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Sample records for photovoltaic cells final

  1. 77 FR 35425 - Crystalline Silicon Photovoltaic Cells and Modules From China; Scheduling of the Final Phase of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-13

    ... COMMISSION Crystalline Silicon Photovoltaic Cells and Modules From China; Scheduling of the Final Phase of... crystalline silicon photovoltaic cells and modules, provided for in subheadings 8501.31.80, 8501.61.00, 8507... silicon photovoltaic cells, and modules, laminates, and panels, consisting of crystalline...

  2. Photovoltaic cell

    DOEpatents

    Gordon, Roy G.; Kurtz, Sarah

    1984-11-27

    In a photovoltaic cell structure containing a visibly transparent, electrically conductive first layer of metal oxide, and a light-absorbing semiconductive photovoltaic second layer, the improvement comprising a thin layer of transition metal nitride, carbide or boride interposed between said first and second layers.

  3. Transparent ultraviolet photovoltaic cells.

    PubMed

    Yang, Xun; Shan, Chong-Xin; Lu, Ying-Jie; Xie, Xiu-Hua; Li, Bing-Hui; Wang, Shuang-Peng; Jiang, Ming-Ming; Shen, De-Zhen

    2016-02-15

    Photovoltaic cells have been fabricated from p-GaN/MgO/n-ZnO structures. The photovoltaic cells are transparent to visible light and can transform ultraviolet irradiation into electrical signals. The efficiency of the photovoltaic cells is 0.025% under simulated AM 1.5 illumination conditions, while it can reach 0.46% under UV illumination. By connecting several such photovoltaic cells in a series, light-emitting devices can be lighting. The photovoltaic cells reported in this Letter may promise the applications in glass of buildings to prevent UV irradiation and produce power for household appliances in the future.

  4. Solar Photovoltaic Cells.

    ERIC Educational Resources Information Center

    Mickey, Charles D.

    1981-01-01

    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…

  5. Solar Photovoltaic Cells.

    ERIC Educational Resources Information Center

    Mickey, Charles D.

    1981-01-01

    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…

  6. Photovoltaic solar cell

    DOEpatents

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

    2013-11-26

    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.

  7. Photovoltaic solar cell

    DOEpatents

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

    2014-05-20

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

  8. Increased voltage photovoltaic cell

    NASA Technical Reports Server (NTRS)

    Ross, B.; Bickler, D. B.; Gallagher, B. D. (Inventor)

    1985-01-01

    A photovoltaic cell, such as a solar cell, is provided which has a higher output voltage than prior cells. The improved cell includes a substrate of doped silicon, a first layer of silicon disposed on the substrate and having opposite doping, and a second layer of silicon carbide disposed on the first layer. The silicon carbide preferably has the same type of doping as the first layer.

  9. Customized color patterning of photovoltaic cells

    SciTech Connect

    Cruz-Campa, Jose Luis; Nielson, Gregory N.; Okandan, Murat; Lentine, Anthony L.; Resnick, Paul J.; Gupta, Vipin P.

    2016-11-15

    Photovoltaic cells and photovoltaic modules, as well as methods of making and using such photovoltaic cells and photovoltaic modules, are disclosed. More particularly, embodiments of the photovoltaic cells selectively reflect visible light to provide the photovoltaic cells with a colorized appearance. Photovoltaic modules combining colorized photovoltaic cells may be used to harvest solar energy while providing a customized appearance, e.g., an image or pattern.

  10. Thin film photovoltaic cell

    DOEpatents

    Meakin, John D.; Bragagnolo, Julio

    1982-01-01

    A thin film photovoltaic cell having a transparent electrical contact and an opaque electrical contact with a pair of semiconductors therebetween includes utilizing one of the electrical contacts as a substrate and wherein the inner surface thereof is modified by microroughening while being macro-planar.

  11. Integrated photovoltaic electrolytic cell

    SciTech Connect

    Ohkawa, T.

    1982-10-05

    A photovoltaic-electrolytic unit is provided to produce an electric current from solar energy and utilize the current to produce hydrogen by the electrolysis of water. The unit floats in an aqueous medium so that photoelectric cells are exposed to solar radiation, and electrodes submerged in the medium produce oxygen which is vented and hydrogen which is collected in the unit.

  12. Photovoltaic research opportunities. Final report

    SciTech Connect

    Macaleer, B.; Bowers, J.; Hurlburt, B.

    1985-11-19

    The purpose of this study is to identify opportunities for photovoltaic (PV) research projects to capitalize on related but non-PV research. The study is performed under the assumption that a considerable body of ongoing semiconductor research in non-PV areas could be of value to its PV Program and the PV community in general. Research related to III-V compounds, thin films, and crystalline silicon materials is included. Research that is known to be PV-related or sponsored by DOE was excluded from consideration. The study resulted in 11 recommendations (research areas) and a subset of 58 specific research projects. In addition, over 75 non-PV research managers in the semiconductor field are identified as potential sources of ideas which could benefit photovoltaics.

  13. Photosynthetic Photovoltaic Cells

    DTIC Science & Technology

    2007-06-21

    PHOTOSYNTHETIC PHOTOVOLTAIC CELLS 5b. GRANT NUMBER F49620-02-1-0399 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER MARC A. BALDO 5e. TASK...building an ’antenna’ on top of a conventional solar cell. Biomimetic organic solar cells operate as follows: The antenna absorbs the light, and acts to...no longer must absorb all the light. Thus, its quantum efficiency can approach 100% potentially doubling the performance of organic solar cells. 15

  14. Development of a photovoltaic concentrator cell assembly for use in point focus systems. Final report

    SciTech Connect

    Not Available

    1980-12-01

    A solar cell mount assembly for use in a Fresnel lens point-focus concentrator system has been developed. This assembly uses a GE-patented direct bonded copper-on-alumina insulator to provide the required electrical isolation with a thermal resistance of less than 0.2/sup 0/C/watt between the solar cell junction and the interface of the mount with the module baseplate. High lead solder, Indalloy 151, is used to attach the cell contacts to the direct-bonded copper conductors and to attach the insulator subassembly to a copper heat spreader which provides the centrally located mounting stud for the assembly. This solder composition has demonstrated superior fatigue resistance, when compared to 60 percent tin solder, when subjected to thermal cycling in a bimetal sandwich laminate. Development cell mounts of this design have been subjected to a thermal cycling test exposure, consisting of 100 cycles between the extremes of -30 and +50/sup 0/C followed by 100 cycles between the extremes of +50 to +150/sup 0/C, without measurable changes in the thermal resistance. One thousand cell mounts of this design have been assembled and delivered to Sandia for further evaluation.

  15. Photocurrent of Photovoltaic Cells

    NASA Astrophysics Data System (ADS)

    Peeler, Seth; McIntyre, Max; Cossel, Raquel; Bowser, Chris; Tzolov, Marian

    Photovoltaic cells can be used to harness clean, renewable energy from light. Examined in this project were photovoltaic cells based on a bulk heterojunction between PCPDTBT and PCBM sandwiched between an ITO anode and an Al cathode. Current-voltage characteristics and impedance spectra for multiple photovoltaic devices were taken under varying DC electrical bias and different level of illumination. This data was interpreted in terms of an equivalent circuit with linear elements, e.g. capacitance, series resistance, and parallel resistance. A physical interpretation of each circuit element will be presented. The spectral response of the devices was characterized by optical transmission and photocurrent spectroscopy using a spectrometer in the spectral range from 300 to 900 nm. The DC measurements confirmed that the devices are electrically rectifying. The AC measurements allowed modeling of the devices as a dielectric between two electrodes with injection current passing through it. The characteristic peaks for both PCBDTBT and PCBM are clearly visible in both the photocurrent and transmission data. The good correlation between the photocurrent and transmission data indicates photocurrent generation due to absorption in both materials constituting the heterojunction.

  16. Electrochemical photovoltaic cells CdSe thin film electrodes. Final report, June 1979-June 1980

    SciTech Connect

    Russak, M.A.; Reichman, J.; DeCarlo, J.; Creter, C.

    1980-07-01

    Progress on developing stable, thin-film CdSe electrodes with sunlight conversion efficiency of 10% for use with aqueous polysulfide electrolytes in frontwall and backwall illuminated EPCs is reported. The main effort has been directed towards establishing the relationships among thin-film processing, resultant electronic properties and I-V performance in order to produce electrodes with maximum power conversion efficiency. The most encouraging results have been obtained with CdSe thin-film electrodes produced in two ways for frontwall cells. Films were deposited on titanium at approximately 100/sup 0/C with a high Se/Cd ratio and then heat treated in air at 350 to 400/sup 0/C. These films usually have a very fine grained microstructure after heat treatment and the resultant electrodes exhibit fairly square I-V characteristics with fill factors of 0.6 or greater and high current output. The overall power efficiency of these electrodes is limited by relatively low output voltages. At present, power conversion efficiencies of 3 to 5% can be obtained reproducibly at simulated AM2 conditions with electrodes processed in this manner. The second type of film that has yielded very promising results is deposited on titanium at substrate temperatures greater than 400/sup 0/C. The interesting feature of these electrodes is their increased open circuit voltage. However, the current output and fill factor are lower. As a result, the power conversion efficiency of these electrodes is 3 to 4%. Backwall electrodes with an efficiency of greater than 4% and short circuit densities near theoretical for AM2 conditions have been produced.

  17. Photovoltaic solar cell

    DOEpatents

    Nielson, Gregory N.; Gupta, Vipin P.; Okandan, Murat; Watts, Michael R.

    2015-09-08

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  18. Toward High Performance Photovoltaic Cells based on Conjugated Polymers

    DTIC Science & Technology

    2016-12-26

    AFRL-AFOSR-JP-TR-2016-0103 Toward High Performance Photovoltaic Cells based on Conjugated Polymers Kung-Hwa Wei National Chiao Tung University Final...REPORT TYPE Final 3. DATES COVERED (From - To) 16 Sep 2015 to 15 Sep 2016 4. TITLE AND SUBTITLE Toward High Performance Photovoltaic Cells based on...Grant 15IOA0113 “Toward High Performance Photovoltaic Cells Based on Conjugated Polymers (Taiwan side)” Dec. 16, 2016 PI information: Kung-Hwa Wei

  19. Graphite-based photovoltaic cells

    DOEpatents

    Lagally, Max; Liu, Feng

    2010-12-28

    The present invention uses lithographically patterned graphite stacks as the basic building elements of an efficient and economical photovoltaic cell. The basic design of the graphite-based photovoltaic cells includes a plurality of spatially separated graphite stacks, each comprising a plurality of vertically stacked, semiconducting graphene sheets (carbon nanoribbons) bridging electrically conductive contacts.

  20. Photovoltaic sub-cell interconnects

    DOEpatents

    van Hest, Marinus Franciscus Antonius Maria; Swinger Platt, Heather Anne

    2017-05-09

    Photovoltaic sub-cell interconnect systems and methods are provided. In one embodiment, a photovoltaic device comprises a thin film stack of layers deposited upon a substrate, wherein the thin film stack layers are subdivided into a plurality of sub-cells interconnected in series by a plurality of electrical interconnection structures; and wherein the plurality of electrical interconnection structures each comprise no more than two scribes that penetrate into the thin film stack layers.

  1. Interband Cascade Photovoltaic Cells

    SciTech Connect

    Yang, Rui Q.; Santos, Michael B.; Johnson, Matthew B.

    2014-09-24

    In this project, we are performing basic and applied research to systematically investigate our newly proposed interband cascade (IC) photovoltaic (PV) cells [1]. These cells follow from the great success of infrared IC lasers [2-3] that pioneered the use of quantum-engineered IC structures. This quantum-engineered approach will enable PV cells to efficiently convert infrared radiation from the sun or other heat source, to electricity. Such cells will have important applications for more efficient use of solar energy, waste-heat recovery, and power beaming in combination with mid-infrared lasers. The objectives of our investigations are to: achieve extensive understanding of the fundamental aspects of the proposed PV structures, develop the necessary knowledge for making such IC PV cells, and demonstrate prototype working PV cells. This research will focus on IC PV structures and their segments for utilizing infrared radiation with wavelengths from 2 to 5 μm, a range well suited for emission by heat sources (1,000-2,000 K) that are widely available from combustion systems. The long-term goal of this project is to push PV technology to longer wavelengths, allowing for relatively low-temperature thermal sources. Our investigations address material quality, electrical and optical properties, and their interplay for the different regions of an IC PV structure. The tasks involve: design, modeling and optimization of IC PV structures, molecular beam epitaxial growth of PV structures and relevant segments, material characterization, prototype device fabrication and testing. At the end of this program, we expect to generate new cutting-edge knowledge in the design and understanding of quantum-engineered semiconductor structures, and demonstrate the concepts for IC PV devices with high conversion efficiencies.

  2. Photovoltaic Manufacturing Technology, Phase 1, Final report

    SciTech Connect

    Easoz, J.R.; Herlocher, R.H. )

    1991-12-01

    This report examines the cost-effective manufacture of dendritic-web-based photovoltaic modules. It explains how process changes can increase production and reduce manufacturing costs. Long-range benefits of these improved processes are also discussed. Problems are identified that could impede increasing production and reducing costs; approaches to solve these problems are presented. These approaches involve web growth throughput, cell efficiency, process yield, silicon use, process control, automation, and module efficiency. Also discussed are the benefits of bifacial module design, unique to the dendritic web process.

  3. Final results of the advanced photovoltaic experiment

    NASA Technical Reports Server (NTRS)

    Brinker, David J.; Hickey, John R.

    1994-01-01

    The Advanced Photovoltaic Experiment (APEX) was designed to generate laboratory reference standards as well as to explore the durability of a wide variety of space solar cells. In addition to the cells, it was equipped with an absolute cavity radiometer to measure solar intensity, a spectroradiometer to measure the spectral content of this radiation, and a sun angle sensor. Data from the solar cells and various sensors was obtained on a daily basis during the first eleven months of the 69 month flight. We compare pre-flight and post-flight laboratory measurements with on-orbit calibration data. Pre-flight and post-flight calibration data for the cavity radiometers as well as on-orbit data demonstrated the accuracy and durability of the Eppley Labs instrument flown on APEX.

  4. Final Results of the Advanced Photovoltaic Experiment

    NASA Technical Reports Server (NTRS)

    Brinker, David J.; Hickey, John R.

    1994-01-01

    The Advanced Photovoltaic Experiment was designed to generate laboratory reference standards as well as to explore the durability of a wide variety of space solar cells. In addition to the cells, it was equipped with an absolute cavity radiometer to measure solar intensity, a spectroradiometer to measure the spectral content of this radiation and a sun angle sensor. Data from the solar cells and various sensors was obtained on a daily basis during the first eleven months of the 69 month flight. In this paper we compare pre-flight and post-flight laboratory measurements with on-orbit calibration data. Pre-flight and post-flight calibration data of the cavity radiometer as well as on-orbit data demonstrated the accuracy and durability of the Eppley Labs. instrument flown on APEX.

  5. Transparent contacts for stacked compound photovoltaic cells

    DOEpatents

    Tauke-Pedretti, Anna; Cederberg, Jeffrey; Nielson, Gregory N.; Okandan, Murat; Cruz-Campa, Jose Luis

    2016-11-29

    A microsystems-enabled multi-junction photovoltaic (MEM-PV) cell includes a first photovoltaic cell having a first junction, the first photovoltaic cell including a first semiconductor material employed to form the first junction, the first semiconductor material having a first bandgap. The MEM-PV cell also includes a second photovoltaic cell comprising a second junction. The second photovoltaic cell comprises a second semiconductor material employed to form the second junction, the second semiconductor material having a second bandgap that is less than the first bandgap, the second photovoltaic cell further comprising a first contact layer disposed between the first junction of the first photovoltaic cell and the second junction of the second photovoltaic cell, the first contact layer composed of a third semiconductor material having a third bandgap, the third bandgap being greater than or equal to the first bandgap.

  6. Photovoltaic cell and production thereof

    DOEpatents

    Narayanan, Srinivasamohan; Kumar, Bikash

    2008-07-22

    An efficient photovoltaic cell, and its process of manufacture, is disclosed wherein the back surface p-n junction is removed from a doped substrate having an oppositely doped emitter layer. A front surface and edges and optionally the back surface periphery are masked and a back surface etch is performed. The mask is not removed and acts as an anti-reflective coating, a passivating agent, or both. The photovoltaic cell retains an untextured back surface whether or not the front is textured and the dopant layer on the back surface is removed to enhance the cell efficiency. Optionally, a back surface field is formed.

  7. Photovoltaic cells employing zinc phosphide

    DOEpatents

    Barnett, Allen M.; Catalano, Anthony W.; Dalal, Vikram L.; Masi, James V.; Meakin, John D.; Hall, Robert B.

    1984-01-01

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

  8. Inverted organic photovoltaic cells.

    PubMed

    Wang, Kai; Liu, Chang; Meng, Tianyu; Yi, Chao; Gong, Xiong

    2016-05-21

    The advance in lifestyle, modern industrialization and future technological revolution are always at high expense of energy consumption. Unfortunately, there exist serious issues such as limited storage, high cost and toxic contamination in conventional fossil fuel energy sources. Instead, solar energy represents a renewable, economic and green alternative in the future energy market. Among the photovoltaic technologies, organic photovoltaics (OPVs) demonstrate a cheap, flexible, clean and easy-processing way to convert solar energy into electricity. However, OPVs with a conventional device structure are still far away from industrialization mainly because of their short lifetime and the energy-intensive deposition of top metal electrode. To address the stability and cost issue simultaneously, an inverted device structure has been introduced into OPVs, bridging laboratory research with practical application. In this review, recent progress in device structures, working mechanisms, functions and advances of each component layer as well their correlations with the efficiency and stability of inverted OPVs are reviewed and illustrated.

  9. Electrochemical photovoltaic cells and electrodes

    DOEpatents

    Skotheim, Terje A.

    1984-01-01

    Improved electrochemical photovoltaic cells and electrodes for use therein, particularly electrodes employing amorphous silicon or polyacetylene coating are produced by a process which includes filling pinholes or porous openings in the coatings by electrochemical oxidation of selected monomers to deposit insulating polymer in the openings.

  10. Linearity Testing of Photovoltaic Cells

    SciTech Connect

    Pinegar, S.; Nalley, D.; Emery, K.

    2006-01-01

    Photovoltaic devices are rated in terms of their power output or efficiency with respect to a specific spectrum, total irradiance, and temperature. In order to rate photovoltaic devices, a reference detector whose response is linear with total irradiance is needed. This procedure documents a procedure to determine if a detector is linear over the irradiance range of interest. Testing the short circuit current versus the total irradiance is done by illuminating a reference cell candidate with two lamps that are fitted with programmable filter wheels. The purpose is to reject nonlinear samples as determined by national and international standards from being used as primary reference cells. A calibrated linear reference cell tested by the two lamp method yields a linear result.

  11. Photovoltaic cell with thin CS layer

    SciTech Connect

    Jordan, J.F.; Albright, S.P.

    1994-01-18

    An improved photovoltaic panel and method of forming a photovoltaic panel are disclosed for producing a high efficiency CdS/CdTe photovoltaic cell. The photovoltaic panel of the present invention is initially formed with a substantially thick CdS layer, and the effective thickness of the CdS layer is substantially reduced during regrowth to both form larger diameter CdTe crystals and substantially reduce the effective thickness of the CdS layer. 4 figures.

  12. High Performance Photovoltaic Solar Cells: Cooperative Research and Development Final Report, CRADA Number CRD-05-169

    SciTech Connect

    Steiner, M.

    2012-07-01

    NREL will provide certified measurements of the conversion efficiency at high concentration for several multijunction solar cells that were fabricated by Cyrium Technologies. In an earlier phase of the CRADA, Cyrium provided epitaxially-grown material and NREL processed the samples into devices and measured the performance.

  13. Method of making photovoltaic cell

    DOEpatents

    Cruz-Campa, Jose Luis; Zhou, Xiaowang; Zubia, David

    2017-06-20

    A photovoltaic solar cell comprises a nano-patterned substrate layer. A plurality of nano-windows are etched into an intermediate substrate layer to form the nano-patterned substrate layer. The nano-patterned substrate layer is positioned between an n-type semiconductor layer composed of an n-type semiconductor material and a p-type semiconductor layer composed of a p-type semiconductor material. Semiconductor material accumulates in the plurality of nano-windows, causing a plurality of heterojunctions to form between the n-type semiconductor layer and the p-type semiconductor layer.

  14. Electrochemical photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Ang, P. G. P.; Sammells, A. F.

    1980-09-01

    Increasing solar energy conversion efficiencies and identifying potentially long-life systems were emphasized. Semiconductor/redox couple systems were selected on the basis of the apparent positions of their conduction and valence band energy levels at the interface, together with the semiconductor decomposition potential. Selected redox couples should possess equilibrium potentials that lie negative of the semiconductor decomposition potential and positive of the semiconductor conduction band. Liquid-junction solar cells were characterized using n-MoSe2, N-MoS2, n-WSe2, n-CdSe, and n-GaAs as photo-anodes.

  15. Photovoltaic mechanisms in polycrystalline thin film silicon solar cells. Final report, 30 June 1979-29 June 1980

    SciTech Connect

    Sopori, B.L.

    1980-11-01

    The objectives of this program were: (1) to develop appropriate measurement techniques to facilitate a quantitative study of the electrical activity of structural defects and at a grain boundary (G.B.) in terms of generation-recombination, barrier height, and G.B. conductivity; (2) to characterize G.B.s in terms of physical properties such as angle of misfit and local stress, and to correlate them with the electrical activity; (3) to determine the influence of solar cell processing on the electrical behavior of structural defects and G.B.s; and (4) to evaluate polycrystalline solar cell performance based on the above study, and to compare it with the experimentally measured performance. Progress is reported in detail. (WHK)

  16. Photovoltaic Technologies Beyond the Horizon: Optical Rectenna Solar Cell, Final Report, 1 August 2001-30 September 2002

    SciTech Connect

    Berland, B.

    2003-02-01

    ITN Energy Systems is developing next-generation solar cells based on the concepts of an optical rectenna. ITN's optical rectenna consists of two key elements: (1) an optical antenna to efficiently absorb the incident solar radiation, and (2) a high-frequency metal-insulator-metal (MIM) tunneling diode that rectifies the AC field across the antenna, providing DC power to an external load. The combination of a rectifying diode at the feedpoints of a receiving antenna is often referred to as a rectenna. Rectennas were originally proposed in the 1960s for power transmission by radio waves for remote powering of aircraft for surveillance or communications platforms. Conversion efficiencies greater than 85% have been demonstrated at radio frequencies (efficiency defined as DC power generated divided by RF power incident on the device). Later, concepts were proposed to extend the rectennas into the IR and optical region of the electromagnetic spectrum for use as energy collection devices (optical rectennas).

  17. Photovoltaic cell with thin CS layer

    DOEpatents

    Jordan, John F.; Albright, Scot P.

    1994-01-18

    An improved photovoltaic panel and method of forming a photovoltaic panel are disclosed for producing a high efficiency CdS/CdTe photovoltaic cell. The photovoltaic panel of the present invention is initially formed with a substantially thick Cds layer, and the effective thickness of the CdS layer is substantially reduced during regrowth to both form larger diameter CdTe crystals and substantially reduce the effective thickness of the C This invention was made with Government support under Subcontract No. ZL-7-06031-3 awarded by the Department of Energy. The Government has certain rights in this invention.

  18. Development of a High Volume Capable Process to Manufacture High Performance Photovoltaic Cells: Cooperative Research and Development Final Report, CRADA Number CRD-08-322

    SciTech Connect

    Geisz, J. F.

    2012-11-01

    The intent of the work is for RFMD and NREL to cooperate in the development of a commercially viable and high volume capable process to manufacture high performance photovoltaic cells, based on inverted metamorphic (IMM) GaAs technology. The successful execution of the agreement will result in the production of a PV cell using technology that is capable of conversion efficiency at par with the market at the time of release (reference 2009: 37-38%), using RFMD's production facilities. The CRADA work has been divided into three phases: (1) a foundation phase where the teams will demonstrate the manufacturing of a basic PV cell at RFMD's production facilities; (2) a technology demonstration phase where the teams will demonstrate the manufacturing of prototype PV cells using IMM technology at RFMD's production facilities, and; (3) a production readiness phase where the teams will demonstrate the capability to manufacture PV cells using IMM technology with high yields, high reliability, high reproducibility and low cost.

  19. Photovoltaic-system costing-methodology development. Final report

    SciTech Connect

    Not Available

    1982-07-01

    Presented are the results of a study to expand the use of standardized costing methodologies in the National Photovoltaics Program. The costing standards, which include SAMIS for manufacturing costs and M and D for marketing and distribution costs, have been applied to concentrator collectors and power-conditioning units. The M and D model was also computerized. Finally, a uniform construction cost-accounting structure was developed for use in photovoltaic test and application projects. The appendices contain example cases which demonstrate the use of the models.

  20. Photovoltaic subsystem marketing and distribution model: programming manual. Final report

    SciTech Connect

    Not Available

    1982-07-01

    Complete documentation of the marketing and distribution (M and D) computer model is provided. The purpose is to estimate the costs of selling and transporting photovoltaic solar energy products from the manufacturer to the final customer. The model adjusts for the inflation and regional differences in marketing and distribution costs. The model consists of three major components: the marketing submodel, the distribution submodel, and the financial submodel. The computer program is explained including the input requirements, output reports, subprograms and operating environment. The program specifications discuss maintaining the validity of the data and potential improvements. An example for a photovoltaic concentrator collector demonstrates the application of the model.

  1. Photovoltaic industry manufacturing technology. Final report

    SciTech Connect

    Vanecek, D.; Diver, M.; Fernandez, R.

    1998-08-01

    This report contains the results of the Photovoltaic (PV) Industry Manufacturing Technology Assessment performed by the Automation and Robotics Research Institute (ARRI) of the University of Texas at Arlington for the National Renewable Energy laboratory. ARRI surveyed eleven companies to determine their state-of-manufacturing in the areas of engineering design, operations management, manufacturing technology, equipment maintenance, quality management, and plant conditions. Interviews with company personnel and plant tours at each of the facilities were conducted and the information compiled. The report is divided into two main segments. The first part of the report presents how the industry as a whole conforms to ``World Class`` manufacturing practices. Conclusions are drawn from the results of a survey as to the areas that the PV industry can improve on to become more competitive in the industry and World Class. Appendix A contains the questions asked in the survey, a brief description of the benefits to performing this task and the aggregate response to the questions. Each company participating in the assessment process received the results of their own facility to compare against the industry as a whole. The second part of the report outlines opportunities that exist on the shop floor for improving Process Equipment and Automation Strategies. Appendix B contains the survey that was used to assess each of the manufacturing processes.

  2. Photovoltaics effective capacity: Interim final report 2

    SciTech Connect

    Perez, R.; Seals, R.

    1997-11-01

    The authors provide solid evidence, based on more than 8 million data points, that regional photovoltaic (PV) effective capacity is largely unrelated to the region`s solar resource. They confirm, however, that effective capacity is strongly related to load-shape characteristics. The load-shape effective-capacity relationship appears to be valid for end-use loads as small as 100 kW, except possibly in the case of electrically heated buildings. This relationship was used as a tool to produce a US map of PV`s effective capacity. The regions of highest effective capacities include (1) the central US from the northern Great Plains to the metropolitan areas of Chicago and Detroit, down to the lower Mississippi Valley, (2) California and western Arizona, and (3) the northeast metropolitan corridor. The features of this map are considerably different from the traditional solar resource maps. They tend to reflect the socio-economic and climatic factors that indirectly drive PV`s effective capacity: e.g., commercial air-conditioning, little use of electric heat, and strong summer heat waves. The map provides a new and significant insight to a comprehensive valuation of the PV resource. The authors assembled preliminary evidence showing that end-use load type may be related to PV`s effective capacity. Highest effective capacities were found for (nonelectrically heated) office buildings, followed by hospitals. Lowest capacities were found for airports and residences. Many more data points are needed, however, to ascertain and characterize these preliminary findings.

  3. Carbon nanotube--poly(3-octylthiophene) composite photovoltaic cells.

    PubMed

    Carroll, David L; Czerw, Richard; Harrison, Benjamin

    2006-07-01

    The effects of varying nanotube loading/concentration in carbon nanotube-poly(3-octylthiophene) blends used as thin film photovoltaic cells, have been studied. The network of single walled nanotubes clearly aids in exciton separation and modifies carrier mobility within the active layer as suggested by a bulk heterojunction model. Further, modifications to the metal-polymer interface occur with the addition of nanotubes leading to variations in the observed VOC of the photovoltaic cells. Finally, the "nanocomposite" devices exhibit significant enhancements to external power conversion efficiencies, with the overall efficiency strongly dependent on device design parameters such as the addition of buffer layers.

  4. Quantum well multijunction photovoltaic cell

    DOEpatents

    Chaffin, R.J.; Osbourn, G.C.

    1983-07-08

    A monolithic, quantum well, multilayer photovoltaic cell comprises a p-n junction comprising a p-region on one side and an n-region on the other side, each of which regions comprises a series of at least three semiconductor layers, all p-type in the p-region and all n-type in the n-region; each of said series of layers comprising alternating barrier and quantum well layers, each barrier layer comprising a semiconductor material having a first bandgap and each quantum well layer comprising a semiconductor material having a second bandgap when in bulk thickness which is narrower than said first bandgap, the barrier layers sandwiching each quantum well layer and each quantum well layer being sufficiently thin that the width of its bandgap is between said first and second bandgaps, such that radiation incident on said cell and above an energy determined by the bandgap of the quantum well layers will be absorbed and will produce an electrical potential across said junction.

  5. Quantum well multijunction photovoltaic cell

    DOEpatents

    Chaffin, Roger J.; Osbourn, Gordon C.

    1987-01-01

    A monolithic, quantum well, multilayer photovoltaic cell comprises a p-n junction comprising a p-region on one side and an n-region on the other side, each of which regions comprises a series of at least three semiconductor layers, all p-type in the p-region and all n-type in the n-region; each of said series of layers comprising alternating barrier and quantum well layers, each barrier layer comprising a semiconductor material having a first bandgap and each quantum well layer comprising a semiconductor material having a second bandgap when in bulk thickness which is narrower than said first bandgap, the barrier layers sandwiching each quantum well layer and each quantum well layer being sufficiently thin that the width of its bandgap is between said first and second bandgaps, such that radiation incident on said cell and above an energy determined by the bandgap of the quantum well layers will be absorbed and will produce an electrical potential across said junction.

  6. Photovoltaic solar concentrator

    DOEpatents

    Nielson, Gregory N.; Cruz-Campa, Jose Luis; Okandan, Murat; Resnick, Paul J.; Sanchez, Carlos Anthony; Clews, Peggy J.; Gupta, Vipin P.

    2015-09-08

    A process including forming a photovoltaic solar cell on a substrate, the photovoltaic solar cell comprising an anchor positioned between the photovoltaic solar cell and the substrate to suspend the photovoltaic solar cell from the substrate. A surface of the photovoltaic solar cell opposite the substrate is attached to a receiving substrate. The receiving substrate may be bonded to the photovoltaic solar cell using an adhesive force or a metal connecting member. The photovoltaic solar cell is then detached from the substrate by lifting the receiving substrate having the photovoltaic solar cell attached thereto and severing the anchor connecting the photovoltaic solar cell to the substrate. Depending upon the type of receiving substrate used, the photovoltaic solar cell may be removed from the receiving substrate or remain on the receiving substrate for use in the final product.

  7. Nanoparticle-polymer photovoltaic cells.

    PubMed

    Saunders, Brian R; Turner, Michael L

    2008-04-21

    The need to develop and deploy large-scale, cost-effective, renewable energy is becoming increasingly important. In recent years photovoltaic (PV) cells based on nanoparticles blended with semiconducting polymers have achieved good power conversion efficiencies (PCE). All the nanoparticle types used in these PV cells can be considered as colloids. These include spherical, rod-like or branched organic or inorganic nanoparticles. Nanoparticle-polymer PV cells have the long-term potential to provide low cost, high-efficiency renewable energy. The maximum PCE achieved to date is about 5.5%. This value should rise as recently reported theoretical predictions suggest 10% is achievable. However, there are a number of challenges that remain to be overcome. In this review two general types of nanoparticle-polymer PV cells are considered and compared in detail. The organic nanoparticle-polymer PV cells contain fullerene derivatives (e.g., phenyl C61-butyric acid methyl ester, PCBM) or single-walled nanotubes as the nanoparticle phase. The second type is hybrid inorganic nanoparticle-polymer PV cells. These contain semiconducting nanoparticles that include CdSe, ZnO or PbS. The structure-property relationships that apply to both the polymer and nanoparticle phases are considered. The principles underlying nanoparticle-polymer PV cell operation are also discussed. An outcome of consideration of the literature in both areas are two sets of assembly conditions that are suggested for constructing PCBM-P3HT (P3HT is poly(3-hexylthiophene)) or CdSe-P3HT PV cells with reasonable power conversion efficiency. The maximum PCE reported for organic nanoparticle PV cells is about twice that for inorganic nanoparticle-polymer PV cells. This appears to be related to morphological differences between the respective photoactive layers. The morphological differences are attributed to differences in the colloidal stability of the nanoparticle/polymer/solvent mixtures used to prepare the

  8. Conjugated ionomers for photovoltaic applications: electric field driven charge separation in organic photovoltaics. Final Technical report

    SciTech Connect

    Lonergan, Mark

    2015-05-29

    Final technical report for Conjugated ionomers for photovoltaic applications, electric field driven charge separation in organic photovoltaics. The central goal of the work we completed was been to understand the photochemical and photovoltaic properties of ionically functionalized conjugated polymers (conjugated ionomers or polyelectrolytes) and energy conversion systems based on them. We primarily studied two classes of conjugated polymer interfaces that we developed based either upon undoped conjugated polymers with an asymmetry in ionic composition (the ionic junction) or doped conjugated polymers with an asymmetry in doping type (the p-n junction). The materials used for these studies have primarily been the polyacetylene ionomers. We completed a detailed study of p-n junctions with systematically varying dopant density, photochemical creation of doped junctions, and experimental and theoretical work on charge transport and injection in polyacetylene ionomers. We have also completed related work on the use of conjugated ionomers as interlayers that improve the efficiency or organic photovoltaic systems and studied several important aspects of the chemistry of ionically functionalized semiconductors, including mechanisms of so-called "anion-doping", the formation of charge transfer complexes with oxygen, and the synthesis of new polyfluorene polyelectrolytes. We also worked worked with the Haley group at the University of Oregon on new indenofluorene-based organic acceptors.

  9. Semiconductor nanostructure-based photovoltaic solar cells

    NASA Astrophysics Data System (ADS)

    Zhang, Genqiang; Finefrock, Scott; Liang, Daxin; Yadav, Gautam G.; Yang, Haoran; Fang, Haiyu; Wu, Yue

    2011-06-01

    Substantial efforts have been devoted to design, synthesize, and integrate various semiconductor nanostructures for photovoltaic (PV) solar cells. In this article, we will review the recent progress in this exciting area and cover the material chemistry and physics related to all-inorganic nanostructure solar cells, hybrid inorganic nanostructure-conductive polymer composite solar cells, and dye-sensitized solar cells.

  10. Semiconductor nanostructure-based photovoltaic solar cells.

    PubMed

    Zhang, Genqiang; Finefrock, Scott; Liang, Daxin; Yadav, Gautam G; Yang, Haoran; Fang, Haiyu; Wu, Yue

    2011-06-01

    Substantial efforts have been devoted to design, synthesize, and integrate various semiconductor nanostructures for photovoltaic (PV) solar cells. In this article, we will review the recent progress in this exciting area and cover the material chemistry and physics related to all-inorganic nanostructure solar cells, hybrid inorganic nanostructure-conductive polymer composite solar cells, and dye-sensitized solar cells.

  11. Commercial Application of a Photovoltaic Concentrator system. Phase I. Final report, 1 June 1978-28 February 1979

    SciTech Connect

    Anderson, D.J.; Anderson, E.R.; Bardwell, K.M.

    1980-04-01

    This report documents the design and analysis of the BDM CAPVC (Commercial Application of a Photovoltaic Concentrator) system. The preliminary design, prototype test and evaluation, system analysis, and final design of a large-scale concentrating photovoltaic system are described. The application is on an attractive new office building which represents a large potential market. The photovoltaic concentrating array is a roof-mounted, single-axis linear parabolic trough, using single crystalline silicon photovoltaic cells. A total of 6720 square feet of aperture is focussed on 13,944 PV cells. The photovoltaic system operates in parallel with the local utility in an augmentary loadsharing operating mode. The array is actively cooled and the thermal energy utilized for building heat during winter months. (WHK)

  12. Cost-effective flat-plate photovoltaic modules using light trapping. Final report

    SciTech Connect

    Bain, C.N.; Gordon, B.A.; Knasel, T.M.; Malinowski, R.L.

    1981-04-01

    Work in optical trapping in thick films is extended to form a design guide for photovoltaic engineers. Details of the methods, techniques, and considerations that are used in the definition and analysis of light trapping photovoltaic panels are provided. Assumptions, sources of data, optical and cost modeling methods and the techniques used in the analysis are included. The ways to use light trapping are discussed, and methods are described to use simplified design and costing equations to predict performance and cost benefits. Four significant ways to use the findings presented are: a minimum design change module; an optimum packing factor module concept; roof or wall integrated panels; and modules using light trapping from cell grids. Finally, a design guide is included which shows how to construct photovoltaic modules to exploit light trapping. It is claimed that up to 20% improvements in standard module performance can be expected. (LEW)

  13. Tandem junction amorphous semiconductor photovoltaic cell

    DOEpatents

    Dalal, V.L.

    1983-06-07

    A photovoltaic stack comprising at least two p[sup +]i n[sup +] cells in optical series, said cells separated by a transparent ohmic contact layer(s), provides a long optical path for the absorption of photons while preserving the advantageous field-enhanced minority carrier collection arrangement characteristic of p[sup +]i n[sup +] cells. 3 figs.

  14. Tandem junction amorphous semiconductor photovoltaic cell

    DOEpatents

    Dalal, Vikram L.

    1983-01-01

    A photovoltaic stack comprising at least two p.sup.+ i n.sup.+ cells in optical series, said cells separated by a transparent ohmic contact layer(s), provides a long optical path for the absorption of photons while preserving the advantageous field-enhanced minority carrier collection arrangement characteristic of p.sup.+ i n.sup.+ cells.

  15. Measuring The Contact Resistances Of Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Burger, D. R.

    1985-01-01

    Simple method devised to measure contact resistances of photovoltaic solar cells. Method uses readily available equipment and applicable at any time during life of cell. Enables evaluation of cell contact resistance, contact-end resistance, contact resistivity, sheet resistivity, and sheet resistivity under contact.

