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1

High-performance hydrogenated amorphous silicon-germanium solar cells fabricated by photochemical vapor deposition  

Microsoft Academic Search

High-quality a-SiGe:H films have been prepared by photochemical vapor deposition (photo-CVD) with a high dilution ratio of H2. Films with a bandgap of 1.55 eV has a photoconductivity of 0.00016 S\\/cm (AM1, 100 mW\\/sq cm). Solar cells of the p-i-n type were fabricated by applying such high-quality a-SiGe:H films to the i-layer. The performance of a-SiGe:H solar cells has been

Satoshi Yamanaka; Shinichiro Yoshida; Makoto Konagai; Kiyoshi Takahashi

1987-01-01

2

Photochemical Deposition of Semiconductor Thin Films and Their Application for Solar Cells and Gas Sensors  

SciTech Connect

The photochemical deposition (PCD) technique was applied for solar cells and gas sensors. CdS and Cd{sub 1-x}Zn{sub x}S were deposited by PCD. Thiosulfate ions S{sub 2}O{sub 3}{sup 2-} act as a reductant and a sulfur source. The SnS absorption layer was deposited by three-step pulse electrochemical deposition. For the CdS/SnS structure, the best cell showed an efficiency of about 0.2%, while for the Cd{sub 1-x}Zn{sub x}S/SnS structure, an efficiency of up to 0.7% was obtained. For the gas sensor application, SnO{sub 2} was deposited by PCD from a solution containing SnSO{sub 4} and HNO{sub 3}. To enhance the sensitivity to hydrogen, Pd was doped by the photochemical doping method. The current increased by a factor of 10{sup 4} upon exposure to 5000 ppm hydrogen within 1 min at room temperature. 10{sup 3} times conductivity increase was observed even for 50 ppm hydrogen.

Ichimura, M.; Gunasekaran, M.; Sueyoshi, T. [Dept. Engineering Physics, Electronics and Mechanics, Nagoya Institute of Technology Gokiso, Showa, Nagoya 466-8555 (Japan)

2009-06-01

3

Photochemical Deposition of Semiconductor Thin Films and Their Application for Solar Cells and Gas Sensors  

NASA Astrophysics Data System (ADS)

The photochemical deposition (PCD) technique was applied for solar cells and gas sensors. CdS and Cd1-xZnxS were deposited by PCD. Thiosulfate ions S2O32- act as a reductant and a sulfur source. The SnS absorption layer was deposited by three-step pulse electrochemical deposition. For the CdS/SnS structure, the best cell showed an efficiency of about 0.2%, while for the Cd1-xZnxS/SnS structure, an efficiency of up to 0.7% was obtained. For the gas sensor application, SnO2 was deposited by PCD from a solution containing SnSO4 and HNO3. To enhance the sensitivity to hydrogen, Pd was doped by the photochemical doping method. The current increased by a factor of 104 upon exposure to 5000 ppm hydrogen within 1 min at room temperature. 103 times conductivity increase was observed even for 50 ppm hydrogen.

Ichimura, M.; Gunasekaran, M.; Sueyoshi, T.

2009-06-01

4

Methods for the photochemical utilization of solar energy  

NASA Technical Reports Server (NTRS)

The paper considers the 'ground rules' which govern the efficiency of photochemical solar energy conversion and then summarizes the most promising approaches in each of three categories: photochemically assisted thermal systems for the heating and/or cooling of structures; photogalvanic systems for the production of electrical power in applications, such as photorechargeable batteries or inexpensive 'solar cells'; and photochemical formation of fuels for combustion and for use as chemical feedstocks or foods. Three concepts for the photochemical utilization of solar energy in space are found to be particularly promising: (1) photochemical trans-cis isomerization of indigold dyes for photoassisted heating or cooling, (2) the redox stabilized photoelectrolysis cell for the production of hydrogen (and/or oxygen or other useful chemicals), and (3) the liquid-junction photovoltaic cell for the production of electrical power.

Schwerzel, R. E.

1978-01-01

5

Photochemical conversion and storage of solar energy  

SciTech Connect

There are two ways of photochemical conversion of solar energy viz. photochemistry and photoelectrochemistry. Various concepts, developments and uses related to these aspects as well as storage of solar energy have been enumerated.

Bhavani, N.K.; Vijayalakshmi, D.; Seshan, S.

1986-03-01

6

Photochemical conversion of solar energy.  

PubMed

Energy is the most important issue of the 21st century. About 85% of our energy comes from fossil fuels, a finite resource unevenly distributed beneath the Earth's surface. Reserves of fossil fuels are progressively decreasing, and their continued use produces harmful effects such as pollution that threatens human health and greenhouse gases associated with global warming. Prompt global action to solve the energy crisis is therefore needed. To pursue such an action, we are urged to save energy and to use energy in more efficient ways, but we are also forced to find alternative energy sources, the most convenient of which is solar energy for several reasons. The sun continuously provides the Earth with a huge amount of energy, fairly distributed all over the world. Its enormous potential as a clean, abundant, and economical energy source, however, cannot be exploited unless it is converted into useful forms of energy. This Review starts with a brief description of the mechanism at the basis of the natural photosynthesis and, then, reports the results obtained so far in the field of photochemical conversion of solar energy. The "grand challenge" for chemists is to find a convenient means for artificial conversion of solar energy into fuels. If chemists succeed to create an artificial photosynthetic process, "... life and civilization will continue as long as the sun shines!", as the Italian scientist Giacomo Ciamician forecast almost one hundred years ago. PMID:18605661

Balzani, Vincenzo; Credi, Alberto; Venturi, Margherita

2008-01-01

7

Morphology and photochemical stability of P3HT:PCBM active layers of organic solar cells  

NASA Astrophysics Data System (ADS)

We report on the effects of continuous UV-visible light illumination at 60 °C in the absence of oxygen on P3HT:PCBM blend films commonly used active layer of bulk heterojunction solar cells. A full description of the behavior of P3HT:PCBM blend films either unconfined or confined by an Al cathode and a PEDOT:PSS layer during annealing treatment and irradiation is provided. We also focused on the impact of the P3HT type on the photostability. It was shown that the microstructure of P3HT dramatically influenced the photodegradation process of P3HT thin films deposited on inert substrate. The rate of photodegradation process was decreased when P3HT was blended with PCBM. It was shown that the photostability of the active layer was not influenced by a PEDOT-PSS sub-layer. Solar cells were then fabricated from high-regioregular P3HT. Many large PCBM crystals were observed in P3HT:PCBM blend films and it was shown that the top surface of the active layer in contact with the Al cathode was nearly entirely composed of P3HT. Both results account for the low performances of the devices. Finally, photo-aging experiments provoked a rapid failure of the Al cathodes which was tentatively attributed to an increase of internal strain within the devices.

Dupuis, A.; Tournebize, A.; Bussière, P.-O.; Rivaton, A.; Gardette, J.-L.

2011-12-01

8

Mapping nanoscale variations in photochemical damage of polymer/fullerene solar cells with dissipation imaging.  

PubMed

We use frequency-modulated electrostatic force microscopy to track changes in cantilever quality factor (Q) as a function of photochemical damage in a model organic photovoltaic system 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

Cox, Phillip A; Waldow, Dean A; Dupper, Torin J; Jesse, Stephen; Ginger, David S

2013-11-26

9

Improving the light-harvesting of second generation solar cells with photochemical upconversion  

NASA Astrophysics Data System (ADS)

Photovoltaics (PV) offer a solution for the development of sustainable energy sources, relying on the sheer abundance of sunlight: More sunlight falls on the Earth's surface in one hour than is required by its inhabitants in a year. However, it is imperative to manage the wide distribution of photon energies available in order to generate more cost efficient PV devices because single threshold PV devices are fundamentally limited to a maximum conversion efficiency, the Shockley-Queisser (SQ) limit. Recent progress has enabled the production of c-Si cells with efficiencies as high as 25%,1 close to the limiting efficiency of ˜30%. But these cells are rather expensive, and ultimately the cost of energy is determined by the ratio of system cost and efficiency of the PV device. A strategy to radically decrease this ratio is to circumvent the SQ limit in cheaper, second generation PV devices. One promising approach is the use of hydrogenated amorphous silicon (a-Si:H), where film thicknesses on the order of several 100nm are sufficient. Unfortunately, the optical threshold of a-Si:H is rather high (1.7-1.8 eV) and the material suffers from light-induced degradation. Thinner absorber layers in a-Si:H devices are generally more stable than thicker films due to the better charge carrier extraction, but at the expense of reduced conversion efficiencies, especially in the red part of the solar spectrum (absorption losses). Hence for higher bandgap materials, which includes a-Si as well as organic and dye-sensitized cells, the major loss mechanism is the inability to harvest low energy photons.

Cheng, Yuen Yap; Fückel, Burkhard; Schulze, Tim; MacQueen, Rowan W.; Tayebjee, Murad J. Y.; Danos, Andrew; Khoury, Tony; Clady, Raphaël. G. C. R.; Ekins-Daukes, N. J.; Crossley, Maxwell J.; Stannowski, Bernd; Lips, Klaus; Schmidt, Timothy W.

2012-09-01

10

Photochemical solar cells based on dye-sensitization of nanocrystalline TiO2  

Microsoft Academic Search

A new type of photovoltaic cell is described. It is a photoelectrochemical device that is based on the dye sensitization of thin (10-30 mum) films of TiO2 nanoparticles in contact with a non-aqueous liquid electrolyte. The cell is very simple to fabricate and, in principle, its color can be tuned through the visible spectrum, ranging from being completely transparent to

A. J. Frank; B. A. Gregg; M. Grätzel; A. J. Nozik; A. Zaban; S. Ferrere; G. Schlichthörl; S. Y. Huang

1997-01-01

11

Photochemical Solar Energy Conversion. An Assessment of Scientific Accomplishments.  

National Technical Information Service (NTIS)

Research on photochemical solar energy conversion has grown exponentially. Basic sciences have benefited most from this research. The tenet of the present Feature Article is that solar energy research has appreciably contributed to the ongoing renaissance...

J. H. Fendler

1985-01-01

12

Low-temperature Deposition of Hydrogenated Microcrystalline Silicon Thin Films by Photochemical Vapor Deposition Technique and Their Application to Thin Film Solar Cells  

NASA Astrophysics Data System (ADS)

Hydrogenated microcrystalline silicon (?c-Si:H) thin films were prepared by mercury-sensitized photochemical vapor deposition (photo-CVD) technique at various deposition temperatures. Crystalline volume fraction showed a monotonic decrease with increasing temperature from 125 to 200 °C caused by the enhanced desorption of surface hydrogen atoms. Since a similar decrease has been reported at higher temperatures than 400 °C in plasma-enhanced vapor deposition technique, we conclude that photon energy from ultraviolet radiation serves to activate surface species in photo-CVD process. In spite of the low deposition temperature, the obtained films had excellent material properties. Then, thin film solar cells were fabricated on a Type-U substrate with various haze ratios provided by Asahi Glass using such films as the i-layer. A substrate with a high haze ratio of about 50% was effective in realizing a better light-trapping structure. By decreasing the deposition temperature of the i-layer to 140 °C, conversion efficiency was improved markedly due to the improved film quality brought about by the contributions of photons from ultraviolet radiation to the enhancement of the surface migration of the radicals for reducing defects in the resulting film. Consequently, a maximum solar cell efficiency of 7.4% was obtained.

Hiza, Shuichi; Yamada, Akira; Konagai, Makoto

2007-04-01

13

Photochemical solar energy conversion. An assessment of scientific accomplishments  

Microsoft Academic Search

Research on photochemical solar energy conversion has grown exponentially. Basic sciences have benefited most from this research. The tenet of this article is that solar energy research has appreciably contributed to the ongoing renaissance of colloid chemistry and to the development of ever-more-sophisticated models for light-sensitized distance-controlled electron transfers. The need for compartmentalizing components of the photosynthetic apparatus-sensitizers: electron donors,

Janos H. Fendler

1985-01-01

14

The Photochemical Conversion of Solar Energy into Electrical Energy: Eosin-D-Xylose System  

Microsoft Academic Search

A photosensitizer-Eosin and a reductant-D-Xylose were used in the photogalvanic cell for photochemical conversion of solar energy into electrical energy. The generated photopotential and photocurrent were 825.0 mV and 250.0 ?A, respectively, whereas maximum power of the cell was 206.25 ?W. The observed power at the power point was 70.85 ?W and conversion efficiency was 0.6812%. The experimentally determined fill

K. M. Gangotri; M. K. Bhimwal

2011-01-01

15

Proceedings of the solar thermal/photochemical conversion workshop  

SciTech Connect

The Solar Energy Research Institute (SERI) hosted a workshop January 10-11, 1983 to explore the possibility of combining photochemical (or photoelectrochemical) processes with thermal conversion of solar energy to produce useful work. Experts in photochemistry, photoelectrochemistry, thermochemistry, and solar thermal technology from SERI, universities, private industry, and national laboratories were invited. Because of the diversity of technical backgrounds of the attendees, overview presentations on photoelectrochemistry, solar thermal technology, and the thermodynamics of quantum and thermal conversion of solar energy were presented on the first day. The workshop participants then formed two groups for unformatted discussions. The following day each group summarized its discussions. The overview presentations, summary presentations, and conclusions and wrap-up are presented.

Johnson, D.; Karpuk, M. (comps.)

1983-12-01

16

Solar photochemical process engineering for production of fuels and chemicals  

NASA Technical Reports Server (NTRS)

The engineering costs and performance of a nominal 25,000 scmd (883,000 scfd) photochemical plant to produce dihydrogen from water were studied. Two systems were considered, one based on flat-plate collector/reactors and the other on linear parabolic troughs. Engineering subsystems were specified including the collector/reactor, support hardware, field transport piping, gas compression equipment, and balance-of-plant (BOP) items. Overall plant efficiencies of 10.3 and 11.6 percent are estimated for the flat-plate and trough systems, respectively, based on assumed solar photochemical efficiencies of 12.9 and 14.6 percent. Because of the opposing effects of concentration ratio and operating temperature on efficiency, it was concluded that reactor cooling would be necessary with the trough system. Both active and passive cooling methods were considered. Capital costs and energy costs, for both concentrating and non-concentrating systems, were determined and their sensitivity to efficiency and economic parameters were analyzed. The overall plant efficiency is the single most important factor in determining the cost of the fuel.

Biddle, J. R.; Peterson, D. B.; Fujita, T.

1985-01-01

17

Solar photochemical process engineering for production of fuels and chemicals  

NASA Technical Reports Server (NTRS)

The engineering costs and performance of a nominal 25,000 scmd (883,000 scfd) photochemical plant to produce dihydrogen from water were studied. Two systems were considered, one based on flat-plate collector/reactors and the other on linear parabolic troughs. Engineering subsystems were specified including the collector/reactor, support hardware, field transport piping, gas compression equipment, and balance-of-plant (BOP) items. Overall plant efficiencies of 10.3 and 11.6% are estimated for the flat-plate and trough systems, respectively, based on assumed solar photochemical efficiencies of 12.9 and 14.6%. Because of the opposing effects of concentration ratio and operating temperature on efficiency, it was concluded that reactor cooling would be necessary with the trough system. Both active and passive cooling methods were considered. Capital costs and energy costs, for both concentrating and non-concentrating systems, were determined and their sensitivity to efficiency and economic parameters were analyzed. The overall plant efficiency is the single most important factor in determining the cost of the fuel.

Biddle, J. R.; Peterson, D. B.; Fujita, T.

1984-01-01

18

Solar Irradiation of Bilirubin: An Experiment in Photochemical Oxidation  

ERIC Educational Resources Information Center

An experiment in photochemical oxidation, which deals with bilirubin, a well-known light-sensitive biological compound that is pedagogically ideal for photochemical experiments at tertiary institutes, is presented. The experiment would benefit students in chemistry who eventually branch out into the health sciences or biochemistry.

Pillay A. E.; Salih, F. M.

2006-01-01

19

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

20

Photochemical Effects of Sunlight  

PubMed Central

The importance of sunlight in bringing about not only photosynthesis in plants, but also other photochemical effects, is reviewed. More effort should be devoted to photochemical storage of the sun's energy without the living plant. There is no theoretical reason to believe that such reactions are impossible. Ground rules for searching for suitable solar photochemical reactions are given, and a few attempts are described, but nothing successful has yet been found. Future possibilities are suggested. Photogalvanic cells which convert sunlight into electricity deserve further research. Eugene Rabinowitch has been an active pioneer in these fields.

Daniels, Farrington

1972-01-01

21

Photochemical, electrochemical and thermochemical transformation and storage of solar energy: Thermodynamic aspects  

NASA Astrophysics Data System (ADS)

Arguments of reversible and irreversible chemical thermodynamics are explained and applied to the transfer and storage of solar energy chemical and radiation potential. The key processes are identified as water splitting, carbon dioxide reduction and nitrogen reduction. Results on photochemical storage processes are reported.

Calzaferri, G.

1985-11-01

22

The Impact of Aerosols on Solar Ultraviolet Radiation and Photochemical Smog  

Microsoft Academic Search

Photochemical smog, or ground-level ozone, has been the most recalcitrant of air pollution problems, but reductions in emissions of sulfur and hydrocarbons may yield unanticipated benefits in air quality. While sulfate and some organic aerosol particles scatter solar radiation back into space and can cool Earth`s surface, they also change the actinic flux of ultraviolet (UV) radiation. Observations and numerical

R. R. Dickerson; S. Kondragunta; G. Stenchikov; K. L. Civerolo; B. G. Doddridge; B. N. Holben

1997-01-01

23

The impact of aerosols on solar ultraviolet radiation an photochemical smog  

SciTech Connect

Photochemical smog, or ground-level ozone, has been the most recalcitrant of air pollution problems, but reductions in emissions of sulfur and hydrocarbons may yield unanticipated benefits in air quality. While sulfate and some organic aerosol particles scatter solar radiation back into space and can cool Earth`s surface, they also change the actinic flux of ultraviolet (UV) radiation. Observations and numerical models show that UV-scattering particles in the boundary layer accelerate photochemical reactions and smog production, but UV-absorbing aerosols such as mineral dust and soot inhibit smog production. Results could have major implications for the control of air pollution. 19 refs., 4 figs.

Dickerson, R.R.; Kondragunta, S.; Stenchikov, G. [Univ. of Maryland, College Park, MD (United States)] [and others] [Univ. of Maryland, College Park, MD (United States); and others

1997-10-31

24

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

25

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

26

Actinometric measurement of solar ultraviolet and development of a weighted solar UV integral. [photochemical reaction rate determination  

NASA Technical Reports Server (NTRS)

An actinometer has been developed to measure outdoor irradiance in the range 295-400 nm. Actinometric measurements of radiation are based on determination of photochemical reaction rates for reactions of known quantum efficiency. Actinometers have the advantage of providing irradiance data over surfaces of difficult accessibility; in addition, actinometrically determined irradiance data are wavelength weighted and therefore provide a useful means of assessing the degradation rates of polymers employed in solar energy systems.

Gupta, A.; Coulbert, C.

1978-01-01

27

Mars atmosphere loss and isotopic fractionation by solar-wind-induced sputtering and photochemical escape  

NASA Technical Reports Server (NTRS)

The effects of loss of Mars atmospheric constituents by solar-wind-induced sputtering and by photochemical escape during the last 3.8 b.y. were examined. Sputtering is capable of efficiently removing all species from the upper atmosphere, including the light noble gases; N also is removed by photochemical processes. Due to the diffusive separation by mass above the homopause, removal from the top of the atmosphere will fractionate the isotopes of each species, with the lighter mass being preferentially lost. For C and O, this allows us to determine the size of nonatmospheric reservoirs that mix with the atmosphere; these reserviors can be accounted for by exchange with CO2 adsorbed in the regolith and with H2O in the polar ice deposits. Both simple analytical models and time-dependent models of the loss of volatiles from and supply to the Martian atmosphere were constructed. Both Ar and Ne require continued replenishment from outgassing over geologic time.

Jakosky, B. M.; Pepin, R. O.; Johnson, R. E.; Fox, J. L.

1993-01-01

28

Mars atmospheric loss and isotopic fractionation by solar-wind-induced sputtering and photochemical escape  

NASA Technical Reports Server (NTRS)

We examine the effects of loss of Mars atmospheric constituents by solar-wind-induced sputtering and by photochemical escape during the last 3.8 b.y. Sputtering is capable of efficiently removing all species from the upper atmosphere including the light noble gases; N is removed by photochemical processes as well. Due to diffusive separation (by mass) above the homopause, removal from the top of the atmosphere will fractionate the isotopes of each species with the lighter mass being preferentially lost. For C and O, this allows us to determine the size of nonatmospheric reservoirs that mix with the atmosphere; these reservoirs can be CO2 adsorbed in the regolith or H2O in the polar ice caps. We have constructed both simple analytical models and time-dependent models of the loss from and supply of volatiles to the Martian atmosphere.

Jakosky, B. M.; Pepin, R. O.; Johnson, R. E.; Fox, J. L.

1993-01-01

29

Solar photochemical treatment of winery wastewater in a CPC reactor.  

PubMed

Degradation of simulated winery wastewater was studied in a pilot-scale compound parabolic collector (CPC) solar reactor. Total organic carbon (TOC) reduction by heterogeneous photocatalysis (TiO(2)) and homogeneous photocatalysis with photo-Fenton was observed. The influence of TiO(2) concentration (200 or 500 mg/L) and also of combining TiO(2) with H(2)O(2) or Na(2)S(2)O(8) on heterogeneous photocatalysis was evaluated. Heterogeneous photocatalysis with TiO(2), TiO(2)/H(2)O(2) and TiO(2)/S(2)O(8)(2-) is revealed to be inefficient in removing TOC, originating TOC degradation of 10%, 11% and 25%, respectively, at best. However, photo-Fenton experiments led to 46% TOC degradation in simulated wastewater prepared with diluted wine (WV) and 93% in wastewater prepared with diluted grape juice (WG), and if ethanol is previously eliminated from mixed wine and grape juice wastewater (WW) by air stripping, it removes 96% of TOC. Furthermore, toxicity decreases during the photo-Fenton reaction very significantly from 48% to 28%. At the same time, total polyphenols decrease 92%, improving wastewater biodegradability. PMID:19899762

Lucas, Marco S; Mosteo, Rosa; Maldonado, Manuel I; Malato, Sixto; Peres, José A

2009-12-01

30

Effects of temperature and intensity on thermodynamic limits for efficiencies of photochemical conversion of solar energy  

SciTech Connect

The subject of thermodynamic limits on photochemical conversion of light to work has been of considerable interest for over twenty years. Recently, Ross and Hsiao calculated quantum conversion efficiencies for solar radiation at air mass zero (AMO). Bolton later extended this treatment to AM1.2 solar flux and also considered some kinetic as well as thermodynamic limitations. These methods are applied to a variety of solar intensities and absorber temperatures. Also, improvements in efficiency which can be obtained by using systems with several absorbers of different effective band-gap wavelengths are examined. The results, which are applicable to photovoltaic as well as to photochemical and photobiological conversion devices, represent absolute (i.e., ideal) upper limits on conversion efficiencies, analogous to Carnot efficiencies of heat engines. Also, calculations for two-photon processes (i.e., two discrete absorbers) are carried out over a limited range of temperature-intensity combinations. The treatment is extended to calculate the optimum wavelengths for multiphoton cases (3 less than or equal to n less than or equal to 8) at fixed temperature and intensity. (WHK)

Bilchak, R.V.; Connolly, J.S.; Bolton, J.R.

1980-06-01

31

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

32

The use of the solar energy in photochemical and photocatalytic processes  

NASA Astrophysics Data System (ADS)

The increasing use of the Earth's natural resources has generated increasing disposal of waste products and contamination of the environment. Many of these products are organic chemicals. Characteristic examples of waste products in the atmosphere, hydrosphere and soil are insecticides, herbicides and pesticides used to protect crops, accidental leakages and spills, and the continual discharge of waste by products in effluent streams from petrochemical and essential industries. To purify these contaminated atmospheres, hydrosphere and soil a procedure and process has been developing with minimal specific consumption energy from a renewable energy source. This paper will provide a survey and analysis of the parameters, thermal efficiency and conversion energy in the use of solar energy in the photochemical and photocatalytic degradation processes of organic effluents. As a consequence of the use of solar energy in the degradation of these effluents, a conceptual solution of a technical-technological and photocatalytic process is given for effluents which are located in watercourses and soil in Yugoslavia.

Kuburovic, Natasha D.; Valent, Vladimir J.; Todorovic, Marija S.

2003-06-01

33

Mars atmospheric loss and isotopic fractionation by solar-wind-induced sputtering and photochemical escape  

NASA Technical Reports Server (NTRS)

We examine the effects of the loss of Mars atmospheric constituents by solar-wind-induced sputtering and by photochemical escape during the past 3.8 billion years. Sputtering is capable of efficiently removing species from the upper atmosphere, including the light noble gases; nitrogen and oxygen are removed by photochemical processes as well. Due to diffusive separation (by mass) above the homopause, removal from the top of the atmosphere will fractionate the isotopes of each species, with the lighter mass being preferentially lost. For carbon and oxygen, this allows us to determine the size of nonatmospheric reservoirs which mix with the atmosphere; these reservoirs can be CO2 adsorbed in the regolith and H2O in the polar ice caps. We have constructed both simple analytical models and time-dependent models of the loss of volatiles from and supply to the martian atmosphere. Both argon and neon require continued replenishment from outgassing over geologic time. For argon, sputtering loss explains the fractionation of (Ar-36)/(Ar-38) without requiring a distinct epoch of hydrodynamic escape (although fractionation of Xe isotopes still requires very early hydrodynamic loss). For neon, the current (Ne-22)/(Ne-20) ratio represents a balance between loss to space and continued resupply from the interior; the similarity of the ratio to the terrestrial value is coincidental. For nitrogen, the loss by both sputtering and photochemical escape would produce a fractionation of (N-15)/(N-14) larger than observed; an early, thicker carbon dioxide atmosphere could mitigate the nitrogen loss and produce the observed fractionation, as could continued outgassing of juvenile nitorgen. Based on the isotopic constraints, the total amount of carbon dioxide lost over geologic time is probably on the order of tens of millibars rather than a substantial fraction of a bar. The total loss from solar-wind-induced sputtering and photochemical escape, therefore, does not seem able to explain the loss of a putative thick, early atmosphere withput requiring formation of extensive surface carbonate deposits or other nonatmospheric reservoirs for CO2.

Jakosky, Bruce M.; Pepin, Robert O.; Johnson, Robert E.; Fox, J. L.

1994-01-01

34

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

35

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

36

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

37

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

38

Optical properties of tropospheric aerosols determined by lidar and spectrophotometric measurements (Photochemical Activity and Solar Ultraviolet Radiation campaign)  

Microsoft Academic Search

We present the results of the aerosol measurements carried out over the Aegean Sea during the Photochemical Activity and Solar Ultraviolet Radiation campaign held in Greece during June 1996. Simultaneous observations performed with a lidar and a double-monochromator spectrophotometer allowed us to retrieve the optical depth, the ngstr m coefficient, and the backscatter-to-extinction ratio. The Sun photometric data can be

Franco Marenco; Vincenzo Santacesaria; Alkiviadis F. Bais; Dimitris Balis; Alcide di Sarra; Alexandros Papayannis; Christos Zerefos

1997-01-01

39

Photovoltaic cells based on pulsed electrochemically deposited SnS and photochemically deposited CdS and Cd 1? x Zn x S  

Microsoft Academic Search

CdS\\/SnS and Cd1?xZnxS\\/SnS solar cells were fabricated. SnS films were deposited by the pulsed electrochemical deposition method using an aqueous solution containing SnSO4 and Na2S2O3. CdS and Cd1?xZnxS window layers were deposited by using the photochemical deposition method using an aqueous solution containing CdSO4, ZnSO4 and Na2S2O3. Both the techniques were simple, economical and advantageous for fabricating cheap solar cells.

