30 {micro}m) crystalline silicon membrane with a supporting frame allow an evaluation of the potential of c-Si thin film cells on cheap substrates. In the same time, light-weight and more radiation-hard solar cells may have direct applications in space. This paper studies the fabrication process of solar cells in {approx} 30 {micro}m thick p-Si epitaxial layers, incorporating a p{sup +2}-Si etch-stop/back-surface field layer, using KOH etching. Wax, rubber and silicon nitride were tested as masking material during the etching. It was found that both wax and silicon nitride could be used as materials for masking of supporting frames for the solar cell thinning up to 30 {micro}m. However, silicon nitride does not reliably protect the frontside structure.

Libezny, M.; Poortmans, J.; Caymax, M.; Beaucarne, G.; Laureys, W.; Nijs, J. [IMEC, Leuven (Belgium)

1997-12-31

348

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

349

Photothermal radiometer for concentrator solar cell measurements  

SciTech Connect

A photothermal technique for measuring the intensity of concentrated sunlight is described. In this technique chopped concentrated sunlight is allowed to impinge on a black metal plate, to produce a time-varying surface temperature, which is measured by an infrared radiometer followed by a lock-in amplifier. By calibrating this system with a solar cell in the range in which the cell short-circuit current is known to vary linearly with light intensity, high ratios of solar concentration can be determined. Using this technique, we found the short-circuit current of an n p solar cell to be linear with concentration up to 410 suns.

Birkeland, J.D.; Kaufman, I.; Backus, C.E.

1986-03-01

350

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

351

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

352

Gastrointestinal hemorrhage in aluminum phosphide poisoning.  

PubMed

Poisoning, both accidental and intentional, is a significant contributor to the mortality and morbidity throughout the world. The commonest pesticide poisoning is organophosphates followed by phosphides. Ingestion of phosphides can induce severe gastrointestinal irritation leading to hemorrhage and ulcerations. Gastrointestinal hemorrhages and ulcerations beyond the duodenum have not been reported in the literature. Here, we report a case of severe hemorrhages and ulcerations in stomach, duodenum, jejunum, and ileum observed in a 45-year-old male who had consumed five tablets of Celphos() (each 3g with 56% aluminum phosphide and 44% Ammonium carbonate) to commit suicide. He started vomiting after consumption, and the vomitus was blood-tinged. Once the treatment was instituted, he was stable for a day and thereafter his condition gradually deteriorated. He died on the 4th day of hospitalization, and autopsy revealed features of multiorgan failure and extensive gastrointestinal hemorrhages. PMID:25098904

Hugar, Basappa S; Praveen, Shivaramareddy; Hosahally, Jayanth S; Kainoor, Sunilkumar; Shetty, Akshith Raj S

2015-01-01

353

Indium oxide/n-silicon heterojunction solar cells  

DOEpatents

A high photo-conversion efficiency indium oxide/n-silicon heterojunction solar cell is spray deposited from a solution containing indium trichloride. The solar cell exhibits an Air Mass One solar conversion efficiency in excess of about 10%.

Feng, Tom (Morris Plains, NJ); Ghosh, Amal K. (New Providence, NJ)

1982-12-28

354

Zinc regulates iNOS-derived nitric oxide formation in endothelial cells.  

PubMed

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

355

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

356

Materials refining for solar cell silicon  

NASA Astrophysics Data System (ADS)

Metallurgical refining processes for the production of solar cell silicon are described. The aim is to obtain an optimum purification effect with a minimum of process steps. The characterization of refined silicon is limited to chemical purity and its correlation with solar quality. Hydrometallurgical refining and pyrometallurgical refining (liquid-liquid extraction, liquid-gas extraction, and recrystallization in aluminum) are treated.

Dietl, J.

357

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

358

Solvent-free ZnO dye-sensitised solar cells  

Microsoft Academic Search

Dye-sensitised solar cells (DSSC) based on commercial nanostructured zinc oxide combined with imidazolium-based room temperature ionic-liquid electrolytes are characterized. The electrolytes are based on a binary mixture of two ionic liquids, one of them used as source of iodide ions. The composition of this solvent-free electrolyte is optimized with respect to the concentration of iodine and iodide and the effect

Elena Guilln; C. Fernndez-Lorenzo; R. Alcntara; J. Martn-Calleja; J. A. Anta

2009-01-01

359

CBD grown ZnO-based gas sensors and dye-sensitized solar cells  

Microsoft Academic Search

Chemical bath deposition (CBD) is used for depositing different metal chalcogenide and oxide thin films through an ion-by-ion or by adsorption of colloidal particles from the solution on the substrate. In this review, we focused our intension on CBD zinc oxide (ZnO) films synthesis with different proposed deposition mechanisms and their integration into gas sensor and dye-sensitized solar cells. Due

C. D. Lokhande; P. M. Gondkar; Rajaram. S. Mane; V. R. Shinde; Sung-Hwan Han

2009-01-01

360

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

361

* Corresponding author. Solar Energy Materials & Solar Cells 58 (1999) 209}218  

E-print Network

* Corresponding author. Solar Energy Materials & Solar Cells 58 (1999) 209}218 A highly e$cient and stable CdTe/CdS thin "lm solar cell N. Romeo, A. Bosio, R. Tedeschi*, A. Romeo, V. Canevari Dipartimento$cient and stable CdTe/CdS thin "lm solar cells. Our cells are prepared in three subsequent phases. Firstly, we

Romeo, Alessandro

362

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

363

Towards high performance inverted polymer solar cells  

NASA Astrophysics Data System (ADS)

Bulk heterojunction polymer solar cells that can be fabricated by solution processing techniques are under intense investigation in both academic institutions and industrial companies because of their potential to enable mass production of flexible and cost-effective alternative to silicon-based electronics. Despite the envisioned advantages and recent technology advances, so far the performance of polymer solar cells is still inferior to inorganic counterparts in terms of the efficiency and stability. There are many factors limiting the performance of polymer solar cells. Among them, the optical and electronic properties of materials in the active layer, device architecture and elimination of PEDOT:PSS are the most determining factors in the overall performance of polymer solar cells. In this presentation, I will present how we approach high performance of polymer solar cells. For example, by developing novel materials, fabrication polymer photovoltaic cells with an inverted device structure and elimination of PEDOT:PSS, we were able to observe over 8.4% power conversion efficiency from inverted polymer solar cells.

Gong, Xiong

2013-03-01

364

Atmospheric pressure chemical vapor deposition of transparent conducting films of fluorine doped zinc oxide and their application  

E-print Network

crystal flat panel displays, energy efficient windows, gas sensors, surface acoustic wave devices loss or diffusion, which can lead to degra- dation in solar cell efficiency. Zinc oxide is more stable conducting oxides. This suggests zinc oxide may lead to higher solar cell efficiency than tin oxide

365

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...

366

Dye-sensitized solar cells  

DOEpatents

A low-cost dye-sensitized Schottky barrier solar cell is comprised of a substrate of semiconductor with an ohmic contact on one face, a sensitizing dye adsorbed onto the opposite face of the semiconductor, a transparent thin-film layer of a reducing agent over the dye, and a thin-film layer of metal over the reducing agent. The ohmic contact and metal layer constitute electrodes for connection to an external circuit and one or the other or both are made transparent to permit light to penetrate to the dye and be absorbed therein for generating electric current. The semiconductor material chosen to be the substrate is one having a wide bandgap and which therefore is transparent; the dye selected is one having a ground state within the bandgap of the semiconductor to generate carriers in the semiconductor, and a first excited state above the conduction band edge of the semiconductor to readily conduct electrons from the dye to the semiconductor; the reducing agent selected is one having a ground state above the ground state of the sensitizer to provide a plentiful source of electrons to the dye during current generation and thereby enhance the generation; and the metal for the thin-film layer of metal is selected to have a Fermi level in the vicinity of or above the ground state of the reducing agent to thereby amply supply electrons to the reducing agent. 3 figs.

Skotheim, T.A.

1980-03-04

367

Dye-sensitized solar cells  

DOEpatents

A low-cost dye-sensitized Schottky barrier solar cell comprised of a substrate of semiconductor with an ohmic contact on one face, a sensitizing dye adsorbed onto the opposite face of the semiconductor, a transparent thin-film layer of a reducing agent over the dye, and a thin-film layer of metal over the reducing agent. The ohmic contact and metal layer constitute electrodes for connection to an external circuit and one or the other or both are made transparent to permit light to penetrate to the dye and be absorbed therein for generating electric current. The semiconductor material chosen to be the substrate is one having a wide bandgap and which therefore is transparent; the dye selected is one having a ground state within the bandgap of the semiconductor to generate carriers in the semiconductor, and a first excited state above the conduction band edge of the semiconductor to readily conduct electrons from the dye to the semiconductor; the reducing agent selected is one having a ground state above the ground state of the sensitizer to provide a plentiful source of electrons to the dye during current generation and thereby enhance the generation; and the metal for the thin-film layer of metal is selected to have a Fermi level in the vicinity of or above the ground state of the reducing agent to thereby amply supply electrons to the reducing agent.

Skotheim, Terje A. [Berkeley, CA

1980-03-04

368

Heavily doped polysilicon-contact solar cells  

NASA Technical Reports Server (NTRS)

The first use of a (silicon)/heavily doped polysilicon)/(metal) structure to replace the conventional high-low junction or back-surface-field (BSF) structure of silicon solar cells is reported. Compared with BSF and back-ohmic-contact (BOC) control samples, the polysilicon-back solar cells show improvements in red spectral response (RSR) and open-circuit voltage. Measurement reveals that a decrease in effective surface recombination velocity S is responsible for this improvement. Decreased S results for n-type (Si:As) polysilicon, consistent with past findings for bipolar transistors, and for p-type (Si:B) polysilicon, reported here for the first time. Though the present polysilicon-back solar cells are far from optimal, the results suggest a new class of designs for high efficiency silicon solar cells. Detailed technical reasons are advanced to support this view.