  16. Design to improve photoelectric efficiency for photovoltaic cell array for laser power beaming

    NASA Astrophysics Data System (ADS)

    Li, Xiaojiang; Li, Beibei

    2017-02-01

    Photovoltaic cell (PV) array is a photovoltaic conversion device for laser power beaming, and uneven distribution of laser beam energy will have negative influence on the photovoltaic efficiency of PV array. In order to improve the photovoltaic efficiency under uneven laser irradiation, an optimized and efficient parallel-series PV array is designed. Based on the mathematical model and MATLB/Simulink simulation model of PV array , the influencing factors of photovoltaic efficiency are analyzed, and the concept and scheme to improve the photovoltaic efficiency of parallel-series PV array are proposed. Finally, compared with typical PV array, the effects improving efficiency of optimized array is simulated and analyzed. The simulation results show that under uneven laser irradiation, the optimized parallel-series PV array can obtain higher photovoltaic efficiency.

  17. Study of Photovoltaic Cells Engineering Mathematical Model

    NASA Astrophysics Data System (ADS)

    Zhou, Jun; Yu, Zhengping; Lu, Zhengyi; Li, Chenhui; Zhang, Ruilan

    2016-11-01

    The characteristic curve of photovoltaic cells is the theoretical basis of PV Power, which simplifies the existing mathematical model, eventually, obtains a mathematical model used in engineering. The characteristic curve of photovoltaic cells contains both exponential and logarithmic calculation. The exponential and logarithmic spread out through Taylor series, which includes only four arithmetic and use single chip microcontroller as the control center. The result shows that: the use of single chip microcontroller for calculating exponential and logarithmic functions, simplifies mathematical model of PV curve, also can meet the specific conditions’ requirement for engineering applications.

  18. Photovoltaic concentrator with plastic-film reflector. Final report

    SciTech Connect

    Not Available

    1982-06-01

    A 4m diameter reflective film, parabolic dish concentrator proposed for use with a photovoltaic array has been designed, fabricated, and tested. The concentrator is made from aluminized film gores (wedge shaped pieces) that are taped together along their edges to form a dish. The shape of the dish is maintained by a pressure difference between the front and back. The deep dish was designed to illuminate a cylindrical receiver populated by solar cells with a geometric concentration ratio of 145. Three full scale dishes were made in sequence, each using improvements suggested by the previous design. They were tested with a laser to determine surface errors and flux uniformity on the target.

  19. Photovoltaic Cell And Manufacturing Process

    DOEpatents

    Albright, Scot P.; Chamberlin, Rhodes R.

    1996-11-26

    Provided is a method for controlling electrical properties and morphology of a p-type material of a photovoltaic device. The p-type material, such as p-type cadmium telluride, is first subjected to heat treatment in an oxidizing environment, followed by recrystallization in an environment substantially free of oxidants. In one embodiment, the heat treatment step comprises first subjecting the p-type material to an oxidizing atmosphere at a first temperature to getter impurities, followed by second subjecting the p-type material to an oxidizing atmosphere at a second temperature, higher than the first temperature, to develop a desired oxidation gradient through the p-type material.

  20. Final Results of the Advanced Photovoltaic Experiment Flight Test

    NASA Technical Reports Server (NTRS)

    Brinker, David J.; Hickey, John R.

    1995-01-01

    The Advanced Photovoltaic Experiment was designed to generate laboratory reference standards as well as to explore the durability of a wide variety of space solar cells. In addition to the cells, it was equipped with an absolute cavity radiometer to measure solar intensity, a spectroradiometer to measure the spectral content of this radiation and a sun angle sensor. Data from the solar cells and various sensors was obtained on a daily basis during the first eleven months of the 69 month flight. In this paper pre-flight and post-flight laboratory measurements are compared with on-orbit calibration data. Pre-flight and post-flight calibration data of the cavity radiometer as well as on-orbit data demonstrated the accuracy and durability of the Eppley instrument flown on APEX.

  1. Socioeconomic impact of photovoltaic power at Schuchulik, Arizona. Final report

    SciTech Connect

    Bahr, D.; Garrett, B.G.; Chrisman, C.

    1980-10-01

    Schuchuli, a small remote village on the Papago Indian Reservation in southwest Arizona, is 27 kilometers (17 miles) from the nearest available utility power. In some respects, Schuchuli resembles many of the rural villages in other parts of the world. For example, it's relatively small in size (about 60 residents), composed of a number of extended family groupings, and remotely situated relative to major population centers (190 km, or 120 miles, from Tucson). Its lack of conventional power is due to the prohibitive cost of supplying a small electrical load with a long-distance distribution line. Furthermore, alternate energy sources are expensive and place a burden on the resources of the villagers. On December 16, 1978, as part of a federally funded project, a solar cell power system was put into operation at Schuchuli. The system powers the village water pump, lighting for homes ad other village buildings, family refrigerators and a communal washing machine and sewing machine. The project, managed for the US Department of Energy by the NASA Lewis Research Center, provided for a one-year socio-economic study to assess the impact of a relatively small amount of electricity on the basic living environment of the villagers. The results of that study are presented, including village history, group life, energy use in general and the use of the photovoltaic-powered appliances. No significant impacts due to the photovoltaic power system were observed.

  2. Pulsed laser illumination of photovoltaic cells

    NASA Technical Reports Server (NTRS)

    Yater, Jane A.; Lowe, Roland A.; Jenkins, Phillip P.; Landis, Geoffrey A.

    1994-01-01

    In future space missions, free electron lasers (FEL) may be used to illuminate photovoltaic array receivers to provide remote power. Both the radio-frequency (RF) and induction FEL provide FEL produce pulsed rather than continuous output. In this work we investigate cell response to pulsed laser light which simulates the RF FEL format. The results indicate that if the pulse repetition is high, cell efficiencies are only slightly reduced compared to constant illumination at the same wavelength. The frequency response of the cells is weak, with both voltage and current outputs essentially dc in nature. Comparison with previous experiments indicates that the RF FEL pulse format yields more efficient photovoltaic conversion than does an induction FEL pulse format.

  3. Pulsed laser illumination of photovoltaic cells

    NASA Technical Reports Server (NTRS)

    Yater, Jane A.; Lowe, Roland A.; Jenkins, Phillip P.; Landis, Geoffrey A.

    1995-01-01

    In future space missions, free electron lasers (FEL) may be used to illuminate photovoltaic receivers to provide remote power. Both the radio-frequency (RF) and induction FEL produce pulsed rather than continuous output. In this work we investigate cell response to pulsed laser light which simulates the RF FEL format. The results indicate that if the pulse repetition is high, cell efficiencies are only slightly reduced compared to constant illumination at the same wavelength. The frequency response of the cells is weak, with both voltage and current outputs essentially dc in nature. Comparison with previous experiments indicates that the RF FEL pulse format yields more efficient photovoltaic conversion than does an induction FEL format.

  4. University Photovoltaic Research, Education, and Collaboration. Final Report

    SciTech Connect

    Rohatgi, Ajeet; Ebong, Abasifreke; Kim, Dong Seop; Yelundur, Vijay; Hilali, Mohamed M.; Rounsaville, Brian; Nakayashiki, Kenta; Meemongkolkiat, Vichai

    2007-03-30

    This report summarizes the progress made by Georgia Tech in the 2000-2006 period towards high-efficiency low-cost crystalline silicon solar cells. The overall goal of the program is to advance the current state of crystalline silicon solar cell technology in order to make photovoltaics more competitive with the conventional energy sources. A combination of material characterization, device modeling, low-cost technology development, cell fabrication and analysis have been used to achieve the goals of this program. Quality enhancement techniques have been developed to achieve high lifetime in commercial substrates. At the same time, advanced concepts and cell designs were developed to achieve high-efficiency cells on low-cost substrates. Low-cost in-line processing, novel diffusion techniques, and improved and screen-printed contacts were used to incorporate advanced design features in commercial cells. The program has also focused on the development of screen-printing pastes and contact firing to obtain high fill factors on high sheet resistance emitters with narrow grid lines. This report is divided into seven sections that summarize our work on i) high-efficiency monocrystalline cells through the achievement of ohmic contacts to high sheet resistance emitters by screen printing (Sections 1 and 2); ii) process and material factors that limit the potential of the Al-doped back surface field (Sections 3 and 4); iii) high-efficiency cells on low-cost multicrystalline wafers through defect gettering and passivation (Section 5); iv) low-cost phosphorus emitter diffusion in a novel in-line furnace (Section 6); and iv) the development of a 2D model to determine the effects of physical cell parameters on the performance of IBC (interdigitated back contact) solar cells (Section 7).

  5. Colored dual-functional photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Lee, Kyu-Tae; Lee, Jae Yong; Xu, Ting; Park, Hui Joon; Guo, L. Jay

    2016-06-01

    In this article, we review our recent efforts on multi-functional photovoltaic (PV) cells that can produce desired reflective, transmissive, or neutral colors, by controlling light interaction with semiconductors and electrode structures in a desired manner. The PV cells integrated with plasmonic color filtering schemes using subwavelength gratings, and other approaches exploiting photonic resonances in an optical nanocavity consisting of highly absorbing semiconductor media are described. For further enhancement of optical and electrical performance characteristics of the multi-functional PV cells, possible difficulties and the outlook for future work are discussed.

  6. Cell shunt resistance and photovoltaic module performance

    SciTech Connect

    McMahon, T.J.; Basso, T.S.; Rummel, S.R.

    1996-09-01

    Shunt resistance of cells in photovoltaic modules can affect module power output and could indicate flawed manufacturing processes and reliability problems. The authors describe a two-terminal diagnostic method to directly measure the shunt resistance of individual cells in a series-connected module non-intrusively, without deencapsulation. Peak power efficiency vs. light intensity was measured on a 12-cell, series-connected, single crystalline module having relatively high cell shunt resistances. The module was remeasured with 0.5-, 1-, and 2-ohm resistors attached across each cell to simulate shunt resistances of several emerging technologies. Peak power efficiencies decreased dramatically at lower light levels. Using the PSpice circuit simulator, they verified that cell shunt and series resistances can indeed be responsible for the observed peak power efficiency vs. intensity behavior. They discuss the effect of basic cell diode parameters, i.e., shunt resistance, series resistance, and recombination losses, on PV module performance as a function of light intensity.

  7. 77 FR 14732 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-13

    ... International Trade Administration Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules... of crystalline silicon photovoltaic cells, whether or not assembled into modules, from the People's.... \\1\\ See Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From...

  8. Dye Sensitized Tandem Photovoltaic Cells

    SciTech Connect

    Barber, Greg D.

    2009-12-21

    This work provided a new way to look at photoelectrochemical cells and their performance. Although thought of as low efficiency, a the internal efficiency of a 9% global efficiency dye sensitized solar cell is approximately equal to an 18% efficient silicon cell when each is compared to their useful spectral range. Other work undertaken with this contract also reported the first growth oriented titania and perovskite columns on a transparent conducting oxide. Other work has shown than significant performance enhancement in the performance of dye sensitized solar cells can be obtained through the use of coupling inverse opal photonic crystals to the nanocrystalline dye sensitized solar cell. Lastly, a quick efficient method was developed to bond titanium foils to transparent conducting oxide substrates for anodization.

  9. An induced junction photovoltaic cell

    NASA Technical Reports Server (NTRS)

    Call, R. L.

    1974-01-01

    Silicon solar cells operating with induced junctions rather than diffused junctions have been fabricated and tested. Induced junctions were created by forming an inversion layer near the surface of the silicon by supplying a sheet of positive charge above the surface. Measurements of the response of the inversion layer cell to light of different wavelengths indicated it to be more sensitive to the shorter wavelengths of the sun's spectrum than conventional cells. The greater sensitivity occurs because of the shallow junction and the strong electric field at the surface.

  10. Photovoltaic Cell Operation on Mars

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Kerslake, Thomas; Jenkins, Phillip P.; Scheiman, David A.

    2004-01-01

    The Martian surface environment provides peculiar challenges for the operation of solar arrays: low temperature, solar flux with a significant scattered component that varies in intensity and spectrum with the amount of suspended atmospheric dust, and the possibility of performance loss due to dust deposition on the array surface. This paper presents theoretical analyses of solar cell performance on the surface of Mars and measurements of cells under Martian conditions.

  11. Pulsed Laser Illumination of Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Yater, Jane A.; Lowe, Roland; Jenkins, Philip; Landis, Geoffrey A.

    1994-01-01

    In future space missions, free electron lasers (FEL) may be used to illuminate photovoltaic array receivers to provide remote power. The induction FEL and the radio-frequency (RF) FEL both produce pulsed rather than continuous output. In this work, we investigate cell response to pulsed laser light which simulates the RF FEL format, producing 50 ps pulses at a frequency of 78 MHz. A variety of Si, GaAs, CaSb and CdInSe2 (CIS) solar cells are tested at average incident powers between 4 mW/sq cm and 425 mW/sq cm. The results indicate that if the pulse repetition is high, cell efficiencies are only slightly reduced by using a pulsed laser source compared to constant illumination at the same wavelength. Because the pulse separation is less than or approximately equal to the minority carrier lifetime, the illumination conditions are effectively those of a continuous wave laser. The time dependence of the voltage and current response of the cells are also measured using a sampling oscilloscope equipped with a high frequency voltage probe and current transformer. The frequency response of the cells is weak, with both voltage and current outputs essentially dc in nature. Comparison with previous experiments shows that the RF FEL pulse format yields much more efficient photovoltaic conversion of light than does an induction FEL pulse format.

  12. Pulsed Laser Illumination of Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Yater, Jane A.; Lowe, Roland; Jenkins, Philip; Landis, Geoffrey A.

    1994-01-01

    In future space missions, free electron lasers (FEL) may be used to illuminate photovoltaic array receivers to provide remote power. The induction FEL and the radio-frequency (RF) FEL both produce pulsed rather than continuous output. In this work, we investigate cell response to pulsed laser light which simulates the RF FEL format, producing 50 ps pulses at a frequency of 78 MHz. A variety of Si, GaAs, CaSb and CdInSe2 (CIS) solar cells are tested at average incident powers between 4 mW/sq cm and 425 mW/sq cm. The results indicate that if the pulse repetition is high, cell efficiencies are only slightly reduced by using a pulsed laser source compared to constant illumination at the same wavelength. Because the pulse separation is less than or approximately equal to the minority carrier lifetime, the illumination conditions are effectively those of a continuous wave laser. The time dependence of the voltage and current response of the cells are also measured using a sampling oscilloscope equipped with a high frequency voltage probe and current transformer. The frequency response of the cells is weak, with both voltage and current outputs essentially dc in nature. Comparison with previous experiments shows that the RF FEL pulse format yields much more efficient photovoltaic conversion of light than does an induction FEL pulse format.

  13. Photovoltaic-cell technologies joust for position

    NASA Astrophysics Data System (ADS)

    Fischetti, M. A.

    1984-03-01

    The three most promising photovoltaic cell technologies, single-crystal-silicon cells, polycrystalline thin films, and amorphous silicon thin films, are reviewed and discussed in terms of present levels of applicability and the prospects for domination of PV markets in the future. A U.S. DOE research plan running from 1984 to 1988 which aims to produce PV modules that will generate electricity at $.20/kWh by 1988 is outlined, and R & D efforts in Japan and Europe are considered. Although GaAs cells have reached efficiencies to 20 percent in the laboratory, the most successful commercial products have been single-crystal-silicon cells with efficiencies between 11 and 12 percent. It is suggested that the immiment rise of amorphous silicon in the late 1980s may thwart polycrystalline-cell development before it has a chance to flourish.

  14. Terrestrial photovoltaic cell process testing

    NASA Technical Reports Server (NTRS)

    Burger, D. R.

    1985-01-01

    The paper examines critical test parameters, criteria for selecting appropriate tests, and the use of statistical controls and test patterns to enhance PV-cell process test results. The coverage of critical test parameters is evaluated by examining available test methods and then screening these methods by considering the ability to measure those critical parameters which are most affected by the generic process, the cost of the test equipment and test performance, and the feasibility for process testing.

  15. Photovoltaic cell with nano-patterned substrate

    DOEpatents

    Cruz-Campa, Jose Luis; Zhou, Xiaowang; Zubia, David

    2016-10-18

    A photovoltaic solar cell comprises a nano-patterned substrate layer. A plurality of nano-windows are etched into an intermediate substrate layer to form the nano-patterned substrate layer. The nano-patterned substrate layer is positioned between an n-type semiconductor layer composed of an n-type semiconductor material and a p-type semiconductor layer composed of a p-type semiconductor material. Semiconductor material accumulates in the plurality of nano-windows, causing a plurality of heterojunctions to form between the n-type semiconductor layer and the p-type semiconductor layer.

  16. Potential high efficiency solar cells: Applications from space photovoltaic research

    NASA Technical Reports Server (NTRS)

    Flood, D. J.

    1986-01-01

    NASA involvement in photovoltaic energy conversion research development and applications spans over two decades of continuous progress. Solar cell research and development programs conducted by the Lewis Research Center's Photovoltaic Branch have produced a sound technology base not only for the space program, but for terrestrial applications as well. The fundamental goals which have guided the NASA photovoltaic program are to improve the efficiency and lifetime, and to reduce the mass and cost of photovoltaic energy conversion devices and arrays for use in space. The major efforts in the current Lewis program are on high efficiency, single crystal GaAs planar and concentrator cells, radiation hard InP cells, and superlattice solar cells. A brief historical perspective of accomplishments in high efficiency space solar cells will be given, and current work in all of the above categories will be described. The applicability of space cell research and technology to terrestrial photovoltaics will be discussed.

  17. High-efficiency photovoltaic cells

    DOEpatents

    Yang, H.T.; Zehr, S.W.

    1982-06-21

    High efficiency solar converters comprised of a two cell, non-lattice matched, monolithic stacked semiconductor configuration using optimum pairs of cells having bandgaps in the range 1.6 to 1.7 eV and 0.95 to 1.1 eV, and a method of fabrication thereof, are disclosed. The high band gap subcells are fabricated using metal organic chemical vapor deposition (MOCVD), liquid phase epitaxy (LPE) or molecular beam epitaxy (MBE) to produce the required AlGaAs layers of optimized composition, thickness and doping to produce high performance, heteroface homojunction devices. The low bandgap subcells are similarly fabricated from AlGa(As)Sb compositions by LPE, MBE or MOCVD. These subcells are then coupled to form a monolithic structure by an appropriate bonding technique which also forms the required transparent intercell ohmic contact (IOC) between the two subcells. Improved ohmic contacts to the high bandgap semiconductor structure can be formed by vacuum evaporating to suitable metal or semiconductor materials which react during laser annealing to form a low bandgap semiconductor which provides a low contact resistance structure.

  18. Linearity Testing of Photovoltaic Cells: Preprint

    SciTech Connect

    Emery, K.; Winter, S.; Pinegar, S.; Nalley D.

    2006-05-01

    Photovoltaic devices are rated in terms of their peak power with respect to a specific spectrum, total irradiance, and temperature. To rate photovoltaic devices, a reference detector is required whose response is linear with total irradiance. This paper describes a procedure to determine the linearity of the short-circuit current (Isc) versus the total irradiance (Etot) by illuminating a reference cell with two lamps. A device is linear if the current measured with both lamps illuminating the cell is the same as the sum of the currents with each lamp illuminating the cell. The two-lamp method is insensitive to the light spectra or spatial nonuniformity changing with irradiance. The two-lamp method is rapid, easy to implement, and does not require operator intervention to change the irradiances. The presence of room light only limits the lowest irradiance that can be evaluated. Unlike other methods, the two-lamp method does not allow the current to be corrected for nonlinear effects.

  19. Novel approaches for low-cost photovoltaic concentrator. Final report, January 1978-July 1980

    SciTech Connect

    Muller, T.; Maraschin, R.

    1982-11-01

    A concept has been developed for a photovoltaic concentrator that uses sealed beam headlight technology. The photovoltaic cell is placed at the focus of the headlamp reflector. A prototype 60 W array was designed, built, and tested. Array efficiency was approximately 6%.

  20. Entropy production in a photovoltaic cell

    NASA Astrophysics Data System (ADS)

    Ansari, Mohammad H.

    2017-05-01

    We evaluate entropy production in a photovoltaic cell that is modeled by four electronic levels resonantly coupled to thermally populated field modes at different temperatures. We use a formalism recently proposed, the so-called multiple parallel worlds, to consistently address the nonlinearity of entropy in terms of density matrix. Our result shows that entropy production is the difference between two flows: a semiclassical flow that linearly depends on occupational probabilities, and another flow that depends nonlinearly on quantum coherence and has no semiclassical analog. We show that entropy production in the cells depends on environmentally induced decoherence time and energy detuning. We characterize regimes where reversal flow of information takes place from a cold to hot bath. Interestingly, we identify a lower bound on entropy production, which sets limitations on the statistics of dissipated heat in the cells.

  1. Photovoltaic cells based on plasmonic structures

    NASA Astrophysics Data System (ADS)

    Talukder, Muhammad Anisuzzaman

    2017-05-01

    While decreasing the thickness of active layers is important in reducing the cost of solar cells, the absorption of incident light is challenging as the thickness becomes smaller than the wavelength. Metal nano-structures can be used on the top or bottom of the active layers to couple light of different plasmonic and photonic modes. Metal nano-structures can also be used as an intermediate layer within an active layer or between two active layers as in tandem solar cells. In this work, we discuss two photovoltaic cells based on plasmonic-inspired designs—one with silicon strips on the top and grooves on the silver back contact layer and the other with a periodically perforated metal layer in-between the two active layers.

  2. Photovoltaic module electrical termination design requirement study. Final report

    SciTech Connect

    Mosna, F.J. Jr.; Donlinger, J.

    1980-07-01

    Motorola Inc., in conjunction with ITT Cannon, has conducted a study to develop information to facilitate the selection of existing, commercial, electrical termination hardware for photovoltaic modules and arrays. Details of the study are presented in this volume. Module and array design parameters were investigated and recommendations were developed for use in surveying, evaluating, and comparing electrical termination hardware. Electrical termination selection criteria factors were developed and applied to nine generic termination types in each of the four application sectors. Remote, residential, intermediate and industrial. Existing terminations best suited for photovoltaic modules and arrays were identified. Cost information was developed to identify cost drivers and/or requirements which might lead to cost reductions. The general conclusion is that there is no single generic termination that is best suited for photovoltaic application, but that the appropriate termination is strongly dependent upon the module construction and its support structure as well as the specific application sector.

  3. Design & Fabrication of a High-Voltage Photovoltaic Cell

    SciTech Connect

    Felder, Jennifer; /North Carolina State U. /SLAC

    2012-09-05

    Silicon photovoltaic (PV) cells are alternative energy sources that are important in sustainable power generation. Currently, applications of PV cells are limited by the low output voltage and somewhat low efficiency of such devices. In light of this fact, this project investigates the possibility of fabricating high-voltage PV cells on float-zone silicon wafers having output voltages ranging from 50 V to 2000 V. Three designs with different geometries of diffusion layers were simulated and compared in terms of metal coverage, recombination, built-in potential, and conduction current density. One design was then chosen and optimized to be implemented in the final device design. The results of the simulation serve as a feasibility test for the design concept and provide supportive evidence of the effectiveness of silicon PV cells as high-voltage power supplies.

  4. Analysis of batteries for use in photovoltaic systems. Final report

    SciTech Connect

    Podder, A; Kapner, M

    1981-02-01

    An evaluation of 11 types of secondary batteries for energy storage in photovoltaic electric power systems is given. The evaluation was based on six specific application scenarios which were selected to represent the diverse requirements of various photovoltaic systems. Electrical load characteristics and solar insulation data were first obtained for each application scenario. A computer-based simulation program, SOLSIM, was then developed to determine optimal sizes for battery, solar array, and power conditioning systems. Projected service lives and battery costs were used to estimate life-cycle costs for each candidate battery type. The evaluation considered battery life-cycle cost, safety and health effects associated with battery operation, and reliability/maintainability. The 11 battery types were: lead-acid, nickel-zinc, nickel-iron, nickel-hydrogen, lithium-iron sulfide, calcium-iron sulfide, sodium-sulfur, zinc-chlorine, zinc-bromine, Redox, and zinc-ferricyanide. The six application scenarios were: (1) a single-family house in Denver, Colorado (photovoltaic system connected to the utility line); (2) a remote village in equatorial Africa (stand-alone power system); (3) a dairy farm in Howard County, Maryland (onsite generator for backup power); (4) a 50,000 square foot office building in Washington, DC (onsite generator backup); (5) a community in central Arizona with a population of 10,000 (battery to be used for dedicated energy storage for a utility grid-connected photovoltaic power plant); and (6) a military field telephone office with a constant 300 W load (trailer-mounted auxiliary generator backup). Recommendations for a research and development program on battery energy storage for photovoltaic applications are given, and a discussion of electrical interfacing problems for utility line-connected photovoltaic power systems is included. (WHK)

  5. Integrated photovoltaic central station conceptual designs. Final report

    SciTech Connect

    Levy, S.L.; Stoddard, L.E.

    1984-06-01

    Conceptual designs are presented for 100 MW photovoltaic central stations using fixed flat plate, one-axis tracking flat plate, two-axis tracking flat plate, and two-axis tracking high concentration collectors. Designs developed were for specific sites in the southwestern and southeastern United States, and were predicated on mid-1990 plant startup. Estimates of system performance and balance-of-system cost were developed, and cost and efficiency requirements for photovoltaic laminates (unframed modules) and concentrator collectors were derived. Results indicate that all four system types appear potentially viable in the Southwest; fixed and one-axis tracking flat plate concepts appear the best alternatives for the Southeast.

  6. Cost effective flat plate photovoltaic modules using light trapping. Final report

    SciTech Connect

    Bain, C.N.; Gordon, B.A.; Knasel, T.M.; Malinowski, R.L.

    1981-04-01

    Work in optical trapping in 'thick films' is described to form a design guide for photovoltaic engineers. A thick optical film can trap light by diffusive reflection and total internal reflection. Light can be propagated reasonably long distances compared with layer thicknesses by this technique. This makes it possible to conduct light from inter-cell and intra-cell areas now not used in photovoltaic modules onto active cell areas.

  7. Improving the photovoltaic performance of perovskite solar cells with acetate

    NASA Astrophysics Data System (ADS)

    Zhao, Qian; Li, G. R.; Song, Jian; Zhao, Yulong; Qiang, Yinghuai; Gao, X. P.

    2016-12-01

    In an all-solid-state perovskite solar cell, methylammonium lead halide film is in charge of generating photo-excited electrons, thus its quality can directly influence the final photovoltaic performance of the solar cell. This paper accentuates a very simple chemical approach to improving the quality of a perovskite film with a suitable amount of acetic acid. With introduction of acetate ions, a homogeneous, continual and hole-free perovskite film comprised of high-crystallinity grains is obtained. UV-visible spectra, steady-state and time-resolved photoluminescence (PL) spectra reveal that the obtained perovskite film under the optimized conditions shows a higher light absorption, more efficient electron transport, and faster electron extraction to the adjoining electron transport layer. The features result in the optimized perovskite film can provide an improved short-circuit current. The corresponding solar cells with a planar configuration achieves an improved power conversion efficiency of 13.80%, and the highest power conversion efficiency in the photovoltaic measurements is up to 14.71%. The results not only provide a simple approach to optimizing perovskite films but also present a novel angle of view on fabricating high-performance perovskite solar cells.

  8. Improving the photovoltaic performance of perovskite solar cells with acetate.

    PubMed

    Zhao, Qian; Li, G R; Song, Jian; Zhao, Yulong; Qiang, Yinghuai; Gao, X P

    2016-12-09

    In an all-solid-state perovskite solar cell, methylammonium lead halide film is in charge of generating photo-excited electrons, thus its quality can directly influence the final photovoltaic performance of the solar cell. This paper accentuates a very simple chemical approach to improving the quality of a perovskite film with a suitable amount of acetic acid. With introduction of acetate ions, a homogeneous, continual and hole-free perovskite film comprised of high-crystallinity grains is obtained. UV-visible spectra, steady-state and time-resolved photoluminescence (PL) spectra reveal that the obtained perovskite film under the optimized conditions shows a higher light absorption, more efficient electron transport, and faster electron extraction to the adjoining electron transport layer. The features result in the optimized perovskite film can provide an improved short-circuit current. The corresponding solar cells with a planar configuration achieves an improved power conversion efficiency of 13.80%, and the highest power conversion efficiency in the photovoltaic measurements is up to 14.71%. The results not only provide a simple approach to optimizing perovskite films but also present a novel angle of view on fabricating high-performance perovskite solar cells.

  9. Improving the photovoltaic performance of perovskite solar cells with acetate

    PubMed Central

    Zhao, Qian; Li, G. R.; Song, Jian; Zhao, Yulong; Qiang, Yinghuai; Gao, X. P.

    2016-01-01

    In an all-solid-state perovskite solar cell, methylammonium lead halide film is in charge of generating photo-excited electrons, thus its quality can directly influence the final photovoltaic performance of the solar cell. This paper accentuates a very simple chemical approach to improving the quality of a perovskite film with a suitable amount of acetic acid. With introduction of acetate ions, a homogeneous, continual and hole-free perovskite film comprised of high-crystallinity grains is obtained. UV-visible spectra, steady-state and time-resolved photoluminescence (PL) spectra reveal that the obtained perovskite film under the optimized conditions shows a higher light absorption, more efficient electron transport, and faster electron extraction to the adjoining electron transport layer. The features result in the optimized perovskite film can provide an improved short-circuit current. The corresponding solar cells with a planar configuration achieves an improved power conversion efficiency of 13.80%, and the highest power conversion efficiency in the photovoltaic measurements is up to 14.71%. The results not only provide a simple approach to optimizing perovskite films but also present a novel angle of view on fabricating high-performance perovskite solar cells. PMID:27934924

  10. Nanoplasmonics: a frontier of photovoltaic solar cells

    NASA Astrophysics Data System (ADS)

    Gu, Min; Ouyang, Zi; Jia, Baohua; Stokes, Nicholas; Chen, Xi; Fahim, Narges; Li, Xiangping; Ventura, Michael James; Shi, Zhengrong

    2012-12-01

    Nanoplasmonics recently has emerged as a new frontier of photovoltaic research. Noble metal nanostructures that can concentrate and guide light have demonstrated great capability for dramatically improving the energy conversion efficiency of both laboratory and industrial solar cells, providing an innovative pathway potentially transforming the solar industry. However, to make the nanoplasmonic technology fully appreciated by the solar industry, key challenges need to be addressed; including the detrimental absorption of metals, broadband light trapping mechanisms, cost of plasmonic nanomaterials, simple and inexpensive fabrication and integration methods of the plasmonic nanostructures, which are scalable for full size manufacture. This article reviews the recent progress of plasmonic solar cells including the fundamental mechanisms, material fabrication, theoretical modelling and emerging directions with a distinct emphasis on solutions tackling the above-mentioned challenges for industrial relevant applications.

  11. Organic photovoltaic cells with controlled polarization sensitivity

    SciTech Connect

    Awartani, Omar; O'Connor, Brendan T.; Kudenov, Michael W.

    2014-03-03

    In this study, we demonstrate linearly polarized organic photovoltaic cells with a well-controlled level of polarization sensitivity. The polarized devices were created through the application of a large uniaxial strain to the bulk heterojunction poly(3-hexylthiophene):Phenyl-C61-butyric acid methyl ester (P3HT:PCBM) film and printing the plastically deformed active layer onto a PEDOT:PSS and indium tin oxide coated glass substrate. The P3HT:PCBM layer is processed such that it is able to accommodate high strains (over 100%) without fracture. After printing the strained films, thermal annealing is used to optimize solar cell performance while maintaining polarization sensitivity. A dichroic ratio and short circuit current ratio of ≈6.1 and ≈1.6 were achieved, respectively.

  12. Terrestrial photovoltaic system analysis. Final report February-November 79

    SciTech Connect

    Imamura, M.S.; Giellis, R.; Moser, R.L.

    1980-07-01

    The purpose of this program was to evaluate the use of an actively cooled photovoltaic power system at Tinker Air Force Base, Oklahoma, which required both electrical and thermal energy. The thrust of the study was to identify a preliminary design of an actively cooled photovoltaic concentrator configuration including the necessary details of integrating it into the facility, and compare the cost of this system and that of the present energy sources. A conventional utility-connected arrangement was selected for the Tinker AFB electroplating facility mainly because of simplictiy in its implementation and availability of the inverter, which is the key component in the system. The system uses a direct energy transfer arrangement with a peak array power tracking inverter; no electrochemical storage batteries are used. The thermal energy distribution system interfaces directly with the plating tanks in the facility. The estimated initial installed cost of the combined photovoltaic/thermal system is $28 per Watt. The use of thermal energy for the plating tanks is costly ($3 per Watt) because of an extensive distribution system and use of exotic heat exchangers. One conclusion, therefore, is that an electric-only photovoltaic system is more cost effective.

  13. Inverted, semitransparent small molecule photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Xiao, Xin; Lee, Kyusang; Forrest, Stephen R.

    2015-07-01

    We demonstrate semitransparent small molecule organic photovoltaic (OPV) cells based on inverted mixed and hybrid planar-mixed heterojunction (PM-HJ) structures comprised of a neat acceptor layer located beneath the donor/acceptor mixed region. The fill factor increases from 0.53 ± 0.01 for the mixed HJ to 0.58 ± 0.01 for the PM-HJ due to reduced series resistance, whereas the internal quantum efficiency increases from an average of 75% to 85% between the wavelengths of λ = 450 nm and 550 nm. The inverted, semitransparent PM-HJ cell achieves a power conversion efficiency of PCE = 3.9% ± 0.2% under simulated AM1.5G illumination at one sun intensity with an average optical transmission of T ¯ = 51% ± 2% across the visible spectrum, corresponding to > 10% improvement compared with the mixed HJ cell. We also demonstrate an inverted semitransparent tandem cell incorporating two PM-HJ sub-cells with different absorption spectra. The tandem cell achieves a PCE = 5.3% ± 0.3% under simulated AM1.5G at one sun intensity with T ¯ = 31% ± 1% across the visible. Almost identical efficiencies are obtained for tandem cells illuminated via either the cathode or anode surfaces.

  14. Cell shunt resistance and photovoltaic module performance

    SciTech Connect

    McMahon, T.J.; Basso, T.S.; Rummel, S.R.

    1996-05-01

    Shunt resistance of cells in photovoltaic modules can affect module power output and could indicate flawed manufacturing processes and reliability problems. The authors describe a two-terminal diagnostic method to directly measure the shunt resistance of individual cells in a series-connected module non-intrusively, without deencapsulation. Peak power efficiency vs. light intensity was measured on a 12-cell, series-connected, single crystalline module having relatively high cell shunt resistances. The module was remeasured with 0.5-, 1-, and 2-ohm resistors attached across each cell to simulate shunt resistances of several emerging technologies. Peak power efficiencies decreased dramatically at lower light levels. Using the PSpice circuit simulator, the authors verified that cell shunt and series resistances can indeed be responsible for the observed peak power efficiency vs. intensity behavior. The authors discuss the effect of basic cell diode parameters, i.e., shunt resistance, series resistance, and recombination losses, on PV module performance as a function of light intensity.

  15. Fullerene derivatives as electron acceptors for organic photovoltaic cells.

    PubMed

    Mi, Dongbo; Kim, Ji-Hoon; Kim, Hee Un; Xu, Fei; Hwang, Do-Hoon

    2014-02-01

    Energy is currently one of the most important problems humankind faces. Depletion of traditional energy sources such as coal and oil results in the need to develop new ways to create, transport, and store electricity. In this regard, the sun, which can be considered as a giant nuclear fusion reactor, represents the most powerful source of energy available in our solar system. For photovoltaic cells to gain widespread acceptance as a source of clean and renewable energy, the cost per watt of solar energy must be decreased. Organic photovoltaic cells, developed in the past two decades, have potential as alternatives to traditional inorganic semiconductor photovoltaic cells, which suffer from high environmental pollution and energy consumption during production. Organic photovoltaic cells are composed of a blended film of a conjugated-polymer donor and a soluble fullerene-derivative acceptor sandwiched between a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-coated indium tin oxide positive electrode and a low-work-function metal negative electrode. Considerable research efforts aim at designing and synthesizing novel fullerene derivatives as electron acceptors with up-raised lowest unoccupied molecular orbital energy, better light-harvesting properties, higher electron mobility, and better miscibility with the polymer donor for improving the power conversion efficiency of the organic photovoltaic cells. In this paper, we systematically review novel fullerene acceptors synthesized through chemical modification for enhancing the photovoltaic performance by increasing open-circuit voltage, short-circuit current, and fill factor, which determine the performance of organic photovoltaic cells.

  16. Ultrathin optical design for organic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Man, J. X.; Luo, D. Y.; Yu, L. M.; Wang, D. K.; Liu, Z.; Lu, Z. H.

    2015-05-01

    A trilayer ultrathin-film model concept had been adapted to maximize optical absorption of organic photovoltaic cells (OPVs) with a structure of transparent-electrode/highly-absorbing active material/metal. As demonstrated, device with the structure of ITO/Lead phthalocyanine (SubPc):Buckerminster fullerene (C60) (1:4 wt%)/Al had been studied. It is found that more than 90% optical absorption can be obtained in the device with a broaden wavelength range of 480-620 nm. The calculated optical electric fields shows that the unusually high optical absorption is due to the enhanced optical interference inside the OPVs device. This work paved a new way to design the OPVs device.

  17. Series interconnected photovoltaic cells and method for making same

    DOEpatents

    Albright, S.P.; Chamberlin, R.R.; Thompson, R.A.

    1995-01-31

    A novel photovoltaic module and method for constructing the same are disclosed. The module includes a plurality of photovoltaic cells formed on a substrate and laterally separated by interconnection regions. Each cell includes a bottom electrode, a photoactive layer and a top electrode layer. Adjacent cells are connected in electrical series by way of a conductive-buffer line. The buffer line is also useful in protecting the bottom electrode against severing during downstream layer cutting processes. 11 figs.

  18. Photovoltaic subsystem optimization and design tradeoff study. Final report

    SciTech Connect

    Stolte, W.J.

    1982-03-01

    Tradeoffs and subsystem choices are examined in photovoltaic array subfield design, power-conditioning sizing and selection, roof- and ground-mounted structure installation, energy loss, operating voltage, power conditioning cost, and subfield size. Line- and self-commutated power conditioning options are analyzed to determine the most cost-effective technology in the megawatt power range. Methods for reducing field installation of flat panels and roof mounting of intermediate load centers are discussed, including the cost of retrofit installations.

  19. Understanding organic photovoltaic cells: Electrode, nanostructure, reliability, and performance

    NASA Astrophysics Data System (ADS)

    Kim, Myung-Su

    My Ph.D. research has focused on alternative renewable energy using organic semiconductors. During my study, first, I have established reliable characterization methods of organic photovoltaic devices. More specifically, less than 5% variation of power conversion efficiency of fabricated organic blend photovoltaic cells (OBPC) was achieved after optimization. The reproducibility of organic photovoltaic cell performance is one of the essential issues that must be clarified before beginning serious investigations of the application of creative and challenging ideas. Second, the relationships between fill factor (FF) and process variables have been demonstrated with series and shunt resistance, and this provided a chance to understand the electrical device behavior. In the blend layer, series resistance (Rs) and shunt resistance (Rsh) were varied by controlling the morphology of the blend layer, the regioregularity of the conjugated polymer, and the thickness of the blend layer. At the interface between the cathode including PEDOT:PSS and the blend layer, cathode conductivity was controlled by varying the structure of the cathode or adding an additive. Third, we thoroughly examined possible characterization mistakes in OPVC. One significant characterization mistake is observed when the crossbar electrode geometry of OPVC using PEDOT:PSS was fabricated and characterized with illumination which is larger than the actual device area. The hypothesis to explain this overestimation was excess photo-current generated from the cell region outside the overlapped electrode area, where PEDOT:PSS plays as anode and this was clearly supported with investigations. Finally, I incorporated a creative idea, which enhances the exciton dissociation efficiency by increasing the interface area between donor and acceptor to improve the power conversion efficiency of organic photovoltaic cells. To achieve this, nanoimprint lithography was applied for interface area increase. To clarify the

  20. Use of photovoltaics to supply some lighting at the Lake Afton Public Observatory. Final technical report

    SciTech Connect

    Unruh, H. Jr.