M. Gunasekaran; M. Ichimura

2007-01-01

40

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

41

Mathematical model that describes the transition from thermal to photochemical damage in retinal pigment epithelial cell culture  

NASA Astrophysics Data System (ADS)

We propose a rate process model for describing photochemical damage to retinal cells by short wavelength laser exposures. The rate equation for photochemical damage contains a positive rate that is temperature independent, and a negative (quenching) rate that is temperature dependent. Using the traditional Arrhenius integral to describe thermal damage, we derive damage threshold doses for both thermal and photochemical mechanisms, and show that the model accounts for the sharp transition from thermal to photochemical damage thresholds that have recently been observed in an in-vitro retinal model.

Clark, Clifton D.; Denton, Michael L.; Thomas, Robert J.

2011-02-01

42

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

43

TAT-mediated photochemical internalization results in cell killing by causing the release of calcium into the cytosol of cells  

PubMed Central

Background Lysis of endocytic organelles is a necessary step in many cellular delivery methodologies. This is achieved efficiently in the photochemical internalization approach but the cell death that accompanies this process remains a problem. Methods We investigate the mechanisms of cell death that accompanies photochemical internalization of the fluorescent peptide TMR-TAT. Results TMR-TAT kills cells after endocytosis and light irradiation. The lysis of endocytic organelles by TMR-TAT causes a rapid increase in the concentration of calcium in the cytosol. TMR-TAT co-localizes with endocytic organelles containing calcium prior to irradiation and photochemical internalization leads to the release of the lumenal content of these organelles. Ruthenium red and cyclosporin A, inhibitors of calcium import in mitochondria and of the mitochondria permeability transition pore, inhibit cell death. Conclusions TMR-TAT mediated photochemical internalization leads to a disruption of calcium homeostasis. The subsequent import of calcium in mitochondria is a causative factor of the cell death that accompanies photochemical internalization. General Significance Understanding how the lysis of endocytic organelles affects cellular physiology and causes cell death is crucial to the development of optimal delivery methodologies.

Muthukrishnan, Nandhini; Johnson, Gregory A.; Lim, Jongdoo; Simanek, Eric E.; Pellois, Jean-Philippe

2012-01-01

44

Laser-assisted solar cell metallization processing  

NASA Technical Reports Server (NTRS)

Laser-assisted processing techniques utilized to produce the fine line, thin metal grid structures that are required to fabricate high efficiency solar cells are examined. Two basic techniques for metal deposition are investigated; (1) photochemical decomposition of liquid or gas phase organometallic compounds utilizing either a focused, CW ultraviolet laser (System 1) or a mask and ultraviolet flood illumination, such as that provided by a repetitively pulsed, defocused excimer laser (System 2), for pattern definition, and (2) thermal deposition of metals from organometallic solutions or vapors utilizing a focused, CW laser beam as a local heat source to draw the metallization pattern.

Dutta, S.

1984-01-01

45

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

46

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

47

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

48

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

49

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

50

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

51

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

52

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

53

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

54

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

55

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

56

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

57

Linking solar induced fluorescence and the photochemical reflectance index to carbon assimilation in a cornfield  

NASA Astrophysics Data System (ADS)

Determining the health and vigor of vegetation using high spectral resolution remote sensing techniques is a critical component in monitoring productivity from both natural and managed ecosystems and their feedbacks to climate. This presentation summarizes a field campaign conducted in a USDA-ARS experimental cornfield site located in Beltsville, MD, USA over a five-year period. The site is equipped with an instrumented tower which makes continuous eddy covariance measurements of CO2 along with incoming PAR. Hyperspectral reflectance observations were acquired over corn canopies with a USB4000 Miniature Fiber Optic Spectrometer (Ocean Optics Inc., Dunedin, Florida, USA) at multiple times a day at various stages through the growing season. On all field days, supporting plant information and leaf level data were acquired (e.g., CO2 gas exchange) as well as biophysical field data, including leaf area index (LAI), mid-day canopy PAR transmission, soil reflectivity, and soil moisture. The canopy optical measurements enabled retrievals of the photochemical reflectance index (PRI) and solar induced fluorescence (SIF) centered at O2-A and -B bands. These two spectrally based bio-indicators have been widely utilized in studies to assess whether vegetation is performing near-optimally or exhibiting symptoms of environmental stress (e.g., drought or nutrient deficiency, non-optimal temperatures, etc.). Both SIF and PRI expressed diurnal dynamics and seasonal changes that followed environmental conditions and physiological status of the cornfield. We further investigated the correlation between these two retrievals and the flux tower based carbon assimilation observations (i.e. gross ecosystem production, GEP). We were able to successfully model the variation of GEP (r2=0.81; RMSE=0.18 mg CO2/m2/s) by utilizing both SIF and PRI. Several cross-validation algorithms were applied to the model to demonstrate the robustness and consistency of the model. Our results suggest great potential of using SIF and PRI to monitor photosynthetic activities. Further studies are needed at various ecosystems.

Cheng, Y.; Middleton, E.; Zhang, Q.; Corp, L.; Campbell, P. K.; Huemmrich, K. F.; Kustas, W.; Daughtry, C. S.; Dulaney, W. P.; Russ, A.

2012-12-01

58

Photochemical deposition of cobalt-based oxygen evolving catalyst on a semiconductor photoanode for solar oxygen production  

PubMed Central

This study describes the photochemical deposition of Co-based oxygen evolution catalysts on a semiconductor photoanode for use in solar oxygen evolution. In the photodeposition process, electron-hole pairs are generated in a semiconductor upon illumination and the photogenerated holes are used to oxidize Co2+ ions to Co3+ ions, resulting in the precipitation of Co3+-based catalysts on the semiconductor surface. Both photodeposition of the catalyst and solar O2 evolution are photo-oxidation reactions using the photogenerated holes. Therefore, photodeposition provides an efficient way to couple oxygen evolution catalysts with photoanodes by naturally placing catalysts at the locations where the holes are most readily available for solar O2 evolution. In this study Co-based catalysts were photochemically deposited as 10–30 nm nanoparticles on the ZnO surface. The comparison of the photocurrent-voltage characteristics of the ZnO electrodes with and without the presence of the Co-based catalyst demonstrated that the catalyst generally enhanced the anodic photocurrent of the ZnO electrode with its effect more pronounced when the band bending is less significant. The presence of Co-based catalyst on the ZnO photoanode also shifted the onset potential of the photocurrent by 0.23 V to the negative direction, closer to the flat band potential. These results demonstrated that the cobalt-based catalyst can efficiently use the photogenerated holes in ZnO to enhance solar O2 evolution. The photodeposition method described in this study can be used as a general route to deposit the Co-based catalysts on any semiconductor electrode with a valence band edge located at a more positive potential than the oxidation potential of Co2+ ions.

Steinmiller, Ellen M. P.; Choi, Kyoung-Shin

2009-01-01

59

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

60

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'

61

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

62

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

63

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

64

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

65

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

66

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

67

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

68

Photochemical Ozone Overburden Correction. Abstract Only.  

National Technical Information Service (NTIS)

One-half of the total ozone column is predominantly under photochemical control under all conditions except polar winter. The other half is dynamically controlled. Since the photochemical forcing is phased with the solar declination and modulated by air t...

M. Stefanick A. J. Krueger

1987-01-01

69

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

70

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

71

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

72

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.

73

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

74

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

75

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

76

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

77

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

78

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

79

Role of Superoxide Dismutase in the Photochemical Response of Cultured RPE Cells to Laser Exposure at 413 nm.  

National Technical Information Service (NTIS)

Thresholds for photochemical damage were performed in RPE cell lines (artificially pigmented) taken from either human (hTERT-RPE1), wild type (wt) mouse, or transgenic mice deficient (+/-) in either superoxide dismutase 1 (SOD1) or SOD2. The four cell lin...

K. J. Schuster L. E. Estlack M. L. Denton M. S. Foltz R. J. Thomas

2007-01-01

80

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

81

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

82

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

83

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

84

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

85

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

86

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

87

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

88

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

89

Photochemically crosslinked matrices of gelatin and fibrinogen promote rapid cell proliferation.  

PubMed

Here we report the use of a facile photochemical crosslinking method to fabricate stable polymer matrices from unmodified gelatin and fibrinogen. Gels were produced by covalent crosslinking of the proteins in a rapid photo-oxidative process, catalysed by a ruthenium metal complex and irradiation with visible light. For generation of macroporous, spongy matrices, the proteins and crosslinking reagents were mixed with catalase and hydrogen peroxide to achieve a foaming reaction, producing a stable, foamed matrix that was subsequently photo-crosslinked. C2C12 cells were either seeded onto the matrices after photo-curing or embedded in the protein matrix prior to foaming and crosslinking. Cells seeded onto scaffolds post-curing showed high cell viability and rapid proliferation in vitro. For cells embedded in the matrix prior to crosslinking there was some loss of initial viability, but surviving cells were able to proliferate after a period of in vitro cultivation. The matrices were shown to be biocompatible when implanted into nude mice, with evidence of proliferation and differentiation of cells seeded into the scaffolds. The results are promising for further development of tissue-engineering scaffolds based on this ruthenium-catalysed photo-crosslinking method. PMID:20721871

Sando, Lillian; Danon, Stephen; Brownlee, Alan G; McCulloch, Russell J; Ramshaw, John A M; Elvin, Christopher M; Werkmeister, Jerome A

2011-05-01

90

Photochemical internalization-mediated delivery of chemotherapeutic agents in human breast tumor cell lines.  

PubMed

Breast-conservation surgery (BCS) is now utilized in patients with stage I and II invasive breast cancer. However, positive surgical margins are associated with recurrence, and therefore some form of localized postoperative therapy (radiation/chemotherapy) is necessary to eliminate remaining cancer cells. Existing modalities have significant treatment-limiting side effects; therefore, alternative forms of localized therapy need to be explored. We studied the ex vivo effects of photochemical internalization (PCI) using 4 chemotherapeutic agents: cisplatin, cisplatin analog [D prostanoid, DP], doxorubicin, and bleomycin) on 3 breast cancer cell lines: MCF-7, MDA-MB-435, and MDA-MB-231. Illumination was carried out using a 670-nm diode laser at 5 mW/cm2 following incubation in the photosensitizer with aluminum phthalocyanine disulfonate. Toxicity was investigated using colony-forming assays and the mechanism of cell death was determined using Annexin flow-cytometry. We found that toxicity of DP and bleomycin was significantly enhanced by PCI compared with drug alone but was unchanged for cisplatin and doxorubicin. PCI treatment caused a decrease in the percentage of viable cells, predominantly by enhancing apoptosis. The action was synergistic across all 3 cell lines tested for DP and bleomycin. Thus, with appropriate delivery devices and choice of chemotherapeutic agents, PCI holds the promise of enhancing tumor cell toxicity surrounding the cavity of BCS resection sites and thereby decreasing local recurrence. PMID:22591284

Mathews, Marlon S; Vo, Van; Shih, En-Chung; Zamora, Genesis; Sun, Chung-Ho; Madsen, Steen J; Hirschberg, Henry

2012-01-01

91

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

92

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

93

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

94

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

95

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

96

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

97

Solar fuels  

NASA Astrophysics Data System (ADS)

The aim of this paper is to give a review concerning the storage of solar energy by converting it to chemical energy. This is based on several articles published during the last fifteen years. The methods to convert solar energy to chemical energy, e.g., to produce hydrogen, can be divided into three different methods. The most common one is probably the usage of solar cells; thus the solar energy is first converted into electrical energy and further the water is split electrochemically to produce hydrogen. It could be also done in a photoelectrochemical cell, or simply photochemically. A photobiological system can also be considered as a photochemical system, although it is discussed separately from the photochemical systems. These three last mentioned methods will be discussed in this paper.

Viitanen, M.

1990-12-01

98

The solar flare of 18 August 1979: Incoherent scatter radar data and photochemical model comparisons  

SciTech Connect

Measurements of electron density at seven D-region altidues were made with the Arecibo radar during a Class-X solar flare on 18 August 1979. Measurements of solar x-ray fluxes during the same period were available from the GOES-2 satellite (0.5 to 4 /angstrom/ and 1 to 8 /angstrom/) and from ISEE-3 (in four bands between 26 and 400 keV). From the x-ray flux data we computed ionization rates in the D-region and the associated chemical changes, using a coupled atmospheric chemistry and diffusion model (with 836 chemical reactions and 19 vertical levels). The computed electron densities matched the data fairly well after we had adjusted the rate coefficients of two reactions. We discuss the hierarchies among the many flare-induced chemical reactions in two altitude ranges within the D-region and the effects of adjusting several other rate coefficients. 51 refs., 6 figs., 3 tabs.

Zinn, J.; Sutherland, C.D.; Fenimore, E.E.; Ganguly, S.

1988-04-01

99

Photochemical solar energy conversion utilizing semiconductors localized in membrane-mimetic systems  

SciTech Connect

Extending the frontiers of colloidal photochemistry and colloidal electrochemistry to solar photochemistry research had been the main objective of this research. More specific objectives of this proposal include the examination of semiconductor-particle-mediated photoelectron transfer and photoelectric effects in different membrane mimetic systems. Emphasis had been placed on developing bilayer lipid membranes and Langmuir-Blodgett films as new membrane-mimetic systems, as well as on the characterization and utilization of these systems.

Fendler, J.H.

1991-08-31

100

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

101

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

102

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

103

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

104

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

105

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

106

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

107

Photochemical internalization enhances the efficacy of bleomycin in malignant glioma cells  

NASA Astrophysics Data System (ADS)

The utility of photochemical internalization (PCI) for the treatment of malignant gliomas was investigated in vitro using: (1) monolayers consisting of F98 rat glioma cells, and (2) human glioma spheroids established from biopsy-derived glioma cells. In both cases, the cytotoxicity of AlPcS2a- based PCI of bleomycin was compared to: (1) AlPcS2a-PDT, and (2) bleomycin. In all cases, monolayers and spheroids were incubated in AlPcS2a (18 h), bleomycin (4 h), or AlPcS2a (18 h) + bleomycin (4 h) and were subsequently exposed to 670 nm light. Toxicity was evaluated using colony formation assays or spheroid growth kinetics. Neither F98 rat glioma cells in monolayer nor human glioma spheroids were found to be particularly sensitive to the effects of low irradiance (5 mW cm-2), low radiant exposure (1.5 J cm-2) AlPcS2a -PDT. Bleomycin was found to be moderately toxic to F98 cells in monolayer at relatively low concentrations - incubation of F98 cells in 0.1 ?g ml-1 for 4 hours resulted in 80% survival. Under similar incubation conditions, the effects of bleomycin on human glioma spheroids were negligible. In both in vitro systems investigated, the PCI effect was found to be significant. For example, PCI consisting of a radiant exposure of 1.5 J cm-2 together with 0.25 ?g ml-1 bleomycin resulted in approximately 20 and 65 % survival of F98 rat glioma cells and human glioma spheroids respectively. These results show that AlPcS2a-mediated PCI can be used to enhance the efficacy of chemotherapeutic agents such as bleomycin in malignant gliomas.

Madsen, Steen J.; Blickenstaff, Joseph W.; Vo, Van; Angell-Petersen, Even; Hirschberg, Henry

2009-02-01

108

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

109

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

110

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

111

Role of superoxide dismutase in the photochemical response of cultured RPE cells to laser exposure at 413 nm  

NASA Astrophysics Data System (ADS)

Thresholds for photochemical damage were performed in RPE cell lines (artificially pigmented) taken from either human (hTERT-RPE1), wild type (wt) mouse, or transgenic mice deficient (+/-) in either superoxide dismutase 1 (SOD1) or SOD2. The four cell lines were characterized by immunohistochemical and immunoblot analyses to determine relative abundance of the SOD proteins. There was no difference in sensitivity between the human, murine wt and murine SOD1-deficient cells, whereas there was a dramatic (2 fold) increase in threshold irradiance value for the murine SOD2-deficient cells. Possible explanations for the unexpected result are provided.

Denton, Michael L.; Foltz, Michael S.; Schuster, Kurt J.; Estlack, Larry E.; Thomas, Robert J.

2008-03-01

112

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

113

Natural Variants of Photosystem II Subunit D1 Tune Photochemical Fitness to Solar Intensity*  

PubMed Central

Photosystem II (PSII) is composed of six core polypeptides that make up the minimal unit capable of performing the primary photochemistry of light-driven charge separation and water oxidation in all oxygenic phototrophs. The D1 subunit of this complex contains most of the ligating amino acid residues for the Mn4CaO5 core of the water-oxidizing complex (WOC). Most cyanobacteria have 3–5 copies of the psbA gene coding for at least two isoforms of D1, whereas algae and plants have only one isoform. Synechococcus elongatus PCC 7942 contains two D1 isoforms; D1:1 is expressed under low light conditions, and D1:2 is up-regulated in high light or stress conditions. Using a heterologous psbA expression system in the green alga Chlamydomonas reinhardtii, we have measured growth rate, WOC cycle efficiency, and O2 yield as a function of D1:1, D1:2, or the native algal D1 isoform. D1:1-PSII cells outcompete D1:2-PSII cells and accumulate more biomass in light-limiting conditions. However, D1:2-PSII cells easily outcompete D1:1-PSII cells at high light intensities. The native C. reinhardtii-PSII WOC cycles less efficiently at all light intensities and produces less O2 than either cyanobacterial D1 isoform. D1:2-PSII makes more O2 per saturating flash than D1:1-PSII, but it exhibits lower WOC cycling efficiency at low light intensities due to a 40% faster charge recombination rate in the S3 state. These functional advantages of D1:1-PSII and D1:2-PSII at low and high light regimes, respectively, can be explained by differences in predicted redox potentials of PSII electron acceptors that control kinetic performance.

Vinyard, David J.; Gimpel, Javier; Ananyev, Gennady M.; Cornejo, Mario A.; Golden, Susan S.; Mayfield, Stephen P.; Dismukes, G. Charles

2013-01-01

114

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

115

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

116

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

117

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

118

Stable, high-efficiency amorphous silicon solar cells with low hydrogen content  

SciTech Connect

Results and conclusions obtained during a research program of the investigation of amorphous silicon and amorphous silicon based alloy materials and solar cells fabricated by photo-chemical vapor and glow discharge depositions are reported. Investigation of the effects of the hydrogen content in a-si:H i-layers in amorphous silicon solar cells show that cells with lowered hydrogen content i-layers are more stable. A classical thermodynamic formulation of the Staebler-Wronski effect has been developed for standard solar cell operating temperatures and illuminations. Methods have been developed to extract a lumped equivalent circuit from the current voltage characteristic of a single junction solar cell in order to predict its behavior in a multijunction device.

Fortmann, C.M.; Hegedus, S.S. (Institute of Energy Conversion, Newark, DE (United States))

1992-12-01

119

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

120

Activation and Deactivation of DNAzyme and Antisense Function with Light for the Photochemical Regulation of Gene Expression in Mammalian Cells  

PubMed Central

The photochemical regulation of biological systems represents a very precise means of achieving high-resolution control over gene expression in both a spatial and a temporal fashion. DNAzymes are enzymatically active deoxyoligonucleotides that enable the site-specific cleavage of RNA, and have been used in a variety of in vitro applications. We have previously reported the photochemical activation of DNAzymes and antisense agents through the preparation of a caged DNA phosphoramidite and its site-specific incorporation into oligonucleotides. The presence of the caging group disrupts either DNA:RNA hybridization or catalytic activity, until removed via a brief irradiation with UV light. Here, we are expanding this concept by investigating the photochemical deactivation of DNAzymes and antisense agents. Moreover, we report the application of light-activated and light-deactivated antisense agents to the regulation of gene function in mammalian cells. This represents the first example of gene silencing antisense agents that can be turned on and turned off in mammalian tissue culture.

Young, Douglas D.; Lively, Mark O.; Deiters, Alexander

2010-01-01

121

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

122

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

123

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.

124

Simultaneous Light-Directed Synthesis of Mirror-Image Microarrays in a Photochemical Reaction Cell with Flare Suppression  

PubMed Central

The use of photolabile protecting groups is a versatile and well-established means of synthesizing high complexity microarrays of biopolymers, such as nucleic acids and peptides, for high-throughput analysis. The synthesis takes place in a photochemical reaction cell which positions the microarray substrate at the focus of the optical system delivering the light and which can be connected to a fluidics system which delivers appropriate reagents to the surface in synchrony with the light exposure. Here we describe a novel photochemical reaction cell which allows for the simultaneous synthesis of microarrays on two substrates. The reaction cell positions both substrates within the limited depth-of-focus of the optical system while maintaining the necessary reagent flow conditions. The resulting microarrays are mirror images of each other but otherwise essentially identical. The new reaction cell doubles the throughput of microarray synthesis without increasing the consumption of reagents. In addition, a secondary flow chamber behind the reaction cell can be filled with an absorbent and index-matching fluid to eliminate reflections from light exiting the reaction cell assembly, greatly reducing unintended light exposure that reduces the sequence fidelity of the microarray probes.

2013-01-01

125

PHOTOCHEMICAL BOX MODEL (PBM)  

EPA Science Inventory

This magnetic tape contains the FORTRAN source code, sample input data, and sample output data for the Photochemical Box Model (PBM). The PBM is a simple stationary single-cell model with a variable height lid designed to provide volume-integrated hour averages of O3 and other ph...

126

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

127

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

128

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

129

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

130

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

131

A flight experiment to determine GPS photochemical contamination accumulation rates  

NASA Technical Reports Server (NTRS)

It was recently suggested that photochemically deposited contamination, originating from volatiles outgassed by a spacecraft, may be responsible for the anomalous degradation in power seen on the GPS Block 1 vehicles. In an attempt to confirm, or deny, the photochemical deposition rates predicted, a study was undertaken to design a flight experiment to be incorporated on the GPS vehicles currently in production. The objective was to develop an inexpensive, light weight instrument package that would give information on the contamination levels within a few months of launch. Three types of apparatus were studied, Quartz Crystal Microbalances, (QCM's), modified solar cells, and calorimeters. A calorimeter was selected due primarily to its impact on the production schedule of the GPS vehicles. An analysis of the sensitivity of the final design is compared to the predicted contamination accumulation rates in order to determine how long after launch it will take the experiment to show the effects of photochemical contamination.

Tribble, A. C.; Haffner, J. W.

1990-01-01

132

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

133

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

134

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

135

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

136

Photochemical bonding of epithelial cell-seeded collagen lattice to rat muscle layer for esophageal tissue engineering: a pilot study  

NASA Astrophysics Data System (ADS)

Bilayered tube structures consist of epithelial cell-seeded collagen lattice and muscle layer have been fabricated for esophageal tissue engineering. Good adhesion between layers in order to facilitate cell infiltration and neovascularization in the collagen lattice is required. Previous efforts include using other bioglues such as fibrin glue and silicone tube as the physical support. However, the former is subjected to chances of transmitting blood-born infectious disease and is time consuming while the latter requires a second surgical procedure. The current project aimed to bond the cell-seeded collagen lattice to muscle layer using photochemical bonding, which has previously been demonstrated a rapid and non-thermal procedure in bonding collagenous tissues. Rat esophageal epithelial cells were seeded on collagen lattice and together with the latissimus dorsi muscle layer, were exposed to a photosensitizer rose Bengal at the bonding surface. An argon laser was used to irradiate the approximated layers. Bonding strength was measured during the peeling test of the collagen layer from the muscle layer. Post-bonding cell viability was assessed using a modified NADH-diaphorase microassay. A pilot in vivo study was conducted by directly bonding the cell-seeded collagen layer onto the muscle flap in rats and the structures were characterized histologically. Photochemical bonding was found to significantly increase the adherence at the bonding interface without compromising the cell viability. This indicates the feasibility of using the technique to fabricate multi-layered structures in the presence of living cells. The pilot animal study demonstrated integration of the collagen lattice with the muscle layer at the bonding interface although the subsequent surgical manipulation disturbed the integration at some region. This means that an additional procedure removing the tube could be avoided if the approximation and thus the bonding are optimized. Cell infiltration and neovascularization were also evident demonstrating that direct bonding of engineered tissue structures in particular those with low processability such as collagen lattice to the host tissue is feasible.

Chan, Barbara P.; Sato, M.; Vacanti, Joseph P.; Kochevar, Irene E.; Redmond, Robert W.

2005-04-01

137

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

138

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

139

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

140

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

141

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

142

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

143

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

144

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

145

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

146

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

147

In situ laser-induced photochemical silver substrate synthesis and sequential SERS detection in a flow cell.  

PubMed

A new, simple, and effective approach for multianalyte sequential surface-enhanced Raman scattering (SERS) detection in a flow cell is reported. The silver substrate was prepared in situ by laser-induced photochemical synthesis. By focusing the laser on the 320 ?m inner diameter glass capillary at 0.5 ml/min continuous flow of 1 mM silver nitrate and 10 mM sodium citrate mixture, a SERS active silver spot on the inner wall of the glass capillary was prepared in a few seconds. The test analytes, dacarbazine, 4-(2-pyridylazo)resorcinol (PAR) complex with Cu(II), and amoxicillin, were sequentially injected into the flow cell. Each analyte was adsorbed to the silver surface, enabling the recording of high intensity SERS spectra even at 2 s integration times, followed by desorption from the silver surface and being washed away from the capillary. Before and after each analyte passed the detection window, citrate background spectra were recorded, and thus, no "memory effects" perturbed the SERS detection. A good reproducibility of the SERS spectra obtained under flow conditions was observed. The laser-induced photochemically synthesized silver substrate enables high Raman enhancement, is characterized by fast preparation with a high success rate, and represents a valuable alternative for silver colloids as SERS substrate in flow approaches. PMID:21359570

Herman, Krisztian; Szabó, László; Leopold, Loredana F; Chi?, Vasile; Leopold, Nicolae

2011-05-01

148

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

149

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

150

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

151

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

152

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

153

Photochemical degradation of chromophoric-dissolved organic matter exposed to simulated UV-B and natural solar radiation  

Microsoft Academic Search

Photochemical degradation of chromophoric-dissolved organic matter (CDOM) by UV-B radiation decreases CDOM absorption in the\\u000a UV region and fluorescence intensity, and alters CDOM composition. CDOM absorption, fluorescence, and the spectral slope indicating\\u000a the CDOM composition were studied using 0.22-?m-filtered samples of Meiliang Bay water from Lake Taihu that were exposed to\\u000a short-term (0–12 h) simulated UV-B radiation and long-term (0–12 days)

Yunlin Zhang; Mingliang Liu; Boqiang Qin; Sheng Feng

2009-01-01

154

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

155

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

156

Changes in photochemically significant solar UV spectral irradiance as estimated by the composite Mg II index and scale factors  

NASA Technical Reports Server (NTRS)

Quantitative assessment of the impact of solar ultraviolet irradiance variations on stratospheric ozone abundances currently requires the use of proxy indicators. The Mg II core-to-wing index has been developed as an indicator of solar UV activity between 175-400 nm that is independent of most instrument artifacts, and measures solar variability on both rotational and solar cycle time scales. Linear regression fits have been used to merge the individual Mg II index data sets from the Nimbus-7, NOAA-9, and NOAA-11 instruments onto a single reference scale. The change in 27-dayrunning average of the composite Mg II index from solar maximum to solar minimum is approximately 8 percent for solar cycle 21, and approximately 9 percent for solar cycle 22 through January 1992. Scaling factors based on the short-term variations in the Mg II index and solar irradiance data sets have been developed to estimate solar variability at mid-UV and near-UV wavelengths. Near 205 nm, where solar irradiance variations are important for stratospheric photo-chemistry and dynamics, the estimated change in irradiance during solar cycle 22 is approximately 10 percent using the composite Mg II index and scale factors.