Lindholm, F. A.; Neugroschel, A.; Arienzo, M.; Iles, P. A.

1985-01-01

369

Inexpensive silicon sheets for solar cells  

NASA Technical Reports Server (NTRS)

Technique of producing silicon sheets by drawing gridlike or porous graphite gauze through silicon melt is readily adaptable to mass production, making process applicable to inexpensive manufacture of solar cell arrays.

Ciszek, T. F.; Schwuttke, G. H.

1977-01-01

370

Solar cell array design handbook, volume 1  

NASA Technical Reports Server (NTRS)

Twelve chapters discuss the following: historical developments, the environment and its effects, solar cells, solar cell filters and covers, solar cell and other electrical interconnections, blocking and shunt diodes, substrates and deployment mechanisms, material properties, design synthesis and optimization, design analysis, procurement, production and cost aspects, evaluation and test, orbital performance, and illustrative design examples. A comprehensive index permits rapid locating of desired topics. The handbook consists of two volumes: Volume 1 is of an expository nature while Volume 2 contains detailed design data in an appendix-like fashion. Volume 2 includes solar cell performance data, applicable unit conversion factors and physical constants, and mechanical, electrical, thermal optical, magnetic, and outgassing material properties. Extensive references are provided.

Rauschenbach, H. S.

1976-01-01

371

Texturization of multicrystalline silicon solar cells  

E-print Network

A significant efficiency gain for crystalline silicon solar cells can be achieved by surface texturization. This research was directed at developing a low-cost, high-throughput and reliable texturing method that can create ...

Li, Dai-Yin

2010-01-01

372

Rational design of hybrid organic solar cells  

E-print Network

In this thesis, we will present a novel design for a nano-structured organic-inorganic hybrid photovoltaic material that will address current challenges in bulk heterojunction (BHJ) organic-based solar cell materials. ...

Lentz, Levi (Levi Carl)

2014-01-01

373

Double-walled carbon nanotube solar cells.  

PubMed

We directly configured double-walled carbon nanotubes as energy conversion materials to fabricate thin-film solar cells, with nanotubes serving as both photogeneration sites and a charge carriers collecting/transport layer. The solar cells consist of a semitransparent thin film of nanotubes conformally coated on a n-type crystalline silicon substrate to create high-density p-n heterojunctions between nanotubes and n-Si to favor charge separation and extract electrons (through n-Si) and holes (through nanotubes). Initial tests have shown a power conversion efficiency of >1%, proving that DWNTs-on-Si is a potentially suitable configuration for making solar cells. Our devices are distinct from previously reported organic solar cells based on blends of polymers and nanomaterials, where conjugate polymers generate excitons and nanotubes only serve as a transport path. PMID:17608444

Wei, Jinquan; Jia, Yi; Shu, Qinke; Gu, Zhiyi; Wang, Kunlin; Zhuang, Daming; Zhang, Gong; Wang, Zhicheng; Luo, Jianbin; Cao, Anyuan; Wu, Dehai

2007-08-01

374

Solar Cell Efficiency Tables (Version 39)  

SciTech Connect

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since July 2011 are reviewed.

Green, M. A.; Emery, K.; Hishikawa, Y.; Warta, W.; Dunlop, E. D.

2012-01-01

375

Monolithic solar cell panel of amorphous silicon  

Microsoft Academic Search

A monolithic solar cell panel has been fabricated using hydrogenated amorphous silicon (a-Si:H) as the semiconductor material. This device consists of a plate glass substrate bearing a number of long, narrow, parallel cells electrically connected in series along the lengths of the cells. It features several characteristics which make it uniquely attractive for large area devices (up to several sq

J. J. Hanak

1979-01-01

376

Terrestrial solar cells present and future  

Microsoft Academic Search

In this paper the principles of operation of various types of solar cell are described. Progress in photovoltaics is traced through the development of the monocrystalline silicon cell for space applications where the emphasis is upon reliability and power\\/weight ratio, to terrestrial cells where the emphasis is upon low-cost production. The role of other contenders such as polycrystalline silicon, amorphous

B. T. Debney; J. R. Knight

1978-01-01

377

Composite solar cell matrix is reliable, lightweight and flexible  

NASA Technical Reports Server (NTRS)

Conducting strips mechanically and electrically connect individual solar cells into a linear array of cells, called a solar submodule, and then connect in series two or more submodules to form a solar cell matrix. Tiny perforations in the strip make it easy to solder them directly to the individual solar cells.

Yasui, R. K.

1967-01-01

378

Free zinc ions outside a narrow concentration range are toxic to a variety of cells in vitro  

PubMed Central

The zinc(II) ion has recently been implicated in a number of novel functions and pathologies in loci as diverse as the brain, retina, small intestine, prostate, heart, pancreas and immune system. Zinc ions are a required nutrient but elevated concentrations are known to kill cells in vitro. Paradoxical observations regarding zincs effects have appeared frequently in the literature, and often their physiological relevance is unclear. We found that for PC-12, HeLa and HT-29 cell lines as well as primary cultures of cardiac myocytes and neurons in vitro in differing media, approximately 5 nmol/L free zinc (pZn = 8.3, where pZn is defined as ? log10 [free Zn2+]) produced apparently healthy cells, but 20-fold higher or (in one case) lower concentrations were usually harmful as judged by multiple criteria. These results indicate that (1) the free zinc ion levels of media should be controlled with a metal ion buffer; (2) adding zinc or strong zinc ligands to an insufficiently buffered medium may lead to unpredictably low or high free zinc levels that are often harmful to cells; and (3) it is generally desirable to measure free zinc ion levels due to the presence of contaminating zinc in many biochemicals and unknown buffering capacity of many media. PMID:20511678

Bozym, Rebecca A; Chimienti, Fabrice; Giblin, Leonard J; Gross, Gunter W; Korichneva, Irina; Li, Yuan; Libert, Sarah; Maret, Wolfgang; Parviz, Maryam; Frederickson, Christopher J; Thompson, Richard B

2010-01-01

379

Characterization of a subfamily of zinc finger genes expressed in human hematopoietic cell lines  

Microsoft Academic Search

We isolated by low strigency screening of a human erythroleukemia cDNA library (K562) 45 indipendent clones hybridizing to a Kruppel-like (HF.10) zinc finger cDNA. The expression of 15 such cDNAs in human hematopoietic cell lines was investigated. Preliminary sequence analysis of the zinc finger motifs in these cDNAs indicate that they belong to a subclass of the Cys-Cys\\/His-His motif, showing

M. Munaro; D. Petroni; M. Di Fazio; P. Comi; S. Ottolenghi

1991-01-01

380

Nanowire dye-sensitized solar cells  

Microsoft Academic Search

Excitonic solar cells-including organic, hybrid organic-inorganic and dye-sensitized cells (DSCs)-are promising devices for inexpensive, large-scale solar energy conversion. The DSC is currently the most efficient and stable excitonic photocell. Central to this device is a thick nanoparticle film that provides a large surface area for the adsorption of light-harvesting molecules. However, nanoparticle DSCs rely on trap-limited diffusion for electron transport,

Matt Law; Lori E. Greene; Justin C. Johnson; Richard Saykally; Peidong Yang

2005-01-01

381

Stretchable, wearable dye-sensitized solar cells.  

PubMed

A stretchable, wearable dye-sensitized solar-cell textile is developed from elastic, electrically conducting fiber as a counter electrode and spring-like titanium wire as the working electrode. Dyesensitized solar cells are demonstrated with energy-conversion efficiencies up to 7.13%. The high energy-conversion efficiencies can be well maintained under stretch by 30% and after stretch for 20 cycles. PMID:24648169

Yang, Zhibin; Deng, Jue; Sun, Xuemei; Li, Houpu; Peng, Huisheng

2014-05-01

382

High-temperature Solar Cell Development  

NASA Technical Reports Server (NTRS)

The vast majority of space probes to date have relied upon photovoltaic power generation. If future missions designed to probe environments close to the sun (Figure 1) will be able to use such power generation, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. The significant problem is that solar cells lose performance at high temperatures.

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

2005-01-01

383

Solar thermal decomposition of zinc oxide in aerosol flow for renewable hydrogen production  

NASA Astrophysics Data System (ADS)

Hydrogen could be a clean replacement for fossil fuels. The Zn/ZnO solar thermochemical water-splitting cycle provides a renewable path to this fuel. Thermodynamic simulations showed that the Zn/ZnO cycle has the lowest temperature of all two-step metal oxide cycles, and the prediction of relatively high efficiency based on its lower temperature and number of steps led to its selection for further study. A rapid aerosol configuration for ZnO decomposition was chosen based on expectation of high reaction rates and small product particle production, and proof-of-concept experiments confirmed this assumption. Thermogravimetric studies of the thermal decomposition kinetics of ZnO showed that the rate followed a 2/3 order L'vov kinetic expression. The activation energy was found to be 353 +/- 25.9 kJ/mol, and a simple electrostatic model was used to describe the reaction mechanism. The pre-exponential factor was found, as expected, to vary inversely with the distance to a product concentration sink. Investigation of the aerosol decomposition of ZnO showed high forward conversion (60%) but low net yield (18%) of zinc due to recombination of product oxygen with nucleated zinc particles. Products that were initially converted had high surface area (15.5 +/- 0.13 g/m2), small particle size (5-70 nm), and relatively spherical morphology, properties desirable when considering the hydrolysis step of the water-splitting cycle. Rates in the aerosol reactor were found to be three orders of magnitude greater than those in a stationary configuration. Computational fluid dynamics (CFD) simulations of the aerosol reaction showed rapid particle heating and high forward conversion (>90%) in short residence times (<1.5s). Results could be used to scale a commercial size reactor, and the recommended particle size based on conversion and handling considerations was 1 mum. Reactor materials sensitive to oxidation were shown to be inappropriate for application due to high corrosion rates. Experiments showed poor stability of the protective SiO2 film in the presence of ZnO, consistent with thermodynamic simulation. CFD simulation of a fluid-wall reactor predicted that such a strategy would be effective at preventing particle-wall contact, but would fare poorly at preventing gas-wall corrosion reactions, a conclusion verified experimentally in a solar reactor.