    1984-01-01

    We have constructed a system for supplying electrical power, using photovoltaic cells, to a collection of observing stations near the observatory. The collection of nine observing stations are on a pad about 40' x 40' located about 60' from the observatory building. The observing stations hold small telescopes for students' use and require low level lighting for reading of instrumentation. It is this low level lighting that is supplied by the photovoltaic panel using battery electrical energy storage. The photovoltaic system was prepared for practical use during the first part of last June. Since then it has been used on most clear nights. The system has worked without problems.

  1. Flasher Powered by Photovoltaic Cells and Ultracapacitors

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.; Soltis, Richard F.

    2003-01-01

    A unique safety flasher powered by photovoltaic cells and ultracapacitors has been developed. Safety flashers are used wherever there are needs to mark actually or potentially hazardous locations. Examples of such locations include construction sites, highway work sites, and locations of hazardous operations. Heretofore, safety flashers have been powered by batteries, the use of which entails several disadvantages: Batteries must be kept adequately charged, and must not be allowed to become completely discharged. Batteries have rather short cycle lives, and their internal constituents that react chemically to generate electricity deteriorate (and hence power-generating capacities decrease) over time. The performances of batteries are very poor at low temperatures, which often occur in the circumstances in which safety flashers are most needed. The disposal of batteries poses a threat to the environment. The development of the present photovoltaic/ultracapacitor- powered safety flasher, in which the ultracapacitors are used to store energy, overcomes the aforementioned disadvantages of using batteries to store energy. The ultracapacitors in this flasher are electrochemical units that have extremely high volumetric capacitances because they contain large-surface-area electrodes separated by very small gaps. Ultracapacitors have extremely long cycle lives, as compared to batteries; consequently, it will never be necessary to replace the ultracapacitors in the safety flasher. The reliability of the flasher is correspondingly increased, and the life-of-system cost and the adverse environmental effects of the flasher are correspondingly reduced. Moreover, ultracapacitors have excellent low-temperature characteristics, are maintenance-free, and provide consistent performance over time.

  2. Residential solar photovoltaic systems: Final report for the Northeast Residential Experiment Station

    SciTech Connect

    Kern, E.C. Jr.

    1986-06-01

    This report covers research and development work conducted by the MIT Energy Lab. from July 1982 through June 1986. This Energy Lab. work in the field of solar photovoltaic systems followed six years of similar work at the MIT Lincoln Lab. under the same contract with the US DOE. The final report from the Lincoln Lab. period was published by Lincoln Lab. in 1983. During the period of Energy Lab. involvement, the project focused on the refinement of residential scale, roof-mounted photovoltaic systems for application in the northeastern US. Concurrent with the conclusion of MIT`s involvement, the New England Electric Co. is building a major field test of residential photovoltaics in Gardner, Massachusetts to determine experimentally the effects of photovoltaics on electric power company operations. Using systems designs and technology developed at MIT, the long-term performance of these thirty residential systems in Gardner will provide a measure of our success.

  3. Photovoltaic module energy rating procedure. Final subcontract report

    SciTech Connect

    Whitaker, C.M.; Newmiller, J.D.

    1998-01-01

    This document describes testing and computation procedures used to generate a photovoltaic Module Energy Rating (MER). The MER consists of 10 estimates of the amount of energy a single module of a particular type (make and model) will produce in one day. Module energy values are calculated for each of five different sets of weather conditions (defined by location and date) and two load types. Because reproduction of these exact testing conditions in the field or laboratory is not feasible, limited testing and modeling procedures and assumptions are specified.

  4. Investigation of the photovoltaic cell/ thermoelectric element hybrid system performance

    NASA Astrophysics Data System (ADS)

    Cotfas, D. T.; Cotfas, P. A.; Machidon, O. M.; Ciobanu, D.

    2016-06-01

    The PV/TEG hybrid system, consisting of the photovoltaic cells and thermoelectric element, is presented in the paper. The dependence of the PV/TEG hybrid system parameters on the illumination levels and the temperature is analysed. The maxim power values of the photovoltaic cell, of the thermoelectric element and of the PV/TEG system are calculated and a comparison between them is presented and analysed. An economic analysis is also presented.

  5. Distributed generation system using wind/photovoltaic/fuel cell

    NASA Astrophysics Data System (ADS)

    Buasri, Panhathai

    This dissertation investigates the performance and the operation of a distributed generation (DG) power system using wind/photovoltaic/fuel cell (W/PV/FC). The power system consists of a 2500 W photovoltaic array subsystem, a 500 W proton exchange membrane fuel cell (PEMFC) stack subsystem, 300 W wind turbine, 500 W wind turbine, and 1500 W wind energy conversion subsystems. To extract maximum power from the PV, a maximum power point tracker was designed and fabricated. A 4 kW single phase inverter was used to convert the DC voltage to AC voltage; also a 44 kWh battery bank was used to store energy and prevent fluctuation of the power output of the DG system. To connect the fuel cell to the batteries, a DC/DC controller was designed and fabricated. To monitor and study the performance of the DG system under variable conditions, a data acquisition system was designed and installed. The fuel cell subsystem performance was evaluated under standalone operation using a variable resistance and under interactive mode, connected to the batteries. The manufacturing data and the experimental data were used to develop an electrical circuit model to the fuel cell. Furthermore, harmonic analysis of the DG system was investigated. For an inverter, the AC voltage delivered to the grid changed depending on the time, load, and electronic equipment that was connected. The quality of the DG system was evaluated by investigating the harmonics generated by the power electronics converters. Finally, each individual subsystem of the DG system was modeled using the neuro-fuzzy approach. The model was used to predict the performance of the DG system under variable conditions, such as passing clouds and wind gust conditions. The steady-state behaviors of the model were validated by the experimental results under different operating conditions.

  6. 64 kW concentrator Photovoltaics Application Test Center. Volume. Final report

    SciTech Connect

    Jardine, D.M.; Jones, D.W.

    1980-06-01

    Kaman Sciences Corporation has designed a 64 kW Concentrating Photovoltaic Applications Test Center (APTEC). The APTEC employs a combined concentrating photovoltaic array in a total energy system application for load sharing the electric and thermal demands of a large computer center with the interfaced electric and natural gas utility. The photovoltaic array is composed of two-axis tracking heliostats of Fresnel lens concentrating, silicon solar cell modules. The modules are cooled with a fluid which transfers heat to a ground coupled heat sink/storage unit for subsequent use in meeting the computer center's thermal load demand. The combined photovoltaic power system shares basic components - a power conditioning unit, batteries and thermal conditioning equipment - with the electric and natural gas utility service, improving the computer center's operating availability time and displacing a portion of the fossil fuel required to power the computer center with solar energy. The detailed system design is reported.

  7. Final Technical Report - Photovoltaics for You (PV4You) Program

    SciTech Connect

    Weissman, J. M.; Sherwood, L.; Pulaski, J.; Cook, C.; Kalland, S.; Haynes, J.

    2005-08-14

    In September 2000, the Interstate Renewable Energy Council (IREC) began its 5-year work on contract # DE-FGO3-00SF22116, the Photovoltaics for You (PV4You) Project. The objective was to develop and distribute information on photovoltaics and to educate key stakeholder groups including state government agencies, local government offices, consumer representative agencies, school officials and students, and Million Solar Roofs Partnerships. In addition, the project was to identify barriers to the deployment of photovoltaics and implement strategies to overcome them. Information dissemination and education was accomplished by publishing newsletters; creating a base of information, guides, and models on the www.irecusa.org and the www.millionsolarroofs.org web sites; convening workshops and seminars; engaging multiple stakeholders; and widening the solar network to include new consumers and decision makers. Two major web sites were maintained throughout the project cycle. The www.irecusa.org web site housed dedicated pages for Connecting to the Grid, Schools Going Solar, Community Outreach, and Certification & Training. The www.millionsolarroofs.org web site was created to serve the MSR Partnerships with news, interviews, key documents, and resource material. Through the course of this grant, the Interstate Renewable Energy Council has been supporting the Department of Energy's solar energy program goals by providing the Department with expertise services for their network of city, state, and community stakeholders. IREC has been the leading force at the state and federal levels regarding net metering and interconnection policy for photovoltaic systems. The principal goal and benefit of the interconnection and net metering work is to lower both barriers and cost for the installation of PV. IREC typically plays a leadership role among small generator stakeholders and has come to be relied upon for its expertise by industry and regulators. IREC also took a leadership

  8. Final Technical Report for Photovoltaic Power Electronics Research Initiative (PERI)

    SciTech Connect

    Amirahmadi, Ahmadreza; Jordan, Charlie; batarseh, Issa

    2015-08-31

    The Power Electronics team at the University of Central Florida (UCF) has developed a novel three-phase micro-inverter for photovoltaic (PV) distributed applications. Based on a new advanced topology and control methodology, the developed inverter is small in size, and achieved DoE targeted power density, cost and efficiency specifications. Today’s inverters are widely used in PV based energy harvesting systems, but are based on single-phase design with limited application to large installations. These micro-inverters have been shown to have advantageous over their string inverter counterparts in both grid-tied PV energy harvesting and standalone micro-grid systems with energy storage. Some of these are simplified installation, no high voltage DC wiring, no single point of failure and improved energy harvesting. Several patents have been issued and this new solar conversion technology has been licensed to the private sector.

  9. Engineering and economic evaluation of central-station photovoltaic power plants. Final report

    SciTech Connect

    Stolte, W.J.

    1992-12-01

    This report describes the conceptual design, design optimization, and estimated cost and performance of three 50 MW photovoltaic power plants. The first design uses Fresnel lens/glass silo modules mounted on two-axis tracking arrays. The second design has all of the cells mounted on a central receiver on top of a single tower, with heliostats concentrating sunlight onto the receiver. Both designs are based on a similar advanced back-contact silicon concentrator cell developed under EPRI sponsorship. The third design uses thin-film copper indium diselenide flat-plate modules mounted on fixed-tilt array structures. The design and manufacture of the photovoltaic cells and modules are described, along with selection of the photovoltaic technologies, generating and cell manufacturing plant sites. Power system simulation and revenue requirement analyses are included for all of the plant designs.

  10. Final Report: Vapor Transport Deposition for Thin Film III-V Photovoltaics

    SciTech Connect

    Boettcher, Shannon; Greenaway, Ann; Boucher, Jason; Aloni, Shaul

    2016-02-10

    ternary GaAsxP1-x and In0.5Ga0.5P alloys, with composition set by the ratio of GaAs/GaP or InP/GaP mixed as the source powder. GaAs0.3P0.7 has the appropriate bandgap to serve as a top cell on Si and In0.5Ga0.5P is near the composition used as a surface passivation layer on GaAs pn junction photovoltaics. In the final task we demonstrated III-V selective area epitaxy using CSVT as a first step toward the growth of III-V micro- or nanostructures for an integrated tandem solar cell on Si. We also found that direct epitaxial growth on Si appears to be impossible in the current H2O-CSVT reactor design, likely due to the formation of SiOx. This work sets the stage for targeted development of an improved CSVT process and for the scale up of the proof-of-concept work from a research to manufacturing-relevant platform. Replacing H2O as a transport agent with HCl would provide the ability to deposit directly on Si by avoiding oxide formation and to allow for the deposition of Al-containing alloys that would otherwise oxidize. Improved engineering design and implementation of an in-line multi-station CSVT would allow for direct deposition of device structures in a single system.

  11. 77 FR 37877 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-25

    ... International Trade Administration Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules... determination in the antidumping duty investigation of crystalline silicon photovoltaic cells, whether or not assembled into modules (``solar cells''), from the People's Republic of China (``PRC''). The...

  12. Perovskite photovoltaics: a high-efficiency newcomer to the solar cell family.

    PubMed

    Wang, Baohua; Xiao, Xudong; Chen, Tao

    2014-11-07

    Organometal trihalide perovskite-based light absorbers have attracted great attention due to their excellent photovoltaic properties. The swift developments in the device fabrication techniques have led to the power conversion efficiencies exceeding 17%. In this minireview, we will present the typical characteristics of the materials and device structures, followed by analysing updated understandings on the operational principles of the devices. We will also point out the outstanding issues regarding the materials and devices. Finally, as a high-efficiency newcomer to the solar cell family, the potential impact on the relevant photovoltaics will be discussed.

  13. Perovskite photovoltaics: a high-efficiency newcomer to the solar cell family

    NASA Astrophysics Data System (ADS)

    Wang, Baohua; Xiao, Xudong; Chen, Tao

    2014-10-01

    Organometal trihalide perovskite-based light absorbers have attracted great attention due to their excellent photovoltaic properties. The swift developments in the device fabrication techniques have led to the power conversion efficiencies exceeding 17%. In this minireview, we will present the typical characteristics of the materials and device structures, followed by analysing updated understandings on the operational principles of the devices. We will also point out the outstanding issues regarding the materials and devices. Finally, as a high-efficiency newcomer to the solar cell family, the potential impact on the relevant photovoltaics will be discussed.

  14. Novel High Efficient Organic Photovoltaic Materials: Final Summary of Research

    NASA Technical Reports Server (NTRS)

    Sun, Sam

    2002-01-01

    The objectives and goals of this project were to investigate and develop high efficient, lightweight, and cost effective materials for potential photovoltaic applications, such as solar energy conversion or photo detector devices. Specifically, as described in the original project proposal, the target material to be developed was a block copolymer system containing an electron donating (or p-type) conjugated polymer block coupled to an electron withdrawing (or n-type) conjugated polymer block through a non-conjugated bridge unit. Due to several special requirements of the targeted block copolymer systems, such as electron donating and withdrawing substituents, conjugated block structures, processing requirement, stability requirement, size controllability, phase separation and self ordering requirement, etc., many traditional or commonly used block copolymer synthetic schemes are not suitable for this system. Therefore, the investigation and development of applicable and effective synthetic protocols became the most critical and challenging part of this project. During the entire project period, and despite the lack of a proposed synthetic polymer postdoctoral research associate due to severe shortage of qualified personnel in the field, several important accomplishments were achieved in this project and are briefly listed and elaborated. A more detailed research and experimental data is listed in the Appendix.

  15. Electric vehicle/photovoltaic test and evaluation program. Final report

    SciTech Connect

    1997-06-01

    The University of South Florida (USF) in collaboration with Florida utilities and other organizations have executed a research and development program for the test and evaluation of Electric Vehicles. Its activity as one of 13 US Department of Energy (DOE) Electric Vehicle Test Site Operators was funded by DOE and the Florida Energy Office (FEO). The purpose of this program was to determine the efficiency of electric vehicles under commuter and fleet conditions in Florida. An additional feature of this program was the development of a utility interconnected photovoltaic (PV) system for charging electric vehicles with solar energy. USF developed an effective and economical automated on board Mobile Data Acquisition System (MDAS) that records vehicle operating data with minimum operator interface. Computer programs were written by the USF team to achieve processing and analysis of the vehicles` MDAS data, again minimizing human involvement, human effort and human error. A large number of passenger cars, vans and pickup trucks were studied. Procedures for monitoring them were developed to a point where the equipment is commercially available and its operation has become routine. The nations first PV solar powered electric vehicle charging station and test facility was designed, developed and put into operation under this program. The charging station is capable of direct DC-DC (PV to battery) or AC-DC (power grid to battery) charging and it routes unused PV power to the University`s power grid for other use. The DC-DC charging system is more efficient, more dependable and safer than DC-AC-DC and traditional methods of DC-DC charging. A fortuitous correlation was observed between battery charging demand and solar power availability in commuter application of electric vehicles.

  16. Series interconnected photovoltaic cells and method for making same

    DOEpatents

    Albright, Scot P.; Chamberlin, Rhodes R.; Thompson, Roger A.

    1995-01-01

    A novel photovoltaic module (10) and method for constructing the same are disclosed. The module (10) includes a plurality of photovoltaic cells (12) formed on a substrate (14) and laterally separated by interconnection regions (15). Each cell (12) includes a bottom electrode (16), a photoactive layer (18) and a top electrode layer (20). Adjacent cells (12) are connected in electrical series by way of a conductive-buffer line (22). The buffer line (22) is also useful in protecting the bottom electrode (16) against severing during downstream layer cutting processes.

  17. Laminated photovoltaic modules using back-contact solar cells

    DOEpatents

    Gee, James M.; Garrett, Stephen E.; Morgan, William P.; Worobey, Walter

    1999-09-14

    Photovoltaic modules which comprise back-contact solar cells, such as back-contact crystalline silicon solar cells, positioned atop electrically conductive circuit elements affixed to a planar support so that a circuit capable of generating electric power is created. The modules are encapsulated using encapsulant materials such as EVA which are commonly used in photovoltaic module manufacture. The module designs allow multiple cells to be electrically connected in a single encapsulation step rather than by sequential soldering which characterizes the currently used commercial practices.

  18. 76 FR 66748 - Crystalline Silicon Photovoltaic Cells and Modules From China; Institution of Antidumping and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-27

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Crystalline Silicon Photovoltaic Cells and Modules From China; Institution of Antidumping and... from China of crystalline silicon photovoltaic cells and modules, provided for in subheadings...

  19. Solar Photovoltaic Cell/Module Shipments Report

    EIA Publications

    2016-01-01

    Summary data for the photovoltaic industry in the United States. Data includes manufacturing, imports, and exports of modules in the United States and its territories. Summary data include volumes in peak kilowatts and average prices. Where possible, imports and exports are listed by country, and shipments to the United States are listed by state.

  20. Solar Photovoltaic Cell/Module Shipments Report

    EIA Publications

    2017-01-01

    Summary data for the photovoltaic industry in the United States. Data includes manufacturing, imports, and exports of modules in the United States and its territories. Summary data include volumes in peak kilowatts and average prices. Where possible, imports and exports are listed by country, and shipments to the United States are listed by state.

  1. Photovoltaic cells and photodetectors made with semiconductor polymers: recent progress

    NASA Astrophysics Data System (ADS)

    Yu, Gang; Srdanov, Gordana; Wang, Hailiang; Cao, Yong; Heeger, Alan J.

    2000-05-01

    In this presentation, we discuss recent progress on polymer photovoltaic cells and polymer photodetectors. By improving the fill-factor of polymer photovoltaic cells, the energy conversion efficiency was improved significantly to over 4 percent. Such high efficiency polymer photovoltaic cells are promising for many applications including e-papers, e-books and smart-windows. Polymer photodetectors with similar device configuration show high photosensitivity, low dark current, large dynamic range, linear intensity dependence, low noise level and fast response time. These parameters are comparable to or even better than their inorganic counterparts. The advantages of low manufacturing cost, large detection area, and easy hybridization and integration with other electronic or optical components make them promising for a variety of applications including chemical/biomedical analysis, full-color digital image sensing and high energy radiation detection.

  2. Microscopic Perspective on Photovoltaic Reciprocity in Ultrathin Solar Cells

    NASA Astrophysics Data System (ADS)

    Aeberhard, Urs; Rau, Uwe

    2017-06-01

    The photovoltaic reciprocity theory relates the electroluminescence spectrum of a solar cell under applied bias to the external photovoltaic quantum efficiency of the device as measured at short circuit conditions. Its derivation is based on detailed balance relations between local absorption and emission rates in optically isotropic media with nondegenerate quasiequilibrium carrier distributions. In many cases, the dependence of density and spatial variation of electronic and optical device states on the point of operation is modest and the reciprocity relation holds. In nanostructure-based photovoltaic devices exploiting confined modes, however, the underlying assumptions are no longer justifiable. In the case of ultrathin absorber solar cells, the modification of the electronic structure with applied bias is significant due to the large variation of the built-in field. Straightforward use of the external quantum efficiency as measured at short circuit conditions in the photovoltaic reciprocity theory thus fails to reproduce the electroluminescence spectrum at large forward bias voltage. This failure is demonstrated here by numerical simulation of both spectral quantities at normal incidence and emission for an ultrathin GaAs p -i -n solar cell using an advanced quantum kinetic formalism based on nonequilibrium Green's functions of coupled photons and charge carriers. While coinciding with the semiclassical relations under the conditions of their validity, the theory provides a consistent microscopic relationship between absorption, emission, and charge carrier transport in photovoltaic devices at arbitrary operating conditions and for any shape of optical and electronic density of states.

  3. Microscopic Perspective on Photovoltaic Reciprocity in Ultrathin Solar Cells.

    PubMed

    Aeberhard, Urs; Rau, Uwe

    2017-06-16

    The photovoltaic reciprocity theory relates the electroluminescence spectrum of a solar cell under applied bias to the external photovoltaic quantum efficiency of the device as measured at short circuit conditions. Its derivation is based on detailed balance relations between local absorption and emission rates in optically isotropic media with nondegenerate quasiequilibrium carrier distributions. In many cases, the dependence of density and spatial variation of electronic and optical device states on the point of operation is modest and the reciprocity relation holds. In nanostructure-based photovoltaic devices exploiting confined modes, however, the underlying assumptions are no longer justifiable. In the case of ultrathin absorber solar cells, the modification of the electronic structure with applied bias is significant due to the large variation of the built-in field. Straightforward use of the external quantum efficiency as measured at short circuit conditions in the photovoltaic reciprocity theory thus fails to reproduce the electroluminescence spectrum at large forward bias voltage. This failure is demonstrated here by numerical simulation of both spectral quantities at normal incidence and emission for an ultrathin GaAs p-i-n solar cell using an advanced quantum kinetic formalism based on nonequilibrium Green's functions of coupled photons and charge carriers. While coinciding with the semiclassical relations under the conditions of their validity, the theory provides a consistent microscopic relationship between absorption, emission, and charge carrier transport in photovoltaic devices at arbitrary operating conditions and for any shape of optical and electronic density of states.

  4. 77 FR 72884 - Crystalline Silicon Photovoltaic Cells and Modules From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-06

    ... COMMISSION Crystalline Silicon Photovoltaic Cells and Modules From China Determinations On the basis of the... reason of imports of crystalline silicon photovoltaic cells and modules from China, provided for in... silicon photovoltaic cells and modules from China. Chairman Irving A. Williamson and Commissioner Dean...

  5. 77 FR 10478 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-22

    ... International Trade Administration Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules... crystalline silicon photovoltaic cells, whether or not assembled into modules, from the People's Republic of..., 2012, which the Department granted.\\2\\ \\1\\ See Crystalline Silicon Photovoltaic Cells, Whether or...

  6. 76 FR 78313 - Crystalline Silicon Photovoltaic Cells and Modules From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-16

    ... COMMISSION Crystalline Silicon Photovoltaic Cells and Modules From China Determinations On the basis of the... is materially injured by reason of imports from China of crystalline silicon photovoltaic cells and... crystalline silicon photovoltaic cells and modules from China. Accordingly, effective October 19, 2011,...

  7. 76 FR 81914 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-29

    ... International Trade Administration Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules... photovoltaic cells, whether or not assembled into modules, from the People's Republic of China.\\1\\ Currently... Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's Republic of China: Initiation...

  8. 77 FR 4764 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-31

    ... International Trade Administration Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules... duty investigation of crystalline silicon photovoltaic cells, whether or not assembled into modules... Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's Republic of China: Postponement...

  9. Tandem photovoltaic solar cells and increased solar energy conversion efficiency

    NASA Technical Reports Server (NTRS)

    Loferski, J. J.

    1976-01-01

    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.

  10. Tandem photovoltaic solar cells and increased solar energy conversion efficiency

    NASA Technical Reports Server (NTRS)

    Loferski, J. J.

    1976-01-01

    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.

  11. SEM analysis as a diagnostic tool for photovoltaic cell degradation

    NASA Astrophysics Data System (ADS)

    Osayemwenre, Gilbert; Meyer, E. L.

    2013-04-01

    The importance of scanning electron microscopy (SEM) analysis as a diagnostic tool for analyzing the degradation of a polycrystalline Photovoltaic cell has been studied. The main aim of this study is to characterize the surface morphology of hot spot regions (degraded) cells in photovoltaic solar cells. In recent years, production of hetero and multi-junction solar cells has experience tremendous growth as compared to conventional silicon (Si) solar cells. Thin film photovoltaic solar cells generally are more prone to exhibiting defects and associated degradation modes. To improve the lifetime of these cells and modules, it is imperative to fully understand the cause and effect of defects and degradation modes. The objective of this paper is to diagnose the observed degradation in polycrystalline silicon cells, using scanning electron microscopy (SEM). In this study poly-Si cells were characterize before and after reverse biasing, the reverse biasing was done to evaluate the cells' susceptibility to leakage currents and hotspots formation. After reverse biasing, some cells were found to exhibit hotspots as confirmed by infrared thermography. The surface morphology of these hotspots re

  12. Photovoltaic device with specially arranged luminescent collector and cell

    SciTech Connect

    Yerkes, J. W.

    1981-02-17

    A photovoltaic device for collecting solar radiation and converting it to electrical energy has a luminescent collector shaped in a way that maintains collecting area efficiency while allowing the photovoltaic cell to be entirely shadowed or protected from the direct rays of solar energy. The shape of the luminescent collector is also especially suited to air cooling and to placement of insulation between the collector surface and the cell. The collector has a first extension which receives and absorbs the light energy and at least one side extension which extends away from the sun collecting part of the collector. The side extension or extensions conduct the collected light energy to the protected cell or cells. For example, the luminescent collector may have an inverted u-shape or l-shape. A photovoltaic cell is coupled to the side extension, preferably at the end surface of the side extension. Each cell is placed entirely away from surfaces directly heated by the rays of the sun and is entirely shadowed from radiant heating by a part of the photovoltaic device. The underside of the collector may be shaped to form a channel. The channel may be used for air cooling, thermal insulation, or a combination of air cooling and thermal insulation of the sun-receiving part of the collector. The upper outer surface of the collector may be protected by a protective, radiation transmissive cover. Light emissive areas of the edge and lower surfaces of the collector not covered by photovoltaic cells may also be covered by a reflective material.

  13. Superlattice doped layers for amorphous silicon photovoltaic cells

    DOEpatents

    Arya, Rajeewa R.

    1988-01-12

    Superlattice doped layers for amorphous silicon photovoltaic cells comprise a plurality of first and second lattices of amorphous silicon alternatingly formed on one another. Each of the first lattices has a first optical bandgap and each of the second lattices has a second optical bandgap different from the first optical bandgap. A method of fabricating the superlattice doped layers also is disclosed.

  14. Compatibility of Fresnel lenses and photovoltaic cells in concentrator modules

    SciTech Connect

    Stillwell, C.B.; Shafer, B.D.

    1981-01-01

    Test data are used to compare, for point focus photovoltaic concentrator modules, the relationship between Fresnel lens and module efficiency. The data shows that lenses designed for maximum optical efficiency may not produce the maximum module efficiency. Lenses designed with consideration for the photon flux distribution on the solar cell may improve module efficiency possibly at some loss in lens optical performance.

  15. Back contact to film silicon on metal for photovoltaic cells

    DOEpatents

    Branz, Howard M.; Teplin, Charles; Stradins, Pauls

    2013-06-18

    A crystal oriented metal back contact for solar cells is disclosed herein. In one embodiment, a photovoltaic device and methods for making the photovoltaic device are disclosed. The photovoltaic device includes a metal substrate with a crystalline orientation and a heteroepitaxial crystal silicon layer having the same crystal orientation of the metal substrate. A heteroepitaxial buffer layer having the crystal orientation of the metal substrate is positioned between the substrate and the crystal silicon layer to reduce diffusion of metal from the metal foil into the crystal silicon layer and provide chemical compatibility with the heteroepitaxial crystal silicon layer. Additionally, the buffer layer includes one or more electrically conductive pathways to electrically couple the crystal silicon layer and the metal substrate.

  16. Byproduct mineral commodities used for the production of photovoltaic cells

    USGS Publications Warehouse

    Bleiwas, Donald I.

    2010-01-01

    Rising fossil fuel costs, environmental concerns relating to global climate change, and Government policy to signifcantly increase our Nation's energy independence have placed greater emphasis on the generation of electricity from renewable sources, such as the Sun (light and heat), water, and wind, which for all intents and purposes are inexhaustible resources. Although the total amount of electricity generated from the direct conversion of sunlight through photovoltaic cells is relatively small compared with that from other forms of renewable energy, the rate of growth in the sector is signifcant. The total value of energy of photovoltaic cells produced worldwide increased to nearly 7 gigawatts (GW) in 2008 from 45 megawatts (MW) in 1990, a compound annual growth rate of about 30 percent. In the United States, manufacturing of photovoltaic cells has grown exponentially to about 480 MW in 2008, accounting for 6 percent of world production, from less than 10 MW of photovoltaic capacity in 1990 (Benner, 2007; U.S. Department of Energy, Energy Information Administration, 2010), a compound annual growth rate of approxi-mately 23 percent. A production capacity of 1 GW of electricity [or 8,760 gigawatthours1 (GWh)] is equivalent to the annual electricity requirements for roughly 800,000 average households in the United States (U.S. Department of Energy, Energy Information Administration, 2010). This estimate does not include losses of electricity, such as during transmission through power lines.

  17. Nanostructured photovoltaic devices for next generation solar cell

    NASA Astrophysics Data System (ADS)

    Kim, Sung Jin

    2008-10-01

    dissociation and charge transport, novel NQDs with functionalized ligands were developed. This research included the development of an approach to produce predefined patterns of quantum dots and multipod nanocrystals. The technique used optical lithography for direct writing of device structures for optoelectronic and electronic devices as well as the ability to change the ligand properties by using heat treatment. CdSe, CdTe, and PbSe nanocrystals were all functionalized by the incorporation of the functional ligand t-butoxycarbonyl (t-BOC). The ability to modify ligands of spin-casted nanocrystal layers by heating enables the fabrication of multi-layered structures. Moreover, the direct photopatterning of nanocrystal device structures was facilitated by the incorporation of a photo acid generator with the t-BOC functionalized nanocrystals. Finally, three different approaches that were recently developed to use t-BOC protected NQDs for photovoltaic devices will be discussed. The three types of devices that were developed include: (1) a multi-layered NQD all inorganic heterojunction photovoltaic devices; (2) a Schottky junction solar cell using a metal electrode on a NQD thin film; and (3) a hybrid (NQD/Polymer) bulk heterojunction device. Detailed characterization of these devices demonstrated that the t-BOC protected NQDs can be used to boost device performance (as compared to devices made from NQD with other ligands). This result provides significant advantages for realizing complicated device structures in the future.

  18. A critical test of organic P-N photovoltaic cells

    SciTech Connect

    Bird, G.R.

    1996-09-01

    We present an urgent view of the field of organic solid state photovoltaic cells. This is a proper time to select the most promising materials from the Electrophotographic Industry, materials long tried in terms of stability, high quantum yield of charge carriers, but set apart by unusually high quantum yields at low applied fields. Our experience with the candidate dyes has covered new tests for identifiable impurities and removal of these impurities by verifiable methods. A new method of purification, reactive train sublimation, has been developed for DNT, one of the simplest of the outstanding perylene dyes, and the method seems applicable to some of the other promising perylene derivatives. It removes the offending impurity by converting it into the desired pure product. The role of water of hydration in the {open_quotes}wine cellar effect{close_quotes}, the slowly rising performance of newly made phthalocyanine containing cells has been analyzed. Under the concept of feasibility testing before a final refinement for practicality of materials and production methods, the hydration can be controlled for high level testing. At the same time, efforts go forward to eliminate the need. At least one of the best phthalocyanine components, X-H{sub 2}Pc, does not require water for peak performance. Finally, we have attacked BBIP (bis-benzimidazole perylene) one of the best and most enigmatic of the near infrared sensors. It has long been known and used as a mixture of synthetic isomers, and we hypothesize that either of these would be better than the uncontrolled mixture. A partial success in the form of isolating highly enriched crystals for an X-ray structure of the trans-molecule, is first presented here. A simple optical analysis method has been developed to follow enrichment procedures. For all of its difficult history, this material seems closest to a state of readiness for critical feasibility testing.

  19. Development of a 160X crossed lens photovoltaic concentrator. Final report

    SciTech Connect

    McDanal, A.J.

    1986-03-01

    A new concentrator concept, the crossed lens solar photovoltaic concentrator, is described. The innovative concentrator cross-couples simple plano-cylindrical lenses with a linear Fresnel lens to achieve a geometric concentration ratio of 160X. The linear Fresnel lens provides lateral focussing of the incident sunlight while the plano-cylindrical lenses provide longitudinal focussing. The combined lateral/longitudinal focussing results in a series of focal spots on the photovoltaic receiver rather than a continuous focal line. An initial prototype module was fabricated and performance tested. The demonstrated peak electrical efficiency is 15.1% at 28/sup 0/C cell temperature. Incorporation of recently developed design improvements (a proprietary prismaic cell cover and a lens anti-reflection coating) indicates that a 20% module efficiency is achievable.

  20. Quantifying Solar Cell Cracks in Photovoltaic Modules by Electroluminescence Imaging

    SciTech Connect

    Spataru, Sergiu; Hacke, Peter; Sera, Dezso; Glick, Stephen; Kerekes, Tamas; Teodorescu, Remus

    2015-06-14

    This article proposes a method for quantifying the percentage of partially and totally disconnected solar cell cracks by analyzing electroluminescence images of the photovoltaic module taken under high- and low-current forward bias. The method is based on the analysis of the module's electroluminescence intensity distribution, applied at module and cell level. These concepts are demonstrated on a crystalline silicon photovoltaic module that was subjected to several rounds of mechanical loading and humidity-freeze cycling, causing increasing levels of solar cell cracks. The proposed method can be used as a diagnostic tool to rate cell damage or quality of modules after transportation. Moreover, the method can be automated and used in quality control for module manufacturers, installers, or as a diagnostic tool by plant operators and diagnostic service providers.

  1. All-Weather Solar Cells: A Rising Photovoltaic Revolution.

    PubMed

    Tang, Qunwei

    2017-06-16

    Solar cells have been considered as one of the foremost solutions to energy and environmental problems because of clean, high efficiency, cost-effective, and inexhaustible features. The historical development and state-of-the-art solar cells mainly focus on elevating photoelectric conversion efficiency upon direct sunlight illumination. It is still a challenging problem to realize persistent high-efficiency power generation in rainy, foggy, haze, and dark-light conditions (night). The physical proof-of-concept for all-weather solar cells opens a door for an upcoming photovoltaic revolution. Our group has been exploring constructive routes to build all-weather solar cells so that these advanced photovoltaic technologies can be an indication for global solar industry in bringing down the cost of energy harvesting. How the all-weather solar cells are built without reducing photo performances and why such architectures can realize electricity outputs with no visible-light are discussed. Potential pathways and opportunities to enrich all-weather solar cell families are envisaged. The aspects discussed here may enable researchers to develop undiscovered abilities and to explore wide applications of advanced photovoltaics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Photovoltaic manufacturing technology, Phase 1. Final technical report, 1 May 1991--10 May 1991

    SciTech Connect

    Not Available

    1992-10-01

    This report describes subcontracted research by the Chronar Corporation, prepared by Advanced Photovoltaic Systems, Inc. (APS) for Phase 1 of the Photovoltaic Manufacturing Technology Development project. Amorphous silicon is chosen as the PV technology that Chronar Corporation and APS believe offers the greatest potential for manufacturing improvements, which, in turn, will result in significant cost reductions and performance improvements in photovoltaic products. The APS ``Eureka`` facility was chosen as the manufacturing system that can offer the possibility of achieving these production enhancements. The relationship of the ``Eureka`` facility to Chronar`s ``batch`` plants is discussed. Five key areas are also identified that could meet the objectives of manufacturing potential that could lead to improved performance, reduced manufacturing costs, and significantly increased production. The projected long-term potential benefits of these areas are discussed, as well as problems that may impede the achievement of the hoped-for developments. A significant number of the problems discussed are of a generic nature and could be of general interest to the industry. The final section of this document addresses the cost and time estimates for achieving the solutions to the problems discussed earlier. Emphasis is placed on the number, type, and cost of the human resources required for the project.

  3. Photoelectrolysis of water in semiconductor septum electrochemical photovoltaic cells

    SciTech Connect

    Tien, H.T.; Chen, J.W. )

    1992-01-01

    Producing hydrogen from water has been the dream of generations of energy-conscious scientists and engineers. That dream may at last be realized in the semiconductor septum electrochemical photovoltaic (SC-SEP) cell, which is modeled after nature's photosynthetic thylakoid membrane. The novel SC-SEP cell arose from studies of pigmented bilayer lipid membranes. The cell is easy to construct and simple to operate. It appears to offer a practical approach to the photochemical conversion and storage of solar energy. This report describes how hydrogen is produced from artificial sea water when an SC-SEP cell is irradiated by the visible light of the solar spectrum.

  4. Effect of molecular electrical doping on polyfuran based photovoltaic cells

    SciTech Connect

    Yu, Shuwen; Opitz, Andreas; Salzmann, Ingo; Frisch, Johannes; Cohen, Erez; Bendikov, Michael; Koch, Norbert

    2015-05-18

    The electronic, optical, and morphological properties of molecularly p-doped polyfuran (PF) films were investigated over a wide range of doping ratio in order to explore the impact of doping in photovoltaic applications. We find evidence for integer-charge transfer between PF and the prototypical molecular p-dopant tetrafluoro-tetracyanoquinodimethane (F4TCNQ) and employed the doped polymer in bilayer organic solar cells using fullerene as acceptor. The conductivity increase in the PF films at dopant loadings ≤2% significantly enhances the short-circuit current of photovoltaic devices. For higher doping ratios, however, F4TCNQ is found to precipitate at the heterojunction between the doped donor polymer and the fullerene acceptor. Ultraviolet photoelectron spectroscopy reveals that its presence acts beneficial to the energy-level alignment by doubling the open-circuit voltage of solar cells from 0.2 V to ca. 0.4 V, as compared to pristine PF.

  5. Commercial production of thin-film CdTe photovoltaic modules. Final report

    SciTech Connect

    Brog, T. K.

    1997-10-01

    This annual report describes gains made in the manufacturing process for CdS/CdTe thin film photovoltaics deposited on soda/lime glass. The company was forced to restructure following its inability to manufacture modules which did not suffer extensive degradation. Following this the company restructured its manufacturing process line through a better understanding of the materials and materials processing issues. This led to major improvements in the production of cells, both in terms of the effective yield off the manufacturing line, but also in device stability and cell efficiency.

