Note: This page contains sample records for the topic zinc phosphide solar cells from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

Thin film cadmium telluride and zinc phosphide solar cells  

NASA Astrophysics Data System (ADS)

The deposition of cadmium telluride films by direct combination of the cadmium and tellurium vapor on foreign substrates is described. Nearly stoichiometric p-type cadmium telluride films and arsenic-doped p-type films were prepared reproducibly. Major efforts were directed to the deposition and characterization of heterojunction window materials, indium tin oxide, fluorine-doped tin oxide, cadmium oxide, and zinc oxide. A number of heterojunction solar cells were prepared, and the best thin-film ITO/CdTe solar cells had an AMI efficiency of about 7.2%. Zinc phosphide films were deposited on W/steel substrated by the reaction of zinc and phosphine in a hydrogen flow. Films without intentional doping had an electrical resistivity on the order of 10(6) ohm-cm, and this resistivity may be reduced to about 5 x 10(4) ohm-cm by adding hydrogen chloride or hydrogen bromide to the reaction mixture. Lower resistivity films are deposited by adding a controlled amount of silver nitrate solution on to the substrate surface. Major efforts are directed to the deposition of low-resistivity zinc selenide to prepare ZnSe/An3P2 heterojunction thin-film solar cells. The zinc selenide films deposited by vaccum evaporation and chemical vapor deposition techniques are all of high resistivity.

Chu, T.

1984-10-01

2

Thin film cadmium telluride and zinc phosphide solar cells  

SciTech Connect

This report describes research performed from June 1982 to October 1983 on the deposition of cadmium telluride films by direct combination of the cadmium and tellurium vapor on foreign substrates. Nearly stoichiometric p-type cadmium telluride films and arsenic-doped p-type films have been prepared reproducibly. Major efforts were directed to the deposition and characterization of heterojunction window materials, indium tin oxide, fluorine-doped tin oxide, cadmium oxide, and zinc oxide. A number of heterojunction solar cells were prepared, and the best thin-film ITO/CdTe solar cells had an AMl efficiency of about 7.2%. Zinc phosphide films were deposited on W/steel substrates by the reaction of zinc and phosphine in a hydrogen flow. Films without intentional doping had an electrical resistivity on the order of 10/sup 6/ ohm-cm, and this resistivity may be reduced to about 5 x 10/sup 4/ ohm-cm by adding hydrogen chloride or hydrogen bromide to the reaction mixture. Lower resistivity films were deposited by adding a controlled amount of silver nitrate solution on to the substrate surface. Major efforts were directed to the deposition of low-resistivity zinc selenide in order to prepare ZnSe/An/sub 3/P/sub 2/ heterojunction thin-film solar cells. However, zinc selenide films deposited by vacuum evaporation and chemical vapor deposition techniques were all of high resistivity.

Chu, T.

1984-10-01

3

Indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

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

Weinberg, Irving

1991-01-01

4

High efficiency indium tin oxide\\/indium phosphide solar cells  

Microsoft Academic Search

Solar cells have been fabaricated by RF sputter depositing indium tin oxide onto single crystal p-type indium phosphide. Four different substrate doping densities have been used but in all cases the dopant was zinc and the wafers were (100) oriented. The optimum doping density from the range studied was 3 x 10 to the 16th per cu cm and devices

T. J. Coutts; S. Naseem

1985-01-01

5

RED Facts: Zinc Phosphide.  

National Technical Information Service (NTIS)

This fact sheet summarizes the information in the RED document for reregistration case 0026, zinc phosphide. Zinc phosphide is a rodenticide used to control gophers, mice, rats, lagomorphs (e.g. jack rabbits), prairie dogs, and squirrels.

1998-01-01

6

High efficiency indium tin oxide/indium phosphide solar cells  

NASA Astrophysics Data System (ADS)

Solar cells have been fabaricated by RF sputter depositing indium tin oxide onto single crystal p-type indium phosphide. Four different substrate doping densities have been used but in all cases the dopant was zinc and the wafers were (100) oriented. The optimum doping density from the range studied was 3 x 10 to the 16th per cu cm and devices based on such substrates have yielded total area efficiencies up to 16.2 percent using the air mass 1.5 spectrum normalized to 100 mW/sq cm, which correspond to active area efficiencies of 19.1 percent. A doping density less than the optimum yielded devices with excessive series resistance. Higher doping densities led to a marked loss of red response.

Coutts, T. J.; Naseem, S.

1985-01-01

7

Determination of series resistance of indium phosphide solar cells  

NASA Technical Reports Server (NTRS)

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

Jain, Raj K.; Weinberg, Irving

1991-01-01

8

Status of indium phosphide solar cell development at Spire  

NASA Technical Reports Server (NTRS)

On-going development of indium phosphide solar cells for space applications is presented. The development is being carried out with a view towards both high conversion efficiency and simplicity of manufacture. The cell designs comprise the ion-implanted cell, the indium tin oxide top contact cell, and the epitaxial cell grown by metal organic chemical vapor deposition. Modelling data on the limit to the efficiency are presented and comparison is made to measured performance data.

Spitzer, M. B.; Keavney, C. J.; Vernon, S. M.

1987-01-01

9

Indium phosphide solar cells for laser power beaming applications  

NASA Technical Reports Server (NTRS)

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

Jain, Raj K.; Landis, Geoffrey A.

1992-01-01

10

Indium phosphide solar cells made by ion implantation  

NASA Astrophysics Data System (ADS)

High-efficiency indium phosphide solar cells of the shallow homojunction type have been made using ion implantation to form the emitter layer. An anneal in phosphine was used to recover the implant damage. The cells show a 5 percent higher short-circuit current than cells with a similar base but with an epitaxial emitter. The open-circuit voltage is slightly higher than that of the epitaxial cells, and the fill factor slightly lower. Conversion efficiency of 18.8 percent (air mass zero, total area) has been achieved; this is the highest thus far reported for an InP cell.

Keavney, C. J.; Spitzer, M. B.

1988-04-01

11

Recent developments in indium phosphide space solar cell research  

NASA Technical Reports Server (NTRS)

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

Brinker, David J.; Weinberg, Irving

1987-01-01

12

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

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

13

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

14

Progress in indium phosphide solar cell research  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

15

Optimal design study of high efficiency indium phosphide space solar cells  

NASA Technical Reports Server (NTRS)

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

Jain, Raj K.; Flood, Dennis J.

1990-01-01

16

Potential for Use of Indium Phosphide Solar Cells in the Space Radiation Environment.  

National Technical Information Service (NTIS)

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 foun...

I. Weinberg C. K. Swartz R. E. Hart

1985-01-01

17

a Fundamental Study of N-Indium Tin P-Indium Phosphide Solar Cells  

Microsoft Academic Search

Indium phosphide (InP) is an important technical material in opto-electronics and has recently shown potential for space-borne solar cells because of its high radiation resistance. ITO\\/InP solar cells with world-record efficiencies of almost 19% (global 1000 W m^{-2 } measured under standard condition: T = 25 ^circC) and almost equal radiation resistance have been made, corresponding to an efficiency of

Xiaonan S. Li

1990-01-01

18

High-efficiency indium tin oxide\\/indium phosphide solar cells  

Microsoft Academic Search

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

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

1989-01-01

19

Abdominal imaging in zinc phosphide poisoning.  

PubMed

Radiography has been proved to be a good diagnostic tool in visualization of many radiopaque xenobiotics in clinical toxicology. Zinc is a potentially radiopaque material which is a constituent of the zinc phosphide (ZN2P3) rodenticide. We report two cases of zinc phosphide poisoning with positive abdominal X-rays in whom the diagnosis was confirmed by abdominal imaging. Positive abdominal imaging was an indication for aggressive management; however, aggressive treatment was not lifesaving in one of them. We aim to emphasize the diagnostic value of abdominal X-rays in zinc phosphide-poisoned patients. We also would like to suggest that zinc phosphide (ZP)-poisoned patients with positive X-rays have more chance to become unstable even if they are symptom free on presentation and should be more aggressively managed. PMID:24477450

Hassanian-Moghaddam, Hossein; Shahnazi, Makhtoom; Zamani, Nasim; Bahrami-Motlagh, Hooman

2014-06-01

20

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

21

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

22

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

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

23

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

24

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

25

Reregistration Eligibility Decision (RED): Zinc Phosphide (Includes RED Facts: Zinc Phosphide Fact Sheet).  

National Technical Information Service (NTIS)

This document presents the Agency's decision regarding the reregistration eligibility of the registered uses of zinc phosphide, including the risk to infants and children for any potential dietary, drinking water, dermal or oral exposures, and cumulative ...

1998-01-01

26

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

Microsoft Academic Search

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

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

1993-01-01

27

Indium Phosphide/Cadmium Sulfide Thin-Film Terrestrial Solar Cells. Quarterly Report No. 4, July 1--September 14, 1977.  

National Technical Information Service (NTIS)

Indium phosphide/cadmium sulfide solar cells with AM2 efficiencies up to 7% were prepared by the deposition of CdS on single crystals of InP. When an intermediate layer of n-type InP was deposited by the planar reactive deposition (PRD) technique, 3% effi...

K. Zanio L. Fraas

1977-01-01

28

A review of indium phosphide space solar cell fabrication technology  

Microsoft Academic Search

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

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

1990-01-01

29

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

30

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

31

Annealing of defect sites in radiation damaged indium phosphide solar cells through laser illumination. Master`s thesis  

SciTech Connect

This thesis reports the results of a laser annealing technique used to remove defect sites from radiation damaged indium phosphide diffused junction solar cells. This involves the illumination of damaged solar cells with a continuous wave laser to produce a moderate heating and a large forward-biased current. The InP cells were irradiated with 27 MeV electrons to a given fluence, and tested for degradation. Light from an argon laser was used to illuminate each cell with an irradiance of 2.5 W/sq cm, producing a current density 7 to 10 times larger than under AMO conditions. Cells were annealed at 48.5 deg C, 60 deg C, and 75 deg C for periods of 15 to 60 minutes, and cooled to 25 deg C for power recovery determination. Annealing at 48.5 deg C resulted in a recovery of 17 to 18% of the power lost due to irradiation, and annealing cells at 60 deg C produced a recovery of 43 to 48%. A single test of the technique at 75 deg C produced a net recovery of only 21% of the power lost. These results indicate that significant power recovery results from the annealing of defects within InP solar cells. Continuing research should involve the repeating of the test at 75 deg C, and irradiations with electrons or protons of energies expected in the space environment.

Chase, C.T.

1995-12-01

32

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

33

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

34

Responses of Siberian ferrets to secondary zinc phosphide poisoning  

USGS Publications Warehouse

The hazard of operational-type applications of zinc phosphide (Zn3P2) on a species closely related to the black-footed ferret (Mustela nigripes), was evaluated by feeding 16 Siberian ferrets (M. eversmanni) rats that had been killed by consumption of 2% zinc phosphide treated bait or by an oral dose of 40, 80, or 160 mg of Zn3P2. All ferrets accepted rats and a single emesis by each of 3 ferrets was the only evidence of acute intoxication. All ferrets learned to avoid eating gastrointestinal tracts of the rats. Subacute zinc phosphide toxicity in the ferrets was indicated by significant decreases (18-48%) in hemoglobin, increases of 35-91 % in serum iron, and elevated levels of serum globulin, cholesterol, and triglycerides. Hemoglobin/iron, urea nitrogen/creatinine, and albumin/globulin ratios also were altered by the treatments. This study demonstrated that Siberian ferrets, or other species with a sensitive emetic reflex, are afforded a degree of protection from acute zinc phosphide poisoning due to its emetic action. The importance of toxicity associated with possible respiratory, liver, and kidney damage indicated by altered blood chemistries is not known.

Hill, E.F.; Carpenter, J.W.

1982-01-01

35

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

NASA Technical Reports Server (NTRS)

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

Goradia, Chandra; Thesling, William; Weinberg, Irving

1991-01-01

36

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

37

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

NASA Technical Reports Server (NTRS)

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

Clark, Ralph O.

1992-01-01

38

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

39

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

NASA Technical Reports Server (NTRS)

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

Summers, Geoffrey P.

1996-01-01

40

Indium Phosphide/Cadmium Sulfide Thin-Film Solar Cells. Final Report, June 1980-June 1981.  

National Technical Information Service (NTIS)

Thin-films of InP were grown on recrystallized CdS (RXCdS) and InP by planar reactive deposition for the purpose of determining the factors which limit the development of InP/RXCdS thin-film solar cells. InP films were grown on RXCdS at substrate temperat...

K. Zanio

1981-01-01

41

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

NASA Technical Reports Server (NTRS)

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

Goradia, Chandra; Thesling, William; Weinberg, Irving

1991-01-01

42

Indium phosphide\\/cadmium sulfide thin-film solar cells. Quarterly report, July-October 1980  

Microsoft Academic Search

InP thin films were deposited by planar reactive deposition on recrystallized CdS (RXCdS) and semi-insulating (100) InP substrates and evaluated as potential layers for an all-thin-film solar cell. One objective of this period was to grow InP on RXCdS at a substrate temperature which is high enough to permit the growth of p-type material but yet low enough to permit

Zanio

1981-01-01

43

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

44

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

45

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

NASA Astrophysics Data System (ADS)

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

Parrott, J. E.; Potts, A.

46

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

NASA Technical Reports Server (NTRS)

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

Goradia, Chandra; Thesling, William; Weinberg, Irving

1991-01-01

47

Indium phosphide/cadmium sulfide thin-film solar cells. Quarterly report, July-October 1980  

SciTech Connect

InP thin films were deposited by planar reactive deposition on recrystallized CdS (RXCdS) and semi-insulating (100) InP substrates and evaluated as potential layers for an all-thin-film solar cell. One objective of this period was to grow InP on RXCdS at a substrate temperature which is high enough to permit the growth of p-type material but yet low enough to permit the epitaxial growth of large grains. Films prepared on RXCdS at approximately 330/sup 0/C contained a mixture of grains having both large and submicron lateral dimensions. Be-doped epitaxial films, deposited on semi-insulating InP at 330/sup 0/C, showed both n- and p-type behavior. Films prepared at higher temperatures with a freshly Be-charged indium source were p-type. However, at these temperatures, layers prepared after several runs with the same source were n-type. Analyses of the indium source and films were initiated to determine the cause of the transient doping.

Zanio, K.

1981-01-01

48

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

SciTech Connect

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

Boyer, L.L.

1996-06-01

49

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

50

Investigation on Zinc Sulphide Nanoparticles in Dye Sensitized Solar Cell  

NASA Astrophysics Data System (ADS)

Nanoparticles of zinc sulphide in cubic sphalerite phase are synthesized by aqueous chemical method. UV-Vis absorption spectrum of nano ZnS is blue shifted from the bulk by 50 nm and methyl blue sensitized nano ZnS shows a strong visible absorption at 600 nm. PL spectrum of methyl blue sensitized ZnS shows two broad emission at 402 nm and 510 nm which are compared with earlier investigations and discussed. The solar conversion efficiency (?) of this dye sensitized solar cell (DSSC) was found to have enhanced due to charge transfer from dye molecules.

Ragam, M.; Sankar, N.; Ramachandran, K.

2011-07-01

51

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

52

Gap/silicon Tandem Solar Cell with Extended Temperature Range  

NASA Technical Reports Server (NTRS)

A two-junction solar cell has a bottom solar cell junction of crystalline silicon, and a top solar cell junction of gallium phosphide. A three (or more) junction solar cell has bottom solar cell junctions of silicon, and a top solar cell junction of gallium phosphide. The resulting solar cells exhibit improved extended temperature operation.

Landis, Geoffrey A. (Inventor)

2006-01-01

53

Identification of phases in thin amorphous films of zinc phosphides  

SciTech Connect

Analysis of the experimental atomic radial distribution functions for thin amorphous films of zinc phosphides obtained by explosive laser sputtering has been performed within a fragmentary model. The experiment was carried out with an Emp-10a electron diffractometer in transmitted light at accelerating voltages of 50 and 75 kV. The films obtained by sputtering of {beta}-ZnP{sub 2} single crystals contained nanoparticles of this phase. The films based on Zn{sub 3}P{sub 2} turned out to be two-phase and consisted of dispersed Zn{sub 3}P{sub 2} and {beta}-ZnP{sub 2} nanoparticles. The composition of the film obtained on the basis of {alpha}-ZnP{sub 2} corresponded neither to any one of the known phases in the Zn-P system nor to any mixture of these phases. Crystallization of films in a divergent electron beam confirmed the results of the phase analysis performed using the model atomic radial distribution functions.

Aleinikova, K. B.; Zinchenko, E. N., E-mail: zinchenko@phys.vsu.ru; Lesovoi, M. V. [Voronezh State University (Russian Federation)

2007-03-15

54

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

55

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

56

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

57

Diffusion redistribution of zinc during the doping of structurally inhomogeneous epitaxial layers of gallium phosphide  

NASA Astrophysics Data System (ADS)

The distribution of zinc established during its diffusion accompanying the doping of gallium phosphide layers in the course of epitaxial growth has been numerically simulated. The internal redistribution of zinc introduced in the presence of a structural macrodefect (in particular, screw dislocation) is treated according to the dissociative model of the interstitial-lattice site diffusion. This model assumes the existence of zinc ions in two states with different diffusion mobilities that actively interact with gallium vacancies. The results of an analysis of solutions of a nonlinear boundary-value problem demonstrate the existence of sharply inhomogeneous distributions of the zinc ion concentration, which explain some experimentally observed anomalies in the reverse current of zinc-doped epitaxial GaP-based p-tn junctions.

Panyutin, E. A.

2009-07-01

58

Zinc oxide nanowire arrays for silicon core/shell solar cells.  

PubMed

The optics of core / shell nanowire solar cells was investigated. The optical wave propagation was studied by finite difference time domain simulations using realistic interface morphologies. The interface morphologies were determined by a 3D surface coverage algorithm, which provides a realistic film formation of amorphous silicon films on zinc oxide nanowire arrays. The influence of the nanowire dimensions on the interface morphology and light trapping was investigated and optimal dimensions of the zinc oxide nanowire were derived. PMID:24922370

Tamang, Asman; Pathirane, Minoli; Parsons, Rion; Schwarz, Miriam M; Iheanacho, Bright; Jovanov, Vladislav; Wagner, Veit; Wong, William S; Knipp, Dietmar

2014-05-01

59

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

National Technical Information Service (NTIS)

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 tellur...

T. L. Chu

1992-01-01

60

Porous copper zinc tin sulfide thin film as photocathode for double junction photoelectrochemical solar cells.  

PubMed

Porous copper zinc tin sulfide (CZTS) thin film was prepared via a solvothermal approach. Compared with conventional dye-sensitized solar cells (DSSCs), double junction photoelectrochemical cells using dye-sensitized n-type TiO(2) (DS-TiO(2)) as the photoanode and porous p-type CZTS film as the photocathode shows an increased short circuit current, external quantum efficiency and power conversion efficiency. PMID:22322239

Dai, Pengcheng; Zhang, Guan; Chen, Yuncheng; Jiang, Hechun; Feng, Zhenyu; Lin, Zhaojun; Zhan, Jinhua

2012-03-21

61

Small molecule solar cells based on a series of water-soluble zinc phthalocyanine donors.  

PubMed

Organic solar cells based on a series of water-soluble zinc phthalocyanines (wsZnPc) with varying numbers of sulfonate peripheral substituents and a C60 donor have been fabricated and characterised. We find that the number of substituents affects both the V(oc) and J(sc) of the devices, with the disulfonated wsZnPc devices performing best. PMID:22433974

Ryan, James William; Anaya-Plaza, Eduardo; de la Escosura, Andrés; Torres, Tomas; Palomares, Emilio

2012-06-21

62

Solar-cell characteristics and interfacial chemistry of indium-tin-oxide\\/indium phosphide and indium-tin-oxide\\/gallium arsenide  

Microsoft Academic Search

The preparation of indium-tin-oxide (ITO)\\/p-InP and ITO\\/p-GaAs solar cells via ion-beam deposition, rf sputtering, and magnetron sputtering of ITO onto single-crystal InP and GaAs substrates is described. The properties of these solar cells are strongly affected by the fabrication conditions and are related to chemical modifications of the junctions. The solar power conversion efficiencies at air mass 2 of ITO\\/p-GaAs

K. J. Bachmann; H. Schreiber Jr.; W. R. Sinclair; P. H. Schmidt; F. A. Thiel; E. G. Spencer; G. Pasteur; W. L. Feldmann; K. Sreeharsha

1979-01-01

63

Investigation on Zinc Sulphide Nanoparticles in Dye Sensitized Solar Cell  

Microsoft Academic Search

Nanoparticles of zinc sulphide in cubic sphalerite phase are synthesized by aqueous chemical method. UV-Vis absorption spectrum of nano ZnS is blue shifted from the bulk by 50 nm and methyl blue sensitized nano ZnS shows a strong visible absorption at 600 nm. PL spectrum of methyl blue sensitized ZnS shows two broad emission at 402 nm and 510 nm

M. Ragam; N. Sankar; K. Ramachandran

2011-01-01

64

Computational screening of functionalized zinc porphyrins for dye sensitized solar cells.  

PubMed

An efficient dye sensitized solar cell (DSSC) is one possible solution to meet the world's rapidly increasing energy demands and associated climate challenges. This requires inexpensive and stable dyes with well-positioned frontier energy levels for maximal solar absorption, efficient charge separation, and high output voltage. Here we demonstrate an extensive computational screening of zinc porphyrins functionalized with electron donating side groups and electron accepting anchoring groups. The trends in frontier energy levels versus side groups are analyzed and a no-loss DSSC level alignment quality is estimated. Out of the initial 1029 molecules, we find around 50 candidates with level alignment qualities within 5% of the optimal limit. We show that the level alignment of five zinc porphyrin dyes which were recently used in DSSCs with high efficiencies can be further improved by simple side group substitutions. All frontier energy levels, gaps and level alignment quality values are stored in a database publicly available. PMID:24129651

Ornsø, Kristian B; Garcia-Lastra, Juan M; Thygesen, Kristian S

2013-11-28

65

A comparative field trial, conducted without pre-treatment census baiting, of the rodenticides zinc phosphide, thallium sulphate and gophacide against Rattus norvegicus.  

PubMed Central

The effectiveness of the single-dose poison treatments of farm rat infestations, analysed by comparing the weights of the post-treatment census bait takes in covariance with the weights of the prebait takes, showed that treatments with 2-5% zinc phosphide, 0-3% thallium sulphate or 0-3% gophacide were equally effective and significantly better than were treatments with 1% zinc phosphide or 0-1% thallium sulphate. The methodology and sensitivity of different analyses are also considered.

Rennison, B. D.

1976-01-01

66

10% conversion efficiency in thin film polycrystalline cadmium-zinc sulfide/copper sulfide solar cells  

NASA Astrophysics Data System (ADS)

Thin film cadmium-zinc sulfide/copper sulfide solar cells have been developed with conversion efficiencies greater than 10% in direct sunlight. The development of these cells was based on decreasing the electron affinity mismatch between the Cu2S and CdS and thereby raising the open-circuit voltage above that achievable with the standard CdS/Cu2S solar cell. The electron affinity of the CdS was reduced by the incorporation of Zn by the co-evaporation of CdS and ZnS. With improved preparation of Cd(1-x)Zn(x)S (with x between .1 and .2) films, and the same process that produced Cu2S/CdS cells with efficiencies in excess of 9%, the increased open-circuit voltage has led to efficiencies greater than 10%.

Hall, R. B.; Birkmire, R. W.; Phillips, J. E.; Meakin, J. D.

67

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

SciTech Connect

This report covers the first year 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 SnO{sub 2}/glass substrates by metal-organic chemical vapor deposition (MOCVD) by reacting dimethylcadmium (DMCd) with diisopropyltellurium (DITe) in H{sub 2}. 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 SnO{sub 2}/glass substrates, and ZnO/ZnTe heterojunctions were produced. Open-circuit voltages of 0.6--0.7 V were measured for ZnS/ZnTe heterojunctions. 14 refs., 21 figs., 3 tabs.