Deland, Matthew T.; Cebula, Richard P.

1994-01-01

157

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

158

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

159

Photochemical reaction fields with strong coupling between a photon and a molecule  

Microsoft Academic Search

To achieve a future low-carbon society, the effective utilization of photons is essential for the development of technologies based on photochemistry, such as photocatalysis and dye-sensitized solar cells, which have the potential to produce clean energy as well as preserve the environment. Here, we propose that gold nanostructures exhibiting localized surface plasmon (LSP) resonance are promising sites for photochemical reaction

Kosei Ueno; Hiroaki Misawa

2011-01-01

160

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

161

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

162

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

163

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

164

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

165

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

166

The Case for the Large Scale Development of Solar Energy  

ERIC Educational Resources Information Center

Traces the history of solar energy development. Discusses global effects (temperature, particle and other pollution) of burning fossil fuels. Provides energy balance equations for solar energy distribution and discusses flat plate collectors, solar cells, photochemical and photobiological conversion of solar energy, heat pumps. (CS)

O'Reilly, S. A.

1977-01-01

167

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

168

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...

169

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

170

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

171

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

172

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

173

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

174

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

175

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

176

Lifetime analysis and degradation study of polymer solar cells  

NASA Astrophysics Data System (ADS)

Though being much less efficient than silicon cells, organic solar cells exhibit a unique combination of interesting properties: low cost, flexibility, and the possibility of large surface coverage. Large progresses have been made over the last years using MDMO-PPV (Poly[2-methoxy-5-(3",7"-dimethyloctyloxy)-1,4-phenylenevinylene) reaching efficiencies of 2.9% and recently efficiencies over 3%, using poly(3-hexyl thiophene). A great deal of research however has still to be invested to improve the current state of the art. Among the main key-points to be addressed are namely the stability and lifetime of such devices. We are currently working on bulk heterojunction solar cells made from MDMO-PPV and PCBM (methano-fullerene[6,6]-phenyl C61-butyric acid methyl ester). Different batches of MDMO-PPV, originating from different synthesis modes (classical "Gilch" synthesis and "Sulphinyl" synthesis led by IMEC-IMOMEC) have been tested. Evolution of the power efficiency following continuous illumination (AM1.5, 80 mW.cm-2) was characterized under controlled atmosphere of nitrogen. In parallel, photodegradation studies are also investigated and electrical modeling is under way in order to get a better understanding of the relations between photochemical and electrical parameters of the diode that can be deduced from I/V curves.

de Bettignies, Remi; Leroy, Jocelyne; Chambon, Sylvain; Firon, Muriel; Sentein, Carole; Sicot, Lionel; Lutsen, Laurence J.

2004-09-01

177

Lifetime analysis and degradation study of polymer solar cells  

NASA Astrophysics Data System (ADS)

Though being much less efficient than silicon cells, organic solar cells exhibit a unique combination of interesting properties: low cost, flexibility, and the possibility of large surface coverage. Large progresses have been made over the last years using MDMO-PPV (Poly[2-methoxy-5-(3",7"-dimethyloctyloxy)-1,4-phenylenevinylene) reaching efficiencies of 2.9% and recently efficiencies over 3%, using poly(3-hexyl thiophene). A great deal of research however has still to be invested to improve the current state of the art. Among the main key-points to be addressed are namely the stability and lifetime of such devices. We are currently working on bulk heterojunction solar cells made from MDMO-PPV and PCBM (methano-fullerene[6,6]-phenyl C61-butyric acid methyl ester). Different batches of MDMO-PPV, originating from different synthesis modes (classical "Gilch" synthesis and "Sulphinyl" synthesis led by IMEC-IMOMEC) have been tested. Evolution of the power efficiency following continuous illumination (AM1.5, 80 mW.cm-2) was characterized under controlled atmosphere of nitrogen. In parallel, photodegradation studies are also investigated and electrical modeling is under way in order to get a better understanding of the relations between photochemical and electrical parameters of the diode that can be deduced from I/V curves.

de Bettignies, Remi; Leroy, Jocelyne; Chambon, Sylvain; Firon, Muriel; Sentein, Carole; Sicot, Lionel; Lutsen, Laurence

2004-11-01

178

Singlet oxygen sensitizing materials based on porous silicone: photochemical characterization, effect of dye reloading and application to water disinfection with solar reactors.  

PubMed

Photogeneration of singlet molecular oxygen ((1)O(2)) is applied to organic synthesis (photooxidations), atmosphere/water treatment (disinfection), antibiofouling materials and in photodynamic therapy of cancer. In this paper, (1)O(2) photosensitizing materials containing the dyes tris(4,4'-diphenyl-2,2'-bipyridine)ruthenium(II) (1, RDB(2+)) or tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) (2, RDP(2+)), immobilized on porous silicone (abbreviated RDB/pSil and RDP/pSil), have been produced and tested for waterborne Enterococcus faecalis inactivation using a laboratory solar simulator and a compound parabolic collector (CPC)-based solar photoreactor. In order to investigate the feasibility of its reuse, the sunlight-exposed RDP/pSil sensitizing material (RDP/pSil-a) has been reloaded with RDP(2+) (RDP/pSil-r). Surprisingly, results for bacteria inactivation with the reloaded material have demonstrated a 4-fold higher efficiency compared to those of either RDP/pSil-a, unused RDB/pSil and the original RDP/pSil. Surface and bulk photochemical characterization of the new material (RDP/pSil-r) has shown that the bactericidal efficiency enhancement is due to aggregation of the silicone-supported photosensitizer on the surface of the polymer, as evidenced by confocal fluorescence lifetime imaging microscopy (FLIM). Photogenerated (1)O(2) lifetimes in the wet sensitizer-doped silicone have been determined to be ten times longer than in water. These facts, together with the water rheology in the solar reactor and the interfacial production of the biocidal species, account for the more effective disinfection observed with the reloaded photosensitizing material. These results extend and improve the operational lifetime of photocatalytic materials for point-of-use (1)O(2)-mediated solar water disinfection. PMID:20393668

Manjón, Francisco; Santana-Magaña, Montserrat; García-Fresnadillo, David; Orellana, Guillermo

2010-06-01

179

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

180

Low-temperature photo-activated inorganic electron transport layers for flexible inverted polymer solar cells  

NASA Astrophysics Data System (ADS)

A simple and versatile route of forming sol-gel-derived metal oxide n-type electron transport layers (ETLs) for flexible inverted polymer solar cells (PSCs) is proposed using low-temperature photochemical activation process. The photochemical activation, which is induced by deep ultraviolet irradiation on sol-gel films, allows formation of metal oxide n-type ETLs such as zinc oxide (ZnO) and indium gallium zinc oxide films at a low temperature. Compared to poly(3-hexylthiophene)/phenyl-C61-butyric acid methyl ester inverted PSCs with thermally annealed ZnO ETLs (optimized efficiency of 3.26 ± 0.03 %), the inverted PSCs with photo-activated ZnO ETLs showed an improved efficiency of 3.60 ± 0.02 %. The enhanced photovoltaic property is attributed to efficient charge collection from low overall series resistance and high surface area-to-geometric area ratio by the photo-activated ZnO ETLs.

Lee, Jung-Wook; Lee, Soo-Hyoung; Kim, Yong-Hoon; Park, Sung Kyu

2014-04-01

181

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

182

Research opportunities in photochemical sciences  

SciTech Connect

The workshop entitled {open_quotes}Research Opportunities in Photochemical Sciences{close_quotes} was initiated by the U.S. Department of Energy (DOE), Office of Energy Research (ER), Office of Basic Energy Sciences (BES), Division of Chemical Sciences. The National Renewable Energy Laboratory (NREL) in Golden, Colorado was requested by ER to host the workshop. It was held February 5-8, 1996 at the Estes Park Conference Center, Estes Park, CO, and attended by about 115 leading scientists and engineers from the U.S., Japan, and Europe; program managers for the DOE ER and Energy Efficiency and Renewable Energy (EERE) programs also attended. The purpose of the workshop was to bridge the communication gap between the practioneers and supporters of basic research in photochemical science and the practioneers and supporters of applied research and development in technologies related to photochemical science. For the purposes of the workshop the definition of the term {open_quotes}photochemical science{close_quotes} was broadened to include homogeneous photochemistry, heterogeneous photochemistry, photoelectrochemistry, photocatalysis, photobiology (for example, the light-driven processes of biological photosynthesis and proton pumping), artificial photosynthesis, solid state photochemistry, and solar photochemistry. The technologies under development through DOE support that are most closely related to photochemical science, as defined above, are the renewable energy technologies of photovoltaics, biofuels, hydrogen energy, carbon dioxide reduction and utilization, and photocatalysis for environmental cleanup of water and air. Individual papers were processed separately for the United states Department of Energy databases.

NONE

1996-07-01

183

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

184

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

185

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

186

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

187

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

188

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

189

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

190

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

191

Radiation damage in biomimetic dye molecules for solar cells  

NASA Astrophysics Data System (ADS)

A significant obstacle to organic photovoltaics is radiation damage, either directly by photochemical reactions or indirectly via hot electrons. Such effects are investigated for biomimetic dye molecules for solar cells (phthalocyanines) and for a biological analog (the charge transfer protein cytochrome c). Both feature a central transition metal atom (or H2) surrounded by nitrogen atoms. Soft x-ray absorption spectroscopy and photoelectron spectroscopy are used to identify three types of radiation-induced changes in the electronic structure of these molecules. (1) The peptide bonds along the backbone of the protein are readily broken, while the nitrogen cage remains rather stable in phthalocyanines. This finding suggests minimizing peptide attachments to biologically inspired molecules for photovoltaic applications. (2) The metal atom in the protein changes its 3d electron configuration under irradiation. (3) The Fermi level EF shifts relative to the band gap in phthalocyanine films due to radiation-induced gap states. This effect has little influence on the optical absorption, but it changes the lineup between the energy levels of the absorbing dye and the acceptor/donor electrodes that collect the charge carriers in a solar cell.

Cook, Peter L.; Johnson, Phillip S.; Liu, Xiaosong; Chin, An-Li; Himpsel, F. J.

2009-12-01

192

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

193

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

194

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

195

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

196

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

197

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

198

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

199

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

200

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

201

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

202

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

203

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

204

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

205

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

206

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

207

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

208

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

209

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

210

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

211

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

212

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

213

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

214

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

215

Catalysis of Photochemical Reactions.  

ERIC Educational Resources Information Center

Offers a classification system of catalytic effects in photochemical reactions, contrasting characteristic properties of photochemical and thermal reactions. Discusses catalysis and sensitization, examples of catalyzed reactions of excepted states, complexing ground state substrates, and catalysis of primary photoproducts. (JM)

Albini, A.

1986-01-01

216

Photochemical solar energy conversion utilizing semiconductors localized in membrane-mimetic systems. Performance report, April 1, 1989--August 31, 1991  

SciTech Connect

Extending the frontiers of colloidal photochemistry and colloidal electrochemistry to solar photochemistry research had been the main objective of this research. More specific objectives of this proposal include the examination of semiconductor-particle-mediated photoelectron transfer and photoelectric effects in different membrane mimetic systems. Emphasis had been placed on developing bilayer lipid membranes and Langmuir-Blodgett films as new membrane-mimetic systems, as well as on the characterization and utilization of these systems.

Fendler, J.H.

1991-08-31

217

Photoinduced electron transfer and its applications—Study on photochemical solar energy storage and polymeric photorefractive materials  

Microsoft Academic Search

The applications of photoinduced electron transfer, one in solar energy storage and the other in polymeric photorefractive\\u000a materials are reported. In the former case, two new kinds of polymers containing norbornadiene and carbazole pendants were\\u000a synthesized. The photoisomerization of norbornadiene pendants were achieved by irradiation with the light above the wavelength\\u000a of 350 nm and a photoinduced electron transfer mechanism

Xue-Song Wang; Bao-Wen Zhang; Guang-Qian He; Yi Cao; Hong Gao; Shuo-Xing Dou; Jia-Sen Zhang; Pei-Xian Ye

1998-01-01

218

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

219

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

220

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

221

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

222

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

223

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

224

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

225

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

226

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

227

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

228

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

229

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

230

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

231

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

232

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

233

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

234

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

235

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

236

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

237

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

238

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

239

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

240

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

241

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

242

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

243

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

244

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

245

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

1977-01-01

246

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

1977-01-01

247

Towards high performance inverted polymer solar cells  

NASA Astrophysics Data System (ADS)

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

Gong, Xiong

2013-03-01

248

Space solar cells: High efficiency and radiation damage  

Microsoft Academic Search

The progress and status of efforts to increase the end-of-life efficiency of solar cells for space use is assessed. High efficiency silicon solar cells, silicon solar cell radiation damage, GaAs solar cell performance and radiation damage and 30 percent devices are discussed.

H. W. Jr. Brandhorst; D. T. Bernatowicz

1980-01-01

249

Spectral Response Measurements for Solar Cells.  

National Technical Information Service (NTIS)

An overview of spectral response measurements, measurement systems, and potential measurement problems are described relative to the characterization of solar cells. Measurement systems are outlined for determining the spectral response, external quantum ...

J. S. Hartman M. A. Lind

1981-01-01

250

The perils of solar cell efficiency measurements  

NASA Astrophysics Data System (ADS)

Ignorance and negligence are frequently causing solar cells to be mischaracterized, and invalid efficiency results have been reported in a number of journals. This problem can be greatly alleviated by employing a few simple precautions and guidelines.

Snaith, Henry J.

2012-06-01

251

Silicon Concentrator Solar Cell Manufacturing Development.  

National Technical Information Service (NTIS)

The program to design and develop the manufacturing technology for silicon solar cells sutiable for low-cost photovoltaic concentrator systems is summarized. Detailed discussions are presented for the following tasks: concentrator design, manufacturing pr...

C. Wrigley G. Storti J. Wohlgemuth

1978-01-01

252

Solar cell array design handbook, volume 1  

NASA Technical Reports Server (NTRS)

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

Rauschenbach, H. S.

1976-01-01

253

High-efficiency silicon solar cell research  

NASA Technical Reports Server (NTRS)

Progress reports on research in high-efficiency silicon solar cells were presented by eight contractors and JPL. The presentations covered the issues of Bulk and Surface Loss, Modeling, Measurements, and Proof of Concept.

Daud, T.

1984-01-01

254

Dye-sensitized solar cells  

DOEpatents

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

Skotheim, Terje A. (Berkeley, CA)

1980-01-01

255

Dye-sensitized solar cells  

DOEpatents

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

Skotheim, T.A.

1980-03-04

256

Large area polymer solar cells  

NASA Astrophysics Data System (ADS)

The fabrication of very large area polymer based solar cell modules with a total aperture area of 1000 cm2 has been accomplished. The substrate was polyethyleneterephthalate (PET) foil with a pre-etched pattern of indium-tin-oxide (ITO) anodes. The module was constructed as a matrix of 91 devices comprising 7 rows connected in parallel with each row having 13 individual cells connected in series. The printing of the organic layer employed screen printing of a chlorobenzene solution of the active material that consisted of either poly-1,4-(2-methoxy-5-ethylhexyloxy) phenylenevinylene (MEH-PPV) on its own or a 1:1 mixture (w/w) of MEH-PPV and [6,6]-phenyl-C61-butanoic acid methyl ester (PCBM). Our first results employed e-beam evaporation of the aluminium cathode directly onto the active layer giving devices with very poor performance that was discouragingly lower than expected by about three orders of magnitude. We found that e-beam radiation leads to a much poorer performance and thermal evaporation of the aluminium using a basket heater improved these values by an order of magnitude in efficiency for the geometry ITO/MEH-PPV/C60/Al. Finally the lifetimes (?1/2) of the modules were established and were found to improve significantly when a sublimed layer of C60 was included between the polymer and the aluminium electrode. Values for the half life of 150 hours were typically obtained. This short lifetime is linked to reaction between the reactive metal electrode (aluminium) and the constituents of the active layer.

Krebs, Frederik C.; Alstrup, Jan; Biancardo, Matteo; Spanggaard, Holger

2005-10-01

257

Spectroscopic studies of second-generation sensitizers and their photochemical reactions in liposomes and cells  

NASA Astrophysics Data System (ADS)

The photosensitization mechanism and kinetics of hematoporphyrin derivative (HPD), photofrin II (PF-II) and Zn2+-phthalocyanine tetrahydroxyl (ZnPC) are compared with the newly introduced sensitizers Zn2+ and Mg2+-tetrabenzoporphyrin (ZnTBP and MgTBP), in lipid vesicles. 9,10-dimethyl anthracene was used as a fluorescent target for singlet oxygen-mediated photosensitization. From the kinetics the quantum yield of singlet oxygen generation was calculated. MgTBP is compared with hematoporphyrin for the ability to photodamage bacterial cells and human cancer cells. MgTBP was found to have a comparable capacity for such a biological effect.

Ehrenberg, Benjamin; Gross, Eitan; Lavi, Adina; Johnson, Fred M.; Malik, Zvi

1991-06-01

258

Laser-assisted solar cell metallization processing  

NASA Technical Reports Server (NTRS)

Laser assisted processing techniques utilized to produce the fine line, thin metal grid structures that are required to fabricate high efficiency solar cells are investigated. The tasks comprising these investigations are summarized. Metal deposition experiments are carried out utilizing laser assisted pyrolysis of a variety of metal bearing polymer films and metalloorganic inks spun onto silicon substrates. Laser decomposition of spun on silver neodecanoate ink yields very promising results. Solar cell comb metallization patterns are written using this technique.

Dutta, S.

1984-01-01

259

Impurity gradients and high efficiency solar cells  

NASA Technical Reports Server (NTRS)

One potential means of improving the efficiency of solar cells especially after space irradiation is to incorporate built-in fields into the device through the use of impurity doping gradients. A detailed numerical calculation of solar cell performance has been used to study various types of doping gradients. In general, the predicted improvements in performance have been less than previously reported due to various device effects such as, high injection and the dependence of lifetime on doping density.

Fang, C. R.; Hauser, J. R.

1977-01-01

260

Stretchable, wearable dye-sensitized solar cells.  

PubMed

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

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

2014-05-01

261

Dye sensitized solar cells on paper substrates  

Microsoft Academic Search

This article reports for the first time in the literature, a dye sensitized solar cells with 1.21% efficiency (Voc=0.56V, Jsc=6.70mA\\/cm2 and F.F.=0.33) on paper substrates. The current dye sensitized solar cell technology is based on fluorine doped SnO2 (FTO) coated glass substrates. The problem with the glass substrate is its rigidity and heavy weight. Making DSSCs on paper opens the

Bo Wang; Lei L. Kerr

2011-01-01

262

Nanowire dye-sensitized solar cells  

Microsoft Academic Search

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

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

2005-01-01

263

High-temperature Solar Cell Development  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

264

Thin film solar cells for indoor use  

Microsoft Academic Search

The effect of low irradiance for thin film solar cells is investigated in this work. First, a-Si:H\\/CIGS\\/DSSC\\/OPV four kinds of thin film solar cells are fabricated and measured with the sun simulator (AM 1.5G, 100 mW\\/cm2). Then, the saturation current density J0 is extracted from the Voc and Jsc. Spectral irradiance of the desk light, LED light, sun light at

P. C. Yang; I. M. Chan; C. H. Lin; Y. L. Chang

2011-01-01

265

Limiting efficiency of silicon solar cells  

Microsoft Academic Search

The detailed balance method for calculating the radiative recombination limit to the performance of solar cells has been extended to include free carrier absorption and Auger recombination in addition to radiative losses. This method has been applied to crystalline silicon solar cells where the limiting efficiency is found to be 29.8 percent under AM1.5, based on the measured optical absorption

TOM TIEDJE; ELI YABLONOVITCH; GEORGE D. CODY; BONNIE G. BROOKS

1984-01-01

266

Status of polycrystalline solar cell technologies  

Microsoft Academic Search

Thin-film cadmium telluride (CdTe) and thin-film copper indium diselenide (CIS) solar cells are discussed. The issues these technologies face before commercialization are addressed. The authors conclude that high-efficiency (15-18%) polycrystalline silicon modules will dominate the market in the near future, and impressive results for thin-film CdTe and CIS solar cells and their outdoor stability will attract increased interest in these

Vijay K. Kapur; Bulent M. Basol

1991-01-01

267

Hydrogen passivation of multicrystalline silicon solar cells  

Microsoft Academic Search

The use of hydrogen for passivation of multicrystalline silicon in solar cell technology is described. Three kinds of hydrogen incorporation into mc-Si solar cells have been evaluated: hydrogen diffusion out of a SiN-layer (SiN:H), low-energy hydrogen ion implantation (HII), and remote plasma hydrogen passivation (RPHP). Best results were obtained by RPHP, whereas using HII, damage exceeded the passivation effect to

Ralf Lüdemann

1999-01-01

268

Multijunction Solar Cells Optimized for the Mars Surface Solar Spectrum  

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

269

Very thin silicon wafer base solar cell  

Microsoft Academic Search

The performance and ruggedness of very thin silicon back surface field (Bsf) solar cells are improved by the formation of a relatively thick, epitaxially grown, highly doped layer at the back of the cell and the formation of an arsenic doped layer at the top of the cell within the phosphorous diffused front region. As a result of these modifications

Mandelkorn

1982-01-01

270

Improved protection for silicon solar cells  

NASA Technical Reports Server (NTRS)

Fluorinated ethylene propylene /FEP/ film is substituted for epoxy cement in bonding glass covers to silicon solar cells. Insensitivity of FEP to ultraviolet radiation reduces requirement for filtering and does not impair cell performance. Cell costs are reduced and cover mounting is simplified.

Broder, J. D.

1970-01-01

271

Transparent superstrate terrestrial solar cell module  

NASA Technical Reports Server (NTRS)

The design, development, fabrication, and testing of the transparent solar cell module were examined. Cell performance and material process characteristics were determined by extensive tests and design modifications were made prior to preproduction fabrication. These tests included three cell submodules and two full size engineering modules. Along with hardware and test activity, engineering documentation was prepared and submitted.

1977-01-01

272

Space solar cell technology development - a perspective  

Microsoft Academic Search

The history of space solar cell development is examined and used to forecast future progress. Major challenges facing the implementation of GaAs cell technology are discussed. Areas of silicon cell development, such as configuration changes and approaches to obtaining improved space radiation resistance, which could prove significant for future mission needs are identified. It is suggested that users of silicon

Scott-Monck

1982-01-01

273

Ideal theory of quantum well solar cells  

Microsoft Academic Search

An ideal model for quantum well solar cells is developed and is used to theoretically explore the dependence of terminal characteristics on the host cell and quantum well properties. The model, which explicitly treats carrier generation and recombination in the quantum wells, is described and compared with an analogous ideal model for bulk homojunction cells. Open-circuit voltages, short-circuit current densities,

Neal G. Andersona

1995-01-01

274

Coatings Boost Solar-Cell Outputs  

NASA Technical Reports Server (NTRS)

Efficiencies increased by more-complete utilization of incident light. Electrical outputs of thin solar photovoltaic cells made of dendritic-web silicon increased by combination of front-surface, antireflective coatings and back-surface, reflective coatings. Improvements achieved recently through theoretical and experimental studies of ways to optimize coatings for particular wavelengths of incident light, cell thicknesses, and cell materials.

Rohatgi, Ajeet; Campbell, Robert B.; O'Keefe, T. W.; Rai-Choudbury, Posenjit; Hoffman, Richard A.

1988-01-01

275

All solution processible polymer multijunction solar cells  

NASA Astrophysics Data System (ADS)

Conjugated polymer based organic solar cells are a promising alternative to conventional silicon solar cells due to low material and fabrication cost, ease of processability, and mechanical flexibility, while solar cells with a multijunction structure have high potential to achieve enhanced efficiency and cost effectiveness. The goal of this dissertation was to stack narrow band absorbers with efficient interfacial layers in multiple junctions for broad spectrum light harvesting to achieve cost effectiveness. Specific objectives were to develop cost effective interfacial layers, and to design and fabricate solution processible polymer single and multijunction solar cells to achieve 10 % efficiency. A novel recombination layer of Nb2O5-PEDOT:PSS was developed along with single and double junction solar cells using a MDMO-PPV:PC 60BM, P3HT:PC60BM and PSBTBT:PC70BM polymer blend. Simulations showed that the maximum achievable efficiency for single, double, triple, and quadruple junction polymer solar cells were 13 %, 19 %, 22 %, and 24 % respectively, indicating the potential of multijunction devices. XRD reveled that the Nb2O5 used as the recombination layer was amorphous and AFM and KFM microscopic studies showed that the charge transfer barrier from PC60BM to Nb2O5 was only ˜0.2 eV. A MDMO-PPV:PC60BM based double junction solar cell using Nb2O5 electron transport layer exhibited a Voc of 1.30 V, which was close to the sum of the Voc’s of the individual subcells. Simulation results showed that cell efficiency using Nb2O5 as an electron transport layer could be significantly increased by reducing the series resistance (Rse) and matching the current densities of the individual subcells. Nb2O5-PEDOT:PSS was used in a high band gap P3HT and low band gap polymer based double junction solar cell, and the performance obtained was very promising though the PSBTBT:PC 70BM back subcell appeared to be the performance limiting cell with low FF and high series and low shunt resistance. If all the single junction solar cells used as subcells are optimized, the double junction device based on this recombination layer will reach higher efficiency. Future work should include developing triple or quadruple junction solar cells using the Nb2O5 nanoparticles doped with other transitional metals as an interfacial layer along with novel donor and acceptor materials towards an efficiency greater than 10 %.

Siddiki, Mahbube Khoda

276

Simulations with CAO-3D model of photochemical response caused by precipitating electrons and solar protons at both polar regions during geomagnetic storms in October-November 2003 (preliminary comparison with MIPAS data)  

NASA Astrophysics Data System (ADS)

Relativistic electrons precipitating from radiation belts and solar protons can penetrate below 100 km into the polar atmosphere sometimes reaching the stratospheric levels wasting its energy and causing the ionization. It leads to additional production of NOx and HOx chemical com-pounds which destroy ozone in the chemical catalytic cycles. One of the strongest geomagnetic storms accompained by a strong Solar Proton Eevent (SPE) occured in October-November 2003. This period was covered also by observations with MIPAS instrument placed on board of ENVISAT satellite. The response of atmospheric chemical composition in both polar regions was studied with CAO-3D photochemical-transport model. In order to calculate ionization rates induced by precipitating electrons and solar protons during late October and November 2003, corresponding proton and electron fluxes in different energetic channels from GOES-10 and POES-15/16 have been used. The Atmospheric Ionization Module Osnabruck -AIMOS /Wissing and Kallenrode, 2009/ was used to calculate 3D fields of ionization rates separately by electrons and protons. Photochemical simulations showed that Northern and Southern po-lar regions had different photochemical response. Such difference mostly is the result of the two factors: polar cap expansion during the geomagnetic storm and the effect of horizontal transport. The calculated members of NOy, HOx, Cly families were preliminary compared with corresponding observed data measured by MIPAS and showed a general agreement. The sensitivity of calculated chemical response to the efficiencies of NOx and HOx production by en-ergetic particles have been studied also. This work was supported by Russian Science Foudation for Basic Research (grant 09-05-009949) and by contract 1-6-08 under Russian Sub-Program "Reseach and Investigation of Antarctica".