Perkins, Christopher Michael

384

Fabrication of nanostructured CIGS solar cells  

NASA Astrophysics Data System (ADS)

We present the work on Cu(In,Ga)(Se,S)2 based nanostructured solar cells based on nanowire arrays. CIGS as the light absorber for thin-film solar cells has been widely studied recently, due to its high absorption coefficient, long-term stability, and low-cost of fabrication. Recently, solution phase processed CIGS thin film solar cells attracted great attention due to their extremely low fabrication cost. However, the performance is lower than vacuum based thin films possibly due to higher density of defects and lower carrier mobility. On the other hand, one dimensional ordered nanostructures such as nanowires and nanorods can be used to make redial junction solar cells, where the orthogonality between light absorption and charge carrier separation can lead to enhanced PV performance. Since the charge carriers only need to traverse a short distance in the radial direction before they are separated at the heterojunction interface, the radial junction scheme can be more defect tolerant than their planar junction scheme. In this work, a wide band gap nanowire or nanotube array such as TiO2 is used as a scaffold where CIGS is conformally coated using solution phase to obtain a radial heterojunction solar cell. Their performance is compared that of the planar thin film solar cells fabricated with the same materials.

Zhang, Hongwang; Wang, Fang; Parry, James; Perera, Samanthe; Zeng, Hao

2012-02-01

385

Perovskite solar cells: from materials to devices.  

PubMed

Perovskite solar cells based on organometal halide light absorbers have been considered a promising photovoltaic technology due to their superb power conversion efficiency (PCE) along with very low material costs. Since the first report on a long-term durable solid-state perovskite solar cell with a PCE of 9.7% in 2012, a PCE as high as 19.3% was demonstrated in 2014, and a certified PCE of 17.9% was shown in 2014. Such a high photovoltaic performance is attributed to optically high absorption characteristics and balanced charge transport properties with long diffusion lengths. Nevertheless, there are lots of puzzles to unravel the basis for such high photovoltaic performances. The working principle of perovskite solar cells has not been well established by far, which is the most important thing for understanding perovksite solar cells. In this review, basic fundamentals of perovskite materials including opto-electronic and dielectric properties are described to give a better understanding and insight into high-performing perovskite solar cells. In addition, various fabrication techniques and device structures are described toward the further improvement of perovskite solar cells. PMID:25358818

Jung, Hyun Suk; Park, Nam-Gyu

2015-01-01

386

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

387

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

388

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

389

Influence of zinc deficiency on AKT-MDM2-P53 signaling axes in normal and malignant human prostate cells  

Technology Transfer Automated Retrieval System (TEKTRAN)

With prostate being the highest zinc-accumulating tissue before the onset of cancer, the effects of physiologic levels of zinc on Akt-Mdm2-p53 and Akt-p21 signaling axes in human normal prostate epithelial cells (PrEC) and malignant prostate LNCaP cells were examined. Cells were cultured for 6 d in...

390

Multijunction Solar Cells Optimized for the Mars Surface Solar Spectrum  

NASA Technical Reports Server (NTRS)

This paper gives an update on the performance of the Mars Exploration Rovers (MER) which have been continually performing for more than 3 years beyond their original 90-day missions. The paper also gives the latest results on the optimization of a multijunction solar cell that is optimized to give more power on the surface of Mars.

Edmondson, Kenneth M.; Fetzer, Chris; Karam, Nasser H.; Stella, Paul; Mardesich, Nick; Mueller, Robert

2007-01-01

391

Molecular solution processing of metal chalcogenide thin film solar cells  

NASA Astrophysics Data System (ADS)

The barrier to utilize solar generated electricity mainly comes from their higher cost relative to fossil fuels. However, innovations with new materials and processing techniques can potentially make cost effective photovoltaics. One such strategy is to develop solution processed photovoltaics which avoid the expensive vacuum processing required by traditional solar cells. The dissertation is mainly focused on two absorber material system for thin film solar cells: chalcopyrite CuIn(S,Se)2 (CISS) and kesterite Cu2ZnSn(S,Se) 4 organized in chronological order. Chalcopyrite CISS is a very promising material. It has been demonstrated to achieve the highest efficiency among thin film solar cells. Scaled-up industry production at present has reached the giga-watt per year level. The process however mainly relies on vacuum systems which account for a significant percentage of the manufacturing cost. In the first section of this dissertation, hydrazine based solution processed CISS has been explored. The focus of the research involves the procedures to fabricate devices from solution. The topics covered in Chapter 2 include: precursor solution synthesis with a focus on understanding the solution chemistry, CISS absorber formation from precursor, properties modification toward favorable device performance, and device structure innovation toward tandem device. For photovoltaics to have a significant impact toward meeting energy demands, the annual production capability needs to be on TW-level. On such a level, raw materials supply of rare elements (indium for CIS or tellurium for CdTe) will be the bottleneck limiting the scalability. Replacing indium with zinc and tin, earth abundant kesterite CZTS exhibits great potential to reach the goal of TW-level with no limitations on raw material availability. Chapter 3 shows pioneering work towards solution processing of CZTS film at low temperature. The solution processed devices show performances which rival vacuum-based techniques and is partially attributed to the ease in controlling composition and CZTS phase through this technique. Based on this platform, comprehensive characterization on CZTS devices is carried out including solar cells and transistors. Especially defects properties are exploited in Chapter 4 targeting to identify the limiting factors for further improvement on CZTS solar cells efficiency. Finally, molecular structures and precursor solution stability have been explored, potentially to provide a universal approach to process multinary compounds.

Yang, Wenbing

392

Comparative values of advanced space solar cells  

NASA Technical Reports Server (NTRS)

A methodology for deriving a first order dollar value estimate for advanced solar cells which consists of defining scenarios for solar array production and launch to orbit and the associated costs for typical spacecraft, determining that portion affected by cell design and performance and determining the attributable cost differences is presented. Break even values are calculated for a variety of cells; confirming that efficiency and related effects of radiation resistance and temperature coefficient are major factors; array tare mass, packaging and packing factor are important; but cell mass is of lesser significance. Associated dollar values provide a means of comparison.

Slifer, L. W., Jr.

1982-01-01

393

Recovery of Metal Values from Spent Zinc-Carbon Dry Cell Batteries  

NASA Astrophysics Data System (ADS)

Spent zinc-carbon dry cell batteries were characterized in the process of recovery of metal values. Zinc, manganese and steel were the major metallic materials constituting 63 % of the weight of spent batteries. Different components of the spent batteries were separately processed to extract the metallic values. A maximum of 92 % of total amount of zinc contained in the anodes could be extracted with a purity of over 99.0 % from the anodes by heating at 600 C for 10 min in presence of 12 % NH4Cl flux. Spent electrolyte paste containing manganese and zinc as major metallic elements, was leached in sulfuric acid solution in presence of hydrogen peroxide as a reducing agent. The optimum condition for leaching was found to be concentration of sulfuric acid: 2.5 M, concentration of hydrogen peroxide: 10 %, temperature: 60 C, stirring speed: 600 rpm and solid/liquid ratio 1:12. A maximum of 88 % manganese contained in the paste could be dissolved within 27 min of leaching under the optimized conditions. Dissolution of zinc under the same conditions was 97 %. A maximum of 69.89 % of manganese and 83.29 % of zinc contained in the leach liquor could be precipitated in the form of manganese carbonate and zinc oxalate.

Khan, Majharul Haque; Gulshan, Fahmida; Kurny, A. S. W.

2013-04-01

394

Nanocrystalline silicon based thin film solar cells  

NASA Astrophysics Data System (ADS)

Amorphous silicon solar cells and panels on glass and flexible substrate are commercially available. Since last few years nanocrystalline silicon thin film has attracted remarkable attention due to its stability under light and ability to absorb longer wavelength portion of solar spectrum. For amorphous silicon/ nanocrystalline silicon double junction solar cell 14.7% efficiency has been achieved in small area and 13.5% for large area modules internationally. The device quality nanocrystalline silicon films have been fabricated by RF and VHF PECVD methods at IACS. Detailed characterizations of the materials have been done. Nanocrystalline films with low defect density and high stability have been developed and used as absorber layer of solar cells.

Ray, Swati

2012-06-01

395

Loss of pluripotency in human embryonic stem cells directly correlates with an increase in nuclear zinc.  

SciTech Connect

The pluripotency of human embryonic stem cells (hESCs) is important to investigations of early development and to cell replacement therapy, but the mechanism behind pluripotency is incompletely understood. Zinc has been shown to play a key role in differentiation of non-pluripotent cell types, but here its role in hESCs is directly examined. By mapping the distribution of metals in hESCs at high resolution by x-ray fluorescence microprobe (XFM) and by analyzing subcellular metal content, we have found evidence that loss of pluripotency is directly correlated with an increase in nuclear zinc. Zinc elevation not only redefines our understanding of the mechanisms that support pluripotency, but also may act as a biomarker and an intervention point for stem cell differentiation.