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

1989-10-01

68

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

NASA Astrophysics Data System (ADS)

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

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

1999-03-01

69

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

SciTech Connect

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

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

1998-10-28

70

Photoelectronic properties of zinc phosphide crystals, films, and heterojunctions. Quarterly progress report No. 6, July 1September 30, 1980  

Microsoft Academic Search

The purpose of this research program is to investigate the photoelectronic properties of zinc phosphide (ZnâPâ) in single crystal form, in thin-film form, and in heterojunctions in which ZnâPâ forms one of the elements. This research will be directed toward understanding the role of crystalline defects and impurities in ZnâPâ, the nature of the electronic charge transport in single crystal

Bube

1980-01-01

71

Advantages of using amorphous indium zinc oxide films for window layer in Cu(In,Ga)Se 2 solar cells  

Microsoft Academic Search

The advantages of using indium zinc oxide (IZO) films instead of conventional Ga-doped zinc oxide (ZnO:Ga) films for Cu(In,Ga)Se2 (CIGS) solar cells are described. The electrical properties of IZO are independent of film thickness. IZO films have higher mobility (30–40cm2\\/Vs) and lower resistivity (4–5×10?4?cm) compared to ZnO:Ga films deposited without intentional heating, because the number of grain boundaries in amorphous

Moe Warasawa; Akira Kaijo; Mutsumi Sugiyama

72

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

73

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

74

Synthesis of titanium dioxide and zinc oxide nanowires for excitonic solar cells  

NASA Astrophysics Data System (ADS)

Dye-sensitized, quantum-dot sensitized, quantum-dot, and hybrid organic/inorganic solar cells are promising excitonic photovoltaic devices for the generation of low cost, carbon free energy. Wide-band gap semiconductor nanowire photoanodes have the potential to increase the efficiencies of these excitonic solar cells. Controlling and tailoring the dimensions of the nanowires (i.e. nanowire height, diameter, and planar number density) for each solar cell type is important for efficiency improvement. Obtaining such control will require a detailed and fundamental understanding of the nanowire growth process. Towards this end, the synthesis of TiO2 and ZnO nanowire films in aqueous solutions was studied. Anatase TiO2 nanowire films were grown on flexible titanium foil substrates using a three step hydrothermal synthesis. First, the top surface of the titanium foil was transformed to Na2Ti2O 4(OH)2 nanotubes through hydrothermal oxidation in NaOH. Next, the Na2Ti2O4(OH)2 nanotubes were converted to H2Ti2O4(OH)2 nanotubes by ion exchange. Finally, the H2Ti2O 4(OH)2 nanotubes were converted to polycrystalline anatase nanowires through a topotactic transformation. The film morphology evolution, crystal structure transformations, and growth mechanism were examined in detail. Dye-sensitized solar cells (DSSCs) were assembled from these TiO 2 nanowire films. Transient photocurrent and photovoltage spectroscopies were used to measure the electron transport and recombination rates in these solar cells. Compared to TiO2 nanoparticle DSSCs the electron collection efficiency in the TiO2 nanowire DSSCs was increased due to decreased electron recombination. However, the electron transport in the nanowire DSSCs was similar to that of TiO2 nanoparticle DSSCs. The synthesis of ZnO nanowires from aqueous solutions of methenamine (HMT) and zinc nitrate hexahydrate on substrates was studied in detail. A ZnO nanowire growth mechanism was proposed which predicts that the precursor is a zinc-methenamine complex (Zn-HMT2+ and Zn-HMT-Zn 4+) which reacts at the hydroxyl terminated nanowire surface. This growth mechanism was supported by examining the growth with several experimental techniques, kinetic modeling, and thermodynamic calculations. In addition, the ZnO nanowire film growth, on ZnO seeded substrates, was found to be mass transport limited. This results in an inverse relationship between the nanowire planar number density and the height and diameter of the nanowires. By stirring the solution the growth rate is increased by approximately a factor of four.

Boercker, Janice Elaine

75

InP (Indium Phosphide): Into the future  

NASA Technical Reports Server (NTRS)

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

Brandhorst, Henry W., Jr.

1989-01-01

76

Mixed metal oxides for dye-sensitized solar cell using zinc titanium layered double hydroxide as precursor  

NASA Astrophysics Data System (ADS)

Mixed metal oxides (MMO) are always obtained from layered double hydroxide (LDH) by thermal decomposition. In the present work, a zinc titanium LDH with the zinc titanium molar ratio of 4.25 was prepared by urea method and ZnO-based mixed oxides were obtained by calcining at or over 500°C. The MMO was used as electrodes for dye sensitized solar cell (DSSC). The cells constructed by films of prepared composite materials using a N719 as dye were prepared. The efficiency values of these cells are 0.691%, 0.572% and 0.302% with MMO prepared at 500, 600 and 700°C, respectively.

Liu, Jianqiang; Qin, Yaowei; Zhang, Liangji; Xiao, Hongdi; Song, Jianye; Liu, Dehe; Leng, Mingzhe; Hou, Wanguo; Du, Na

2013-12-01

77

Zinc porphyrins with a pyridine-ring-anchoring group for dye-sensitized solar cells.  

PubMed

Anchoring groups are extremely important in controlling the performance of dye-sensitized solar cells (DSCs). The design and characterization of sensitizers with new anchoring groups, in particular non-carboxylic acid groups, has become a recent focus of DSC research. Herein, new donor-?-acceptor zinc-porphyrin dyes with a pyridine ring as an anchoring group have been designed and synthesized for applications in DSCs. Photophysical and electrochemical investigations demonstrated that the pyridine ring worked effectively as an anchoring group for the porphyrin sensitizers. DSCs that were based on these new porphyrins showed an overall power-conversion efficiency of about 4.0 % under full sunlight (AM 1.5G, 100 mW cm(-2)). PMID:23424179

Lu, Jianfeng; Xu, Xiaobao; Li, Zhihong; Cao, Kun; Cui, Jin; Zhang, Yibo; Shen, Yan; Li, Yi; Zhu, Jun; Dai, Songyuan; Chen, Wei; Cheng, Yibing; Wang, Mingkui

2013-05-01

78

Solution-processed zinc phosphide (?-Zn3P2) colloidal semiconducting nanocrystals for thin film photovoltaic applications.  

PubMed

Zinc phosphide (Zn3P2) is a promising earth-abundant material for thin film photovoltaic applications, due to strong optical absorption and near ideal band gap. In this work, crystalline zinc phosphide nanoparticles are synthesized using dimethylzinc and tri-n-octylphosphine as precursors. Transmission electron microscopy and X-ray diffraction data show that these nanoparticles have an average diameter of ?8 nm and adopt the crystalline structure of tetragonal ?-Zn3P2. The optical band gap is found to increase by 0.5 eV relative to bulk Zn3P2, while there is an asymmetric shift in the conduction and valence band levels. Utilizing layer-by-layer deposition of Zn3P2 nanoparticle films, heterojunction devices consisting of ITO/ZnO/Zn3P2/MoO3/Ag are fabricated and tested for photovoltaic performance. The devices are found to exhibit excellent rectification behavior (rectification ratio of 600) and strong photosensitivity (on/off ratio of ?10(2)). X-ray photoelectron spectroscopy and ultraviolet photoemission spectroscopy analyses reveal the presence of a thin 1.5 nm phosphorus shell passivating the surface of the Zn3P2 nanoparticles. This shell is believed to form during the nanoparticle synthesis. PMID:23952612

Luber, Erik J; Mobarok, Md Hosnay; Buriak, Jillian M

2013-09-24

79

Influence of dopant and polymeric matrix on Indium tin oxide\\/p-zinc phtalocyanine\\/n-Si hybrid solar cells  

Microsoft Academic Search

The present paper reports on the photovoltaic properties of zinc phthalocyanine (ZnPc) films with various dopants sandwiched between indium tin oxide (ITO) and n-type silicon substrate. The ZnPc films were realized by entrapping the molecules in a poly(methyl methacrylate) matrix upon stirring and heating the components in solution. For the ITO\\/p-ZnPc\\/n-Si sandwich structure solar cells with ZnPc doped with I2

Lung-Chien Chen; Chung-Chieh Wang; Chia-Bin Cheng

2009-01-01

80

Synthesis of titanium dioxide and zinc oxide nanowires for excitonic solar cells  

Microsoft Academic Search

Dye-sensitized, quantum-dot sensitized, quantum-dot, and hybrid organic\\/inorganic solar cells are promising excitonic photovoltaic devices for the generation of low cost, carbon free energy. Wide-band gap semiconductor nanowire photoanodes have the potential to increase the efficiencies of these excitonic solar cells. Controlling and tailoring the dimensions of the nanowires (i.e. nanowire height, diameter, and planar number density) for each solar cell

Janice Elaine Boercker

2009-01-01

81

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

82

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

PubMed

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

Guijarro, Néstor; Guillén, Elena; Lana-Villarreal, Teresa; Gómez, Roberto

2014-05-21

83

Effects of Transition Metal Dichalcogenide Molybdenum Disulfide Layer Formation in Copper--Zinc--Tin--Sulfur Solar Cells from Numerical Analysis  

NASA Astrophysics Data System (ADS)

This study demonstrates the effects of transition metal dichalcogenide, MoS2 layer formation in between the copper--zinc--tin--sulphide (CZTS) absorber layer and Mo back contact from theoretical study and numerical modeling. The objective of this study is to elucidate the effects of n or p type MoS2 on the overall CZTS solar cell performance. Energy band line-up of Mo/MoS2/CZTS interface is analyzed to elucidate the interface properties. It is found out that p-MoS2 layer in CZTS solar cell induces the same adventitious effect as p-MoSe2 in CIGS solar cell. However, n-MoS2 layer has detrimental effect on the CZTS solar cell by creating an additional back contact diode with p-CZTS layer and an ohmic contact with Mo layer. Thickness, bandgap energy and carrier concentration of n-MoS2 all have been varied in the numerical simulation to observe its effects on the cell performance parameters. The results from numerical simulation show that MoS2 layer as thin as 50 nm is sufficient enough to induce adverse effect on the solar cell performance. This could be caused by the increase in series resistance of the solar cell as n-type MoS2 would inhibit hole current into Mo back contact due to the hole barrier between n-type MoS2 and Mo back contact. The increase in MoS2 bandgap and carrier concentration also results in detrimental effect to the performance of the cell mainly due to the possibility of electrons to drift towards the back contact and recombine.

Chelvanathan, Puvaneswaran; Hossain, Mohammad Istiaque; Husna, Jamilah; Alghoul, Mohammad; Sopian, Kamaruzzaman; Amin, Nowshad

2012-10-01

84

Photoelectronic properties of zinc phosphide crystals, films, and heterojunctions. Quarterly progress report No. 13 for the period April 1June 30, 1982  

Microsoft Academic Search

The research on zinc phosphides is summarized and includes: ZnâPâ materials preparation; electrical characterization of ZnâPâ crystals; characterization by low temperature photoluminescence, photoconductivity, Auger electron spectroscopy, and transmission electron microscopy; investigation of ZnâPâ based devices; and ZnâPâ films grown by close spaced vapor transport. An approach to future research on ZnâPâ is summarized and includes: chemical vapor transport growth with

Bube

1982-01-01

85

The kinetics of oxidative alcoholysis of zinc phosphide in the presence of oxygen and the FeCl3-I2 mixed catalyst in solution in butanol  

NASA Astrophysics Data System (ADS)

The oxidative alkoxylation of zinc phosphide to tributyl phosphate occurred at a high rate and with high selectivity in a solution of FeCl3-I2 in butanol at 50-70°C. The kinetic characteristics and optimum conditions of the process were determined. The experimental and literature data were used to identify key stages of the formation of tributyl phosphate in the presence of the mixed catalytic system.

Ibraimova, Zh. U.; Polimbetova, G. S.; Aleshkova, M. M.; Borangazieva, A. K.

2009-05-01

86

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

PubMed

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

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

2014-12-10

87

Oxide Solar Cells Fabricated Using Zinc Oxide and Plasma-Oxidized Cuprous Oxide  

NASA Astrophysics Data System (ADS)

Oxide heterojunction solar cells composed of an n-type Al-doped ZnO (AZO) thin film on the surfaces of p-type Cu2O films were fabricated. The Cu2O films of about 0.34 to 1.67 ?m thickness were grown by partial oxidation of a Cu sheet using microwave plasma. The AZO film of 400 nm thickness was deposited by magnetron sputtering. Energy conversion efficiencies of 0.12 to 0.30% were obtained in AZO/Cu2O cells under AM1.5 solar illumination.

Chan, Yi-Ming; Wu, Ya-Ting; Jou, Shyankay

2012-12-01

88

Development of Novel Al-Doped Zinc Oxide Films Fabricated on Etched Glass and Their Application to Solar Cells  

NASA Astrophysics Data System (ADS)

We have successfully developed novel aluminum-doped zinc oxide (AZO-X) films with a high haze ratio by the combined use of an etched glass substrate and wet-etched AZO-X films. The effects of the use of an etched glass substrate and wet-chemical etching on the properties of AZO-X films were investigated. The texture size and rms roughness of these films largely increased with glass surface roughening. Post-treatment using wet chemical etching slightly increased the texture size and rms roughness. The etched glass approach has been found to be a promising method for achieving an AZO-coated glass substrate with a high haze ratio. Using high-haze ratio AZO-X films as the front transparent conductive oxide (TCO) layers in solar cells, we improved the quantum efficiency (QE) of these solar cells particularly in the long-wavelength region. Thus, the AZO-X films deposited on etched glass have a high potential for use as front TCO layers in silicon-based thin-film solar cells.

Hongsingthong, Aswin; Aino, Akehiro; Sichanugrist, Porponth; Konagai, Makoto; Kuramochi, Hideto; Akiike, Ryo; Iigusa, Hitoshi; Utsumi, Kentaro; Shibutami, Tetsuo

2012-10-01

89

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

90

Solar-Thermal Decomposition of Zinc Sulfate.  

National Technical Information Service (NTIS)

Experimental decomposition of zinc sulfate in a rotary kiln which was heated in the White Sands Solar Furnace is described. The main findings of this research are: The zinc sulfate decomposed after 1 to 5 minutes of solar exposure when (a) the front therm...

P. K. Shell R. Ruiz C. M. Yu

1983-01-01

91

High efficiency and high photo-stability zinc-phthalocyanine based planar heterojunction solar cells with a double interfacial layer  

NASA Astrophysics Data System (ADS)

The use of CuI and MoO3 as a double interfacial layer between indium tin oxide (ITO) and a zinc phthalocyanine (ZnPc) layer improves the power conversion efficiency (?p) and the photo-stability at the same time in ZnPc based solar cells. Insertion of CuI without MoO3 increased ?p more than 2 times to 3.3%. However, the photo-stability is lowered even further due to diffusion of Cu. Insertion of the MoO3 layer between the ITO and CuI prevents the diffusion of Cu under UV illumination to achieve the improved photo-stability and ?p.

Kim, Tae-Min; Whan Kim, Ji; Shim, Hyun-Sub; Kim, Jang-Joo

2012-09-01

92

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

PubMed

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

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

2013-12-11

93

Zinc oxide nanostructures for applications as ethanol sensors and dye-sensitized solar cells  

Microsoft Academic Search

ZnO nanostructures were prepared by thermal oxidation technique for applying as ethanol sensors and dye-sensitized solar cells. To improve sensitivity of the sensor based on ZnO nanostructures, gold doping was performed in ZnO nanostructures. Gold-doped with 0%, 5%, and 10% by weight were investigated. The improvement of sensor sensitivity toward ethanol due to gold doping was observed at entire operating

Supab Choopun; Auttasit Tubtimtae; Theerapong Santhaveesuk; Sanpet Nilphai; Ekasiddh Wongrat; Niyom Hongsith

2009-01-01

94

Electrochemically deposited zinc oxide for light trapping in thin film silicon solar cell  

Microsoft Academic Search

Electrochemically deposited ZnO films which have the appropriate texture surface for light trapping effect in solar cells are presented. A voltage was applied between anodes and Ag-coated-stainless steel substrate as a cathode in the heated aqueous solution of Zn(NO\\/sub 3\\/)\\/sub 2\\/ and ZnO films were formed on the substrate. The specular-and-diffuse and diffuse reflectance at 800nm wavelength were 94.3% and

N. Toyama; R. Hayashi; Y. Sonoda; M. Iwata; Y. Miyamoto; H. Otoshi; K. Saito; K. Ogawa

2003-01-01

95

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

96

Solution-processable zinc oxide for the polymer solar cell based on P3HT:PCBM.  

PubMed

The device performance of polymer solar cells with zinc oxide (ZnO) nanoparticles inserted as an electron injection layer between the poly(3-hexylthiopene) (P3HT):phenyl-C60-butyric acid methyl ester (PCBM) active layer and the Al electrode was studied. The polymer solar cell consists of molybdenum-oxide (MoO3) as a hole injection layer, P3HT:PCBM bulk heterojunction as an active layer, and ZnO NPs as an electron injection layer. The ZnO layer was formed from a precursor solution on the top part of the P3HT:PCBM film (1:0.8 weight ratio) via sol-gel spin-coating, and was annealed at a low temperature (150 degrees C). The crystallinity, the atomic ratio of Zn and O, the absorption spectra, and the surface morphology of the ZnO thin films were studied. The device with a ZnO layer showed 9-11% higher J(SC) and 8-9% higher PCE compared to the devices without a ZnO layer. These improved device properties are attributed to the efficient electron extraction and the decreased reflectivity owing to the use of a ZnO layer. PMID:22121646

Kim, Jun Young; Noh, Seunguk; Lee, Donggu; Nayak, Pradipta K; Hong, Yongtaek; Lee, Changhee

2011-07-01

97

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

98

Phase separation analysis of bulk heterojunctions in small-molecule organic solar cells using zinc-phthalocyanine and C60  

NASA Astrophysics Data System (ADS)

To achieve efficient organic solar cells, donor and acceptor molecules are mixed in the photoactive layer to form a so-called bulk heterojunction. Due to molecular interactions, a certain degree of phase separation between donor and acceptor domains arises, which is necessary to achieve efficient charge extraction within the absorber layer. However, the mechanism that induces the phase separation is not fully understood and gaining detailed information about the molecular arrangement within these blend layers is quite challenging. We show that grazing incidence x-ray diffraction, combined with variable angle spectroscopic ellipsometry is a suitable way to investigate the molecular structure of blend layers in detail, consisting of a mixture of zinc-phthalocyanine (ZnPc) and C60. The degree of phase separation within the blend layer is influenced by substrate heating during the co-evaporation of ZnPc and C60 and by a variation of the mixing ratio. The effect of different blend layer morphologies on optical and electrical device performance is investigated by solar cell characterization and mobility measurements. We find that the molecular arrangement of C60 provides the essential driving force for efficient phase separation. Whereas spherical C60 molecules are able to form crystalline domains when deposited at elevated substrate temperatures, no ZnPc crystallites are observed, although the planar ZnPc molecules are not randomly oriented but standing upright within its domains. Comparing specular and grazing incidence x-ray diffraction, we find that only the latter method is able to detect nanocrystalline C60 in thin films due to its polycrystalline nature and small sized nanocrystallites. Solar cell measurements show an increase in fill factor and external quantum efficiency signal for blends with enhanced phase separation, induced by higher substrate temperatures. However, grazing incidence x-ray diffraction measurements reveal that ZnPc and C60 already form separate domains in unheated ZnPc:C60 blends, which provide fill factors close to 50% in the corresponding solar cells.

Schünemann, Christoph; Wynands, David; Wilde, Lutz; Hein, Moritz Philipp; Pfützner, Steffen; Elschner, Chris; Eichhorn, Klaus-Jochen; Leo, Karl; Riede, Moritz

2012-06-01

99

Ohmic contact for P type indium phosphide  

NASA Technical Reports Server (NTRS)

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

Hawrylo, Frank Z. (Inventor)

1980-01-01

100

Potassium-doped zinc oxide as photocathode material in dye-sensitized solar cells.  

PubMed

ZnO nanoparticles are doped with K and applied in p-type dye-sensitized solar cells (DSCs). The microstructure and dynamics of hole transportation and recombination are investigated. The morphology of the K-doped ZnO nanoparticles shows a homogeneous distribution with sizes in the range 30-40 nm. When applied in p-type DSCs in combination with C343 as sensitizer, the K-doped ZnO nanoparticles achieve a photovoltaic power conversion efficiency of 0.012 % at full-intensity sunlight. A further study on the device by transient photovoltage/photocurrent decay measurements shows that the K-doped ZnO nanoparticles have an appreciable hole diffusion coefficient (ca. 10(-6) cm(2) s(-1) ). Compared to the widely used p-type NiO nanoparticles, this advantage is crucial for further improving the efficiency of p-type DSCs. PMID:23509075

Bai, Jie; Xu, Xiaobao; Xu, Ling; Cui, Jin; Huang, Dekang; Chen, Wei; Cheng, Yibing; Shen, Yan; Wang, Mingkui

2013-04-01

101

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

102

Convergent synthesis of near-infrared absorbing, "push-pull", bisthiophene-substituted, zinc(II) phthalocyanines and their application in dye-sensitized solar cells.  

PubMed

Zinc(II) phthalocyanine dyes that contain triarylamine-terminated bisthiophene and hexylbisthiophene groups have been synthesized by a convergent approach by using carboxytriiodo-ZnPc as a precursor. Further transformation of the iodo groups by a Pd-catalyzed reaction allowed easy preparation of further extended ?-conjugated carboxy-ZnPcs. These dyes have been used as sensitizers in dye-sensitized solar cells, which exhibit a panchromatic response and moderate overall efficiencies. PMID:22473900

Ince, Mine; Cardinali, François; Yum, Jun-Ho; Martínez-Díaz, M Victoria; Nazeeruddin, Mohammad K; Grätzel, Michael; Torres, Tomás

2012-05-14

103

The characteristics of chemical and heat stability properties of chromium–vanadium–aluminum co-doped zinc oxide films for dye-sensitized solar cells  

Microsoft Academic Search

Transparent conducting oxide thin films are used as front contact material for dye-sensitized solar cells. This study investigated the effects of chromium (Cr) and vanadium (V) contents on the chemical and heat stability properties of aluminum-doped zinc oxide (AZO) thin films using pulsed direct current magnetic sputtering on Corning 1737F glass substrates. The experimental results show that Cr and V

Y. C. Lin; C. H. Chang; C. H. Shen; P. W. Wang; Y. C. Lee

2010-01-01

104

Electrochemical deposition of zinc oxide films from non-aqueous solution: a new buffer\\/window process for thin film solar cells  

Microsoft Academic Search

Zinc oxide is a wide band gap semiconductor with wide application in thin film devices such as n-type window layers for thin film solar cells, piezoelectric and luminescent devices, and for catalytic applications. We have cathodically electrodeposited films of ZnO by reduction of dissolved oxygen in a non-aqueous solution (dimethylsulfoxide) containing a Zn salt. This method allows a large deposition

D. Gal; G Hodes; D Lincot; H.-W Schock

2000-01-01

105

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

106

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)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. PMID:23571086

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

2013-06-01

107

P/N Inp Solar Cells on Ge Wafers.  

National Technical Information Service (NTIS)

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 ...

S. Wojtczuk S. Vernon E. A. Burke

1994-01-01

108

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

PubMed

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

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

2012-09-01

109

Cost-Effective and Self-Textured Gallium-Doped Zinc Oxide Front Contacts for Hydrogenated Amorphous Silicon Thin-Film Solar Cells  

NASA Astrophysics Data System (ADS)

We adopt a economical and original method to fabricate self-textured gallium-doped zinc oxide (GZO) front contacts for hydrogenated amorphous silicon (a-Si:H) single-junction solar cells. This technique involves an atmospheric-pressure plasma jet (APPJ) and a dc sputtering process. The electro-optical characteristics of the textured GZO films are mainly controlled by the haze of organosilicon underlayers deposited by the APPJ. The films exhibit an average optical transmittance of about 80% and resistivity below 9.91× 10-4 ? cm. Moreover, compared with flat solar cells, textured cells fabricated on moderate GZO front contacts show 7.9 and 10.9% enhancements in conversion efficiency and short-circuit current density, respectively.

Yu, Shu-Hung; Ho, Po-Ching; Lee, Chia-Ling; Bi, Chien-Chung; Yeh, Chih-Hung; Chang, Chun-Yen

2013-02-01

110

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

NASA Astrophysics Data System (ADS)

Polycrystalline Cd(1-x)Zn(x)Te and Cd(1-x)Mn(x)Te films with a band gap of 1.7 eV were successfully grown on glass/SnO2/CdS substrates by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD), respectively. Polycrystalline Cd(1-x)Zn(x)Te films grown by MBE resulted in uniform composition and sharp interfaces. However, polycrystalline Cd(1-x)Mn(x)Te films grown by MOCVD showed nonuniform compositions and evidence of manganese accumulation at the Cd(1-x)Mn(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 percent. MBE-grown CdTe cells also produced 8 to 9 percent efficiencies. The standard CdTe process was not optimum for ternary films and resulted in a decrease in the band gap. Recent results indicate that CdCl2 + ZnCl2 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.