Krivolutsky, Alexei A.; Banin, Max; Maik Wissing, Jan; Vyushkova, Tatyana

277

Optimization and performance of Space Station Freedom solar cells  

NASA Technical Reports Server (NTRS)

High efficiency, large area and low cost solar cells are the drivers for Space Station solar array designs. The manufacturing throughput, process complexity, yield of the cells, and array manufacturing technique determine the economics of the solar array design. The cell efficiency optimization of large area (8 x 8 m), dielectric wrapthrough contact solar cells are described. The results of the optimization are reported and the solar cell performance of limited production runs is reported.

Khemthong, S.; Hansen, N.; Bower, M.

1991-01-01

278

Comparative values of advanced space solar cells  

NASA Astrophysics Data System (ADS)

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

Slifer, L. W., Jr.

1982-09-01

279

Comparative values of advanced space solar cells  

NASA Technical Reports Server (NTRS)

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

Slifer, L. W., Jr.

1982-01-01

280

Manufacture of Solar Cells on the Moon  

NASA Technical Reports Server (NTRS)

In support of the space exploration initiative a new architecture for the production of solar cells on the lunar surface is devised. The paper discusses experimental data on the fabrication and properties of lunar glass substrates, evaporated lunar regolith thin film (antireflect coatings and insulators), and preliminary attempts in the fabrication of thin film (silicon/II-VI) photovoltaic materials on lunar regolith substrates. A conceptual design for a solar powered robotic rover capable of fabricating solar cells directly on the lunar surface is provided. Technical challenges in the development of such a facility and strategies to alleviate perceived difficulties are discussed. Finally, preliminary cost benefit ratio analysis for different in situ solar cell production scenarios (using exclusively in-situ planetary resources or hybrid) are discussed.

Freundich, Alex; Ignatiev, Alex; Horton, Charles; Duke, Mike; Curren, Peter; Sibille, Laurent

2005-01-01

281

Peptide-templating dye-sensitized solar cells.  

PubMed

A hollow TiO(2) nanoribbon network electrode for dye-sensitized solar cells (DSSC) was fabricated by a biotemplating process combining peptide self-assembly and atomic layer deposition (ALD). An aromatic peptide of diphenylalanine was assembled into a three-dimensional network consisting of highly entangled nanoribbons. A thin TiO(2) layer was deposited at the surface of the peptide template via the ALD process. After the pyrolysis of the peptide template, a highly entangled nanotubular TiO(2) framework was successfully prepared. Evolution of the crystal phase and crystallite size of the TiO(2) nanostructure was exploited by controlling the calcination temperature. Finally, the hollow TiO(2) nanoribbon network electrode was integrated into DSSC devices and their photochemical performances were investigated. Hollow TiO(2) nanoribbon-based DSSCs exhibited a power conversion efficiency of 3.8%, which is comparable to the conventional TiO(2) nanoparticle-based DSSCs (3.5%). Our approach offers a novel pathway for DSSCs consisting of TiO(2) electrodes via biotemplating. PMID:20378945

Han, Tae Hee; Moon, Hyoung-Seok; Hwang, Jin Ok; Seok, Sang Il; Im, Sang Hyuk; Kim, Sang Ouk

2010-05-01

282

Stable, high-efficiency amorphous silicon solar cells with low hydrogen content. Annual subcontract report, 1 March 1991--31 January 1992  

SciTech Connect

Results and conclusions obtained during a research program of the investigation of amorphous silicon and amorphous silicon based alloy materials and solar cells fabricated by photo-chemical vapor and glow discharge depositions are reported. Investigation of the effects of the hydrogen content in a-si:H i-layers in amorphous silicon solar cells show that cells with lowered hydrogen content i-layers are more stable. A classical thermodynamic formulation of the Staebler-Wronski effect has been developed for standard solar cell operating temperatures and illuminations. Methods have been developed to extract a lumped equivalent circuit from the current voltage characteristic of a single junction solar cell in order to predict its behavior in a multijunction device.

Fortmann, C.M.; Hegedus, S.S. [Institute of Energy Conversion, Newark, DE (United States)

1992-12-01

283

Functionalized fullerenes mediate photodynamic killing of cancer cells: Type I versus Type II photochemical mechanism  

PubMed Central

Photodynamic therapy (PDT) employs the combination of non-toxic photosensitizers (PS) and harmless visible light to generate reactive oxygen species (ROS) and kill cells. Most clinically studied PS are based on the tetrapyrrole structure of porphyrins, chlorins and related molecules, but new non-tetrapyrrole PS are being sought. Fullerenes are soccer-ball shaped molecules composed of sixty or seventy carbon atoms and have attracted interest in connection with the search for biomedical applications of nanotechnology. Fullerenes are biologically inert unless derivatized with functional groups, whereupon they become soluble and can act as PS. We have compared the photodynamic activity of six functionalized fullerenes with 1, 2, or 3 hydrophilic or 1, 2, or 3 cationic groups. The octanol-water partition coefficients were determined and the relative contributions of Type I photochemistry (photogeneration of superoxide in the presence of NADH) and Type II photochemistry (photogeneration of singlet oxygen) were studied by measurement of oxygen consumption, 1270-nm luminescence and EPR spin-trapping of the superoxide product. We studied three mouse cancer cell lines: (J774, LLC and CT26) incubated for 24 h with fullerenes and illuminated with white light. The order of effectiveness as PS was inversely proportional to the degree of substitution of the fullerene nucleus for both the neutral and cationic series. The mono-pyrrolidinium fullerene was the most active PS against all cell lines and induced apoptosis 4–6 hours after illumination. It produced diffuse intracellular fluorescence when dichlorodihydrofluorescein was added as an ROS probe suggesting a Type I mechanism for phototoxicity. We conclude that certain functionalized fullerenes have potential as novel PDT agents and phototoxicity may be mediated both by superoxide and by singlet oxygen.

Mroz, Pawel; Pawlak, Anna; Satti, Minahil; Lee, Haeryeon; Wharton, Tim; Gali, Hariprasad; Sarna, Tadeusz; Hamblin, Michael R.

2007-01-01

284

Advanced solar cells for satellite power systems  

NASA Astrophysics Data System (ADS)

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

Flood, Dennis J.; Weinberg, Irving

1994-11-01

285

Advanced solar cells for satellite power systems  

NASA Technical Reports Server (NTRS)

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

Flood, Dennis J.; Weinberg, Irving

1994-01-01

286

Flexible solid-state dye solar cells  

NASA Astrophysics Data System (ADS)

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 as transparent substrate. Steel, titanium and polymer foil based cell were assembled. The polymer/ITO cell gave only small currents as the materials are far from optimal in that configuration, but an efficiency of 0.8 % was obtained on a Ti-foil based cell.

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

2002-02-01

287

Photochemical internalization (PCI) of immunotoxins targeting CD133 is specific and highly potent at femtomolar levels in cells with cancer stem cell properties.  

PubMed

CD133 is a putative cancer stem cell (CSC) marker for a number of different cancers and is suggested to be a therapeutic target. Since also normal stem cells express CD133 it is of paramount importance that targeting strategies provide a specific and efficient delivery of cytotoxic drugs in only CD133-positive CSCs. In this study, we have employed photochemical internalization (PCI), a minimally invasive method for light-controlled, specific delivery of membrane-impermeable macromolecules from endocytic vesicles to the cytosol, to specifically target CD133-positive cancer cells. We demonstrate that PCI increases the cytotoxic effect of an immunotoxin (IT) targeting CD133-expressing cancer cells of colon (WiDr and HCT116) and pancreas (BxPC-3) origin. The IT consisted of the mAb CD133/1 (AC133) bound to the ribosome inactivating plant toxin saporin (anti-CD133/1-sap). We show that TPCS2a-PCI of anti-CD133/1-sap is specific, and highly cytotoxic at femto-molar concentrations. Specific binding and uptake of CD133/1, was shown by fluorescence microscopy and co-localization with TPCS2a in endosomes/lysosomes was determined by confocal microscopy. CD133(high) WiDr cells, isolated by fluorescence activated cell sorting, had a 7-fold higher capacity to initiate spheroids than CD133(low) cells (P<0.001) and were resistant to photodynamic therapy (PDT). However, PDT-resistance was bypassed by the PCI strategy. Tumor initiation and aggressive growth in athymic nude mice was obtained with only 10 CD133(high) cells in contrast to CD133(low) cells where substantially higher cell numbers were needed. The excellent high efficacy and selectivity of eliminating CD133-expressing cells by PCI warrant further pre-clinical evaluations of this novel therapeutic approach. PMID:23567040

Bostad, Monica; Berg, Kristian; Høgset, Anders; Skarpen, Ellen; Stenmark, Harald; Selbo, Pål K

2013-06-28

288

Developing an Advanced Module for Back-Contact Solar Cells  

Microsoft Academic Search

This paper proposes a novel concept for integrating ultrathin solar cells into modules. It is conceived as a method for fabricating solar panels starting from back-contact crystalline silicon solar cells. However, compared to the current state of the art in module manufacturing for back-contact solar cells, this novel concept aims at improvements in performance, reliability, and cost through the use

Jonathan Govaerts; Jo Robbelein; Mario Gonzalez; Ivan Gordon; Kris Baert; Ingrid De Wolf; Frederick Bossuyt; Steven Van Put; Jan Vanfleteren

2011-01-01

289

Third Working Meeting on Gallium Arsenide Solar Cells  

NASA Technical Reports Server (NTRS)

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

Walker, G. H. (compiler)

1976-01-01

290

Spectral conversion for solar cell efficiency enhancement using YVO4:Bi3+,Ln3+ (Ln = Dy, Er, Ho, Eu, Sm, and Yb) phosphors  

Microsoft Academic Search

Bi3+–Ln3+ (Ln = Dy, Er, Ho, Eu, and Sm) co-doped YVO4 phosphors are proposed as UV-absorbing luminescent converter candidate to enhance the power conversion efficiency and photochemical stability of dye-sensitized solar cells (DSSCs). The phosphors can efficiently convert UV photons in a broad range from 250 to 400 nm into visible emissions, which can be absorbed by DSSCs. Efficient broadband

X. Y. Huang; J. X. Wang; D. C. Yu; S. Ye; Q. Y. Zhang; X. W. Sun

2011-01-01

291

Spectral conversion for solar cell efficiency enhancement using YVO4:Bi3+,Ln3+ (Ln = Dy, Er, Ho, Eu, Sm, and Yb) phosphors  

Microsoft Academic Search

Bi3+-Ln3+ (Ln = Dy, Er, Ho, Eu, and Sm) co-doped YVO4 phosphors are proposed as UV-absorbing luminescent converter candidate to enhance the power conversion efficiency and photochemical stability of dye-sensitized solar cells (DSSCs). The phosphors can efficiently convert UV photons in a broad range from 250 to 400 nm into visible emissions, which can be absorbed by DSSCs. Efficient broadband

X. Y. Huang; J. X. Wang; D. C. Yu; S. Ye; Q. Y. Zhang; X. W. Sun

2011-01-01

292

Solar cell radiation handbook. [Degradation of solar cells in space radiation environment  

Microsoft Academic Search

The purpose of this document is to detail a method of predicting the degradation of a solar array in a space radiation environment. The text contains a discussion of solar cell technology which emphasizes the cell parameters which degrade in a radiation environment. The experimental techniques used in the evaluation of radiation effects are discussed. The theoretical aspects of radiation

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

1977-01-01

293

Performance measurement of dye-sensitized solar cells and organic polymer solar cells  

Microsoft Academic Search

Performance characterization of the dye-sensitized solar cells (DSC) and organic polymer solar cells (OSC) has been investigated, in order to clarify how to accurately determine their performance. Accurate characterization of DSC requires consideration on the very slow temporal response, and variation of the quantum efficiency spectrum for the bias light. The I-V curves of the DSC are clearly dependent on

Yoshihiro Hishikawa

2008-01-01

294

Advanced Modelling of Silicon Wafer Solar Cells  

NASA Astrophysics Data System (ADS)

Modelling of solar cells today is general practice in research and widely-used in industry. Established modelling software is typically limited to one dimension and/or to small scales. Additionally, novel effects, like, e.g., the use of diffractive structures or luminescent materials, are not established. In this paper we discuss how the combination of different modelling techniques can be used to overcome these limitations. In this context two examples are presented. The first example concerns the combination of the open source simulation software PC1D with circuit modelling to investigate the effect of local shunts on the global characteristics of a silicon wafer solar cell. For the investigated example (4.5 cm2 cell area) we find that a local point shunt reduces the solar cell efficiency by 4% relative. The second example concerns the modelling of diffractive gratings for thin silicon wafer solar cells. For this purpose, we use the rigorous coupled wave analysis to simulate Sentaurus technical computer-aided design (TCAD) is combined with the rigorous coupled wave analysis, a method to solve Maxwell's equations for periodic structures. Here we show that a grating can be used to improve the absorption in a thin silicon wafer solar cell considerably.

Peters, Marius; Fajun, Ma; Siyu, Guo; Hoex, Bram; Blaesi, Benedikt; Glunz, Stefan; Aberle, Armin; Luther, Joachim

2012-10-01

295

Large area space solar cell assemblies  

NASA Technical Reports Server (NTRS)

Results of the development of a 34.3 sq cm space solar cell and integral glass cover are presented. Average AM(0) cell efficiency is 14 percent. The cell design includes a high performance back surface reflector yielding a thermal alpha of approximately 0.66. A novel process is described which integrates cell fabrication and encapsulation thereby achieving a reduction of encapsulation cost. Test results indicate the potential of this new technology.

Nowlan, M. J.; Spitzer, M. B.

1982-01-01

296

MIS silicon solar cells: potential advantages  

SciTech Connect

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

Cheek, G.; Mertens, R.

1981-05-01

297

Plastic Schottky-barrier solar cells  

DOEpatents

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

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

1981-12-30

298

High voltage planar multijunction solar cell  

NASA Technical Reports Server (NTRS)

A high voltage multijunction solar cell is provided wherein a plurality of discrete voltage generating regions or unit cells are formed in a single generally planar semiconductor body. The unit cells are comprised of doped regions of opposite conductivity type separated by a gap or undiffused region. Metal contacts connect adjacent cells together in series so that the output voltages of the individual cells are additive. In some embodiments, doped field regions separated by a overlie the unit cells but the cells may be formed in both faces of the wafer.

Evans, J. C., Jr.; Chai, A. T.; Goradia, C. P. (inventors)

1982-01-01

299

Silicon solar cell process. Development, fabrication and analysis  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

300

Microstructural analysis of solar cell welds  

NASA Astrophysics Data System (ADS)

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

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

301

Radiation tests of SEP solar cells  

NASA Technical Reports Server (NTRS)

Solar cells specially designed for Solar Electric Propulsion (SEP) were tested with radiation fluences up to 10 to the 12th power protons having energies of 1.5, 1.0, and 0.5 MeV, and with fluences up to 10 to the 16th power electrons having 1.0 MeV energy. Spectrolab cells having a back-surface field were also irradiated with the same particles and fluences. Cell performances are described by curves in which normalized and absolute values of maximum power, maximum-power voltage, short-circuit current, and open-circuit voltage are plotted as a function of fluence.

Oman, H.

1977-01-01

302

Microstructural analysis of solar cell welds  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

303

Terrestrial solar spectra, solar simulation, and solar-cell-efficiency measurement  

SciTech Connect

After a discussion of the fundamentals of light transmittance, both measured and modeled atmospheric effects (i.e., air mass, molecular and aerosal scattering, and absorption) on terrestrial solar spectra are discussed. Geometric effects, such as global rather than direct beam measurements, and detector orientation are also reviewed. The SERI proposed ASTM global and direct beam terrestrial solar spectra are also presented. Then a detailed review/evaluation of the spectral characteristics of a number of solar simulators is given. Methods of calibrating the short circuit current of a solar cell with respect to a given irradiance spectrum are discussed. In conclusion, the need for a sophisticated solar simulator is proportional to the spectral mismatch between the spectral response of the reference cell used to set the solar simulator and that of the test cell. The report recommends using the recently proposed ASTM terrestrial solar irradiance spectrum as a reference spectrum and using either filtered xenon-arc or dichroic filtered tungsten-halogen (ENX or ELH) lamps for solar simulation.

Matson, R.; Bird, R.; Emery, K.

1981-09-01

304

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

Microsoft Academic Search

Due to energy crises in the future, much effort is being directed towards alternate sources. Solar energy is accepted as a novel substitute for conventional sources of energy. Out of the long list of various types of solar cells available on the market, solid state photoelectrochemical solar cells (SSPECs) and dye sensitized solar cells (DSSCs) are proposed as an alternative

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

2011-01-01

305

Flexible implementation of rigid solar cell technologies  

Microsoft Academic Search

As a source of clean, remote energy, photovoltaic (PV) systems are an important area of research. The majority of solar cells are rigid materials with negligible flexibility. Flexible PV systems possess many advantages, such as being transportable and incorporable on diverse structures. Amorphous silicon and organic PV systems are flexible; however, they lack the efficiency and lifetime of rigid cells.

Hollowell; Andrew E

2010-01-01

306

Large area space solar cell assemblies  

NASA Technical Reports Server (NTRS)

Development of a large area space solar cell assembly is presented. The assembly consists of an ion implanted silicon cell and glass cover. The important attributes of fabrication are (1) use of a back surface field which is compatible with a back surface reflector, and (2) integration of coverglass application and call fabrication.

Spitzer, M. B.; Nowlan, M. J.

1982-01-01

307

Method of restoring degraded solar cells  

DOEpatents

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

Staebler, David L. (Lawrenceville, NJ)

1983-01-01

308

High-efficiency concentrator silicon solar cells  

NASA Astrophysics Data System (ADS)

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 demonstrated 21 to 22 percent for one-sun cells in sizes up to 37.5 cm(sup 2). An efficiency of 26 percent was achieved for similar 0.64-cm(sup 2) concentrator cells at 150 suns. More fundamental work on dopant-diffused regions is also presented here. The recombination vs. various process and physical parameters was studied in detail for boron and phosphorous diffusions. Emitter-design studies based solidly upon these new data indicate the performance vs. design parameters for a variety of the cases of most interest to solar cell designers. Extractions of p-type bandgap narrowing and the surface recombination for p- and n-type regions from these studies have a generality that extends beyond solar cells into basic device modeling.

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

1990-11-01

309

Computer modelling of inversion layer solar cells  

Microsoft Academic Search

A model has been developed which is capable of fast, yet accurate and versatile simulation of inversion layer solar cells. Operating temperature, substrate doping, light intensity, grid geometry, cell thickness, and other parameters can be readily varied to determine their effect on collection current, output voltage, fill factor, and conversion efficiency. The model is intended to be used to study

C. E. Norman; R. E. Thomas

1978-01-01

310

High-efficiency concentrator silicon solar cells  

SciTech Connect

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% 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 demonstrated 21--22% for one-sun cells in sizes up to 37.5 cm{sup 2}. An efficiency of 26% was achieved for similar 0.64-cm{sup 2} concentrator cells at 150 suns. More fundamental work on dopant-diffused regions is also presented here. The recombination vs. various process and physical parameters was studied in detail for boron and phosphorous diffusions. Emitter-design studies based solidly upon these new data indicate the performance vs design parameters for a variety of the cases of most interest to solar cell designers. Extractions of p-type bandgap narrowing and the surface recombination for p- and n-type regions from these studies have a generality that extends beyond solar cells into basic device modeling. 68 refs., 50 figs.

Sinton, R.A.; Cuevas, A.; King, R.R.; Swanson, R.M. (Stanford Univ., CA (USA). Solid-State Electronics Lab.)

1990-11-01

311

Walking-Beam Solar-Cell Conveyor  

NASA Technical Reports Server (NTRS)

Microprocessor-controlled walking-beam conveyor moves cells between work stations in automated assembly line. Conveyor has arm at each work station. In unison arms pick up all solar cells and advance them one station; then beam retracks to be in position for next step. Microprocessor sets beam stroke, speed, and position.

Feder, H.; Frasch, W.

1982-01-01

312

Photochemical Escape of C from Mars  

NASA Astrophysics Data System (ADS)

Atomic carbon may escape from the atmosphere of Mars by a number of non-thermal mechanisms, which may be photochemical or mechanical processes, such as sputtering. We present model calculations of the escape rate of C by the photochemical escape mechanisms, including dissociative recombination of CO^+, photodissociation and photodissociative ionization of CO, electron impact dissociation and dissociative ionization of CO, and a few chemical reactions. Our background model is based on the MTGCM model of Bougher and co-workers, and the solar fluxes are from the solar flux model of Ayres. We find that the most important escape mechanism is dissociative recombination of CO^+, but photodissociation may also make a signficant contribution if the mixing ratio of CO is larger at high solar activity than at low solar activity.

Fox, Jane L.

1999-10-01

313

Photochemical Escape of C from Mars  

NASA Astrophysics Data System (ADS)

Atomic carbon may escape from the atmosphere of Mars by a number of non-thermal mechanisms, which may be photochemical or mechanical processes, such as sputtering. We present model calculations of the escape rate of C by the photochemical escape mechanisms, including dissociative recombination of CO+, photodissociation and photodissociative ionization of CO, electron impact dissociation and dissociative ionization of CO, and a few chemical reactions. Our background model is based on the MTGCM model of Bougher and co-workers, and the solar fluxes are from the solar flux model of Ayres. We find that the most important escape mechanism is dissociative recombination of CO+, but photodissociation may also make a signficant contribution if the mixing ratio of CO is larger at high solar activity than at low solar activity.

Fox, J. L.

1999-12-01

314

Mechanically stacked concentrator tandem solar cells  

NASA Technical Reports Server (NTRS)

Four-terminal mechanically stacked solar cells were developed for advanced space arrays with line-focus reflective concentrators. The top cells are based on AlGaAs/GaAs multilayer heterostructures prepared by low temperature liquid phase epitaxy. The bottom cells are based on heteroepitaxial InP/InGaAs liquid phase epitaxy or on homo-junction GaSb, Zn-diffused structures. The sum of the highest reached efficiencies of the top and bottom cells is 29.4 percent. The best four-terminal tandems have an efficiency of 27 to 28 percent. Solar cells were irradiated with 1 MeV electrons and their performances were determined as a function of fluence up to 10(exp 16) cm(exp-2). It was shown that the radiation resistance of developed tandem cells is similar to the most radiative stable AlGaAs/GaAs cells with a thin p-GaAs photoactive layer.

Andreev, V. M.; Rumyantsev, V. D.; Karlina, L. B.; Kazantsev, A. B.; Khvostikov, V. P.; Shvarts, M. Z.; Sorokina, S. V.

1995-01-01

315

Calculation of Optimally Reliable Solar Cell Arrays  

Microsoft Academic Search

Present state-of-the-art emphasis has been placed on the use of silicon solar cells interconnected in series-parallel groups to form a solar array providing basic power for long lifetime spacecraft (perhaps greater than 3 months). To assure that sufficient power will be available to operate equipments during the specified mission time, a reasonable margin must be designed into an array to

R. Brenan; F. Mason

1964-01-01

316

Printable CIGS thin film solar cells  

NASA Astrophysics Data System (ADS)

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

Fan, Xiaojuan

2013-03-01

317

Design, synthesis, photochemical properties and cytotoxic activities of water-Soluble caged l-Leucyl- l-leucine methyl esters that control apoptosis of immune cells  

Microsoft Academic Search

l-Leucyl-l-leucine methyl esters (LeuLeuOMe) is a lysosomotropic agent that induces apoptosis of certain immune cells. Glucose-carrying 2-nitrobenzyl (2-NB) and 2-nitrophenethyl (2-NPE) caged LeuLeuOMe, 1a and b, were synthesized and their photochemical and immunological properties were studied. Caged glycine methyl esters (GlyOMe), 2a,b, were also prepared to examine the cytotoxic activity of the photolytic byproducts from 1a,b. All the caged compounds

Hironori Mizuta; Soichiro Watanabe; Yuji Sakurai; Keiko Nishiyama; Toshiaki Furuta; Yoshiro Kobayashi; Michiko Iwamura

2002-01-01

318

Accelerated/abbreviated test methods for predicting life of solar cell encapsulants to Jet Propulsion Laboratory California Institute of Technology for the encapsulation task of the low-cost solar array project  

NASA Technical Reports Server (NTRS)

An important principle is that encapsulants should be tested in a total array system allowing realistic interaction of components. Therefore, micromodule test specimens were fabricated with a variety of encapsulants, substrates, and types of circuitry. One common failure mode was corrosion of circuitry and solar cell metallization due to moisture penetration. Another was darkening and/or opacification of encapsulant. A test program plan was proposed. It includes multicondition accelerated exposure. Another method was hyperaccelerated photochemical exposure using a solar concentrator. It simulates 20 year of sunlight exposure in a short period of one to two weeks. The study was beneficial in identifying some cost effective encapsulants and array designs.

Kolyer, J. M.

1978-01-01

319

Method of fabricating a solar cell array  

SciTech Connect

A first set of pre-tabbed solar cells are assembled in a predetermined array with at least part of each tab facing upward, each tab being fixed to a bonding pad on one cell and abutting a bonding pad on an adjacent cell. The cells are held in place with a first vacuum support. The array is then inverted onto a second vacuum support which holds the tabs firmly against the cell pads they abut. The cells are exposed to radiation to melt and reflow the solder pads for bonding the tab portions not already fixed to bonding pads to these pads.

Coyle, P.J.; Crouthamel, M.S.; Lazzery, A.G.

1982-12-21

320

Plasmonic ITO-free polymer solar cell.  

PubMed

The aluminum and sliver multilayered nano-grating structure is fabricated by laser interference lithography and the intervals between nanoslits is filled with modified PEDOT:PSS. The grating structured transparent electrode functions as the anti-reflection layer which not only decreases the reflected light but also increases the absorption of the active layer. The performances of P3HT:PC61BM solar cells are studied experimentally and theoretically in detail. The field intensities of the transverse magnetic (TM) and transverse electrical (TE) waves distributed in the active layer are simulated by rigorous coupled wave analysis (RCWA). The power conversion efficiency of the plasmonic ITO-free polymer solar cell can reach 3.64% which is higher than ITO based polymer solar cell with efficiency of 3.45%. PMID:24922253

Lin, Ming-Yi; Kang, Yu Ling; Chen, Yu-Cheng; Tsai, Tsung-Han; Lin, Shih-Chieh; Huang, Yi-Hsiang; Chen, Yi-Jiun; Lu, Chun-Yang; Lin, Hoang Yan; Wang, Lon A; Wu, Chung-Chih; Lee, Si-Chen

2014-03-10

321

Cutting carbon nanotubes for solar cell application  

NASA Astrophysics Data System (ADS)

This paper presents the application of cutting multiwalled carbon nanotubes (cut-MWNTs) in solar cell. Cutting of MWNTs is performed by plasma fluorination and followed by defluorination. Cut-MWNTs with lengths of 50-200 nm are incorporated in a poly(3-octylthiophene)/n-Si heterojunction solar cell. We found that a device fabricated with cut-MWNTs shows much better performance than that of a device with pristine MWNTs. The device with cut-MWNTs shows short circuit current density, open circuit voltage, fill factor, and power conversion efficiency as 7.65 mA/cm2, 0.23 V, 31%, and 0.54%, respectively. Here, we proposed that cut-MWNTs provide efficient hole transportation having a few nanometer transportation path, hence suppressing recombination. Cut-MWNTs can be the solution to the shorting and shunting effects generally observed in the MWNT solar cell.