Finney, L.; Vogt, S.; Wolford, J. L.; Chishti, Y.; Jin, Q.; Ward, J.; Chen, L. (Biosciences Division); ( XSD)

2010-01-01

396

Nanoscale Charge Transport in Excitonic Solar Cells  

SciTech Connect

Excitonic solar cells, including all-organic, hybrid organic-inorganic and dye-sensitized solar cells (DSSCs), offer strong potential for inexpensive and large-area solar energy conversion. Unlike traditional inorganic semiconductor solar cells, where all the charge generation and collection processes are well understood, these excitonic solar cells contain extremely disordered structures with complex interfaces which results in large variations in nanoscale electronic properties and has a strong influence on carrier generation, transport, dissociation and collection. Detailed understanding of these processes is important for fabrication of highly efficient solar cells. Efforts to improve efficiency are underway at a large number of research groups throughout the world focused on inorganic and organic semiconductors, photonics, photophysics, charge transport, nanoscience, ultrafast spectroscopy, photonics, semiconductor processing, device physics, device structures, interface structure etc. Rapid progress in this multidisciplinary area requires strong synergetic efforts among researchers from diverse backgrounds. Such effort can lead to novel methods for development of new materials with improved photon harvesting and interfacial treatments for improved carrier transport, process optimization to yield ordered nanoscale morphologies with well defined electronic structures.

Venkat Bommisetty, South Dakota State University

2011-06-23

397

Advanced Solar Cells for Satellite Power Systems  

NASA Technical Reports Server (NTRS)

The multiple natures of today's space missions with regard to operational lifetime, orbital environment, cost and size of spacecraft, to name just a few, present such a broad range of performance requirements to be met by the solar array that no single design can suffice to meet them all. The result is a demand for development of specialized solar cell types that help to optimize overall satellite performance within a specified cost range for any given space mission. Historically, space solar array performance has been optimized for a given mission by tailoring the features of silicon solar cells to account for the orbital environment and average operating conditions expected during the mission. It has become necessary to turn to entirely new photovoltaic materials and device designs to meet the requirements of future missions, both in the near and far term. This paper will outline some of the mission drivers and resulting performance requirements that must be met by advanced solar cells, and provide an overview of some of the advanced cell technologies under development to meet them. The discussion will include high efficiency, radiation hard single junction cells; monolithic and mechanically stacked multiple bandgap cells; and thin film cells.

Flood, Dennis J.; Weinberg, Irving

1994-01-01

398

Uptake epithelia behave in a cell-centric and not systems homeostatic manner in response to zinc depletion and supplementation.  

PubMed

Much remains to be understood about systemic regulation of zinc uptake in vertebrates, and adequate zinc status is far from always achieved in animals or human. In addition to absorbing zinc from the diet, fish are able to take up zinc directly from the water with the gills. This provides an elegant system to study zinc uptake, how it relates to zinc status, and the expression of genes for proteins involved in zinc acquisition. A 21-day experiment was conducted in which zebrafish were acclimated to deficient, control or excess zinc concentrations in the water and feed. Deficient provision of zinc reduced whole body zinc, potassium, sodium and calcium levels whilst zinc concentrations in the uptake epithelia (gills and gut) remained unchanged. Excess levels of zinc caused accumulation of zinc in the gills, intestine and carcass, but impaired whole body iron, sodium and calcium concentrations. Fish subjected to zinc deficiency had, surprisingly, a reduced zinc influx across the gill epithelium, even when tested at a high concentration of zinc in the water. Zinc influx in the excess group was indistinct from the control. Expression of genes for metallothionein-2 (Mt2) and zinc transporters-1, -2, and -8 (Znt1, Znt2, Znt8) in uptake epithelia showed in general a direct relationship with zinc supply, while mRNA for Zip4 was inversely related to zinc supply. Transcripts for the epithelial calcium channel (Ecac/Trpv6) showed time-dependent increased expression in the gills of the deficiency group, and a transient decrease of expression during zinc excess. Transcriptome profiling by microarrays showed that in both gills and intestine, the most markedly affected biological functions were those related to cell growth, proliferation and cancer, closely followed by processes of gene transcription and protein synthesis in general. Whilst changes in zinc supply had profound effects in the intestine on genes associated with uptake and metabolism of macronutrients, many of the unique categories of genes preferentially regulated in the gill could be mapped onto signalling pathways. This included pathways for PPAR/RXR, LXR/RXR, ATM, chemokine, and BMP signalling. Overall, the responses of epithelial tissue to zinc deficiency and excess are best explained by local epithelial homeostasis with no evidence of systemic control. PMID:24301558

Zheng, Dongling; Feeney, Graham P; Handy, Richard D; Hogstrand, Christer; Kille, Peter

2014-01-01

399

Disrupted calcium homeostasis is involved in elevated zinc ion-induced photoreceptor cell death.  

PubMed

Zinc (Zn), the second abundant trace element in living organisms, plays an important role in regulating cell metabolism, signaling, proliferation, gene expression and apoptosis. Meanwhile, the overload of Zn will disrupt the intracellular calcium homeostasis via impairing mitochondrial function. However, the specific molecular mechanism underlying zinc-induced calcium regulation remains poorly understood. In the present study, using zinc chloride (ZnCl2) as a stressor, we investigated the effect of exogenous Zn(2+) in regulating murine photoreceptor cell viability, reactive oxygen species (ROS), cell cycle distribution and calcium homeostasis as well as plasma membrane calcium ATPase (PMCA) isoforms (PMCA1 and PMCA2, i.e., ATP2B1, ATP2B2) expression. We found that the exogenous Zn(2+) in the exposure range (31.25-125.0 ?mol/L) results in the overgeneration of ROS, cell cycle arrest at G2/M phases, elevation of cytosolic [Ca(2+)], inactivation of Ca(2+)-ATPase and reduction of both PMCA1 and PMCA2 in 661 W cells, and thus induces cell death. In conclusion, ZnCl2 exposure can elevate the cytosolic [Ca(2+)], disrupt the intracellular calcium homeostasis, further initiate Ca(2+)-dependent signaling pathway in 661 W cells, and finally cause cell death. Our results will facilitate the understanding of cell death induced by the zinc ion-mediated calcium homeostasis disruption. PMID:25051343

Guo, Dadong; Du, Yuxiang; Wu, Qiuxin; Jiang, Wenjun; Bi, Hongsheng

2014-10-15

400

Nanoparticle Solar Cell Final Technical Report  

SciTech Connect

The purpose of this work was to demonstrate all-inorganic nanoparticle-based solar cells with photovoltaic performance extending into the near-IR region of the solar spectrum as a pathway towards improving power conversion efficiencies. The field of all-inorganic nanoparticle-based solar cells is very new, with only one literature publication in the prior to our project. Very little is understood regarding how these devices function. Inorganic solar cells with IR performance have previously been fabricated using traditional methods such as physical vapor deposition and sputtering, and solution-processed devices utilizing IR-absorbing organic polymers have been investigated. The solution-based deposition of nanoparticles offers the potential of a low-cost manufacturing process combined with the ability to tune the chemical synthesis and material properties to control the device properties. This work, in collaboration with the Sue Carter research group at the University of California, Santa Cruz, has greatly expanded the knowledge base in this field, exploring multiple material systems and several key areas of device physics including temperature, bandgap and electrode device behavior dependence, material morphological behavior, and the role of buffer layers. One publication has been accepted to Solar Energy Materials and Solar Cells pending minor revision and another two papers are being written now. While device performance in the near-IR did not reach the level anticipated at the beginning of this grant, we did observe one of the highest near-IR efficiencies for a nanoparticle-based solar cell device to date. We also identified several key parameters of importance for improving both near-IR performance and nanoparticle solar cells in general, and demonstrated multiple pathways which showed promise for future commercialization with further research.

Breeze, Alison, J; Sahoo, Yudhisthira; Reddy, Damoder; Sholin, Veronica; Carter, Sue

2008-06-17

401

Pleural effusion in aluminum phosphide poisoning  

PubMed Central

Aluminium phosphide (ALP) is a common agrochemical pesticide poisoning with high mortality rate. Primary manifestations are due to myocardial and gastrointestinal involvement. Pleural effusion in ALP poisoning is occasionally reported. We report a case of pleural effusion that developed after ALP ingestion and resolved along with recovery from poisoning. PMID:23243353

Garg, Kranti; Mohapatra, Prasanta R.; Sodhi, Mandeep K.; Janmeja, Ashok K.

2012-01-01

402

Transition Metal Phosphide Hydroprocessing Catalysts: A review  

SciTech Connect

The diminishing quality of oil feedstocks coupled with increasingly more stringent environmental regulations limiting the content of sulfur in transportation fuels have given rise to a need for improved hydroprocessing technology. This review begins with a summary of the major improvements in hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) catalysts and processes that have been reported in recent years. It then describes a new class of hydroprocessing catalysts, the transition metal phosphides, which have emerged as a promising group of high-activity, stable catalysts. The phosphides have physical properties resembling ceramics, so are strong and hard, yet retain electronic and magnetic properties similar to metals. Their crystal structures are based on trigonal prisms, yet they do not form layered structures like the sulfides. They display excellent performance in HDS and HDN, with the most active phosphide, Ni{sub 2}P, having activity surpassing that of promoted sulfides on the basis of sites titrated by chemisorption (CO for the phosphides, O{sub 2} for the sulfides). In the HDS of difficult heteroaromatics like 4,6-dimethyldibenzothiophene Ni{sub 2}P operates by the hydrogenation pathway, while in the HDN of substituted nitrogen compounds like 2-methylpiperidine it carries out nucleophilic substitution. The active sites for hydrogenation in Ni{sub 2}P have a square pyramidal geometry, while those for direct hydrodesulfurization have a tetrahedral geometry. Overall, Ni{sub 2}P is a promising catalyst for deep HDS in the presence of nitrogen and aromatic compounds.