  6. Photovoltaic Performance of Perovskite Solar Cells with Different Grain Sizes.

    PubMed

    Kim, Hyung Do; Ohkita, Hideo; Benten, Hiroaki; Ito, Shinzaburo

    2016-02-03

    Perovskite solar cells exhibit improved photovoltaic parameters with increasing perovskite grain size. The larger photocurrent is due to the enhanced absorption efficiency for thicker perovskite layers. The larger open-circuit voltage (VOC ) is ascribed to the reduced trap-assisted recombination for the larger grains. As a result, the power conversion efficiency exceeds 19% at best. Further improvement in VOC would be possible if the trap density were reduced.

  7. Simple characterization of electronic processes in perovskite photovoltaic cells

    SciTech Connect

    Miyano, Kenjiro Yanagida, Masatoshi; Tripathi, Neeti; Shirai, Yasuhiro

    2015-03-02

    Electronic properties of perovskite lead-halide photovoltaic cells have been studied. The dc current/voltage characteristics were found to be well fitted by a standard diode equation under optical excitation and in the dark, while the impedance spectroscopy revealed a pronounced slow process under light illumination, which is absent in the dark. A simple model is proposed, which can explain all aspects of the observed behavior quantitatively and consistently.

  8. Analysis of Electrical Characteristics of Thin Film Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Kasick, Michael P.

    2004-01-01

    Solar energy is the most abundant form of energy in many terrestrial and extraterrestrial environments. Often in extraterrestrial environments sunlight is the only readily available form of energy. Thus the ability to efficiently harness solar energy is one of the ultimate goals in the design of space power systems. The essential component that converts solar energy into electrical energy in a solar energy based power system is the photovoltaic cell. Traditionally, photovoltaic cells are based on a single crystal silicon absorber. While silicon is a well understood technology and yields high efficiency, there are inherent disadvantages to using single crystal materials. The requirements of weight, large planar surfaces, and high manufacturing costs make large silicon cells prohibitively expensive for use in certain applications. Because of silicon s disadvantages, there is considerable ongoing research into alternative photovoltaic technologies. In particular, thin film photovoltaic technologies exhibit a promising future in space power systems. While they are less mature than silicon, the better radiation hardness, reduced weight, ease of manufacturing, low material cost, and the ability to use virtually any exposed surface as a substrate makes thin film technologies very attractive for space applications. The research group lead by Dr. Hepp has spent several years researching copper indium disulfide as an absorber material for use in thin film photovoltaic cells. While the group has succeeded in developing a single source precursor for CuInS2 as well as a unique method of aerosol assisted chemical vapor deposition, the resulting cells have not achieved adequate efficiencies. While efficiencies of 11 % have been demonstrated with CuInS2 based cells, the cells produced by this group have shown efficiencies of approximately 1 %. Thus, current research efforts are turning towards the analysis of the individual layers of these cells, as well as the junctions between

  9. Analysis of Electrical Characteristics of Thin Film Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Kasick, Michael P.

    2004-01-01

    Solar energy is the most abundant form of energy in many terrestrial and extraterrestrial environments. Often in extraterrestrial environments sunlight is the only readily available form of energy. Thus the ability to efficiently harness solar energy is one of the ultimate goals in the design of space power systems. The essential component that converts solar energy into electrical energy in a solar energy based power system is the photovoltaic cell. Traditionally, photovoltaic cells are based on a single crystal silicon absorber. While silicon is a well understood technology and yields high efficiency, there are inherent disadvantages to using single crystal materials. The requirements of weight, large planar surfaces, and high manufacturing costs make large silicon cells prohibitively expensive for use in certain applications. Because of silicon s disadvantages, there is considerable ongoing research into alternative photovoltaic technologies. In particular, thin film photovoltaic technologies exhibit a promising future in space power systems. While they are less mature than silicon, the better radiation hardness, reduced weight, ease of manufacturing, low material cost, and the ability to use virtually any exposed surface as a substrate makes thin film technologies very attractive for space applications. The research group lead by Dr. Hepp has spent several years researching copper indium disulfide as an absorber material for use in thin film photovoltaic cells. While the group has succeeded in developing a single source precursor for CuInS2 as well as a unique method of aerosol assisted chemical vapor deposition, the resulting cells have not achieved adequate efficiencies. While efficiencies of 11 % have been demonstrated with CuInS2 based cells, the cells produced by this group have shown efficiencies of approximately 1 %. Thus, current research efforts are turning towards the analysis of the individual layers of these cells, as well as the junctions between

  10. The Photovoltaic Higher Education National Exemplar Facility (PHENEF). Final report, [August 1, 1980--September 30, 1991

    SciTech Connect

    Podbielski, V.; Shaff, D.

    1994-04-01

    In August 1980, the US Department of Energy awarded the proposed grant to Georgetown University. The grant covered the following tasks: Task 1, The Department of Energy would participate in the building of an academic facility that would facilitate the integration of flat plate photovoltaic roof modules with an optimally oriented solar architecture. The completion of the facility to be built on the Georgetown University Campus and known as the Georgetown University Intercultural Center was to be a jointly funded endeavor with the Department of Education funding $9.2M through a grant and a loan, Department of Energy funding a maximum of $4M and Georgetown University funding the residual costs. Task II, Georgetown University would provide the necessary skills, services, materials, equipment and facilities to design, furnish, install and make operational the Georgetown University Intercultural Center Photovoltaic System. The specific objective of this effort would be to build an exemplar flat plate electrical grid connected photovoltaic (PV) system which would demonstrate integration of PV modules into a watertight roofing surface. The system capability, measured at the input to the inverter, would be a 300 kilowatt peak power system as measured at the normal cell operating temperature and an isolation of 100 milliwatts per square centimeter at the collector surface. DOE funding under the grant for the PV system would be limited to a system cost of $20.00 per peak watt up to maximum of six million dollars.

  11. High-performance polymer photovoltaic cells and photodetectors

    NASA Astrophysics Data System (ADS)

    Yu, Gang; Srdanov, Gordana; Wang, Hailiang; Cao, Yong; Heeger, Alan J.

    2001-02-01

    Polymer photovoltaic cells and photodetectors have passed their infancy and become mature technologies. The energy conversion efficiency of polymer photovoltaic cells have been improved to over 4.1% (500 nm, 10 mW/cm2). Such high efficiency polymer photovoltaic cells are promising for many applications including e-papers, e-books and smart- windows. The development of polymer photodetectors is even faster. The performance parameters have been improved to the level meeting all specifications for practical applications. The polymer photodetectors are of high photosensitivity (approximately 0.2 - 0.3 A/Watt in visible and UV), low dark current (0.1 - 1 nA/cm2), large dynamic range (> 8 orders of magnitude), linear intensity dependence, low noise level and fast response time (to nanosecond time domain). These devices show long shelf and operation lives. The advantages of low manufacturing cost, large detection area, and easy hybridization and integration with other electronic or optical components make the polymer photodetectors promising for a variety of applications including chemical/biomedical analysis, full-color digital image sensing and high energy radiation detection.

  12. Two terminal diagnostics for cells in series connected photovoltaic modules

    SciTech Connect

    McMahon, T.J.; Basso, T.S.

    1995-11-01

    The authors have developed a method that allows us to know if a cell`s shunt resistance is affecting the output of a two-terminal, series-connected photovoltaic module, without the need of encapsulation. This two-terminal diagnostic method directly measures the shunt resistance of the individual cells within a series-connected module non-intrusively. Being a phase sensitive, lock-in technique, individual cell shunt resistance values are measured over a wide range, from a fraction of an ohm to thousands of ohms. The authors have applied this method to amorphous Si, Si and CuInSe{sub 2}-based modules, some with as few as eight cells in series, but usually with 28 to 68 cells. ``Two-terminal values`` are more accurate for cells that have lower shunt resistance, i.e., the ``problem`` cells. Cells with visual defects may be a significant problem if they provide a substantial shunt path.

  13. Temperature dependence of photovoltaic cells, modules, and systems

    SciTech Connect

    Emery, K.; Burdick, J.; Caiyem, Y.

    1996-09-01

    Photovoltaic (PV) cells and modules are often rated in terms of a set of standard reporting conditions defined by a temperature, spectral irradiance, and total irradiance. Because PV devices operate over a wide range of temperatures and irradiances, the temperature and irradiance related behavior must be known. This paper surveys the temperature dependence of crystalline and thin-film, state-of-the-art, research-size cells, modules, and systems measured by a variety of methods. The various error sources and measurement methods that contribute to cause differences in the temperature coefficient for a given cell or module measured with various methods are discussed.

  14. Temperature dependence of photovoltaic cells, modules, and systems

    SciTech Connect

    Emery, K.; Burdick, J.; Caiyem, Y.

    1996-05-01

    Photovoltaic (PV) cells and modules are often rated in terms of a set of standard reporting conditions defined by a temperature, spectral irradiance, and total irradiance. Because PV devices operates over a wide range of temperatures and irradiances, the temperature and irradiance related behavior must be known. This paper surveys the temperature dependence of crystalline and thin-film, state-of-the-art, research-size cells, modules, and systems measured by a variety of methods. The various error sources and measurement methods that contribute to cause differences in the temperature coefficient for a given cell or module measured with various methods are discussed.

  15. Solar photovoltaic powered refrigerators/freezers for medical use in remote geographic locations. Final report

    SciTech Connect

    Darkazalli, G.; Hein, G.F.

    1983-10-01

    One of the obstacles preventing widespread immunication against disease is the virtual absence of reliable, low maintenance refrigeration systems for storage of vaccines in remote geographic locations. A system which consists of a solar photovoltaic cell array and an integrated refrigerator/freezer-energy storage unit is discussed herein. The array converts solar radiation into direct current (DC) electricity with no moving parts and no intermediate steps. A detailed description of the refrigeration system, its design and an analysis thereof, performance test procedures, and test results are presented. A system schematic is also provided.

  16. Photovoltaic concentrator initiative: Concentrator cell development

    SciTech Connect

    Wohlgemuth, J.H.; Narayanan, S.

    1993-05-01

    This project involves the development of a large-area, low-cost, high-efficiency concentrator solar cell for use in the Entech 22-sun linear-focus Fresnel lens concentrator system. The buried contact solar cell developed at the University of New South Wales was selected for this project. Both Entech and the University of New South Wales are subcontractors. This annual report presents the program efforts from November 1990 through December 1991, including the design of the cell, development of a baseline cell process, and presentation of the results of preliminary cell processing. Important results include a cell designed for operation in a real concentrator system and substitution of mechanical grooving for the previously utilized laser scribing.

  17. Silicon Nitride Antireflection Coatings for Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Johnson, C.; Wydeven, T.; Donohoe, K.

    1984-01-01

    Chemical-vapor deposition adapted to yield graded index of refraction. Silicon nitride deposited in layers, refractive index of which decreases with distance away from cell/coating interface. Changing index of refraction allows adjustment of spectral transmittance for wavelengths which cell is most effective at converting light to electric current. Average conversion efficiency of solar cells increased from 8.84 percent to 12.63 percent.

  18. Electrical research on solar cells and photovoltaic materials

    NASA Technical Reports Server (NTRS)

    Orehotsky, J.

    1984-01-01

    The flat-plate solar cell array program which increases the service lifetime of the photovoltaic modules used for terrestrial energy applications is discussed. The current-voltage response characteristics of the solar cells encapsulated in the modules degrade with service time and this degradation places a limitation on the useful lifetime of the modules. The most desirable flat-plate array system involves solar cells consisting of highly polarizable materials with similar electrochemical potentials where the cells are encapsulated in polymers in which ionic concentrations and mobilities are negligibly small. Another possible mechanism limiting the service lifetime of the photovoltaic modules is the gradual loss of the electrical insulation characteristics of the polymer pottant due to water absorption or due to polymer degradation from light or heat effects. The mechanical properties of various polymer pottant materials and of electrochemical corrosion mechanisms in solar cell material are as follows: (1) electrical and ionic resistivity; (2) water absorption kinetics and water solubility limits; and (3) corrosion characterization of various metallization systems used in solar cell construction.

  19. 77 FR 25400 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-30

    ... International Trade Administration Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules... in this countervailing duty (CVD) investigation of crystalline silicon photovoltaic cells, whether or not assembled into modules (solar cells) from the People's Republic of China (PRC) with the...

  20. 77 FR 73017 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-07

    ... International Trade Administration Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules... issuing a countervailing duty order on crystalline silicon photovoltaic cells, whether or not assembled into modules (solar cells), from the People's Republic of China (PRC). On November 30, 2012, the ITC...

  1. Low cost and efficient photovoltaic conversion by nanocrystalline solar cells

    SciTech Connect

    Graetzel, M.

    1996-09-01

    Solar cells are expected to provide environmentally friendly solutions to the world`s energy supply problem. Learning from the concepts used by green plants we have developed a molecular photovoltaic device whose overall efficiency for AM 1.5 solar light to electricity has already attained 8-11%. The system is based on the sensitization of nanocrystalline oxide films by transition metal charge transfer sensitizers. In analogy to photosynthesis, the new chemical solar cell achieves the separation of the light absorption and charge carrier transport processes. Extraordinary yields for the conversion of incident photons into electric current are obtained, exceeding 90% for transition metal complexes within the wavelength range of their absorption band. The use of molten salt electrolytes together with coordination complexes of ruthenium as sensitizers and adequate sealing technology has endowed these cells with a remarkable stability making practical applications feasible. Seven industrial cooperations are presently involved in the development to bring these cells to the market. The first cells will be applied to supply electric power for consumer electronic devices. The launching of production of several products of this type is imminent and they should be on the market within the next two years. Quite aside from their intrinsic merits as photovoltaic device, the mesoscopic oxide semiconductor films developed in our laboratory offer attractive possibilities for a number of other applications. Thus, the first example of a nanocrystalline rocking chair battery will be demonstrated and its principle briefly discussed.

  2. Retinal light trapping in textured photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Kravets, V. G.; Grigorenko, A. N.

    2010-10-01

    We suggest a new structure for light trapping in solar cells which is loosely based on retina of human eye. In this design, the incident light is scattered by noble metal nanoparticles acting as amacrine retinal cells and then is guided and concentrated by conelike structures. We show that the proposed textured structure should lead to a significant enhancement of optical path of trapped light resulting in a higher degree of light conversion into electric current. The proposed design should work efficiently in direct sunlight and in cloudy weather.

  3. Photovoltaic device

    DOEpatents

    Reese, Jason A.; Keenihan, James R.; Gaston, Ryan S.; Kauffmann, Keith L.; Langmaid, Joseph A.; Lopez, Leonardo C.; Maak, Kevin D.; Mills, Michael E.; Ramesh, Narayan; Teli, Samar R.

    2015-06-02

    The present invention is premised upon an improved photovoltaic device ("PV device"), more particularly to an improved photovoltaic device with a multilayered photovoltaic cell assembly and a body portion joined at an interface region and including an intermediate layer, at least one interconnecting structural member, relieving feature, unique component geometry, or any combination thereof.

  4. Photovoltaic device

    DOEpatents

    Reese, Jason A; Keenihan, James R; Gaston, Ryan S; Kauffmann, Keith L; Langmaid, Joseph A; Lopez, Leonardo; Maak, Kevin D; Mills, Michael E; Ramesh, Narayan; Teli, Samar R

    2017-03-21

    The present invention is premised upon an improved photovoltaic device ("PV device"), more particularly to an improved photovoltaic device with a multilayered photovoltaic cell assembly and a body portion joined at an interface region and including an intermediate layer, at least one interconnecting structural member, relieving feature, unique component geometry, or any combination thereof.

  5. Photovoltaic device

    DOEpatents

    Reese, Jason A.; Keenihan, James R.; Gaston, Ryan S.; Kauffmann, Keith L.; Langmaid, Joseph A.; Lopez, Leonardo C.; Maak, Kevin D.; Mills, Michael E.; Ramesh, Narayan; Teli, Samar R.

    2015-09-01

    The present invention is premised upon an improved photovoltaic device ("PV device"), more particularly to an improved photovoltaic device (10) with a multilayered photovoltaic cell assembly (100) and a body portion (200) joined at an interface region (410) and including an intermediate layer (500), at least one interconnecting structural member (1500), relieving feature (2500), unique component geometry, or any combination thereof.

  6. Effect of COOH-functionalized SWCNT addition on the electrical and photovoltaic characteristics of Malachite Green dye based photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Chakraborty, S.; Manik, N. B.

    2014-12-01

    We report the effect of COOH-functionalized single walled carbon nanotubes (COOH-SWCNT) on the electrical and photovoltaic characteristics of Malachite Green (MG) dye based photovoltaic cells. Two different types of photovoltaic cells were prepared, one with MG dye and another by incorporating COOH-SWCNT with this dye. Cells were characterized through different electrical and photovoltaic measurements including photocurrent measurements with pulsed radiation. From the dark current—voltage (I-V) characteristic results, we observed a certain transition voltage (Vth) for both the cells beyond which the conduction mechanism of the cells change sharply. For the MG dye, Vth is 3.9 V whereas for COOH-SWCNT mixed with this dye, Vth drops to 2.7 V. The device performance improves due to the incorporation of COOH-SWCNT. The open circuit voltage and short circuit current density change from 4.2 to 97 mV and from 108 to 965 μA/cm2 respectively. Observations from photocurrent measurements show that the rate of growth and decay of the photocurrent are quite faster in the presence of COOH-SWCNT. This observation indicates a faster charge separation processes due to the incorporation of COOH-SWCNT in the MG dye cells. The high aspect ratio of COOH-SWCNT allows efficient conduction pathways for the generated charge carriers.

  7. Silicon wafer-based tandem cells: The ultimate photovoltaic solution?

    NASA Astrophysics Data System (ADS)

    Green, Martin A.

    2014-03-01

    Recent large price reductions with wafer-based cells have increased the difficulty of dislodging silicon solar cell technology from its dominant market position. With market leaders expected to be manufacturing modules above 16% efficiency at 0.36/Watt by 2017, even the cost per unit area (60-70/m2) will be difficult for any thin-film photovoltaic technology to significantly undercut. This may make dislodgement likely only by appreciably higher energy conversion efficiency approaches. A silicon wafer-based cell able to capitalize on on-going cost reductions within the mainstream industry, but with an appreciably higher than present efficiency, might therefore provide the ultimate PV solution. With average selling prices of 156 mm quasi-square monocrystalline Si photovoltaic wafers recently approaching 1 (per wafer), wafers now provide clean, low cost templates for overgrowth of thin, wider bandgap high performance cells, nearly doubling silicon's ultimate efficiency potential. The range of possible Si-based tandem approaches is reviewed together with recent results and ultimate prospects.

  8. Laterally inherently thin amorphous-crystalline silicon heterojunction photovoltaic cell

    SciTech Connect

    Chowdhury, Zahidur R. Kherani, Nazir P.

    2014-12-29

    This article reports on an amorphous-crystalline silicon heterojunction photovoltaic cell concept wherein the heterojunction regions are laterally narrow and distributed amidst a backdrop of well-passivated crystalline silicon surface. The localized amorphous-crystalline silicon heterojunctions consisting of the laterally thin emitter and back-surface field regions are precisely aligned under the metal grid-lines and bus-bars while the remaining crystalline silicon surface is passivated using the recently proposed facile grown native oxide–plasma enhanced chemical vapour deposited silicon nitride passivation scheme. The proposed cell concept mitigates parasitic optical absorption losses by relegating amorphous silicon to beneath the shadowed metallized regions and by using optically transparent passivation layer. A photovoltaic conversion efficiency of 13.6% is obtained for an untextured proof-of-concept cell illuminated under AM 1.5 global spectrum; the specific cell performance parameters are V{sub OC} of 666 mV, J{sub SC} of 29.5 mA-cm{sup −2}, and fill-factor of 69.3%. Reduced parasitic absorption, predominantly in the shorter wavelength range, is confirmed with external quantum efficiency measurement.

  9. Laterally inherently thin amorphous-crystalline silicon heterojunction photovoltaic cell

    NASA Astrophysics Data System (ADS)

    Chowdhury, Zahidur R.; Kherani, Nazir P.

    2014-12-01

    This article reports on an amorphous-crystalline silicon heterojunction photovoltaic cell concept wherein the heterojunction regions are laterally narrow and distributed amidst a backdrop of well-passivated crystalline silicon surface. The localized amorphous-crystalline silicon heterojunctions consisting of the laterally thin emitter and back-surface field regions are precisely aligned under the metal grid-lines and bus-bars while the remaining crystalline silicon surface is passivated using the recently proposed facile grown native oxide-plasma enhanced chemical vapour deposited silicon nitride passivation scheme. The proposed cell concept mitigates parasitic optical absorption losses by relegating amorphous silicon to beneath the shadowed metallized regions and by using optically transparent passivation layer. A photovoltaic conversion efficiency of 13.6% is obtained for an untextured proof-of-concept cell illuminated under AM 1.5 global spectrum; the specific cell performance parameters are VOC of 666 mV, JSC of 29.5 mA-cm-2, and fill-factor of 69.3%. Reduced parasitic absorption, predominantly in the shorter wavelength range, is confirmed with external quantum efficiency measurement.

  10. Organic photovoltaic solar cells with cathode modified by ZnO.

    PubMed

    Kim, Hyeong Pil; Yusoff, Abd Rashid Bin Mohd; Jang, Jin

    2013-07-01

    Solution processed cathode organic photovoltaic cells (OPVs) utilizing thin layer of ZnO with 27% increase in power conversion efficiency (PCE) to control devices have been demonstrated. Devices without the presence of ZnO layer have much lower PCE than the ones with ZnO layer. Cathode modification layer can be used to reduce photogenerated excitions and finally improve the performance of the OPVs. The successful demonstrations of OPVs with an introduction of ZnO cathode layer give promise of further device progresses.

  11. Photovoltaic cell with light trapping for enhanced efficiency

    SciTech Connect

    Brener, Igal; Fofang, Nche Tumasang; Luk, Ting S.

    2015-11-19

    The efficiency of a photovoltaic cell is enhanced by light trapping using Mie-scattering nanostructures. In one embodiment, an array of nanocylinders is formed on the front surface of a silicon film to enhance forward scattering into the film, and an array of nanocylinders is formed on the back surface to enhance backscattering so that more light is absorbed within the silicon film. In an alternate embodiment, a mirror layer is formed on the back surface of the silicon film to reflect light within the film back toward the front-surface nanocylinder array.

  12. A new flame monitor with triple photovoltaic cells

    SciTech Connect

    Xu, L.J.; Yan, Y.

    2006-08-15

    In this paper, we present a new flame monitor that uses three photovoltaic cells covering the ultraviolet (UV), visible, and infrared (IR) spectral bands. A gain-adjustable amplifier is incorporated into the monitor so that it is applicable to the coal-, oil-, or gas-fired flames. Self-checking of the monitor is implemented through cross correlation of the signals from the three cells, and hence, no additional self-checking hardware is required. Both the oscillation frequency and the brightness of the flame are used to monitor flame stability and to detect flame presence as well as sighting-tube blockage. Unlike conventional single-cell flame detectors, the new multicell devices can still be in operation before being repaired, after a cell-failure alarm has gone off. Experiments were carried out on an industrial-scale combustion test facility in order to demonstrate the operability and efficacy of the new flame monitor.

  13. Advanced tendencies in development of photovoltaic cells for power engineering

    NASA Astrophysics Data System (ADS)

    Strebkov, D. S.

    2015-01-01

    Development of solar power engineering must be based on original innovative Russian and world technologies. It is necessary to develop promising Russian technologies of manufacturing of photovoltaic cells and semiconductor materials: chlorine-free technology for obtaining solar silicon; matrix solar cell technology with an efficiency of 25-30% upon the conversion of concentrated solar, thermal, and laser radiation; encapsulation technology for high-voltage silicon solar modules with a voltage up to 1000 V and a service life up to 50 years; new methods of concentration of solar radiation with the balancing illumination of photovoltaic cells at 50-100-fold concentration; and solar power systems with round-the-clock production of electrical energy that do not require energy storage devices and reserve sources of energy. The advanced tendency in silicon power engineering is the use of high-temperature reactions in heterogeneous modular silicate solutions for long-term (over one year) production of heat and electricity in the autonomous mode.

  14. Semi-transparent polymer solar cells with excellent sub-bandgap transmission for third generation photovoltaics.

    PubMed

    Beiley, Zach M; Christoforo, M Greyson; Gratia, Paul; Bowring, Andrea R; Eberspacher, Petra; Margulis, George Y; Cabanetos, Clément; Beaujuge, Pierre M; Salleo, Alberto; McGehee, Michael D

    2013-12-23

    Semi-transparent organic photovoltaics are of interest for a variety of photovoltaic applications, including solar windows and hybrid tandem photovoltaics. The figure shows a photograph of our semi-transparent solar cell, which has a power conversion efficiency of 5.0%, with an above bandgap transmission of 34% and a sub-bandgap transmission of 81%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Magnetic field enhancement of organic photovoltaic cells performance.

    PubMed

    Oviedo-Casado, S; Urbina, A; Prior, J

    2017-06-27

    Charge separation is a critical process for achieving high efficiencies in organic photovoltaic cells. The initial tightly bound excitonic electron-hole pair has to dissociate fast enough in order to avoid photocurrent generation and thus power conversion efficiency loss via geminate recombination. Such process takes place assisted by transitional states that lie between the initial exciton and the free charge state. Due to spin conservation rules these intermediate charge transfer states typically have singlet character. Here we propose a donor-acceptor model for a generic organic photovoltaic cell in which the process of charge separation is modulated by a magnetic field which tunes the energy levels. The impact of a magnetic field is to intensify the generation of charge transfer states with triplet character via inter-system crossing. As the ground state of the system has singlet character, triplet states are recombination-protected, thus leading to a higher probability of successful charge separation. Using the open quantum systems formalism we demonstrate that the population of triplet charge transfer states grows in the presence of a magnetic field, and discuss the impact on carrier population and hence photocurrent, highlighting its potential as a tool for research on charge transfer kinetics in this complex systems.

  16. Method of improving photoelectric efficiency for laser power beaming based on photovoltaic cell layout optimization

    NASA Astrophysics Data System (ADS)

    Li, Beibei; Li, Xiaojiang

    2017-02-01

    In accordance with the high impact of the uneven distribution of laser beam power on the photovoltaic efficiency of photovoltaic cell (PV) array, a method based on PV layout optimization is proposed to improve the photovoltaic efficiency. First of all, a mathematical model of series-parallel PV array is built, and by analyzing the influencing factors on photovoltaic efficiency, the idea and scheme to improve the photovoltaic efficiency based on PV layout optimization is provided; then, the MATLAB/Simulink simulation tool is used to simulate the effects of improving photoelectric efficiency. The simulation results show that compared to the traditional PV array, the optimized PV array can obtain higher photovoltaic efficiency, and compared to the situation with uneven temperature distribution, the array efficiency has higher efficiency under even temperature distribution.

  17. Quantum Dot Solar Cells. The Next Big Thing in Photovoltaics.

    PubMed

    Kamat, Prashant V

    2013-03-21

    The recent surge in the utilization of semiconductor nanostructures for solar energy conversion has led to the development of high-efficiency solar cells. Some of these recent advances are in the areas of synthesis of new semiconductor materials and the ability to tune the electronic properties through size, shape, and composition and to assemble quantum dots as hybrid assemblies. In addition, processes such as hot electron injection, multiple exciton generation (MEG), plasmonic effects, and energy-transfer-coupled electron transfer are gaining momentum to overcome the efficiency limitations of energy capture and conversion. The recent advances as well as future prospects of quantum dot solar cells discussed in this perspective provide the basis for consideration as "The Next Big Thing" in photovoltaics.

  18. Efficient organic photovoltaic cells with vertically ordered bulk heterojunctions.

    PubMed

    Yu, Bo; Wang, Haibo; Yan, Donghang

    2013-12-06

    Nanoscale morphology has been proved to be the key parameter deciding the exciton dissociation and charge transportation in bulk heterojunction (BHJ) solar cells. In this paper, we report a kind of small molecular organic photovoltaic cell (OPV) with a vertically ordered BHJ prepared by the weak epitaxial growth method. By this method, zinc phthalocyanine (ZnPc) can easily be formed into a highly ordered and continuous thin film and C60 is inclined to become dispersed crystalline grains in ZnPc film. Furthermore, we can control both the size and distribution density of C60 crystalline grains in ZnPc thin film without destroying the order of the ZnPc thin film. The OPVs with the vertically ordered BHJ show a high fill factor and a power conversion efficiency over 3% has been achieved.

  19. Photovoltaic measurements in single-nanowire silicon solar cells.

    PubMed

    Kelzenberg, Michael D; Turner-Evans, Daniel B; Kayes, Brendan M; Filler, Michael A; Putnam, Morgan C; Lewis, Nathan S; Atwater, Harry A

    2008-02-01

    Single-nanowire solar cells were created by forming rectifying junctions in electrically contacted vapor-liquid-solid-grown Si nanowires. The nanowires had diameters in the range of 200 nm to 1.5 microm. Dark and light current-voltage measurements were made under simulated Air Mass 1.5 global illumination. Photovoltaic spectral response measurements were also performed. Scanning photocurrent microscopy indicated that the Si nanowire devices had minority carrier diffusion lengths of approximately 2 microm. Assuming bulk-dominated recombination, this value corresponds to a minimum carrier lifetime of approximately 15 ns, or assuming surface-dominated recombination, to a maximum surface recombination velocity of approximately 1350 cm s(-1). The methods described herein comprise a valuable platform for measuring the properties of semiconductor nanowires, and are expected to be instrumental when designing an efficient macroscopic solar cell based on arrays of such nanostructures.

  20. Electrical research on solar cells and photovoltaic materials

    NASA Technical Reports Server (NTRS)

    Orehotsky, J.

    1985-01-01

    A systematic study of the properties of various polymer pottant materials and of the electrochemical corrosion mechanisms in solar cell materials is required for advancing the technology of terrestrial photovoltaic modules. The items of specific concern in this sponsored research activity involve: (1) kinetics of plasticizer loss in PVB, (2) kinetics of water absorption and desorption in PVB, (3) kinetics of water absorption and desorption in EVA, (4) the electrical properties at PVB as a function of temperature and humidity, (5) the electrical properties of EVA as a function of temperature and humidity, (6) solar cell corrosion characteristics, (7) water absorption effects in PVB and EVA, and (8) ion implantation and radiation effects in PVB and EVA.

  1. The efficiency of photovoltaic cells exposed to pulsed laser light

    NASA Technical Reports Server (NTRS)

    Lowe, R. A.; Landis, G. A.; Jenkins, P.

    1993-01-01

    Future space missions may use laser power beaming systems with a free electron laser (FEL) to transmit light to a photovoltaic array receiver. To investigate the efficiency of solar cells with pulsed laser light, several types of GaAs, Si, CuInSe2, and GaSb cells were tested with the simulated pulse format of the induction and radio frequency (RF) FEL. The induction pulse format was simulated with an 800-watt average power copper vapor laser and the RF format with a frequency-doubled mode-locked Nd:YAG laser. Averaged current vs bias voltage measurements for each cell were taken at various optical power levels and the efficiency measured at the maximum power point. Experimental results show that the conversion efficiency for the cells tested is highly dependent on cell minority carrier lifetime, the width and frequency of the pulses, load impedance, and the average incident power. Three main effects were found to decrease the efficiency of solar cells exposed to simulated FEL illumination: cell series resistance, LC 'ringing', and output inductance. Improvements in efficiency were achieved by modifying the frequency response of the cell to match the spectral energy content of the laser pulse with external passive components.

  2. [Prediction of Encapsulation Temperatures of Copolymer Films in Photovoltaic Cells Using Hyperspectral Imaging Techniques and Chemometrics].

    PubMed

    Lin, Ping; Chen, Yong-ming; Yao, Zhi-lei

    2015-11-01

    introduced to eliminate the impact of nonlinear hyperspectral data to some extent through mapping the original nonlinear hyperspectral data to the high dimensional linear feature space, so the relationship between the nonlinear hyperspectral data and the encapsulation temperatures of EVA films was fully disclosed finally. Compared with the prediction results of three proposed models, the prediction performance of LMNN was superior to the other two, whose final recognition accuracy achieved 100%. The results indicated that the methods of combination of LMNN model with the hyperspectral imaging techniques was the best one for accurately and rapidly determining the encapsulation temperatures of EVA films of photovoltaic cells. In addition, this paper had created the ideal conditions for automatically monitoring and effectively controlling the encapsulation temperatures of EVA films in the photovoltaic cells production process.

  3. A surface plasmon enabled liquid-junction photovoltaic cell

    SciTech Connect

    Lee, Woo-ram; Mubeen, Syed; Stucky, Galen D.; Moskovits, Martin

    2014-10-16

    Plasmonic nanosystems have recently been shown to be capable of functioning as photovoltaics and of carrying out redox photochemistry, purportedly using the energetic electrons and holes created following plasmonic decay as charge carriers. Although such devices currently have low efficiency, they already manifest a number of favorable characteristics, such as their tunability over the entire solar spectrum and a remarkable resistance to photocorrosion. Here, we report a plasmonic photovoltaic using a 25 μm thick electrolytic liquid junction which supports the iodide/triiodide (I-/I3-) redox couple. The device produces photocurrent densities in excess of 40 μA cm-2, an open circuit voltage (Voc) of ~0.24 V and a fill factor of ~0.5 using AM 1.5 G solar radiation at 100 mW cm-2. The photocurrent and the power conversion efficiency are primarily limited by the low light absorption in the 2-D gold nanoparticle arrays. The use of a liquid junction greatly reduces dielectric breakdown in the oxide layers utilized, which must be very thin for optimal performance, leading to a great improvement in the long-term stability of the cell's performance.

  4. Simplified calculation of solar cell temperatures in terrestrial photovoltaic arrays

    NASA Astrophysics Data System (ADS)

    Ingersoll, J. G.

    1984-12-01

    A simplified algorithm to predict the average steady-state temperature of the solar cells in a photovoltaic array has been developed. The methodology can be applied to arrays on the roof (or walls) of buildings as well as on the ground. It is intended primarily for residential buildings, although it can be used for any type of building, and considers all four-array mounting systems (rack, stand-off, direct, and integral). Input parameters in this development include weather (insolation, ambient temperature, wind speed, humidity, and sky cloud cover), as well as building construction and operation characteristics. The photovoltaic array's geometrical, optical, and thermal properties are used in the analysis as well. Natural or forced convection under the solar panels and/or in the building attic below can also be accounted for by this model. The model has been partially verified against limited measured data and found to be in very good agreement for wind speeds of 1 m/s or more.

  5. InGaN High-Temperature Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Starikov, David

    2015-01-01

    This Phase II project developed Indium-Gallium-Nitride (InGaN) photovoltaic cells for high-temperature and high-radiation environments. The project included theoretical and experimental refinement of device structures produced in Phase I as well as modeling and optimization of solar cell device processing. The devices have been tested under concentrated air mass zero (AM0) sunlight, at temperatures from 100 degC to 250 degC, and after exposure to ionizing radiation. The results are expected to further verify that InGaN can be used for high-temperature and high-radiation solar cells. The large commercial solar cell market could benefit from the hybridization of InGaN materials to existing solar cell technology, which would significantly increase cell efficiency without relying on highly toxic compounds. In addition, further development of this technology to even lower bandgap materials for space applications would extend lifetimes of satellite solar cell arrays due to increased radiation hardness. This could be of importance to the Departmentof Defense (DoD) and commercial satellite manufacturers.

  6. Safety-related requirements for photovoltaic modules and arrays. Final report

    SciTech Connect

    Levins, A.

    1984-03-01

    Underwriters Laboratories has conducted a study to identify and develop safety requirements for photovoltaic module and panel designs and configurations for residential, intermediate, and large scale applications. Concepts for safety systems, where each system is a collection of subsystems which together address the total anticipated hazard situation, are described. Descriptions of hardware, and system usefulness and viability are included. This discussion of safety systems recognizes that there is little history on which to base the expected safety related performance of a photovoltaic system. A comparison of these systems, as against the provisions of the 1984 National Electrical Code covering photovoltaic systems is made. A discussion of the UL investigation of the photovoltaic module evaluated to the provisions of the Proposed UL Standard for Flat-Plate Photovoltaic Modules and Panels is included. Grounding systems, their basis and nature, and the advantages and disadvantages of each are described. The meaning of frame grounding, circuit grounding, and the type of circuit ground are covered. The development of the Standard for Flat-Plate Photovoltaic Modules and Panels has continued, and with both industry comment and a product submittal and listing, the Standard has been refined to a viable document allowing an objective safety review of photovoltaic modules and panels. How this document, and other UL documents would cover investigations of certain other photovoltaic system components is described.

  7. Solar cells design for low and medium concentrating photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Baig, Hasan; Heasman, Keith C.; Sarmah, Nabin; Mallick, Tapas

    2012-10-01

    The solar cell is the key element of any CPV system, and its design plays an important role in enhancing the performance of the entire system. Special types of cells are required in the CPV systems capable of operating at high concentrations and elevated temperatures. These Concentrator solar cells differ significantly from the usual solar cells in the method of manufacture, the overall cell design and their performance. Systematic design and manufacture of the cell ensures better performance in a given CPV system. A number of factors come into play while designing the solar cell for a specific system these include concentration, cell material properties, expected operating temperature, shape, bus bar configuration and finger spacing. Most of these variables are decided on based on some rules of thumb and PC1D calculations. However, there is scope for design improvement and cell optimization by performing a detailed analysis based on the illumination profile incident on the cell. Recent studies demonstrated the use of Finite element method to analyze the electrical behavior of PV cell under the influence of arbitrarily chosen illumination flux profiles. This study outlines a methodology and analysis procedure while performing a case study of a CPV system under development having a non-uniform illumination profile towards the exit of the concentrator. The LCPV system chosen is the Photovoltaic Facades of Reduced Costs Incorporating Devices with Optically Concentrating Elements (PRIDE) concentrator made of dielectric material. A coupled optical, thermal and electrical analysis is performed on the system to demonstrate the method useful in designing solar cells for low and medium concentrations.

  8. Photovoltaic field test performance assessment. Technology status report No. 4. Final report

    SciTech Connect

    Mayorga, H.; Hostetler, R.

    1986-03-01

    Descriptions of 1984 performance are provided for five fixed-tilt flat plate, one tracking flat plate, and two concentrator photovoltaic systems. They range in size from 18 kW to 1000 kW. All of the systems have extensive instrumentation; performance readings are generally available every 10 minutes. Installations vary in energy efficiency. The older, fixed-tilt, flat plate sites have the lowest efficiency (5%). Next are the newer flat plate sites of both fixed-tilt and tracking types (6 to 7%). The Fresnel lens concentrator sites have the highest efficiency (6 to 9%). Installations vary widely in availability. Power conditioning unit failure is the largest contributor to decreased availability. In general, nameplate ratings are optimistic. Observed power output equals these ratings only under rare combinations of high insolation and low ambient temperature. Degradation in energy efficiency may be occurring at Oklahoma City. The tracking flat plate site demonstrates high energy capture and capacity factor. The Fresnel lens concentrators are especially sensitive to tracking error and cloudiness. At flat plate sites that have monocrystalline silicon cells, energy efficiency is fairly constant with insolation. At flat plate sites using polycrystalline cells, energy efficiency increases with insolation. At the Fresnel lens concentrator sites (both using monocrystalline cells), energy efficiency increases with insolation. Problems, mostly of the hardware type, with the on-site data acquisition system continue to hinder data collection.