Kalita, Golap; Adhikari, Sudip; Aryal, Hare Ram; Umeno, Masayoshi; Afre, Rakesh; Soga, Tetsuo; Sharon, Maheshwar

2008-03-01

322

Cheap and efficient plasmonic solar cell  

NASA Astrophysics Data System (ADS)

Plasmonic solar cell is a very promising structure for high efficient solar cell application. It has some unique characteristics that allow high energy localization and higher solar energy absorption. Most of the proposed designs are based on using noble metals such as gold and silver to achieve the plasmonic effect. These metals are, however, expensive and increase the cost of the solar cell. Thus, the need to propose novel and cheap material with plasmonic like effect is of prime importance. In this work we demonstrate the applications of TiN that has good plasmonic like effect over wide bandwidth. A detailed comparative study of TiN and silver in an optimized design is presented, and we report comparable TiN field localization and light scattering effects. In addition, TiN is more compatible with the CMOS fabrication technology than the conventional plasmonic metals, which can even ease the integration with other optoelectric devices. Should the electrical performance be further studied and optimized, the overall efficiency of the solar cell can be maintained and/or enhanced and total cost/watt dramatically reduced.

Khalifa, Ahmed E.; Swillam, Mohamed A.

2014-03-01

323

Space solar cell research - Problems and potential  

NASA Technical Reports Server (NTRS)

The value of a passive, maintenance-free, renewable energy source was immediately recognized in the early days of the space program, and the silicon solar cell, despite its infancy, was quickly pressed into service. Efficiencies of those early space solar arrays were low, and lifetimes shorter than hoped for, but within a decade significant advances had been made in both areas. Better performance was achieved because of a variety of factors, ranging from improvements in silicon single crystal material, to better device designs, to a better understanding of the factors that affect the performance of a solar cell in space. Chief among the latter, particularly for the mid-to-high altitude (HEO) and geosynchronous (GEO) orbits, are the effects of the naturally occurring particulate radiation environment. Although not as broadly important to the photovoltaic community at large as increased efficiency, the topic of radiation damage is critically important to use of solar cells in space, and is a major component of the NASA research program in space photovoltaics. This paper will give a brief overview of some of the opportunities and challenges for space photovoltaic applications, and will discuss some of the current reseach directed at achieving high efficiency and controlling the effects of radiation damage in space solar cells.

Flood, Dennis J.

1986-01-01

324

Self-reconfiguring solar cell system  

NASA Technical Reports Server (NTRS)

A self-reconfiguring solar cell array is disclosed wherein some of the cells are switched so that they can be either in series or in shunt within the array. This feature of series or parallel switching of cells allows the array to match the load to achieve maximum power transfer. Automatic control is used to determine the conditions for maximum power operation and to switch the array into the appropriate configuration necessary to transfer maximum power to the load.

Gruber, R. P. (inventor)

1979-01-01

325

One-sun silicon solar cell research  

Microsoft Academic Search

This report describes research for the period September 1988 to February 1990 directed at improving the performance of crystalline and polycrystalline silicon solar cells. Key results include the demonstration of 24.2 percent energy conversion efficiency for 4-sq cm crystalline cells fabricated using the development of the Passivated Emitter Cell processing sequence, the demonstration of energy conversion efficiency up to 22.4

M. A. Green; J. Zhao; A. Wang; A. W. Blakers; A. M. Milne; X. Dai; C. M. Chong; S. R. Wenham; F. Zhang; F. Yun; J. Zolper; S. Narayanan; A. B. Sproul

1991-01-01

326

Physics based simulation of dye solar cells  

Microsoft Academic Search

Dye sensitized solar cells are interesting candidates for providing a renewable, cost efficient energy source with low environmental\\u000a impact. The lack of a suitable simulation software to study basic cell properties and to optimize the cell topology is currently\\u000a one of the factors hindering their commercialization. We present in this paper a theoretical model of the entire device based\\u000a on

M. Auf der Maur; A. Gagliardi; A. Di Carlo

327

High efficiency wraparound contact solar cells /HEWACS/  

NASA Technical Reports Server (NTRS)

A cell technology, producing high efficiency wrap-around contact solar cells (HEWACS), with both electrical contacts on the back and AMO conversion efficiencies of almost 15%, is presented. A flow chart indicating the baseline process sequence along with the process changes is given. Tests checking for coating delamination and contact integrity, those measuring contact strength, and thermal cycle tests, successfully demonstrated that this cell technology is ready to be moved to the pilot production stage.

Gillanders, M.; Opjorden, R.

1980-01-01

328

InP concentrator solar cells  

Microsoft Academic Search

The design, fabrication, and characterization of high-performance, n+\\/p InP shallow-homojunction (SHJ) concentrator solar cells are described. The InP device structures were grown by atmospheric-pressure metalorganic vapor phase epitaxy (APMOVPE). A preliminary assessment of the effects of grid collection distance and emitter sheet resistance on cell performance is presented. At concentration ratios of around 100, cells with efficiencies of 21.4% AM0

J. S. Ward; M. W. Wanlass; T. J. Coutts; K. A. Emery; C. R. Osterwald

1991-01-01

329

InP concentrator solar cells  

Microsoft Academic Search

The design, fabrication, and characterization of high-performance, n(+)\\/p InP shallow-homojunction (SHJ) concentrator solar cells are described. The InP device structures were grown by atmospheric-pressure metalorganic vapor phase epitaxy. A preliminary assessment of the effects of grid-collection distance and emitter-sheet resistance on cell performance is presented. At concentration ratios of around 100, cells with efficiencies of 21.4 percent AM0 (24.3 percent

J. S. Ward; M. W. Wanlass; T. J. Coutts; K. A. Emery; C. R. Osterwald

1991-01-01

330

Large area monolithic organic solar cells  

NASA Astrophysics Data System (ADS)

Although efficiencies of > 10% have recently been achieved in laboratory-scale organic solar cells, these competitive performance figures are yet to be translated to large active areas and geometries relevant for viable manufacturing. One of the factors hindering scale-up is a lack of knowledge of device physics at the sub-module level, particularly cell architecture, electrode geometry and current collection pathways. A more in depth understanding of how photocurrent and photovoltage extraction can be optimised over large active areas is urgently needed. Another key factor suppressing conversion efficiencies in large area cells is the relatively high sheet resistance of the transparent conducting anode - typically indium tin oxide. Hence, to replace ITO with alternative transparent conducting anodes is also a high priority on the pathway to viable module-level organic solar cells. In our paper we will focus on large area devices relevant to sub-module scales - 5 cm × 5 cm monolithic geometry. We have applied a range of experimental techniques to create a more comprehensive understanding of the true device physics that could help make large area, monolithic organic solar cells more viable. By employing this knowledge, a novel transparent anode consisting of molybdenum oxide (MoOx) and silver (Ag) is developed to replace ITO and PEDOT-free large area solar cell sub-modules, acting as both a transparent window and hole-collecting electrode. The proposed architecture and anode materials are well suited to high throughput, low cost all-solution processing.

Jin, Hui; Tao, Cheng; Hambsch, Mike; Pivrikas, Almantas; Velusamy, Marappan; Aljada, Muhsen; Zhang, Yuliang; Burn, Paul L.; Meredith, Paul

2012-11-01

331

Temperature dependence of amorphous silicon solar cell PV parameters  

Microsoft Academic Search

The temperature behavior of amorphous silicon (a-Si) based solar cells was measured for cells made under different fabrication conditions and with different thermal and illumination histories. Amorphous silicon solar cells exhibit a complex temperature behavior that depends on processing history and cannot be characterized by a unique temperature coefficient as in the case of crystalline silicon solar cells. In general,

D. E. Carlson; G. Lin; G. Ganguly

2000-01-01

332

A review of high-efficiency silicon solar cells  

NASA Technical Reports Server (NTRS)

Various parameters that affect solar cell efficiency were discussed. It is not understood why solar cells produced from less expensive Czochralski (Cz) silicon are less efficient than cells fabricated from more expensive float-zone (Fz) silicon. Performance characteristics were presented for recently produced, high-efficient solar cells fabricated by Westinghouse Electric Corp., Spire Corp., University of New South Wales, and Stanford University.

Rohatgi, A.

1986-01-01

333

TACSAT-4 solar cell experiment: Advanced solar cell technologies in a high radiation environment  

Microsoft Academic Search

The TACSAT-4 Solar Cell Experiment will measure the current and voltage characteristics of advanced EMCORE BTJM solar cells thinned to 100 microns and ATJM cells under an 8.5X ENTECH Stretched Lens. TACSAT-4 will fly in a highly elliptical orbit, passing through the electron and proton belts every six hours. This orbit is expected to induce a 25% power reduction in

Phillip Jenkins; Michael Krasowski; Norman Prokop; Robert Walters; D. Spina; M. Eskenazi; R. Skalitzky; T. Duffey; B. Davis; S. Koss; S. Messenger; E. Downard; K. Crist; M. O'Neill; B. Fu; D. Bentz

2009-01-01

334

Solar cell having improved back surface reflector  

NASA Technical Reports Server (NTRS)

The operating temperature is reduced and the output of a solar cell is increased by using a solar cell which carries electrodes in a grid finger pattern on its back surface. These electrodes are sintered at the proper temperature to provide good ohmic contact. After sintering, a reflective material is deposited on the back surface by vacuum evaporation. Thus, the application of the back surface reflector is separate from the back contact formation. Back surface reflectors formed in conjunction with separate grid finger configuration back contacts are more effective than those formed by full back metallization of the reflector material.

Chai, A. T. (inventor)

1982-01-01

335

Solar cell array with lightweight support structure  

SciTech Connect

A panel comprising an aluminum honeycomb core and outer face skins of Kevlar, a bi-directional epoxy-reinforced polyparabenzamide fabric which is a thermal and electrical insulator adhering to the core and forming the opposite flat surfaces of the panel. Solar cells are glued directly to one face skin while a set of epoxy-reinforced carbon fiber stiffeners are glued to the other face skin. The composite structure has a coefficient of thermal expansion closely matching that of the solar cells providing a very lightweight and stiff structure.

Gounder, R.N.

1983-07-19

336

Solar cell contact formation using laser ablation  

SciTech Connect

The formation of solar cell contacts using a laser is described. A method of fabricating a back-contact solar cell includes forming a poly-crystalline material layer above a single-crystalline substrate. The method also includes forming a dielectric material stack above the poly-crystalline material layer. The method also includes forming, by laser ablation, a plurality of contacts holes in the dielectric material stack, each of the contact holes exposing a portion of the poly-crystalline material layer; and forming conductive contacts in the plurality of contact holes.

Harley, Gabriel; Smith, David; Cousins, Peter

2012-12-04

337

Comprehensive Silicon-Solar-Cell Program  

NASA Technical Reports Server (NTRS)

Comprehensive Silicon Solar Cell Computer Modeling (SICELL) program simulates silicon solar cell. Predicts device parameters as efficiency, voltage-vs.-current characteristic fill factor, and temperature coefficients of parameters. Technique used similar to numerical-integration methods, but commonality described by use of mesh-point field. Validation studies show accuracies of simulations range from 0.08 percent to 3.6 percent for 27 experimental data points over temperature range of 300K to 421K. Results obtained by use of 10 mesh points in n- and p-type regions and for two iterations. SICELL runs interactively on VAX computer under VMS and written in VAX/VMS FORTRAN 77.

Lamorte, Michael F.; Yeager, William M.

1989-01-01

338

Solar recharging system for hearing aid cells.  

PubMed

We present a solar recharging system for nickel-cadmium cells of interest in areas where batteries for hearing aids are difficult to obtain. The charger has sun cells at the top. Luminous energy is converted into electrical energy, during the day and also at night if there is moonlight. The cost of the charger and hearing aid is very low at 35 US$. The use of solar recharging for hearing aids would be useful in alleviating the problems of deafness in parts of developing countries where there is no electricity. PMID:7964140

Gòmez Estancona, N; Tena, A G; Torca, J; Urruticoechea, L; Muñiz, L; Aristimuño, D; Unanue, J M; Torca, J; Urruticoechea, A

1994-09-01

339

Energy Conversion: Nano Solar Cell  

Microsoft Academic Search

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

Muhammad Yahaya; Chi Chin Yap; Muhamad Mat Salleh

2009-01-01

340

Gaalas/Gaas Solar Cell Process Study  

NASA Technical Reports Server (NTRS)

Available information on liquid phase, vapor phase (including chemical vapor deposition) and molecular beam epitaxy growth procedures that could be used to fabricate single crystal, heteroface, (AlGa) As/GaAs solar cells, for space applications is summarized. A comparison of the basic cost elements of the epitaxy growth processes shows that the current infinite melt LPE process has the lower cost per cell for an annual production rate of 10,000 cells. The metal organic chemical vapor deposition (MO-CVD) process has the potential for low cost production of solar cells but there is currently a significant uncertainty in process yield, i.e., the fraction of active material in the input gas stream that ends up in the cell. Additional work is needed to optimize and document the process parameters for the MO-CVD process.

Almgren, D. W.; Csigi, K. I.

1980-01-01

341

InP concentrator solar cells  

NASA Technical Reports Server (NTRS)

The design, fabrication, and characterization of high-performance, n(+)/p InP shallow-homojunction (SHJ) concentrator solar cells are described. The InP device structures were grown by atmospheric-pressure metalorganic vapor phase epitaxy. A preliminary assessment of the effects of grid-collection distance and emitter-sheet resistance on cell performance is presented. At concentration ratios of around 100, cells with efficiencies of 21.4 percent AM0 (24.3 percent direct) at 25 C are fabricated. These are the highest efficiencies yet reported for single-junction InP solar cells. The performance of these cells as a function of temperature is discussed, and areas for future improvement are outlined. Application of these results to other InP-based photovoltaic devices is discussed.

Ward, J. S.; Wanlass, M. W.; Coutts, T. J.; Emery, K. A.; Osterwald, C. R.

1991-01-01

342

NanoSense: Solar Cell Animation  

NSDL National Science Digital Library

This Flash animation depicts the function of two types of solar cell systems: a silicon-based cell and a dye-sensitized cell. Both systems convert light energy to electrical energy, but the structure is quite different. The silicon-based cell is a solid-state semiconductor that employs two crystalline silicon layers between metal conducting strips. The dye-sensitized cell consists of a layer of titanium dioxide nanoparticles bonded to a layer of organic dye, and immersed in an electrolyte solution. Both systems excite electrons, which are directed to conducting strips and flow through a wire as electric current.

2013-04-19

343

Modifying the solar spectrum to enhance silicon solar cell efficiency—An overview of available materials  

Microsoft Academic Search

There are three ways in which the cell efficiency of silicon solar cells may be improved by better exploitation of the solar spectrum: down-conversion (cutting one high energy photon into two low energy photons), photoluminescence (shifting photons into wavelength regions better accepted by the solar cell) and up-conversion (combining low energy photons to one high energy photon). In this paper,

C. Strümpel; M. McCann; G. Beaucarne; V. Arkhipov; A. Slaoui; V. Švr?ek; C. del Cañizo; I. Tobias

2007-01-01

344

Theoretical Quantification of Nonlinear Effects in Silicon Solar Cells.  

National Technical Information Service (NTIS)

An analytic model for the internal quantum efficiency of solar cells is presented. It is especially intended for explanation and quantitative analysis of nonlinear effects in silicon solar cells. The model differs from conventional ones in that it conside...

J. M. Ruiz

1986-01-01

345

Harmful Shunting Mechanisms Found in Silicon Solar Cells (Fact Sheet)  

SciTech Connect

Scientists developed near-field optical microscopy for imaging electrical breakdown in solar cells and identified critical electrical breakdown mechanisms operating in industrial silicon and epitaxial silicon solar cells.

Not Available

2011-05-01

346

High Rate Laser Pitting Technique for Solar Cell Texturing.  

National Technical Information Service (NTIS)

High rate laser pitting technique for solar cell texturing Efficiency of crystalline silicon solar cells can be improved by creating a texture on the surface to increase optical absorption. Different techniques have been developed for texturing, with the ...

H. J. Herfurth

2011-01-01

347

Polymer-fullerene bulk heterojunction solar cells  

NASA Astrophysics Data System (ADS)

Organic solar cells have the potential to be low-cost and efficient solar energy converters, with a promising energy balance. They are made of carbon-based semiconductors, which exhibit favourable light absorption and charge generation properties, and can be manufactured by low temperature processes such as printing from solvent-based inks, which are compatible with flexible plastic substrates or even paper. In this review, we will present an overview of the physical function of organic solar cells, their state-of-the-art performance and limitations, as well as novel concepts to achieve a better material stability and higher power conversion efficiencies. We will also briefly review processing and cost in view of the market potential.

Deibel, Carsten; Dyakonov, Vladimir

2010-09-01

348

High-performance silicon nanohole solar cells.  

PubMed

We demonstrate Si nanohole arrays as a superior sunlight-absorbing nanostructure for photovoltaic solar cell applications. Under 1 sun AM1.5G illumination, a Si nanohole solar cell with p-n junctions via P diffusion exhibited a open-circuit voltage of 566.6 mV, a short-circuit current density of 32.2 mA/cm(2), and a remarkable power conversion efficiency of 9.51%, which is higher than that of its counterparts based on Si nanowires, planar Si, and pyramid-textured Si. The nanohole array geometry presents a novel and viable method fo cost-efficient solar energy conversion. PMID:20426468

Peng, Kui-Qing; Wang, Xin; Li, Li; Wu, Xiao-Ling; Lee, Shuit-Tong

2010-05-26

349

Electrical overstress failure in silicon solar cells  

SciTech Connect

A solar-cell electrical-overstress-failure model and the results of experimental measurements of threshold pulsed failure currents on four types of silicon solar cells are presented. The transient EMP field surrounding a lightning stroke has been identified as a potential threat to a photovoltaic array, yet failure analysis of solar cells in a pulsed environment had not previously been reported. Failure in the low-resistivity concentrator cells at pulse widths between 1 ..mu..s and 1 ms occurred initially in the junction. Finger damage in the form of silver melting occurs at currents only slightly greater than that required for junction damage. The result of reverse-bias transient-overstress tests on high-resistivity (10 ..cap omega..cm) cells demonstrated that the predominant failure mode was due to edge currents. These flat-plate cells failed at currents of only 4 to 20 A, which is one or two orders of magnitude below the model predictions. It thus appears that high-resistivity flat-plate cells are quite vulnerable to electrical overstress which could be produced by a variety of mechanisms.

Pease, R.L.; Barnum, J.R.; van Lint, V.A.J.; Vulliet, W.V.; Wrobel, T.F.

1982-11-01

350

Laser synthesized super-hydrophobic conducting carbon with broccoli-type morphology as a counter-electrode for dye sensitized solar cells  

NASA Astrophysics Data System (ADS)

A laser photochemical process is introduced to realize superhydrophobic conducting carbon coatings with broccoli-type hierarchical morphology for use as a metal-free counter electrode in a dye sensitized solar cell. The process involves pulsed excimer laser irradiation of a thin layer of liquid haloaromatic organic solvent o-dichlorobenzene (DCB). The coating reflects a carbon nanoparticle-self assembled and process-controlled morphology that yields solar to electric power conversion efficiency of 5.1% as opposed to 6.2% obtained with the conventional Pt-based electrode.A laser photochemical process is introduced to realize superhydrophobic conducting carbon coatings with broccoli-type hierarchical morphology for use as a metal-free counter electrode in a dye sensitized solar cell. The process involves pulsed excimer laser irradiation of a thin layer of liquid haloaromatic organic solvent o-dichlorobenzene (DCB). The coating reflects a carbon nanoparticle-self assembled and process-controlled morphology that yields solar to electric power conversion efficiency of 5.1% as opposed to 6.2% obtained with the conventional Pt-based electrode. Electronic supplementary information (ESI) available: Materials and equipment details, solar cell fabrication protocol, electrolyte spreading time measurement details, XPS spectra, electronic study, film adhesion test detailed analysis and field emission results. See DOI: 10.1039/c2nr32082g

Gokhale, Rohan; Agarkar, Shruti; Debgupta, Joyashish; Shinde, Deodatta; Lefez, Benoit; Banerjee, Abhik; Jog, Jyoti; More, Mahendra; Hannoyer, Beatrice; Ogale, Satishchandra

2012-10-01

351

Luminescent solar concentrators and all-inorganic nanoparticle solar cells for solar energy harvesting  

NASA Astrophysics Data System (ADS)

Increasing energy demand and the parallel increase of greenhouse gas emissions are challenging researchers to find new and cleaner energy sources. Solar energy harvesting is arguably the most promising candidate for replacing fossil-fuel power generation. Photovoltaics are the most direct way of collecting solar energy; cost continues to hinder large-scale implementation of photovoltaics, however. Therefore, alternative technologies that will allow the extraction of solar power, while maintaining the overall costs of fabrication, installation, collection, and distribution low, must be explored. This thesis focuses on the fabrication and testing of two types of devices that step up to this challenge: the luminescent solar concentrator (LSC) and all-inorganic nanoparticle solar cells. In these devices I make use of novel materials, semiconducting polymers and inorganic nanoparticles, both of which have lower costs than the crystalline materials used in the fabrication of traditional photovoltaics. Furthermore, the cost of manufacturing LSCs and the nanoparticle solar cells is lower than the manufacturing cost of traditional optics-based concentrators and crystalline solar cells. An LSC is essentially a slab of luminescent material that acts as a planar light pipe. The LSC absorbs incoming photons and channels fluoresced photons toward appropriately located solar cells, which perform the photovoltaic conversion. By covering large areas with relatively inexpensive fluorescing organic dyes or semiconducting polymers, the area of solar cell needed is greatly reduced. Because semiconducting polymers and quantum dots may have small absorption/emission band overlaps, tunable absorption, and longer lifetimes, they are good candidates for LSC fabrication, promising improvement with respect to laser dyes traditionally used to fabricate LSCs. Here the efficiency of LSCs consisting of liquid solutions of semiconducting polymers encased in glass was measured and compared to the efficiency of LSCs based on small molecule laser dyes and on quantum dots. Factors affecting the optical efficiency of the system such as the luminescing properties of the fluorophors were examined. The experimental results were compared to Monte-Carlo simulations. Our results suggest that commercially available quantum dots cannot serve as viable LSC dyes because of large absorption/emission band overlap and relatively low quantum yield. Materials such as Red F demonstrate that semi-conducting polymers with high quantum yield and small absorption/emission band overlap are good candidates for LSCs. Recently, a solar cell system based purely on CdSe and Cite nanoparticles as the absorbing materials was proposed ans it was suggested that its operational mechanism was that of polymer donor/acceptor systems. Here we present solar cells consisting of a sintered active bilayer of CdSe and PbSe nanoparticles in the structure ITO/CdSe/interlayer/PbSe/Al, where an interlayer of LiF or Al2O3 was found necessary to prevent low shunt resistance from suppressing the photovoltaic behavior. We fabricated unoptimized solar cells with a short-circuit current of 6 mA/cm2, an open-circuit voltage of 0.18 V, and a fill factor of 41%. External quantum efficiency spectra revealed that photons from the infrared portion of the spectrum were not collected, suggesting that the low bandgap PbSe film did not contribute to the photocurrent of the structure despite exhibiting photoconductivity. Other measurements, however, showed that the PbSe film was indeed necessary to produce a photovoltage and transport electrons. Through sintering, the nanoparticle films acquired bandgaps similar to those of the corresponding bulk materials and became more conductive. Because the PbSe films were found to be considerably more conductive than the CdSe ones, we suggest that the PbSe layer is effectively behaving like a low conductivity electrical contact. Therefore, in contrast to the photovoltaics presented in the seminal research on CdSe/Cite solar cells, the CdSe/PbSe solar cell system presented here d

Sholin, Veronica

352

Glass sealed silicon membrane solar cell  

Microsoft Academic Search

An improved silicon back surface field solar cell is described comprising a high quality very thin silicon single crystal wafer base 0.0005 to about 0.0004 inch thick. The base contains a back surface field region of the same type, P or N, as the base. The back surface field region has a thickness of about 1 m and a dopant

Mandelkorn

1987-01-01

353

Low cost silicon solar cell array  

NASA Technical Reports Server (NTRS)

The technological options available for producing low cost silicon solar cell arrays were examined. A project value of approximately $250/sq m and $2/watt is projected, based on mass production capacity demand. Recommendations are included for the most promising cost reduction options.

Bartels, F. T. C.

1974-01-01

354

Metal electrode for amorphous silicon solar cells  

DOEpatents

An amorphous silicon solar cell having an N-type region wherein the contact to the N-type region is composed of a material having a work function of about 3.7 electron volts or less. Suitable materials include strontium, barium and magnesium and rare earth metals such as gadolinium and yttrium.

Williams, Richard (Princeton, NJ)

1983-01-01

355

Fluorescent window for liquid junction solar cells  

Microsoft Academic Search

To recover part of the often substantial fraction of the sunlight lost in practical semiconductor-liquid junction solar cells by solution absorption, two designs incorporating fluorescent windows are analyzed and tested. In these schemes the luminescers absorb incident light in regions of electrolyte absorption and re-emit at wavelengths both within the semiconductor band gap and the transparent range of the solution.

M. S. Kazacos; E. J. McHenry; A. Heller; B. Miller

1980-01-01

356

Large area Czochralski silicon for solar cells  

NASA Technical Reports Server (NTRS)

A detailed model of a typical Czochralski silicon crystal puller is utilized to predict maximum crystal growth rate as a function of various furnace parameters. Results of this analysis, when combined with multiblade slurry sawing, indicate that the Czochralski process is highly attractive for achieving near-term cost reduction of solar cell silicon.

Rea, S. N.; Wakefield, G. F.

1976-01-01

357

Screen printed interdigitated back contact solar cell  

NASA Technical Reports Server (NTRS)

Interdigitated back contact solar cells are made by screen printing dopant materials onto the back surface of a semiconductor substrate in a pair of interdigitated patterns. These dopant materials are then diffused into the substrate to form junctions having configurations corresponding to these patterns. Contacts having configurations which match the patterns are then applied over the junctions.

Baraona, C. R.; Mazaris, G. A.; Chai, A. T. (inventors)

1984-01-01

358

Progress in low cost solar cells  

Microsoft Academic Search

The solar cell is a remarkable device. It converts the sun's distributed energy into electricity with 15 to 20 percent efficiency, has no moving parts, is simple in structure and in the case of silicon is made of one of the most abundant elements on earth. Such a device would give a clean, quiet source of power and an alternative

P. Rappaport

1976-01-01

359

Prepolymer Syrup for Encapsulating Solar Cells  

NASA Technical Reports Server (NTRS)

Clear polymer syrup, made by disolving n-butyl acrylate prepolymer in monomer, used to encapsulate solar cells by any of three standard processes (dipping, multiple coating, or automated machine coating). Use of cyclohexane instead of methanol/water solvent during initial polymerization stage maintains high molecular weight and raises yield of linear polymer to essentially 100 percent.

Gupta, A.; Ingham, J. D.; Yavrouian, A. H.

1982-01-01

360

Fatigue Properties of Solar Cell Interconnectors.  