1990-10-01

111

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

112

Development of highly efficient thin film silicon solar cells on texture-etched zinc oxide-coated glass substrates  

Microsoft Academic Search

ZnO films prepared by magnetron sputtering on glass substrates and textured by post-deposition chemical etching are applied as substrates for p–i–n solar cells. Using both rf and dc sputtering, similar surface textures can be achieved upon etching. Excellent light trapping is demonstrated by high quantum efficiencies at long wavelengths for microcrystalline silicon solar cells. Applying an optimized microcrystalline\\/amorphous p-layer design,

J Müller; O Kluth; S Wieder; H Siekmann; G Schöpe; W Reetz; O Vetterl; D Lundszien; A Lambertz; F Finger; B Rech; H Wagner

2001-01-01

113

Electron and proton damage coefficients for heteroepitaxial InP solar cells  

Microsoft Academic Search

Indium phosphide solar cells are known to be significantly more radiation resistant than either gallium arsenide or silicon. Their growth by heteroepitaxy offers additional advantages over growth by homoepitaxy. InP cells have been grown on lower cost substrates and if heteroepitaxial cells are to be used in space power applications, their behavior under electron and proton irradiations has to be

R. K. Jain; I. Weinberg; D. J. Brinker; D. A. Scheiman; C. Vargas-Aburto; C. K. Swartz

1994-01-01

114

Efficient and ultraviolet durable inverted organic solar cells based on an aluminum-doped zinc oxide transparent cathode  

NASA Astrophysics Data System (ADS)

High performance inverted bulk heterojunction organic solar cells (OSCs), based on the blend of poly[[4,8-bis[(2-ethylhexyl)oxy] benzo [1,2-b:4,5-b'] dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl

Liu, Hanxiao; Wu, Zhenghui; Hu, Jianqiao; Song, Qunliang; Wu, Bo; Lam Tam, Hoi; Yang, Qingyi; Hong Choi, Wing; Zhu, Furong

2013-07-01

115

Effect of phosphides on the structure and properties of hypereutectic silumins  

Microsoft Academic Search

1.All the phosphides investigated except gallium and indium phosphides have a considerable modifying effect on the structure and properties of hypereutectic Silumins.2.Aluminum phosphide has the largest effect on these alloys.3.Modification with AIIIBV phosphides increases the microhardness of the primary silicon grains.4.If the operating characteristics of parts do not change with the addition of copper and zinc to hypereutectic Silumins at

V. G. Sap'yan; T. V. Sil'chenko

1974-01-01

116

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

117

High-efficiency cadmium and zinc telluride based thin-film solar cells: Annual report, June 1, 1987--May 31, 1988  

SciTech Connect

This report contains results of research on high-efficiency cadmium and zinc telluride based thin-film solar cells from June 1987 to May 1988. CdTe and CdZnTe and CdTe and CdMnTe films were grown on CdS/SnO/sub 2//glass substrates by molecular beam epitaxy and metal-organic chemical vapor deposition, respectively. As-grown films were characterized by x-ray diffraction, surface photovoltage spectroscopy, and infrared, Raman, and Auger electron spectroscopy, among others, for composition, bulk uniformity, thickness, and film and interface quality. Single-crystal films were grown simultaneously to understand the growth conditions of the polycrystalline films. Cell efficiencies ranging from 6.0% to 6.7% were achieved with the Cd/sub 0.95/Mn/sub 0.05/Te film employing the glass/SnO/sub 2//CdS/CdMnTe/ZnTe/Au front-wall solar cell structure. Cells fabricated by using CdZnTe films yielded efficiencies from 3.0% to 3.6%. 12 refs., 32 figs., 7 tabs.

Rohatgi, A.; Summers, C.J.; Erbil, A.; Sudharsanan, R.; Ringel. S.

1989-04-01

118

High-efficiency cadmium and zinc telluride based thin-film solar cells: Annual report, June 1, 1987--May 31, 1988  

SciTech Connect

This report contains results of research on high-efficiency cadmium and zinc telluride based thin-film solar cells from June 1987 to May 1988. CdTe and CdZnTe and CdTe and CdMnTe films were grown on CdS/SnO{sub 2}/glass substrates by molecular beam epitaxy and metal-organic chemical vapor deposition, respectively. As-grown films were characterized by x-ray diffraction, surface photovoltage spectroscopy, and infrared, Raman, and Auger electron spectroscopy, among others, for composition, bulk uniformity, thickness, and film and interface quality. Single-crystal films were grown simultaneously to understand the growth conditions of the polycrystalline films. Cell efficiencies ranging from 6.0% to 6.7% were achieved with the Cd{sub 0.95}Mn{sub 0.05}Te film employing the glass/SnO{sub 2}/CdS/CdMnTe/ZnTe/Au front-wall solar cell structure. Cells fabricated by using CdZnTe films yielded efficiencies from 3.0% to 3.6%. 12 refs., 32 figs., 7 tabs.

Rohatgi, A.; Summers, C.J.; Erbil, A.; Sudharsanan, R.; Ringel. S.

1989-04-01

119

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

120

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

PubMed

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

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

2013-01-01

121

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

122

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

123

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

NASA Astrophysics Data System (ADS)

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

Greene, Raymond G.

1995-01-01

124

Automatically activated, 300 ampere-hour silver-zinc cell  

NASA Technical Reports Server (NTRS)

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

Hennigan, T. J.

1972-01-01

125

Correlation of open-circuit voltage and energy levels in zinc-phthalocyanine: C60 bulk heterojunction solar cells with varied mixing ratio  

NASA Astrophysics Data System (ADS)

The maximum open-circuit voltage VOC of bulk-heterojunction solar cells is limited by the effective HOMO(donor)-LUMO(acceptor) gap of the photoactive absorber blend. We investigate blend layers comprising zinc-phthalocyanine (ZnPc) and the buckminster fullerene C60 with ultraviolet, x-ray, and inverse photoelectron spectroscopy. By varying the volume mixing ratio ZnPc:C60 from 6:1 to 1:6, we observe a linear increase of the HOMO(ZnPc)-LUMO(C60) gap by 0.25 eV. The trend in this gap correlates with the change in the charge transfer energy measured by Fourier-transform photocurrent spectroscopy as well as with the observed open-circuit voltage of solar cells containing ZnPc:C60 as the photoactive absorber layer. Furthermore, the morphology of different ZnPc:C60 blend layers is investigated by grazing-incidence x-ray diffraction. As physical origins for the changed energy levels, a suppressed crystallization of the C60 phase in the presence of donor molecules as well as concentration-dependent growth modes of the ZnPc phase are suggested.

Tietze, Max L.; Tress, Wolfgang; Pfützner, Steffen; Schünemann, Christoph; Burtone, Lorenzo; Riede, Moritz; Leo, Karl; Vandewal, Koen; Olthof, Selina; Schulz, Philip; Kahn, Antoine

2013-08-01

126

Indium phosphide\\/cadmium sulfide thin-film solar cells  

Microsoft Academic Search

Thin films and large grains of InP were epitaxially deposited on low cost recrystallized CdS (RXCdS) substrates at 280 C by planar reactive deposition. At 380 C, a 0.4 to 1.0 micrometer thick In-Cd-S transition layer between the InP and the RXCdS degrades the quality of the InP epitaxy. However, p-type InP films were prepared at this temperature by Be-doping

K. Zanio

1980-01-01

127

Solar cells  

NASA Astrophysics Data System (ADS)

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

Treble, F. C.

1980-11-01

128

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

129

Solar cell  

US Patent & Trademark Office Database

The invention relates to a solar cell that comprises a planar semiconductor substrate with a front and a back; a multitude of holes that interconnect the front and the back; and current-collecting electrical contacts that are exclusively arranged on the back. The front comprises highly doped regions and lightly doped regions of a first type such that in each case the holes are situated in a highly doped region or adjoin such a region. According to a first aspect of the invention, the highly doped regions are arranged locally around the holes. According to a second aspect of the invention, the front comprises at least one region without holes, and the highly doped regions comprise one region or several regions that extends/extend to the at least one hole-free region. The invention furthermore relates to methods for manufacturing such solar cells.

2010-12-14

130

Zinc  

MedlinePLUS

... viruses . The body also needs zinc to make proteins and DNA , the genetic material in all cells. ... colitis or Crohn's disease . These conditions can both decrease the amount of zinc that the body absorbs ...

131

The effect of post-annealing treatment on the characteristics of a dye-sensitized solar cell with an indium zinc tin oxide electrode  

NASA Astrophysics Data System (ADS)

Indium-saving transparent conductive oxide (TCO) thin films, i.e., zinc and tin co-doped indium oxide (IZTO) films, were investigated for dye-sensitized solar cell (DSSC) applications. The films were prepared by the radio-frequency (RF) magnetron sputtering method utilizing a ceramic target with a nominal composition equal to In0.6Zn0.2Sn0.2O1.5. The substrate temperature was changed from room temperature to 400 °C while the RF power and the argon gas pressure during deposition were kept constant. The photovoltaic conversion efficiencies of the DSSC samples made with IZTO electrodes were compared with the samples made with FTO electrodes. Values of approximately 6.81% and 4.74% were obtained for the DSSC samples with FTO and IZTO electrodes, respectively, when the firing process was carried out in air atmosphere during DSSC fabrication. However, with the addition of post-annealing in argon or a forming gas, efficiency values increased to 6.06% or 5.54%, respectively, for the DSSC sample with an IZTO electrode.

Ma, Hong Chan; Damisih; Putri, Maryane; Cheon, Jong Hoon; Kim, Jae Hong; Lee, Hee Young

2012-12-01

132

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

NASA Astrophysics Data System (ADS)

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

Bu, Ian Y. Y.

2013-12-01

133

Photoelectronic properties of zinc phosphide crystals, films, and heterojunctions. Quarterly progress report No. 12, January 1March 31, 1982  

Microsoft Academic Search

Antiphase domain boundaries and low-angle grain boundaries formed from pile up of dislocations are the two commonly observed defects in sublimation-grown ZnâPâ crystals by TEM. Except for these two types of defect, the crystals were of good quality and defect free. CdS\\/ZnâPâ heterojunctions were prepared by vacuum evaporation deposition of CdS films onto single crystal ZnâPâ. The cells were poor

R. H. Bube; F. C. Wang; S. Casey

1982-01-01

134

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

135

Zinc homeostasis in C6 glioma cells  

Microsoft Academic Search

Zinc homeostasis in mammalian cells is precisely regulated by cellular signal transduction mechanisms. The main result of\\u000a this study is the finding that modulators of phospholipase C (PLC) activity affect cellular zinc export. Two different PLC\\u000a inhibitors caused an increase of the total cellular zinc level whereas two different PLC activators caused a decrease. Furthermore,\\u000a both the inhibition of cyclic

Sven Jansen; Jürgen Arning; Detmar Beyersmann

2005-01-01

136

Indium phosphide, indium-gallium-arsenide and indium-gallium-antimonide based high efficiency multijunction photovoltaics for solar energy harvesting  

Microsoft Academic Search

Multijunction solar cells direct sunlight towards matched spectral sensitivity by splitting the spectrum into smaller slices. The main challenge in the photovoltaic industry is to make the modules more cost effective. The high efficiency multijunction photovoltaics have played a very significant role in reducing the cost through concentrator photovoltaic systems being implemented around the world. For example National Renewable Energy

Indranil Bhattacharya; Simon Y. Foo

2009-01-01

137

Tapered aluminum-doped vertical zinc oxide nanorod arrays as light coupling layer for solar energy applications  

Microsoft Academic Search

Tapered aluminum-doped vertical zinc oxide nanorod arrays have been prepared by using simple electrodeposition at 75°C from an aqueous solution of zinc nitrate and aluminum nitrate. Two substrates were used, i.e., copper indium gallium (di)selenide solar cells and a solar thermal absorber. The resulting nanorod arrays were of high optical quality, indicting their applicability as a light coupling layer via

Jie Chen; Hong Ye; Lorenz Aé; Yang Tang; David Kieven; Thorsten Rissom; Julia Neuendorf; Martha Ch. Lux-Steiner

2011-01-01

138

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

139

Zinc uptake by blood cells of rats in zinc deficiency and inflammation  

Microsoft Academic Search

In zinc deficiency, the function of leukocytes is impaired. However, the results of studies on the zinc concentration of blood\\u000a cells in zinc deficiency are conflicting, probably in part because of technical and analytical problems. The aim of this study\\u000a was to investigate, under standard conditions, the uptake of65Zn-labeled zinc by blood cells, taken from zinc-deficient rats and from rats

Ton H. J. Naber; Cornelis J. A. van den Hamer; Wim J. M. van den Broek; Jan H. M. van Tongeren

1992-01-01

140

Polymer solar cells  

Microsoft Academic Search

Recent progress in the development of polymer solar cells has improved power-conversion efficiencies from 3% to almost 9%. Based on semiconducting polymers, these solar cells are fabricated from solution-processing techniques and have unique prospects for achieving low-cost solar energy harvesting, owing to their material and manufacturing advantages. The potential applications of polymer solar cells are broad, ranging from flexible solar

Gang Li; Rui Zhu; Yang Yang

2012-01-01

141

Flexible Solar Cells.  

National Technical Information Service (NTIS)

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 Fi...

1994-01-01

142

Solar Photovoltaic Cells.  

ERIC Educational Resources Information Center

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

Mickey, Charles D.

1981-01-01

143

Solar Furnace Study of Zinc Sulfate Decomposition.  

National Technical Information Service (NTIS)

The objectives of this study are: to establish the applicability of solar central receivers to thermochemical cycles that can utilize solid sulfate decomposition as the high temperature step; to demonstrate the use of a rotating kiln that has been designe...

O. H. Krikorian P. K. Shell

1981-01-01

144

BIOCHEMISTRY: How Cells Control Zinc Homeostasis  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. The structure of a transport protein for divalent metal cations sheds light on how metal concentrations in the cell are regulated. Divalent metal cations are essential for all living cells. For example, Mg2+ stabilizes the phosphates in adenosine triphosphate (ATP), and Zn2+ is required for transcription, immune functions, and neurotransmission. On page 1746 of this issue, Lu and Fu report the structure of a zinc transport protein that elucidates how the zinc concentration of the cell is controlled.

Dietrich H. Nies (Martin-Luther-University Halle-Wittenberg;Institute for Microbiology)

2007-09-21

145

Fullerene derivative-doped zinc oxide nanofilm as the cathode of inverted polymer solar cells with low-bandgap polymer (PTB7-Th) for high performance.  

PubMed

Modification of a ZnO cathode by doping it with a hydroxyl-containing derivative - giving a ZnO-C60 cathode - provides a fullerene-derivative-rich surface and enhanced electron conduction. Inverted polymer solar cells with the ZnO-C60 cathode display markedly improved power conversion efficiency compared to those with a pristine ZnO cathode, especially when the active layer includes the low-bandgap polymer PTB7-Th. PMID:23939927

Liao, Sih-Hao; Jhuo, Hong-Jyun; Cheng, Yu-Shan; Chen, Show-An

2013-09-14

146

Uniform solar cells  

NASA Technical Reports Server (NTRS)

Solar cells used in radiation sensors can be efficiently matched by individual trimming. Strip of aluminized Mylar is used to adjust cell output to within required tolerances. Method is faster than individual selection of matched cells.

1976-01-01

147

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

148

Aluminium phosphide poisoning  

PubMed Central

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

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

2006-01-01

149

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

150

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

151

Solar Cells and Photovoltaics  

Microsoft Academic Search

Photovoltaic solar cells are gaining wide acceptance for producing clean, renewable electricity. This has been based on more than 40 years of research that has benefited from the revolution in silicon electronics and compound semiconductors in optoelectronics. This chapter gives an introduction into the basic science of photovoltaic solar cells and the challenge of extracting the maximum amount of electrical

Stuart Irvine

2007-01-01

152

Heterostructure solar cells  

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

153

Zinc deficiency and effects of zinc supplementation on sickle cell anemia subjects.  

PubMed

In this paper clinical similarities between sickle cell anemia patients and zinc deficient subjects, the latter as reported from the Middle East have been presented. Zinc levels in plasma, red cells, hair and neutrophils were decreased in our adult patients with SCA. The activities of certain zinc dependent enzymes such as plasma RNase, red cell carbonic anhydrase, leucocyte alkaline phosphatase, and deoxythymidine kinase activity in freshly synthesized collagen connective tissue were consistent with the concept that indeed zinc deficiency occurred in SCA patients. Zinc supplementation under controlled conditions showed that the SCA patients gained weight, their serum testosterone level increased and plasma ammonia level decreased. Finally, we also observed abnormal dark adaptation in some SCA patients which improved following zinc supplementation. Inasmuch as we have previously reported that the number of irreversible sickle cells decrease following zinc supplementation, we would like to suggest that zinc supplementation at earlier age may be benefical in preventing organ damage. In conclusion, zinc supplementation should be prescribed for patients with SCA, particularly if they show evidences for zinc deficiency. PMID:7291206

Prasad, A S

1981-01-01

154

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

155

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

PubMed

Engineered nanoparticles have been under increasing scrutiny in recent years. High aspect ratio nanoparticles such as carbon nanotubes and nanowires have raised safety concerns due to their geometrical similarity to asbestos fibers. III-V epitaxial semiconductor nanowires are expected to be utilized in devices such as LEDs and solar cells and will thus be available to the public. In addition, clean-room staff fabricating and characterizing the nanowires are at risk of exposure, emphasizing the importance of investigating their possible toxicity. Here we investigated the effects of gallium phosphide nanowires on the fruit fly Drosophila melanogaster. Drosophila larvae and/or adults were exposed to gallium phosphide nanowires by ingestion with food. The toxicity and tissue interaction of the nanowires was evaluated by investigating tissue distribution, activation of immune response, genome-wide gene expression, life span, fecundity and somatic mutation rates. Our results show that gallium phosphide nanowires applied through the diet are not taken up into Drosophila tissues, do not elicit a measurable immune response or changes in genome-wide gene expression and do not significantly affect life span or somatic mutation rate. PMID:23787695

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

2013-07-19

156

Solar cell and cell mount  

Microsoft Academic Search

A point contact solar device is described comprising: solar cell dice, each die comprising: a semiconductive layer in which are formed wells of p-conductivity type and n-conductivity type in an alternating pattern, the wells extending to a bottom surface of the semiconductive layer; an insulating layer formed on the bottom surface of the semiconductive layer and patterned to expose the

D. L. Peltzer; R. L. Bechtel; W. C. Ko; W. T. Liggett

1989-01-01

157

Amorphous silicon solar cells  

Microsoft Academic Search

Amorphous silicon solar cells have been fabricated in several different structures: heterojunctions, p-i-n junctions, and Schottky barrier devices. The procedures used in constructing the various solar cells are discussed, and their photovoltaic properties are compared. At present, the highest conversion efficiency (5.5 percent) has been obtained with a Schottky barrier cell, and this structure appears to offer the best promise

D. E. Carlson

1977-01-01

158

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

159

Dye Sensitized Solar Cells  

PubMed Central

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

Wei, Di

2010-01-01

160

Dye sensitized solar cells.  

PubMed

Dye sensitized solar cell (DSSC) is the only solar cell that can offer both the flexibility and transparency. Its efficiency is comparable to amorphous silicon solar cells but with a much lower cost. This review not only covers the fundamentals of DSSC but also the related cutting-edge research and its development for industrial applications. Most recent research topics on DSSC, for example, applications of nanostructured TiO(2), ZnO electrodes, ionic liquid electrolytes, carbon nanotubes, graphene and solid state DSSC have all been included and discussed. PMID:20480003

Wei, Di

2010-01-01

161

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

162

Zinc/air cell cathode  

NASA Astrophysics Data System (ADS)

This invention relates to a cathode for an air depolarized cell in which the hydrophobic catalytic cathode contains or in integrally drophobi catalytic cathode contains or is integrally coated with, on the surface adjacent the cell separator, an absorbent material such as the gelling material used in the anode. The absorbent material, integrated with the cathode surface, adheres the separator to the cathode thereby preventing delamination and provides an electrolyte reservoir for the hydrophobic cathode.

McEvoy, J. J.

1986-04-01

163

Quantum dot solar cells  

Microsoft Academic Search

Quantum dot (QD) solar cells have the potential to increase the maximum attainable thermodynamic conversion efficiency of solar photon conversion up to about 66% by utilizing hot photogenerated carriers to produce higher photovoltages or higher photocurrents. The former effect is based on miniband transport and collection of hot carriers in QD array photoelectrodes before they relax to the band edges

A. J Nozik

2002-01-01

164

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

165

Photovoltaic solar cell  

DOEpatents

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

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

2013-11-26

166

Conjugated Polymer Solar Cells.  

National Technical Information Service (NTIS)

This report results from a contract tasking Moscow State University as follows: Conjugated polymers are promising materials for many photonics applications, in particular, for photovoltaic and solar cell devices. This project will study the possibility to...

D. Y. Paraschuk

2006-01-01

167

Inside a Solar Cell  

NSDL National Science Digital Library

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

2010-10-06

168

Photoelectrochemical Solar Cells.  

ERIC Educational Resources Information Center

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

McDevitt, John T.

1984-01-01

169

Systems analysis of Mars solar electric propulsion vehicles  

Microsoft Academic Search

Mission performance, mass, initial power, and cost are determined for solar electric propulsion vehicles across a range of payload masses, reference powers, and mission trajectories. Thick radiation shielding is added to arrays using indium phosphide or III-V multijunction solar cells to reduce the damage incurred through the radiation belts. Special assessments of power management and distribution systems, atmospheric drag, and

J. M. Hickman; H. B. Curtis; B. H. Kenny; R. J. Sefcik

1990-01-01

170

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

171

Nanocrystalline electrochemical solar cells  

Microsoft Academic Search

Standard solar cells exploit the physics of semiconductors in which the energy of absorbed photons excites charge-carrier pairs which are subsequently separated by the influence of a solid state junction to provide a photovoltage. In the nanocrystalline electrochemical cell, the optical absorber is a dye monolayer which after photo-excitation injects electrons into a semiconductor substrate, with charge neutrality being restored

A. J. McEvoy; M. Gratzel; H. Wittkopf; D. Jestell; J. Benemann

1994-01-01

172

Inside a Solar Cell  

NSDL National Science Digital Library

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

Nova; Domain, Teachers'

173

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

174

Welded solar cell interconnection  

SciTech Connect

The welding of solar cell interconnects has received increased attention in recent years. Welding is used routinely in Europe and is being investigated seriously by several solar array fabricators in the United States. Most of this welding has been made using parallel gap resistive heating. Hughes Aircraft Company has chosen to investigate ultrasonic welding as an alternate bonding method. The results of this work and the manner in which ultrasonic welding differs from parallel gap welding or soldering is herein summarized.

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

1982-09-01

175

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

176

Long-term temperature effects on GaAs solar cells  

Microsoft Academic Search

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

J. H. Heinbockel; K. H. Hong

1979-01-01

177

Cadmium sulfide solar cells  

NASA Technical Reports Server (NTRS)

Development, fabrication and applications of CdS solar cells are reviewed in detail. The suitability of CdS cells for large solar panels and microcircuitry, and their low cost, are emphasized. Developments are reviewed by manufacturer-developer. Vapor phase deposition of thin-film solar cells, doping and co-evaporation, sputtering, chemical spray, and sintered layers are reviewed, in addition to spray deposition, monograin layer structures, and silk screening. Formation of junctions by electroplating, evaporation, brushing, CuCl dip, and chemiplating are discussed, along with counterelectrode fabrication, VPD film structures, the Cu2S barrier layer, and various photovoltaic effects (contact photovoltage, light intensity variation, optical enhancement), and various other CdS topics.

Stanley, A. G.

1975-01-01

178

Flexible dye solar cells  

Microsoft Academic Search

Strategies towards flexible solid state solar cells based on nanocrystalline titanium oxide and organic hole conductor were investigated. For the flexible cell geometry a metal foil was used as substrate and a semi-transparent gold layer as counter electrode which allows light transmission (back illumination). The device performance of solid state cells based on SnO2:F coated glass on the one hand

Nathalie Rossier-Iten; Toby B. Meyer; Jessica Krueger; Michael Graetzel

2004-01-01

179

Interdigitated back contact solar cells  

Microsoft Academic Search

The interdigitated back contact solar cell (IBC cell) was shown to possess a number of advantages for silicon solar cells, which operate at high concentration. A detailed discussion of the factors which need to be considered in the analysis of semiconducting devices which utilize heavily doped regions such as those which are found in solar cells in both the emitter

M. S. Lundstrom; R. J. Schwartz

1980-01-01

180

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

181

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

182

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

183

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...

184

Ion Implanted Silicon Solar Cells.  

National Technical Information Service (NTIS)

The theory of pn-junction silicon solar cells is thoroughly discussed including detailed deductions and calculations concerning the theoretical spectral response and the dark current in a solar cell with a back surface field. Ion implantation theory is re...

P. Balslev

1981-01-01

185

Flexible solar cells.  

PubMed

Thin-film flexible photovoltaics are paving the way to low-cost electricity. Organic, inorganic and organic-inorganic solar cells are deposited over flexible substrates by high-throughput (often roll-to-roll printing) technologies to afford lightweight, economic solar modules that can be integrated into, not installed on, various surfaces. Current conversion efficiencies under standard conditions are in the 3-15 % range, but in real applications the overall productivity is high. These new photovoltaic technologies are ready to provide cheap, clean electricity to the 2 billion people who lack access to the grid as well as to energy-eager companies and families in the developed world facing the increasing costs of electricity generated using fossil fuel resources. This Review focuses on recent achievements in the area of flexible solar cells, highlights the principles behind the main technologies, and discusses future challenges in this area. PMID:18979493

Pagliaro, Mario; Ciriminna, Rosaria; Palmisano, Giovanni

2008-01-01

186

Certain Chemical Properties of Indium Phosphide.  