  9. Concrete Embedded Dye-Synthesized Photovoltaic Solar Cell

    PubMed Central

    Hosseini, T.; Flores-Vivian, I.; Sobolev, K.; Kouklin, N.

    2013-01-01

    This work presents the concept of a monolithic concrete-integrated dye-synthesized photovoltaic solar cell for optical-to-electrical energy conversion and on-site power generation. The transport measurements carried out in the dark revealed the presence of VOC of ~190 mV and ISC of ~9 μA, induced by the electrochemical conversion of concrete-supplied ionic impurities at the electrodes. The current-voltage measurements performed under illumination at incident optical powers of ~46 mW confirmed the generation of electrical power of ~0.64 μW with almost half generated via battery effect. This work presents a first step towards realizing the additional pathways to low-cost electrical power production in urban environments based on a combined use of organic dyes, nanotitania and concrete technology. PMID:24067664

  10. Dye Sensitized Solar Cells for Economically Viable Photovoltaic Systems.

    PubMed

    Jung, Hyun Suk; Lee, Jung-Kun

    2013-05-16

    TiO2 nanoparticle-based dye sensitized solar cells (DSSCs) have attracted a significant level of scientific and technological interest for their potential as economically viable photovoltaic devices. While DSSCs have multiple benefits such as material abundance, a short energy payback period, constant power output, and compatibility with flexible applications, there are still several challenges that hold back large scale commercialization. Critical factors determining the future of DSSCs involve energy conversion efficiency, long-term stability, and production cost. Continuous advancement of their long-term stability suggests that state-of-the-art DSSCs will operate for over 20 years without a significant decrease in performance. Nevertheless, key questions remain in regards to energy conversion efficiency improvements and material cost reduction. In this Perspective, the present state of the field and the ongoing efforts to address the requirements of DSSCs are summarized with views on the future of DSSCs.

  11. Polymer heterostructures with embedded carbon nanotubes for efficient photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Previti, F.; Patanè, S.; Allegrini, M.

    2009-09-01

    Polymer photovoltaic cells (PVC) are intensely investigated because of their potential advantages over Si-based PVCs. Their present drawbacks are low conversion efficiency, limited exciton diffusion length, poor hole carriers transport and short lifetime. The highest conversion efficiency achieved so far in spin-coated polymer blends is close to 5%. Recently, efficiency growing has been demonstrated in multilayer architectures involving a donor/acceptor bulk heterojunction. Alternatively, a nanomaterial has been added to the polymer active layer to facilitate excitons dissociation and carriers transport through the polymer matrix. In this work we investigate both these approaches, first embedding single wall Carbon Nanotubes (SWCNT) in the polymeric matrix to improve the electrical transport and second studying the optical absorption of different polymer thin films to optimize the spectral response of the donor/acceptor heterojunction.

  12. Concrete embedded dye-synthesized photovoltaic solar cell.

    PubMed

    Hosseini, T; Flores-Vivian, I; Sobolev, K; Kouklin, N

    2013-09-25

    This work presents the concept of a monolithic concrete-integrated dye-synthesized photovoltaic solar cell for optical-to-electrical energy conversion and on-site power generation. The transport measurements carried out in the dark revealed the presence of VOC of ~190 mV and ISC of ~9 μA, induced by the electrochemical conversion of concrete-supplied ionic impurities at the electrodes. The current-voltage measurements performed under illumination at incident optical powers of ~46 mW confirmed the generation of electrical power of ~0.64 μW with almost half generated via battery effect. This work presents a first step towards realizing the additional pathways to low-cost electrical power production in urban environments based on a combined use of organic dyes, nanotitania and concrete technology.

  13. Organic photovoltaic cells: from performance improvement to manufacturing processes.

    PubMed

    Youn, Hongseok; Park, Hui Joon; Guo, L Jay

    2015-05-20

    Organic photovoltaics (OPVs) have been pursued as a next generation power source due to their light weight, thin, flexible, and simple fabrication advantages. Improvements in OPV efficiency have attracted great attention in the past decade. Because the functional layers in OPVs can be dissolved in common solvents, they can be manufactured by eco-friendly and scalable printing or coating technologies. In this review article, the focus is on recent efforts to control nanomorphologies of photoactive layer and discussion of various solution-processed charge transport and extraction materials, to maximize the performance of OPV cells. Next, recent works on printing and coating technologies for OPVs to realize solution processing are reviewed. The review concludes with a discussion of recent advances in the development of non-traditional lamination and transfer method towards highly efficient and fully solution-processed OPV.

  14. Graphene - a promising material for organic photovoltaic cells.

    PubMed

    Wan, Xiangjian; Long, Guankui; Huang, Lu; Chen, Yongsheng

    2011-12-01

    As a promising two-dimensional nanomaterial with outstanding electronic, optical, thermal, and mechanical properties, graphene has been proposed for many applications. In this Progress Report we summarize and discuss comprehensively the advances made so far for applications of graphene in organic photovoltaic (OPV) cells, including that for transparent electrodes, active layers and interfaces layer in OPV. It is concluded that graphene may very likely play a major role in new developments/improvements in OPVs. The future studies for this area are proposed to focus on the following: i) improving the conductivity without comprising the transparency as a transparent electrode material; ii) controlling the sheet sizes, band structure and surface morphology for use as a electron acceptor material, and iii) controlling and improving the functionalization and compatibility with other materials as interface layer material.

  15. A four-cell photovoltaic system based on InP and GaAs

    NASA Astrophysics Data System (ADS)

    Beaumont, B.; Nataf, G.; Raymond, F.; Verie, C.

    A four-bandgap photovoltaic system is proposed. It combines two monolithic, stacked two-bandgap solar cells coupled through a dichroic mirror. Detailed modelling studies, together with a discussion on the choice of semiconducting materials for the photovoltaic cells, are described. The projected operating efficiency is shown to be above 35 percent, reaching a value as high as 42 percent in the case of the four-cell converter. Experiments are under progress.

  16. A heterojunction photovoltaic cell based on a mixture of silane copolymer with C70 fullerene derivative

    NASA Astrophysics Data System (ADS)

    Kostromin, S. V.; Malov, V. V.; Tameev, A. R.; Bronnikov, S. V.; Sacarescu, L.

    2016-01-01

    Heterojunction photovoltaic cells with a photoactive layer composed of a mixture of a silane copolymer with a fullerene derivative PC70BM have been fabricated, and their working characteristics have been measured. Data obtained by cyclic voltammetry were used to construct the energy level diagram for the cell components. Analysis of the diagram and photoelectric characteristics of the photovoltaic cell made it possible to find ways to improve its efficiency.

  17. The Effects of Cells Temperature Increment and Variations of Irradiation for Monocrystalline Photovoltaic

    NASA Astrophysics Data System (ADS)

    Fuad Rahman Soeharto, Faishal; Hermawan

    2017-04-01

    Photovoltaic cell technology has been developed to meet the target of 17% Renewable Energy in 2025 accordance with Indonesia Government Regulation No. 5 2006. Photovoltaic cells are made of semiconductor materials, namely silicon or germanium (p-n junction). These cells need the light that comes from solar irradiation which brings energy photons to convert light energy into electrical energy. It is different from the solar heater that requires heat energy or thermal of sunlight that is normally used for drying or heating water. Photovoltaic cells requires energy photons to perform the energy conversion process, the photon energy can be derived from sunlight. Energy photon is taken from the sun light along with the advent of heat due to black-body radiation, which can lead to temperature increments of photovoltaic cells. Increment of 1°C can decreased photovoltaic cell voltage of up to 2.3 mV per cell. In this research, it will be discuss the analysis of the effect of rising temperatures and variations of irradiation on the type monocrystalline photovoltaic. Those variation are analyzed, simulated and experiment by using a module of experiment. The test results show that increment temperature from 25° C to 80° C at cell of photovoltaic decrease the output voltage of the photovoltaic cell at 4.21 V, and it also affect the power output of the cell which decreases up to 0.7523 Watt. In addition, the bigger the value of irradiation received by cell at amount of 1000 W / m2, produce more output power cells at the same temperature.

  18. Transparent, near-infrared organic photovoltaic solar cells for window and energy-scavenging applications

    SciTech Connect

    Lunt, Richard R; Bulovic, Vladimir

    2011-03-14

    We fabricate near-infrared absorbing organic photovoltaics that are highly transparent to visible light. By optimizing near-infrared optical-interference, we demonstrate power efficiencies of 1.3±0.1% with simultaneous average visible transmission of >65% . Subsequent incorporation of near-infrared distributed-Bragg-reflector mirrors leads to an increase in the efficiency to 1.7±0.1% , approaching the 2.4±0.2% efficiency of the opaque cell, while maintaining high visible-transparency of >55% . Finally, we demonstrate that a series-integrated array of these transparent cells is capable of powering electronic devices under near-ambient lighting. This architecture suggests strategies for high-efficiency power-generating windows and highlights an application uniquely benefiting from excitonic electronics.

  19. Fullerene derivatives as electron donor for organic photovoltaic cells

    SciTech Connect

    Zhuang, Taojun; Wang, Xiao-Feng E-mail: ziruo@yz.yamagata-u.ac.jp; Sano, Takeshi; Kido, Junji; Hong, Ziruo E-mail: ziruo@yz.yamagata-u.ac.jp; Yang, Yang

    2013-11-11

    We demonstrated the performance of unconventional, all-fullerene-based, planar heterojunction (PHJ) organic photovoltaic (OPV) cells using fullerene derivatives indene-C{sub 60} bisadduct (ICBA) and phenyl C{sub 61}-butyric acid methyl ester as the electron donors with fullerene C{sub 70} as the electron acceptor. Two different charge generation processes, including charge generation in the fullerene bulk and exciton dissociation at the donor-acceptor interface, have been found to exist in such all-fullerene-based PHJ cells and the contribution to the total photocurrent from each process is strongly dependent on the thickness of fullerene donor. The optimized 5 nm ICBA/40 nm C{sub 70} PHJ cell gives clear external quantum efficiency responses for the long-wavelength photons corresponding to the dissociation of strongly bound Frenkel excitons, which is hardly observed in fullerene-based single layer reference devices. This approach using fullerene as a donor material provides further possibilities for developing high performance OPV cells.

  20. Metallic nanoparticle deposition techniques for enhanced organic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Cacha, Brian Joseph Gonda

    Energy generation via organic photovoltaic (OPV) cells provide many advantages over alternative processes including flexibility and price. However, more efficient OPVs are required in order to be competitive for applications. One way to enhance efficiency is through manipulation of exciton mechanisms within the OPV, for example by inserting a thin film of bathocuproine (BCP) and gold nanoparticles between the C60/Al and ZnPc/ITO interfaces, respectively. We find that BCP increases efficiencies by 330% due to gains of open circuit voltage (Voc) by 160% and short circuit current (Jsc) by 130%. However, these gains are complicated by the anomalous photovoltaic effect and an internal chemical potential. Exploration in the tuning of metallic nanoparticle deposition on ITO was done through four techniques. Drop casting Ag nanoparticle solution showed arduous control on deposited morphology. Spin-coating deposited very low densities of nanoparticles. Drop casting and spin-coating methods showed arduous control on Ag nanoparticle morphology due to clustering and low deposition density, respectively. Sputtered gold on glass was initially created to aid the adherence of Ag nanoparticles but instead showed a quick way to deposit aggregated gold nanoparticles. Electrodeposition of gold nanoparticles (AuNP) proved a quick method to tune nanoparticle morphology on ITO substrates. Control of deposition parameters affected AuNP size and distribution. AFM images of electrodeposited AuNPs showed sizes ranging from 39 to 58 nm. UV-Vis spectroscopy showed the presence of localized plasmon resonance through absorption peaks ranging from 503 to 614 nm. A linear correlation between electrodeposited AuNP size and peak absorbance was seen with a slope of 3.26 wavelength(nm)/diameter(nm).

  1. Photovoltaic nanocrystal scintillators hybridized on Si solar cells for enhanced conversion efficiency in UV.

    PubMed

    Mutlugun, Evren; Soganci, Ibrahim Murat; Demir, Hilmi Volkan

    2008-03-17

    We propose and demonstrate semiconductor nanocrystal based photovoltaic scintillators integrated on solar cells to enhance photovoltaic device parameters including spectral responsivity, open circuit voltage, short circuit current, fill factor, and solar conversion efficiency in the ultraviolet. Hybridizing (CdSe)ZnS core-shell quantum dots of 2.4 nm in diameter on multi-crystalline Si solar cells for the first time, we show that the solar conversion efficiency is enhanced 2 folds under white light illumination similar to the solar spectrum. Such nanocrystal scintillators provide the ability to extend the photovoltaic activity towards UV.

  2. Sun Valley Photovoltaic Power Project, Phase 1. Final report, June 1, 1978-February 28, 1979

    SciTech Connect

    Goodman, Jr, F R

    1980-03-01

    An application experiment was devised for fabrication, installation, operation, and evaluation of a concentrating photovoltaic system for direct conversion of sunlight to electricity. If the experiment is performed, the photovoltaic system will be connected to an electric motor load and to an electric utility system. Provisions will be made to allow the motor load to be supplied with power from either the photovoltaic system or the utility system. When the demand of the motor load is low, the photovoltaic system will deliver excess power to the utility system for use elsewhere. Thus, the experimental installation has been designed with sufficient flexibility to enable several modes of operation to be evaluated. This type of application is a typical example of on-site power generation at an individual load center involving two-way energy exchange with the adjacent utility system. Because a growing market for photovoltaic systems in this type of application is expected in the 1980's, the experiment will provide needed information in a timely manner. The experiment was devised jointly by the Los Angeles Department of Water and Power (LADWP) and its subcontractor, Spectrolab, Inc. LADWP will furnish a site and operate the equipment after installation. The subcontractor will manufacture and furnish a concentrating photovoltaic array with a power rating of approximately 200 kilowatts at one kilowatt per square meter of insolation. Other required equipment will be purchased to specification from appropriate suppliers. The photovoltaic system represents a state-of-the-art design at the time this report was prepared. However, minor design improvements may be made prior to and during system installation. All phases of fabrication, installation and operation will be documented through formal reports. The results of the experiment will contribute to the goals of the National Photovoltaic Conversion Program.

  3. Integrating Copper Nanowire Electrodes for Low Temperature Perovskite Photovoltaic Cells

    NASA Astrophysics Data System (ADS)

    Mankowski, Trent

    Recent advances in third generation photovoltaics, particularly the rapid increase in perovskite power conversion efficiencies, may provide a cheap alternative to silicon solar cells in the near future. A key component to these devices is the transparent front electrode, and in the case of Dye Sensitized Solar Cells, it is the most expensive part. A lightweight, cost-effective, robust, and easy-to-fabricate new generation TCE is required to enable competition with silicon. Indium Tin Oxide, commonly used in touchscreen devices, Organic Light Emitting Diodes (OLEDs), and thin film photovoltaics, is widely used and commonly referred to as the industry standard. As the global supply of indium decreases and the demand for this TCE increases, a similar alternative TCE is required to accompany the next generation solar cells that promise energy with lighter and significantly cheaper modules. This alternative TCE needs to provide similar sheet resistance and optical transmittance to ITO, while also being mechanically and chemically robust. The work in this thesis begins with an exploration of several synthesized ITO replacement materials, such as copper nanowires, conductive polymer PEDOT:PSS, zinc oxide thin films, reduced graphene oxide and combinations of the above. A guiding philosophy to this work was prioritizing cheap, easy deposition methods and overall scalability. Shortcomings of these TCEs were investigated and different materials were hybridized to take advantage of each layers strengths for development of an ideal ITO replacement. For CuNW-based composite electrodes, 85% optical transmittance and 25 O/sq were observed and characterized to understand the underlying mechanisms for optimization. The second half of this work is an examination of many different perovskite synthesis methods first to achieve highest performance, and then to integrate compatible methods with our CuNW TCEs. Several literature methods investigated were irreproducible, and those that

  4. SolarTile: A rooftop integrated photovoltaic system. Phase 1, final report

    SciTech Connect

    1998-03-26

    AstroPower, Royal Group Technologies, and Solar Design Associates are jointly developing an integrated photovoltaic roofing system for residential and light commercial building applications. This family of products will rely heavily on the technological development of a roofing tile made from recycled plastic and innovative module fabrication and encapsulation processes in conjunction with an advanced Silicon-Film{trademark} solar cell product. This solar power generating roofing product is presently being referred to as the SolarTile. A conceptual drawing of the solar roofing tile is shown. The SolarTile will be integrated with non-solar tiles in a single roof installation permitting ease of assembly and the ability to use conventional roofing techniques at ridges, valleys, and eaves. The Phase 1 effort included tasks aimed at the development of the proposed product concept; product manufacturing or fabrication, and installation cost estimates; business planning; and a market assessment of the proposed product, including target selling prices, target market sectors, size estimates for each market sector, and planned distribution mechanisms for market penetration. Technical goals as stated in the Phase 1 proposal and relevant progress are reported.

  5. Tandem photovoltaic cells with a composite intermediate layer

    SciTech Connect

    Travkin, V. V. Pakhomov, G. L.; Luk’anov, A. Yu.; Stuzhin, P. A.

    2015-11-15

    We have fabricated and tested tandem photovoltaic cells containing series-connected subcells of the “oxide–organic semiconductor–metal” type. The organic semiconductors were two phthalocyanine dyes (SubPc and PcVO); Al or Ag:Mg were used as capping metallic electrodes. A semitransparent composite metal–oxide layer formed by molybdenum oxide MoO{sub x} deposited over an ultrathin Al layer is used to join the subcells. Additionally, a MoO{sub x} layer deposited onto glass/ITO substrates serves as an anode buffer in the front subcell, and LiF deposited onto the dye layers serves as a cathode buffer in the front or rear subcells. Upon optimization of the thickness and composition of the intermediate layer, the open circuit voltage U{sub oc} amounts to 1.6 V reflecting total summation of the contributions from the each of the subcells at a wide spectral coating from 300–1000 nm. The fill factor in the tandem cell is not worse than in individually made single cells with the same scheme or in disconnected subcells.

  6. Magnetic Studies of Photovoltaic Processes in Organic Solar Cells

    SciTech Connect

    Zang, Huidong; Ivanov, Ilia N; Hu, Bin

    2010-01-01

    In this paper, we use magnetic field effects of photocurrent (MFEPC ) to study the photovoltaic processes in pristine conjugated polymer, bulk heterojunction, and double-layer solar cells, respectively, based on poly(3-alkylthiophene) (P3HT). The MFEPC reveals that the photocurrent generation undergoes the dissociation in polaron pair states and the charge reaction in excitonic states in pristine conjugated polymers. As for the bulk-heterojunction solar cells consisting of electron donor P3HT and electron acceptor [6,6]-phenyl C61-butyric acid methyl ester (PCBM), the MFEPC indicates that the dissociated electrons and holes inevitably form the intermolecular charge-transfer (CT) complexes at donor and acceptor interfaces. Essentially, the photocurrent generation relies on the further dissociation of intermolecular CT complexes. Moreover, we use double-layer solar cell to further study the intermolecular CT complexes with well-controlled donor acceptor interfaces based on double-layer P3HT/TiOx design. We find that the increase in free energies can significantly reduce the density of CT complexes upon thermal annealing.

  7. Hybrid solar thermal-photovoltaic systems demonstration, Phase I and II. Final technical progress report, July 5, 1979-December 1982

    SciTech Connect

    Loferski, J.J.

    1983-12-01

    The purpose of the project is to investigate a system based on combined photovoltaic/thermal (PV/T) panels to supply the energy needs of a small single family residence. The system finally selected and constructed uses PV/T panels which utilize air as the heat transfer medium. Optimization of thermal performance was accomplished by attaching metal fins to the back surface of each cell which significantly increased the heat transfer coefficient from the solar cells to the air stream. The other major components of the selected system are an air-to-air heat pump, a rock bin thermal energy storage bin, a synchronous dc-to-ac converter, a microprocessor to control the system, a heat exchanger for the domestic hot water system and of course the building itself which is a one story, well insulated structure having a floor area of 1200 ft/sup 2/. A prototype collector was constructed and tested. Based on this experience, twenty collectors, containing 2860 four inch diameter solar cells, were constructed and installed on the building. Performance of the system was simulated using a TRNSYS-derived program, modified to accommodate PV/T panels and to include the particular components included in the selected system. Simulation of the performance showed that about 65 percent of the total annual energy needs of the building would be provided by the PV/T system. Of this total, about one half is produced at a time when it can be used in the building and one half must be sold back to the utility.

  8. Effect of formulas of titanoxide compositions on the photovoltaic characteristics of solar cells

    NASA Astrophysics Data System (ADS)

    Aimukhanov, A. K.; Ibrayev, N. Kh.; Serikov, T. M.

    2016-12-01

    The effect the chemical composition of semiconductor titanium compositions (titanium pastes) has on the photovoltaic characteristics of dye-sensitized solar cells is investigated. It is established that the efficiency of solar energy conversion by a photovoltaic cell made with Ti-nanooxide D paste is 5.3%, while that of one made with Degussa P25 paste is 4.7%. These data correlate with the specific surface and sorption ability of semiconductor films.

  9. Monolithic Parallel Tandem Organic Photovoltaic Cell with Transparent Carbon Nanotube Interlayer

    NASA Technical Reports Server (NTRS)

    Tanaka, S.; Mielczarek, K.; Ovalle-Robles, R.; Wang, B.; Hsu, D.; Zakhidov, A. A.

    2009-01-01

    We demonstrate an organic photovoltaic cell with a monolithic tandem structure in parallel connection. Transparent multiwalled carbon nanotube sheets are used as an interlayer anode electrode for this parallel tandem. The characteristics of front and back cells are measured independently. The short circuit current density of the parallel tandem cell is larger than the currents of each individual cell. The wavelength dependence of photocurrent for the parallel tandem cell shows the superposition spectrum of the two spectral sensitivities of the front and back cells. The monolithic three-electrode photovoltaic cell indeed operates as a parallel tandem with improved efficiency.

  10. Monolithic Parallel Tandem Organic Photovoltaic Cell with Transparent Carbon Nanotube Interlayer

    NASA Technical Reports Server (NTRS)

    Tanaka, S.; Mielczarek, K.; Ovalle-Robles, R.; Wang, B.; Hsu, D.; Zakhidov, A. A.

    2009-01-01

    We demonstrate an organic photovoltaic cell with a monolithic tandem structure in parallel connection. Transparent multiwalled carbon nanotube sheets are used as an interlayer anode electrode for this parallel tandem. The characteristics of front and back cells are measured independently. The short circuit current density of the parallel tandem cell is larger than the currents of each individual cell. The wavelength dependence of photocurrent for the parallel tandem cell shows the superposition spectrum of the two spectral sensitivities of the front and back cells. The monolithic three-electrode photovoltaic cell indeed operates as a parallel tandem with improved efficiency.

  11. Re-Defining Photovoltaic Efficiency Through Molecule Scale Control. Final Report

    SciTech Connect

    Yardley, James T.

    2015-04-30

    The direct conversion of sunlight into electricity represents one of the most important general means for sustainable energy production. Most modern photovoltaic cells are based on some form of semiconductor material such as silicon that is described by a characteristic energy or ''bandgap''. For solar rays with photon energy lower than the bandgap no absorption occurs and thus no energy is generated. For solar rays with photon energy greater than the bandgap, light may be absorbed to create a pair of electrical charges but only one bandgap of energy is created, leaving any additional energy lost as heat. Thus low bandgap materials can use a great part of the spectrum but can lose much of that energy; high bandgap materials fail to capture much of the spectrum. Thus there is a limit to the efficiency of such a solar cell that turns out to be about 32%. This limit is known as the Shockely-Queisser Limit. The Columbia EFRC program is dedicated to exploration of concepts that in principle can provide for efficiencies beyond this limit. One concept that this EFRC has explored for enhancing the efficiency of solar photovoltaic cells is called “Singlet Fission.” In this concept the absorption of light rays with photon energy at least twice the value of the basic bandgap for the system can produce two pairs of electrical charge carriers. If properly implemented this in principle can significantly reduce the energy lost as heat and give rise to solar cell efficiencies greater than the Shockley-Queisser limit. The problem is that there are virtually no materials that can undergo this process effectively. We have developed new materials that have demonstrated singlet fission efficiencies of almost 100%. We understand how these materials work and we have learned how to design many more systems in the future. So far we have only demonstrated the basic capability for efficient singlet fission. Much more work will be required to design and engineer specific materials that

  12. Development of wide-band gap indium gallium nitride solar cells for high-efficiency photovoltaics

    NASA Astrophysics Data System (ADS)

    Jani, Omkar K.

    lowered. Subsequent generations of solar cell designs involve an evolutionary approach to enhance the open-circuit voltage and internal quantum efficiency of the solar cell. The suitability of p-type InGaN with band gaps as low as 2.5 eV is established by incorporating in a solar cell and measuring an open-circuit voltage of 2.1 V. Second generation InGaN solar cell design involving a 2.9 eV InGaN p-n junction sandwiched between p- and n-GaN layers yields internal quantum efficiencies as high as 50%; while sixth generation devices utilizing the novel n-GaN strained window-layer enhance the open circuit voltage of a 2.9 eV InGaN solar cell to 2 V. Finally, key aspects to further InGaN solar cell research, including integration of various designs, are recommended to improve the efficiency of InGaN solar cells. These results establish the potential of III-nitrides in ultra-high efficiency photovoltaics.

  13. Spectral splitting photovoltaics using perovskite and wideband dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Kinoshita, Takumi; Nonomura, Kazuteru; Joong Jeon, Nam; Giordano, Fabrizio; Abate, Antonio; Uchida, Satoshi; Kubo, Takaya; Seok, Sang Il; Nazeeruddin, Mohammad Khaja; Hagfeldt, Anders; Grätzel, Michael; Segawa, Hiroshi

    2015-11-01

    The extension of the light absorption of photovoltaics into the near-infrared region is important to increase the energy conversion efficiency. Although the progress of the lead halide perovskite solar cells is remarkable, and high conversion efficiency of >20% has been reached, their absorption limit on the long-wavelength side is ~800 nm. To further enhance the conversion efficiency of perovskite-based photovoltaics, a hybridized system with near-infrared photovoltaics is a useful approach. Here we report a panchromatic sensitizer, coded DX3, that exhibits a broad response into the near-infrared, up to ~1100 nm, and a photocurrent density exceeding 30 mA cm-2 in simulated air mass 1.5 standard solar radiation. Using the DX3-based dye-sensitized solar cell in conjunction with a perovskite cell that harvests visible light, the hybridized mesoscopic photovoltaics achieved a conversion efficiency of 21.5% using a system of spectral splitting.

  14. Understanding the Photovoltaic Performance of Perovskite-Spirobifluorene Solar Cells.

    PubMed

    Song, Zhen; Liu, Jiang; Wang, Gang; Zuo, Wentao; Liao, Cheng; Mei, Jun

    2017-08-23

    Lead halide perovskite solar cells with remarkable power conversion efficiency have attracted much attention in recent years. However, there still exist many problems with their use that are not completely understood, and further studies are needed. Herein, the hole-transport layer dependence of the photovoltaic performance of perovskite solar cells is investigated in detail. It is found that devices freshly prepared using pristine 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD) and Li-doped spiro-OMeTAD as hole-transport layers exhibit S-shaped current density-voltage curves with poor fill factors. The devices show progressively improved fill factors and efficiencies upon exposure to air, which is attributed to air-induced conductivity improvement in the spiro-OMeTAD layer. After introducing a cobalt salt dopant (FK209) into the spiro-OMeTAD layer, the corresponding devices show remarkable performance without the need of air exposure. These results confirm that the dopant not only increases the conductivity of spiro-OMeTAD layer, but also tunes the surface potential, which helps to improve charge transport and reduce the recombination loss. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. US photovoltaic patents: 1991--1993

    SciTech Connect

    Pohle, L

    1995-03-01

    This document contains US patents on terrestrial photovoltaic (PV) power applications, including systems, components, and materials as well as manufacturing and support functions. The patent entries in this document were issued from 1991 to 1993. The entries were located by searching USPA, the database of the US Patent Office. The final search retrieved all patents under the class ``Batteries, Thermoelectric and Photoelectric`` and the subclasses ``Photoelectric,`` ``Testing,`` and ``Applications.`` The search also located patents that contained the words ``photovoltaic(s)`` or ``solar cell(s)`` and their derivatives. After the initial list was compiled, most of the patents on the following subjects were excluded: space photovoltaic technology, use of the photovoltaic effect for detectors, and subjects only peripherally concerned with photovoltaic. Some patents on these three subjects were included when ft appeared that those inventions might be of use in terrestrial PV power technologies.

  16. Enhancement of photovoltaic cell performance using periodic triangular gratings

    NASA Astrophysics Data System (ADS)

    Bordatchev, Evgueni; Tauhiduzzaman, Mohammed; Dey, Rajat

    2014-01-01

    The solar energy industry strives to produce more efficient and yet cost effective solar panels each consisting of an array of photovoltaic (PV) cells. The goal of this study was to enhance the performance of PV cells through increasing the cells' optical efficiency defined as a percentage of surface incident light that reaches the PV material. This was achieved through the reduction of waveguide decoupling loss and Fresnel reflection losses by integrating specific nonimaging micro-optical structures on the top surface of existing PV cells. Due to this integration, optical efficiency and performance were increased through the enhancement of light trapping, light guiding, and in-coupling functionalities. Periodic triangular gratings (PTGs) were designed, nonsequentially modeled, optimized, and fabricated in polydimethylsiloxane as proposed micro-optical structures. Then the performance of PV cells with and without integrated PTGs was evaluated and compared. Initial optical simulation results show that an original PV cell (without PTG) exhibits an average optical efficiency of 32.7% over a range of incident light angles between 15 and 90 deg. Integration of the PTG allows the capture of incoming sunlight by total internal reflection (TIR), whence it is reflected back onto the PV cell for multiple consecutive chances for absorption and PV conversion. Geometry of the PTG was optimized with respect to an angle of light incidence of {15, 30, 45, 60, 75, 90} deg. Optical efficiency of the geometrically optimized PTGs was then analyzed under the same set of incident light angles and a maximum optical efficiency of 54.1% was observed for a PV cell with integrated PTG optimized at 90 deg. This is a 53.3% relative improvement in optical performance when compared to an original PV cell. Functional PTG prototypes were then fabricated with optical surface quality (below 10 nm Ra) and integrated with PV cells demonstrating an increase in maximum power by 1.08 mW/cm (7

  17. Data base on batteries, power-conditioning equipment, and photovoltaic arrays. Final report

    SciTech Connect

    Podder, A; Kapner, M; Morse, T

    1981-02-01

    The objective of this study was to compile an up-to-date comprehensive data base for research, design, and development of photovoltaic systems, primarily in the areas of applications and battery technology, and secondarily in the area of power conditioning and photovoltaic array technology. This volume contains the data base used to develop the end-use scenarios and identify the R and D needed for batteries to be used in photovoltaic power systems. In addition to its specific application to the present study, this data base is intended to provide state-of-the-art information to manufacturers of the various components of photovoltaic power systems, system designers, and researchers in this field. An extensive literature search was conducted to obtain technical data on batteries, power conditioners, and photovoltaic arrays. The data obtained from published technical literature and direct communication with manufacturers and developers are compiled. Principles of operation, types of systems, performance characteristics, test data, and cost data are included for each of the components. (WHK)

  18. Energy distribution design on the photovoltaic cell array of the SSPS-OMEGA concept

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Zhang, Yiqun; Fan, Guanheng; Wang, Dongxu; Li, Xun

    2017-05-01

    Solar energy collection and conversion is of great significance to the power transmission of the Space Solar Power Station (SSPS), and has influences on the overall system, technologically and economically. For the proposed SSPS-OMEGA concept, the original conceptual design had non-uniform energy distribution and excessive energy density in local areas, which would cause decreases in its optical and electric performance. Aiming at this point, firstly, this paper evaluates the optical performance of the OMEGA concept via ray trace technique. Secondly, the generatrix geometry design of the photovoltaic (PV) cell array based on Bézier curve is carried out to obtain optimal optical performance available for efficient response to sunrays. After that numerical examples achieve good collection efficiency and suitable energy distribution. Finally, modular construction for the main concentrator and its influence on optical performance are investigated. Moreover, the effect of the orbital motion and tracking error are analyzed to provide reference for the realization of the OMEGA.

  19. Space Photovoltaic Concentrator Using Robust Fresnel Lenses, 4-Junction Cells, Graphene Radiators, and Articulating Receivers

    NASA Technical Reports Server (NTRS)

    O'Neill, Mark; McDanal, A. J.; Brandhorst, Henry; Spence, Brian; Iqbal, Shawn; Sharps, Paul; McPheeters, Clay; Steinfeldt, Jeff; Piszczor, Michael; Myers, Matt

    2016-01-01

    At the 42nd PVSC, our team presented recent advances in our space photovoltaic concentrator technology. These advances include more robust Fresnel lenses for optical concentration, more thermally conductive graphene radiators for waste heat rejection, improved color-mixing lens technology to minimize chromatic aberration losses with 4-junction solar cells, and an articulating photovoltaic receiver enabling single-axis sun-tracking, while maintaining a sharp focal line despite large beta angles of incidence. In the past year, under a NASA Phase II SBIR program, our team has made much additional progress in the development of this new space photovoltaic concentrator technology, as described in this paper.

  20. High-Performance GaAs Nanowire Solar Cells for Flexible and Transparent Photovoltaics.

    PubMed

    Han, Ning; Yang, Zai-xing; Wang, Fengyun; Dong, Guofa; Yip, SenPo; Liang, Xiaoguang; Hung, Tak Fu; Chen, Yunfa; Ho, Johnny C

    2015-09-16

    Among many available photovoltaic technologies at present, gallium arsenide (GaAs) is one of the recognized leaders for performance and reliability; however, it is still a great challenge to achieve cost-effective GaAs solar cells for smart systems such as transparent and flexible photovoltaics. In this study, highly crystalline long GaAs nanowires (NWs) with minimal crystal defects are synthesized economically by chemical vapor deposition and configured into novel Schottky photovoltaic structures by simply using asymmetric Au-Al contacts. Without any doping profiles such as p-n junction and complicated coaxial junction structures, the single NW Schottky device shows a record high apparent energy conversion efficiency of 16% under air mass 1.5 global illumination by normalizing to the projection area of the NW. The corresponding photovoltaic output can be further enhanced by connecting individual cells in series and in parallel as well as by fabricating NW array solar cells via contact printing showing an overall efficiency of 1.6%. Importantly, these Schottky cells can be easily integrated on the glass and plastic substrates for transparent and flexible photovoltaics, which explicitly demonstrate the outstanding versatility and promising perspective of these GaAs NW Schottky photovoltaics for next-generation smart solar energy harvesting devices.

  1. Photovoltaic Cz Silicon Module Improvements; Final Subcontract Report, 9 November 1995 - 8 November 1998

    SciTech Connect

    T. L. Jester.

    1999-06-17

    This report describes work that focused on reducing the cost per watt of Cz silicon photovoltaic modules under Siemens Solar Industries' (SSI) DOE/NREL Photovoltaic Manufacturing Technology (PVMaT) 4A subcontract. SSI researchers deployed new module designs, realized improvements in yield of more than 25%, and implemented statistical process control (SPC). They have described yield improvements in detail and reported on the deployment of SPC in critical process steps. The sum of all improvements resulted in a greater than 17% cost per watt reduction in manufacturing.

  2. Realizing Efficient Energy Harvesting from Organic Photovoltaic Cells

    NASA Astrophysics Data System (ADS)

    Zou, Yunlong

    Organic photovoltaic cells (OPVs) are emerging field of research in renewable energy. The development of OPVs in recent years has made this technology viable for many niche applications. In order to realize widespread application however, the power conversion efficiency requires further improvement. The efficiency of an OPV depends on the short-circuit current density (JSC), open-circuit voltage (VOC) and fill factor (FF). For state-of-the-art devices, JSC is mostly optimized with the application of novel low-bandgap materials and a bulk heterojunction device architecture (internal quantum efficiency approaching 100%). The remaining limiting factors are the low VOC and FF. This work focuses on overcoming these bottlenecks for improved efficiency. Temperature dependent measurements of device performance are used to examine both charge transfer and exciton ionization process in OPVs. The results permit an improved understanding of the intrinsic limit for VOC in various device architectures and provide insight on device operation. Efforts have also been directed at engineering device architecture for optimized FF, realizing a very high efficiency of 8% for vapor deposited small molecule OPVs. With collaborators, new molecules with tailored desired energy levels are being designed for further improvements in efficiency. A new type of hybrid organic-inorganic perovskite material is also included in this study. By addressing processing issues and anomalous hysteresis effects, a very high efficiency of 19.1% is achieved. Moving forward, topics including engineering film crystallinity, exploring tandem architectures and understanding degradation mechanisms will further push OPVs toward broad commercialization.

  3. Photovoltaic Cell Having A P-Type Polycrystalline Layer With Large Crystals

    DOEpatents

    Albright, Scot P.; Chamberlin, Rhodes R.

    1996-03-26

    A photovoltaic cell has an n-type polycrystalline layer and a p-type polycrystalline layer adjoining the n-type polycrystalline layer to form a photovoltaic junction. The p-type polycrystalline layer comprises a substantially planar layer portion having relatively large crystals adjoining the n-type polycrystalline layer. The planar layer portion includes oxidized impurities which contribute to obtainment of p-type electrical properties in the planar layer portion.

  4. US Coast Guard participation in the Federal Photovoltaic Utilization Program. Final technical report

    SciTech Connect

    Not Available

    1986-03-05

    The US Coast Guard began investigating solar photovoltaic arrays as power sources for marine aids to navigation in 1974. After several years of research and development effort the decision was made to convert the power systems of over 10,000 minor aids to navigation from expensive and environmentally hazardous primary batteries to solar power.

  5. US Coast Guard participation in the Federal Photovoltaic Utilization Program. Final Technical report

    SciTech Connect

    Not Available

    1986-03-05

    The US Coast Guard began investigating solar photovoltaic arrays as power sources for marine aids to navigation in 1974. After several years of research and development effort, the decision was made to convert the power systems of over 10,000 minor aids to navigation from expensive and environmentally hazardous primary batteries to solar power.

  6. Establishment of a photovoltaic laboratory at the University of Lowell: Final report

    SciTech Connect

    Not Available

    1989-01-01

    The goal of this project was to move laboratory equipment from the MIT Lincoln Laboratory and install a photovoltaic systems laboratory at the University of Lowell. The project was later extended twice: first to include initiation of education and evaluation projects, and second to work with Enersol Associates to produce a report on rural electrification in the Dominican Republic.