National Technical Information Service (NTIS)

A test rig was developed to evaluate the fatigue properties of molybdenum and silver mesh solar cell interconnectors at temperatures of -130 C and -170 C. The rig consists of an electromagnetic vibrator and a specimen clamping system and is operated using...

R. B. Evans S. Stevens P. Campbell

1977-01-01

361

A Photoelectrochemical Solar Cell: An Undergraduate Experiment.  

ERIC Educational Resources Information Center

Preparation and testing of a cadmium selenide photoelectrical solar cell was introduced into an environmental chemistry course to illustrate solid state semiconductor and electrochemical principles. Background information, procedures, and results are provided for the experiment which can be accomplished in a three- to four-hour laboratory session…

Boudreau, Sharon M.; And Others

1983-01-01

362

Comprehensive solar cell modeling and correlation studies  

NASA Technical Reports Server (NTRS)

Modeling and correlation studies of solar cells was discussed. Recursive relationships were used to generate solutions at a number of mesh points within the emitter region. Photoexcited hole concentration and built-in electric field were calculated as a function of position. Simulated and experimentally determined I-V curves were shown to have good fit.

Lamorte, M. L.

1985-01-01

363

Texturing industrial multicrystalline silicon solar cells  

Microsoft Academic Search

Three potential techniques for texturing commercial multicrystalline silicon solar cells are compared on the basis of reflectance measurements. Wet acidic texturing, which would be the least costly to implement, produces a modest improvement in reflection before antireflection coating and encapsulation, whereas maskless reactive-ion etching texturing, and especially masked reactive-ion etched ‘pyramids’, generate a larger gain in absorption. After antireflection coating

D. H. Macdonald; A. Cuevas; M. J. Kerr; C. Samundsett; D. Ruby; S. Winderbaum; A. Leo

2004-01-01

364

Tandem junction amorphous silicon solar cells  

DOEpatents

An amorphous silicon solar cell has an active body with two or a series of layers of hydrogenated amorphous silicon arranged in a tandem stacked configuration with one optical path and electrically interconnected by a tunnel junction. The layers of hydrogenated amorphous silicon arranged in tandem configuration can have the same bandgap or differing bandgaps.

Hanak, Joseph J. (Lawrenceville, NJ)

1981-01-01

365

Hybrid silicon nanocone-polymer solar cells.  

PubMed

Recently, hybrid Si/organic solar cells have been studied for low-cost Si photovoltaic devices because the Schottky junction between the Si and organic material can be formed by solution processes at a low temperature. In this study, we demonstrate a hybrid solar cell composed of Si nanocones and conductive polymer. The optimal nanocone structure with an aspect ratio (height/diameter of a nanocone) less than two allowed for conformal polymer surface coverage via spin-coating while also providing both excellent antireflection and light trapping properties. The uniform heterojunction over the nanocones with enhanced light absorption resulted in a power conversion efficiency above 11%. Based on our simulation study, the optimal nanocone structures for a 10 ?m thick Si solar cell can achieve a short-circuit current density, up to 39.1 mA/cm(2), which is very close to the theoretical limit. With very thin material and inexpensive processing, hybrid Si nanocone/polymer solar cells are promising as an economically viable alternative energy solution. PMID:22545674

Jeong, Sangmoo; Garnett, Erik C; Wang, Shuang; Yu, Zongfu; Fan, Shanhui; Brongersma, Mark L; McGehee, Michael D; Cui, Yi

2012-06-13

366

Physics based simulation of dye solar cells  

Microsoft Academic Search

Dye sensitized solar cells (DSCs) are interesting candidates for providing a renewable, cost efficient energy source with low environmental impact. Although DSCs are very close to be commercialized, many issues still need to be addressed. Part of the problem is related to the lack of a reliable and consistent simulator able to catch the physics underlying the functioning of the

M. Auf der Maur; A. Gagliardi; A. Di Carlo

2010-01-01

367

Metalizing Solar Cells by Selective Electroplating  

NASA Technical Reports Server (NTRS)

Contact patterns traced by laser scanning. Conductor paths deposited on silicon solar-cell wafers by laser irradiation followed by electroplating. Laser-assisted metalization technique offers better resolution and lower contact resistance than does conventional metalization by screen printing. At the same time, less expensive than metalization with masks and photolithography.

Dutta, S.; Palaschak, P. A.

1986-01-01

368

Aluminum doping improves silicon solar cells  

NASA Technical Reports Server (NTRS)

Aluminum doped silicon solar cells with resistivities in the 10- to 20-ohm centimeter range have broad spectral response, high efficiency and long lifetimes in nuclear radiation environments. Production advantages include low material rejection and increased production yields, and close tolerance control.

1966-01-01

369

Assembly jig assures reliable solar cell modules  

NASA Technical Reports Server (NTRS)

Assembly jig holds the components for a solar cell module in place as the assembly is soldered and bonded by the even heat of an oven. The jig is designed to the configuration of the planned module. It eliminates uneven thermal conditions caused by hand soldering methods.

Ofarrell, H. O.

1966-01-01

370

Amorphous silicon nanocone array solar cell  

PubMed Central

In the hydrogenated amorphous silicon [a-Si:H]-thin film solar cell, large amounts of traps reduce the carrier's lifetime that limit the photovoltaic performance, especially the power conversion efficiency. The nanowire structure is proposed to solve the low efficiency problem. In this work, we propose an amorphous silicon [a-Si]-solar cell with a nanocone array structure were implemented by reactive-ion etching through a polystyrene nanosphere template. The amorphous-Si nanocone exhibits absorption coefficient around 5 × 105/cm which is similar to the planar a-Si:H layer in our study. The nanostructure could provide the efficient carrier collection. Owing to the better carrier collection efficiency, efficiency of a-Si solar cell was increased from 1.43% to 1.77% by adding the nanocone structure which has 24% enhancement. Further passivation of the a-Si:H surface by hydrogen plasma treatment and an additional 10-nm intrinsic-a-Si:H layer, the efficiency could further increase to 2.2%, which is 54% enhanced as compared to the planar solar cell. The input-photon-to-current conversion efficiency spectrum indicates the efficient carrier collection from 300 to 800 nm of incident light.

2012-01-01

371

Compensated amorphous-silicon solar cell  

Microsoft Academic Search

An amorphous silicon solar cell including an electrically conductive substrate, a layer of glow discharge deposited hydrogenated amorphous silicon 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 elecrically conductive substrate and an electrode

Devaud

1982-01-01

372

High efficiency double sided solar cells.  

National Technical Information Service (NTIS)

Silicon technology state of the art for single crystalline was given to be limited to less than 20% efficiency. A proposed new form of photovoltaic solar cell of high current high efficiency with double sided structures has been given. The new forms could...

M. M. Seddik

1990-01-01

373

Computer modeling of high intensity solar cells  

Microsoft Academic Search

The purpose of this program is to provide general analytic support to Sandia National Laboratories' effort to develop high efficiency, high concentration solar cells. This report covers work performed between November 5, 1984, and December 31, 1985, and includes reprints of three papers presented at the 18th IEEE Photovoltaic Specialists' Conference. In the first paper, the factors that presently prevent

J. L. Gray; M. S. Lundstrom; R. J. Schwartz

1987-01-01

374

Concentrator Solar-Cell Flash Tester.  

National Technical Information Service (NTIS)

A method is described for testing solar cells at high concentrations in a laboratory environment without the need of coolant loops, precision tracking apparatus or dependence on cloud-free days. A complete Voltage-Current (V-I) characteristic curve for a ...

R. E. Hibray

1982-01-01

375

High-Temperature Solar Cell Development.  

National Technical Information Service (NTIS)

The vast majority of satellites and near-earth probes developed to date have relied upon photovoltaic power generation. If future missions to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high...

G. A. Landis R. P. Raffaelle D. Merritt

2004-01-01

376

Silicon Solar Cell Development for Concentrator Applications.  

National Technical Information Service (NTIS)

The objective of this work is to optimize the design of, and to develop the fabrication process for single-crystal silicon solar cells for applications at illumination levels up to approximately 100 suns and operating temperatures up to approximately 100 ...

J. G. Fossum E. L. Burgess

1977-01-01

377

Studies of silicon pn junction solar cells  

NASA Technical Reports Server (NTRS)

Modifications of the basic Shockley equations that result from the random and nonrandom spatial variations of the chemical composition of a semiconductor were developed. These modifications underlie the existence of the extensive emitter recombination current that limits the voltage over the open circuit of solar cells. The measurement of parameters, series resistance and the base diffusion length is discussed. Two methods are presented for establishing the energy bandgap narrowing in the heavily-doped emitter region. Corrections that can be important in the application of one of these methods to small test cells are examined. Oxide-charge-induced high-low-junction emitter (OCI-HLE) test cells which exhibit considerably higher voltage over the open circuit than was previously seen in n-on-p solar cells are described.

Lindholm, F. A.; Neugroschel, A.

1977-01-01

378

Light trapping in ultrathin plasmonic solar cells.  

PubMed

We report on the design, fabrication, and measurement of ultrathin film a-Si:H solar cells with nanostructured plasmonic back contacts, which demonstrate enhanced short circuit current densities compared to cells having flat or randomly textured back contacts. The primary photocurrent enhancement occurs in the spectral range from 550 nm to 800 nm. We use angle-resolved photocurrent spectroscopy to confirm that the enhanced absorption is due to coupling to guided modes supported by the cell. Full-field electromagnetic simulation of the absorption in the active a-Si:H layer agrees well with the experimental results. Furthermore, the nanopatterns were fabricated via an inexpensive, scalable, and precise nanopatterning method. These results should guide design of optimized, non-random nanostructured back reflectors for thin film solar cells. PMID:20588593

Ferry, Vivian E; Verschuuren, Marc A; Li, Hongbo B T; Verhagen, Ewold; Walters, Robert J; Schropp, Ruud E I; Atwater, Harry A; Polman, Albert

2010-06-21

379

Passivated emitters in silicon solar cells  

NASA Astrophysics Data System (ADS)

In high-efficiency silicon solar cells with low metal contact coverage fractions and high bulk lifetimes, cell performance is often dominated by recombination in the oxide-passivated diffusions on the cell surface. Measurements of the emitter saturation current density, Jo, of oxide-passivated, boron and phosphorus diffusions are presented, and from these measurements, the dependence of surface recombination velocity on dopant concentration is extracted. The lowest observed values of Jo which are stable under UV light are given for both boron- and phosphorus-doped, oxide-passivated diffusions, for both textured and untextured surfaces. Contour plots which incorporate the above data were applied to two types of backside-contact solar cells with large area (37.5 sq cm) and one-sun efficiencies up to 22.7 percent.

King, Richard R.; Gruenbaum, Peter E.; Sinton, Ronald A.; Swanson, Richard M.

380

Direct-Write Contacts for Solar Cells  

SciTech Connect

We report on our project to develop inkjet printable contacts for solar cells. Ag, Cu, and Ni metallizations were inkjet printed with near vacuum deposition quality. Thick, highly conducting lines of Ag and Cu demonstrating good adhesion to glass, Si, and PCB have been printed at 100-200 C in air and N2, respectively. Ag grids were inkjet-printed on Si solar cells and fired through silicon nitride AR layer at 850 C resulting in 8% cells. Next-generation multicomponent inks (including etching agents) have also been developed with improved fire-through contacts leading to higher cell efficiencies. The approach developed can be easily extended to other conductors such as Pt, Pd, and Au, etc. In addition, PEDOT-PSS polymer-based conductors were inkjet-printed with the conductivity as good or better than those of polymer-based conductors.

Kaydanova, T.; van Hest, M.F.A.M.; Miedaner, A.; Curtis, C. J.; Alleman, J. L.; Dabney, M. S.; Garnett, E.; Shaheen, S.; Ginley, D. S.; Smith, L.; Collins, R.; Hanoka, J. I.; Gabor, A. M.

2005-01-01

381

LARGE AREA METALLISATION WRAP THROUGH SOLAR CELLS WITH THICKFILM METALLISATION  

Microsoft Academic Search

Metallization Wrap Through (MWT) solar cells are back contact solar cells that can be processed with only a little extra effort compared to conventional cells. The cell concept is particularly suited for large area cells, which makes the concept attractive, since the size of the wafers processed by the industry is increasing. The MWT cells presented in this paper are

H. Knauss; P. Fath; W. Jooss; M. McCann; E. Rüland; S. Steckemetz

382

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

383

Laser scanning of experimental solar cells  

Microsoft Academic Search

A description is presented of a laser scanning instrument which makes it possible to display and measure the spatial response of a solar cell. Examples are presented to illustrate the use of generated micrographs in the isolation of flaws and features of the cell. The laser scanner system uses a 4 mW, CW helium-neon laser, operating a wavelength of 0.633

B. C. Plunkett; P. G. Lasswell

1980-01-01

384

Status of silicon solar cell technology  

NASA Technical Reports Server (NTRS)

Major progress in solar cell technology leading to increased efficiency has occurred since 1970. Technical approaches leading to this increased output include surface texturing, improved antireflection coatings, reduced grid pattern area coverage, shallow junctions and back surface fields. The status of these developments and their incorporation into cell production is discussed. Future research and technology trends leading to further efficiency increases and substantial cost reductions are described.

Brandhorst, H. W., Jr.

1976-01-01

385

High-efficiency silicon solar cells  

Microsoft Academic Search

Silicon solar cells are described which operate at energy conversion efficiencies independently measured at 18.7 percent under standard terrestrial test conditions (AM1.5, 100 mW\\/cm², 28°C). These are apparently the most efficient silicon cells fabricated to date. The high-efficiency results from a combination of high open-circuit voltage due to the careful attention paid to the passivation of the top surface of

M. A. Green; A. W. Blakers; Jiqun Shi; E. M. Keller; S. R. Wenham

1984-01-01

386

Copper metallization for crystalline Si solar cells  

Microsoft Academic Search

Cu metallization for crystalline Si solar cells was investigated using either Ti or Ti\\/TiN diffusion barriers. The resistivity and the specific contact resistance change were measured for both Ti(30nm)\\/Cu(100nm) and Ti(30nm)\\/TiN(30nm)\\/Cu(100nm) contact structures under various annealing conditions. As the annealing temperature increased, the efficiency of the cells increased mainly due to the increase in fill-factor and ISC, which was correlated

JaeSung You; Jinmo Kang; Donghwan Kim; James Jungho Pak; Choon Sik Kang

2003-01-01

387

Recent developments in thin film solar cells  

Microsoft Academic Search

The present status of the development of thin film solar cells is reviewed, with emphasis on important areas for further research. The following aperture-area efficiencies were measured for thin film modules: a-Si:H, 9.8 percent, 933 sq cm; CuIn(Ga)Se2, 11.1 percent, 938 sq cm; and CdTe, 7.3 percent, 838 sq cm. CuIn(Ga)Se2 cells and modules demonstrated excellent efficiencies and stability. The

Neelkanth G. Dhere

1990-01-01

388

Recent progress in aSi solar cells  

Microsoft Academic Search

As concern regarding global environmental problems such as the greenhouse effect and acid rain has increased, so too has the demand for commercially viable solar cells as a clean energy source. Interest in amorphous silicon (a-Si) solar cells has been particulary high, due to their low cost. Technological developments in the field of a-Si solar cells are discussed from the

Shinya Tsuda; Souichi Sakai; Shoichi Nakano

1997-01-01

389

Diagnostic structures for epitaxial thin silicon solar cells  

Microsoft Academic Search

The value of a high performance thin silicon solar cell is based on high open circuit voltage (Voc) which is highly dependent upon surface and interface recombination. A microelectronic approach with the series and parallel fabrication of different device structures is presented. This approach includes the fabrication of planar solar cells based on different solar cell designs that maximize Voc.

C. Paola Murcia; Ruiying Hao; Tim Creazzo; Kevin Shreve; Anthony Lochtefeld; Michael Curtin; Allen Barnett

2010-01-01

390

Solar cell panel crack detection using Particle Swarm Optimization algorithm  

Microsoft Academic Search

A solar cell panel as an efficient power source for the production of electrical energy has long been considered. Any defect on the solar cell panel's surface will be lead to reduced production of power and loss in the yield. In this case, inspection of the solar cell panel is essential to be performed to obtain a product of high

Amir Hossein Aghamohammadi; Anton Satria Prabuwono; Shahnorbanun Sahran; Marzieh Mogharrebi

2011-01-01

391

Business, market and intellectual property analysis of polymer solar cells  

Microsoft Academic Search

The business potential of polymer solar cells is reviewed and the market opportunities analyzed on the basis of the currently reported and projected performance and manufacturing cost of polymer solar cells. Possible new market areas are identified and described. An overview of the present patent and intellectual property situation is also given and a patent map of polymer solar cells

Torben D. Nielsen; Craig Cruickshank; Søren Foged; Jesper Thorsen; Frederik C. Krebs

2010-01-01

392

Silvaco ATLAS as a solar cell modeling tool  

Microsoft Academic Search

This paper presents research efforts conducted at the Naval Postgraduate School in the development of an accurate, physically-based solar cell model using the general-purpose ATLAS device simulator by Silvaco International. Unlike solar cell models based on a combination of discrete electrical components, this novel model extracts the electrical characteristics of a solar cell based on virtual fabrication of its physical

S. Michael; A. D. Bates; M. S. Green

2005-01-01

393

Space Radiation Effects in Advanced Solar Cell Materials and Devices  

Microsoft Academic Search

An investigation of the physical mechanisms governing the response of III-V based solar cells to particle irradiation is presented. The effect of particle irradiation on single and multijunction solar cells is studied through current vs. voltage, spectral response, and deep level transient spectroscopy measurements. The basic radiation response mechanisms are identified, and their effects on the solar cell electrical performance

R. J. Walters; G. P. Summers

394

Solar cell radiation handbook. Addendum 1: 1982-1988  

NASA Technical Reports Server (NTRS)

The Solar Cell Radiation Handbook (JPL Publication 82-69) is updated. In order to maintain currency of solar cell radiation data, recent solar cell designs have been acquired, irradiated with 1 MeV electrons, and measured. The results of these radiation experiments are reported.

Anspaugh, Bruce E.

1989-01-01

395

Flexible thermal cycle test equipment for concentrator solar cells  

DOEpatents

A system and method for performing thermal stress testing of photovoltaic solar cells is presented. The system and method allows rapid testing of photovoltaic solar cells under controllable thermal conditions. The system and method presents a means of rapidly applying thermal stresses to one or more photovoltaic solar cells in a consistent and repeatable manner.

Hebert, Peter H. (Glendale, CA); Brandt, Randolph J. (Palmdale, CA)

2012-06-19

396

PN junction fabrication of solar cells and integration with metamaterials  

Microsoft Academic Search

Silicon is the primary material used for the fabrication of solar cells and it is responsible for about 40% of the cost. Metamaterials show promise in enhancing the performance of silicon solar cells thus, improving the efficiency. Here we report on the fabrication of a broadband, antireflective, conductive metamaterial capable of channeling light into a solar cell. As a precursor

Amarachukwu Enemuo; David T. Crouse; Michael Crouse

2011-01-01

397

Micro Solar Cells with Concentration and Light Trapping Optics  

NASA Astrophysics Data System (ADS)

Compared with conventional bulk plate semiconductor solar cells, micro solar cells provide opportunity for novel design geometry and provide test bed for light trapping at the device level as well as module level. Surface recombination, however, will have to be addressed properly as the much increased surface area due to the reduced dimension is more prominent in these devices than conventional solar cells. In this poster, we present experimental demonstration of silicon micro solar cells with concentration and light trapping optics. Silicon micro solar cell with optimized surface passivation and doping profile that exhibit high efficiency is demonstrated. Effective incorporation of high quantum yield fluorescent centers in the polymer matrix into which micro solar cell was encapsulated was investigated for luminescent solar concentration application. Micro-cell on a semi-transparent, nanopatterned reflector formed by soft-imprint lithography was investigated for near field effect related solar conversion performance enhancement.

Li, Lanfang; Breuckner, Eric; Corcoran, Christopher; Yao, Yuan; Xu, Lu; Nuzzo, Ralph

2013-03-01

398

High efficiency crystalline silicon solar cells  

NASA Technical Reports Server (NTRS)

A review of the entire research program since its inception ten years ago is given. The initial effort focused on the effects of impurities on the efficiency of silicon solar cells to provide figures of maximum allowable impurity density for efficiencies up to about 16 to 17%. Highly accurate experimental techniques were extended to characterize the recombination properties of the residual imputities in the silicon solar cell. A numerical simulator of the solar cell was also developed, using the Circuit Technique for Semiconductor Analysis. Recent effort focused on the delineation of the material and device parameters which limited the silicon efficiency to below 20% and on an investigation of cell designs to break the 20% barrier. Designs of the cell device structure and geometry can further reduce recombination losses as well as the sensitivity and criticalness of the fabrication technology required to exceed 20%. Further research is needed on the fundamental characterization of the carrier recombination properties at the chemical impurity and physical defect centers. It is shown that only single crystalline silicon cell technology can be successful in attaining efficiencies greater than 20%.

Sah, C. Tang

1986-01-01

399

Nanocluster production for solar cell applications  

SciTech Connect

This research focuses on the fabrication and characterization of silver (Ag) and silicon (Si) nanoclusters that might be used for solar cell applications. Silver and silicon nanoclusters have been synthesized by means of dc magnetron sputtering and inert gas condensation inside an ultra-high vacuum compatible system. We have found that nanocluster size distributions can be tuned by various source parameters, such as the sputtering discharge power, flow rate of argon inert gas, and aggregation length. Quadrupole mass filter and transmission electron microscopy were used to evaluate the size distribution of Ag and Si nanoclusters. Ag nanoclusters with average size in the range of 3.6–8.3 nm were synthesized (herein size refers to the nanocluster diameter), whereas Si nanoclusters' average size was controlled to range between 2.9 and 7.4 nm by controlling the source parameters. This work illustrates the ability of controlling the Si and Ag nanoclusters' sizes by proper optimization of the operation conditions. By controlling nanoclusters' sizes, one can alter their surface properties to suit the need to enhance solar cell efficiency. Herein, Ag nanoclusters were deposited on commercial polycrystalline solar cells. Short circuit current (I{sub SC}), open circuit voltage (V{sub OC}), fill factor, and efficiency (?) were obtained under light source with an intensity of 30 mW/cm{sup 2}. A 22.7% enhancement in solar cell efficiency could be measured after deposition of Ag nanoclusters, which demonstrates that Ag nanoclusters generated in this work are useful to enhance solar cell efficiency.

Al Dosari, Haila M.; Ayesh, Ahmad I. [Department of Physics, United Arab Emirates University, P. O. Box 15551, Al Ain (United Arab Emirates)] [Department of Physics, United Arab Emirates University, P. O. Box 15551, Al Ain (United Arab Emirates)

2013-08-07

400

Photochemical Energy Conversion.  

ERIC Educational Resources Information Center

Describes procedures for two demonstrations: (1) photochemical energy conversion using ferric oxalate actinometry and (2) liquification of gases using Freon 114. Safety precautions are given for both demonstrations, as are procedures and material specifications. (JM)

Batschelet, William H.; George, Arnold

1986-01-01

401

Photochemical Reactivity of Perchloroethylene.  

National Technical Information Service (NTIS)

Perchloroethylene (PCE), a solvent used in dry cleaning, has been suspected of contributing significantly to photochemical ozone/oxidant (O3/Ox) problems in urban atmospheres. Past evidence, however, was neither complete nor consistent. To interpret more ...

B. Dimitriades B. W. Gay R. R. Arnts R. L. Seila

1983-01-01

402

Plastic Schottky barrier solar cells  

DOEpatents

A photovoltaic cell structure is fabricated from an active medium including an undoped, intrinsically p-type organic semiconductor comprising polyacetylene. When a film of such material is in rectifying contact with a magnesium electrode, a Schottky-barrier junction is obtained within the body of the cell structure. Also, a gold overlayer passivates the magnesium layer on the undoped polyacetylene film.

Waldrop, James R. (Thousand Oaks, CA); Cohen, Marshall J. (Thousand Oaks, CA)

1984-01-24

403

Experimental and simulation analysis of the dye sensitized solar cell\\/Cu(In,Ga)Se 2 solar cell tandem structure  

Microsoft Academic Search

A novel tandem structure composed of dye sensitized solar cell (DSC) and CuInGaSe2 (CIGS) solar cell shows the potential to increase conversion efficiency by fully utilizing the sunlight. In our research, a tandem solar cell with a high open-circuit voltage of 1.15V and a conversion efficiency of 10.46%, which is both larger than that of DSC and CIGS solar cell

W. L. Wang; H. Lin; J. Zhang; X. Li; A. Yamada; M. Konagai; J. B. Li

2010-01-01

404

Enhancing Solar Cell Efficiencies through 1-D Nanostructures  

PubMed Central

The current global energy problem can be attributed to insufficient fossil fuel supplies and excessive greenhouse gas emissions resulting from increasing fossil fuel consumption. The huge demand for clean energy potentially can be met by solar-to-electricity conversions. The large-scale use of solar energy is not occurring due to the high cost and inadequate efficiencies of existing solar cells. Nanostructured materials have offered new opportunities to design more efficient solar cells, particularly one-dimensional (1-D) nanomaterials for enhancing solar cell efficiencies. These 1-D nanostructures, including nanotubes, nanowires, and nanorods, offer significant opportunities to improve efficiencies of solar cells by facilitating photon absorption, electron transport, and electron collection; however, tremendous challenges must be conquered before the large-scale commercialization of such cells. This review specifically focuses on the use of 1-D nanostructures for enhancing solar cell efficiencies. Other nanostructured solar cells or solar cells based on bulk materials are not covered in this review. Major topics addressed include dye-sensitized solar cells, quantum-dot-sensitized solar cells, and p-n junction solar cells.

2009-01-01

405

Hypervelocity Impact Studies on Solar Cell Modules  

NASA Technical Reports Server (NTRS)

Space environmental effects have caused severe problems as satellites move toward increased power and operating voltage levels. The greatest unknown, however, is the effect of high velocity micrometeoroid impacts on high voltage arrays (>200V). Understanding such impact phenomena is necessary for the design of future reliable, high voltage solar arrays, especially for Space Solar Power applications. Therefore, the objective of this work was to study the effect of hypervelocity impacts on high voltage solar arrays. Initially, state of the art, 18% efficient GaAs solar cell strings were targeted. The maximum bias voltage on a two-cell string was -200 V while the adjacent string was held at -140 V relative to the plasma potential. A hollow cathode device provided the plasma. Soda lime glass particles 40-120 micrometers in diameter were accelerated in the Hypervelocity Impact Facility to velocities as high as 11.6 km/sec. Coordinates and velocity were obtained for each of the approximately 40 particle impact sites on each shot. Arcing did occur, and both discharging and recharging of arcs between the two strings was observed. The recharging phenomena appeared to stop at approximately 66V string differential. No arcing was observed at 400 V on concentrator cell modules for the Stretched Lens Array.

Brandhorst, Henry W., Jr.; Best, Stevie R.

2001-01-01

406

Space solar cell technology development - A perspective  

NASA Technical Reports Server (NTRS)

The developmental history of photovoltaics is examined as a basis for predicting further advances to the year 2000. Transistor technology was the precursor of solar cell development. Terrestrial cells were modified for space through changes in geometry and size, as well as the use of Ag-Ti contacts and manufacture of a p-type base. The violet cell was produced for Comsat, and involved shallow junctions, new contacts, and an enhanced antireflection coating for better radiation tolerance. The driving force was the desire by private companies to reduce cost and weight for commercial satellite power supplies. Liquid phase epitaxial (LPE) GaAs cells are the latest advancement, having a 4 sq cm area and increased efficiency. GaAs cells are expected to be flight ready in the 1980s. Testing is still necessary to verify production techniques and the resistance to electron and photon damage. Research will continue in CVD cell technology, new panel technology, and ultrathin Si cells.