Oyama, S.; Gott, T; Zhao, H; Lee, Y

2009-01-01

403

Development of gallium aluminum phosphide electroluminescent diodes  

NASA Technical Reports Server (NTRS)

Work done on the development of gallium aluminum phosphide alloys for electroluminescent light sources is described. The preparation of this wide band gap semiconductor alloy, its physical properties (particularly the band structure, the electrical characteristics, and the light emitting properties) and work done on the fabrication of diode structures from these alloys are broadly covered.

Chicotka, R. J.; Lorenz, M. R.; Nethercot, A. H.; Pettit, G. D.

1972-01-01

404

MIS silicon solar cells: potential advantages  

SciTech Connect

Recent progress with silicon solar cells based on the MIS or SIS structure is reviewed. To be competitive with pn junction technology in the near term, these cells must be much cheaper or have a higher efficiency in a production environment. Apparently, the minority carrier MIS cells have the greatest potential for large-scale applications. The data currently indicate that all types of MIS/SIS cells have some inherent instability problems.

Cheek, G.; Mertens, R.

1981-05-01

405

Plastic Schottky-barrier solar cells  

DOEpatents

A photovoltaic cell structure is fabricated from an active medium including an undoped polyacetylene, organic semiconductor. When a film of such material is in rectifying contact with a metallic area electrode, a Schottky-barrier junction is obtained within the body of the cell structure. Also, a gold overlayer passivates a magnesium layer on the undoped polyacetylene film. With the proper selection and location of elements a photovoltaic cell structure and solar cell are obtained.

Waldrop, J.R.; Cohen, M.J.

1981-12-30

406

Qualitative and quantitative evaluation of thin-film solar cells using solar cell local characterization  

NASA Astrophysics Data System (ADS)

The light-beam-induced current-based CELLO measurement technique (solar CELl LOcal characterization), originally developed for wafer-based silicon solar cells, can successfully be applied to thin-film solar cells, provided that contacting of a single cell is possible. This is shown exemplarily for several crystalline silicon on glass samples, having varying quality with respect to photocurrent extraction, series resistance, and power losses. For the latter, a comparison with results obtained from dark lock-in thermography gives quantitative agreement, provided that the cells are not severely shunted.

Wagner, J.-M.; Carstensen, J.; Schtt, A.; Fll, H.

2013-02-01

407

Illuminating mobile zinc with fluorescence: From cuvettes to live cells and tissues  

PubMed Central

With the aid of chemoselective sensors, fluorescence microscopy has emerged as an indispensable tool to visualize the distribution and dynamics of various biologically important molecules in live specimens. Motivated by our interest in understanding the chemistry and biology of mobile zinc underlying its physiological and pathological roles, over the past decade our laboratory has developed an extensive library of zinc fluorescence probes. In this article, we provide essential information about our sensor toolbox in order to assist investigators interested to apply our constructs to study various aspects of mobile zinc biology. We illustrate their use with several examples of imaging both exogenous and endogenous mobile zinc in live cells and tissues using various versions of fluorescence microscopy, including confocal and two-photon microscopy. PMID:22289467

Huang, Zhen; Lippard, Stephen J.

2011-01-01

408

Green synthesis of wurtzite copper zinc tin sulfide nanocones for improved solar photovoltaic utilization  

NASA Astrophysics Data System (ADS)

Cu2ZnSnS4 (CZTS) is considered to be one of the most promising light absorbing materials for low-cost and high-efficiency thin-film solar cells. It is composed of earth abundant, non-toxic elements. In the present study, wurtzite CZTS nanocone has been synthesized by a green chemistry route. The nanocones have been characterized for its optical, structural and microstructural properties using UV-Vis spectrophotometer, X-ray diffraction, Raman spectroscopy and high-resolution transmission electron microscopy. Optical absorption result shows a band gap of 1.42 eV. XRD and Raman results show wurtzite structure and TEM studies reveal the nanocone structure of the grown material. Growing vertically aligned nanocone structure having smaller diameter shall help in enhancing the light absorption in broader range which shall enhance the efficiency of solar cell. This study is a step in this direction.

Arora, Leena; Gupta, Poonam; Chhikara, Nitu; Singh, Om Pal; Muhunthan, N.; Singh, V. N.; Singh, B. P.; Jain, Kiran; Chand, S.

2015-02-01

409

Antireflection coatings designed by the average uniform algorithm for thin film solar cells.  

PubMed

Effective coatings improve the performance of any device designed to emit or collect light over a range of angles and wavelengths. Improved broadband and wide angle antireflection coatings (ARCs) are a simple and direct way to improve solar cell performance. In this paper we demonstrate a multilayered ARC optimized using a new meta-heuristic algorithm called the average uniform algorithm (AUA). Comparison between the well-known genetic algorithm and the AUA showed that both achieved similar results but the AUA converged much faster. The coating optimized by AUA for broadband and wide-angle emission is applied to a copper zinc tin sulfide based thin film solar cell by co-sputtering of high and low refractive index material. A significant improvement in efficiency was observed over wide angle and bandwidth with a typical improvement of 15% over the uncoated solar cell. This AUA methodology is proven to be an efficient method for design of general ARCs. PMID:25607956

Rajbhandari, Pravakar P; Emrani, Amin; Dhakal, Tara P; Westgate, Charles R; Klotzkin, David

2014-12-01

410

INKJET PRINTING OF NICKEL AND SILVER METAL SOLAR CELL CONTACTS  

SciTech Connect

With about 125,000 terawatts of solar power striking the earth at any given moment, solar energy may be the only renewable energy resource with enough capacity to meet a major portion of our future energy needs. Thin-fi lm technologies and solution deposition processes seek to reduce manufacturing costs in order to compete with conventional coal-based electricity. Inkjet printing, as a derivative of the direct-write process, offers the potential for low-cost, material-effi cient deposition of the metals for photovoltaic contacts. Advances in contact metallizations are important because they can be employed on existing silicon technology and in future-generation devices. We report on the atmospheric, non-contact deposition of nickel (Ni) and silver (Ag) metal patterns on glass, Si, and ZnO substrates at 180220C from metal-organic precursor inks using a Dimatix inkjet printer. Near-bulk conductivity Ag contacts were successfully printed up to 4.5 ?m thick and 130 ?m wide on the silicon nitride antirefl ective coating of silicon solar cells. Thin, high-resolution Ni adhesion-layer lines were printed on glass and zinc oxide at 80 ?m wide and 55 nm thick with a conductivity two orders of magnitude less than the bulk metal. Additionally, the ability to print multi-layered metallizations (Ag on Ni) on transparent conducting oxides was demonstrated and is promising for contacts in copper-indium-diselenide (CIS) solar cells. Future work will focus on further improving resolution, printing full contact devices, and investigating copper inks as a low-cost replacement for Ag contacts.

Pasquarelli, R.; Curtis, C.; Van Hest, M.

2008-01-01

411

P/N InP solar cells on Ge wafers  

NASA Technical Reports Server (NTRS)

Indium phosphide (InP) P-on-N one-sun solar cells were epitaxially grown using a metalorganic chemical vapor deposition process on germanium (Ge) wafers. The motivation for this work is to replace expensive InP wafers, which are fragile and must be thick and therefore heavy, with less expensive Ge wafers, which are stronger, allowing use of thinner, lighter weight wafers. An intermediate InxGs1-xP grading layer starting as In(0.49)Ga(0.51) at the GaAs-coated Ge wafer surface and ending as InP at the top of the grading layer (backside of the InP cell) was used to attempt to bend some of the threading dislocations generated by lattice-mismatch between the Ge wafer and InP cell so they would be harmlessly confined in this grading layer. The best InP/Ge cell was independently measured by NASA-Lewis with a one-sun 25 C AMO efficiently measured by NASA-Lewis with a one-circuit photocurrent 22.6 mA/sq cm. We believe this is the first published report of an InP cell grown on a Ge wafer. Why get excited over a 9 percent InP/Ge cell? If we look at the cell weight and efficiency, a 9 percent InP cell on an 8 mil Ge wafer has about the same cell power density, 118 W/kg (BOL), as the best InP cell ever made, a 19 percent InP cell on an 18 mil InP wafer, because of the lighter Ge wafer weight. As cell panel materials become lighter, the cell weight becomes more important, and the advantage of lightweight cells to the panel power density becomes more important. In addition, although InP/Ge cells have a low beginning-of-life (BOL) efficiency due to dislocation defects, the InP/Ge cells are very radiation hard (end-of-life power similar to beginning-of-life). We have irradiated an InP/Ge cell with alpha particles to an equivalent fluence of 1.6 x 10(exp 16) 1 MeV electrons/sq cm and the efficiency is still 83 percent of its BOL value. At this fluence level, the power output of these InP/Ge cells matches the GaAs/Ge cell data tabulated in the JPL handbook. Data are presented indicating InP/Ge has more power output than GaAs/Ge cells at fluences in excess of this value.

Wojtczuk, Steven; Vernon, Stanley; Burke, Edward A.

1994-01-01

412

EE Times: Semi News Groups claim breakthroughs in solar cells  

E-print Network

claim to offer nearly twice the efficiency as silicon in solar cells. But solar cells based concentrator photovoltaic (CPV) modules for large- scale solar power generation. Semprius' microEE Times: Semi News Groups claim breakthroughs in solar cells Mark LaPedus Page 1 of 2 EE Times (05

Rogers, John A.