  7. Photovoltaic materials.

    PubMed

    Perez-Albuerne, E A; Tyan, Y S

    1980-05-23

    Solid-state photovoltaic cells are feasible devices for converting solar energy directly to electricity. Recent cost reductions have spurred an incipient industry, but further advances in materials science and technology are needed before photovoltaic cells can compete with other sources for the supply of large amounts of energy. In this article energy loss mechanisms in solid-state photovoltaic cells are examined and related to materials properties. Various systems under development are reviewed which illustrate some key concepts, opportunities, and problems of this most promising emerging technology. Areas where contributions from innovative materials research would have a significant effect are also indicated.

  8. Lithium Ion Cell Development for Photovoltaic Energy Storage Applications

    SciTech Connect

    Babinec, Susan

    2012-02-08

    The overall project goal is to reduce the cost of home and neighborhood photovoltaic storage systems by reducing the single largest cost component the energy storage cells. Solar power is accepted as an environmentally advantaged renewable power source. Its deployment in small communities and integrated into the grid, requires a safe, reliable and low cost energy storage system. The incumbent technology of lead acid cells is large, toxic to produce and dispose of, and offer limited life even with significant maintenance. The ideal PV storage battery would have the safety and low cost of lead acid but the performance of lithium ion chemistry. Present lithium ion batteries have the desired performance but cost and safety remain the two key implementation barriers. The purpose of this project is to develop new lithium ion cells that can meet PVES cost and safety requirements using A123Systems phosphate-based cathode chemistries in commercial PHEV cell formats. The cost target is a cell design for a home or neighborhood scale at <$25/kWh. This DOE program is the continuation and expansion of an initial MPSC (Michigan Public Service Commission) program towards this goal. This program further pushes the initial limits of some aspects of the original program even lower cost anode and cathode actives implemented at even higher electrode loadings, and as well explores new avenues of cost reduction via new materials specifically our higher voltage cathode. The challenge in our materials development is to achieve parity in the performance metrics of cycle life and high temperature storage, and to produce quality materials at the production scale. Our new cathode material, M1X, has a higher voltage and so requires electrolyte reformulation to meet the high temperature storage requirements. The challenge of thick electrode systems is to maintain adequate adhesion and cycle life. The composite separator has been proven in systems having standard loading electrodes; the challenge

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

    NASA Astrophysics Data System (ADS)

    Aeberhard, Urs

    2017-04-01

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

  10. A study of potential high band-gap photovoltaic materials for a two step photon intermediate technique in fission energy conversion. Final report

    SciTech Connect

    Prelas, M.A.

    1996-01-24

    This report describes progress made to develop a high bandgap photovoltaic materials for direct conversion to electricity of excimer radiation produced by fission energy pumped laser. This report summarizes the major achievements in sections. The first section covers n-type diamond. The second section covers forced diffusion. The third section covers radiation effects. The fourth section covers progress in Schottky barrier and heterojunction photovoltaic cells. The fifth section covers cell and reactor development.

  11. High-efficiency one-sun photovoltaic module demonstration using solar-grade CZ silicon. Final report

    SciTech Connect

    Gee, J.M.

    1996-10-01

    This work was performed jointly by Sandia National Laboratories (Albuquerque, NM) and Siemens Solar Industries (Camarillo, CA) under a Cooperative Research and Development Agreement (CRADA 1248). The work covers the period May 1994 to March 1996. The purpose of the work was to explore the performance potential of commercial, photovoltaic-grade Czochralski (Cz) silicon, and to demonstrate this potential through fabrication of high-efficiency cells and a module. Fabrication of the module was omitted in order to pursue further development of advanced device structures. The work included investigation of response of the material to various fabrication processes, development of advanced cell structures using the commercial material, and investigation of the stability of Cz silicon solar cells. Some important achievements of this work include the following: post-diffusion oxidations were found to be a possible source of material contamination; bulk lifetimes around 75 pts were achieved; efficiencies of 17.6% and 15.7% were achieved for large-area cells using advanced cell structures (back-surface fields and emitter wrap-through); and preliminary investigations into photodegradation in Cz silicon solar cells found that oxygen thermal donors might be involved. Efficiencies around 20% should be possible with commercial, photovoltaic-grade silicon using properly optimized processes and device structures.

  12. Impact of the organic halide salt on final perovskite composition for photovoltaic applications

    SciTech Connect

    Moore, David T.; Sai, Hiroaki; Wee Tan, Kwan; Estroff, Lara A.; Wiesner, Ulrich

    2014-08-01

    The methylammonium lead halide perovskites have shown significant promise as a low-cost, second generation, photovoltaic material. Despite recent advances, however, there are still a number of fundamental aspects of their formation as well as their physical and electronic behavior that are not well understood. In this letter we explore the mechanism by which these materials crystallize by testing the outcome of each of the reagent halide salts. We find that components of both salts, lead halide and methylammonium halide, are relatively mobile and can be readily exchanged during the crystallization process when the reaction is carried out in solution or in the solid state. We exploit this fact by showing that the perovskite structure is formed even when the lead salt's anion is a non-halide, leading to lower annealing temperature and time requirements for film formation. Studies into these behaviors may ultimately lead to improved processing conditions for photovoltaic films.

  13. EH AND S ANALYSIS OF DYE-SENSITIZED PHOTOVOLTAIC SOLAR CELL PRODUCTION.

    SciTech Connect

    BOWERMAN,B.; FTHENAKIS,V.

    2001-10-01

    Photovoltaic solar cells based on a dye-sensitized nanocrystalline titanium dioxide photoelectrode have been researched and reported since the early 1990's. Commercial production of dye-sensitized photovoltaic solar cells has recently been reported in Australia. In this report, current manufacturing methods are described, and estimates are made of annual chemical use and emissions during production. Environmental, health and safety considerations for handling these materials are discussed. This preliminary EH and S evaluation of dye-sensitized titanium dioxide solar cells indicates that some precautions will be necessary to mitigate hazards that could result in worker exposure. Additional information required for a more complete assessment is identified.

  14. Waste reduction options for manufacturers of copper indium diselenide photovoltaic cells

    SciTech Connect

    DePhillips, M.P.; Fthenakis, V.M.; Moskowitz, P.D.

    1994-03-01

    This paper identifies general waste reduction concepts and specific waste reduction options to be used in the production of copper indium diselenide (CIS) photovoltaic cells. A general discussion of manufacturing processes used for the production of photovoltaic cells is followed by a description of the US Environmental Protection Agency (EPA) guidelines for waste reduction (i.e., waste minimization through pollution prevention). A more specific discussion of manufacturing CIS cells is accompanied by detailed suggestions regarding waste minimization options for both inputs and outputs for ten stages of this process. Waste reduction from inputs focuses on source reduction and process changes, and reduction from outputs focuses on material reuse and recycling.

  15. EH AND S ANALYSIS OF DYE-SENSITIZED PHOTOVOLTAIC SOLAR CELL PRODUCTION.

    SciTech Connect

    BOWERMAN,B.; FTHENAKIS,V.

    2001-10-01

    Photovoltaic solar cells based on a dye-sensitized nanocrystalline titanium dioxide photoelectrode have been researched and reported since the early 1990's. Commercial production of dye-sensitized photovoltaic solar cells has recently been reported in Australia. In this report, current manufacturing methods are described, and estimates are made of annual chemical use and emissions during production. Environmental, health and safety considerations for handling these materials are discussed. This preliminary EH and S evaluation of dye-sensitized titanium dioxide solar cells indicates that some precautions will be necessary to mitigate hazards that could result in worker exposure. Additional information required for a more complete assessment is identified.

  16. Charge extraction from nanostructured hybrid organic-inorganic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Goh, Chiatzun

    Conjugated polymers are attractive for use in photovoltaic (PV) cells because they are highly absorptive, their absorption spectrum can be tuned to match various regions of the solar spectrum and their solubility in common solvents enables the use of low-cost printing technique to mass produce PV panels. Photoexcitation of conjugated polymers forms excitons, which are bound electron-hole pairs. In order to convert these excitons into free carriers, the polymers have to be blended with an electron acceptor in close promixity of ˜10 nm. The charge transfer process at the donor-acceptor interface provides the necessary driving force to split excitons, while the close proximity guarantees excitons reaching an interface before decaying. Once the carriers are split, they have to be transported to their respective electrodes before recombining. Ordered nanostructured titania (TiO2) matrix infiltrated with conjugated polymers is a promising acceptor-donor system, which can potentially meet these requirements. In this work, several optimizations are shown to be essential for increasing the performance of TiO2/polymer cells. First, we measure the hole mobility of poly(3-hexylthiophene) (P3HT) in a thin film diode in the space-charge limited regime. We show that the mobility increases with the polymer molecular weight and can be correlated to the film morphology. The anisotropy in P3HT chain packing suggests that its diode mobility of 10-4 cm 2/Vs can be further enhanced upon chain alignment in straight nanopores. Second, we investigate the use of molecular surface modification to control the interfacial energetics and charge transfer dynamics. By introducing dipoles at the TiO2/P3HT interface, the interfacial energy offset can be changed resulting in a concomitant change in the open circuit voltage. In addition, certain modifiers improve exciton harvesting by mediating charge transfer from the polymer to TiO2. We further show that the use of an amphiphilic molecule

  17. Surrogate Final Technical Report for "Solar: A Photovoltaic Manufacturing Development Facility"

    SciTech Connect

    Farrar, Paul

    2014-06-27

    The project goal to create a first-of-a-kind crystalline Silicon (c-Si) photovoltaic (PV) Manufacturing & Technology Development Facility (MDF) that will support the growth and maturation of a strong domestic PV manufacturing industry, based on innovative and differentiated technology, by ensuring industry participants can, in a timely and cost-effective manner, access cutting-edge manufacturing equipment and production expertise needed to accelerate the transition of innovative technologies from R&D into manufacturing.

  18. Photovoltaic manufacturing cost analysis: a required-price approach. Volume 2. Appendixes. Final report

    SciTech Connect

    Wright, S.R.; Champagne, P.T.; Brookshire, K.L.

    1986-09-01

    These appendices contain supporting information to aid in interpreting a comparative assessment of the required module price drivers for five different processes of producing photovoltaic modules. They include: definition of the IMCAP model, base case simulation results, cost catalog, and definition of the dendritic web process, the Czochralski process, single-junction amorphous silicon process, tandem-junction amorphous silicon process, and 500X concentrator process. (LEW)

  19. Ecotoxicological assessment of solar cell leachates: Copper indium gallium selenide (CIGS) cells show higher activity than organic photovoltaic (OPV) cells.

    PubMed

    Brun, Nadja Rebecca; Wehrli, Bernhard; Fent, Karl

    2016-02-01

    Despite the increasing use of photovoltaics their potential environmental risks are poorly understood. Here, we compared ecotoxicological effects of two thin-film photovoltaics: established copper indium gallium selenide (CIGS) and organic photovoltaic (OPV) cells. Leachates were produced by exposing photovoltaics to UV light, physical damage, and exposure to environmentally relevant model waters, representing mesotrophic lake water, acidic rain, and seawater. CIGS cell leachates contained 583 μg L(-1) molybdenum at lake water, whereas at acidic rain and seawater conditions, iron, copper, zinc, molybdenum, cadmium, silver, and tin were present up to 7219 μg L(-1). From OPV, copper (14 μg L(-1)), zinc (87 μg L(-1)) and silver (78 μg L(-1)) leached. Zebrafish embryos were exposed until 120 h post-fertilization to these extracts. CIGS leachates produced under acidic rain, as well as CIGS and OPV leachates produced under seawater conditions resulted in a marked hatching delay and increase in heart edema. Depending on model water and solar cell, transcriptional alterations occurred in genes involved in oxidative stress (cat), hormonal activity (vtg1, ar), metallothionein (mt2), ER stress (bip, chop), and apoptosis (casp9). The effects were dependent on the concentrations of cationic metals in leachates. Addition of ethylenediaminetetraacetic acid protected zebrafish embryos from morphological and molecular effects. Our study suggests that metals leaching from damaged CIGS cells, may pose a potential environmental risk. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Printing Processes Used to Manufacture Photovoltaic Solar Cells

    ERIC Educational Resources Information Center

    Rardin, Tina E.; Xu, Renmei

    2011-01-01

    There is a growing need for renewable energy sources, and solar power is a good option in many instances. Photovoltaic solar panels are now being manufactured via various methods, and different printing processes are being incorporated into the manufacturing process. Screen printing has been used most prevalently in the printing process to make…

  1. Method for producing textured substrates for thin-film photovoltaic cells

    DOEpatents

    Lauf, Robert J.

    1994-01-01

    The invention pertains to the production of ceramic substrates used in the manufacture of thin-film photovoltaic cells used for directly converting solar energy to electrical energy. Elongated ribbon-like sheets of substrate precursor containing a mixture of ceramic particulates, a binder, and a plasticizer are formed and then while green provided with a mechanically textured surface region used for supporting the thin film semiconductor of the photovoltaic cell when the sheets of the substrate precursor are subsequently cut into substrate-sized shapes and then sintered. The textured surface pattern on the substrate provides enhanced light trapping and collection for substantially increasing the solar energy conversion efficiency of thin-film photovoltaic cells.

  2. Method for producing textured substrates for thin-film photovoltaic cells

    DOEpatents

    Lauf, R.J.

    1994-04-26

    The invention pertains to the production of ceramic substrates used in the manufacture of thin-film photovoltaic cells used for directly converting solar energy to electrical energy. Elongated ribbon-like sheets of substrate precursor containing a mixture of ceramic particulates, a binder, and a plasticizer are formed and then while green provided with a mechanically textured surface region used for supporting the thin film semiconductor of the photovoltaic cell when the sheets of the substrate precursor are subsequently cut into substrate-sized shapes and then sintered. The textured surface pattern on the substrate provides enhanced light trapping and collection for substantially increasing the solar energy conversion efficiency of thin-film photovoltaic cells. 4 figures.

  3. Method for producing textured substrates for thin-film photovoltaic cells

    DOEpatents

    Lauf, Robert J.

    1996-01-01

    The invention pertains to the production of ceramic substrates used in the manufacture of thin-film photovoltaic cells used for directly converting solar energy to electrical energy. Elongated ribbon-like sheets of substrate precursor containing a mixture of ceramic particulates, a binder, and a plasticizer are formed and then while green provided with a mechanically textured surface region used for supporting the thin film semiconductor of the photovoltaic cell when the sheets of the substrate precursor are subsequently cut into substrate-sized shapes and then sintered. The textured surface pattern on the substrate provides enhanced light trapping and collection for substantially increasing the, solar energy conversion efficiency of thin-film photovoltaic cells.

  4. Method for producing textured substrates for thin-film photovoltaic cells

    DOEpatents

    Lauf, R.J.

    1996-04-02

    The invention pertains to the production of ceramic substrates used in the manufacture of thin-film photovoltaic cells used for directly converting solar energy to electrical energy. Elongated ribbon-like sheets of substrate precursor containing a mixture of ceramic particulates, a binder, and a plasticizer are formed and then while green provided with a mechanically textured surface region used for supporting the thin film semiconductor of the photovoltaic cell when the sheets of the substrate precursor are subsequently cut into substrate-sized shapes and then sintered. The textured surface pattern on the substrate provides enhanced light trapping and collection for substantially increasing the, solar energy conversion efficiency of thin-film photovoltaic cells. 4 figs.

  5. Efficient small-molecule photovoltaic cells using a crystalline diindenoperylene film as a nanostructured template.

    PubMed

    Zhou, Ying; Taima, Tetsuya; Kuwabara, Takayuki; Takahashi, Kohshin

    2013-11-13

    A cascade-type small-molecule organic photovoltaic cell using a crystalline diindenoperylene film as a nanostructured template is demonstrated. This cell architecture simultaneously realizes organic nanostructure and cascade energy concepts, which significantly improves the photocurrent generation and fill factor, leading to a power conversion efficiency of 5.2±0.3%.

  6. Photovoltaic Engineering Testbed: A Facility for Space Calibration and Measurement of Solar Cells on the International Space Station

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Bailey, Sheila G.; Jenkins, Phillip; Sexton, J. Andrew; Scheiman, David; Christie, Robert; Charpie, James; Gerber, Scott S.; Johnson, D. Bruce

    2001-01-01

    The Photovoltaic Engineering Testbed ("PET") is a facility to be flown on the International Space Station to perform calibration, measurement, and qualification of solar cells in the space environment and then returning the cells to Earth for laboratory use. PET will allow rapid turnaround testing of new photovoltaic technology under AM0 conditions.

  7. Current topics in photovoltaics

    SciTech Connect

    Coutts, T.J. ); Meakin, J.D. . Inst. of Energy Conversion)

    1990-01-01

    This book contains papers on current research in photovoltaics. Areas include: outdoor spectral odor radiation variations and their relationship to photovoltaic device performance, numerical modeling for analysis and design of solar cells, radiation damage mechanisms in GaAs and Si solar cells, and health and safety issues in the manufacturing of photovoltaic cells.

  8. Photovoltaic hysteresis and its ramifications for concentrator solar cell design and diagnostics

    NASA Astrophysics Data System (ADS)

    Gordon, Jeffrey M.; Katz, Eugene A.; Tassew, Wondesen; Feuermann, Daniel

    2005-02-01

    We report the observation of a photovoltaic effect with pronounced hysteresis. The phenomenon derives from the sharp transition in the dominant mode of electron transport in the tunnel diodes that regulate multijunction solar cells, and is only observable at high flux. These results emerged from measurements of cell current-voltage characteristics performed with miniature fiber-optic solar concentrators that can deliver flux levels up to 10 000 times that of ambient sunlight in a highly localized fashion. The ramifications of our findings for photovoltaic design, diagnostics, and performance are addressed, and a nondestructive determination of the peak and valley threshold current densities of tunnel diodes is presented.

  9. Diarylindenotetracenes via a selective cross-coupling/C-H functionalization: electron donors for organic photovoltaic cells.

    PubMed

    Gu, Xingxian; Luhman, Wade A; Yagodkin, Elisey; Holmes, Russell J; Douglas, Christopher J

    2012-03-16

    A direct synthesis of new donor materials for organic photovoltaic cells is reported. Diaryindenotetracenes were synthesized utilizing a Kumada-Tamao-Corriu cross-coupling of peri-substituted tetrachlorotetracene with spontaneous indene annulation via C-H activation. Vacuum deposited planar heterojunction organic photovoltaic cells incorporating these molecules as electron donors exhibit power conversion efficiencies exceeding 1.5% with open-circuit voltages ranging from 0.7 to 1.1 V when coupled with C(60) as an electron acceptor.

  10. Designing a metallic nanoconcentrator for a lateral multijunction photovoltaic cell

    NASA Astrophysics Data System (ADS)

    Wang, Trudie; Peumans, Peter

    2011-06-01

    A lateral multijunction photovoltaic (PV) concept is introduced that explores the unique ability of plasmonic nanoantennas to locally concentrate optical energy and spectrally filter incoming light at the subwavelength level. This electromagnetic field enhancement near the localized plasmon resonance modes of the metallic nanoantennas can be used to selectively increase light absorption in semiconductor nanowires at specific spectral and spatial regions. In our geometry, we take advantage of the ring antenna's ability to excite two distinct plasmon modes in order to carry out spectral splitting and concentration of the electromagnetic field. A localized dipolar surface plasmon mode near the material resonance of the silver nanoantenna results from the ring behaving as an effective disk in the visible region and focuses the field on the external surface of the ring while a dipolar bonding resonance mode dependent on the coupling of modes excited on the inner and outer surface of the ring geometry in the near infrared (NIR) region focuses energy in the cavity of the ring. Using finite difference time domain (FDTD) simulations, we describe the basic mechanisms at work and demonstrate that the subwavelength ring antennas can couple incident light into semiconductor nanowires placed both inside and outside the ring through the two modes with minimal loss in the metal. The modes are used to laterally split different spectral regions of broadband incident light optimized to the material bandgap of the nanowires located in the regions of field enhancement to produce the lateral multijunction effect. We demonstrate that, for example, a ring antenna with both an internal diameter and a thickness of 40 nm can enhance absorption by 6x in the visible region for a 100 nm tall AlAs nanowire placed just outside the ring and by 380x in the NIR region for a geometrically similar GaAs nanowire placed inside the ring. Both enhancements occur just above the material band gaps of the

  11. Design and performance of the Georgia Tech Aquatic Center photovoltaic system. Final report

    SciTech Connect

    Rohatgi, A.; Begovic, M.; Long, R.; Ropp, M.; Pregelj, A.

    1996-12-31

    A building-integrated DC PV array has been constructed on the Georgia Tech campus. The array is mounted on the roof of the Georgia Tech Aquatic Center (GTAC), site of the aquatic events during the 1996 Paralympic and Olympic Games in Atlanta. At the time of its construction, it was the world`s largest roof-mounted photovoltaic array, comprised of 2,856 modules and rates at 342 kW. This section describes the electrical and physical layout of the PV system, and the associated data acquisition system (DAS) which monitors the performance of the system and collects measurements of several important meteorological parameters.

  12. Handbook of secondary storage batteries and charge regulators in photovoltaic systems. Final report

    SciTech Connect

    Not Available

    1981-08-01

    Solar photovoltaic systems often require battery subsystems to store reserve electrical energy for times of zero insolation. This handbook is designed to help the system designer make optimum choices of battery type, battery size and charge control circuits. Typical battery performance characteristics are summarized for four types of lead-acid batteries: pure lead, lead-calcium and lead-antimony pasted flat plate and lead-antimony tubular positive types. Similar data is also provided for pocket plate nickel cadmium batteries. Economics play a significant role in battery selection. Relative costs of each battery type are summarized under a variety of operating regimes expected for solar PV installations.

  13. Magnetic field effects in a polymer/fullerene blend photovoltaic cell

    NASA Astrophysics Data System (ADS)

    Jang, Hyuk-Jae; Basham, James I.; Gundlach, David J.; Richter, Curt A.

    Organic photovoltaic (OPV) systems based on blends of conjugated polymers and fullerene derivatives have shown great promise for low-cost and efficient photovoltaic applications. Recent findings suggest that a weak external magnetic field can disturb the spin configuration of excited states and subsequently change properties of OPV cells such as photocurrent. These changes are referred to as magnetic field effects (MFEs). In order to have a better understanding of the underlying mechanisms responsible for the MFEs in polymer/fullerene blend photovoltaic systems, we fabricated poly-3-hexylthiophene (P3HT):phenyl-C61-butyric acid methyl ester (PC61BM) cells and carried out photovoltaic device performance and impedance spectroscopy measurements with and without an externally applied magnetic field. A significant reduction in short circuit current (JSC) as well as open circuit voltage (VOC) was observed with an applied magnetic field of a 0.1 tesla compared to those measured without a magnetic field under the same intensity of illumination. Impedance spectroscopy data gives insights into the influence of an external magnetic field on charge generation and recombination near normal photovoltaic operating conditions.

  14. Design and fabrication of a rectenna system to be coupled to photovoltaic solar cells

    NASA Astrophysics Data System (ADS)

    Mossavat, Mazda

    Inkjet-printed metamaterials and nanotechnology enabled flexible antennas fabricated on glass or polyester substrates help in further absorption of transmitted radiation through photovoltaic solar cells. Using metamaterials processed by inkjet printing and diffusing it, for a rectenna system coupled with photovoltaic solar cells, as rectifying antenna, an antenna in system in tandem is created. Metamaterials are artificial materials engineered to have properties that may not be found in nature (negative refractive index). When used in an antenna, they increase gain. For efficient solar cell use, nanophotonics on the incident surface or metamaterials under it as a rectenna, can enhance voltage gain in cloudy or rainy condition, which in turn increases the overall efficiency and reduces the amount of material required, thereby cutting costs. Photovoltaic is a field of technology and research related to practical application of photovoltaic cells in producing electricity from light. Cells are described as photovoltaic cells when the light source is not necessarily sunlight but can be lamplight, artificial light, or any other source used for detecting light or other electromagnetic radiation at different light intensity and producing voltage. These can be, for example, infrared detectors, or detectors for measurement of light intensity. Conventional solar cell films are typically manufactured using expensive and slow manufacturing methods, which rely on high-temperature fabrication and finicky `vacuum deposition' processes for depositing solar materials onto substrates (III-V elements). The resultant products are simply too thick to allow for transparency. An important consideration in the development of a commercially viable solar powered cell is the glass substrate. The learning process and skills involved in developing the antenna below a solar cell is a great experience in theory and practice. My main effort will be to design and check performance of different

  15. Method for contact resistivity measurements on photovoltaic cells and cell adapted for such measurement

    NASA Technical Reports Server (NTRS)

    Burger, Dale R. (Inventor)

    1986-01-01

    A method is disclosed for scribing at least three grid contacts of a photovoltaic cell to electrically isolate them from the grid contact pattern used to collect solar current generated by the cell, and using the scribed segments for determining parameters of the cell by a combination of contact end resistance (CER) measurements using a minimum of three equally or unequally spaced lines, and transmission line modal (TLM) measurements using a minimum of four unequally spaced lines. TLM measurements may be used to determine sheet resistance under the contact, R.sub.sk, while CER measurements are used to determine contact resistivity, .rho..sub.c, from a nomograph of contact resistivity as a function of contact end resistance and sheet resistivity under the contact. In some cases, such as the case of silicon photovoltaic cells, sheet resistivity under the contact may be assumed to be equal to the known sheet resistance, R.sub.s, of the semiconductor material, thereby obviating the need for TLM measurements to determine R.sub.sk.

  16. Photovoltaic switching mechanism in lateral structure hybrid perovskite solar cells

    SciTech Connect

    Yuan, Yongbo; Chae, Jungseok; Shao, Yuchuan; Wang, Qi; Xiao, Zhengguo; Centrone, Andrea; Huang, Jinsong

    2015-06-05

    In this study, long range electromigration of methylammonium ions (MA+) in methyl ammonium lead tri-iodide (MAPbI3) film is observed directly using the photo­thermal induced resonance technique. The electromigration of MA+ leads to the formation of a lateral p-i-n structure, which is the origin of the switchable photovoltaic effect in MAPbI3 perovskite devices.

  17. Photovoltaic switching mechanism in lateral structure hybrid perovskite solar cells

    DOE PAGES

    Yuan, Yongbo; Chae, Jungseok; Shao, Yuchuan; ...

    2015-06-05

    In this study, long range electromigration of methylammonium ions (MA+) in methyl ammonium lead tri-iodide (MAPbI3) film is observed directly using the photo­thermal induced resonance technique. The electromigration of MA+ leads to the formation of a lateral p-i-n structure, which is the origin of the switchable photovoltaic effect in MAPbI3 perovskite devices.

  18. New N-Type Polymers for Organic Photovoltaics: Cooperative Research and Development Final Report, CRADA Number CRD-06-177

    SciTech Connect

    Olson, D.

    2014-08-01

    This CRADA will develop improved thin film organic solar cells using a new n-type semiconducting polymer. High efficiency photovoltaics (PVs) based on inorganic semiconductors have good efficiencies (up to 30%) but are extremely expensive to manufacture. Organic PV technology has the potential to overcome this problem through the use of high-throughput production methods like reel-to-reel printing on flexible substrates. Unfortunately, today's best organic PVs have only a few percent efficiency, a number that is insufficient for virtually all commercial applications. The limited choice of stable n-type (acceptor) organic semiconductor materials is one of the key factors that prevent the further improvement of organic PVs. TDA Research, Inc. (TDA) previously developed a new class of electron-deficient (n-type) conjugated polymers for use in organic light emitting diodes (OLEDs). During this project TDA in collaboration with the National Renewable Energy Laboratory (NREL) will incorporate these electron-deficient polymers into organic photovoltaics and investigate their performance. TDA Research, Inc. (TDA) is developing new materials and polymers to improve the performance of organic solar cells. Materials being developed at TDA include spin coated transparent conductors, charge injection layers, fullerene derivatives, electron-deficient polymers, and three-phase (fullerene/polythiophene/dye) active layer inks.

  19. Improvement of power conversion efficiency in photovoltaic-assisted UHF rectifiers by non-silicide technique applied to photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Kotani, Koji

    2015-04-01

    Non-silicide PV cell structures were successfully applied to the photovoltaic (PV)-assisted UHF rectifier, which is one example realization of the “synergistic ambient energy harvesting” concept. Silicide blocking of PV cell area was experimentally verified to be effective for increasing photo-generated bias voltage, which resulted in the improved power conversion efficiency (PCE) of the rectifier by enhanced VTH compensation effect. Increase in both transparency of light and quantum efficiency of PV cells obtained by eliminating silicide layer affects the PCE improvement almost equally. 25.8% of PCE was achieved under the conditions of an RF input power of -20 dBm, a frequency of 920 MHz, an output load of 47 kΩ, and a typical indoor light irradiance level of 1 W/m2. In addition, when the non-silicide PV cell technique was applied to the voltage-boosted PV-cell structures, 32.1% peak PCE was achieved at 10 W/m2.

  20. Interplay of Nanoscale, Hybrid P3HT/ZTO Interface on Optoelectronics and Photovoltaic Cells.

    PubMed

    Lai, Jian-Jhong; Li, Yu-Hsun; Feng, Bo-Rui; Tang, Shiow-Jing; Jian, Wen-Bin; Fu, Chuan-Min; Chen, Jiun-Tai; Wang, Xu; Lee, Pooi See

    2017-09-13

    Photovoltaic effects in poly(3-hexylthiophene-2,5-diyl) (P3HT) have attracted much attention recently. Here, natively p-type doped P3HT nanofibers and n-type doped zinc tin oxide (ZTO) nanowires are used for making not only field-effect transistors (FETs) but also p-n nanoscale diodes. The hybrid P3HT/ZTO p-n heterojunction shows applications in many directions, and it also facilitates the investigation of photoelectrons and photovoltaic effects on the nanoscale. As for applications, the heterojunction device shows a simultaneously high on/off ratio of n- and p-type FETs, gatable p-n junction diodes, tristate buffer devices, gatable photodetectors, and gatable solar cells. On the other hand, P3HT nanofibers are taken as a photoactive layer and the role played by the p-n heterojunction in the photoelectric and photovoltaic effects is investigated. It is found that the hybrid P3HT/ZTO p-n heterojunction assists in increasing photocurrents and enhancing photovoltaic effects. Through the controllable gating of the heterojunction, we can discuss the background mechanisms of photocurrent generation and photovoltaic energy harvesting.

  1. Building opportunities for photovoltaics in the U.S. Final report [PV BONUS

    SciTech Connect

    Michael Nicklas

    1999-09-08

    The objective of the North Carolina's PV Bonus Team was to develop and demonstrate a commercially viable, building-integrated, photovoltaic system that, in addition to providing electricity, would capture and effectively utilize the thermal energy produced by the photovoltaic array. This project objective was successfully achieved by designing, testing, constructing, and monitoring two roof integrated photovoltaic systems--one on a Applebee's Restaurant in Salisbury, North Carolina and the second on a Central Carolina Bank in Bessemer City, North Carolina. The goal of Innovative Design is to now use these successful demonstrations to facilitate entry of building integrated, pv/thermal systems into the marketplace. The strategy was to develop the two systems that could be utilized in future applications. Both systems were designed and then constructed at the North Carolina Solar Center at North Carolina State University. After extensive testing at the North Carolina Solar Center, the systems were moved to the actual construction sites and implemented. The Applebee's Restaurant system was designed to substitute for the roof assembly of a low sloping, south-facing sunspace roof that typically incorporated clay tile. After monitoring the installed system for one year it was determined that the 1.2 kilowatt (peak) system produces an average peak reduction of 1 kilowatt (rated peak is 1.7 kiloWatts), saves 1,529 kilowatt-hours of electricity, and offsets 11,776 kilowatt-hours of thermal energy savings used to pre-heat water. A DC fan connected directly to eight of the thirty-two amorphous modules moves air through air passages mounted on the backside of the modules and into a closed loop duct system to a heat exchanger. This heat exchanger is, in turn, connected to a pre-heat hot water tank that is used to heat the water for the restaurant. The Central Carolina Bank system was designed to substitute for the roof assembly of the drive-in window area of the bank. The

  2. Wind loads on flat plate photovoltaic array fields. Phase III, final report

    SciTech Connect

    Miller, R.D.; Zimmerman, D.K.

    1981-04-01

    The results of an experimental analysis (boundary layer wind tunnel test) of the aerodynamic forces resulting from winds acting on flat plate photovoltaic arrays are presented. Local pressure coefficient distributions and normal force coefficients on the arrays are shown and compared to theoretical results. Parameters that were varied when determining the aerodynamic forces included tilt angle, array separation, ground clearance, protective wind barriers, and the effect of the wind velocity profile. Recommended design wind forces and pressures are presented, which envelop the test results for winds perpendicular to the array's longitudinal axis. This wind direction produces the maximum wind loads on the arrays except at the array edge where oblique winds produce larger edge pressure loads.

  3. Building-integrated photovoltaics (BIPV): Analysis and US market potential. Final report

    SciTech Connect

    Frantzis, L.; Friedman, D.; Hill, S.; Teagan, P.; Strong, S.; Strong, M.

    1995-02-01

    Arthur D. Little, Inc., in conjunction with Solar Design Associates, conducted a study for the US Department of Energy (DOE), Office of Building Technologies (OBT) to determine the market potential for grid-connected, building-integrated photovoltaics (BIPV). This study defines BIPV as two types of applications: (1) where the PV modules are an integral part of the building, often serving as the exterior weathering skin; and (2) the PV modules are mounted on the existing building exterior. Both of these systems are fully integrated with the energy usage of the building and have potential for significant market penetration in the US. Off-grid building applications also offer a near-term market for BIPV, but are not included in the scope of this study.

  4. See-through dye-sensitized solar cells: photonic reflectors for tandem and building integrated photovoltaics.

    PubMed

    Heiniger, Leo-Philipp; O'Brien, Paul G; Soheilnia, Navid; Yang, Yang; Kherani, Nazir P; Grätzel, Michael; Ozin, Geoffrey A; Tétreault, Nicolas

    2013-10-25

    See-through dye-sensitized solar cells with 1D photonic crystal Bragg reflector photoanodes show an increase in peak external quantum efficiency of 47% while still maintaining high fill factors, resulting in an almost 40% increase in power conversion efficiency. These photoanodes are ideally suited for tandem and building integrated photovoltaics.

  5. Organic photovoltaic cells based on ZnO thin film electrodes.

    PubMed

    Ghica, C; Ion, L; Epurescu, G; Nistor, L; Antohe, S; Dinescu, M

    2010-02-01

    Due to its wide band-gap (ca. 3.4 eV), ZnO is a possible candidate material to be used as transparent electrode for a new class of photovoltaic (PV) cells. Also, an increased interest for the photovoltaic properties of several organic monomers and polymers (merocyanines, phthalocyanines and porphyrins) was noticed, because of their high optical absorption in the visible region of the spectrum allowing them to be used as potential inexpensive materials for solar cells. Preparation and properties of CuPc (copper phthalocyanine) based photovoltaic cells using ZnO thin films as transparent conductor electrodes are presented in this paper. ZnO layers are grown by pulsed laser deposition, while the organic layers are obtained by thermal evaporation. Structural characterization is performed by electron microscopy. Optical and transport properties of the mutilayered structures are obtained by electrical and spectro-photometric measurements. The influence of the ZnO-polymer interface on the external quantum efficiency (EQE) of the photovoltaic cell is clearly evidenced by our measurements.

  6. The effect of branching in a semiconducting polymer on the efficiency of organic photovoltaic cells.

    PubMed

    Heintges, Gaël H L; van Franeker, Jacobus J; Wienk, Martijn M; Janssen, René A J

    2016-01-04

    The impact of branching in a diketopyrrolopyrrole polymer on the performance of polymer-fullerene photovoltaic cells is investigated. Compared to the linear polymer, the branched polymer affords a more finely dispersed fibrillar network in the photoactive layer and as a result a large enhancement of the photocurrent and power conversion efficiency.

  7. Anomalous photovoltaic effect in organic-inorganic hybrid perovskite solar cells.

    PubMed

    Yuan, Yongbo; Li, Tao; Wang, Qi; Xing, Jie; Gruverman, Alexei; Huang, Jinsong

    2017-03-01

    Organic-inorganic hybrid perovskites (OIHPs) have been demonstrated to be highly successful photovoltaic materials yielding very-high-efficiency solar cells. We report the room temperature observation of an anomalous photovoltaic (APV) effect in lateral structure OIHP devices manifested by the device's open-circuit voltage (VOC) that is much larger than the bandgap of OIHPs. The persistent VOC is proportional to the electrode spacing, resembling that of ferroelectric photovoltaic devices. However, the APV effect in OIHP devices is not caused by ferroelectricity. The APV effect can be explained by the formation of tunneling junctions randomly dispersed in the polycrystalline films, which allows the accumulation of photovoltage at a macroscopic level. The formation of internal tunneling junctions as a result of ion migration is visualized with Kelvin probe force microscopy scanning. This observation points out a new avenue for the formation of large and continuously tunable VOC without being limited by the materials' bandgap.

  8. Anomalous photovoltaic effect in organic-inorganic hybrid perovskite solar cells

    PubMed Central

    Yuan, Yongbo; Li, Tao; Wang, Qi; Xing, Jie; Gruverman, Alexei; Huang, Jinsong

    2017-01-01

    Organic-inorganic hybrid perovskites (OIHPs) have been demonstrated to be highly successful photovoltaic materials yielding very-high-efficiency solar cells. We report the room temperature observation of an anomalous photovoltaic (APV) effect in lateral structure OIHP devices manifested by the device’s open-circuit voltage (VOC) that is much larger than the bandgap of OIHPs. The persistent VOC is proportional to the electrode spacing, resembling that of ferroelectric photovoltaic devices. However, the APV effect in OIHP devices is not caused by ferroelectricity. The APV effect can be explained by the formation of tunneling junctions randomly dispersed in the polycrystalline films, which allows the accumulation of photovoltage at a macroscopic level. The formation of internal tunneling junctions as a result of ion migration is visualized with Kelvin probe force microscopy scanning. This observation points out a new avenue for the formation of large and continuously tunable VOC without being limited by the materials’ bandgap. PMID:28345043

  9. The effect of the low Earth orbit environment on space solar cells: Results of the Advanced Photovoltaic Experiment (S0014)

    NASA Technical Reports Server (NTRS)

    Brinker, David J.; Hickey, John R.; Scheiman, David A.

    1993-01-01

    The results of post-flight performance testing of the solar cells flown on the Advanced Photovoltaic Experiment are reported. Comparison of post-flight current-voltage characteristics with similar pre-flight data revealed little or no change in solar cell conversion efficiency, confirming the reliability and endurance of space photovoltaic cells. This finding is in agreement with the lack of significant physical changes in the solar cells despite nearly six years in the low Earth orbit environment.

  10. Photovoltaic characteristics of diffused P/+N bulk GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Borrego, J. M.; Keeney, R. P.; Bhat, I. B.; Bhat, K. N.; Sundaram, L. G.; Ghandhi, S. K.

    1982-01-01

    The photovoltaic characteristics of P(+)N junction solar cells fabricated on bulk GaAs by an open tube diffusion technique are described in this paper.Spectral response measurements were analyzed in detail and compared to a computer simulation in order to determine important material parameters. It is projected that proper optimization of the cell parameters can increase the efficiency of the cells from 12.2 percent to close to 20 percent.