National Technical Information Service (NTIS)

The rates of dissolution of indium phosphide in certain acids at various temperatures were determined. Etching agents are proposed for chemical polishing, finding dislocation pits, and also for detecting single-crystal nature of ingots of indium phosphide...

G. I. Markina O. Y. Gukov V. L. Gordin Y. A. Ugai

1971-01-01

187

Solar cell area considerations  

Microsoft Academic Search

The impact of extra current collection from beyond the apparent solar cell edge on photovoltaic conversion efficiency is discussed. A fixed-beam movable x-y translation stage laser scan system is shown which can quantitatively measure such effects, and two examples of output from the scanner are illustrated. The recommendation is made that care should be exercised when reporting the efficiency of

C. R. Osterwald; K. A. Emery

1983-01-01

188

NASA Facts, Solar Cells.  

ERIC Educational Resources Information Center

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

National Aeronautics and Space Administration, Washington, DC.

189

Amorphous semiconductor solar cell  

DOEpatents

A solar cell comprising a back electrical contact, amorphous silicon semiconductor base and junction layers and a top electrical contact includes in its manufacture the step of heat treating the physical junction between the base layer and junction layer to diffuse the dopant species at the physical junction into the base layer.

Dalal, Vikram L. (Newark, DE)

1981-01-01

190

Lateral superlattice solar cells.  

National Technical Information Service (NTIS)

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...

A. Mascarenhas Y. Zhang J. M. Millunchick R. D. Twesten E. D. Jones

1997-01-01

191

Cadmium telluride solar cells  

SciTech Connect

Cadmium telluride is the only II-VI compound that can readily be prepared in both n- and p-type forms. Since, in addition, its bandgap lies near the optimum for solar energy conversion, it is currently one of the leading contenders for thin film terrestrial solar energy conversion. CdTe based solar cells with an efficiency of greater than 10% have been prepared by a variety of techniques including homojunction formation, chemical vapor transport of CdS to form a CdS/CdTe junction, electron beam evaporation of indium-tin oxide to form an ITO/CdTe junction, by closespaced vapor transport of both CdS and CdTe to form a CdS/CdTe junction, and by sintered layer techniques resulting in an all thin film sintered layer cell. Cells with creditable efficiency have also been prepared by ordinary vacuum evaporation of a window material, by spray pyrolysis deposition of a window material, and by electrodeposition of thin layers. This paper surveys research on CdTe solar cells and indicates the significant materials and device parameters.

Bube, R.H.

1983-05-01

192

Advanced solar cell concepts1  

Microsoft Academic Search

In order to ensure the widespread use of solar photovoltaic technology for terrestrial applications, cost per unit watt must be significantly lower than 1$\\/Watt level. Material limitation of wafer based Si cell technology and efficiency limitation of thin-film solar cell technologies needs to overcome in order to achieve the above- mentioned cost goal. Thermodynamically solar cell efficiencies can be as

C. S. Solanki; G. Beaucarne

2007-01-01

193

Solar PV- How A Solar Cell Works  

NSDL National Science Digital Library

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

Levander, Alejandro

2011-03-03

194

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

PubMed

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

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

2014-06-28

195

High Efficiency Multijunction Solar Cells with Finely-Tuned Quantum Wells  

NASA Astrophysics Data System (ADS)

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

Varonides, Argyrios C.

196

Zinc oxyfluoride transparent conductor  

DOEpatents

Transparent, electrically conductive and infrared-reflective films of zinc oxyfluoride are produced by chemical vapor deposition from vapor mixtures of zinc, oxygen and fluorine-containing compounds. The substitution of fluorine for some of the oxygen in zinc oxide results in dramatic increases in the electrical conductivity. For example, diethyl zinc, ethyl alcohol and hexafluoropropene vapors are reacted over a glass surface at 400.degree. C. to form a visibly transparent, electrically conductive, infrared reflective and ultraviolet absorptive film of zinc oxyfluoride. Such films are useful in liquid crystal display devices, solar cells, electrochromic absorbers and reflectors, energy-conserving heat mirrors, and antistatic coatings.

Gordon, Roy G. (Cambridge, MA)

1991-02-05

197

Flexible dye solar cells  

NASA Astrophysics Data System (ADS)

Strategies towards flexible solid state solar cells based on nanocrystalline titanium oxide and organic hole conductor were investigated. For the flexible cell geometry a metal foil was used as substrate and a semi-transparent gold layer as counter electrode which allows light transmission (back illumination). The device performance of solid state cells based on SnO2:F coated glass on the one hand and a metal foil on the other hand were characterized and compared by measuring the current voltage curves on back and front illumination.

Rossier-Iten, Nathalie; Meyer, Toby B.; Krueger, Jessica; Graetzel, Michael

2004-02-01

198

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

2006-09-01

199

Zinc retention differs between primary and transformed cells in response to zinc deprivation.  

PubMed

Previous studies in our laboratory have demonstrated that reducing the availability of zinc with the extracellular metal chelator DTPA (diethylenetriaminepentaacetate) enhances, rather than inhibits, the thyroid hormone induction of growth hormone mRNA in GH3 rat anterior pituitary tumor cells. To understand the actions of the chelator on cellular zinc status, we observed the effects of DTPA on (65)Zn uptake and retention. DTPA reduced the uptake of (65)Zn by GH3 cells from the medium, but when GH3 cells were prelabeled with (65)Zn, it resulted in greater retention of the isotope. In primary hepatocytes, DTPA both reduced the uptake of (65)Zn from the medium and increased efflux from prelabeled cells. To investigate this difference, we studied the effects of DTPA on radioactive zinc flux in the H4IIE (rat hepatoma), MCF-7 (human breast cancer) and Hs578Bst (nontransformed human mammary) cell lines and in rat primary anterior pituitary cells. DTPA reduced the uptake of (65)Zn in all cell lines examined. DTPA increased the retention of (65)Zn in prelabeled H4IIE, MCF-7 and Hs578Bst cells but reduced it in primary pituitary cells. Time course experiments showed that (65)Zn efflux is shut down rapidly by DTPA in transformed cells, whereas the chelator causes greater efflux from primary hepatocytes over the first 6 h. Experiments with (14)C-labeled DTPA confirmed that this chelator does not cross cell membranes, showing that it operates entirely within the medium. Expression of ZnT-1, the efflux transporter, was not affected by DTPA in H4IIE cells. Thus, zinc deprivation enhanced zinc retention in established cell lines but increased efflux from primary cells, perhaps reflecting differing requirements for this mineral. PMID:19269154

Dutta, Amrita; Schaller, Matthew; Franco, Aime T; Sankavaram, Kavitha; Grattan, Bruce J; Freake, Hedley C

2010-02-01

200

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.; Grätzel, Michael

2008-10-01

201

Advances in solar cell technology  

Microsoft Academic Search

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 considered with respect to the requirements of satellite solar power systems.

Geoffrey A. Landis; Sheila G. Bailey

1995-01-01

202

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

203

Compound polycrystalline solar cells  

Microsoft Academic Search

A historical perspective on the development of polycrystalline thin-film solar cells based on CdTe and CuInSe2 is presented, and recent progress of these thin-film technologies is discussed. Impressive improvements in the efficiency of laboratory scale devices has not been easy to translate to the manufacturing environment, principally due to our lack of understanding of the basic science and engineering of

Robert W. Birkmire

2001-01-01

204

Solar-cell  

SciTech Connect

A solar cell having a rear side contact and a conduction path system as front side contact. The gist of the invention is that a region of the second conductivity type is disposed on all sides of a semiconductor member of the first conductivity type, and that the rear side contact ohmically contacts the semiconductor member of the first conductivity type by penetrating the region of the second conductivity type.

Rasch, K.-D.; Flodl, H.

1985-09-24

205

Quantum Dot Solar Cells  

Microsoft Academic Search

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

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

2002-01-01

206

Deposition of transparent conducting oxides for solar cells  

SciTech Connect

Transparent conductors are needed as the front surface electrodes in all types of solar cells. The electrical and optical performance of a transparent conductor may be rated by a figure of merit defined as the ratio of the electrical conductivity to the optical absorption coefficient of the layer. Fluorine-doped zinc oxide is shown to have the highest figure of merit. ZnO:F films with a sheet resistance of 5 ohms per square can have a visible absorption of less than 3 per cent. This high performance makes zinc oxide a candidate for replacing tin oxide in thin film amorphous silicon solar cells, or for replacing part of the highly-doped silicon layer in crystalline silicon solar cells. A new, cost-effective process is described for the chemical vapor deposition of ZnO:F at atmospheric pressure. {copyright} {ital 1997 American Institute of Physics.}

Gordon, R.G. [Chemical Laboratories, Harvard University Cambridge, Massachusetts 02138 (United States)

1997-02-01

207

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

208

Decreased intracellular zinc in human tumorigenic prostate epithelial cells: a possible role in prostate cancer progression  

Microsoft Academic Search

BACKGROUND: Zinc plays important roles in maintaining normal function of the prostate and in development of prostate malignancy. It has been demonstrated that prostate malignant epithelial cells contain much less cellular zinc than the surrounding normal epithelial cells. However, the pathway(s) which leads to lower zinc accumulation in malignant prostate epithelial cells is poorly understood. In this study, the zinc

Liping Huang; Catherine P Kirschke; Yunfan Zhang

2006-01-01

209

Motexafin Gadolinium and Zinc Induce Oxidative Stress Responses and Apoptosis in B-Cell Lymphoma Lines  

Microsoft Academic Search

There is an emerging appreciation of the importance of zinc in regulating cancer cell growth and proliferation. Recently, we showed that the anticancer agent motexafin gadolinium (MGd) disrupted zinc metabolism in A549 lung cancer cells, leading, in the presence of exogenous zinc, to cell death. Here, we report the effect of MGd and exogenous zinc on intracellular levels of free

Philip S. Lecane; Mazen W. Karaman; Mint Sirisawad; Louie Naumovski; Richard A. Miller; Joseph G. Hacia; Darren Magda

2005-01-01

210

Silicon Solar Cell Turns 50  

SciTech Connect

This short brochure describes a milestone in solar (or photovoltaic, PV) research-namely, the 50th anniversary of the invention of the first viable silicon solar cell by three researchers at Bell Laboratories.

Perlin, J.

2004-08-01

211

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

212

Solar cells - A technology assessment  

Microsoft Academic Search

A qualitative assessment is made of the state-of-the-art in solar cell development and materials, together with projections of areas of future progress. The benefits and deficiencies of solar cells are surveyed, including the passive, low maintenance qualities of solar cell panels, the necessity of having a back-up system at night, and the low power conversion efficiencies available from current cells,

J. R. Bolton

1983-01-01

213

Nanostructured phosphides as photoelectrode materials for artificial photosynthesis  

NASA Astrophysics Data System (ADS)

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

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

2011-09-01

214

Phosphidation of Li4Ti5O12 nanoparticles and their electrochemical and biocompatible superiority for lithium rechargeable batteries.  

PubMed

Phosphidated-Li(4)Ti(5)O(12) shows high capacity with a significantly enhanced kinetics opening new possibilities for ultra-fast charge/discharge of lithium rechargeable batteries. The in vitro cytotoxicity test proves its fabulous cell viability, indicating that the toxicity problem of nanoparticles can be also solved by phosphidation. PMID:21952411

Jo, Mi Ru; Nam, Ki Min; Lee, Youngmin; Song, Kyeongse; Park, Joon T; Kang, Yong-Mook

2011-11-01

215

Zinc transporter ZIP8 (SLC39A8) and zinc influence IFN-? expression in activated human T cells  

PubMed Central

The zinc transporter ZIP8 is highly expressed in T cells derived from human subjects. T cell ZIP8 expression was markedly up-regulated upon in vitro activation. T cells collected from human subjects who had received oral zinc supplementation (15 mg/day) had higher expression of the activation marker IFN-? upon in vitro activation, indicating a potentiating effect of zinc on T cell activation. Similarly, in vitro zinc treatment of T cells along with activation resulted in increased IFN-? expression with a maximum effect at 3.1 ?M. Knockdown of ZIP8 in T cells by siRNA decreased ZIP8 levels in nonactivated and activated cells and concomitantly reduced secretion of IFN-? and perforin, both signatures of activation. Overexpression of ZIP8 by transient transfection caused T cells to exhibit enhanced activation. Confocal microscopy established that ZIP8 is localized to the lysosome where ZIP8 abundance is increased upon activation. Loss of lysosomal labile zinc in response to activation was measured by flow cytometry using a zinc fluorophore. Zinc between 0.8 and 3.1 ?M reduced CN phosphatase activity. CN was also inhibited by the CN inhibitor FK506 and ZIP8 overexpression. The results suggest that zinc at low concentrations, through inhibition of CN, sustains phosphorylation of the transcription factor CREB, yielding greater IFN-? expression in T cells. ZIP8, through control of zinc transport from the lysosome, may provide a secondary level of IFN-? regulation in T cells.

Aydemir, Tolunay B.; Liuzzi, Juan P.; McClellan, Steve; Cousins, Robert J.

2009-01-01

216

Epitaxial solar cells fabrication  

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

217

Gallium Phosphide and the Gallium Arsenide-Gallium Phosphide System, Data Sheets.  

National Technical Information Service (NTIS)

These data sheets present a compilation of a wide range of electrical, optical and energy values for gallium phosphide and the gallium arsenidegallium phosphide system in bulk and film form. Electrical properties include lifetime and thermoelectric effect...

M. Neuberger

1965-01-01

218

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

219

Long-term temperature effects on gaas solar cells. Final report, 1 January 1978-15 April 1979  

Microsoft Academic Search

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

J. H. Heinbockel; K. H. Hong

1979-01-01

220

Method for synthesizing indium phosphide  

NASA Astrophysics Data System (ADS)

This invention relates in general to the synthesis of highly pure, crystalline, indium phosphide (InP). In a more particular aspect, this invention concerns itself with a method for synthesizing crystalline InP under pressures of from about 5 to 30 atmospheres.

Adamski, J. A.

1984-10-01

221

Method for Synthesizing Indium Phosphide.  

National Technical Information Service (NTIS)

This invention relates in general to the synthesis of highly pure, crystalline, indium phosphide (InP). In a more particular aspect, this invention concerns itself with a method for synthesizing crystalline InP under pressures of from about 5 to 30 atmosp...

J. A. Adamski

1984-01-01

222

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

223

Quantum junction solar cells.  

PubMed

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

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

2012-09-12

224

Schottky barrier solar cell  

NASA Astrophysics Data System (ADS)

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.

1981-07-01

225

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

226

EDITORIAL: Nanostructured solar cells Nanostructured solar cells  

Microsoft Academic Search

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

Neil C. Greenham; Michael Grätzel

2008-01-01

227

Carbon Nanotube Solar Cells  

PubMed Central

We present proof-of-concept all-carbon solar cells. They are made of a photoactive side of predominantly semiconducting nanotubes for photoconversion and a counter electrode made of a natural mixture of carbon nanotubes or graphite, connected by a liquid electrolyte through a redox reaction. The cells do not require rare source materials such as In or Pt, nor high-grade semiconductor processing equipment, do not rely on dye for photoconversion and therefore do not bleach, and are easy to fabricate using a spray-paint technique. We observe that cells with a lower concentration of carbon nanotubes on the active semiconducting electrode perform better than cells with a higher concentration of nanotubes. This effect is contrary to the expectation that a larger number of nanotubes would lead to more photoconversion and therefore more power generation. We attribute this to the presence of metallic nanotubes that provide a short for photo-excited electrons, bypassing the load. We demonstrate optimization strategies that improve cell efficiency by orders of magnitude. Once it is possible to make semiconducting-only carbon nanotube films, that may provide the greatest efficiency improvement.

Klinger, Colin; Patel, Yogeshwari; Postma, Henk W. Ch.

2012-01-01

228

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.; Flügge, H.; Johannes, H.-H.; Hamwi, S.; Rabe, T.; Riedl, T.; Kowalsky, W.

2011-07-01

229

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

230

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

231

GaAs Solar Cell Radiation Handbook  

NASA Technical Reports Server (NTRS)

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

Anspaugh, B. E.

1996-01-01

232

High efficiency silicon solar cells  

Microsoft Academic Search

During carrying out a project on high efficiency crystalline silicon solar cells, different materials (CZ and FZ wafers with different resistivities) and different structures were experimented upon. For improving solar cell performance, the technology of emitter passivation, AR surface texture and coating, HCl cleaning of the quartz tube, etc., were used. The best efficiency obtained to date is 18.2%

Zhao Yuwen; Li Zhongming; Mo Chundong; Lu Kun; Li Zhiming

1994-01-01

233

Inversion layer MOS solar cells  

NASA Technical Reports Server (NTRS)

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

Ho, Fat Duen

1986-01-01

234

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

235

A solar cell characteristics plotter  

NASA Astrophysics Data System (ADS)

This paper describes a solar-cell characteristics plotter with its associated sample holder. The plotter has facilities for both manual and auto-plotting, with built-in current limit against damage of the solar cell under test. Either current or power output can be plotted as a function of terminal voltage, and there is provision for marking the maximum power point on the curve. The sample holder allows the temperature of the solar cell to be varied over a range from approximately -188 to 250 C and permits investigation of other properties of materials used in the making of the solar cell, e.g. the antireflection layer. If temperature variation is not required the holder can be water cooled to prevent overheating of the solar cell during test. The plotter can also be used for the investigation of other semiconductor devices, and is ideal for use in small research and development laboratories.

Lam, Y. W.

1981-11-01

236

Transient fluctuations of intracellular zinc ions in cell proliferation  

SciTech Connect

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

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

2009-08-15

237

New Materials for Chalcogenide Based Solar Cells  

NASA Astrophysics Data System (ADS)

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

Tosun, Banu Selin

238

High-efficiency silicon space solar cells  

Microsoft Academic Search

SHARP's activities on Si solar cells developments and features of Si solar cells for space use in comparison with GaAs solar cells are presented. Two types of high-efficiency silicon solar cells and the same kinds of high-efficiency solar cells with integrated bypass function (IBF cells) were developed and qualified for space applications. The NRS\\/LBSF cells and NRS\\/BSF cells showed an

Akio Suzuki

1998-01-01

239

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.

2013-01-01

240

Back wall solar cell  

NASA Technical Reports Server (NTRS)

A solar cell is disclosed which comprises a first semiconductor material of one conductivity type with one face having the same conductivity type but more heavily doped to form a field region arranged to receive the radiant energy to be converted to electrical energy, and a layer of a second semiconductor material, preferably highly doped, of opposite conductivity type on the first semiconductor material adjacent the first semiconductor material at an interface remote from the heavily doped field region. Instead of the opposite conductivity layer, a metallic Schottky diode layer may be used, in which case no additional back contact is needed. A contact such as a gridded contact, previous to the radiant energy may be applied to the heavily doped field region of the more heavily doped, same conductivity material for its contact.

Brandhorst, H. W., Jr. (inventor)

1978-01-01

241

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

National Technical Information Service (NTIS)

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 ...

R. G. Gordon

1995-01-01

242

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

243

Mechanically refuelable zinc/air electric vehicle cells  

SciTech Connect

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 a 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 in this report 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

244

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

245

Thin monocrystalline silicon solar cells  

Microsoft Academic Search

One of the most effective approaches for a cost reduction of crystalline silicon solar cells is the better utilization of the crystals by cutting thinner wafers. However, such thin silicon wafers must have sufficient mechanical strength to maintain a high mechanical yield in cell and module manufacturing. The electrical performance of thin cells drops strongly with decreasing cell thickness if

K. A. Muenzer; Konstantin T. Holdermann; Reinhold E. Schlosser; Steffen Sterk

1999-01-01

246

Photoelectrochemical solar cells  

SciTech Connect

The first part of the book gives a current introduction to photoelectrochemistry, discussing some of the outstanding achievements accomplished in recent years. A review of the physics of semiconductors and pn junctions includes the band model of semiconductors, the optical effects, surface states and insulators. This is followed by a chapter on techniques for the characterization of semiconductors, focussing on the characterization of the interface in photoelectrochemical cells using the dielectric properties. The second part of the book covers X-ray photoelectron spectroscopy, variability of conduction due to the extent of doping and techniques for thin film deposition. The spectral characterization of a semiconductor is also considered, using photoacoustic and photothermal spectroscopy. A review of molten salt electrolyte systems followed by the preparation of chemicals through photoelectrochemical solar cells brings the reader up to date on the latest progress in this field. The last part of the book covers the basic instrumentation required for the photoelectrochemical work and its application to band gap measurement.

Santhanam, K.S.V.; Sharon, M.

1988-01-01

247

Diffusion lengths in irradiated N/P InP-on-Si solar cells  

NASA Technical Reports Server (NTRS)

Indium phosphide (InP) solar cells are being made on silicon (Si) wafers (InP/Si) to take advantage of both the radiation-hardness properties of the InP solar cell and the light weight and low cost of Si wafers compared to InP or germanium (Ge) wafers. The InP/Si cell application is for long duration and/or high radiation orbit space missions. InP/Si cells have higher absolute efficiency after a high radiation dose than gallium arsenide (GaAs) or silicon (Si) solar cells. In this work, base electron diffusion lengths in the N/P cell are extracted from measured AM0 short-circuit photocurrent at various irradiation levels out to an equivalent 1 MeV fluence of 1017 1 MeV electrons/sq cm for a 1 sq cm 12% BOL InP/Si cell. These values are then checked for consistency by comparing measured Voc data with a theoretical Voc model that includes a dark current term that depends on the extracted diffusion lengths.

Wojtczuk, Steven; Colerico, Claudia; Summers, Geoffrey P.; Walters, Robert J.; Burke, Edward A.

1995-01-01

248

Parametric study of zinc deposition on porous carbon in a flowing electrolyte cell  

Microsoft Academic Search

X-ray radiography coupled with high resolution optical densitometry, as well as optical and scanning electron microscopy, was employed to study the effect of pivotal zinc deposition parameters on the zinc morphology within a porous C foam electrode. Deposition was carried out in zinc-bromine and zinc-zinc cells with circulating electrolyte. Results on the effects of flow rate, substrate thickness, current density,

Charles D. Iacovangelo; F. G. Will

1985-01-01

249

Prospects of cascade solar cells  

Microsoft Academic Search

The level of technological development of cascade solar cells (CSS) is assessed. CSS comprise thin layers of semiconductor materials, each absorbant in a part of the solar spectrum and transparent to the rest. Lattice-matching is required between the absorbing layers and the substrates. Progress is still necessary in this area to reduce dislocations and increase the carrier lifetime. Work is

S. M. Bedair

1984-01-01

250

Comparative in vitro toxicity of seven zinc-salts towards neuronal PC12 cells.  

PubMed

Currently much attention has been given to the neurotoxicity of zinc, yet little is known about the influence of the counterions present. Therefore, we investigated the influence of different Zn(2+)-salts (concentrations range 0.05-0.3 mM) on cell viability, ATP and glutathione concentration and caspase activation in differentiated PC12 cells as a model for neuronal cells. Generally, at concentrations of 0.05 mM most Zn(2+)-salts were not cytotoxic except for zinc-citrate. At concentrations between 0.1 and 0.3 mM Zn(2+) a significant decrease in GSH and ATP levels preceded cell death induced by all salts, except of zinc-histidinate. Zinc-citrate and zinc-sulphate turned out to be the most toxic salts particularly at low concentrations. Analyses of caspase 3/7 activity showed that dependent on the concentration and the type of the salt used cell death may show more or less signs of both, necrosis and apoptosis. Interestingly, the uptake of Zn(2+) from zinc-sulphate and zinc-citrate was significantly higher than that of other salts, implicating a correlation between uptake and toxicity. In conclusion, Zn(2+)-salts could be divided into three categories with high (zinc-citrate, zinc-sulphate), moderate (zinc-orotate, zinc-acetate, zinc-chloride(,) zinc-gluconate) and low cytotoxicity (zinc-histidinate). PMID:19306923

Pavlica, Sanja; Gaunitz, Frank; Gebhardt, Rolf

2009-06-01

251

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

252

Electrolyte Loss Tendencies of Primary Silver-Zinc Cells  

NASA Technical Reports Server (NTRS)

Since silver zinc cells are not hermetically sealed, care must be taken to prevent the loss of electrolyte which can result in shorting paths within the battery box. Prelaunch battery processing is important in being able to minimize any problems with expelled electrolyte.

Thaller, Lawrence H.; Juvinall, Gordon L.

1997-01-01

253

Solar cell with back side contacts  

DOEpatents

A III-V solar cell is described herein that includes all back side contacts. Additionally, the positive and negative electrical contacts contact compoud semiconductor layers of the solar cell other than the absorbing layer of the solar cell. That is, the positive and negative electrical contacts contact passivating layers of the solar cell.