413

Third Working Meeting on Gallium Arsenide Solar Cells  

NASA Technical Reports Server (NTRS)

Research results are reported for GaAs Schottky barrier solar cells, GaAlAs/GaAs heteroface solar cells, and GaAlAs graded band gap solar cells. Related materials studies are presented. A systems study for GaAs and Si solar concentrator systems is given.

Walker, G. H. (compiler)

1976-01-01

414

November 21, 2000 PV Lesson Plan 1 Solar Cells  

E-print Network

November 21, 2000 PV Lesson Plan 1 ­ Solar Cells Prepared for the Oregon Million Solar Roofs High School Gary Grace ­ South Eugene High School In Schools #12;1 Solar Cells Lesson Plan Content: In this lesson, students are introduced to the basic physics and chemistry behind the operation of a solar cell

Oregon, University of

415

Cannabidiol affects the expression of genes involved in zinc homeostasis in BV-2 microglial cells.  

PubMed

Cannabidiol (CBD) has been shown to exhibit anti-inflammatory, antioxidant and neuroprotective properties. Unlike ?(9)-tetrahydrocannabinol (THC), CBD is devoid of psychotropic effects and has very low affinity for both cannabinoid receptors, CB(1) and CB(2). We have previously reported that CBD and THC have different effects on anti-inflammatory pathways in lipopolysaccharide-stimulated BV-2 microglial cells, in a CB(1)/CB(2) independent manner. Moreover, CBD treatment of BV-2 cells, was found to induce a robust change in the expression of genes related to oxidative stress, glutathione deprivation and inflammation. Many of these genes were shown to be controlled by Nrf2 and ATF4 transcription factors. Using the Illumina MouseRef-8 BeadChip platform, DAVID Bioinformatics and Ingenuity Pathway Analysis, we identified functional sets of genes and networks affected by CBD. A subset of genes was found to be regulated by the metal responsive element (MRE)-binding transcription factor-1 (MTF-1) and is shown to be related to zinc homeostasis. We found that CBD upregulates the expression of the mRNAs for metallothionein 2 (Mt2), N-myc-downstream regulated gene 1 and matrix metalloproteinase 23 as well as of the zinc transporters ZnT1/Slc30a1 and Zip4/Slc39a4 but downregulates the expression of the mRNA for the zinc transporter Zip10/Slc39a10 as well as for the zinc finger protein 472. Among these genes, ZnT1, Mt2 and the zinc transporters ZIPs are known to function together to control the intracellular zinc concentration. These results show that CBD, but much less so THC, affects the expression of genes involved in zinc homeostasis and suggest that the regulation of zinc levels could have an important role through which CBD may exert its antioxidant and anti-inflammatory effects. PMID:22178458

Juknat, Ana; Rimmerman, Neta; Levy, Rivka; Vogel, Zvi; Kozela, Ewa

2012-11-01

416

Chemically Deposited Thin-Film Solar Cell Materials  

NASA Technical Reports Server (NTRS)

We have been working on the development of thin film photovoltaic solar cell materials that can be produced entirely by wet chemical methods on low-cost flexible substrates. P-type copper indium diselenide (CIS) absorber layers have been deposited via electrochemical deposition. Similar techniques have also allowed us to incorporate both Ga and S into the CIS structure, in order to increase its optical bandgap. The ability to deposit similar absorber layers with a variety of bandgaps is essential to our efforts to develop a multi-junction thin-film solar cell. Chemical bath deposition methods were used to deposit a cadmium sulfide (CdS) buffer layers on our CIS-based absorber layers. Window contacts were made to these CdS/CIS junctions by the electrodeposition of zinc oxide (ZnO). Structural and elemental determinations of the individual ZnO, CdS and CIS-based films via transmission spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy and energy dispersive spectroscopy will be presented. The electrical characterization of the resulting devices will be discussed.

Raffaelle, R.; Junek, W.; Gorse, J.; Thompson, T.; Harris, J.; Hehemann, D.; Hepp, A.; Rybicki, G.

2005-01-01

417

Quantum molecular dynamics simulations of hydrogen production and solar cells  

NASA Astrophysics Data System (ADS)

The global energy crisis presents two major challenges for scientists around the world: Producing cleaner energy which is sustainable for the environment; And improving the efficiency of energy production as well as consumption. It is crucial and yet elusive to understand the atomistic mechanisms and electronic properties, which are needed in order to tackle those challenges. Quantum molecular dynamics simulations and nonadiabatic quantum molecular dynamics are two of the dominant methods used to address the atomistic and electronic properties in various energy studies. This dissertation is an ensemble of three studies in energy research: (1) Hydrogen production from the reaction of aluminum clusters with water to provide a renewable energy cycle; (2) The photo-excited charge transfer and recombination at a quaterthiophene/zinc oxide interface to improve the power conversion efficiency of hybrid poly(3-hexylthiophene) (P3HT) /ZnO solar cells; and (3) the charge transfer at a rubrene/C60 interface to understand why phenyl groups in rubrene improve the performance of rubrene/C60 solar cells.

Mou, Weiwei

418

Microstructural analysis of solar cell welds  

NASA Astrophysics Data System (ADS)

Parallel-gap resistance welding of silicon solar cells with copper interconnects results in complex microstructural variations that depend on the welding variables. At relatively low heat input solid-state welds are produced. At medium heat the Ag-Cu eutectic forms resulting in a braze joint. High heat produces a fusion weld with complete melting of the silver layer on the silicon solar cell. If the silicon is also melted, cracking occurs in the silicon cell below the weld nugget. These determinations were made using light microscopy, microprobe, and scanning electron microscopy analyses.

Moore, T. J.; Watson, G. K.; Baraona, C. R.

419

Microscopic optoelectronic defectoscopy of solar cells  

NASA Astrophysics Data System (ADS)

Scanning probe microscopes are powerful tool for micro- or nanoscale diagnostics of defects in crystalline silicon solar cells. Solar cell is a large p-n junction semiconductor device. Its quality is strongly damaged by the presence of defects. If the cell works under low reverse-biased voltage, defects emit a light in visible range. The suggested method combines three different measurements: electric noise measurement, local topography and near-field optical beam induced current and thus provides more complex information. To prove its feasibility, we have selected one defect (truncated pyramid) in the sample, which emitted light under low reverse-biased voltage.

karvada, P.; Tomnek, P.; Koktav, P.; Dallaeva, D.

2013-04-01

420

Progress in semicrystalline silicon solar cell fabrication  

NASA Astrophysics Data System (ADS)

Several recent advances made in the fabrication technology of semicrystalline silicon solar cells are reviewed in this paper. Recent work has indicated that: (1) semicrystalline silicon solar cell performance is mainly controlled by intragrain defect densities and not only by the grain boundaries, (2) processing parameters for low cost, high throughput techniques require more optimization when semicrystalline silicon substrates are used, and (3) reasonable cell efficiencies have been achieved using a low cost thin-film epitaxial layer on UMG-Silicon coupled with low cost screen printing technology.

Mertens, R.; Cheek, G.; Depauw, P.; Frisson, L.

421

Understanding intermediate-band solar cells  

Microsoft Academic Search

The intermediate-band solar cell is designed to provide a large photogenerated current while maintaining a high output voltage. To make this possible, these cells incorporate an energy band that is partially filled with electrons within the forbidden bandgap of a semiconductor. Photons with insufficient energy to pump electrons from the valence band to the conduction band can use this intermediate

Antonio Mart; Colin Stanley; Antonio Luque

2012-01-01

422

Glass tubes for protecting solar cells  

NASA Technical Reports Server (NTRS)

Protecting solar cells against environmental effects is accomplished by putting them inside glass tubes instead of hermetically sealing them between pairs of flat glass sheets. If cells are coupled with storage battery integrated into tube, freestanding power source could be built.

Shelpuk, B.

1978-01-01

423

Liquid cooled, linear focus solar cell receiver  

DOEpatents

Separate structures for electrical insulation and thermal conduction are established within a liquid cooled, linear focus solar cell receiver for use with parabolic or Fresnel optical concentrators. The receiver includes a V-shaped aluminum extrusion having a pair of outer faces each formed with a channel receiving a string of solar cells in thermal contact with the extrusion. Each cell string is attached to a continuous glass cover secured within the channel with spring clips to isolate the string from the external environment. Repair or replacement of solar cells is effected simply by detaching the spring clips to remove the cover/cell assembly without interrupting circulation of coolant fluid through the receiver. The lower surface of the channel in thermal contact with the cells of the string is anodized to establish a suitable standoff voltage capability between the cells and the extrusion. Primary electrical insulation is provided by a dielectric tape disposed between the coolant tube and extrusion. Adjacent solar cells are soldered to interconnect members designed to accommodate thermal expansion and mismatches. The coolant tube is clamped into the extrusion channel with a releasably attachable clamping strip to facilitate easy removal of the receiver from the coolant circuit.

Kirpich, A.S.

1983-12-08

424

Liquid cooled, linear focus solar cell receiver  

DOEpatents

Separate structures for electrical insulation and thermal conduction are established within a liquid cooled, linear focus solar cell receiver for use with parabolic or Fresnel optical concentrators. The receiver includes a V-shaped aluminum extrusion having a pair of outer faces each formed with a channel receiving a string of solar cells in thermal contact with the extrusion. Each cell string is attached to a continuous glass cover secured within the channel with spring clips to isolate the string from the external environment. Repair or replacement of solar cells is effected simply by detaching the spring clips to remove the cover/cell assembly without interrupting circulation of coolant fluid through the receiver. The lower surface of the channel in thermal contact with the cells of the string is anodized to establish a suitable standoff voltage capability between the cells and the extrusion. Primary electrical insulation is provided by a dielectric tape disposed between the coolant tube and extrusion. Adjacent solar cells are soldered to interconnect members designed to accommodate thermal expansion and mismatches. The coolant tube is clamped into the extrusion channel with a releasably attachable clamping strip to facilitate easy removal of the receiver from the coolant circuit.