  11. NREL Certifies First All-Quantum-Dot Photovoltaic Cell; Demonstrates Stability, Performance (Fact Sheet)

    SciTech Connect

    Not Available

    2011-02-01

    Researchers at the National Renewable Energy Laboratory (NREL) have certified the first all-quantum-dot photovoltaic cell, which was based on lead sulfide and demonstrated reasonable quantum dot solar cell performance for an initial efficiency measurement along with good stability. The certified open-circuit voltage of the quantum dot cell is greater than that possible from bulk lead sulfide because of quantum confinement.

  12. Thermionic photovoltaic energy converter

    NASA Technical Reports Server (NTRS)

    Chubb, D. L. (Inventor)

    1985-01-01

    A thermionic photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or gallium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

  13. Photovoltaic Engineering

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The Ohio Aerospace Institute through David Scheiman and Phillip Jenkins provided the Photovoltaics Branch at the NASA Glenn Research Center (GRC) with expertise in photovoltaic (PV) research, flight experiments and solar cell calibration. NASA GRC maintains the only world-class solar cell calibration and measurement facility within NASA. GRC also has a leadership role within the solar cell calibration community, and is leading the effort to develop ISO standards for solar cell calibration. OAI scientists working under this grant provided much of the expertise and leadership in this area.

  14. Intermediate reflectors for enhanced top cell performance in photovoltaic thin-film tandem cells.

    PubMed

    Bielawny, Andreas; Rockstuhl, Carsten; Lederer, Falk; Wehrspohn, Ralf B

    2009-05-11

    We have investigated the impact of three types of intermediate reflectors on the absorption enhancement in the top cell of micromorph tandem solar cells using rigorous diffraction theory. As intermediate reflectors we consider homogenous dielectric thin-films and 1D and 3D photonic crystals. Besides the expected absorption enhancements in cases where photonic band gaps are matched to the absorption edge of the semiconductor, our results distinguish between the impact of zero order Bragg-resonances and diffraction-based enhancement at larger lattice constants of the 3D photonic crystal. Our full-spectrum analysis permits for a quantitative prediction of the photovoltaic conversion efficiency increase of the a-Si:H top cell.

  15. Immiscible solvents enabled nanostructure formation for efficient polymer photovoltaic cells.

    PubMed

    Lee, Dong-Hyun; Michael Yang, Yang; You, Jingbi; Richard, Eric; Li, Gang

    2014-07-25

    Organic photovoltaics (OPVs) fabricated via solution processing are an attractive way to realize low cost solar energy harvesting. Bulk heterojunction (BHJ) devices are the most successful design, but their morphology is less controllable. In this manuscript, we describe a simple approach to realize 'ordered' BHJ morphology using two immiscible solvents with different boiling point and a quasi-bilayer approach. Tunable fine structures were demonstrated in poly(3-hexylthiophene) (P3HT) and [6,6]-Phenyl C61 butyric acid methyl ester (PCBM) model systems, and the devices with optimized fine structure showed a 33% efficiency enhancement compared to those with a planar bilayer structure.

  16. Design of solar cells for use in photovoltaic/thermal collectors

    NASA Astrophysics Data System (ADS)

    Cox, C. H., III

    1980-11-01

    A promising design development for combined photovoltaic/thermal (PV/T) collectors is one in which the photovoltaic cell is both the conversion device for electrical energy and the absorber of thermal energy. To accomplish this, the PV cell design is modified to use the approximately 25 percent of the air mass 1 spectrum at lambda greater than 1.1 micrometers that is currently rejected by the cell. The parameters investigated are: cell back metallization, back surface field, texture etching and anti-reflective coating. A model indicating the increase in absorptance as a function of these parameters is presented, together with the results of experimental measurements. Discussion closes with the presentation of a PV/T collector design that incorporates the improved cells, has 10 percent greater thermal output than current PV/T collectors, and exhibits no degradation in electrical output.

  17. Spectral splitting photovoltaics using perovskite and wideband dye-sensitized solar cells.

    PubMed

    Kinoshita, Takumi; Nonomura, Kazuteru; Jeon, Nam Joong; Giordano, Fabrizio; Abate, Antonio; Uchida, Satoshi; Kubo, Takaya; Seok, Sang Il; Nazeeruddin, Mohammad Khaja; Hagfeldt, Anders; Grätzel, Michael; Segawa, Hiroshi

    2015-11-05

    The extension of the light absorption of photovoltaics into the near-infrared region is important to increase the energy conversion efficiency. Although the progress of the lead halide perovskite solar cells is remarkable, and high conversion efficiency of >20% has been reached, their absorption limit on the long-wavelength side is ∼800 nm. To further enhance the conversion efficiency of perovskite-based photovoltaics, a hybridized system with near-infrared photovoltaics is a useful approach. Here we report a panchromatic sensitizer, coded DX3, that exhibits a broad response into the near-infrared, up to ∼1100 nm, and a photocurrent density exceeding 30 mA cm(-2) in simulated air mass 1.5 standard solar radiation. Using the DX3-based dye-sensitized solar cell in conjunction with a perovskite cell that harvests visible light, the hybridized mesoscopic photovoltaics achieved a conversion efficiency of 21.5% using a system of spectral splitting.

  18. Spectral splitting photovoltaics using perovskite and wideband dye-sensitized solar cells

    PubMed Central

    Kinoshita, Takumi; Nonomura, Kazuteru; Joong Jeon, Nam; Giordano, Fabrizio; Abate, Antonio; Uchida, Satoshi; Kubo, Takaya; Seok, Sang Il; Nazeeruddin, Mohammad Khaja; Hagfeldt, Anders; Grätzel, Michael; Segawa, Hiroshi

    2015-01-01

    The extension of the light absorption of photovoltaics into the near-infrared region is important to increase the energy conversion efficiency. Although the progress of the lead halide perovskite solar cells is remarkable, and high conversion efficiency of >20% has been reached, their absorption limit on the long-wavelength side is ∼800 nm. To further enhance the conversion efficiency of perovskite-based photovoltaics, a hybridized system with near-infrared photovoltaics is a useful approach. Here we report a panchromatic sensitizer, coded DX3, that exhibits a broad response into the near-infrared, up to ∼1100 nm, and a photocurrent density exceeding 30 mA cm−2 in simulated air mass 1.5 standard solar radiation. Using the DX3-based dye-sensitized solar cell in conjunction with a perovskite cell that harvests visible light, the hybridized mesoscopic photovoltaics achieved a conversion efficiency of 21.5% using a system of spectral splitting. PMID:26538097

  19. Performance of solar energy converters: Thermal collectors and photovoltaic cells; Lectures of the Course, Ispra, Italy, November 11-18, 1981

    NASA Astrophysics Data System (ADS)

    Beghi, G.

    The operational principles, performance results, and test and equipment designs for photovoltaic and solar flat plate collector systems are explored, with emphasis given to European programs. Attention is given to solar simulator and outdoor tests for collectors, and to indoor test calibration techniques and reliability testing procedure for photovoltaic cells and modules. The design and operation of the solar simulators at Ispra are described, together with the hybrid solar heating system for the facility and apparatus used for simulating corrosive atmospheres for testing collector panels. Simulation models being validated after development on the basis of data from previous test projects are presented, and current solar cell test programs in Europe are detailed. Finally, standardized solar cell and module and collector testing methodologies being implemented to qualify equipment to be tested in projects run by the Commission of the European Communities are reported. For individual items see A83-40521 to A83-40539

  20. Design and optimization of very high power density monochromatic GaAs photovoltaic cells

    SciTech Connect

    Algora, C.; Diaz, V.

    1998-09-01

    This paper deals with the structure optimization of very high power density monochromatic GaAs photovoltaic cells and the theoretical prediction of their performance at irradiances ranging from 0.1 to 100 W/cm{sup 2}. A multifaceted optimum design including the front metal grid, device size and the semiconductor layer structure is presented. The variation in efficiency depending on emitter thickness, base thickness, emitter doping and base doping is also addressed. The objective of this being the configuration of a structure suitable for working up to 100 W/cm{sup 2} without the detrimental influence of series resistance. For this, a detailed analysis of the effect of series resistance and the quantitative determination of its different components is carried out. The optimum wavelength is 830 nm at 300 K for all the analyzed light intensities, in which a 63% peak efficiency under an irradiance of 100 W/cm{sup 2} for a p/n structure is obtained. The temperature effect on device performance in the 273--350 K range is also studied. Finally, the influence of device processing is analyzed.

  1. Fatigue degradation and electric recovery in Silicon solar cells embedded in photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Paggi, Marco; Berardone, Irene; Infuso, Andrea; Corrado, Mauro

    2014-03-01

    Cracking in Silicon solar cells is an important factor for the electrical power-loss of photovoltaic modules. Simple geometrical criteria identifying the amount of inactive cell areas depending on the position of cracks with respect to the main electric conductors have been proposed in the literature to predict worst case scenarios. Here we present an experimental study based on the electroluminescence (EL) technique showing that crack propagation in monocrystalline Silicon cells embedded in photovoltaic (PV) modules is a much more complex phenomenon. In spite of the very brittle nature of Silicon, due to the action of the encapsulating polymer and residual thermo-elastic stresses, cracked regions can recover the electric conductivity during mechanical unloading due to crack closure. During cyclic bending, fatigue degradation is reported. This pinpoints the importance of reducing cyclic stresses caused by vibrations due to transportation and use, in order to limit the effect of cracking in Silicon cells.

  2. Fatigue degradation and electric recovery in Silicon solar cells embedded in photovoltaic modules

    PubMed Central

    Paggi, Marco; Berardone, Irene; Infuso, Andrea; Corrado, Mauro

    2014-01-01

    Cracking in Silicon solar cells is an important factor for the electrical power-loss of photovoltaic modules. Simple geometrical criteria identifying the amount of inactive cell areas depending on the position of cracks with respect to the main electric conductors have been proposed in the literature to predict worst case scenarios. Here we present an experimental study based on the electroluminescence (EL) technique showing that crack propagation in monocrystalline Silicon cells embedded in photovoltaic (PV) modules is a much more complex phenomenon. In spite of the very brittle nature of Silicon, due to the action of the encapsulating polymer and residual thermo-elastic stresses, cracked regions can recover the electric conductivity during mechanical unloading due to crack closure. During cyclic bending, fatigue degradation is reported. This pinpoints the importance of reducing cyclic stresses caused by vibrations due to transportation and use, in order to limit the effect of cracking in Silicon cells. PMID:24675974

  3. Nanoparticle Solar Cell Final Technical Report

    SciTech Connect

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

    2008-06-17

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

  4. Interfacial charge separation and photovoltaic efficiency in Fe(ii)-carbene sensitized solar cells.

    PubMed

    Pastore, Mariachiara; Duchanois, Thibaut; Liu, Li; Monari, Antonio; Assfeld, Xavier; Haacke, Stefan; Gros, Philippe C

    2016-10-12

    The first combined theoretical and photovoltaic characterization of both homoleptic and heteroleptic Fe(ii)-carbene sensitized photoanodes in working dye sensitized solar cells (DSSCs) has been performed. Three new heteroleptic Fe(ii)-NHC dye sensitizers have been synthesized, characterized and tested. Despite an improved interfacial charge separation in comparison to the homoleptic compounds, the heteroleptic complexes did not show boosted photovoltaic performances. The ab initio quantitative analysis of the interfacial electron and hole transfers and the measured photovoltaic data clearly evidenced fast recombination reactions for heteroleptics, even associated with un unfavorable directional electron flow, and hence slower injection rates, in the case of homoleptics. Notably, quantum mechanics calculations revealed that deprotonation of the not anchored carboxylic function in the homoleptic complex can effectively accelerate the electron injection rate and completely suppress the electron recombination to the oxidized dye. This result suggests that introduction of strong electron-donating substituents on the not-anchored carbene ligand in heteroleptic complexes, in such a way of mimicking the electronic effects of the carboxylate functionality, should yield markedly improved interfacial charge generation properties. The present results, providing for the first time a detailed understanding of the interfacial electron transfers and photovoltaic characterization in Fe(ii)-carbene sensitized solar cells, open the way to a rational molecular engineering of efficient iron-based dyes for photoelectrochemical applications.

  5. High temperature solid oxide regenerative fuel cell for solar photovoltaic energy storage

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    1987-01-01

    A hydrogen-oxygen regenerative fuel cell (RFC) energy storage system based on high temperature solid oxide fuel cell (SOFC) technology is described. The reactants are stored as gases in lightweight insulated pressure vessels. The product water is stored as a liquid in saturated equilibrium with the fuel gas. The system functions as a secondary battery and is applicable to darkside energy storage for solar photovoltaics.

  6. A-D-A small molecules for solution-processed organic photovoltaic cells.

    PubMed

    Ni, Wang; Wan, Xiangjian; Li, Miaomiao; Wang, Yunchuang; Chen, Yongsheng

    2015-03-25

    A-D-A small molecules have drawn more and more attention in solution-processed organic solar cells due to the advantages of a diversity of structures, easy control of energy levels, etc. Recently, a power conversion efficiency of nearly 10% has been achieved through careful material design and device optimization. This feature article reviews recent representative progress in the design and application of A-D-A small molecules in organic photovoltaic cells.

  7. Self-assembled plasmonic electrodes for high-performance organic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Luhman, Wade A.; Hoon Lee, Si; Johnson, Timothy W.; Holmes, Russell J.; Oh, Sang-Hyun

    2011-09-01

    We investigate thin Ag films incorporating plasmonic nanohole arrays as transparent conducting electrodes for organic photovoltaic cells. Plasmonic electrodes are fabricated using nanosphere lithography to create hexagonal nanohole arrays over centimeter-sized areas. Devices constructed using a nanopatterned Ag anode show power conversion efficiencies that exceed those of devices constructed on conventional indium-tin-oxide, independent of light polarization. In comparison to cells constructed on unpatterned Ag, the power conversion efficiency is noted to double with patterning.

  8. Electroanalytical Evaluation of Lithium Ion Batteries and Photovoltaic Cells

    NASA Astrophysics Data System (ADS)

    Crain, Daniel Jacob

    Efficient solar energy conversion and electrical energy storage have been studied widely for decades. However, as materials development and process engineering for these devices have advanced through the years, some of the traditional characterization techniques have gradually fallen short of providing quantitative information that is necessary for further significant advancements in these fields. In this work a modern electroanalytical framework for characterization of silicon solar cells and lithium ion batteries is presented. Electroanalytical characterization of lithium ion battery electrodes is achieved through a strategic combination of the D.C. techniques of slow scan cyclic voltammetry, galvanostatic charge/discharge, Ragone Analysis with the A.C. technique of impedance spectroscopy (IS) coupled with complex nonlinear least squares (CNLS) analysis of impedance spectra. Primarily this investigation focuses on characterization of intercalating composite electrodes where the active material is either lithium manganese oxide (cathode,LiMn2O4) or lithium titanate (anode, Li4Ti5O12). Aspects of high power limitations are studied in detail to elucidate physical parameters that control electrode performance under rapid charge/discharge conditions. Electroanalytical evaluation of the p-n junction silicon solar cell with a back surface field (BSF) is accomplished through the use of linear sweep voltammetry (LSV) and IS combined with CNLS analysis. Although LSV has been previously used for characterization of silicon solar cells the use of impedance techniques is relatively new. Temperature and voltage dependence of the series resistance (Rs), diode quality factor (m), minority carrier lifetime and BSF electrical parameters obtained through IS are examined. The temperature dependence of results obtained from LSV such as the open circuit potential (Voc), short circuit current (Jsc), fill factor (FF) and conversion efficiency are also explored. Finally, a parative

  9. Turbulence convective heat transfer for cooling the photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Arianmehr, Iman

    Solar PV (photovoltaic) is a rapidly advancing renewable energy technology which converts sunlight directly into electricity. One of the outstanding challenges of the current PV technology is the reduction in its conversion efficiency with increasing PV panel temperature, which is closely associated with the increase in solar intensity and the ambient temperature surrounding the PV panels. To more effectively capture the available energy when the sun is most intense, significant efforts have been invested in active and passive cooling research over the last few years. While integrated cooling systems can lead to the highest total efficiencies, they are usually neither the most feasible nor the most cost effective solutions. This work examines some simple passive means of manipulating the prevailing wind turbulence to enhance convective heat transfer over a heated plate in a wind tunnel.

  10. Photovoltaic concentrators

    NASA Astrophysics Data System (ADS)

    Boes, E. C.

    1980-01-01

    A status report on photovoltaic (PV) concentrators technology is presented. The major topics covered are as follows: (1) current PV concentrator arrays; designs, performances, and costs; (2) current PV concentrator array components; cells and cell assemblies, optical concentrators, support structures, tracking, and drive; (3) design of PV concentrator arrays; and (4) array manufacturing technology.

  11. Liquid Crystals for Organic Photovoltaics

    NASA Astrophysics Data System (ADS)

    O'Neill, Mary; Kelly, Stephen M.

    As discussed in Chaps. 2 (10.1007/978-90-481-2873-0_2), 3 (10.1007/978-90-481-2873-3), 5 (10.1007/978-90-481-2873-5) and 6 (10.1007/978-90-481-2873-6), columnar, smectic and, more recently, nematic liquid crystals are widely recognized as very promising charge-transporting organic semiconductors due to their ability to spontaneously self-assemble into highly ordered domains in uniform thin films over large areas. This and their broad absorption spectra make them suitable as active materials for organic photovoltaic devices. In this chapter, we discuss the use of liquid crystals in such devices. Firstly, we examine the principle of power generation via the photovoltaic effect in organic materials and the various device configurations that can optimise efficiency. Then we discuss photovoltaic devices incorporating columnar liquid crystals combined with electron accepting materials based on either perylene or fullerene. The use of nematic and sanditic liquid crystals in photovoltaics is investigated as well as a novel solar cell concentrator incorporating liquid crystals. Finally, we analyse the benefits and limitations of liquid-crystal-based photovoltaics in the context of the state-of-the-art for organics photovoltaics.

  12. Comparison of photovoltaic cell temperatures in modules operating with exposed and enclosed back surfaces

    NASA Technical Reports Server (NTRS)

    Namkoong, D.; Simon, F. F.

    1981-01-01

    Four different photovoltaic module designs were tested to determine the cell temperature of each design. The cell temperatures were compared to those obtained on identical design, using the same nominal operating cell temperature (NOCT) concept. The results showed that the NOCT procedure does not apply to the enclosed configurations due to continuous transient conditions. The enclosed modules had higher cell temperatures than the open modules, and insulated modules higher than the uninsulated. The severest performance loss - when translated from cell temperatures - 17.5 % for one enclosed, insulated module as a compared to that module mounted openly.

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

    PubMed

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

    2015-02-18

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  15. Tandem-structured, hot electron based photovoltaic cell with double Schottky barriers.

    PubMed

    Lee, Young Keun; Lee, Hyosun; Park, Jeong Young

    2014-04-03

    We demonstrate a tandem-structured, hot electron based photovoltaic cell with double Schottky barriers. The tandem-structured, hot electron based photovoltaic cell is composed of two metal/semiconductor interfaces. Two types of tandem cells were fabricated using TiO2/Au/Si and TiO2/Au/TiO2, and photocurrent enhancement was detected. The double Schottky barriers lead to an additional pathway for harvesting hot electrons, which is enhanced through multiple reflections between the two barriers with different energy ranges. In addition, light absorption is improved by the band-to-band excitation of both semiconductors with different band gaps. Short-circuit current and energy conversion efficiency of the tandem-structured TiO2/Au/Si increased by 86% and 70%, respectively, compared with Au/Si metal/semiconductor nanodiodes, showing an overall solar energy conversion efficiency of 5.3%.

  16. Tandem-structured, hot electron based photovoltaic cell with double Schottky barriers

    PubMed Central

    Lee, Young Keun; Lee, Hyosun; Park, Jeong Young

    2014-01-01

    We demonstrate a tandem-structured, hot electron based photovoltaic cell with double Schottky barriers. The tandem-structured, hot electron based photovoltaic cell is composed of two metal/semiconductor interfaces. Two types of tandem cells were fabricated using TiO2/Au/Si and TiO2/Au/TiO2, and photocurrent enhancement was detected. The double Schottky barriers lead to an additional pathway for harvesting hot electrons, which is enhanced through multiple reflections between the two barriers with different energy ranges. In addition, light absorption is improved by the band-to-band excitation of both semiconductors with different band gaps. Short-circuit current and energy conversion efficiency of the tandem-structured TiO2/Au/Si increased by 86% and 70%, respectively, compared with Au/Si metal/semiconductor nanodiodes, showing an overall solar energy conversion efficiency of 5.3%. PMID:24694838

  17. Solar cell array design handbook - The principles and technology of photovoltaic energy conversion

    NASA Technical Reports Server (NTRS)

    Rauschenbach, H. S.

    1980-01-01

    Photovoltaic solar cell array design and technology for ground-based and space applications are discussed from the user's point of view. Solar array systems are described, with attention given to array concepts, historical development, applications and performance, and the analysis of array characteristics, circuits, components, performance and reliability is examined. Aspects of solar cell array design considered include the design process, photovoltaic system and detailed array design, and the design of array thermal, radiation shielding and electromagnetic components. Attention is then given to the characteristics and design of the separate components of solar arrays, including the solar cells, optical elements and mechanical elements, and the fabrication, testing, environmental conditions and effects and material properties of arrays and their components are discussed.

  18. Thin film heterojunction photovoltaic cells and methods of making the same

    SciTech Connect

    Basol, Bulent M.; Tseng, Eric S.; Rod, Robert L.

    1983-06-14

    A method of fabricating a thin film heterojunction photovoltaic cell which comprises depositing a film of a near intrinsic or n-type semiconductor compound formed of at least one of the metal elements of Class II B of the Periodic Table of Elements and at least tellurium and then heating said film at a temperature between about 250.degree. C. and 500.degree. C. for a time sufficient to convert said film to a suitably low resistivity p-type semiconductor compound. Such film may be deposited initially on the surface of an n-type semiconductor substrate. Alternatively, there may be deposited on the converted film a layer of n-type semiconductor compound different from the film semiconductor compound. The resulting photovoltaic cell exhibits a substantially increased power output over similar cells not subjected to the method of the present invention.

  19. Thin film heterojunction photovoltaic cells and methods of making the same

    SciTech Connect

    Basol, B.M.; Rod, R.L.; Tseng, E.S.

    1983-06-14

    A method of fabricating a thin film heterojunction photovoltaic cell which comprises depositing a film of a near intrinsic or n-type semiconductor compound formed of at least one of the metal elements of class II B of the periodic table of elements and at least tellurium and then heating said film at a temperature between about 250/sup 0/ C. And 500/sup 0/ C. For a time sufficient to convert said film to a suitably low resistivity p-type semiconductor compound. Such film may be deposited initially on the surface of an n-type semiconductor substrate. Alternatively, there may be deposited on the converted film a layer of n-type semiconductor compound different from the film semiconductor compound. The resulting photovoltaic cell exhibits a substantially increased power output over similar cells not subjected to the method of the present invention.

  20. Flexible concentrator photovoltaics based on microscale silicon solar cells embedded in luminescent waveguides.

    PubMed

    Yoon, Jongseung; Li, Lanfang; Semichaevsky, Andrey V; Ryu, Jae Ha; Johnson, Harley T; Nuzzo, Ralph G; Rogers, John A

    2011-06-14

    Unconventional methods to exploit monocrystalline silicon and other established materials in photovoltaic (PV) systems can create new engineering opportunities, device capabilities and cost structures. Here we show a type of composite luminescent concentrator PV system that embeds large scale, interconnected arrays of microscale silicon solar cells in thin matrix layers doped with luminophores. Photons that strike cells directly generate power in the usual manner; those incident on the matrix launch wavelength-downconverted photons that reflect and waveguide into the sides and bottom surfaces of the cells to increase further their power output, by more than 300% in examples reported here. Unlike conventional luminescent photovoltaics, this unusual design can be implemented in ultrathin, mechanically bendable formats. Detailed studies of design considerations and fabrication aspects for such devices, using both experimental and computational approaches, provide quantitative descriptions of the underlying materials science and optics.

  1. Si concentrator solar cell development. [Final report

    SciTech Connect

    Krut, D.D.

    1994-10-01

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

  2. Evaluation of photovoltaic power generation system using spherical silicon solar cells and SiC-FET inverter

    NASA Astrophysics Data System (ADS)

    Matsumoto, Taisuke; Oku, Takeo; Hiramatsu, Koichi; Yasuda, Masashi; Shirahata, Yasuhiro; Shimono, Akio; Takeda, Yoshikazu; Murozono, Mikio

    2016-02-01

    A photovoltaic power generation system using spherical silicon (Si) solar cells and silicon carbide (SiC) field effect transistor (FET) inverter for photovoltaic applications was constructed and evaluated. The spherical Si solar cells were connected to the SiC-FET inverter and were used as a power source. Comparing the photovoltaic power generation system using an ordinary Si-FET inverter, direct current-alternating current conversion efficiencies of the SiC-FET inverter were improved due to reduction of power loss in the SiC-FET inverter.

  3. The electrodeposition of multilayers on a polymeric substrate in flexible organic photovoltaic solar cells

    NASA Astrophysics Data System (ADS)

    Guedes, Andre F. S.; Guedes, Vilmar P.; Souza, Monica L.; Tartari, Simone; Cunha, Idaulo J.

    2015-09-01

    Flexible organic photovoltaic solar cells have drawn intense attention due to their advantages over competing solar cell technologies. The method utilized to deposit as well as to integrate solutions and processed materials, manufacturing organic solar cells by the Electrodeposition System, has been presented in this research. In addition, we have demonstrated a successful integration of a process for manufacturing the flexible organic solar cell prototype and we have discussed on the factors that make this process possible. The maximum process temperature was 120°C, which corresponds to the baking of the active polymeric layer. Moreover, the new process of the Electrodeposition of complementary active layer is based on the application of voltage versus time in order to obtain a homogeneous layer with thin film. This thin film was not only obtained by the electrodeposition of PANI-X1 on P3HT/PCBM Blend, but also prepared in perchloric acid solution. Furthermore, these flexible organic photovoltaic solar cells presented power conversion efficiency of 12% and the inclusion of the PANI-X1 layer reduced the effects of degradation on these organic photovoltaic panels induced by solar irradiation. Thus, in the Scanning Electron Microscopy (SEM), these studies have revealed that the surface of PANI-X1 layers is strongly conditioned by the dielectric surface morphology.

  4. Fabrication of ordered bulk heterojunction organic photovoltaic cells using nanopatterning and electrohydrodynamic spray deposition methods.

    PubMed

    Park, Sung-Eun; Kim, Sehwan; Kim, Kangmin; Joe, Hang-Eun; Jung, Buyoung; Kim, Eunkyoung; Kim, Woochul; Min, Byung-Kwon; Hwang, Jungho

    2012-12-21

    Organic photovoltaic cells with an ordered heterojunction (OHJ) active layer are expected to show increased performance. In the study described here, OHJ cells were fabricated using a combination of nanoimprinting and electrohydrodynamic (EHD) spray deposition methods. After an electron donor material was nanoimprinted with a PDMS stamp (valley width: 230 nm, period: 590 nm) duplicated from a Si nanomold, an electron acceptor material was deposited onto the nanoimprinted donor layer using an EHD spray deposition method. The donor-acceptor interface layer was observed by obtaining cross-sectional images with a focused ion beam (FIB) microscope. The photocurrent generation performance of the OHJ cells was evaluated with the current density-voltage curve under air mass (AM) 1.5 conditions. It was found that the surface morphology of the electron acceptor layer affected the current and voltage outputs of the photovoltaic cells. When an electron acceptor layer with a smooth thin (250 nm above the valley of the electron donor layer) surface morphology was obtained, power conversion efficiency was as high as 0.55%. The electrohydrodynamic spray deposition method used to produce OHJ photovoltaic cells provides a means for the adoption of large area, high throughput processes.

  5. Mo1-xWxSe2-Based Schottky Junction Photovoltaic Cells.

    PubMed

    Yi, Sum-Gyun; Kim, Sung Hyun; Park, Sungjin; Oh, Donggun; Choi, Hwan Young; Lee, Nara; Choi, Young Jai; Yoo, Kyung-Hwa

    2016-12-14

    We developed Schottky junction photovoltaic cells based on multilayer Mo1-xWxSe2 with x = 0, 0.5, and 1. To generate built-in potentials, Pd and Al were used as the source and drain electrodes in a lateral structure, and Pd and graphene were used as the bottom and top electrodes in a vertical structure. These devices exhibited gate-tunable diode-like current rectification and photovoltaic responses. Mo0.5W0.5Se2 Schottky diodes with Pd and Al electrodes exhibited higher photovoltaic efficiency than MoSe2 and WSe2 devices with Pd and Al electrodes, likely because of the greater adjusted band alignment in Mo0.5W0.5Se2 devices. Furthermore, we showed that Mo0.5W0.5Se2-based vertical Schottky diodes yield a power conversion efficiency of ∼16% under 532 nm light and ∼13% under a standard air mass 1.5 spectrum, demonstrating their remarkable potential for photovoltaic applications.

  6. Plasmonic Photovoltaic Cells with Dual-Functional Gold, Silver, and Copper Half-Shell Arrays.

    PubMed

    Wu, Ling; Kim, Gyu Min; Nishi, Hiroyasu; Tatsuma, Tetsu

    2017-09-12

    Solid-state photovoltaic cells based on plasmon-induced charge separation (PICS) have attracted growing attention during the past decade. However, the power conversion efficiency (PCE) of the previously reported devices, which are generally loaded with dispersed metal nanoparticles as light absorbers, has not been sufficiently high. Here we report simpler plasmonic photovoltaic cells with interconnected Au, Ag, and Cu half-shell arrays deposited on SiO2@TiO2 colloidal crystals, which serve both as a plasmonic light absorber and as a current collector. The well-controlled and easily prepared plasmonic structure allows precise comparison of the PICS efficiency between different plasmonic metal species. The cell with the Ag half-shell array has higher photovoltaic performance than the cells with Au and Cu half-shell arrays because of the high population of photogenerated energetic electrons, which gives a high electron injection efficiency and suppressed charge recombination probability, achieving the highest PCE among the solid-state PICS devices even without a hole transport layer.

  7. The high intensity solar cell: Key to low cost photovoltaic power

    NASA Technical Reports Server (NTRS)

    Sater, B. L.; Goradia, C.

    1975-01-01

    The design considerations and performance characteristics of the 'high intensity' (HI) solar cell are presented. A high intensity solar system was analyzed to determine its cost effectiveness and to assess the benefits of further improving HI cell efficiency. It is shown that residential sized systems can be produced at less than $1000/kW peak electric power. Due to their superior high intensity performance characteristics compared to the conventional and VMJ cells, HI cells and light concentrators may be the key to low cost photovoltaic power.

  8. DPAL: A New Class of Lasers for CW Power Beaming at Ideal Photovoltaic Cell Wavelengths

    SciTech Connect

    Krupke, W F; Beach, R J; Payne, S A; Kanz, V K; Early, J T

    2003-09-15

    The new class of diode pumped alkali vapor lasers (DPALs) offers high efficiency cw laser beams at wavelengths which efficiently couple to photovoltaic (PV) cells: silicon cells at 895 nm (cesium), and GaAs cells at 795 nm (rubidium) and at 770 nm (potassium). DPAL electrical efficiencies of 25-30% are projected, enabling PV cell efficiencies {approx}40% (Si) and {approx}60% (GaAs). Near-diffraction-limited DPAL device power scaling into the multi-kilowatt regime from a single aperture is projected.

  9. Organic Photovoltaic Cells: Engineering of the Interfaces Electrodes/Organic Material

    NASA Astrophysics Data System (ADS)

    Bernède, J. C.

    2011-10-01

    The power conversion efficiency (PCE) of organic photovoltaic cells (OPV) depends of the efficiency of four steps, exciton generation by light absorption, exciton diffusion to an electron donor/electron acceptor (ED/EA) interface, charge separation giving free holes and electrons and finally, carrier transport and collection. Therefore, in OPV, besides good photoactive materials, the properties of the interfaces between the organic layers and the electrodes are crucial for achieving high carrier collection efficiency and high PCE. Optoelectronic devices require at least one transparent electrode, usually a transparent conductive oxide (TCO). Electrode contacts play a critical role in determining the device efficiencies. Rates of charge collection at the electrodes must be fast and selective. Contact selectivity is often achieved using buffer interlayers interposed between the electrodes and the organic materials. Efficiency of OPV cells, based on organic donor/acceptor heterojunctions can be strongly improved when the transparent conductive anode, is covered by an anode buffer layer (ABL). Currently, indium-tin oxide (ITO) is the most widely used transparent electrode for organic optoelectronic. Here, the effects of different ABLs (0.5 nm of Au, 3 to 4 nm of MoO3 or CuI) onto the ITO anode are studied using electron donors with different HOMO and LUMO levels. The results indicate that a good matching between the work function, of the anode and the HOMO of the organic electron donor, and the value of the anode surface energy, are important factors for an efficient hole transfer. General rules on the ABL efficiency can be deduced from this study.

  10. Polymer substrates for flexible photovoltaic cells application in personal electronic system

    NASA Astrophysics Data System (ADS)

    Znajdek, K.; Sibiński, M.; Strąkowska, A.; Lisik, Z.

    2016-01-01

    The article presents an overview of polymeric materials for flexible substrates in photovoltaic (PV) structures that could be used as power supply in the personal electronic systems. Four types of polymers have been elected for testing. The first two are the most specialized and heat resistant polyimide films. The third material is transparent polyethylene terephthalate film from the group of polyesters which was proposed as a cheap and commercially available substrate for the technology of photovoltaic cells in a superstrate configuration. The last selected polymeric material is a polysiloxane, which meets the criteria of high elasticity, is temperature resistant and it is also characterized by relatively high transparency in the visible light range. For the most promising of these materials additional studies were performed in order to select those of them which represent the best optical, mechanical and temperature parameters according to their usage for flexible substrates in solar cells.

  11. CdSe nanorods dominate photocurrent of hybrid CdSe-P3HT photovoltaic cell.

    PubMed

    Schierhorn, Martin; Boettcher, Shannon W; Peet, Jeffrey H; Matioli, Elison; Bazan, Guillermo C; Stucky, Galen D; Moskovits, Martin

    2010-10-26

    Photovoltaic devices based on organic semiconductors require charge-separating networks (bulk heterojunctions) for optimal performance. Here we report on the fabrication of organic-inorganic photovoltaic devices with tailored (n-type) CdSe nanorod arrays aligned perpendicularly to the substrate. The nanorod lengths varied from 58 ± 12 to 721 ± 15 nm, while the diameters and inter-rod spacings were kept constant at 89.5 ± 7.5 and 41.3 ± 9.9 nm, respectively. Short-circuit densities improved linearly with nanorod length, resulting in power conversion efficiencies of up to 1.38% for cells with nanorods 612 ± 46 nm long. Notably, the cell's efficiency was dominated by exciton generation in the CdSe nanorods.

  12. Synthesis of phthalocyanine derivatives as materials for organic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Collazo-Ramos, Aura

    Organic photovoltaics (OPVs) are used to convert sunlight into electricity by using thin films of organic semiconductors. OPVs have the potential to produce low cost, lightweight, flexible devices with an eased manufacturing process. This technology contains the potential to increase the use of clean, sustainable solar energy, helping manage the global energy and environmental crisis that results majorly from the constant use of fossil fuels as an energy source. The ability to modulate the physical properties of organic molecules by tuning their chemical structure is an advantage for OPVs. Phthalocyanines (Pcs) are highly pi-conjugated synthetic porphyrin analogs that have been explored as active layer components in OPVs due to their high extinction coefficients and hole mobilities. The Pc structure can be modified by the introduction of metals in the core and the incorporation of substituents into the periphery. These modifications tend to tune the solubility, photophysical properties and condensed phase organization of Pcs. The research work in this dissertation describes improved methods towards substituted Pc derivatives addressing: (1) the use of mass spectrometry techniques for Pcs characterization, (2) efforts to achieve materials with near-infrared (NIR) absorption, and (3) the potential of Pc as electron-acceptor materials. Herein, the synthesis of a series of asymmetric and symmetric metallated Pcs has been established, which resulted in interesting chemical, photophysical and electrochemical properties. The materials investigated in this thesis increase the potential of Pcs as organic semiconductors for OPVs.

  13. Highly Efficient Organic Photovoltaic Cells from Polymer-Aligned Carbon Nanotube Dispersed Heterojunctions

    DTIC Science & Technology

    2009-09-01

    turning over the Scotch-supported ACNT film upside down (middle right of Figure 5a), and pushing up the Scotch tape underneath the metal-patterned...nanotube arrays opened up avenues for multifunctional applications, including polymer-aligned carbon nanotube photovoltaic cells. a) Selective...It was thus found that the open-circuit voltage (Voc) increased ( up to 0.93 V) with the decrease in the content of thiophene unit. Although the

  14. Scalable High-Efficiency Thin Crystalline Silicon Photovoltaic Cells Enabled by Light-Trapping Nanostructures

    SciTech Connect

    Chen, Gang; Branham, Matthew S.; Hsu, Wei-Chun; Yerci, Selcuk

    2014-09-02

    This report summarizes the research activities of the Chen group at MIT over the last two years pertaining to our research effort developing and proving light-trapping designs for ultrathin crystalline silicon solar cells. We present a new world record efficiency for a sub-20-micron crystalline silicon device, as well as details on the combined photonic/electronic transport simulation we developed for photovoltaic applications.

  15. A plasmonic liquid junction photovoltaic cell with greatly improved power conversion efficiency.

    PubMed

    Lee, Woo-Ram; Navarrete, Jose; Evanko, Brian; Stucky, Galen D; Mubeen, Syed; Moskovits, Martin

    2016-11-10

    A plasmonic liquid junction photovoltaic cell with greatly improved power conversion efficiency is described. When illuminated with simulated sunlight, the device (Au-TiO2/V(3+)(0.018 M), V(2+)(0.182 M)/Pt) reproducibly and sustainably produces an VOC of 0.50 V and a JSC of 0.5 mA cm(-2), corresponding to a power conversion efficiency of 0.095%.

  16. Molecular Engineering Combined with Cosensitization Leads to Record Photovoltaic Efficiency for Non-ruthenium Solar Cells.

    PubMed

    Hill, Jonathan P

    2016-02-24

    Here comes the sun: By using a combined strategy of molecular engineering and cosensitization, impressively high Jsc and Voc values were achieved for porphyrin dyes, resulting in high photovoltaic efficiencies up to 11.5 %, a record for non-ruthenium dye-sensitized solar cells (DSSCs) with the I(-) /I3 (-) electrolyte. The results provide insight into furthering the development of efficient DSSCs through synergistically enhanced photovoltage and photocurrent.

  17. Evaluation of critical materials in five additional advance design photovoltaic cells

    SciTech Connect

    Smith, S.A.; Watts, R.L.; Martin, P.; Gurwell, W.E.