Nielson, Gregory N; Okandan, Murat; Cruz-Campa, Jose Luis; Resnick, Paul J; Wanlass, Mark Woodbury; Clews, Peggy J

2013-12-24

254

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

255

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.

256

Lysosome-Related Organelles in Intestinal Cells Are a Zinc Storage Site in C. elegans  

PubMed Central

SUMMARY Zinc is an essential trace element involved in many biological processes and human diseases. Because zinc deficiency and excess are deleterious, animals require homeostatic mechanisms to maintain zinc levels in response to dietary fluctuations. Here we demonstrate that lysosome-related organelles in intestinal cells of C. elegans, called gut granules, function as the major site of zinc storage. Zinc storage in gut granules promotes detoxification and subsequent mobilization, linking cellular and organismal zinc metabolism. The cation diffusion facilitator protein CDF-2 plays a critical role in this process by transporting zinc into gut granules. In response to high dietary zinc, gut granules displayed structural changes characterized by a bilobed morphology with asymmetric distributions of zinc and molecular markers. We defined a genetic pathway that mediates the formation of bilobed morphology. These findings elucidate mechanisms of zinc storage, detoxification and mobilization in C. elegans and may be relevant to other animals.

Roh, Hyun Cheol; Collier, Sara; Guthrie, James; Robertson, J. David; Kornfeld, Kerry

2014-01-01

257

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

258

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

259

Radiation effects in solar cells  

NASA Astrophysics Data System (ADS)

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

Imaizumi, Mitsuru; Ohshima, Takeshi

2013-05-01

260

Antireflective coating fabricated by chemical deposition of ZnO for spherical Si solar cells  

Microsoft Academic Search

ZnO thin films as an antireflective (AR) coating have been successfully fabricated on spherical Si solar cells by chemical deposition, which enables uniform film formation. ZnO films were prepared chemically by immersing the cell in an aqueous solution of zinc nitrate and dimethylamineborane maintained at 80°C. The current–voltage measurements of the solar cells confirmed the increase in short circuit current

Takashi Minemoto; Takahiro Mizuta; Hideyuki Takakura; Yoshihiro Hamakawa

2007-01-01

261

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

262

Improved silver/zinc secondary cells for underwater applications  

NASA Astrophysics Data System (ADS)

Performance improvements in silver/zinc technology have been achieved with new developments in additives and separator coatings. These improvements, aimed at increasing the cycle life and energy density of silver/zinc cells, were realized through advances in the stateof the-art of the zinc electrode and of the separators, which are the major limitations to this electrochemical couple. To achieve these objectives, two basic approaches were employed: (i) the introduction of a new class of materials known as electro permeable membranes (EPM); (ii) the use of bismuth oxide (Bi 2O 3) as an additive to the negative electrode. The EPMs are applied to the separator to provide a barrier to silver penetration without impairing performance. This allows the use of very thin separators and/or a reduction in the number of layers required. This provides an increase in the available volume for active materials with a consequent improvement in volumetric energy density. The effect of the additives to the negative electrode is to inhibit shape change and increase the conductivity of the zinc. The general approach utilized in this program was to incorporate the performance enhancing improvements into a baseline cell design. The baseline has been configured to fit two underwater vehicles currently in use by the US Navy. The development approaches and specific cell configurations are presented along with current performance data. An analysis and critique of the data coupled with conclusions and recommendations for future development activities are also presented.

Skelton, James; Serenyi, Roberto

263

Zinc protects against oxidative damage in cultured human retinal pigment epithelial cells  

Microsoft Academic Search

This study was undertaken to determine whether bioavailable zinc can influence the effects of oxidative stress on cultured human retinal pigment epithelial (RPE) cells. RPE cells were maintained for 7 d in culture medium containing 14 ?M total zinc, or in medium containing 0.55 ?M total zinc. After 1 week, MTT assays were performed to determine the relative cytotoxicity of

David J Tate; Michael V Miceli; David A Newsome

1999-01-01

264

Performance of porous plastic separators in zinc/bromine cells  

NASA Astrophysics Data System (ADS)

Bromine transport through various acetone-extracted microporous plastic materials is studied with attention given to their use as separators in zinc/bromine cells. Given the porosity and tortuosity of the materials, the samples that were acetone-extracted and then either air-dried or hot-water-quenched showed equivalent thicknesses were far less than would be expected. The measured faradaic efficiencies of cells are in good agreement with those calculated from the bromine transport properties of the chosen separators.

Cathro, K. J.; Constable, D. C.; Hoobin, P. M.

1988-01-01

265

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

266

Transparent conductive oxides for thin-film silicon solar cells  

NASA Astrophysics Data System (ADS)

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

Löffler, J.

2005-04-01

267

Zinc electrowinning analysis in a modified Hull cell  

NASA Astrophysics Data System (ADS)

The Hull cell is an analytical cell designed with trapezoidal geometry to incorporate a range of current densities into a single experiment. It was conceived to examine electroplating processes rather than mass production processes. A modified analytical cell was designed, developed and applied to the diagnosis of zinc electrowinning. Emphasis was placed on obtaining the quantitative variation of current efficiency with current density and the associated microscopic variation in deposit morphology. Current density distributions came by placing an insulating baffle in between parallel electrodes. The baffle position and length were easily adjusted, allowing the generation of 12 different distributions for a single applied potential. Ten electrically isolated 1 cm2 segments comprised the cathode. Measurement of the potential drop across I ohm resistors in each of the ten isolated parallel branches permitted direct quantitative determination of current densities. The small segments permitted simple SEM and X-ray analysis of deposits. The cell was designed to allow the continual cycling of electrolyte. In conjunction with experimental analysis, a technique for the determination of current efficiency was tested and developed. The technique involved the comparison of charge passed for the electrodeposition and subsequent electrodissolution of a given mass of zinc and removed the necessity to determine the mass directly. In no prior studies on zinc electrowinning had current efficiencies been determined this way. The cell and technique were developed and verified by the correct diagnosis of industrial zinc electrowinning. Successful determination of the effects of key variables including temperature, acid to zinc ratio and impurity effects on current efficiency and deposit morphology was demonstrated. In parallel with experimental work, cell electrochemistry was modeled. Primary and secondary input parameters were those pertinent to zinc electrowinning. The resultant simulation served as a design aid to investigate the effect of implementing changes in key process variables and cell geometry. Custom software using pattern recognition and numerical integration to determine current densities and efficiencies directly from logged data was designed, written and interfaced with data acquisition software. The resulting experimental system serves as an unprecedented bench top scale, analytical tool tailored specifically for the electrowinning industry.

McColm, Thomas Dean

268

Space solar cells—tradeoff analysis  

Microsoft Academic Search

This paper summarizes the study that had the objective to tradeoff space solar cells and solar array designs to determine the best choice of solar cell and array technology that would be more beneficial in terms of mass, area and cost for different types of space missions. Space solar cells, which are commercially now available in the market and to

M. Raja Reddy

2003-01-01

269

Point contact silicon solar cells  

NASA Technical Reports Server (NTRS)

A new type of silicon solar cell has been developed. It is called the point-contact cell because the metal semiconductor contacts are restricted to an array of small points on the back of the cell. The point contact cell has recently demonstrated 22 percent conversion efficiency at one sun and 27.5 percent at 100 suns under an AM1.5 spectrum.

Swanson, Richard M.

1987-01-01

270

Sprayed cadmium sulphide solar cells  

NASA Astrophysics Data System (ADS)

A spray process for the production of thin-film (5 microns) Cd/Cu(x)S solar cells is discussed and typical results are presented for the resulting cells. Plans for long-term very-large-scale production of cadmium sulfide cells are examined together with projected cost data and basic design criteria. A schematic representation of the cell, spray process, and an I/V curve are given.

Roderick, G. A.

271

Lithium counterdoped silicon solar cell  

NASA Technical Reports Server (NTRS)

The resistance to radiation damage of an n(+)p boron doped silicon solar cell is improved by lithium counterdoping. Even though lithium is an n-dopant in silicon, the lithium is introduced in small enough quantities so that the cell base remains p-type. The lithium is introduced into the solar cell wafer by implantation of lithium ions whose energy is about 50 keV. After this lithium implantation, the wafer is annealed in a nitrogen atmosphere at 375 C for two hours.

Weinberg, I. (inventor); Brandhorst, H. W., Jr. (inventor)

1986-01-01

272

Low Cost Solar Cell Arrays.  

National Technical Information Service (NTIS)

Limitations in both space and terrestial markets for solar cells are described. Based on knowledge of the state-of-the-art, six cell options are discussed; as a result of this discussion, the three most promising options (involving high, medium and low ef...

P. A. Iles H. Mclennan

1975-01-01

273

A proteomic view of the response of Paracoccidioides yeast cells to zinc deprivation.  

PubMed

Zinc plays a critical role in a diverse array of biochemical processes. However, an excess of zinc is deleterious to cells; therefore, cells require finely tuned homeostatic mechanisms to balance the uptake and the storage of zinc. There is also increasing evidence supporting the importance of zinc during infection. To understand better how Paracoccidioides adapts to zinc deprivation, we compared the two-dimensional (2D) gel protein profile of yeast cells during zinc starvation to yeast cells grown in a zinc rich condition. Protein spots were selected for comparative analysis based on the protein staining intensity, as determined by image analysis. In response to zinc deprivation, a total of 423 out of 845 protein spots showed a significant change in abundance. Quantitative RT-qPCR analysis of RNA from Paracoccidioides grown under zinc restricted conditions validated the correlation between the differentially regulated proteins and transcripts. According to the proteomic data, zinc deficiency may be a stressor to Paracoccidioides, as suggested by the upregulation of a number of proteins related to stress response, cell rescue, and virulence. Other process induced by zinc deprivation included gluconeogenesis. Conversely, the methylcitrate cycle was downregulated. Overall, the results indicate a remodelling of the Paracoccidioides response to the probable oxidative stress induced during zinc deprivation. PMID:23809650

Parente, Ana Flávia Alves; de Rezende, Tereza Cristina Vieira; de Castro, Kelly Pacheco; Bailão, Alexandre Melo; Parente, Juliana Alves; Borges, Clayton Luiz; Silva, Luciano Paulino; Soares, Célia Maria de Almeida

2013-06-01

274

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

275

Fabrication of 7.2% efficient CZTSSe solar cells using CZTS nanocrystals.  

PubMed

Earth abundant copper-zinc-tin-chalcogenide (CZTSSe) is an important class of material for the development of low cost and sustainable thin film solar cells. The fabrication of CZTSSe solar cells by selenization of CZTS nanocrystals is presented. By tuning the composition of the CZTS nanocrystals and developing a robust film coating method, a total area efficiency as high as 7.2% under AM 1.5 illumination and light soaking has been achieved. PMID:21090644

Guo, Qijie; Ford, Grayson M; Yang, Wei-Chang; Walker, Bryce C; Stach, Eric A; Hillhouse, Hugh W; Agrawal, Rakesh

2010-12-15

276

Texture Etched ZnO:Al for Silicon Thin Film Solar Cells  

Microsoft Academic Search

This chapter provides an overview of the physical principles and the application of zinc oxide in thin film silicon solar\\u000a cells. Focus will be on the method of magnetron sputtering followed by a wet-chemical etching step to achieve the required\\u000a surface roughness of the films. We will start with some basics of thin film silicon solar cell design and operation,

J. Hüpkes; J. Müller; B. Rech

277

Printing efficient solar cells  

Microsoft Academic Search

As worldwide demand for fossil fuels depletes reserves, scien- tists are increasingly focused on generating alternative energy— especially if it can be produced cleanly and inexpensively. Hy- droelectric, solar, wind, nuclear, and biomass technologies are replacing coal, oil, and natural gas. Many of these new tech- nologies have similar costs. Yet the availability of materials or existing infrastructure can affect

Ritesh Tipnis; Darin Laird

2008-01-01

278

Silicon concentrator solar cell research  

SciTech Connect

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

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

1993-06-01

279

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

280

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.

Blewett, Heather J.; Taylor, Carla G.

2012-01-01

281

Effect of folate supplementation on zinc status in patients with sickle cell disease  

Microsoft Academic Search

Folate supplementation as in other chronic haemolytic anaemias is recommended rou- tinely for patients with sickle cell disease (SCD). However, folate intake has been suggested to have adverse effects on zinc status especially in zinc-deficient subjects. In this study we examined zinc status in patients with SCD on folate supplementation. Twenty patients with SCD and 10 healthy controls received folate

Filiz Kaynak; Emel Gurkan; Meral Urunsak; Fikri Baslamisli; Rikkat Kocak

282

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

283

High-efficiency silicon solar cell research  

NASA Technical Reports Server (NTRS)

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

Daud, T.

1984-01-01

284

Phthalocyanine based Schottky solar cells  

NASA Astrophysics Data System (ADS)

Phthalocyanine (Pc) materials are commonly used in organic solar cells. Four different phthalocyanines, nickel phthalocyanine (NiPc), copper phthalocyanine (CuPc), iron phthalocyanine (FePc), and cobalt phthalocyanine (CoPc) have been investigated for organic solar cell applications. The devices consisted of indium tin oxide (ITO) coated lass substrate, Pc layer, and aluminum (al) electrode. It has been found that ITO/CuPc/Al Schottky cell exhibits the best performance. To investigate the influence of the active layer thickness on the cell performance, cells with several different thicknesses were fabricated and optimal value was found. Schottky cell exhibits optimal performance with one ohmic and one barrier contact. However, it is suspected that ITO/CuPc contact is not ohmic. Therefore, we have investigated various ITO surface treatments for improving the performance of CuPc based Schottky solar cell. We have found that cell on ITO treated with HCl and UV-ozone exhibits the best performance. AM1 power conversion efficiency can be improved by 30% compared to cell made with untreated ITO substrate. To improve power conversion efficiency, double or multiplayer structure are required, and it is expected that suitable ITO treatments for those devices will further improve their performance by improving the contact between ITO and phthalocyanine layer.

Kwong, Chung Yin; Djurisic, Aleksandra B.; Lam, Lillian S. M.; Chan, Wai Kin

2003-02-01

285

On the suppression of self discharge of the zinc electrodes of zinc-air cells and other related battery systems  

NASA Astrophysics Data System (ADS)

A simple procedure is developed to determine the mercury content, without resorting to any analytical procedures, in the chemically amalgamated zinc electrode of zinc-air cells and other related battery systems. A small percentage of mercury is employed in these electrodes in order to increase the hydrogen overvoltage, minimize the self-discharge, and provide an equipotential surface ensuring uniform corrosion. A simple alloying method is developed as an alternative to the method of Bernard (1970). The ampere hour outputs of several experimental 1.4 V, 50 A h zinc-air alkaline cells are presented in order to show that this alloying procedure is more effective than the chemical method, especially when the amalgamated zinc is stored prior to use.

Chakkaravarthy, C.; Udupa, H. V. K.

1983-07-01

286

Spectral coupling of fluorescent solar concentrators to plasmonic solar cells  

NASA Astrophysics Data System (ADS)

Coupling luminescent solar concentrators (LSC) with plasmonic solar cells is a potential method to increase conversion efficiency while reducing cost associated with large-area photovoltaic and solar-tracking systems. Specifically, the emission spectrum of the fluorescent dye in the LSC can be matched to the absorption spectrum in the photovoltaic cell which can be tuned by surface plasmon resonance. Here we investigate this concept employing organic solar cells with plasmonic silver nanoparticles and polymethylmethacrylate-based solar concentrators with Lumogen Red dye. The absorption enhancement is predicted by Mie theory, taking size effect on dielectric properties into consideration. A factor of two increase of conversion efficiency is obtained when the absorption peak in the solar cell is tuned to match the emission peak of Lumogen Red dye. A similar approach could be employed to enhance the efficiency of other LSC-photovoltaic systems including those based on silicon solar cells with different surface plasmonic nanostructures.

Wang, Shu-Yi; Borca-Tasciuc, Diana-Andra; Kaminski, Deborah A.

2011-04-01

287

Large area thin film cadmium telluride heterojunction solar cells  

SciTech Connect

Cadmium telluride films have been deposited by the direct combination of the elements on the surface of heated substrates in hydrogen. The resistivity of p-type films was controlled by using a cadmium-deficient reaction mixture, and adding a dopant to a nearly stoichiometric reaction mixture. Heterojunction solar cells were prepared from p-type cadmium telluride films by using cadmium oxide, cadmium sulfide, tin-doped indium oxide, and zinc oxide, deposited by ionbeam sputtering, spray pyrolysis, or vacuum evaporation, as the window material. Thus far, n-ITO/p-CdTe solar cells have the highest AM1 efficiency, 8.1% for cells of 1 cm/sup 2/ area. All heterojunction cells exhibit some degradation under continuous illumination, which may be minimized by passivation.

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

1984-05-01

288

Solar cell circuit and method for manufacturing solar cells  

NASA Technical Reports Server (NTRS)

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

Mardesich, Nick (Inventor)

2010-01-01

289

Investigation of low-zinc-solubility electrodes and electrolytes in zinc/silver oxide cells  

NASA Astrophysics Data System (ADS)

The cycle-life performance of the Zn/AgO cell is limited by high rates of Zn active material redistribution (shape change) and Zn dendrite growth. Reduced-zinc-solubility electrolytes, prepared by adding F -, CO 32-, BO 33- and PO 43- salts to aqueous KOH solutions, were used in 5 A h Zn/AgO cells to determine their effect on cell lifetimes. Ca(OH) 2 additions to the Zn electrode were also evaluated in cells of the same capacity and mass as the calcium-free cells. It was found that all of the anion additives to KOH electrolytes resulted in lower cell capacities and shorter lifetimes, which could be attributed the formation of soluble Ag-containing salts and subsequent degradation of the Ag electrode performance. The calcium-containing Zn electrode was found to significantly improve the performance of the Zn/AgO cell by promoting higher capacities, especially over the initial 20 cycles. The higher capacities could be attributed to the formation of a calcium zincate complex, crystals of which were found in the cycled Zn electrodes.

Chen, Jenn-Shing; McLarnon, Frank R.; Cairns, Elton J.

290

Engineered zinc finger proteins for controlling stem cell fate.  

PubMed

Stem cells are functionally defined as progenitor cells that can self-renew and differentiate. Critical transitions in these cells are controlled via signaling pathways and subsequent transcriptional regulation. Technologies capable of modulating the levels of gene expression, especially those of transcription factors, represent powerful tools for research and could potentially be used in therapeutic applications. In this study, we evaluated the ability of synthetic zinc finger protein transcription factors (ZFP-TFs) to cause the differentiation of embryonic stem (ES) cells. We constructed ZFP-TFs that target the mouse Oct-4 gene (which is a major regulator of ES cell pluripotency and self-renewal). These designed transcription factors were able to regulate the transcription of Oct-4, affecting the expression of downstream genes and thus regulating ES cell differentiation. PMID:14595122

Bartsevich, Victor V; Miller, Jeffrey C; Case, Casey C; Pabo, Carl O

2003-01-01

291

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

292

Silicon Formation for Solar Cells  

NASA Technical Reports Server (NTRS)

Highly pure silicon obtained for solar cells by proposed technique that sprays liquid-sodium droplets into SiF4 gas. Resulting freely flowing powder of silicon and sodium fluoride will not adhere to reactor walls and easily transferred to melt separator to recover silicon.

Sancier, K.

1985-01-01

293

Method of fabricating solar cells  

Microsoft Academic Search

This patent describes a method of fabricating a solar cell. It comprises providing a substrate in the form of a silicon ribbon having front and back surfaces and a polygonal edge configuration formed by a series of side edge surfaces; using a source of phosphorus to form a PN junction in the substrate so that the junction extends adjacent to

R. H. Micheels; P. Valdivia; J. I. Hanoka

1992-01-01

294

Dye-sensitized solar cells  

Microsoft Academic Search

The dye-sensitized solar cells (DSC) provides a technically and economically credible alternative concept to present day p–n junction photovoltaic devices. In contrast to the conventional systems where the semiconductor assume both the task of light absorption and charge carrier transport the two functions are separated here. Light is absorbed by a sensitizer, which is anchored to the surface of a

Michael Grätzel

2003-01-01

295

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

296

Solar cells: past, present, future  

Microsoft Academic Search

This paper gives an up to date perspective of PV technology and materials. The most important material has been and still is silicon. It dominates the present world market, particularly in its crystalline form but amorphous silicon is also of importance. Crystalline silicon solar cells are still heavily dependent on the materials base of the semiconductor industry. This material still

Adolf Goetzberger; Joachim Luther; Gerhard Willeke

2002-01-01

297

Zinc pretreatment prevents hepatic stellate cells from cadmium-produced oxidative damage  

Microsoft Academic Search

Pretreatment with zinc produces tolerance to several cadmium toxic effects. This study was performed to further elucidate\\u000a the mechanism of zinc-induced tolerance to cadmium cytotoxicity in a rat hepatic stellate cell line (CFSC-2G). Twenty four\\u000a hours after seeding, cells were treated with 60 ?mol\\/L ZnCl2 for 24 h. Following zinc pretreatment, cells were exposed to 3 ?mol\\/L and 5 ?mol\\/L

V. Souza; M. del C. Escobar; L. Bucio; E. Hernfindez; M. C. Gutiérrez-Ruiz

2004-01-01

298

Development of long-lived high-performance zinc-calcium\\/nickel oxide cells  

Microsoft Academic Search

The addition of Ca(OH)2 to the zinc electrode of Zn\\/KOH\\/NiOOH cells was investigated in order to determine its effect on the rate of zinc active material redistribution (shape change) and cell cycle-life performance. Cells of equal mass and capacity, and therefore the same specific energy, containing 0, 10, 25, and 40 mol% Ca(OH)2 in their zinc electrodes were constructed and

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

1992-01-01

299

New methods for solar cells measurement by LED solar simulator  

Microsoft Academic Search

A solar simulator for solar cells is an important tool to measure their performance. At present, xenon and halogen lamp is used at most laboratories. It is considerably accurate, but the facility is so large and so expensive. Therefore, a solar simulator using LED (light-emitting diode) lamps is proposed, that is low-cost and portable, and was invented to its capability.

S. Kohraku; K. Kurokawa

2003-01-01

300

Solar cell crack inspection by image processing  

Microsoft Academic Search

Spacecraft operate in a hostile environment, far from the Earth, so it is necessary for solar cells with anti-radiation properties to have a bonding process carried out on them. After bonding, an essential process for the solar cell assembly is to inspect for cracks on the edges or inside the solar cell. To avoid utilizing unqualified products and to improve

Fu Zhuang; Zhao Yanzheng; Liu Yang; Cao Qixin; Chen Mingbo; Zhang Jun; Jay Lee

2004-01-01

301

Performance limitations of silicon solar cells  

Microsoft Academic Search

This paper discusses the performance limitations of silicon solar cells which have been identified and investigated using a detailed numerical analysis of solar cell operation. Efficiency limitations are discussed as related to doping densities, minority carrier lifetimes, widths of solar cell regions, surface recombination, antireflecting layers, and ohmic contact stripes. Areas in which improvements can be expected in performance are

JOHN R. HAUSER; PETER M. DUNBAR

1977-01-01

302

Method of fabricating solar cell modules  

Microsoft Academic Search

The solar cell module of this invention is fabricated by placing an array of solar cells in a suitable mold having a bottom surface, an entry port and an exit port. A light transparent superstrate effectively serves as the top for the mold and is placed over the array of solar cells in the mold. The superstrate is spaced from

W. B. Andrulitis; W. T. Kurth; S. G. Miles

1980-01-01

303

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

NASA Astrophysics Data System (ADS)

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

Vijayakumar, Vishnuvardhanan

304

Zinc at cytotoxic concentrations affects posttranscriptional events of gene expression in cancer cells.  