Scott-Monck, J.

1982-01-01

407

Solar Airplanes and Regenerative Fuel Cells  

NASA Technical Reports Server (NTRS)

A solar electric aircraft with the potential to "fly forever" has captured NASA's interest, and the concept for such an aircraft was pursued under Aeronautics Environmental Research Aircraft and Sensor Technology (ERAST) project. Feasibility of this aircraft happens to depend on the successful development of solar power technologies critical to NASA's Exploration Initiatives; hence, there was widespread interest throughout NASA to bring these technologies to a flight demonstration. The most critical is an energy storage system to sustain mission power during night periods. For the solar airplane, whose flight capability is already limited by the diffuse nature of solar flux and subject to latitude and time of year constraints, the feasibility of long endurance flight depends on a storage density figure of merit better than 400-600 watt-hr per kilogram. This figure of merit is beyond the capability of present day storage technologies (other than nuclear) but may be achievable in the hydrogen-oxygen regenerative fuel cell (RFC). This potential has led NASA to undertake the practical development of a hydrogen-oxygen regenerative fuel cell, initially as solar energy storage for a high altitude UAV science platform but eventually to serve as the primary power source for NASAs lunar base and other planet surface installations. Potentially the highest storage capacity and lowest weight of any non-nuclear device, a flight-weight RFC aboard a solar-electric aircraft that is flown continuously through several successive day-night cycles will provide the most convincing demonstration that this technology's widespread potential has been realized. In 1998 NASA began development of a closed cycle hydrogen oxygen PEM RFC under the Aeronautics Environmental Research Aircraft and Sensor Technology (ERAST) project and continued its development, originally for a solar electric airplane flight, through FY2005 under the Low Emissions Alternative Power (LEAP) project. Construction of the closed loop system began in 2002 at the NASA Glenn Research Center in Cleveland, Ohio. System checkout was completed, and testing began, in July of 2003. The initial test sequences were done with only a fuel cell or electrolyzer in the test rig. Those tests were used to verify the test apparatus, procedures, and software. The first complete cycles of the fully closed loop, regenerative fuel cell system were successfully completed in the following September. Following some hardware upgrades to increase reactant recirculation flow, the test rig was operated at full power in December 2003 and again in January 2004. In March 2004 a newer generation of fuel cell and electrolyzer stacks was substituted for the original hardware and these stacks were successfully tested at full power under cyclic operation in June of 2004.

Bents, David J.

2007-01-01

408

Labeling Solar-Cell Modules  

NASA Technical Reports Server (NTRS)

Photocopying machine produces durable identification label. Process used for double glass photovoltaic-cell modules. Matrix of cells sandwiched between thin, flexible glass mats and covered above and below by protective sheets of glass. Label contains such information as manufacturer, model number, voltage and power ratings, and serial number. May also contain electrical-shock hazard warning and identification of positive and negative terminals. Method saves expense of procuring and applying conventional labels.

Watson, E. G.; Coyle, P. J.

1984-01-01

409

Production technology for high efficiency ion implanted solar cells  

NASA Technical Reports Server (NTRS)

Ion implantation is being developed for high volume automated production of silicon solar cells. An implanter designed for solar cell processing and able to properly implant up to 300 4-inch wafers per hour is now operational. A machine to implant 180 sq m/hr of solar cell material has been designed. Implanted silicon solar cells with efficiencies exceeding 16% AM1 are now being produced and higher efficiencies are expected. Ion implantation and transient processing by pulsed electron beams are being integrated with electrostatic bonding to accomplish a simple method for large scale, low cost production of high efficiency solar cell arrays.

Kirkpatrick, A. R.; Minnucci, J. A.; Greenwald, A. C.; Josephs, R. H.

1978-01-01

410

A dye-sensitized solar cell driven electrochromic device  

Microsoft Academic Search

A new dye-sensitized solar cell driven electrochromic device has been fabricated. The device consists of an electrochromic display and a solar cell in a single nanocrystalline film. The optimization of the electrochromic and the solar cell functions was carried out. An applied potential of 1.0 V was required for coloring and the best solar energy conversion efficiency 1.1% was achieved.

Henriette Santa-Nokki; Jani Kallioinen; Jouko Korppi-Tommola

2007-01-01

411

Thin foil silicon solar cells with coplanar back contacts  

NASA Technical Reports Server (NTRS)

To fabricate 50 microns thick, coplanar back contact (CBC) silicon solar cells, wraparound junction design was selected and proved to be effective. The process sequence used, the cell design, and the cell performance are described. CBC cells with low solar absorptance have shown AMO efficiencies to 13%, high cells up to 14%; further improvements are projected with predictable optimization.

Ho, F.; Iles, P. A.; Baraona, C. R.

1981-01-01

412

Development of integral covers on solar cells  

NASA Technical Reports Server (NTRS)

The electron-beam technique for evaporating a dielectric material onto solar cells is investigated. A process has been developed which will provide a highly transparent, low stress, 2 mil thick cover capable of withstanding conventional space type qualification tests including humidity, thermal shock, and thermal cycling. The covers have demonstrated the ability to withstand 10 to the 15th power 1 MeV electrons and UV irradiation with minor darkening. Investigation of the cell AR coating has produced a space qualifiable titanium oxide coating which will give an additional 6% current output over similar silicon oxide coated cells when covered by glass.

Stella, P.; Somberg, H.

1971-01-01

413

Thermal runaway in multijunction solar cells  

NASA Astrophysics Data System (ADS)

A small fraction of GaInP2/GaAs/Ge triple junction solar cells exposed to the 6× concentrated air mass zero spectrum at 523 K for 5 min was found to be severely shunted afterwards. A combination of electroluminescence imaging and focused ion beam cross sectioning revealed that pre-existing top-middle cell shunts were responsible for the observed degradation. Joule heating in the shunt resistance limiting Ge substrate is modeled and exhibits a thermal runaway effect above a critical voltage, in agreement with the experimental observation. The implications for current and future multijunction cells are discussed.

Zimmermann, Claus G.

2013-06-01

414

Advanced high efficiency wraparound contact solar cell  

NASA Technical Reports Server (NTRS)

A significant advancement in the development of thin high efficiency wraparound contact silicon solar cells has been made by coupling space and terrestrial processing procedures. Although this new method for fabricating cells has not been completely reduced to practice, some of the initial cells have delivered over 20 mW/sq cm when tested at 25 C under AMO intensity. This approach not only yields high efficiency devices, but shows promise of allowing complete freedom of choice in both the location and size of the wraparound contact pad area.

Scott-Monck, J. A.; Uno, F. M.; Thornhill, J. W.

1977-01-01

415

Advanced high efficiency wraparound contact solar cell  

NASA Technical Reports Server (NTRS)

A significant advancement in the development of thin high efficiency wraparound contact silicon solar cells has been made by coupling space and terrestrial processing procedures. Although this new method for fabricating cells has not been completely reduced to practice, some of the initial cells have delivered over 20 mW/sq cm when tested at 25 C under AMO intensity. This approach not only yields high efficiency devices, but shows promise of allowing complete freedom of choice in both the location and size of the wraparound contact pad area

Scott-Monck, J. A.; Uno, F. M.; Thornhill, J. W.

1977-01-01

416

Multijunction high voltage concentrator solar cells  

NASA Technical Reports Server (NTRS)

The standard integrated circuit technology has been developed to design and fabricate new innovative planar multi-junction solar cell chips for concentrated sunlight applications. This 1 cm x 1 cm cell consisted of several voltage generating regions called unit cells which were internally connected in series within a single chip resulting in high open circuit voltages. Typical open-circuit voltages of 3.6 V and short-circuit currents of 90 ma were obtained at 80 AM1 suns. A dramatic increase in both short circuit current and open circuit voltage with increased light levels was observed.

Valco, G. J.; Kapoor, V. J.; Evans, J. C.; Chai, A.-T.

1981-01-01

417

Oxide nanowires for solar cell applications  

NASA Astrophysics Data System (ADS)

Oxide nanowire arrays were studied for their applications to solar cells. It was demonstrated that the nanowires could provide direct pathways for electron transport in dye-sensitized solar cells and therefore, while forming photoelectrode films, they offered better suppression of charge recombination than nanoparticles. However, the photoelectron films consisting of nanowires suffered a disadvantage in giving large surface area for dye adsorption. Such a shortcoming of nanowires had been exemplified in this paper illustrating that it could be well compensated by incorporating with nanoparticles to form a nanoparticle-nanowire array hybrid photoelectrode film. The oxide nanowires were also demonstrated to be able to enhance the performance of inverted structure polymer solar cells as a cathode buffer layer by establishing a large interface with the polymers so as to facilitate the transport of photogenerated electrons from the polymer to the electron collecting electrode. Such an enhancement effect could be further boosted while the nanowires were replaced with nanotubes; the latter may build up larger interface with the polymers than the former and therefore facilitates the electron transport more efficiently.Oxide nanowire arrays were studied for their applications to solar cells. It was demonstrated that the nanowires could provide direct pathways for electron transport in dye-sensitized solar cells and therefore, while forming photoelectrode films, they offered better suppression of charge recombination than nanoparticles. However, the photoelectron films consisting of nanowires suffered a disadvantage in giving large surface area for dye adsorption. Such a shortcoming of nanowires had been exemplified in this paper illustrating that it could be well compensated by incorporating with nanoparticles to form a nanoparticle-nanowire array hybrid photoelectrode film. The oxide nanowires were also demonstrated to be able to enhance the performance of inverted structure polymer solar cells as a cathode buffer layer by establishing a large interface with the polymers so as to facilitate the transport of photogenerated electrons from the polymer to the electron collecting electrode. Such an enhancement effect could be further boosted while the nanowires were replaced with nanotubes; the latter may build up larger interface with the polymers than the former and therefore facilitates the electron transport more efficiently. This article was submitted as part of a collection highlighting papers on the `Recent Advances in Semiconductor Nanowires Research' from ICMAT 2011.

Zhang, Qifeng; Yodyingyong, Supan; Xi, Junting; Myers, Daniel; Cao, Guozhong

2012-02-01

418

Variation of solar cell sensitivity and solar radiation on tilted surfaces  

NASA Technical Reports Server (NTRS)

The validity is studied that one of various insolation models used to compute solar radiation incident on tilted surfaces from global data measured on horizontal surfaces. The variation of solar cell sensitivity to solar radiation is determined over a wide range of atmospheric condition. A new model was formulated that reduced the deviations between measured and predicted insolation to less than 3 percent. Evaluation of solar cell sensitivity data indicates small change (2-3 percent) in sensitivity from winter to summer for tilted cells. The feasibility of using such global data as a means for calibrating terrestrial solar cells is discussed.

Klucher, T. M.

1978-01-01

419

Gallium Arsenide solar cell radiation damage experiment  

NASA Technical Reports Server (NTRS)

Gallium arsenide (GaAs) solar cells for space applications from three different manufactures were irradiated with 10 MeV protons or 1 MeV electrons. The electrical performance of the cells was measured at several fluence levels and compared. Silicon cells were included for reference and comparison. All the GaAs cell types performed similarly throughout the testing and showed a 36 to 56 percent power areal density advantage over the silicon cells. Thinner (8-mil versus 12-mil) GaAs cells provide a significant weight reduction. The use of germanium (Ge) substrates to improve mechanical integrity can be implemented with little impact on end of life performance in a radiation environment.

Maurer, R. H.; Kinnison, J. D.; Herbert, G. A.; Meulenberg, A.

1991-01-01

420

Development of standardized specifications for silicon solar cells  

NASA Technical Reports Server (NTRS)

A space silicon solar cell assembly (cell and coverglass) specification aimed at standardizing the diverse requirements of current cell or assembly specifications was developed. This specification was designed to minimize both the procurement and manufacturing costs for space qualified silicon solar cell assembilies. In addition, an impact analysis estimating the technological and economic effects of employing a standardized space silicon solar cell assembly was performed.

Scott-Monck, J. A.

1977-01-01

421

Silicon solar cell process development, fabrication, and analysis  

NASA Technical Reports Server (NTRS)

Solar cells from HEM, Dendritic Webs, and EFG ribbons were fabricated and characterized. The HEM solar cells showed only slight enhancement in cell performance after gettering steps (diffusion glass) were added. Dendritic webs from various growth runs indicated that performance of solar cells made from the webs was not as good as that of the conventional CZ cells. The EFG ribbons grown in CO ambient showed significant improvement in silicon quality.

Yoo, H. I.; Iles, P. A.; Leung, D. C.

1980-01-01

422

Semi-transparent inverted organic solar cells  

NASA Astrophysics Data System (ADS)

We will present efficient semi-transparent bulk-heterojunction [regioregular of poly(3-hexylthiophene): (6,6)-phenyl C61 butyric acid methyl ester] solar cells with an inverted device architecture. Highly transparent ZnO and TiO2 films prepared by Atomic Layer Deposition are used as cathode interlayers on top of ITO. The topanode consists of a RF-sputtered ITO layer. To avoid damage due to the plasma deposition of this layer, a sputtering buffer layer of MoO3 is used as protection. This concept allows for devices with a transmissivity higher than 60 % for wavelengths 650 nm. The thickness of the MoO3 buffer has been varied in order to study its effect on the electrical properties of the solar cell and its ability to prevent possible damage to the organic active layers upon ITO deposition. Without this buffer or for thin buffers it has been found that device performance is very poor concerning the leakage current, the fill factor, the short circuit current and the power conversion efficiencies. As a reference inverted solar cells with a metal electrode (Al) instead of the ITO-top contact are used. The variation between the PCE of top versus conventional illumination of the semi-transparent cells was also examined and will be interpreted in view of the results of the optical simulation of the dielectric device stack with and without reflection top electrode. Power conversion efficiencies of 2-3 % for the opaque inverted solar cells and 1.5-2.5 % for the semi-transparent devices were obtained under an AM1.5G illumination.

Schmidt, H.; Winkler, T.; Tilgner, M.; Flügge, H.; Schmale, S.; Bülow, T.; Meyer, J.; Johannes, H.-H.; Riedl, T.; Kowalsky, W.

2009-08-01

423

Copper migration in cdte heterojunction solar cells  

NASA Astrophysics Data System (ADS)

CdTe solar cells were fabricated by depositing a Au/Cu contact with Cu thickness in the range of 50 to 150Å on polycrystalline CdTe/CdS/SnO2/glass structures. The increase in Cu thickness improves ohmic contact and reduces series resistance (Rs), but the excess Cu tends to diffuse into CdTe and lower shunt resistance (Rsh) and cell performance. Light I-V and secondary ion mass spectros-copy (SIMS) measurements were performed to understand the correlations between the Cu contact thickness, the extent of Cu incorporation in the CdTe cells, and its impact on the cell performance. The CdTe/CdS/SnO2/glass, CdTe/ CdS/GaAs, and CdTe/GaAs structures were prepared in an attempt to achieve CdTe films with different degrees of crystallinity and grain size. A large grain polycrystalline CdTe thin film solar cell was obtained for the first time by selective etching the GaAs substrate coupled with the film transfer onto a glass substrate. SIMS measurement showed that poor crystallinity and smaller grain size of the CdTe film promotes Cu diffusion and decreases the cell performance. Therefore, grain boundaries are the main conduits for Cu migration and larger CdTe grain size or alternate method of contact formation can mitigate the adverse effect of Cu and improve the cell performance.

Chou, H. C.; Rohatgi, A.; Jokerst, N. M.; Thomas, E. W.; Kamra, S.

1996-07-01

424

Multiple-gap amorphous solar cells reconsidered  

NASA Astrophysics Data System (ADS)

The effect of irradiation conditions on the conversion efficiency of amorphous solar cells is investigated using numerical simulations based on published performance data. A single-gap cell (with gap 1.5 eV) a two-gap cell (1.85 and 1.35 eV) and a three-gap cell (2.0, 1.7, and 1.45 eV) are evaluated for Am1, AM1.5, AM2, and AM4 standard spectra at different irradiance levels, and for the spectra and irradiances measured at 53 deg N by Munroe and Shepherd (1981). The results are presented in tables and graphs and discussed. It is found that solar cells should be optimized for long-term energy output under the range of atmospheric conditions and sun-position variations of the proposed site rather than for one set of idealized conditions. Under this procedure, the single-condition benefits of multiple-gap cells are lost, so that their use is indicated only for space applications. The optimum single-gap-cell bandgap is also shown to be depend on the site characteristics.

Chambouleyron, I.

1984-09-01

425

Recent advances in sensitized mesoscopic solar cells.  

PubMed

Perhaps the largest challenge for our global society is to find ways to replace the slowly but inevitably vanishing fossil fuel supplies by renewable resources and, at the same time, avoid negative effects from the current energy system on climate, environment, and health. The quality of human life to a large degree depends upon the availability of clean energy sources. The worldwide power consumption is expected to double in the next 3 decades because of the increase in world population and the rising demand of energy in the developing countries. This implies enhanced depletion of fossil fuel reserves, leading to further aggravation of the environmental pollution. As a consequence of dwindling resources, a huge power supply gap of 14 terawatts is expected to open up by year 2050 equaling today's entire consumption, thus threatening to create a planetary emergency of gigantic dimensions. Solar energy is expected to play a crucial role as a future energy source. The sun provides about 120,000 terawatts to the earth's surface, which amounts to 6000 times the present rate of the world's energy consumption. However, capturing solar energy and converting it to electricity or chemical fuels, such as hydrogen, at low cost and using abundantly available raw materials remains a huge challenge. Chemistry is expected to make pivotal contributions to identify environmentally friendly solutions to this energy problem. One area of great promise is that of solar converters generally referred to as "organic photovoltaic cells" (OPV) that employ organic constituents for light harvesting or charge carrier transport. While this field is still in its infancy, it is receiving enormous research attention, with the number of publications growing exponentially over the past decade. The advantage of this new generation of solar cells is that they can be produced at low cost, i.e., potentially less than 1 U.S. $/peak watt. Some but not all OPV embodiments can avoid the expensive and energy-intensive high vacuum and materials purification steps that are currently employed in the fabrication of all other thin-film solar cells. Organic materials are abundantly available, so that the technology can be scaled up to the terawatt scale without running into feedstock supply problems. This gives organic-based solar cells an advantage over the two major competing thin-film photovoltaic devices, i.e., CdTe and CuIn(As)Se, which use highly toxic materials of low natural abundance. However, a drawback of the current embodiment of OPV cells is that their efficiency is significantly lower than that for single and multicrystalline silicon as well as CdTe and CuIn(As)Se cells. Also, polymer-based OPV cells are very sensitive to water and oxygen and, hence, need to be carefully sealed to avoid rapid degradation. The research discussed within the framework of this Account aims at identifying and providing solutions to the efficiency problems that the OPV field is still facing. The discussion focuses on mesoscopic solar cells, in particular, dye-sensitized solar cells (DSCs), which have been developed in our laboratory and remain the focus of our investigations. The efficiency problem is being tackled using molecular science and nanotechnology. The sensitizer constitutes the heart of the DSC, using sunlight to pump electrons from a lower to a higher energy level, generating in this fashion an electric potential difference, which can exploited to produce electric work. Currently, there is a quest for sensitizers that achieve effective harnessing of the red and near-IR part of sunlight, converting these photons to electricity better than the currently used generation of dyes. Progress in this area has been significant over the past few years, resulting in a boost in the conversion efficiency of the DSC that will be reviewed. PMID:19715294

Grätzel, Michael

2009-11-17

426

I-V Characterization of Solar Cells Caracterizacao I-V de Celulas Solares.  

National Technical Information Service (NTIS)

Equivalent circuits were analysed and then I-V characteristics obtained from different solar cells were compared with those from the circuits. The measures were obtained under natural conditions and under artificial conditions (solar simulator made of eas...

N. Veissid R. Ranvaud F. J. Fonseca

1981-01-01

427

An efficient power electronics solution for lateral multi-junction solar cell systems  

Microsoft Academic Search

Compared to a single junction solar cell, a multi-junction (MJ) solar cell can extract higher energy from sun by splitting the solar spectrum. Depending on the spectrum splitting techniques, two different structures of MJ solar cells are possible: vertical multijunction solar cell (VMJ) and lateral multijunction solar cell (LMJ). Both of these structures have their own advantages and limitations. LMJ

Mohammed Khorshed Alam; Faisal H. Khan; Abu Saleh Imtiaz

2011-01-01

428

Laser sintering of photoelectrode layers for Dye Solar Cell technology  

Microsoft Academic Search

Scanning laser processing has become a useful and often used tool in thin film solar cell industries, since it enables precise, low cost, non-contact and highly automated fabrication processes such as scribing, patterning, marking, edge deletion, local melting and sintering. Dye solar cells (DSCs) are electrochemical photovoltaic devices representing an attractive technology for large area solar energy conversion since they

G. Mincuzzi; L. Vesce; R. Riccitelli; A. Reale; A. Di Carlo; T. M. Brown

2009-01-01

429

High performance organic solar cells with interface engineering  

Microsoft Academic Search

Polymer solar cells are considered a promising candidate for renewable energy with low-cost and high volume production capability. The main focus of this dissertation is to investigate the several approaches for improving the efficiency of polymer solar cells. These approaches include understanding of the physics, operation mechanisms, materials and device engineering and optimization of fabrication processes. A typical polymer solar

Mi Hyae Park

2010-01-01

430

Controlled power interface between solar cells and AC source  

Microsoft Academic Search

A novel interface circuit between solar cells and a commercial AC source using Van Allen's multivibrator is presented. In this circuit, the AC source is used as a backup for solar cells, and the source and load power flow is automatically balanced by the circuit itself without any external phase control. Based on the analysis of the characteristics of solar

Koosuke Harada; Gen Zhao

1993-01-01

431

High-Efficiency Solar Cell Concepts: Physics, Materials, and Devices  

Microsoft Academic Search

Over the past three decades, significant progress has been made in the area of high-efficiency multijunction solar cells, with the effort primarily directed at current-matched solar cells in tandem. The key materials issues here have been obtaining semiconductors with the required bandgaps for sequential absorption of light in the solar spectrum and that are lattice matched to readily available substrates.

A. Mascarenhas; S. Francoeur; M. J. Seong; B. Fluegel; Y. Zhang; M. W. Wanlass

2005-01-01

432

Solar cells: Operating principles, technology, and system applications  

Microsoft Academic Search

Solar cell theory, materials, fabrication, design, modules, and systems are discussed. The solar source of light energy is described and quantified, along with a review of semiconductor properties and the generation, recombination, and the basic equations of photovoltaic device physics. Particular attention is given to p-n junction diodes, including efficiency limits, losses, and measurements. Si solar cell technology is described

M. A. Green

1982-01-01

433

Nanostructured upconverters for improved solar cell performance  

NASA Astrophysics Data System (ADS)

Triplet-triplet annihilation photon upconversion (TTA-UC) is a promising candidate for mitigating sub-band gap absorption losses in solar cells. In TTA-UC, sensitiser dyes absorb sub-band gap photons, cross to a triplet state, and transfer triplet excitons to emitter dyes. Two triplet-excited emitters can undergo TTA, raising one emitter to a higher-energy bright singlet state. The quadratic efficiency of TTA-UC at device-relevant light intensities motivates a push towards the higher chromophore densities achievable in the solid phase. We have begun this process by tethering tetrakisquinoxalino palladium porphyrin to 20nm silica nanoparticles using peptide chemistry techniques, achieving a total-volume concentration of 1.5mM. The phosphorescence kinetics of the tethered porphyrins was measured to quantify quenching by rubrene emitter. Upconverter performance was measured in a solar cell enhancement experiment.

MacQueen, Rowan W.; Schulze, Tim F.; Khoury, Tony; Cheng, Yuen Yap; Stannowski, Bernd; Lips, Klaus; Crossley, Maxwel J.; Schmidt, Timothy

2013-09-01

434

Advanced Solar Cell Testing and Characterization  

NASA Technical Reports Server (NTRS)

The topic for this workshop stems from an ongoing effort by the photovoltaic community and U.S. government to address issues and recent problems associated with solar cells and arrays experienced by a number of different space systems. In April 2003, a workshop session was held at the Aerospace Space Power Workshop to discuss an effort by the Air Force to update and standardize solar cell and array qualification test procedures in an effort to ameliorate some of these problems. The organizers of that workshop session thought it was important to continue these discussions and present this information to the entire photovoltaic community. Thus, it was decided to include this topic as a workshop at the following SPRAT conference.

Bailey, Sheila; Curtis, Henry; Piszczor, Michael

2005-01-01

435

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 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 elecrically 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, G.

1982-06-21

436

Will Organic Synthesis Within Icy Grains or on Dust Surfaces in the Primitive Solar Nebula Completely Erase the Effects of Photochemical Self Shielding?  

NASA Technical Reports Server (NTRS)

There are at least 3 separate photochemical self-shielding models with different degrees of commonality. All of these models rely on the selective absorption of (12))C(16)O dissociative photons as the radiation source penetrates through the gas allowing the production of reactive O-17 and O-18 atoms within a specific volume. Each model also assumes that the undissociated C(16)O is stable and does not participate in the chemistry of nebular dust grains. In what follows we will argue that this last, very important assumption is simply not true despite the very high energy of the CO molecular bond.

Nuth, Joseph A., III; Johnson, Natasha M.

2012-01-01

437

Solar-QBO interaction and its impact on stratospheric ozone in a zonally averaged photochemical transport model of the middle atmosphere  

Microsoft Academic Search

We investigate the solar cycle modulation of the quasi-biennial oscillation (QBO) in stratospheric zonal winds and its impact on stratospheric ozone with an updated version of the zonally averaged CHEM2D middle atmosphere model. We find that the duration of the westerly QBO phase at solar maximum is 3 months shorter than at solar minimum, a more robust result than in

J. P. McCormack; D. E. Siskind; L. L. Hood

2007-01-01

438

Inverted colloidal quantum dot solar cells.  