Kirpich, Aaron S. (Broomall, PA)

1985-01-01

425

Method of restoring degraded solar cells  

DOEpatents

Amorphous silicon solar cells have been shown to have efficiencies which degrade as a result of long exposure to light. Annealing such cells in air at a temperature of about 200.degree. C. for at least 30 minutes restores their efficiency.

Staebler, David L. (Lawrenceville, NJ)

1983-01-01

426

Solar Cell Calibration and Measurement Techniques  

NASA Technical Reports Server (NTRS)

The increasing complexity of space solar cells and the increasing international markets for both cells and arrays has resulted in workshops jointly sponsored by NASDA, ESA and NASA. These workshops are designed to obtain international agreement on standardized values for the AMO spectrum and constant, recommend laboratory measurement practices and establish a set of protocols for international comparison of laboratory measurements. A working draft of an ISO standard, WDI 5387, 'Requirements for Measurement and Calibration Procedures for Space Solar Cells' was discussed with a focus on the scope of the document, a definition of primary standard cell, and required error analysis for all measurement techniques. Working groups addressed the issues of Air Mass Zero (AMO) solar constant and spectrum, laboratory measurement techniques, and the international round robin methodology. A summary is presented of the current state of each area and the formulation of the ISO document.

Bailey, Sheila; Brinker, Dave; Curtis, Henry; Jenkins, Phillip; Scheiman, Dave

1997-01-01

427

High efficiency low cost solar cell power  

NASA Technical Reports Server (NTRS)

A concept for generating high-efficiency, low-cost, solar-cell power is outlined with reference to solar cell parameters, optical concentrators, and thermal control procedures. A design for a 12.5-kw power module for space operation is discussed noting the optical system, spectrum splitter, light conversion system, cell cooling, power conditioner, and tracking mechanism. It is found that for an unconcentrated array, efficiency approaches 60% when ten or more bandgaps are used. For a 12-band system, a computer program distributed bandgaps for maximum efficiency and equal cell currents. Rigid materials and thin films have been proposed for optical components and prisms, gratings, and dichroic mirrors have been recommended for spectrum splitting. Various radiator concepts are noted including that of Weatherston and Smith (1960) and Hedgepeth and Knapp (1978). The concept may be suitable for the Solar Power Satellite.

Bekey, I.; Blocker, W.

1978-01-01

428

GaAs solar cell test facility  

NASA Astrophysics Data System (ADS)

A hybrid type (electricity and heat) GaAs solar cell test facility has been made to evaluate total characteristics of GaAs cell and to study the energy conversion system. The size of a solar collector is 3.4 m x 2.1 m and 60 GaAs cells with Fresnel lenses are attached on it. The solar collector is controlled by a microcomputer to track the sun. Electric energy produced by the cells is stored in a lead-acid battery and then supplied to the load through a DC-AC inverter. The microcomputer also controls the data acquisition in parallel with tracking. This paper presents an overview of the facility and the experimental results of power generation obtained to date.

Kawashima, M.; Hosoda, Y.; Suzawa, C.; Shimada, T.; Motoyoshi, K.; Sasatani, Y.

1982-01-01

429

Silicon solar cell process. Development, fabrication and analysis  

NASA Technical Reports Server (NTRS)

Solar cells were fabricated from unconventional silicon sheets, and the performances were characterized with an emphasis on statistical evaluation. A number of solar cell fabrication processes were used and conversion efficiency was measured under AMO condition at 25 C. Silso solar cells using standard processing showed an average efficiency of about 9.6%. Solar cells with back surface field process showed about the same efficiency as the cells from standard process. Solar cells from grain boundary passivation process did not show any improvements in solar cell performance.

Yoo, H. I.; Iles, P. A.; Tanner, D. P.

1978-01-01

430

Printable CIGS thin film solar cells  

NASA Astrophysics Data System (ADS)

Among the various thin film solar cells in the market, CuInGaSe thin film solar cells have been considered as the most promising alternatives to crystalline silicon solar cells because of their high photo-electricity conversion efficiency, reliability, and stability. However, many fabrication methods of CIGS thin film are based on vacuum processes such as evaporation and sputtering techniques which are not cost efficient. This work develops a solution method using paste or ink liquid spin-coated on glass that would be competitive to conventional ways in terms of cost effective, non-vacuum needed, and quick processing. A mixture precursor was prepared by dissolving appropriate amounts of composition chemicals. After the mixture solution was cooled, a viscous paste was prepared and ready for spin-coating process. A slight bluish CIG thin film on substrate was then put in a tube furnace with evaporation of metal Se followed by depositing CdS layer and ZnO nanoparticle thin film coating to complete a solar cell fabrication. Structure, absorption spectrum, and photo-electricity conversion efficiency for the as-grown CIGS thin film solar cell are under study.

Fan, Xiaojuan

2013-03-01

431

Quantum-Tuned Multijunction Solar Cells  

NASA Astrophysics Data System (ADS)

Multijunction solar cells made from a combination of CQDs of differing sizes and thus bandgaps are a promising means by which to increase the energy harvested from the Sun's broad spectrum. In this dissertation, we first report the systematic engineering of 1.6 eV PbS CQD solar cells, optimal as the front cell responsible for visible wavelength harvesting in tandem photovoltaics. We rationally optimize each of the device's collecting electrodes---the heterointerface with electron accepting TiO2 and the deep-work-function hole-collecting MoO3 for ohmic contact---for maximum efficiency. Room-temperature processing enables flexible substrates, and permits tandem solar cells that integrate a small-bandgap back cell atop a low thermal-budget larger-bandgap front cell. We report an electrode strategy that enables a depleted heterojunction CQD PV device to be fabricated entirely at room temperature. We develop a two-layer donor-supply electrode (DSE) in which a highly doped, shallow work function layer supplies a high density of free electrons to an ultrathin TiO2 layer via charge-transfer doping. Using the DSE we build all-room-temperature-processed small-bandgap (1 eV) colloidal quantum dot solar cells suitable for use as the back junction in tandem solar cells. We further report in this work the first efficient CQD tandem solar cells. We use a graded recombination layer (GRL) to provide a progression of work functions from the hole-accepting electrode in the bottom cell to the electron-accepting electrode in the top cell. The recombination layers must allow the hole current from one cell to recombine, with high efficiency and low voltage loss, with the electron current from the next cell. We conclude our dissertation by presenting the generalized conditions for design of efficient graded recombination layer solar devices. We demonstrate a family of new GRL designs experimentally and highlight the benefits of the progression of dopings and work functions in the interlayers.

Koleilat, Ghada I.

432

Ultra-thin GaAs single-junction solar cells integrated with a reflective back scattering layer  

SciTech Connect

This paper reports the proposal, design, and demonstration of ultra-thin GaAs single-junction solar cells integrated with a reflective back scattering layer to optimize light management and minimize non-radiative recombination. According to our recently developed semi-analytical model, this design offers one of the highest potential achievable efficiencies for GaAs solar cells possessing typical non-radiative recombination rates found among commercially available III-V arsenide and phosphide materials. The structure of the demonstrated solar cells consists of an In{sub 0.49}Ga{sub 0.51}P/GaAs/In{sub 0.49}Ga{sub 0.51}P double-heterostructure PN junction with an ultra-thin 300?nm thick GaAs absorber, combined with a 5??m thick Al{sub 0.52}In{sub 0.48}P layer with a textured as-grown surface coated with Au used as a reflective back scattering layer. The final devices were fabricated using a substrate-removal and flip-chip bonding process. Solar cells with a top metal contact coverage of 9.7%, and a MgF{sub 2}/ZnS anti-reflective coating demonstrated open-circuit voltages (V{sub oc}) up to 1.00?V, short-circuit current densities (J{sub sc}) up to 24.5?mA/cm{sup 2}, and power conversion efficiencies up to 19.1%; demonstrating the feasibility of this design approach. If a commonly used 2% metal grid coverage is assumed, the anticipated J{sub sc} and conversion efficiency of these devices are expected to reach 26.6?mA/cm{sup 2} and 20.7%, respectively.

Yang, Weiquan; Becker, Jacob; Liu, Shi; Kuo, Ying-Shen; Li, Jing-Jing; Zhang, Yong-Hang [Center for Photonics Innovation and School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Landini, Barbara; Campman, Ken [Sumika Electronic Materials, Inc., Phoenix, Arizona 85034 (United States)

2014-05-28

433

Ultra-thin GaAs single-junction solar cells integrated with a reflective back scattering layer  

NASA Astrophysics Data System (ADS)

This paper reports the proposal, design, and demonstration of ultra-thin GaAs single-junction solar cells integrated with a reflective back scattering layer to optimize light management and minimize non-radiative recombination. According to our recently developed semi-analytical model, this design offers one of the highest potential achievable efficiencies for GaAs solar cells possessing typical non-radiative recombination rates found among commercially available III-V arsenide and phosphide materials. The structure of the demonstrated solar cells consists of an In0.49Ga0.51P/GaAs/In0.49Ga0.51P double-heterostructure PN junction with an ultra-thin 300 nm thick GaAs absorber, combined with a 5 ?m thick Al0.52In0.48P layer with a textured as-grown surface coated with Au used as a reflective back scattering layer. The final devices were fabricated using a substrate-removal and flip-chip bonding process. Solar cells with a top metal contact coverage of 9.7%, and a MgF2/ZnS anti-reflective coating demonstrated open-circuit voltages (Voc) up to 1.00 V, short-circuit current densities (Jsc) up to 24.5 mA/cm2, and power conversion efficiencies up to 19.1%; demonstrating the feasibility of this design approach. If a commonly used 2% metal grid coverage is assumed, the anticipated Jsc and conversion efficiency of these devices are expected to reach 26.6 mA/cm2 and 20.7%, respectively.