PubMed

Zinc at cytotoxic concentrations has been shown to regulate gene transcription in cancer cells, though zinc's involvement in posttranscriptional regulation is less characterized. In this study, we investigated the involvement of cytotoxic zinc in the posttranscriptional steps of gene expression. Clioquinol, a well-established zinc ionophore, was used to raise intracellular zinc to reported cytotoxic levels. The MCF-7 human cancer cell line was applied as a cell model system. Several parameters were used as indictors of posttranscriptional regulation, including p-body formation, microRNA profiling, expression level of proteins known to regulate mRNA degradation, microRNA processing, and protein translation. p-body formation was observed in MCF-7 cells using several molecules known as p-body components. Clioquinol plus zinc enhanced p-body assembly in MCF-7 cells. This enhancement was zinc-specific and could be blocked by a high affinity zinc chelator. The enhancement does not seem to be due to a stress response, as paclitaxel, a commonly used chemotherapeutic, did not cause enhanced p-body formation at a highly cytotoxic concentration. microRNA profiling indicated that clioquinol plus zinc globally down-regulates microRNA expression in this model system, which is associated with the reduced expression of Dicer, an enzyme key to microRNA maturation, and Ago2, a protein essential for microRNA stability. This study demonstrates that ionophoric zinc can induce cytotoxicity in cancer cells by globally regulating posttranscriptional events. PMID:22415087

Zheng, Jie; Zhang, Xiao-Xi; Yu, Haijun; Taggart, Jori E; Ding, Wei-Qun

2012-01-01

305

New trends for solar cell development and recent progress of dye sensitized solar cells  

Microsoft Academic Search

This article reviews the new concepts and new trends of solar cell development. To increase the photoelectric conversion efficiency,\\u000a reduce the cost, and for application in a much broader field, thin film solar cell, flexible solar cell, and tandem solar\\u000a cell have become important subjects to be studied. As the representative of the solar cells of the third generation, the

Hong Lin; Wen-li Wang; Yi-zhu Liu; Xin Li; Jian-bao Li

2009-01-01

306

Zinc at Sub-Cytotoxic Concentrations Induces Heme Oxygenase-1 Expression in Human Cancer Cells  

PubMed Central

Background/Aims This study investigated the effects of zinc on heme oxygenase-1 (HO-1) expression in human cancer cells. Methods/Results Zinc at sub-cytotoxic concentrations (50–100 µM) induces HO-1 expression in the MDA-MB-231 (human breast cancer) and A2780 (human ovarian cancer) cell lines in a concentration- and time-dependent manner. The induction of HO-1 by zinc was detected after 4–6 hours of treatment, reached maximal level at 8 hours, and declined thereafter. Using a human HO-1 gene promoter reporter construct, we identified two antioxidant response elements (AREs) that mediated the zinc-induced increase in HO-1 gene transcription, indicating that the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling pathway is involved in this event. This assumption was supported by the observations that knockdown of Nrf2 expression compromised the zinc-induced increase in HO-1 gene transcription, and that zinc increased Nrf2 protein expression and the Nrf2 binding to the AREs. Additionally, we found that the zinc-induced HO-1 gene transcription can be enhanced by clioquinol, a zinc ionophore, and reversed by pretreatment with TPEN, a known zinc chelator, indicating that an increase in intracellular zinc levels is responsible for this induction. Conclusion These findings demonstrate that zinc at sub-cytotoxic concentrations induces HO-1 expression in human cancer cells. The biological significance of this induction merits further investigation.

Xue, Jing; Wang, Shuai; Wu, Jinchang; Hannafon, Bethany N.; Ding, Wei-Qun

2013-01-01

307

Heat-Sterilized Silver Oxide-Zinc Cells Cycle Life Studies.  

National Technical Information Service (NTIS)

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 th...

J. T. Arms

1973-01-01

308

Reregistration Eligibility Decision (RED): AL and MG Phosphide. (Includes RED Facts: Aluminum and Magnesium Phosphide Fact Sheet).  

National Technical Information Service (NTIS)

This document presents the Agency's decision regarding the reregistration eligibility of the registered uses of aluminum and magnesium phosphide. Section I is the introduction. Section II describes aluminum and magnesium phosphide, their uses, data requir...

1998-01-01

309

GaAs Solar Cell Radiation Handbook  

NASA Technical Reports Server (NTRS)

The handbook discusses the history of GaAs solar cell development, presents equations useful for working with GaAs solar cells, describes commonly used instrumentation techniques for assessing radiation effects in solar cells and fundamental processes occurring in solar cells exposed to ionizing radiation, and explains why radiation decreases the electrical performance of solar cells. Three basic elements required to perform solar array degradation calculations: degradation data for GaAs solar cells after irradiation with 1 MeV electrons at normal incidence; relative damage coefficients for omnidirectional electron and proton exposure; and the definition of the space radiation environment for the orbit of interest, are developed and used to perform a solar array degradation calculation.

Anspaugh, B. E.

1996-01-01

310

Towards stable silicon nanoarray hybrid solar cells.  

PubMed

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

311

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

312

Development of Single Cell Protectors for Sealed Silver-Zinc Cells, Phase 1.  

National Technical Information Service (NTIS)

A single cell protector (SCP) assembly capable of protecting a single silver-zinc (Ag Zn) battery cell was designed, fabricated, and tested. The SCP provides cell-level protection against overcharge and overdischarge by a bypass circuit. The bypass circui...

B. Murray, J. W. Lear, M. S. Imamura, R. L. Donovan

1976-01-01

313

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

314

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

315

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

316

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

317

Zyxin: zinc fingers at sites of cell adhesion.  

PubMed

Zyxin is a low abundance phosphoprotein that is localized at sites of cell-substratum adhesion in fibroblasts. Zyxin displays the architectural features of an intracellular signal transducer. The protein exhibits an extensive proline-rich domain, a nuclear export signal and three copies of the LIM motif, a double zinc-finger domain found in many proteins that play central roles in regulation of cell differentiation. Zyxin interacts with alpha-actinin, members of the cysteine-rich protein (CRP) family, proteins that display Src homology 3 (SH3) domains and Ena/VASP family members. Zyxin and its partners have been implicated in the spatial control of actin filament assembly as well as in pathways important for cell differentiation. Based on its repertoire of binding partners and its behavior, zyxin may serve as a scaffold for the assembly of multimeric protein machines that function in the nucleus and at sites of cell adhesion. PMID:9394617

Beckerle, M C

1997-11-01

318

Degradation mechanism of ZnO-based dye-sensitized solar cells  

Microsoft Academic Search

Zinc oxide (ZnO)-based dye-sensitized solar cell was fabricated and tested under constant solar simulator illumination until the photocurrent decreased. Electrolyte and dye were studied by Fourier transform infrared and UV–vis absorption spectroscopy. Scanning electron microscopy, photoluminescence and X-ray photoelectron spectroscopy were used to study the degradation of ZnO. Secondary Ion Mass spectroscopy was used to analyze the structural change of

Lin Ke; Surani Bin Dolmanan; Lu Shen; Pramoda Kumari Pallathadk; Zheng Zhang; Doreen Mei Ying Lai; Hong Liu

2010-01-01

319

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

320

A global view of the selectivity of zinc deprivation and excess on genes expressed in human THP-1 mononuclear cells  

PubMed Central

Among the micronutrients required by humans, zinc has particularly divergent modes of action. cDNA microarray and quantitative PCR technologies were used to investigate the zinc responsiveness of known genes that influence zinc homeostasis and to identify, through global screening, genes that may relate to phenotypic outcomes of altered dietary zinc intake. Human monocytic/macrophage THP-1 cells were either acutely zinc depleted, using a cell-permeable zinc-specific chelator, or were supplemented with zinc to alter intracellular zinc concentrations. Initially, genes associated with zinc homeostasis were evaluated by quantitative PCR to establish ranges for fold changes in transcript abundance that might be expected with global screening. Zinc transporter-1 and zinc transporter-7 expression increased when cellular zinc increased, whereas Zip-2 expression, the most zinc-responsive gene examined, was markedly increased by zinc depletion. Microarrays composed of ?22,000 elements were used to identify those genes responsive to either zinc depletion, zinc supplementation, or both conditions. Hierarchal clustering and ANOVA revealed that ?5% or 1,045 genes were zinc responsive. Further sorting based on this pattern of the zinc responsiveness of these genes into seven groups revealed that 104 genes were linearly zinc responsive in a positive mode (i.e., increased expression as cellular zinc increases) and 86 genes that were linearly zinc responsive in a negative mode (i.e., decreased expression as cellular zinc increases). Expression of some genes was responsive to only zinc depletion or supplementation. Categorization by function revealed numerous genes needed for host defense were among those identified as zinc responsive, including cytokine receptors and genes associated with amplification of the Th1 immune response.

Cousins, Robert J.; Blanchard, Raymond K.; Popp, Michael P.; Liu, Li; Cao, Jay; Moore, J. Bernadette; Green, Calvert L.

2003-01-01

321

Solar cells: Folding photons  

NASA Astrophysics Data System (ADS)

Scientists have shown that wrinkles and folds can be used to maximize the absorption of low-energy photons by efficiently redirecting them into a thin absorbing film. This inexpensive technique for structuring photonic substrates could be used to increase the efficiency of many organic photovoltaic cells.

Gregg, Brian A.; van de Lagemaat, Jao

2012-05-01

322

Relationship between Painful Crisis and Serum Zinc Level in Children with Sickle Cell Anaemia  

PubMed Central

Sickle cell anaemia (SCA) is associated with zinc deficiency; zinc supplementation may ameliorate some of its clinical manifestations including the relief of painful crisis. Subjects and Methods. Serum zinc levels were determined in 71 children with SCA and painful crisis and in equal numbers in steady state. Seventy-one children with AA genotype acted as controls. Qualitative assessment of zinc content of 24-hour dietary recall and the last meal consumed before blood was drawn was taken. Serum zinc was determined using atomic absorption spectrophotometer. Haemoglobin concentration and packed cell volume (PCV) were determined using standard methods. Results. The mean serum zinc concentration in the study was less than international reference range. The controls had significantly higher serum zinc concentrations than the SCA group (42.7 ± 13.6 versus 32.3 ± 14.0??g/dL, P < .000); this difference was due to the significantly lower values of serum zinc in SCA with painful crisis compared with the remaining two groups F = 30.9, P<.000. There was a positive correlation between serum zinc and haemoglobin concentration only in the control group (r = 0.4; P = .001). Conclusion. The serum zinc levels in this study were low. Painful crisis in SCA may exert greater demand for zinc utilization in children with SCA thereby resulting in lower serum levels.

Temiye, Edamisan Olusoji; Duke, Edem Samuel; Owolabi, Mbang Adeyemi; Renner, James Kweku

2011-01-01

323

Role of cellular zinc in programmed cell death: temporal relationship between zinc depletion, activation of caspases, and cleavage of Sp family transcription factors.  

PubMed

Zinc is a potent inhibitor of apoptosis, whereas zinc depletion induces apoptosis in many cell lines. To investigate the mechanisms of zinc depletion-induced apoptosis, HeLa cells were treated with the membrane permeable metal ion chelator, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN). TPEN decreased the intracellular level of zinc and induced apoptosis with a characteristic cellular pattern, i.e. cell shrinkage and formation of apoptotic bodies, with DNA fragmentation and formation of a typical DNA ladder pattern. Following TPEN treatment, caspases-3, -8, and -9 were activated and caspase target proteins, poly(ADP-ribose) polymerase, and Sp transcription factors were cleaved. These effects were inhibited by adding zinc to the medium. To assess the role of zinc in the activation of the caspase cascade, we compared zinc inhibition during tumor necrosis factor alpha/cycloheximide- and etoposide-induced apoptosis with that induced by TPEN. Zinc addition partially inhibited caspase-3 activation, but not caspase-8 and -9 cleavage in HeLa cells treated with tumor necrosis factor alpha or etoposide. These results suggest that caspase-3 is rapidly and directly activated by zinc chelation, without a requirement for an upstream event. Caspase-3 activation is therefore the main event leading to apoptosis after intracellular zinc chelation. Finally, we conclude that cellular zinc inhibits apoptosis by maintaining caspase-3 inactive. PMID:11377396

Chimienti, F; Seve, M; Richard, S; Mathieu, J; Favier, A

2001-07-01

324

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).

Schleith, Susan; Hall, Penny

2007-01-01

325

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

326

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

327

Solar Cells for Lunar Application  

NASA Technical Reports Server (NTRS)

In this work a preliminary study of the vacuum evaporation of silicon extracted from the lunar regolith has been undertaken. An electron gun vacuum evaporation system has been adapted for this purpose. Following the calibration of the system using ultra high purity silicon deposited on Al coated glass substrates, thin films of lunar Si were evaporated on a variety of crystalline substrates as well as on glass and lightweight 1 mil (25 microns) Al foil. Extremely smooth and featureless films with essentially semiconducting properties were obtained. Optical absorption analysis sets the bandgap (about 1.1 eV) and the refractive index (n=3.5) of the deposited thin films close to that of crystalline silicon. Secondary ion mass spectroscopy and energy dispersive spectroscopy analysis indicated that these films are essentially comparable to high purity silicon and that the evaporation process resulted in a substantial reduction of impurity levels. All layers exhibited a p-type conductivity suggesting the presence of a p-type dopant in the fabricated layers. While the purity of the 'lunar waste material' is below that of the 'microelectronic-grade silicon', the vacuum evaporated material properties seems to be adequate for the fabrication of average performance Si-based devices such as thin film solar cells. Taking into account solar cell thickness requirements (greater than 10 microns) and the small quantities of lunar material available for this study, solar cell fabrication was not possible. However, the high quality of the optical and electronic properties of evaporated thin films was found to be similar to those obtained using ultra-high purity silicon suggest that thin film solar cell production on the lunar surface with in situ resource utilization may be a viable approach for electric power generation on the moon.

Freundlich, Alex; Ignatiev, Alex

1997-01-01

328

High Temperature Solar Cell Development  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

329

MIS and SIS solar cells  

Microsoft Academic Search

This review paper shows that MIS (metal-insulator-semiconductor) and SIS (semiconductor-insulator-semiconductor) solar cells are basically one and the same type of device, even though they are usually regarded as being separate and are reported as such. Experimental results on the two most common systems, Al-Si(x)-pSi and ITO-SiO(x)-pSi (ITO designates indium-tin-oxide) are presented to support a model where tunnel current through the

J. Shewchun; D. Burk; M. B. Spitzer

1980-01-01

330

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

331

Solar Coronal Cells as Seen by STEREO  

NASA Video Gallery

The changes of a coronal cell region as solar rotation carries it across the solar disk as seen with NASA's STEREO-B spacecraft. The camera is fixed on the region (panning with it) and shows the pl...

332

Interdigitated back contact solar cells. Annual report  

Microsoft Academic Search

The interdigitated back-contact solar cell (IBC cell) has been shown to possess a number of advantages for silicon solar cells, which operate at high concentration. The purpose of the present program is to support the Sandia Laboratory effort to optimize the IBC cell. A detailed discussion of the factors which need to be considered in the analysis of semiconducting devices

M. S. Lundstrom; R. J. Schwartz

1980-01-01

333

Current status of silicon solar cell technology  

Microsoft Academic Search

In quest of higher efficiency, major progress has occurred in solar cell technology during the last five years. In this period cell efficiency has climbed about 50 percent. Technical approaches leading to increased output include back surface fields (n+-p-p+structures), shallow junctions, improved antireflection coatings, surface texturizing, and fine grid patterns on the cell surface. The status of current solar cell

H. W. Jr

1975-01-01

334

Double-Sided Solar Cell Package.  

National Technical Information Service (NTIS)

A solar cell array for terrestrial use is described. The solar cell package consists of a double sided photovoltaic cell having a metallized P contact and N contact provided on opposite faces of the cell; a transparent tubular body forming a transparent e...

B. Shelpuk

1978-01-01

335

Zinc-, copper- and cadmium-binding protein in Ehrlich ascites tumour cells.  

PubMed Central

The properties of Ehrlich ascites tumour cells exposed in vivo to cadmium were investigated as a function of the zinc status of the host animals. Tumour-cell growth was inhibited by cadmium in both zinc-sufficient and zinc-deficient animals. However, cells in zinc-sufficient tumours accumulate much less cadmium than those in deficient tumours. The subcellular distributions of cadmium and zinc do not depend on zinc status. Cadmium and zinc are bound to a low-molecular-weight protein with properties similar to metallothionein. Without exposure to cadmium, a zinc- and copper-binding protein is still present that behaves like a metallothionein. This protein can rapidly bind cadmium added to Ehrlich cells in vitro. It is shown that the zinc- and copper-binding protein contains free thiol groups. Ehrlich cells isolated from cadmium-treated animals are viable and show normal incorporation of uridine into RNA, but the cellular uptake of thymidine and its incorporation into DNA are inhibited.

Koch, J; Wielgus, S; Shankara, B; Saryan, L A; Shaw, C F; Petering, D H

1980-01-01

336

Silicon solar cell fabrication technology  

NASA Technical Reports Server (NTRS)

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

Stafsudd, O. M.

1979-01-01

337

Three-junction solar cell  

DOEpatents

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

Ludowise, Michael J. (Cupertino, CA) [Cupertino, CA

1986-01-01

338

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

339

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, Sébastien; Garnier, Jérôme; Gergaud, Patrice; Artús, Lluis; Michallon, Jérôme; Rapenne, Laetitia; Appert, Estelle; Kaminski-Cachopo, Anne

2014-05-01

340

Nanosized zinc oxide induces toxicity in human lung cells.  

PubMed

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

341

V-ATPase dysfunction under excess zinc inhibits Arabidopsis cell expansion.  

PubMed

Although zinc is an essential micronutrient for all living organisms, zinc is harmful to cells at high levels. In the presence of excess zinc, plants exhibit several major symptoms, including root growth inhibition, abnormal root hair morphology and chlorosis. To dissect the molecular mechanisms underlying the effects of excess zinc on plant cells, we used aniTRA Q-based quantitative proteomics approach to analyze the microsomal protein profiles of Arabidopsis roots from wild-type (WT) plants and de-etiolated 3-1 (det3-1), a vacuolar H+ -AT Pase (V-AT Pase) subunit C-defective mutant. A comparative analysis of the iTRA Q data from WT and det3-1 plants exposed to excess zinc suggests that the reduction in V-AT Pase subunit levels and its activity are the cause of the symptoms of zinc toxicity, including the inhibition of cell expansion. Provided that reduced V-AT Pase activity in the trans-Golgi network (TGN) alone can inhibit cell expansion, it is possible that the det3-1 mutant phenotype is caused mainly by a defect in TGN acidification, leading to reduced cell wall component trafficking and cell expansion in the presence of excess zinc. To evaluate the contribution of V-AT Pase activity to vacuolar acidification under excess zinc, the vacuolar pH was measured. Our results indicate clear alkalinization of deep cell vacuoles treated with 300 ?M ZnSO4. PMID:21847017

Fukao, Yoichiro; Ferjani, Ali

2011-09-01

342

Effect of enlarged glutathione on zinc-mediated toxicity in lung-derived cell lines.  

PubMed

Zinc-mediated toxicity has been linked to cellular glutathione content in isolated cells. In addition, treatment of alveolar epithelial type II cells with glucocorticoids diminishes cellular glutathione content, and this is followed by an increase in zinc-mediated toxicity. The question arises whether an increase in glutathione synthesis might decrease zinc-mediated toxicity. For this purpose an administration of 200 micromol/l N-acetyl-L-cysteine (NAC) was given to the cells, while cysteine was used up to 100 micromol/l. Zinc-mediated toxicity was assessed by measuring protein synthesis inhibition and glutathione dependent parameters. De novo synthesis of glutathione was assessed as compared to controls by N-acetyl-D-cysteine (NADC) treatment. Comparing NAC and NADC treatment no differences in zinc-mediated toxicity were found. Furthermore only in one (of three) cell line tested a significant increase in GSH content by NAC as compared to NADC treatment was achieved. But even in this cell line no changes by zinc-mediated toxicity were found. It is concluded that the cell lines tested can use other sources of cys for glutathione synthesis. Furthermore the increased zinc-mediated toxicity due to hydrocortisone was abolished in the alveolar epithelial cell lines by the NADC/NAC treatment. It is therefore discussed that additionally to glutathione some other antioxidative defence mechanisms can influence zinc-mediated toxicity as well. PMID:17084062

Walther, U I; Walther, S C; Temrück, O

2007-04-01

343

Status of multijunction solar cells  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

344

Impaired calcium entry into cells is associated with pathological signs of zinc deficiency.  

PubMed

Zinc is an essential trace element whose deficiency gives rise to specific pathological signs. These signs occur because an essential metabolic function is impaired as the result of failure to form or maintain a specific metal-ion protein complex. Although zinc is a component of many essential metalloenzymes and transcription factors, few of these have been identified with a specific sign of incipient zinc deficiency. Zinc also functions as a structural component of other essential proteins. Recent research with Swiss murine fibroblasts, 3T3 cells, has shown that zinc deficiency impairs calcium entry into cells, a process essential for many cell functions, including proliferation, maturation, contraction, and immunity. Impairment of calcium entry and the subsequent failure of cell proliferation could explain the growth failure associated with zinc deficiency. Defective calcium uptake is associated with impaired nerve transmission and pathology of the peripheral nervous system, as well as the failure of platelet aggregation and the bleeding tendency of zinc deficiency. There is a strong analogy between the pathology of genetic diseases that result in impaired calcium entry and other signs of zinc deficiency, such as decreased and cyclic food intake, taste abnormalities, abnormal water balance, skin lesions, impaired reproduction, depressed immunity, and teratogenesis. This analogy suggests that failure of calcium entry is involved in these signs of zinc deficiency as well. PMID:23674794

O'Dell, Boyd L; Browning, Jimmy D

2013-05-01

345

Development of single cell protectors for sealed silver-zinc cells, phase 1  

Microsoft Academic Search

A single cell protector (SCP) assembly capable of protecting a single silver-zinc (Ag Zn) battery cell was designed, fabricated, and tested. The SCP provides cell-level protection against overcharge and overdischarge by a bypass circuit. The bypass circuit consists of a magnetic-latching relay that is controlled by the high and low-voltage limit comparators. Although designed specifically for secondary Ag-Zn cells, the

M. S. Imamura; R. L. Donovan; J. W. Lear; B. Murray

1976-01-01

346

Investigation of Sustained Arc under Solar Cell  

NASA Astrophysics Data System (ADS)

We have so far studied the sustained arc between solar array strings using solar array coupons. The solar cells are connected electrically in series by interconnectors. The interconnector is conductor and is weld at both backside and top of cells. The solar array paddle undergoes the mechanical stress due to thermal cycles in orbit. This stress may cause the separation of interconnector welding backside of cells. If the interconnector is separated from the cell, the string circuit is opened. However solar cells can generate voltage. If the separated interconnector attached to the cell again, the current can flow. If the path between interconnector and cell is formed by insulated adhesive, sustained arc can occur between the separated interconnector and cell. In this paper, the sustained arc between interconnector and cells was investigated experimentally.

Toyoda, Kazuhiro; Cho, Mengu; Kawakita, Shirou; Takahashi, Masato

347

Zinc sensitizes prostate cancer cells to sorafenib and regulates the expression of Livin.  

PubMed

In prostate carcinogenesis, normal zinc-accumulating epithelial cells are transformed into malignant cells that do not accumulate zinc. Increased levels of zinc have been shown to induce apoptosis through a caspase-dependent mechanism with down-regulated anti-apoptotic proteins in prostate cancer cells. Our previous study showed that, as a member of the inhibitor of apoptosis proteins (IAPs) family, Livin could play an important role in the initiation of human prostate cancer and promote cell proliferation by altering the G1-S cell cycle transition. In the present study, we measured the apoptosis sensitivity of prostate cancer cells to zinc and sorafenib and found that zinc sensitized prostate cancer cells to sorafenib-induced apoptosis. Surprisingly, we also found that, unlike its counterparts Survivin and cIAP2, Livin was not decreased all the time; instead, it was compensatively increased in zinc-mediated apoptosis at 48 h in prostate cancer cells. Our results offer potential treatment combinations that may augment the effect of sorafenib, and also reveal, for the first time, that increased Livin expression may play a role in the early cell death response of prostate cancer cells to zinc. PMID:23435194

Chen, Xiaochi; Che, Xiangyu; Wang, Jianbo; Chen, Feng; Wang, Xuejian; Zhang, Zhiwei; Fan, Bo; Yang, Deyong; Song, Xishuang

2013-05-01

348

Zinc activates NF-?B in HUT78 cells  

Microsoft Academic Search

Zinc is essential for human health, and its deficiency in human beings results in growth failure, immune disorders affecting Th1 functions, decreased interleukin-2 (IL-2) production, and cognitive impairment. Nearly 2000 transcription factors require zinc for their structural integrity; however, it is not known whether cellular zinc deficiency results in any change in activation of any of the transcription factors. Inasmuch

Ananda S. Prasad; Bin Bao; Frances W. J. Beck; Fazlul H. Sarkar

2001-01-01

349

Energy Conversion: Nano Solar Cell  

NASA Astrophysics Data System (ADS)

Problems of fossil-fuel-induced climate change have sparked a demand for sustainable energy supply for all sectors of economy. Most laboratories continue to search for new materials and new technique to generate clean energy at affordable cost. Nanotechnology can play a major role in solving the energy problem. The prospect for solar energy using Si-based technology is not encouraging. Si photovoltaics can produce electricity at 20-30 cslash/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 2.49×10-4 mA/cm2 and an open circuit voltage of 0.45 V under illumination of a projector halogen light at 100 mW/cm2.

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

2009-09-01

350

Colchicine induced intraneuronal free zinc accumulation and dentate granule cell degeneration.  