PubMed

An inverted architecture of quantum dot solar cells is demonstrated by introducing a novel ZnO method on top of the PbS CQD film. Improvements in device characteristics stem from constructive optical interference from the ZnO layer that enhances absorption in the PbS CQD layer. Outstanding diode characteristics arising from a superior PbS/ZnO junction provide a further electronic advantage. PMID:24677118

Kim, Gi-Hwan; Walker, Bright; Kim, Hak-Beom; Kim, Jin Young; Sargent, Edward H; Park, Jongnam; Kim, Jin Young

2014-05-01

439

Heterojunction solar cells on cuprous oxide  

Microsoft Academic Search

Heterojunction solar cells were made on Cu2O by sputtering In2O3, SnO2, CdO and mixtures of CdO and SnO2 and by thermal evaporation of ZnSe. Photovoltaic effects were observed in most cases. High series resistances were an indication of chemical reactions at the interface. Auger surface analysis showed evidence of copper metal at the interface, arising from chemical reactions. For a

L. Papadimitriou; N. A. Economou; D. Trivich

1981-01-01

440

Solar cell array with lightweight support structure  

Microsoft Academic Search

A panel comprising an aluminum honeycomb core and outer face skins of Kevlar, a bi-directional epoxy-reinforced polyparabenzamide fabric which is a thermal and electrical insulator adhering to the core and forming the opposite flat surfaces of the panel. Solar cells are glued directly to one face skin while a set of epoxy-reinforced carbon fiber stiffeners are glued to the other

Gounder

1983-01-01

441

Low cost ITO silicon solar cells  

Microsoft Academic Search

Heterojunction solar cells consisting of chemically sprayed indium-tin-oxide (ITO) deposited on the n-type single crystal Si wafers were investigated. Ni was deposited on the back of the device by the electroless method and grid type front contact was used by evaporating Ag onto ITO. For a 50,000 lx white light of a tungsten lamp, an open circuit voltage of 0.221

A. Raza; B. K. Gupta; O. P. Agnihotri; S. S. Mathur

1979-01-01

442

Reversible photovoltaic-electrochemical solar cell  

Microsoft Academic Search

The development of a novel solar electrochemical rechargeable battery is reported. The device uses n-BaTiO3 as photo-anode for charging by sunlight, and Pt electrodes for the dark, reverse reaction. The electrolyte is Ce(3+)\\/Ce(4+) solution, which behaves like a cathode during charging. The cell has a potential of 0.62 V and a current on the order of 0.20 mA\\/sq cm. The

M. Sharon; A. Sinha

1981-01-01

443

Solid state dye solar cell modules  

NASA Astrophysics Data System (ADS)

We fabricated the first solid state dye solar cell (SDSC) module using poly(3-hexilthiophene) (P3HT) as Hole Transport Material for the dye regeneration process. Integrated interconnections were obtained following the "Monolithic" architecture for series connections. The fabricated SDSC module has a conversion efficiency of 2.0% on active area. These results represent a promising starting point for an effective up-scaling of SDSC devices.

Matteocci, F.; Casaluci, S.; Razza, S.; Guidobaldi, A.; Brown, T. M.; Reale, A.; Di Carlo, A.

444

High efficiency silicon solar cell review  

NASA Technical Reports Server (NTRS)

An overview is presented of the current research and development efforts to improve the performance of the silicon solar cell. The 24 papers presented reviewed experimental and analytic modeling work which emphasizes the improvment of conversion efficiency and the reduction of manufacturing costs. A summary is given of the round-table discussion, in which the near- and far-term directions of future efficiency improvements were discussed.

Godlewski, M. P. (editor)

1975-01-01

445

Recombination saturation effects in silicon solar cells  

Microsoft Academic Search

Significant interest has recently been shown in the use of dark and illuminated current-voltage (I-V) measurements for the characterization of high-efficiency silicon solar cells. Similar nonideal behavior, in the form of “humps” in dark I-V curves, has been observed by various research groups but apparently different interpretations of this effect given. In this paper we present detailed computer simulations of

Stephen J. Robinson; Armin G. Aberle; Martin A. Green

1994-01-01

446

Chalcopyrite thin film solar cells by electrodeposition  

Microsoft Academic Search

This paper reviews the state of the art in using electrodeposition to prepare chalcopyrite absorber layers in thin film solar cells. Most of the studies deal with the direct preparation of Cu(In,Ga)Se2 films, and show that the introduction of gallium in the films is now becoming possible from single bath containing all the elements. Electrodeposition can also be used to

D. Lincot; J. F. Guillemoles; S. Taunier; D. Guimard; J. Sicx-Kurdi; A. Chaumont; O. Roussel; O. Ramdani; C. Hubert; J. P. Fauvarque; N. Bodereau; L. Parissi; P. Panheleux; P. Fanouillere; N. Naghavi; P. P. Grand; M. Benfarah; P. Mogensen; O. Kerrec

2004-01-01

447

Cadmium telluride films and solar cells  

Microsoft Academic Search

CdTe thin films for solar cell applications have been deposited by close-spaced vapor transport and by hot-wall vacuum evaporation. As-deposited films are p-type with hole densities that increase to values of 1 X 10¹⁶ cm⁻³ with increasing substrate temperature. A variety of experimental results can be interpreted either in terms of doping by native defects such as cadmium vacancies or

R. H. Bube; A. L. Fahrenbruch; R. Sinclair; T. C. Anthony; C. Fortmann; W. Huber; Chun-Teh Lee; T. Thorpe; T. Yamashita

1984-01-01

448

Radiation effects on thin film solar cells  

Microsoft Academic Search

A study has been undertaken to assess the effects of 1 MeV electron radiation on two types of thin film solar cells, thin-film silicon:hydrogen alloy (TFS) and copper indium diselenide (CIS). Using TFS devices with efficiencies between 8-9% AM 0 (9-10% AM 1.5), and CIS devices with efficiencies between 7-8% AM 0 (8-9% AM 1.5), the results show the devices

C. F. Gay; B. E. Anspaugh; R. R. Potter; D. P. Tanner

1984-01-01

449

Towards high efficiency polycrystalline silicon solar cells  

Microsoft Academic Search

Trends in progress towards high efficiency polycrystalline solar cells are assessed. Research is concentrated on minimizing recombination losses within grains, at the grain boundaries and at the surface. Reductions in the minority carrier diffusion length, obtaining a substrate resistivity of 0.2-0.4 ohm-cm and devising ribbon growth techniques that control grain dislocation defects are still development goals. Ribbons have thus far

B. L. Sopori; R. A. Pryor

1984-01-01

450

Thin monocrystalline silicon films for solar cells  

Microsoft Academic Search

Thin film monocrystalline silicon solar cells based on porous silicon layer transfer processes could be cost-effective because of their lower consumption of material use and the potential for high efficiency. Novel techniques of porous silicon film separation, obtained by anodization of silicon, are presented. Anodization techniques for porous silicon film separation are classified as either one-step or two-step. Two-step anodization

C. S. Solanki; R. R. Bilyalov; G. Beaucarne; J. Poortmans

2003-01-01

451

Organic p -i- n solar cells  

Microsoft Academic Search

We introduce a p-i- n-type heterojunction architecture for organic solar cells where the active region is sandwiched between two doped wide-gap layers. The term p-i- n means here a layer sequence in the form p-doped layer, intrinsic layer and n-doped layer. The doping is realized by controlled co-evaporation using organic dopants and leads to conductivities of 10 -4 to 10

B. Maennig; J. Drechsel; D. Gebeyehu; P. Simon; F. Kozlowski; A. Werner; F. Li; S. Grundmann; S. Sonntag; M. Koch; K. Leo; M. Pfeiffer; H. Hoppe; D. Meissner; N. S. Sariciftci; I. Riedel; V. Dyakonov; J. Parisi

2004-01-01

452

New high-efficiency silicon solar cells  

NASA Technical Reports Server (NTRS)

A design for silicon solar cells was investigated as an approach to increasing the cell open-circuit voltage and efficiency for flat-plate terrestrial photovoltaic applications. This deviates from past designs, where either the entire front surface of the cell is covered by a planar junction or the surface is textured before junction formation, which results in an even greater (up to 70%) junction area. The heavily doped front region and the junction space charge region are potential areas of high recombination for generated and injected minority carriers. The design presented reduces junction area by spreading equidiameter dot junctions across the surface of the cell, spaced about a diffusion length or less from each other. Various dot diameters and spacings allowed variations in total junction area. A simplified analysis was done to obtain a first-order design optimization. Efficiencies of up to 19% can be obtained. Cell fabrication involved extra masking steps for selective junction diffusion, and made surface passivation a key element in obtaining good collection. It also involved photolithography, with line widths down to microns. A method is demonstrated for achieving potentially high open-circuit voltages and solar-cell efficiencies.

Daud, T.; Crotty, G. T.

1985-01-01

453

Conductor-insulator-semiconductor organic solar cells  

NASA Astrophysics Data System (ADS)

A new class of conductor-insulator-semiconductor (CIS) organic solar cells has been developed, whose novel features include the application of a transparent, conductive front electrode and a thin insulating layer. The selection of the front electrode divides CIS organic cells into three configurations: (1) a metal-insulator-semiconductor cell having a metal front electrode; (2) a semiconductor-insulator-semiconductor cell having a degenerate semiconductor electrode; and (3) an electrolyte-insulator-semiconductor cell using electrolytic contact. The barrier formation in the base organic semiconductor is determined by the work function of the transparent conductive electrode. The material used in the present study for the base semiconducting layer is an X-phase, metal-free phthalocyanine-polymer binder combination which can be deposited onto a substrate by solution casting.

Loutfy, R. O.; Shing, Y.-H.; Murti, D. K.

1982-04-01

454

Gallium arsenide solar cell radiation damage study  

NASA Technical Reports Server (NTRS)

A thorough analysis has been made of electron- and proton- damaged GaAs solar cells suitable for use in space. It is found that, although some electrical parametric data and spectral response data are quite similar, the type of damage due to the two types of radiation is different. An I-V analysis model shows that electrons damage the bulk of the cell and its currents relatively more, while protons damage the junction of the cell and its voltages more. It is suggested that multiple defects due to protons in a strong field region such as a p/n junction cause the greater degradation in cell voltage, whereas the individual point defects in the quasi-neutral minority-carrier-diffusion regions due to electrons cause the greater degradation in cell current and spectral response.

Maurer, R. H.; Herbert, G. A.; Kinnison, J. D.; Meulenberg, A.

1989-01-01

455

Hairlike Percutaneous Photochemical Sensors  

NASA Technical Reports Server (NTRS)

Instrumentation systems based on hairlike fiber-optic photochemical sensors have been proposed as minimally invasive means of detecting biochemicals associated with cancer and other diseases. The fiber-optic sensors could be mass-produced as inexpensive, disposable components. The sensory tip of a fiber-optic sensor would be injected through the patient's skin into subcutaneous tissue. A biosensing material on the sensory tip would bind or otherwise react with the biochemical(s) of interest [the analyte(s)] to produce a change in optical properties that would be measured by use of an external photonic analyzer. After use, a fiber-optic sensor could be simply removed by plucking it out with tweezers. A fiber-optic sensor according to the proposal would be of the approximate size and shape of a human hair, and its sensory tip would resemble a follicle. Once inserted into a patient's subcutaneous tissue, the sensor would even more closely resemble a hair growing from a follicle (see Figure 1). The biosensing material on the sensory tip could consist of a chemical and/or cells cultured and modified for the purpose. The biosensing material would be contained within a membrane that would cover the tip. If the membrane were not permeable by an analyte, then it would be necessary to create pores in the membrane that would be large enough to allow analyte molecules to diffuse to the biosensing material, but not so large as to allow cells (if present as part of the biosensing material) to diffuse out. The end of the fiber-optic sensor opposite the sensory tip would be inserted in a fiberoptic socket in the photonic analyzer.

George, Thomas; Loeb, Gerald

2004-01-01

456

Device simulation of intermediate band solar cells  

NASA Astrophysics Data System (ADS)

To realize high efficiency solar cells, new concepts beyond the Shockley-Queisser limit are widely investigated. The intermediate band solar cell (IBSC) is one of the candidate concepts. From the importance of device physics, we have developed a device simulator for IBSCs. For device simulation of IBSC, the Poisson equation, carrier continuity equations of electrons in the conduction band (CB) and the valance band (VB) and balanced equation of IB state electrons must be solved self-consistently. The simulation methods can clarify the intrinsic device behavior of IBSCs which cannot be investigated by the detailed balance model. For example, by the existence of electrons trapped in IB states, electrostatic potential along the depth direction of the solar cells is strongly modified from the equilibrium under illumination of sunlight. This potential change is strongly related to its absorption property of sunlight. And the doping to IB region can enhance short circuit current density via IB states. Under larger concentration, this doping effect is decreased by the photofilling effects in the radiative limit. Absorption coefficients of each band-to-band transition are decided by the semiconductor materials and fundamental physics. These limitations make the different spectra and values from ideal treatments and decide the maximum efficiency of the IBSC. In this work, we present the fundamental properties and suggestions to approach the high efficiency IBSC operations as a device.

Yoshida, K.; Okada, Y.; Sano, N.

2012-02-01

457

Machine vision for solar cell characterization  

NASA Astrophysics Data System (ADS)

An in-line, non-destructive process is being developed for characterizing polycrystalline thin-film and other large area electronic devices using computer vision based imaging of the manufacturing and inspection steps during the device fabrication process. This process is being applied specifically to Cadmium Telluride/Cadmium Sulfide (CdTe/CdS) thin film, polycrystalline solar cells. Our process involves the acquisition of reflective, transmission and electroluminescence (EL) intensity images for each device. The EL intensity images have been processed by use of a modified median cut segmentation. The processed images reveal different gray level regions corresponding to different intensities of EL originating from radiative recombination events occurring within a biased solar cell. Higher efficiency devices show a more uniform intensity distribution in contrast with lower efficiency devices. The uniform intensity regions are made up of gray level intensity values found near the mean of the histogram distribution these are identified as regions of good device performance and are attributed to better material quality and processing. Low intensity regions indicate either material defects or errors in processing. This novel characterization process and analysis are providing new insights into the causes of poor performance in CdTe-based solar cells.

Ordaz, Miguel A.; Lush, Gregory B.

2000-03-01

458

US polycrystalline thin film solar cells program  

SciTech Connect

The Polycrystalline Thin Film Solar Cells Program, part of the United States National Photovoltaic Program, performs R D on copper indium diselenide and cadmium telluride thin films. The objective of the Program is to support research to develop cells and modules that meet the US Department of Energy's long-term goals by achieving high efficiencies (15%-20%), low-cost ($50/m{sup 2}), and long-time reliability (30 years). The importance of work in this area is due to the fact that the polycrystalline thin-film CuInSe{sub 2} and CdTe solar cells and modules have made rapid advances. They have become the leading thin films for PV in terms of efficiency and stability. The US Department of Energy has increased its funding through an initiative through the Solar Energy Research Institute in CuInSe{sub 2} and CdTe with subcontracts to start in Spring 1990. 23 refs., 5 figs.

Ullal, H.S.; Zweibel, K.; Mitchell, R.L. (Solar Energy Research Inst., Golden, CO (USA)) [Solar Energy Research Inst., Golden, CO (USA)

1989-11-01

459

Alloys in cadmium telluride solar cells  

NASA Astrophysics Data System (ADS)

Alloys formed intentionally or unintentionally during the fabrication of CdTe/CdS solar cells were investigated. The primary focuses were (1) characterizing thin films of CdTesb{1-x}Ssb{x} since these alloys appear to be present in all high-efficiency CdTe/CdS solar cells, and (2) investigating how these alloys affect solar cell performance. Thin films of CdTesb{1-x}Ssb{x} were fabricated and subjected to heat treatments under conditions identical to those used for making CdTe/CdS solar cells. The films were characterized by X-Ray Diffraction, Energy Dispersive Spectroscopy, Scanning Electron Microscopy, and optical measurements. The as-deposited CdTesb{1-x}Ssb{x} films were generally single-phase even when x was well within the miscibility gap shown on CdTe-CdS pseudo-binary phase diagrams. Heat treatments at 415sp°C in the presence of CdClsb2 promoted phase segregation. From diffraction analysis of the phase-segregated films, the solubility limits at 415sp°C of CdS in CdTe, and of CdTe in CdS were found to be 5.8± 0.2% and 3± 1%, respectively. Conventional CdTe/CdS solar cells and novel solar cells made by depositing CdTesb{1-x}Ssb{x}, in place of CdTe were fabricated, tested, characterized, and compared. For the conventional solar cells, diffusion of CdS into the CdTe layer during the fabrication process converted the CdTe to CdTesb{1-x}Ssb{x} with x ranging from the 5.8% solubility limit near the junction to {<}1% near the back contact. Similarly, the CdS layer was converted to CdSsb{1-y}Tesb{y} with y near the 3% solubility limit, in some cases, and {<}1% in cases where the CdS film was annealed with CdClsb2 prior to depositing CdTe. The performance of CdTesb{1-x}Ssb{x}/CdS cells made with x = 0.05-0.06 throughout the absorber layer was nearly identical to the CdTe/CdS cells. This indicates that the operation of conventional devices is largely controlled by the alloys formed by interdiffusion. For the CdTesb{1-x}Ssb{x}/CdS devices, less CdS was consumed by the interdiffusion process than for the conventional CdTe/CdS devices suggesting that devices can be made using thinner CdS layers than before possible without pinholes forming in the CdS.

Jensen, Douglas Garth

460

Measurement and Characterization of Concentrator Solar Cells II  

NASA Technical Reports Server (NTRS)

Concentrator solar cells are continuing to get more consideration for use in power systems. This interest is because concentrator systems can have a net lower cost per watt in solar cell materials plus ongoing improvements in sun-tracking technology. Quantitatively measuring the efficiency of solar cells under concentration is difficult. Traditionally, the light concentration on solar cells has been determined by using a ratio of the measured solar cell s short circuit current to that at one sun, this assumes that current changes proportionally with light intensity. This works well with low to moderate (<20 suns) concentration levels on "well-behaved" linear cells but does not apply when cells respond superlinearly, current increases faster than intensity, or sublinearly, current increases more slowly than intensity. This paper continues work on using view factors to determine the concentration level and linearity of the solar cell with mathematical view factor analysis and experimental results [1].

Scheiman, Dave; Sater, Bernard L.; Chubb, Donald; Jenkins, Phillip; Snyder, Dave

2005-01-01

461

MANUFACTURE OF PHOTOVOLTAIC SOLAR CELL USING PLANT CHLOROPHYLL  

EPA Science Inventory

To date, we have successfully manufactured working chlorophyll sensitized solar cells using chlorophyll (and b mixture) from spinach leaves. We have evaluated the electronic characteristics (voltage, current, and power outputs using different loading resistors) of this solar c...

462

Research Profiling: Nano-enhanced, Thin-film Solar Cells  

Microsoft Academic Search

Nanotechnology-enhanced thin-film solar cells constitute one of the most promising solar energy solutions and an important currently emerging application of nanotechnology. This paper profiles the research patterns via \\

Ying Guo; Lu Huang; Alan L. Porter

463

Hydrogen-Impregnated Glass Covers for Hardened Solar Cells.  

National Technical Information Service (NTIS)

The report summarizes the entire development program conducted by Tem-Pres Research/Carborundum which experimentally demonstrated that hydrogen impregnation will significantly reduce darkening of solar cell glass covers under solar, nuclear, and van Allen...

S. P. Faile W. R. Harding

1970-01-01

464

Advantages of Sun tracking for planar silicon solar cells  

Microsoft Academic Search

Experimental results comparing the power output of a Sun tracking solar cell with that of a stationary solar cell indicates that the tracking cell will produce over 30% more electrical energy in the course of a relatively clear day than will the stationary cell. A mathematical treatment of the problem agrees remarkably well with the experimental results predicting only slightly

D. M. Mosher; R. E. Boese; R. J. Soukup

1977-01-01

465

Photocurrent images of amorphous-silicon solar-cell modules  

NASA Technical Reports Server (NTRS)

Results obtained in applying the unique characteristics of the solar cell laser scanner to investigate the defects and quality of amorphous silicon cells are presented. It is concluded that solar cell laser scanners can be effectively used to nondestructively test not only active defects but also the cell quality and integrity of electrical contacts.

Kim, Q.; Shumka, A.; Trask, J.

1985-01-01

466

Triple Junction Polymer Solar Cells for Photoelectrochemical Water Splitting.  

PubMed

A triple junction polymer solar cell in a novel 1 + 2 type configuration provides photoelectrochemical water splitting in its maximum power point at V ? 1.70 V with an estimated solar to hydrogen energy conversion efficiency of 3.1%. The triple junction cell consists of a wide bandgap front cell and two identical small bandgap middle and back cells. PMID:23625814

Esiner, Serkan; van Eersel, Harm; Wienk, Martijn M; Janssen, René A J

2013-04-26

467

Inversion layer solar cell fabrication and evaluation  

NASA Technical Reports Server (NTRS)

Inversion layer solar cells have been fabricated by etching through the diffused layer on p-type silicon wafers in a comb-like contact pattern. The charge separation comes from an induced p-n junction at the surface. This inverted surface is caused by a layer of transparent material applied to the surface that either contains free positive ions or that creates donor states at the interface. Cells have increased from 3 ma Isc to 100 ma by application of sodium silicate. The action is unstable, however, and decays with time.

Call, R. L.

1974-01-01

468

High-intensity, solid-state-solar cell device  

Microsoft Academic Search

A semiconductor solar cell capable of converting incident radiation to electrical energy at high efficiency includes a plurality of series-connected unit solar cells formed on a common wafer of semiconductor material. The unit solar cells each include a semiconductor substrate of one conductivity type and a p-n junction formed in the substrate. The light-receiving surface of the cell may have

R. I. Frank; R. Kaplow

1980-01-01

469

High-intensity, solid-state-solar cell device  

Microsoft Academic Search

A semiconductor solar cell capable of converting incident radiation to electrical energy at high efficiency includes a plurality of series-connected unit solar cells formed on a common wafer of semiconductor material. The unit solar cells each include a semiconductor substrate of one conductivity type and a p-n junction formed in the substrate. The light-receiving surface of the cell may have

R. Kaplow; R. I. Frank

1978-01-01

470

New trends in thin-film silicon solar cell technology  

Microsoft Academic Search

Thin-film silicon solar cell technology based on hydrogenated amorphous silicon has matured over the last two decades and is capable of delivering commercial modules with almost 10% stabilized efficiency. The status of thin-film silicon cell technology is reviewed by comparing it to other major solar cell technologies. The basic operation principles and the shortcomings of a-Si:H solar cells are outlined.

M. Zeman

2002-01-01

471

Transparent antennas for solar cell integration  

NASA Astrophysics Data System (ADS)

Transparent patch antennas are microstrip patch antennas that have a certain level of optical transparency. Highly transparent patch antennas are potentially suitable for integration with solar panels of small satellites, which are becoming increasingly important in space exploration. Traditional patch antennas employed on small satellites compete with solar cells for surface area. However, a transparent patch antenna can be placed directly on top of solar cells and resolve the issue of competing for limited surface real estate. For such an integration, a high optical transparency of the patch antenna is required from the solar cells' point of view. On the other hand, the antenna should possess at least acceptable radiation properties at the same time. This dissertation focuses on some of the most important concerns from the perspective of small satellite applications. For example, an optimization method to simultaneously improve both optical transparency and radiation efficiency of the antenna is studied. Active integrated antenna design method is extended to meshed patch applications in an attempt to improve the overall power efficiency of the front end communication subsystem. As is well known, circular polarization is immune from Faraday rotation effect in the ionosphere and thus can avoid a 3-dB loss in geo-satellite communication. Therefore, this research also aims to present design methods for circularly polarized meshed patch antennas. Moreover, a meshed patch antenna capable of supporting a high communication data rate is investigated. Lastly, other types of transparent patch antennas are also analyzed and compared to meshed patches. In summary, many properties of transparent patch antennas are examined in order to meet different design requirements.

Yasin, Tursunjan

472

Materials That Enhance Efficiency and Radiation Resistance of Solar Cells  

NASA Technical Reports Server (NTRS)

A thin layer (approximately 10 microns) of a novel "transparent" fluorescent material is applied to existing solar cells or modules to effectively block and convert UV light, or other lower solar response waveband of solar radiation, to visible or IR light that can be more efficiently used by solar cells for additional photocurrent. Meanwhile, the layer of fluorescent coating material remains fully "transparent" to the visible and IR waveband of solar radiation, resulting in a net gain of solar cell efficiency. This innovation alters the effective solar spectral power distribution to which an existing cell gets exposed, and matches the maximum photovoltaic (PV) response of existing cells. By shifting a low PV response waveband (e.g., UV) of solar radiation to a high PV response waveband (e.g. Vis-Near IR) with novel fluorescent materials that are transparent to other solar-cell sensitive wavebands, electrical output from solar cells will be enhanced. This approach enhances the efficiency of solar cells by converting UV and high-energy particles in space that would otherwise be wasted to visible/IR light. This innovation is a generic technique that can be readily implemented to significantly increase efficiencies of both space and terrestrial solar cells, without incurring much cost, thus bringing a broad base of economical, social, and environmental benefits. The key to this approach is that the "fluorescent" material must be very efficient, and cannot block or attenuate the "desirable" and unconverted" waveband of solar radiation (e.g. Vis-NIR) from reaching the cells. Some nano-phosphors and novel organometallic complex materials have been identified that enhance the energy efficiency on some state-of-the-art commercial silicon and thin-film-based solar cells by over 6%.

Sun, Xiadong; Wang, Haorong

2012-01-01

473

Research in Photochemical Energy Conversion.  

National Technical Information Service (NTIS)

The results of investigations dealing with the following topics in photochemical energy conversion are presented: Apparatus for Photochemical Studies; Studies of Charge Transfer Systems; The Photochemistry of Perinaphthenone; The Photoreduction of Phenant...

K. Weiss

1971-01-01

474

A theoretical analysis of the current-voltage characteristics of solar cells  

NASA Technical Reports Server (NTRS)

The following topics are discussed: (1) dark current-voltage characteristics of solar cells; (2) high efficiency silicon solar cells; (3) short circuit current density as a function of temperature and the radiation intensity; (4) Keldysh-Franz effects and silicon solar cells; (5) thin silicon solar cells; (6) optimum solar cell designs for concentrated sunlight; (7) nonuniform illumination effects of a solar cell; and (8) high-low junction emitter solar cells.

Fang, R. C. Y.; Hauser, J. R.

1979-01-01

475

Correcting For Capacitance In Tests Of Solar Cells  

NASA Technical Reports Server (NTRS)

Modified procedure for testing solar photovoltaic cells and modified software for processing test data provide corrections for effects of cell capacitance. Procedure and software needed because (a) some photovoltaic devices (for example, silicon solar cells with back-surface field region) store minority charge carriers in cell junction and thus exhibit significant capacitance, (b) capacitance affects current-vs.-voltage (I-V) measurements made when transient load connected to cell, and (c) transient load used in unmodified version of test procedure. Corrected I-V curve obtained in test of solar cell according to modified procedure approximates true cell voltage vs. cell current more closely.

Mueller, Robert L.

1995-01-01

476

Radiation tolerance of low resistivity, high voltage silicon solar cells  

NASA Technical Reports Server (NTRS)

The radiation tolerance of the following three low resistivity, high voltage silicon solar cells was investigated: (1) the COMSAT MSD (multi-step diffused) cell, (2) the MinMIS cell, and (3) the MIND cell. A description of these solar cells is given along with drawings of their configurations. The diffusion length damage coefficients for the cells were calculated and presented. Solar cell spectral response was also discussed. Cells of the MinMIS type were judged to be unsuitable for use in the space radiation environment.

Weizer, V. G.; Weinberg, I.; Swartz, C. K.

1984-01-01

477

Quantum Dots Investigated for Solar Cells  

NASA Technical Reports Server (NTRS)

The NASA Glenn Research Center has been investigating the synthesis of quantum dots of CdSe and CuInS2 for use in intermediate-bandgap solar cells. Using quantum dots in a solar cell to create an intermediate band will allow the harvesting of a much larger portion of the available solar spectrum. Theoretical studies predict a potential efficiency of 63.2 percent, which is approximately a factor of 2 better than any state-of-the-art devices available today. This technology is also applicable to thin-film devices--where it offers a potential four-fold increase in power-to-weight ratio over the state of the art. Intermediate-bandgap solar cells require that quantum dots be sandwiched in an intrinsic region between the photovoltaic solar cell's ordinary p- and n-type regions (see the preceding figure). The quantum dots form the intermediate band of discrete states that allow sub-bandgap energies to be absorbed. However, when the current is extracted, it is limited by the bandgap, not the individual photon energies. The energy states of the quantum dot can be controlled by controlling the