Yang, Weiquan; Becker, Jacob; Liu, Shi; Kuo, Ying-Shen; Li, Jing-Jing; Landini, Barbara; Campman, Ken; Zhang, Yong-Hang

2014-05-01

434

High voltage solar cell power generating system  

NASA Technical Reports Server (NTRS)

A laboratory solar power system regulated by on-panel switches has been delivered for operating high power (3 kW), high voltage (15,000 volt) loads (communication tubes, ion thrusters). The modular system consists of 26 solar arrays, each with an integral light source and cooling system. A typical array contains 2,560 series-connected cells. Each light source consists of twenty 500-watt tungsten iodide lamps providing plus or minus 5 percent uniformity at one solar constant. An array temperature of less than 40 C is achieved using an infrared filter, a water-cooled plate, a vacuum hold-down system, and air flushing.

Levy, E., Jr.; Opjorden, R. W.; Hoffman, A. C.

1974-01-01

435

Methods to evaluate Zinc transport into and out of the secretory and endosomal-lysosomal compartments in DT40 cells.  

PubMed

Zinc plays crucial roles in diverse biological processes. Recently, in addition to zinc mobilization into and out of the cell, zinc mobilization into and out of intracellular organelles, including the secretory and endosomal-lysosomal compartments, has received growing interest. In vertebrate cells, the Zrt/Irt-like proteins (ZIPs) and Zn transporters (ZnTs) are the two major families of zinc transport proteins involved in zinc mobilization across cellular membranes. Importantly, nearly half of them are localized to subcellular compartments. Thus, to elucidate the numerous zinc-related cellular events, understanding those ZIP and ZnT functions is critical. This chapter describes advanced methods used in our laboratory to examine zinc mobilization by them. Specifically, genetic and molecular approaches using chicken DT40 cells deficient in multiple ZIPs and ZnTs are described. Moreover, procedures to evaluate zinc-related phenotypes caused by the impairment of zinc mobilization into and out of the secretory and endosomal-lysosomal compartments are also described. These methods should be useful in characterizing the roles of zinc in diverse cellular events including endosomal signaling. PMID:24359949

Kambe, Taiho

2014-01-01

436

Efficient organic solar cells based on phthalocyanines  

NASA Astrophysics Data System (ADS)

The primary goal of this thesis is to develop efficient organic solar cells by utilizing metallophthalocyanines (MPc) as donor materials. The role of centered metals in MPcs is discussed, and it is shown that a suitable choice of centered metals and device engineering lead to efficient MPc based solar cells. The effect of molecular packing of organic semiconductors on interfacial recombination at a donor/acceptor interface is also discussed. Organic solar cells based on planar metallophthalocyanines (MPc, M = Cu, Zn, Pd, Pc)/3,4,9,10-perylene tetracarboxylic bisbenzimidazole (PTCBI) are investigated. PdPc/PTCBI solar cells have a peak external quantum efficiency of 30.9%, which is almost two times larger than solar cells based on CuPc/PTCBI and ZnPc/PTCBI. External quantum efficiency measurement and optical modeling indicate that PdPc has longer exciton diffusion length than CuPc and ZnPc, leading to an enhanced efficiency. Device performance of organic solar cells consisting of ZnPc and fullerene (C60) can be enhanced by insertion of a N,N'-dihexyl-perylene-3,4,9,10-bis(dicarboximide) (PTCDI-C6) intermediate layer between fullerene and bathocuproine (BCP) exciton blocking layer. Insertion of the PTCDI-C6 layer between fullerene and BCP enhances an efficiency from 1.9 to 2.5%. The enhancement in device performances by insertion of PTCDI-C6 is attributed to reduction in device series resistances due to the promoted metal migration into BCP and optimized optical interference effects in multi-layered devices. Electron-hole pair recombination at donor/acceptor interfaces was discussed for PdPc/PTCDI derivatives solar cells with correlation of molecular packing in PTCDI derivatives. PTCDI with hexyl chains exhibits the highest charge separation efficiency among three PTCDI derivatives. Lastly, it is demonstrated that a power conversion efficiency of p-i-n type organic solar cells consisting of ZnPc and C60 can be enhanced by replacing ZnPc p-layer with PdPc. The optimized cell consisting of PdPc/ZnPc:C60/C60 exhibited an efficiency of 3.7%, while the cell with the device structure of ZnPc/ZnPc:C 60/C60 showed 3.2%. The enhancement in the efficiency is mainly attributed to increase in the short circuit current density, which is due to PdPc p-layer having longer exciton diffusion length than ZnPc.

Kim, Inho

437

Zinc chromate induces chromosome instability and DNA double strand breaks in human lung cells  

SciTech Connect

Hexavalent chromium Cr(VI) is a respiratory toxicant and carcinogen, with solubility playing an important role in its carcinogenic potential. Zinc chromate, a water insoluble or 'particulate' Cr(VI) compound, has been shown to be carcinogenic in epidemiology studies and to induce tumors in experimental animals, but its genotoxicity is poorly understood. Our study shows that zinc chromate induced concentration-dependent increases in cytotoxicity, chromosome damage and DNA double strand breaks in human lung cells. In response to zinc chromate-induced breaks, MRE11 expression was increased and ATM and ATR were phosphorylated, indicating that the DNA double strand break repair system was initiated in the cells. In addition, our data show that zinc chromate-induced double strand breaks were only observed in the G2/M phase population, with no significant amount of double strand breaks observed in G1 and S phase cells. These data will aid in understanding the mechanisms of zinc chromate toxicity and carcinogenesis.

Xie Hong; Holmes, Amie L.; Young, Jamie L.; Qin Qin [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., Portland, ME 04104-9300 (United States); Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth St., Portland, ME 04104-9300 (United States); Department of Applied Medical Science, University of Southern Maine (United States); Joyce, Kellie [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., Portland, ME 04104-9300 (United States); Pelsue, Stephen C. [Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth St., Portland, ME 04104-9300 (United States); Department of Applied Medical Science, University of Southern Maine (United States); Peng Cheng [Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth St., Portland, ME 04104-9300 (United States); Department of Mathematics and Statistics, University of Southern Maine (United States); Wise, Sandra S. [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., Portland, ME 04104-9300 (United States); Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth St., Portland, ME 04104-9300 (United States); Dept. of Applied Medical Science, Univ. of Southern Maine (United States); Jeevarajan, Antony S.; Wallace, William T.; Hammond, Dianne [Lyndon B. Johnson Space Center, Houston, TX 77058 (United States); Wise, John Pierce [Wise Lab. of Environmental and Genetic Toxicology, Univ. of Southern Maine, 96 Falmouth St., Portland, ME 04104-9300 (United States); Maine Center for Toxicology and Environmental Health, Univ. of Southern Maine, 96 Falmouth St., Portland, ME 04104-9300 (United States); Dept. of Applied Medical Science, Univ. of Southern Maine (United States)] E-mail: John.Wise@usm.maine.edu

2009-02-01

438

Zinc Chromate Induces Chromosome Instability and DNA Double Strand Breaks in Human Lung Cells  

PubMed Central

Hexavalent chromium Cr(VI) is a respiratory toxicant and carcinogen, with solubility playing an important role in its carcinogenic potential. Zinc chromate, a water insoluble or particulate Cr(VI) compound, has been shown to be carcinogenic in epidemiology studies and to induce tumors in experimental animals, but its genotoxicity is poorly understood. Our study shows that zinc chromate induced concentration-dependent increases in cytotoxicity, chromosome damage and DNA double strand breaks in human lung cells. In response to zinc chromate-induced breaks, MRE11 expression was increased and ATM and ATR were phosphorylated, indicating that the DNA double strand break repair system was initiated in the cells. In addition, our data show that zinc chromate-induced double strand breaks were only observed in the G2/M phase population, with no significant amount of double strand breaks observed in G1 and S phase cells. These data will aid in understanding the mechanisms of zinc chromate toxicity and carcinogenesis. PMID:19027772

Xie, Hong; Holmes, Amie L.; Young, Jamie L.; Qin, Qin; Joyce, Kellie; Pelsue, Stephen C.; Peng, Cheng; Wise, Sandra S.; Jeevarajan, Antony S.; Wallace, William T.; Hammond, Dianne; Wise, John Pierce

2014-01-01

439

Bioavailability of iron and zinc from multiple micronutrient fortified beverage premixes in Caco-2 cell model.  

PubMed

Iron and zinc deficiencies are the most prevalent nutrient deficiencies worldwide. They often coexist as the dietary factors, especially phytate, which impairs iron absorption also affects zinc absorption. Therefore, suitable strategies are required to control multiple micronutrient deficiencies in populations that subsist on high-phytate foods such as the whole wheat flour based Indian bread (chapatti). The objective of the study, therefore, was to test the bioavailability of iron and zinc in 2 multiple micronutrient beverage premixes in the absence and presence of?chapatti. The premix-1 contained iron, zinc, and vitamin A while premix-2 contained all micronutrients in premix-1, plus folic acid and ascorbic acid. Ferritin induction and (65)Zn uptake were assessed using coupled in vitro digestion/Caco-2 cell line model as the surrogate markers of iron and zinc bioavailability, respectively. The results show that iron bioavailability from premixes-1 and 2 was similar in the absence of?chapatti. However, premix-2 showed significantly higher iron bioavailability compared to premix-1 in the presence of?chapatti. In contrast, the zinc uptake was similar from both premixes-1 and 2 in the absence or presence of?chapatti. These results suggest that both the premixes provide bioavailable minerals, but pr