PubMed

Colchicine has been discovered to inhibit many inflammatory processes such as gout, familial Mediterranean fever, pericarditis and Behcet disease. Other than these beneficial anti-inflammatory effects, colchicine blocks microtubule-assisted axonal transport, which results in the selective loss of dentate granule cells of the hippocampus. The mechanism of the colchicine-induced dentate granule cell death and depletion of mossy fiber terminals still remains unclear. In the present study, we hypothesized that colchicine-induced dentate granule cell death may be caused by accumulation of labile intracellular zinc. 10 ?g kg(-1) of colchicine was injected into the adult rat hippocampus and then brain sections were evaluated at 1 day or 1 week later. Neuronal cell death was evaluated by H&E staining or Fluoro-Jade B. Zinc accumulation and vesicular zinc were detected by N-(6-methoxy-8-quinolyl)-para-toluene sulfonamide (TSQ) staining. To test whether an extracellular zinc chelator can prevent this process, CaEDTA was injected into the hippocampus over a 5 min period with colchicine. To test whether other microtubule toxins also produce similar effects as colchicine, vincristine was injected into the hippocampus. The present study found that colchicine injection induced intracellular zinc accumulation in the dentate granule cells and depleted vesicular zinc from mossy fiber terminals. Injection of a zinc chelator, CaEDTA, did not block the zinc accumulation and neuronal death. Vincristine also produced intracellular zinc accumulation and neuronal death. These results suggest that colchicine-induced dentate granule cell death is caused by blocking axonal zinc flow and accumulation of intracellular labile zinc. PMID:24874779

Choi, Bo Young; Lee, Bo Eun; Kim, Jin Hee; Kim, Hyun Jung; Sohn, Min; Song, Hong Ki; Chung, Tae Nyoung; Suh, Sang Won

2014-07-23

351

New reactions involving the oxidative O-, N-, and C-phosphorylation of organic compounds by phosphorus and phosphides in the presence of metal complexes  

NASA Astrophysics Data System (ADS)

The mechanisms of new catalytic reactions leading to the formation of di-, and tri-alkyl phosphates, di- and tri-alkyl phosphites, phosphoramidites, phosphazenes, phosphines, and phosphine oxides from hydrogen, copper, and zinc phosphides and white and red phosphorus are analysed. The mechanisms of the activation of the reactants by metal complexes and of the reactions involving the oxidative P-O, P-N, and P-C coupling of organic compounds to phosphorus and phosphides are considered. The bibliography includes 124 references.

Dorfman, Ya A.; Aleshkova, M. M.; Polimbetova, G. S.; Levina, L. V.; Petrova, T. V.; Abdreimova, R. R.; Doroshkevich, D. M.

1993-09-01

352

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

353

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

354

Epitaxial thin-film Si solar cells  

Microsoft Academic Search

Most types of thin-film solar cells imply a radical departure from the dominant bulk crystalline Si technology. This is not the case for epitaxial thin-film solar cells. In this technology, a high quality Si layer is deposited epitaxially on a low-cost Si substrate (e.g. cast Upgraded Metallurgical Grade silicon or high-throughput Si ribbons) and processed into a solar cell. This

G. Beaucarne; F. Duerinckx; I. Kuzma; K. Van Nieuwenhuysen; H. J. Kim; J. Poortmans

2006-01-01

355

Potential of amorphous silicon for solar cells  

Microsoft Academic Search

.   This paper reviews recent developments in the field of amorphous-silicon-based thin-film solar cells and discusses potentials\\u000a for further improvements. Creative efforts in materials research, device physics, and process engineering have led to highly\\u000a efficient solar cells based on amorphous hydrogenated silicon. Sophisticated multijunction solar cell designs make use of\\u000a its unique material properties and strongly suppress light induced degradation.

B. Rech; H. Wagner

1999-01-01

356

Dye-sensitized nanocrystalline solar cells  

Microsoft Academic Search

The basic physical and chemical principles behind the dye-sensitized nanocrystalline solar cell (DSC: also known as the Gratzel cell after its inventor) are outlined in order to clarify the differences and similarities between the DSC and conventional semiconductor solar cells. The roles of the components of the DSC (wide bandgap oxide, sensitizer dye, redox electrolyte or hole conductor, counter electrode)

Laurence M. Peter

2007-01-01

357

Solar cell system having alternating current output  

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

358

Search for new solar cell heats up  

SciTech Connect

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

Lipkin, R.

1990-11-05

359

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

360

Early Hematopoietic Zinc Finger Protein Prevents Tumor Cell Recognition by Natural Killer Cells1  

PubMed Central

Early hematopoietic zinc finger/zinc finger protein 521 (EHZF/ZNF521) is a novel zinc finger protein expressed in hematopoietic stem and progenitor cells and is down-regulated during their differentiation. Its transcript is also abundant in some hematopoietic malignancies. Analysis of the changes in the antigenic profile of cells transfected with EHZF cDNA revealed up-regulation of HLA class I cell surface expression. This phenotypic change was associated with an increased level of HLA class I H chain, in absence of detectable changes in the expression of other Ag-processing machinery components. Enhanced resistance of target cells to NK cell-mediated cytotoxicity was induced by enforced expression of EHZF in the cervical carcinoma cell line HeLa and in the B lymphoblastoid cell line IM9. Preincubation of transfected cells with HLA class I Ag-specific mAb restored target cell susceptibility to NK cell-mediated lysis, indicating a specific role for HLA class I Ag up-regulation in the NK resistance induced by EHZF. A potential clinical significance of these findings is further suggested by the inverse correlation between EHZF and MHC class I expression levels, and autologous NK susceptibility of freshly explanted multiple myeloma cells.

La Rocca, Rosanna; Fulciniti, Mariateresa; Lakshmikanth, Tadepally; Mesuraca, Maria; Ali, Talib Hassan; Mazzei, Valerio; Amodio, Nicola; Catalano, Lucio; Rotoli, Bruno; Ouerfelli, Ouathek; Grieco, Michele; Gulletta, Elio; Bond, Heather M.; Morrone, Giovanni; Ferrone, Soldano; Carbone, Ennio

2009-01-01

361

Aligned Si nanowire-based solar cells  

NASA Astrophysics Data System (ADS)

Si nanowires (Si NWs), as one of the fundamental building blocks for nano sciences and technologies, have attracted significant attention recently for solar cell applications, owing to the following: (1) Si NWs can significantly reduce materials consumption, and thus the solar cells fabrication cost; (2) NWs' capability to decouple light trapping and carrier collection, which is critical to achieve high power conversion efficiency. In this paper, recent progress on aligned-Si-NW-based solar cells are reviewed from optical and electrical characteristics to experimental demonstrations. Based on the understanding of each preparation process, the issues regarding the realization of highly efficient Si NW based solar cells are discussed.

Li, Junshuai; Yu, Hongyu; Li, Yali

2011-12-01

362

Laser-assisted solar cell metallization processing  

NASA Technical Reports Server (NTRS)

Laser-assisted processing techniques for producing high-quality solar cell metallization patterns are being investigated, developed, and characterized. The tasks comprising these investigations are outlined.

Rohatgi, A.; Gupta, S.; Mcmullin, P. G.; Palaschak, P. A.

1985-01-01

363

Solar cells using quantum funnels.  

PubMed

Colloidal quantum dots offer broad tuning of semiconductor bandstructure via the quantum size effect. Devices involving a sequence of layers comprised of quantum dots selected to have different diameters, and therefore bandgaps, offer the possibility of funneling energy toward an acceptor. Here we report a quantum funnel that efficiently conveys photoelectrons from their point of generation toward an intended electron acceptor. Using this concept we build a solar cell that benefits from enhanced fill factor as a result of this quantum funnel. This concept addresses limitations on transport in soft condensed matter systems and leverages their advantages in large-area optoelectronic devices and systems. PMID:21827197

Kramer, Illan J; Levina, Larissa; Debnath, Ratan; Zhitomirsky, David; Sargent, Edward H

2011-09-14

364

Indium phosphide\\/cadmium sulfide thin-film solar cells. Quarterly technical progress report No. 1, June 1979August 1979  

Microsoft Academic Search

Cadmium sulfide and InP thin films were prepared by thermal evaporation and planar reactive deposition, respectively. Polycrystalline CdS films up to 10 ..mu..m thick showed absorption losses of less than 10% over the 0.6- to 1.0-..mu..m wavelength range. A threefold increase in lateral grain size was achieved when CdS\\/ITO\\/GLASS structures were partially recrystallized in flowing HâS\\/Ar at 550°C. InP deposited

Zanio

1979-01-01

365

Indium phosphide\\/cadmium sulfide thin-film solar cells. Quarterly technical progress report No. 3, December 1979April 1980  

Microsoft Academic Search

Thin films (approx. 1 ..mu..m thick) and large grains (approx. 40 x 40 ..mu..m) of InP were epitaxially deposited on low-cost recrystallized CdS (RXCdS) substrates at 280°C by planar reactive deposition. At 380°C, a 0.4- to 1.0-..mu..m-thick In-Cd-S transition layer between the InP and the RXCdS degrades the quality of the InP epitaxy. However, p-type InP films were prepared at

Zanio

1980-01-01

366

Indium Phosphide/Cadmium Sulfide Thin-Film Solar Cells. Final Report, May 1979 Through July 1980.  

National Technical Information Service (NTIS)

Thin-film InP/RXCdS/ITO/GLASS devices were prepared by depositing ITO on low-cost glass substrate, depositing CdS on the ITO by thermal evaporation, increasing the CdS lateral grain size by recrystallization, and depositing p-type InP by planar reactive d...

K. Zanio

1980-01-01

367

Parametric study of zinc deposition on porous carbon in a flowing electrolyte cell  

SciTech Connect

X-ray radiography coupled with high resolution optical densitometry, as well as optical and scanning electron microscopy, was employed to study the effect of pivotal zinc deposition parameters on the zinc morphology within a porous C foam electrode. Deposition was carried out in zinc-bromine and zinc-zinc cells with circulating electrolyte. Results on the effects of flow rate, substrate thickness, current density, and electrolyte composition on zinc distribution in the substrate and on its surface are described. This study has shown that in the absence of organi inhibitors, very nonuniform zinc deposition occurs within the porous electrode. This zinc deposition corresponds to the nonuniform primary current distribution dominated by ohmic resistance. This study has led to the conclusions tha high electrolyte flow rates, moderate current densities, and thick foams all aid in producing increasingly uniform zinc deposits. The most beneficial effects on the zinc morphology, however, were obtained by adding to the electrolyt a dendrite inhibitor-solubilizer combination consisting of certain fluorosurfactants and butyrolactone.

Iacovangelo, C.D.; Will, F.G.

1985-04-01

368

GPS patch antenna with photovoltaic solar cells for vehicular applications  

Microsoft Academic Search

This paper describes the application of photovoltaic (PV) solar cells in planar antenna structures. The radiating patch element of a planar antenna is replaced by a solar cell. The original feature of a solar cell (DC current generation) remains, but additionally the cell is now able to receive and transmit electromagnetic waves. Both single solar cells as well as solar

Norbert Henze; Andre Giere; Henning Früchting; Pascal Hofmann

2003-01-01

369

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

370

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

371

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

372

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

373

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

374

Improving Polymer Solar Cell Through Efficient Solar Energy Harvesting  

Microsoft Academic Search

\\u000a In the last few years, several effective approaches have been developed to improve polymer solar cell performance. In this\\u000a chapter, we summarized several of the efforts conducted in UCLA on polymer solar cells, of which each is associated to efficient\\u000a light harvesting. We first discussed effective approaches to improve morphology and nanoscale structure control on the polymer\\u000a active layer through

Hsiang-Yu Chen; Zheng Xu; Gang Li; Yang Yang

2010-01-01

375

Zinc sparks are triggered by fertilization and facilitate cell cycle resumption in mammalian eggs  

PubMed Central

In last few hours of maturation, the mouse oocyte takes up over twenty billion zinc atoms and arrests after the first meiotic division, until fertilization or pharmacological intervention stimulates cell cycle progression towards a new embryo. Using chemical and physical probes, we show that fertilization of the mature, zinc-enriched egg triggers the ejection of zinc into the extracellular milieu in a series of coordinated events termed zinc sparks. These events immediately follow the well-established series of calcium oscillations within the activated egg and are evolutionarily conserved in several mammalian species, including rodents and non-human primates. Functionally, the zinc sparks mediate a decrease in intracellular zinc content that is necessary for continued cell cycle progression, as increasing zinc levels within the activated egg results in the reestablishment of cell cycle arrest at metaphase. The mammalian egg thus uses a zinc-dependent switch mechanism to toggle between metaphase arrest and resumption of the meiotic cell cycle at the initiation of embryonic development.

Kim, Alison M.; Bernhardt, Miranda L.; Kong, Betty Y.; Ahn, Richard W.; Vogt, Stefan; Woodruff, Teresa K.; O'Halloran, Thomas V.

2011-01-01

376

Postnatal development of zinc-containing cells and neuropil in the visual cortex of the mouse  

Microsoft Academic Search

The postnatal development of zinc-containing synaptic boutons and their cells of origin in the visual cortex of a pigmented mouse is described. Two phases can be distinguished. During the early phase zinc-containing neuropil is first apparent by postnatal day 3. By day 7 a light, but distinct neuropil staining sketches the primary and secondary visual cortices. The primary visual area

B. Garrett; L. Slomianka

1992-01-01

377

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

378

Theoretical temperature dependence of solar cell parameters  

NASA Astrophysics Data System (ADS)

A simple formulation has been derived for the temperature dependence of cell parameters for any solar cell material. Detailed calculations have been performed for high-quality monocrystalline GaAs, Si and Ge cells. Preliminary experimental data for GaAs and Si cells are close to the calculated values. In general, the higher the energy gap of a material, the small is the temperature dependence of its solar cell parameters.

Fan, John C. C.

1986-05-01

379

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

380

Matching of multi junction solar cells for solar array production  

Microsoft Academic Search

The current matching of multi junction solar cells determines the most important cell characteristics, such as efficiency and degradation hardness. The evaluation of current-voltage curves under different spectral irradiances enables a quantitative assessment of the device. Especially the variation of one cell's fill factor clearly indicates the shift in the current matching. A minimal fill factor can be observed at

R. Adelhelm; G. La Roche

2000-01-01

381

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

382

Sinterless Formation Of Contacts On Indium Phosphide  

NASA Technical Reports Server (NTRS)

Improved technique makes it possible to form low-resistivity {nearly equal to 10(Sup-6) ohm cm(Sup2)} electrical contacts on indium phosphide semiconductor devices without damaging devices. Layer of AgP2 40 Angstrom thick deposited on InP before depositing metal contact. AgP2 interlayer sharply reduces contact resistance, without need for sintering.

Weizer, Victor G.; Fatemi, Navid S.

1995-01-01

383

Transparent conductive oxides for nano-SIS solar cells  

NASA Astrophysics Data System (ADS)

As a reason of their electrical conductivity and transparency in the visible spectral range transparent conductive oxides (TCOs) are well known as electrodes for OLEDs or LCD displays. Another promising application is a semiconductor-insulator-semiconductor (SIS) solar cell, in which the TCO induces the pn junction and realises a low cost solar cell on crystalline silicon. By using nanostructured silicon interfaces broadband antireflection properties with effective light coupling into the silicon can be achieved. Combined with the SIS concept it is possible to fabricate a low cost and high efficient PV device. For the deposition of thin films of indium tin oxide (ITO) and aluminum doped zinc oxide (AZO) pulsed dc magnetron sputtering is used. The paper presents the surface modification of silicon by inductive coupled plasma (ICP) etching technology, discusses the influence of different TCO materials to the device, and analyses the optical and structural properties of the cells. Furthermore, the solar cell performance under AM1.5G illumination will be shown.

Füchsel, K.; Bingel, A.; Kaiser, N.; Tünnermann, A.

2011-04-01

384

Transparent Conductors and Barrier Layers for Thin Film Solar Cells:  

SciTech Connect

This report describes the research undertaken to increase the efficiency of thin-film solar cells based on amorphous silicon in the so-called''superstrate structure'' (glass front surface/transparent electrically conductive oxide (TCO)/pin amorphous silicon/metal back electrode). The TCO layer must meet many requirements: high optical transparency in the wavelength region from about 350 to 900 nm, low electrical sheet resistance, stability during handling and deposition of the subsequent layers and during use, a textured (rough) surface to enhance optical absorption of red and near-infrared light, and low-resistance electrical contact to the amorphous silicon p-layer. Fluorine-doped tin oxide has been the TCO used in most commercial superstrate amorphous silicon cells. Fluorine-doped zinc oxide (ZnO:F) was later shown to be even more transparent than fluorine-doped tin oxide, as well as being more resistant to the strongly reducing conditions encountered during the deposition of amorphous silicon. Solar cells based on ZnO:F showed the expected higher currents, but the fill factors were lower than standard cells grown on tin oxide, resulting in no consistent improvement in efficiency. This problem was recently mitigated by using a new proprietary p/buffer layer combination developed at BP Solar.

Gordon, R. G.; Broomhall-Dillard, R.; Liu, X.; Pang, D.; Barton, J.

2001-12-01

385

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

386

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

387

Targeted chromosomal deletions in human cells using zinc finger nucleases  

PubMed Central

We present a novel approach for generating targeted deletions of genomic segments in human and other eukaryotic cells using engineered zinc finger nucleases (ZFNs). We found that ZFNs designed to target two different sites in a human chromosome could introduce two concurrent DNA double-strand breaks (DSBs) in the chromosome and give rise to targeted deletions of the genomic segment between the two sites. Using this method in human cells, we were able to delete predetermined genomic DNA segments in the range of several-hundred base pairs (bp) to 15 mega-bp at frequencies of 10?3 to 10?1. These high frequencies allowed us to isolate clonal populations of cells, in which the target chromosomal segments were deleted, by limiting dilution. Sequence analysis revealed that many of the deletion junctions contained small insertions or deletions and microhomologies, indicative of DNA repair via nonhomologous end-joining. Unlike other genome engineering tools such as recombinases and meganucleases, ZFNs do not require preinsertion of target sites into the genome and allow precise manipulation of endogenous genomic scripts in animal and plant cells. Thus, ZFN-induced genomic deletions should be broadly useful as a novel method in biomedical research, biotechnology, and gene therapy.

Lee, Hyung Joo; Kim, Eunji; Kim, Jin-Soo

2010-01-01

388

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.

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

1969-01-01

389

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

390

Zinc transport by respiratory epithelial cells and interaction with iron homeostasis  

Microsoft Academic Search

Despite recurrent exposure to zinc through inhalation of ambient air pollution particles, relatively little information is\\u000a known about the homeostasis of this metal in respiratory epithelial cells. We describe zinc uptake and release by respiratory\\u000a epithelial cells and test the postulate that Zn2+ transport interacts with iron homeostasis in these same cells. Zn2+ uptake after 4 and 8 h of exposure

Zhongping Deng; Lisa A. Dailey; Joleen Soukup; Jacqueline Stonehuerner; Judy D. Richards; Kimberly D. Callaghan; Funmei Yang; Andrew J. Ghio

2009-01-01

391

Multifolded polymer solar cells on flexible substrates  

NASA Astrophysics Data System (ADS)

Arrays of reflective multijunction polymer solar cell were demonstrated by folding four separated cells fabricated on a single plastic substrate using conducting polymer poly(3, 4-ethylene-dioxythiophene):polystyrenesulfonate as an anode. The combination of flexible substrate and polymer solar cells (PSCs) makes the construction of multifolded PSCs on one substrate possible. The power conversion efficiency (PCE) of the multifolded reflective PSCs was enhanced by 62%+/-12% with the folded opening angle of 30° compared to the planar cells. In series connection of four solar cells, an open-circuit voltage (Voc) of 3.65 V was obtained.

Zhou, Yinhua; Zhang, Fengling; Tvingstedt, Kristofer; Tian, Wenjing; Inganäs, Olle

2008-07-01

392

Theoretical Investigation on Heterojunction Solar Cell.  

National Technical Information Service (NTIS)

The study of thin film solar cells has proved that the surface is rough. A two-dimensional method based on the integral equation technique to analyse thin film solar cells has been developed by DeMey et al. In this paper we present our analysis of a thin ...

K. Prema K. Geetha

1986-01-01

393

Infrared-Controlled Welding of Solar Cells  

NASA Technical Reports Server (NTRS)

Proposed apparatus for welding large arrays of solar cells to flexible circuit substrates would sense infrared emission from welding spot. Emission would provide feedback for control of welding heat. Welding platform containing optical fibers moves upward through slots in movable holding fixture to contact solar cells. Fibers pick up infrared radiation from weld area.

Paulson, R.; Finnell, S. E.; Decker, H. J.; Hodor, J. R.

1982-01-01

394

Stability\\/degradation of polymer solar cells  

Microsoft Academic Search

Polymer and organic solar cells degrade during illumination and in the dark. This is in contrast to photovoltaics based on inorganic semiconductors such as silicon. Long operational lifetimes of solar cell devices are required in real-life application and the understanding and alleviation of the degradation phenomena are a prerequisite for successful application of this new and promising technology. In this

Mikkel Jørgensen; Kion Norrman; Frederik C. Krebs

2008-01-01

395

High-voltage vertical multijunction solar cell  

Microsoft Academic Search

The vertical multijunction solar cell with covering lens is a photovoltaic device which promises efficiencies greater than that predicted under ideal conditions for any other structure. The mathematical analysis presented here illustrates this statement. In addition the structure described here is capable of a high-voltage output for small solar cell dimensions, a feature which makes this device attractive for many

R. J. Soukup

1976-01-01

396

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

397

Early hematopoietic zinc finger protein-zinc finger protein 521: a candidate regulator of diverse immature cells.  

PubMed

The early hematopoietic zinc finger protein/zinc finger protein 521 (EHZF/ZNF521) is a recently identified, 1131 amino-acid-long nuclear factor that contains 30 zinc fingers distributed in clusters throughout its sequence. A 13-AA motif, that binds to components of the nuclear remodelling and histone deacetylation (NuRD) complex and is conserved in several trascriptional co-repressors, is located at the amino-terminal end of the molecule. EHZF/ZNF521 expression is high in the most immature cells of the haematopoietic system and declines with differentiation. Its transcript is also abundant in brain, particularly in the cerebellum. Its murine counterpart, Evi3/Zfp521, is enriched in haematopoietic and neural stem cells, in cerebellar granule neuron precursors and in the developing striatum. Enforced expression of EHZF/ZNF521 in haematopoietic progenitors results in their expansion and in inhibition of differentiation. EHZF/ZNF521 is a member of the BMP signalling pathway and an inhibitor of the transcription factor OLF1/EBF1, implicated in the differentiation of neural progenitors and in the specification of the B-cell lineage. EHZF expression is observed in most acute myelogenous leukaemias and is particularly high in those with rearrangements of the MLL gene, where EHZF may contribute to the leukaemic phenotype. EHZF/ZNF521 is also abundant in medulloblastomas and other brain tumours. Taken together, the data available suggest a possible role for this factor in development, stem cell regulation and oncogenesis. PMID:17543573

Bond, Heather M; Mesuraca, Maria; Amodio, Nicola; Mega, Tiziana; Agosti, Valter; Fanello, Delia; Pelaggi, Daniela; Bullinger, Lars; Grieco, Michele; Moore, Malcolm A S; Venuta, Salvatore; Morrone, Giovanni

2008-01-01

398

Iron and zinc bioavailability in Caco-2 cells: influence of caseinophosphopeptides.  

PubMed

A study has been made of the influence of two pools of caseinophosphopeptides (CPPs) obtained from ?(s)- and ?-casein (CN) fractions, and of three specific CPPs (?-CN(1-25)4P, ?(s1)-CN(64-74)4P and ?(s2)-CN(1-19)4P), on iron bioavailability (ferritin synthesis) and zinc bioavailability (retention, transport and uptake of zinc) in Caco-2 cells. ?-CPP and ?-CPP pools did not improve ferritin synthesis, but the three specific CPPs showed an increase in ferritin synthesis in Caco-2 cells versus iron sulphate, ?-CN(1-25)4P being the most effective. In relation to zinc bioavailability, ?-CPPs, ?-CPPs, ?(s1)-CN(64-74)4P and ?-CN(1-25)4P increased zinc uptake. However, this increase was of the same order as the increase due to the presence of zinc sulphate. PMID:23411246

García-Nebot, María José; Barberá, Reyes; Alegría, Amparo

2013-06-01

399

Zinc adaptation and resistance to cadmium toxicity in mammalian cells: molecular insight by proteomic analysis.  

PubMed

To identify proteins involved in cellular adaptive responses to zinc, a comparative proteome analysis between a previously developed high zinc- and cadmium-resistant human epithelial cell line (high zinc-resistant HeLa cells, HZR) and the parental HeLa cells has been carried out. Differentially produced proteins included cochaperones, proteins associated with oxido-reductase activities, and ubiquitin. Biochemical pathways to which these proteins belong were probed for their involvement in the resistance of both cell lines against cadmium toxicity. Among ER stressors, thapsigargin sensitized HZR cells, but not HeLa cells, to cadmium toxicity more acutely than tunicamycin, implying that these cells heavily relied on proper intracellular calcium distribution. The similar sensitivity of both HeLa and HZR cells to inhibitors of the proteasome, such as MG-132 or lactacystin, excluded improved proteasome activity as a mechanism associated with zinc adaptation of HZR cells. The enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD) was overproduced in HZR cells as compared to HeLa cells. It transforms HPP to homogentisate in the second step of tyrosine catabolism. Inhibition of HPPD decreased the resistance of HZR cells against cadmium, but not that of HeLa cells, suggesting that adaptation to zinc overload and increased HPP removal are linked in HZR cells. PMID:18452231

Rousselet, Estelle; Martelli, Alain; Chevallet, Mireille; Diemer, Hélène; Van Dorsselaer, Alain; Rabilloud, Thierry; Moulis, Jean-Marc

2008-06-01

400

High-efficiency concentrator silicon solar cells  

Microsoft Academic Search

This report presents results from extensive process development in high-efficiency Si solar cells. An advanced design for a 1.56-cm(sup 2) cell with front grids achieved 26 percent efficiency at 90 suns. This is especially significant since this cell does not require a prismatic cover glass. New designs for simplified backside-contact solar cells were advanced from a status of near-nonfunctionality to

R. A. Sinton; A. Cuevas; R. R. King; R. M. Swanson

1990-01-01

401

Flexible solid-state dye solar cells  

Microsoft Academic Search

The cell structure concepts and materials to build solid-state dye solar cells based on nanocristalline titanium oxide and an organic hole conductor were investigated. The substrate cell is based on a metal foil and a semi-transparent gold window on top of the cell structure and the superstrate cell is deposited on ITO coated polymer foil replacing the traditional conductive glass

Toby B. Meyer; Andreas F. Meyer; Daniel Ginestoux

2002-01-01

402

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

403

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

PubMed Central

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

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

2004-01-01

404

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

405

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

406

Industrial-hygiene survey of the zinc cell room, anode room, and zinc-casting area, Bunker Hill Company Kellogg, Idaho  

Microsoft Academic Search

A study was begun at the Bunker Hill Company at the request of the state mine inspector to determine possible health hazards to workers at the smelter and zinc refinery located in Kellogg, Idaho. In-depth surveys were conducted of the lead anode room, the cell room, the zinc casting department, and the old roaster building and roaster number 5 building.

1971-01-01

407

Zinc enhances the expression of interleukin-2 and interleukin-2 receptors in HUT78 cells by way of NF-?B activation  

Microsoft Academic Search

Production of interleukin (IL)-2 is decreased in zinc-deficient human beings, and zinc is essential to IL-2-mediated T-cell activation. We used a human Th0 malignant lymphoblastoid cell line, HUT-78, to study the effect of zinc on IL-2 production in PHA\\/PMA activated T-cells. In zinc-deficient cells, the gene expression of IL-2 was decreased by 50% compared with that in zinc-sufficient cells. The

Ananda S. Prasad; Bin Bao; Frances W. J. Beck; Fazlul H. Sarkar

2002-01-01

408

Tandem photovoltaic solar cells and increased solar energy conversion efficiency  

NASA Technical Reports Server (NTRS)

Tandem photovoltaic cells, as proposed by Jackson (1955) to increase the efficiency of solar energy conversion, involve the construction of a system of stacked p/n homojunction photovoltaic cells composed of different semiconductors. It had been pointed out by critics, however, that the total power which could be extracted from the cells in the stack placed side by side was substantially greater than the power obtained from the stacked cells. A reexamination of the tandem cell concept in view of the development of the past few years is conducted. It is concluded that the use of tandem cell systems in flat plate collectors, as originally envisioned by Jackson, may yet become feasible as a result of the development of economically acceptable solar cells for large scale terrestrial power generation.

Loferski, J. J.

1976-01-01

409

Differential radioprotection of bone marrow and tumour cells by zinc aspartate.  

PubMed

The radioprotector zinc aspartate did not inhibit the radiotherapeutic effect of gamma rays on human tumours grown as xenografts in immunosuppressed mice, while aminothiol radioprotectors afforded a slight inhibition. On the other hand, zinc aspartate significantly reduced the fall in the haematocrit and numbers of thrombocytes, erythrocytes and leucocytes caused by irradiation, indicating a sparing effect on bone marrow precursors of peripheral blood cells. This differential protection of neoplastic and normal cells may be of considerable benefit in clinical cancer radiotherapy, provided that zinc aspartate is better tolerated and has a more favourable therapeutic index in humans than aminothiol radioprotectors. PMID:3370431

Floersheim, G L; Chiodetti, N; Bieri, A

1988-06-01

410

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.

Tian, Jianjun; Cao, Guozhong

2013-01-01

411

Dye-sensitized Solar Cells for Solar Energy Harvesting  

NASA Astrophysics Data System (ADS)

Dye-sensitized solar cells (DSSCs) also known as Gratzel cells, have attracted the interests of researchers to a great extent because of its cost effective and easy manufacturing process without involving highly sophisticated lithographic technique and high cost raw materials as usually seen in conventional solar cell. Based on simple photo-electrochemical process, it has got immense potential in converting solar energy to electrical power in remote and desert area where the supply of conventional power is not possible. The overall peak power-production efficiency of dye-sensitized solar cells has been reported around 11 percent, so they are best suited to low-density applications and the price-to-performance ratio obtained through these solar cells is superior to others. DSSCs have ability to absorb even diffused sunlight and therefore work in cloudy whether as well without much impact over the efficiency. The present communication deals with a review of our work on DSSCs wherein we have used cost effective natural dyes/pigments as a sensitizer of nc-TiO2 and discussed about various key factors affecting the conversion efficiency of DSSC.

Roy, M. S.; Deol, Y. S.; Kumar, Manish; Prasad, Narottam; Janu, Yojana

2011-10-01

412

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, Jörg Rudolf; Zentek, Jürgen; Pieper, Robert

2013-08-01

413

Histiocytic and dendritic reticulum cells shown by a zinc iodide-osmium technique.  

PubMed Central

Structures corresponding to histiocytic and dendritic reticulum cells have been shown in human tonsillar tissue, "reactive" lymph nodes and spleens by means of a zinc iodide-osmium technique. These cell types have been shown in various locations in these tissues using paraffin and resin embedded sections produced after fixation/staining of the tissue in zinc iodide-osmium. The quality of morphology attained by this procedure is much improved compared with the demonstration of the two cell types by means of alpha-naphthyl acetate esterase reactions performed on frozen sections. The zonal architecture of the lymphoid follicle is emphasised by this technique. In lymph nodes, sinus lining cells are also shown. Lymphoid cells, polymorphs, fibroblasts, and endothelial cells are negative with the zinc iodide-osmium method. In addition, interdigitating cells are not stained. The results of this procedure are compared with those with those of other methods for the demonstration of histiocytic and dendritic reticulum cells. Images

Crocker, J; Hopkins, M

1984-01-01

414

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

415

Profiling of zinc altered gene expression in human prostate normal versus cancer cells: a time course study  

PubMed Central

We have demonstrated that zinc exposure induces apoptosis in human prostate cancer cells (PC-3) and benign hyperplasia cells (BPH), but not in normal prostate cells (HPR-1). However, the mechanisms underlying the effects of zinc on prostate cancer cell growth and zinc homeostasis remain unclear. To explore the zinc effect on gene expression profiles in normal (HPR-1) and malignant prostate cells (PC-3), we conducted a time course study of Zn treatment with microarray analysis. Microarray data were evaluated and profiled using computational approach for the primary and secondary data analyses. Final analyses were focused on the genes: 1. highly sensitive to zinc, 2. associated with zinc homeostasis, i.e. metallothioneins (MTs), solute zinc carriers (ZIPs) and zinc exporters (ZnTs), 3. relevant to several oncogenic pathways. Zinc-mediated mRNA levels of MT isotypes were further validated by semi-quantitative RT-PCR. Results showed that zinc effect on genome-wide expression patterns was cell type specific, and zinc appeared to have mainly down-regulatory effects on thousands of genes (1,953 in HPR-1; 3,534 in PC-3) with a threshold of ±2.5-fold, while fewer genes were up-regulated (872 in HPR-1; 571 in PC-3). The patterns of zinc effect on functional MT genes’ expression provided evidence for the cell-type dependent zinc accumulation and zinc-induced apoptosis in prostate cells. In PC-3 cells, zinc significantly up-regulated the expression of MT-1 isotypes -J and -M, denoted previously as “non-functional” MT genes, and now a depictive molecular structure of MT-1J was proposed. Examination of genes involved in oncogenic pathways indicated that certain genes, e.g. Fos, Akt1, Jak3 and PI3K were highly regulated by zinc with cell type specificity. This work provided an extensive database on zinc related prostate cancer research. The strategy of data analysis was devoted to find genes highly sensitive to Zn, and the genes associated with zinc accumulation and zinc-induced apoptosis. The results indicate that zinc regulation of gene expression is cell-type specific, and MT genes play important roles in prostate malignancy.

Lin, Shu-fei; Wei, Hua; Maeder, Dennis; Franklin, Renty B.; Feng, Pei

2010-01-01

416

Pulsed Solar Simulator for Electrical Performance Tests of Space Solar Cells/Arrays.  

National Technical Information Service (NTIS)

A pulsed xenon solar simulator, designed to cope with future measurement problems with advanced solar cells and solar cell arrays, is described. The simulator, consisting of a flash lamp, a power supply, and an operator console, is capable of illuminating...

W. Lukschal A. P. Robben

1989-01-01

417

Development of multijunction thin film solar cells  

Microsoft Academic Search

Due to the possibility of band gap engineering in Cu(In,Ga)Se2 (CIGS) absorbers and the spectral tunability of dye-sensitized solar cells (DSCs) with suitable choice of the sensitizer, this combination of solar cells could be ideal for the construction of dual junction photovoltaic devices. Factors for performance limitations of mechanically stacked tandem cells have been identified and alternative remedies are developed

S. Seyrling; S. Bucheler; A. Chirila; J. Perrenoud; S. Wenger; T. Nakada; M. Gratzel; A. N. Tiwari

2009-01-01

418

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

419

Orienting and Applying Flux to Solar Cells  

NASA Technical Reports Server (NTRS)

Solar cells are oriented and fluxed automatically at first work station along solar-array assembly line. In under 2 seconds rotary drive rotates cell into proper position for applying solder flux to bus pad on collector side. When contact bus pad is in correct position, capstan drive is disengaged, and vacuum holddown beneath cell is turned on. Flux system lowers and applies preset amount of solder flux to bus pad. Two interconnect tabs are soldered to fluxed areas.

Feder, H.; Frasch, W.

1982-01-01

420

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

421

Comprehensive silicon solar-cell computer modeling  

NASA Technical Reports Server (NTRS)

A comprehensive silicon solar cell computer modeling scheme was developed to perform the following tasks: (1) model and analysis of the net charge distribution in quasineutral regions; (2) experimentally determined temperature behavior of Spire Corp. n+pp+ solar cells where n+-emitter is formed by ion implantation of 75As or 31P; and (3) initial validation results of computer simulation program using Spire Corp. n+pp+ cells.

Lamorte, M. F.

1984-01-01

422

Dielectric films for Si solar cell applications  

Microsoft Academic Search

Thin films of many dielectric materials have been used in the past for fabrication of solar cells and as a part of their device\\u000a structure. However, current efforts to reduce solar cell costs in commercial production have led to simplification of cell\\u000a design and fabrication. Use of self-aligning techniques has obviated the need for photolithography and conventional masking\\u000a with dielectric

Bhushan Sopori

2005-01-01

423

Single-nanowire Si solar cells  

Microsoft Academic Search

Solar cells based on arrays of CVD-grown Si nano- or micro-wires are being considered as a potentially low-cost route to implementing a vertical multijunction cell design via radial p-n junctions. This geometry has been predicted to enable efficiencies competitive with planar multicrystalline Si designs, while reducing the materials and processing costs of solar cell fabrication [1]. To further assess the

M. D. Kelzenberg; D. B. Turner-Evans; B. M. Kayes; M. A. Filler; M. C. Putnam; N. S. Lewis; H. A. Atwater

2008-01-01

424

High-voltage solar-cell chip  

Microsoft Academic Search

Integrated circuit technology has been successfully applied to the design and fabrication of 0.5 x 0.5-cm planar multijunction solar-cell chips. Each of these solar cells consisted of six voltage-generating unit cells monolithically connected in series and fabricated on a 75-micron-thick, p-type, single crystal, silicon substrate. A contact photolithic process employing five photomask levels together with a standard microelectronics batch-processing technique

V. J. Kapoor; G. J. Valco; G. G. Skebe; J. C. Evans Jr.

1985-01-01

425

Assessing Possibilities & Limits for Solar Cells  

Microsoft Academic Search

What are the solar cell efficiencies that we can strive towards? We show here\\u000athat several simple criteria, based on cell and module performance data, serve\\u000ato evaluate and compare all types of today's solar cells. Analyzing these data\\u000aallows to gauge in how far significant progress can be expected for the various\\u000acell types and, most importantly from both

Pabitra K. Nayak; Juan Bisquert; David Cahen

2011-01-01

426

Silicon solar cells improved by lithium doping  

NASA Technical Reports Server (NTRS)

Results of conference on characteristics of lithium-doped silicon solar cells and techniques required for fabrication indicate that output of cells has been improved to point where cells exhibit radiation resistance superior to those currently in use, and greater control and reproducibility of cell processing have been achieved.

Berman, P. A.

1970-01-01

427

Electron irradiation of modern solar cells  

NASA Technical Reports Server (NTRS)

A number of modern solar cell types representing 1976 technology (as well as some older types) were irradiated with 1 MeV electrons (and a limited number with 2 MeV electrons and 10 MeV protons). After irradiation, the cells were annealed, with I-V curves measured under AMO at 30 C. The purpose was to provide data to be incorporated in the revision of the solar cell radiation handbook. Cell resistivities ranged from 2 to 20 ohm-cm, and cell thickness from 0.05 to 0.46 mm. Cell types examined were conventional, shallow junction, back surface field (BSF), textured, and textured with BSF.

Anspaugh, B. E.; Miyahira, T. F.

1977-01-01

428

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 NP–induced 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.

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

429

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

430

Teachers' Domain: Inside a Solar Cell  

NSDL National Science Digital Library

This interactive Flash tutorial shows how photovoltaic cells in solar panels convert sunlight into electrical current. It provides a close-up look at each layer of the basic solar panel, with particular emphasis on how electrons cross over the junction that joins the two silicon layers in the cell. When the concentration of negative and positive charge between the two layers reaches equilibrium, an electric field is produced -- the solar cell is ready to capture photons. Teachers' Domain is a collection of more than 1,000 free educational resources compiled by researchers and experienced teachers to promote the use of digital resources in the classroom.

2012-08-21

431

Temperature coefficients of multijunction solar cells  

NASA Technical Reports Server (NTRS)

Temperature coefficients measured in solar simulators with those measured under AM0 solar illumination are compared to illustrate the challenges in making these measurements. It is shown that simulator measurements of the short-circuit current (delta Jsc/delta T) are inaccurate due to the mismatch between the solar spectrum and the simulators at the bandgaps of the solar cells. Especially susceptible to error is the delta Jsc/delta T of cells which are components in monolithic multijunction solar cells, such as GaAs filtered by 1.93-eV AlGaAs, which has an AM0 coefficient of 6.82 micro-A/sq cm/deg C, compared to a Xenon simulator coefficient of 22.2 micro-A/sq cm/deg C.

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

1990-01-01

432

Enhancement of oxygen vacancies and solar photocatalytic activity of zinc oxide by incorporation of nonmetal  

SciTech Connect

B-doped ZnO and N-doped ZnO powders have been synthesized by mechanochemical method and characterized by TG-DTA, XRD, SEM-EDX, XPS, UV-visible and photoluminescence (PL) spectra. X-ray diffraction data suggests the hexagonal wurtzite structure for modified ZnO crystallites and the incorporation of nonmetal expands the lattice constants of ZnO. The room temperature PL spectra suggest more number of oxygen vacancies exist in nonmetal-doped ZnO than that of undoped zinc oxide. XPS analysis shows the substitution of some of the O atoms of ZnO by nonmetal atoms. Solar photocatalytic activity of B-doped ZnO, N-doped ZnO and undoped ZnO was compared by means of oxidative photocatalytic degradation (PCD) of Bisphenol A (BPA). B-doped ZnO showed better solar PCD efficiency as compare to N-doped ZnO and undoped ZnO. The PCD of BPA follows first order reaction kinetics. The detail mechanism of PCD of Bisphenol A was proposed with the identification of intermediates such as hydroquinone, benzene-1,2,4-triol and 4-(2-hydroxypropan-2-yl) phenol. - Graphical Abstract: B-doped ZnO and N-doped ZnO synthesized by mechanochemical method were characterized by various techniques. Solar photocatalytic degradation of Bisphenol-A is in the order of B-ZnO>N-ZnO>ZnO. Highlights: Black-Right-Pointing-Pointer B-doped ZnO and N-doped ZnO powders have been synthesized by mechanochemical method. Black-Right-Pointing-Pointer PL spectra suggest oxygen vacancies are in order of B-doped ZnO>N-doped ZnO>ZnO. Black-Right-Pointing-Pointer Solar PCD efficiency is in order of B-doped ZnO>N-doped ZnO>ZnO for Bisphenol A.

Patil, Ashokrao B. [Department of Chemistry, University of Pune, Ganeshkhind, Pune 411007 (India); Patil, Kashinath R. [Center for Materials Characterization, National Chemical Laboratory, Pune 411008 (India); Pardeshi, Satish K., E-mail: skpar@chem.unipune.ac.in [Department of Chemistry, University of Pune, Ganeshkhind, Pune 411007 (India)

2011-12-15

433

Alternative approaches for low temperature front surface passivation of interdigitated back contact silicon heterojunction solar cell  

Microsoft Academic Search

In this work, we investigated two alternative approaches for the front surface passivation of interdigitated back contact silicon heterojunction (IBC-SHJ) solar cells: (1) with plasma enhanced chemical vapor deposited (PEVCD) a-Si-based stack structure consisting of a-Si:H\\/a-SiNx:H\\/a-SiC:H, and (2) with physical vapor deposited (PVD) zinc sulfide (ZnS) film. The processing temperatures for both the approaches are under 300°C. Effective surface recombination

Brent Shu; Ujjwal Das; Jesse Appel; Brian McCandless; Steven Hegedus; Robert Birkmire

2010-01-01

434

Water and oxygen induced degradation of small molecule organic solar cells  

Microsoft Academic Search

Small molecule organic solar cells were studied with respect to water and oxygen induced degradation by mapping the spatial distribution of reaction products in order to elucidate the degradation patterns and failure mechanisms. The active layers consist of a 30nm bulk heterojunction formed by the donor material zinc-phthalocyanine (ZnPc) and the acceptor material Buckminsterfullerene (C60) followed by 30nm C60 for

Martin Hermenau; Moritz Riede; Karl Leo; Suren A. Gevorgyan; Frederik C. Krebs; Kion Norrman

2011-01-01

435

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

436

Mechanism of hydrodenitrogenation on phosphides and sulfides.  

PubMed

The mechanism of hydrodenitrogenation (HDN) of 2-methylpiperidine was studied over a silica-supported nickel phosphide catalyst (Ni2P/SiO2, Ni/P = 1/2) and a commercial Ni-Mo-S/Al2O3 catalyst in a three-phase trickle-bed reactor operated at 3.1 MPa and 450-600 K. Analysis of the product distribution as a function of contact time indicated that the reaction proceeded in both cases predominantly by a substitution mechanism, with a smaller contribution of an elimination mechanism. Fourier transform infrared spectroscopy (FTIR) of the 2-methylpiperidine indicated that at reaction conditions a piperidinium ion intermediate was formed on both the sulfide and the phosphide. It is concluded that the mechanism of HDN on nickel phosphide is very similar to that on sulfides. The mechanism on the nickel phosphide was also probed by comparing the reactivity of piperidine and several of its derivatives in the presence of 3000 ppm S. The relative elimination rates depended on the structure of the molecules, and followed the sequence: 4-methylpiperidine approximately piperidine > 3-methylpiperidine > 2,6-dimethylpiperidine > 2-methylpiperidine. [Chemical structure: see text] This order of reactivity was not dependent on the number of alpha-H or beta-H atoms in the molecules, ruling out their reaction through a single, simple mechanism. It is likely that the unhindered piperidine molecules reacted by an S(N)2 substitution process and the more hindered 2,6-dimethylpiperidine reacted by an E2 elimination process. PMID:16851202

Oyama, S Ted; Lee, Yong-Kul

2005-02-17

437

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. Mol Cancer Ther; 13(5); 1369-81. ©2014 AACR. PMID:24634414

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

2014-05-01

438

Ethambutol-induced toxicity is mediated by zinc and lysosomal membrane permeabilization in cultured retinal cells  

SciTech Connect

Ethambutol, an efficacious antituberculosis agent, can cause irreversible visual loss in a small but significant fraction of patients. However, the mechanism of ocular toxicity remains to be established. We previously reported that ethambutol caused severe vacuole formation in cultured retinal cells, and that the addition of zinc along with ethambutol aggravated vacuole formation whereas addition of the cell-permeable zinc chelator, N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN), reduced vacuole formation. To investigate the origin of vacuoles and to obtain an understanding of drug toxicity, we used cultured primary retinal cells from newborn Sprague-Dawley rats and imaged ethambutol-treated cells stained with FluoZin-3, zinc-specific fluorescent dye, under a confocal microscope. Almost all ethambutol-induced vacuoles contained high levels of labile zinc. Double staining with LysoTracker or MitoTracker revealed that almost all zinc-containing vacuoles were lysosomes and not mitochondria. Intracellular zinc chelation with TPEN markedly blocked both vacuole formation and zinc accumulation in the vacuole. Immunocytochemistry with antibodies to lysosomal-associated membrane protein-2 (LAMP-2) and cathepsin D, an acid lysosomal hydrolase, disclosed lysosomal activation after exposure to ethambutol. Immunoblotting after 12 h exposure to ethambutol showed that cathepsin D was released into the cytosol. In addition, cathepsin inhibitors attenuated retinal cell toxicity induced by ethambutol. This is consistent with characteristics of lysosomal membrane permeabilization (LMP). TPEN also inhibited both lysosomal activation and LMP. Thus, accumulation of zinc in lysosomes, and eventual LMP, may be a key mechanism of ethambutol-induced retinal cell death.

Chung, Hyewon; Yoon, Young Hee [Department of Ophthalmology, Asan Medical Center, University of Ulsan, College of Medicine, 388-1 Pungnab-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Hwang, Jung Jin [Institute for Innovative Cancer Research, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Cho, Kyung Sook [Department of Ophthalmology, Asan Medical Center, University of Ulsan, College of Medicine, 388-1 Pungnab-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Koh, Jae Young [NRL Neural Injury Research Center and the Department of Neurology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Kim, June-Gone [Department of Ophthalmology, Asan Medical Center, University of Ulsan, College of Medicine, 388-1 Pungnab-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of)], E-mail: junekim@amc.seoul.kr

2009-03-01

439

Solar Cell Efficiency Tables (Version 33)  

Microsoft Academic Search

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 2008 are reviewed. Efficiencies are updated to the new reference solar spectrum tabulated in IEC 60904-3 Ed. 2 revised in April 2008 and an updated list

Martin A. Green; Keith Emery; Yoshihiro Hishikawa; Wilhelm Warta

2009-01-01

440

Radiation degradation of solar cell arrays  

NASA Technical Reports Server (NTRS)

A method of incorporating a detailed solar cell radiation degradation model into a convenient computational scheme suitable for the solar electric propulsion system is outlined. The study shows that several existing codes may be applied in sequence to solve the problem.

Hill, C. W.

1975-01-01

441

CdS Solar Cell Development.  

National Technical Information Service (NTIS)

More than half of the initial part of this program had been concerned with the overall processing aspects of the solar cell. Equipment was designed and constructed to carry out all steps necessary to the manufacturing of thin film cadmium sulfide solar ce...

J. J. Kramer R. S. Wietubicz

1973-01-01

442

V-groove multijunction solar cells  

Microsoft Academic Search

A study of three components which can be used in a solar utilization system are described. The three components are: a photovoltaic converter, an intensity sensor, and a selective thermal absorber. The results of extensive computer simulations, theoretical analyses, and measurements are reported for these components. A new family of silicon photovoltaic devices called V-Groove Multi-Junction (VGMJ) solar cells are

T. I. Chappell

1978-01-01

443

Extended Temperature Solar Cell Technology Development.  

National Technical Information Service (NTIS)

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 ce...

G. A. Landis

2005-01-01

444

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

445

The interdigitated back contact solar cell - A silicon solar cell for use in concentrated sunlight  

Microsoft Academic Search

The theoretical and experimental performance of an interdigitated back contact solar cell is described. This type of cell is shown to have significant advantages over a conventional solar cell design when used at high concentration levels, namely, reduced internal series resistance, nonsaturating open-circuit voltage, and an absence of shadowing by front surface contacting fingers. The results of a computer study

M. D. Lammert; R. J. Schwartz