    1981-02-01

    The objective of this study is to identify potential material supply constraints due to the large-scale deployment of five advanced photovoltaic (PV) cell designs, and to suggest strategies to reduce the impacts of these production capacity limitations and potential future material shortages. The Critical Materials Assessment Program (CMAP) screens the designs and their supply chains and identifies potential shortages which might preclude large-scale use of the technologies. The results of the screening of five advanced PV cell designs are presented: (1) indium phosphide/cadmium sulfide, (2) zinc phosphide, (3) cadmium telluride/cadmium sulfide, (4) copper indium selenium, and (5) cadmium selenide photoelectrochemical. Each of these five cells is screened individually assuming that they first come online in 1991, and that 25 Gwe of peak capacity is online by the year 2000. A second computer screening assumes that each cell first comes online in 1991 and that each cell has a 5 GWe of peak capacity by the year 2000, so that the total online capacity for the five cells is 25 GWe. Based on a review of the preliminary baseline screening results, suggestions were made for varying such parameters as the layer thickness, cell production processes, etc. The resulting PV cell characterizations were then screened again by the CMAP computer code. The CMAP methodology used to identify critical materials is described; and detailed characterizations of the advanced photovoltaic cell designs under investigation, descriptions of additional cell production processes, and the results are presented. (WHK)

  18. Photovoltaic systems based on spectrally selective holographic concentrators. Final report, May-Dec 91

    SciTech Connect

    Ludman, J.E.

    1991-11-01

    The purpose of the work was to demonstrate the feasibility of a new holographic technique for concentrating solar energy and splitting its spectrum with a single hologram to generate power, using two or more solar cells optimized at different portion of the solar spectrum. Various holographic materials, techniques for making holograms, and combinations of solar cells of different materials were investigated. Techniques were developed for testing system efficiencies. A number of potential problems and difficulties were successfully addressed. Holograms and solar cell systems were fabricated and tested, and demonstration units fabricated.

  19. Toxicology of tetramethyltin and other organometals used in photovoltaic cell manufacture

    NASA Astrophysics Data System (ADS)

    Hamilton, L. D.; Medeiros, W. H.; Moskowitz, P. D.; Rybicka, K.

    1988-07-01

    In photovoltaic cell fabrication, organometals (alkyl metals) may be used in such processes as metalorganic chemical vapor deposition, transparent contact oxide deposition, doping, and ion implantation. Although these compounds offer potential performance advantages over earth metals and possibly greater safety in handling than metal hydrides, they are not without risk to health and property. Most organometals can ignite spontaneously in air. Some also react violently with water. Oxidation by-products from these reactions are hazardous to health. Of the organometals used in photovoltaic cell fabrication, only the toxicology of organotins (triethyl-, trimethyl- and tetramethyltin) was studied extensively. In mammalian systems, tetramethyltin is rapidly dealkylated to trimethyltin. Although tin was classified by some investigators as an essential trace element, the effects of organotin compounds on humans are poorly known. Animal studies show that the most prominent effects of trimethyltin are on the central nervous system. Several observations of poisoning were reported; effects ranged from reversible neurologic disorders to death. Limited available data suggest that humans respond to single acute doses and more alarmingly to repeated sub-toxic doses, suggesting a cumulative effect. Toxicologic properties of diethyltelluride also were evaluated in animal experiments. The compound had toxic effects on the blood, liver, kidney, heart, and skin. Based on these studies and others of related compounds (e.g., methylmercury, tributyltin) extreme caution should be exercised in using organometal compounds in photovoltaic cell manufacturing.

  20. Life Cycle Assessment Projection of Photovoltaic Cells: A Case Study on Energy Demand of Quantum Wire Based Photovoltaic Technology Research

    NASA Astrophysics Data System (ADS)

    Mukherjee, Shilpi

    With increasing clean-energy demand, photovoltaic (PV) technologies have gained attention as potential long-term alternative to fossil fuel energy. However, PV research and manufacture still utilize fossil fuel-powered grid electricity. With continuous enhancement of solar conversion efficiency, it is imperative to assess whether overall life cycle efficiency is also being enhanced. Many new-material PV technologies are still in their research phase, and life cycle analyses of these technologies have not yet been performed. For best results, grid dependency must be minimized for PV research, and this can be accomplished by an analytical instrument called Life Cycle Assessment (LCA). LCA is the study of environmental impacts of a product throughout its life cycle. While there are some non-recoverable costs of research, energy is precious, and the PV research community should be aware of its energy consumption. LCA can help identify options for energy conservation through process optimization. A case study was conducted on the energy demand of a test-bed emerging PV technology using life cycle assessment methodology. The test-bed system chosen for this study was a new-material PV cell. The objective was to quantify the total energy demand for the research phase of the test-bed solar cell's life cycle. The objective was accomplished by collecting primary data on energy consumption for each process in the development of this solar cell. It was found that 937 kWh of energy was consumed for performing research on a single sample of the solar cell. For comparison, this energy consumption is 83% of Arkansas's average monthly residential electricity consumption. Life cycle inventory analysis showed that heating, ventilation, and air conditioning consumed the bulk of the energy of research. It is to be noted that the processes studied as part of the solar cell test-bed system are representative of a research process only. Life cycle thinking can identify energy hot-spots and

  1. Potential toxicity of improperly discarded exhausted photovoltaic cells.

    PubMed

    Motta, C M; Cerciello, R; De Bonis, S; Mazzella, V; Cirino, P; Panzuto, R; Ciaravolo, M; Simoniello, P; Toscanesi, M; Trifuoggi, M; Avallone, B

    2016-09-01

    Low tech photovoltaic panels (PVPs) installed in the early '80s are now coming to the end of their life cycle and this raises the problem of their proper disposal. As panels contain potentially toxic elements, unconventional, complex and costly procedures are required to avoid environmental health risks and in countries where environmental awareness and economic resources are limited this may be especially problematic. This work was designed to investigate potential risks from improper disposal of these panels. To accomplish this aim an exhausted panel was broken into pieces and these were placed in water for 30 days. The resulting leached solution was analyzed to determine chemical release or used in toto, to determine its potential toxicity in established tests. The end points were seed germination (on Cucumis sativus and Lens culinaris) and effects on early development in three larval models: two crustaceans, Daphnia magna and Artemia salina, and the sea urchin Paracentrotus lividus. Our results show that the panels release small amounts of electrolytes (Na, Ca and Mg) into solution, along with antimony and manganese, with a concentration under the accepted maximum contaminant level, and nickel at a potentially toxic concentration. Developmental defects are seen in the plant and animal test organisms after experimental exposure to the whole solution leached from the broken panel. The toxic effects revealed in in vitro tests are sufficient to attract attention considering that they are exerted on both plants and aquatic animals and that the number of old PVPs in disposal sites will be very high. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. 10.5% efficient polymer and amorphous silicon hybrid tandem photovoltaic cell

    NASA Astrophysics Data System (ADS)

    Kim, Jeehwan; Hong, Ziruo; Li, Gang; Song, Tze-Bin; Chey, Jay; Lee, Yun Seog; You, Jingbi; Chen, Chun-Chao; Sadana, Devendra K.; Yang, Yang

    2015-03-01

    Thin-film solar cells made with amorphous silicon (a-Si:H) or organic semiconductors are considered as promising renewable energy sources due to their low manufacturing cost and light weight. However, the efficiency of single-junction a-Si:H or organic solar cells is typically <10%, insufficient for achieving grid parity. Here we demonstrate an efficient double-junction photovoltaic cell by employing an a-Si:H film as a front sub-cell and a low band gap polymer:fullerene blend film as a back cell on planar glass substrates. Monolithic integration of 6.0% efficienct a-Si:H and 7.5% efficient polymer:fullerene blend solar cells results in a power conversion efficiency of 10.5%. Such high-efficiency thin-film tandem cells can be achieved by optical management and interface engineering of fully optimized high-performance front and back cells without sacrificing photovoltaic performance in both cells.

  3. 10.5% efficient polymer and amorphous silicon hybrid tandem photovoltaic cell.

    PubMed

    Kim, Jeehwan; Hong, Ziruo; Li, Gang; Song, Tze-bin; Chey, Jay; Lee, Yun Seog; You, Jingbi; Chen, Chun-Chao; Sadana, Devendra K; Yang, Yang

    2015-03-04

    Thin-film solar cells made with amorphous silicon (a-Si:H) or organic semiconductors are considered as promising renewable energy sources due to their low manufacturing cost and light weight. However, the efficiency of single-junction a-Si:H or organic solar cells is typically <10%, insufficient for achieving grid parity. Here we demonstrate an efficient double-junction photovoltaic cell by employing an a-Si:H film as a front sub-cell and a low band gap polymer:fullerene blend film as a back cell on planar glass substrates. Monolithic integration of 6.0% efficienct a-Si:H and 7.5% efficient polymer:fullerene blend solar cells results in a power conversion efficiency of 10.5%. Such high-efficiency thin-film tandem cells can be achieved by optical management and interface engineering of fully optimized high-performance front and back cells without sacrificing photovoltaic performance in both cells.

  4. System design of a photovoltaic flat-panel applications experiment at Busch Gardens, Tampa, Florida. Final report

    SciTech Connect

    Not Available

    1980-03-01

    The detailed system design for a photovoltaic roof shingle module installation at Busch Gardens, Tampa, FL, (also known as the Dark Continent) is discussed. This installation of 4312 shingle solar cell modules of a second-generation design, which was developed under this contract, produces 29.5 kW of peak output at 237 Vdc under Standard Operating Conditions (SOC) with an NOCT at 61/sup 0/C. With a total gross roof area of 330.7 m/sup 2/, this installation yields an areal specific power output of 89.2 watt/m/sup 2/ at SOC. The system which uses an improved, low loss direct-coupled, line-commutated inverter controlled to operate the solar array maximum power operating point, delivers 208Y/120 volt, 3 phase ac in parallel with the Busch Gardens distribution network. The calculated annual ac energy m/sup 2/. The resulting overall system conversion efficiency of 9.2% is considered high for a system using large area circular solar cells.

  5. Light-splitting photovoltaic system utilizing two dual-junction solar cells

    SciTech Connect

    Xiong, Kanglin; Yang, Hui; Lu, Shulong; Dong, Jianrong; Zhou, Taofei; Wang, Rongxin; Jiang, Desheng

    2010-12-15

    There are many difficulties limiting the further development of monolithic multi-junction solar cells, such as the growth of lattice-mismatched material and the current matching constraint. As an alternative approach, the light-splitting photovoltaic system is investigated intensively in different aspects, including the energy loss mechanism and the choice of energy bandgaps of solar cells. Based on the investigation, a two-dual junction system has been implemented employing lattice-matched GaInP/GaAs and InGaAsP/InGaAs cells grown epitaxially on GaAs and InP substrates, respectively. (author)

  6. Enhanced photovoltaic performances of graphene/Si solar cells by insertion of a MoS2 thin film

    NASA Astrophysics Data System (ADS)

    Tsuboi, Yuka; Wang, Feijiu; Kozawa, Daichi; Funahashi, Kazuma; Mouri, Shinichiro; Miyauchi, Yuhei; Takenobu, Taishi; Matsuda, Kazunari

    2015-08-01

    Transition-metal dichalcogenides exhibit great potential as active materials in optoelectronic devices because of their characteristic band structure. Here, we demonstrated that the photovoltaic performances of graphene/Si Schottky junction solar cells were significantly improved by inserting a chemical vapor deposition (CVD)-grown, large MoS2 thin-film layer. This layer functions as an effective electron-blocking/hole-transporting layer. We also demonstrated that the photovoltaic properties are enhanced with the increasing number of graphene layers and the decreasing thickness of the MoS2 layer. A high photovoltaic conversion efficiency of 11.1% was achieved with the optimized trilayer-graphene/MoS2/n-Si solar cell.Transition-metal dichalcogenides exhibit great potential as active materials in optoelectronic devices because of their characteristic band structure. Here, we demonstrated that the photovoltaic performances of graphene/Si Schottky junction solar cells were significantly improved by inserting a chemical vapor deposition (CVD)-grown, large MoS2 thin-film layer. This layer functions as an effective electron-blocking/hole-transporting layer. We also demonstrated that the photovoltaic properties are enhanced with the increasing number of graphene layers and the decreasing thickness of the MoS2 layer. A high photovoltaic conversion efficiency of 11.1% was achieved with the optimized trilayer-graphene/MoS2/n-Si solar cell. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03046c

  7. Perovskite solar cells: On top of commercial photovoltaics

    NASA Astrophysics Data System (ADS)

    Albrecht, Steve; Rech, Bernd

    2017-01-01

    The efficiency of single-junction solar cells is intrinsically limited and high efficiency multi-junctions are not cost effective yet. Now, semi-transparent perovskite solar cells suggest that low cost multi-junctions could be within reach.

  8. 75 FR 61509 - Notice of Issuance of Final Determination Concerning Solar Photovoltaic Panel Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-05

    ... front end process and a back end process are performed, which takes approximately six and one half days... front end process converts bare glass tubes into functional PV cells. The back end process encapsulates... seal. The last step in the back end process is to assemble these finished modules onto a panel frame...

  9. Chloroboron (III) subnaphthalocyanine as an electron donor in bulk heterojunction photovoltaic cells.

    PubMed

    Chen, Guo; Sasabe, Hisahiro; Sano, Takeshi; Wang, Xiao-Feng; Hong, Ziruo; Kido, Junji; Yang, Yang

    2013-12-06

    In this work, chloroboron (III) subnaphthalocyanine (SubNc) was used as an electron donor, combined with a [6,6]-phenyl-C71-butyric acid methyl ester (PC70BM) or fullerene C70 acceptor in bulk heterojunction photovoltaic cells. In spite of the limited solubility of SubNc in organic solvents, the solution processed device exhibited an efficiency of 4.0% under 1 sun, AM1.5G solar irradiation at room temperature, and 5.0% at 80 ° C due to the temperature-dependence of the carrier mobilities. SubNc:C70 bulk heterojunctions were also fabricated via thermal co-evaporation, demonstrating an efficiency of 4.4%. This result shows that SubNc is a promising material for photovoltaic applications via various processing techniques, such as vacuum deposition and wet coating.

  10. Quantum Dot Sensitized Nanotubes for Full Solar Spectrum Photovoltaic Cell

    NASA Astrophysics Data System (ADS)

    Khanal, Sohana

    The demand for energy with limited non-renewable sources of energy has called researchers to find clean renewable energy sources. Solar light is considered good choice of the alternate energy. Our effort in this work was to investigate efficient photovoltaic (PV) systems by designing a hybrid photoelectrode with good absorption as well as charge transport properties. A coupled semiconductor material, one-dimensional TiO2 nanotubes (1D TiO2-NTs), filled with low band semiconductor quantum dots (QDs), PbS QDs, for better charge carrier transport was prepared and investigated. The vertically standing self assembled nanotubular array was attained by anodizing the Ti metal in two different solutions: (1) Ethylene Glycol with 0.5 wt% NH4F and 3 vol percent water and (2) 0.5M H3PO4 with 0.5 wt% NH4F. The anodized samples were annealed and then filled with the nanoparticles of other low band gap semiconductor materials. The CdS nanoparticles were used for the better understanding of the sensitizing process. The material was then switched to the PbS. As in the hypothesis, if PbS quantum dots are uniformly distributed in the 1D TiO2 Multiple Charge Carrier Generation can be created since PbS has a small band gap. A chemical bath deposition process in the presence of ultrasonic waves was adopted for the deposition of the QDs. Saturated lead sulfide solution was used as the lead source and the 0.2 M Na2S solution for the sulfur source. The process resulted in the successful uniform deposition of the PbS QDs onto the 1D TiO2 NTs. The deposited compound obeyed the stoichiometric ratio of 1:1 as desired. Photocurrent densities of 4.5 mA/cm2 was obtained, which is higher than the TiO2 alone in a polysulfide solution. PbS-TiO2 can be a suitable candidate for harvesting a broad solar spectrum as the UV-vis study proved that they absorb the light in the UV range.

  11. Polymer Hybrid Photovoltaics for Inexpensive Electricity Generation: Final Technical Report, 1 September 2001--30 April 2006

    SciTech Connect

    Carter, S. A.

    2006-07-01

    The project goal is to understand the operating mechanisms underlying the performance of polymer hybrid photovoltaics to enable the development of a photovoltaic with a maximum power conversion efficiency over cost ratio that is significantly greater than current PV technologies. Plastic or polymer-based photovoltaics can have significant cost advantages over conventional technologies in that they are compatible with liquid-based plastic processing and can be assembled onto plastic under atmospheric conditions (ambient temperature and pressure) using standard printing technologies, such as reel-to-reel and screen printing. Moreover, polymer-based PVs are lightweight, flexible, and largely unbreakable, which make shipping, installation, and maintenance simpler. Furthermore, a numerical simulation program was developed (in collaboration with IBM) to fully simulate the performance of multicomponent polymer photovoltaic devices, and a manufacturing method was developed (in collaboration with Add-vision) to inexpensively manufacture larger-area devices.

  12. Photovoltaic properties and morphology of organic solar cells based on liquid-crystal semiconducting polymer with additive

    SciTech Connect

    Suzuki, Atsushi; Zushi, Masahito; Suzuki, Hisato; Ogahara, Shinichi; Akiyama, Tsuyoshi; Oku, Takeo

    2014-02-20

    Bulk heterojunction organic solar cell based on liquid crystal semiconducting polymers of poly[9,9-dioctylfluorene-co-bithiophene] (F8T2) as p-type semiconductors and fullerenes (C{sub 60}) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as electron donor and acceptor has been fabricated and characterized for improving photovoltaic and optical properties. The photovoltaic performance including current voltage curves in the dark and illumination of the F8T2/C{sub 60} conventional and inverted bulk heterojunction solar cells were investigated. Relationship between the photovoltaic properties and morphological behavior was focused on tuning for optimization of photo-voltaic performance under annealing condition near glass transition temperature. Additive-effect of diiodooctane (DIO) and poly(3-hexylthiophene-2,5-diyl) (P3HT) on the photovoltaic performance and optical properties was investigated. Mechanism of the photovoltaic properties of the conventional and inverted solar cells will be discussed by the experimental results.

  13. Estimating cell temperature in a concentrating photovoltaic system

    NASA Astrophysics Data System (ADS)

    Yandt, M. D.; Wheeldon, J. F.; Cook, J.; Beal, R.; Walker, A. W.; Thériault, O.; Schriemer, H.; Hall, T. J.; Hinzer, K.

    2012-10-01

    A temperature calibrated equivalent circuit model of a high efficiency CPV solar cell is used to simulate a measured six-cell module J-V curve to estimate its average operating temperature. The simulation is based on a two diode equivalent circuit model for each subcell of a representative triple junction cell. Module J-V curves in a real CPV system were measured with a test station that performs continuous voltage sweeps allowing cells to reach a well defined thermal equilibrium during measurement. The average electrical power extracted during measurement is then used to determine the cell temperature when they are operating at their maximum power point. It is shown that the cells would operate at 42 ± 2 C° above ambient (32 ± 2°C abs.) given the ambient conditions during the measurement.

  14. Enhanced photovoltaic performance of an inclined nanowire array solar cell.

    PubMed

    Wu, Yao; Yan, Xin; Zhang, Xia; Ren, Xiaomin

    2015-11-30

    An innovative solar cell based on inclined p-i-n nanowire array is designed and analyzed. The results show that the inclined geometry can sufficiently increase the conversion efficiency of solar cells by enhancing the absorption of light in the active region. By tuning the nanowire array density, nanowire diameter, nanowire length, as well as the proportion of intrinsic region of the inclined nanowire solar cell, a remarkable efficiency in excess of 16% can be obtained in GaAs. Similar results have been obtained in InP and Si nanowire solar cells, demonstrating the universality of the performance enhancement of inclined nanowire arrays.

  15. Photovoltaics: The endless spring

    NASA Technical Reports Server (NTRS)

    Brandhorst, H. W., Jr.

    1984-01-01

    An overview of the developments in the photovoltaic field over the past decade or two is presented. Accomplishments in the terrestrial field are reviewed along with projections and challenges toward meeting cost goals. The contrasts and commonality of space and terrestrial photovoltaics are presented. Finally, a strategic philosophy of photovoltaics research highlighting critical factors, appropriate directions, emerging opportunities, and challenges of the future is given.

  16. Large area low cost processing for CIS photovoltaics. Final technical report

    SciTech Connect

    B. Basol; G. Norsworthy; C. Leidholm; A. Halani; R. Roe; V. Kapur

    1999-07-22

    An ink coating method was developed for CIS absorber deposition. The technique involves four processing steps: (1) preparation of a Cu-In alloy powder, (2) preparation of an ink using this powder, (3) deposition of the ink on a substrate in the form of a precursor layer, and (4) selenization to convert the Cu-In precursor into a fused CIS film. Absorbers grown by this low-cost, large-area method were used in the fabrication of 10.5% efficient solar cells.

  17. Application of digital micromirror devices for spectral-response characterization of solar cells and photovoltaics

    NASA Astrophysics Data System (ADS)

    Fong, Alexandre Y.

    2010-02-01

    A key parameter in evaluating the performance of photovoltaic (PV) solar cells is characterization of electrical response to various incident source spectra. Conventional techniques utilize monochromators that emit single band-passes across a spectral region of interest. Since many solar cells respond differently at different broadband source light levels, a white bias light source that raises the overall light level to simulate the sun's broadband emission is typically introduced. However, such sources cannot render realistic solar continua. We present some initial results demonstrating how a spectrally-dispersed broadband source modulated with Texas Instruments' Digital Light Projection (DLP®) technology can be used to more faithfully synthesize solar spectra for this application.

  18. High temperature solid oxide regenerative fuel cell for solar photovoltaic energy storage

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    1987-01-01

    A hydrogen-oxygen regenerative fuel cell energy storage system based on high temperature solid oxide fuel cell technology is discussed which has application to darkside energy storage for solar photovoltaics. The forward and reverse operating cycles are described, and heat flow, mass, and energy balance data are presented to characterize the system's performance and the variation of performance with changing reactant storage pressure. The present system weighs less than nickel hydrogen battery systems after 0.7 darkside operation, and it maintains a specific weight advantage over radioisotope generators for discharge periods up to 72 hours.

  19. High temperature solid oxide regenerative fuel cell for solar photovoltaic energy storage

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    1987-01-01

    A hydrogen-oxygen regenerative fuel cell energy storage system based on high temperature solid oxide fuel cell technology is discussed which has application to darkside energy storage for solar photovoltaics. The forward and reverse operating cycles are described, and heat flow, mass, and energy balance data are presented to characterize the system's performance and the variation of performance with changing reactant storage pressure. The present system weighs less than nickel hydrogen battery systems after 0.7 darkside operation, and it maintains a specific weight advantage over radioisotope generators for discharge periods up to 72 hours.

  20. Enhanced EOS photovoltaic power system capability with InP solar cells

    NASA Technical Reports Server (NTRS)

    Bailey, Sheila G.; Weinberg, Irving; Flood, Dennis J.

    1991-01-01

    The Earth Observing System (EOS), which is part of the International Mission to Planet Earth, is NASA's main contribution to the Global Change Research Program which opens a new era in international cooperation to study the Earth's environment. Five large platforms are to be launched into polar orbit, two by NASA, two by ESA, and one by the Japanese. In such an orbit the radiation resistance of indium phosphide solar cells combined with the potential of utilizing five micron cell structures yields an increase of 10 percent in the payload capability. If further combined with the advanced photovoltaic solar array the payload savings approaches 12 percent.

  1. Sensibilization of polymer/fullerene photovoltaic cells using Zinc Phtalocyanine studied by combinatorial technique

    NASA Astrophysics Data System (ADS)

    Godovsky, D.; Chen, L.; Petterson, L.; Inganäs, O.

    2000-11-01

    The influence of Zinc Phtalocyanine admixture to fullerene layers on top of PTOPT to the photovoltaic cells performance was studied. In order to investigate all the possible combinations of ZnPc and C60 the combinatorial technique was developed consisting in thermal co-evaporation of ZnPc and C60 from two different boats. The significant increase in solar cells photocurrent was observed, coming from ZnPc absorbance bands, especially for the layers containing 1:1 molar ratio of the components.

  2. Use of silicon photovoltaic cells to provide a second channel in flame emission photometry

    PubMed Central

    Hurst, R. J.; Bold, A. M.

    1966-01-01

    Sodium and potassium may be measured simultaneously, using a modified Eppendorf flame photometer. After automatic sampling and dilution of the plasma, the potassium content is measured, using the existing Eppendorf optical and photomultiplier system. The sodium emission is measured by three silicon photovoltaic cells mounted behind an interference filter for sodium, sited on the atomiser casing. The outputs from the photomultiplier and from the silicon cells are recorded by two sensitive recorders. Sixty samples an hour may be estimated, using only 0·12 ml. plasma. Reproducibility tests showed a coefficient of variation of 0·4%. Images PMID:5928613

  3. Fabricating high-concentration GaAs cell photovoltaic modules

    SciTech Connect

    Kaminar, N.R.; Hamaker, H.C.

    1986-04-01

    This program comprises the design and manufacture of components of a GaAs-cell, passively-cooled concentrator. A Fresnel lens, 5.44-inches square, was used in conjunction with a solid glass, domed-top secondary optical element to concentrate the light on single-junction GaAs cells. The cell had an active area 0.2 inches in diameter and was soldered directly to the copper heatspreader. The heatspreader was bonded with heat-conductive RTV to an aluminum dissipator, which formed the module housing. The module was designed to be attached to a tracker at the center. Obtained were 26% cell efficiency in flash tests and 19.2% combined lens/cell efficiency outdoors. Optical transmission was lower than expected due to higher than expected losses in the secondary. The secondaries were made using a molding technique applicable to mass production.

  4. Environmental tests of metallization systems for terrestrial photovoltaic cells

    NASA Technical Reports Server (NTRS)

    Alexander, P., Jr.

    1985-01-01

    Seven different solar cell metallization systems were subjected to temperature cycling tests and humidity tests. Temperature cycling excursions were -50 deg C to 150 deg C per cycle. Humidity conditions were 70 deg C at 98% relative humidity. The seven metallization systems were: Ti/Ag, Ti/Pd/Ag, Ti/Pd/Cu, Ni/Cu, Pd/Ni/Solder, Cr/Pd/Ag, and thick film Ag. All metallization systems showed a slight to moderate decrease in cell efficiencies after subjection to 1000 temperature cycles. Six of the seven metallization systems also evidenced slight increases in cell efficiencies after moderate numbers of cycles, generally less than 100 cycles. The copper based systems showed the largest decrease in cell efficiencies after temperature cycling. All metallization systems showed moderate to large decreases in cell efficiencies after 123 days of humidity exposure. The copper based systems again showed the largest decrease in cell efficiencies after humidity exposure. Graphs of the environmental exposures versus cell efficiencies are presented for each metallization system, as well as environmental exposures versus fill factors or series resistance.

  5. The Influence of Substituent Orientation on the Photovoltaic Performance of Phthalocyanine-Sensitized Solar Cells.

    PubMed

    Tejerina, Lara; Martínez-Díaz, M Victoria; Nazeeruddin, Mohammad Khaja; Torres, Tomas

    2016-03-18

    Phthalocyanines (Pcs) are used as sensitizers in dye-sensitized solar cells (DSSCs) because of their stability and intense absorption in the red and near-IR regions. Impressive progress has been made in photovoltaic efficiencies by introduction of bulky peripheral substituents to help suppress macrocycle aggregation. To reach benchmark efficiencies reported for other related dyes, new designs need to be explored. Single carboxy-ZnPc regioisomers substituted at the non-peripheral positions by rigid aryl groups have now been studied, which has shed light on the influence of steric hindrance and/or orientation of the substituent around the anchoring group on the photovoltaic response. The regioisomer bearing the aryl group far away from the anchoring group produces a more effective sensitization of the TiO2 films and higher short-circuit photocurrent density (Jsc). Taking advantage of the good photovoltaic performance in the near-IR region of this ZnPc, it was combined with another appropriate dye for panchromatic sensitization of the mesoporous photoelectrode and an increase of the overall device efficiency.

  6. Influences of device structures on microstructure-correlated photovoltaic characteristics of organic solar cells

    NASA Astrophysics Data System (ADS)

    Wu, Fu-Chiao; Yang, Cheng-Chi; Tseng, Po-Tsung; Chou, Wei-Yang; Cheng, Horng-Long

    2017-02-01

    Photovoltaic characteristics of organic solar cells (OSCs) are correlated with microstructural qualities of active layers (ALs). Numerous efforts focused on improving process conditions of ALs to attain effective microstructures to achieve high-efficiency OSCs. Aside from AL process conditions, layer properties under AL can also influence microstructural qualities of AL. In this study, we adopted poly(3-hexylthiophene) (P3HT):(6,6)-phenyl C61-butyric acid methyl ester (PCBM) mixture as AL, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as hole extraction layer, and branched polyethyleneimine (BPEI) as electron extraction layer to prepare OSCs with different device structures, that is, normal type (PEDOT:PSS/P3HT:PCBM/BPEI) and inverted type (BPEI/P3HT:PCBM/PEDOT:PSS) structures. We discovered that although devices have similar layer components, they have different photovoltaic characteristics. Inverted devices demonstrated higher power conversion efficiency than normal devices. Various methods, including absorption spectroscopy and microscopy, were used to study AL microstructures of different devices. We observed that P3HT crystallites grown on BPEI had longer vertical size and shorter horizontal size compared with those grown on PEDOT:PSS; these properties could result from larger interfacial tension of P3HT with BPEI than with PEDOT:PSS. Observed shape of P3HT crystallites in inverted devices facilitated efficient charge transport to electrodes and suppressed current leakage. As a result, inverted devices generated improved photovoltaic performance.

  7. Global optimization of silicon photovoltaic cell front coatings.

    PubMed

    Ghebrebrhan, Michael; Bermel, Peter; Avniel, Yehuda; Joannopoulos, John D; Johnson, Steven G

    2009-04-27

    The front-coating (FC) of a solar cell controls its efficiency, determining admission of light into the absorbing material and potentially trapping light to enhance thin absorbers. Single-layer FC designs are well known, especially for thick absorbers where their only purpose is to reduce reflections. Multilayer FCs could improve performance, but require global optimization to design. For narrow bandwidths, one can always achieve nearly 100% absorption. For the entire solar bandwidth, however, a second FC layer improves performance by 6.1% for 256 microm wafer-based cells, or by 3.6% for 2 microm thin-film cells, while additional layers yield rapidly diminishing returns.

  8. Assessing the Performance of the Photovoltaic Cells on the Effects of Yellow Dust Events and Haze in Seoul, Korea

    NASA Astrophysics Data System (ADS)

    Choi, Jiyeon; Kim, Yong Pyo; Wee, DaeHyun

    2016-04-01

    We analyze the potential effects of the Asian yellow dust Events and haze on the performance of Korean photovoltaic systems. Particulate matters from the Asian yellow dust outbreaks in the deserts of Mongolia and northern China are typically transported to Korea. Haze is an atmospheric phenomenon where dust, smoke and other dry particles obscure the clarity of the sky. Hence, we conjecture that the effects of the Asian yellow dust and haze block the incident solar irradiance. The potential reduction of the solar spectral irradiance due to Asian yellow dust events and haze in Korea is investigated using a clear-sky spectral radiation model, and the performance of photovoltaic systems under reduced irradiance is estimated by using a simple analytic model representing typical photovoltaic cells. Comparison of photovoltaic performance under Asian dust events, haze and that under a clear condition is made to evaluate overall influence of the particulate air pollution, respectively.

  9. A thermo-electric system using concentrated solar energy with photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Wong, K.-F. V.; Dorney, S.

    The work reported here is a preliminary study of a thermo-electric system using concentrated solar radiation with photovoltaic cells. The system incorporated a novel concentrating system with the designed purpose of utilizing those portions of the solar spectrum that the silicon solar cells were not responsive to. The experimental set-up consisted of a 3.8 cm diameter glass tube, 76.2 cm long with the glass silicon cells positioned at equal intervals on its underside. Fresnel lenses were placed so that the incoming solar radiation was concentrated onto the silicon cells. The glass tube was filled with water which absorbed energy from the solar radiation before it reached the cells. The water had its temperature raised nine degrees Fahrenheit while also allowing the solar cells to produce approximately 0.05 watt. This results in an efficiency of around 35 percent. The results obtained are preliminary, and represent typical conditions in south Florida.

  10. Thermal analysis of a multi-layer microchannel heat sink for cooling concentrator photovoltaic (CPV) cells

    NASA Astrophysics Data System (ADS)

    Siyabi, Idris Al; Shanks, Katie; Mallick, Tapas; Sundaram, Senthilarasu

    2017-09-01

    Concentrator Photovoltaic (CPV) technology is increasingly being considered as an alternative option for solar electricity generation. However, increasing the light concentration ratio could decrease the system output power due to the increase in the temperature of the cells. The performance of a multi-layer microchannel heat sink configuration was evaluated using numerical analysis. In this analysis, three dimensional incompressible laminar steady flow model was solved numerically. An electrical and thermal solar cell model was coupled for solar cell temperature and efficiency calculations. Thermal resistance, solar cell temperature and pumping power were used for the system efficiency evaluation. An increase in the number of microchannel layers exhibited the best overall performance in terms of the thermal resistance, solar cell temperature uniformity and pressure drop. The channel height and width has no effect on the solar cell maximum temperature. However, increasing channel height leads to a reduction in the pressure drop and hence less fluid pumping power.

  11. Photovoltaic Roofs

    NASA Technical Reports Server (NTRS)

    Drummond, R. W., Jr.; Shepard, N. F., Jr.

    1984-01-01

    Solar cells perform two functions: waterproofing roof and generating electricity. Sections through horizontal and slanting joints show overlapping modules sealed by L-section rubber strips and side-by-side modules sealed by P-section strips. Water seeping through seals of slanting joints drains along channels. Rooftop photovoltaic array used watertight south facing roof, replacing shingles, tar, and gravel. Concept reduces cost of residential solar-cell array.

  12. Simple Photovoltaic Cells for Exploring Solar Energy Concepts

    ERIC Educational Resources Information Center

    Appleyard, S. J.

    2006-01-01

    Low-efficiency solar cells for educational purposes can be simply made in school or home environments using wet-chemistry techniques and readily available chemicals of generally low toxicity. Instructions are given for making solar cells based on the heterojunctions Cu/Cu[subscript 2]O, Cu[subscript 2]O/ZnO and Cu[subscript 2]S/ZnO, together with…

  13. Simple Photovoltaic Cells for Exploring Solar Energy Concepts

    ERIC Educational Resources Information Center

    Appleyard, S. J.

    2006-01-01

    Low-efficiency solar cells for educational purposes can be simply made in school or home environments using wet-chemistry techniques and readily available chemicals of generally low toxicity. Instructions are given for making solar cells based on the heterojunctions Cu/Cu[subscript 2]O, Cu[subscript 2]O/ZnO and Cu[subscript 2]S/ZnO, together with…

  14. Low cost silicon-on-ceramic photovoltaic solar cells

    NASA Technical Reports Server (NTRS)

    Koepke, B. G.; Heaps, J. D.; Grung, B. L.; Zook, J. D.; Sibold, J. D.; Leipold, M. H.

    1980-01-01

    A technique has been developed for coating low-cost mullite-based refractory substrates with thin layers of solar cell quality silicon. The technique involves first carbonizing one surface of the ceramic and then contacting it with molten silicon. The silicon wets the carbonized surface and, under the proper thermal conditions, solidifies as a large-grained sheet. Solar cells produced from this composite silicon-on-ceramic material have exhibited total area conversion efficiencies of ten percent.

  15. Organic and hybrid organic-inorganic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    McGehee, Michael

    2011-03-01

    The performance and limitations of the world's best organic and dye sensitized solar cells will be presented along with plans to increase the energy conversion efficiency to 15%. Topics of more detailed discussion could include the formation of polymer-fullerene co-crystals and their implications for recombination, the use of energy transfer to improve light harvesting~in~dye sensitized solar cells, solution deposited transparent electrodes or the use of plasmonics to improve light absorption.

  16. High-efficiency thin and compact concentrator photovoltaics using micro-solar cells with via-holes sandwiched between thin lens-array and circuit board

    NASA Astrophysics Data System (ADS)

    Itou, Akihiro; Asano, Tetsuya; Inoue, Daijiro; Arase, Hidekazu; Matsushita, Akio; Hayashi, Nobuhiko; Futakuchi, Ryutaro; Inoue, Kazuo; Yamamoto, Masaki; Fujii, Eiji; Nakagawa, Tohru; Anda, Yoshiharu; Ishida, Hidetoshi; Ueda, Tetsuzo; Fidaner, Onur; Wiemer, Michael; Ueda, Daisuke

    2014-01-01

    We have developed a compact concentrator photovoltaic (CPV) module that comprises micro-solar cells with an area of ≈0.6 × 0.6 mm2 sandwiched between a 20-mm-thick lens array and a 1-mm-thick circuit board with no air gap. To establish electrical connections between the circuit board and the micro-solar cells, we developed a micro-solar cell with positive and negative electrodes on the lower face of the cell. In this study, we demonstrated the photovoltaic performance of the micro-solar cell closely approaches that of the standard solar cell measuring ≈5 × 5 mm2 commonly used in conventional CPVs under concentrated illumination. Our study showed that the negative effect on PV performance of perimeter carrier recombination in the micro-solar cell was insignificant under concentrated illumination. Finally, we assembled our micro-solar cells into a CPV module and achieved the module energy conversion efficiency of 34.7% under outdoor solar illumination.

  17. Photon management modeling and beyond for photovoltaics

    NASA Astrophysics Data System (ADS)

    Bermel, Peter

    2014-03-01

    Improving the performance of photovoltaics is important for increased deployment in a broad range of applications. In this article, it is shown that combining detailed models for full-wave optics with one or more other physics models represents an emerging field of research. In particular, connections are made with geometric optics, electronic transport, and thermal transport. First, structures combining random texturing and periodic gratings offer the promise of higher light-trapping performance for a broad range of thin-film photovoltaic systems. Second, combining full-wave optics with electronic transport creates an opportunity to accurately model the limits of performance for devices approaching the Shockley-Queisser limit. Finally, combining optical with thermal modeling creates the potential for a physics-based understanding of intrinsic photovoltaic module failures, necessary to ensure a long life for photovoltaic cells.

  18. Photovoltaics. Interface engineering of highly efficient perovskite solar cells.

    PubMed

    Zhou, Huanping; Chen, Qi; Li, Gang; Luo, Song; Song, Tze-bing; Duan, Hsin-Sheng; Hong, Ziruo; You, Jingbi; Liu, Yongsheng; Yang, Yang

    2014-08-01

    Advancing perovskite solar cell technologies toward their theoretical power conversion efficiency (PCE) requires delicate control over the carrier dynamics throughout the entire device. By controlling the formation of the perovskite layer and careful choices of other materials, we suppressed carrier recombination in the absorber, facilitated carrier injection into the carrier transport layers, and maintained good carrier extraction at the electrodes. When measured via reverse bias scan, cell PCE is typically boosted to 16.6% on average, with the highest efficiency of ~19.3% in a planar geometry without antireflective coating. The fabrication of our perovskite solar cells was conducted in air and from solution at low temperatures, which should simplify manufacturing of large-area perovskite devices that are inexpensive and perform at high levels. Copyright © 2014, American Association for the Advancement of Science.

  19. Assessing corrosion problems in photovoltaic cells via electrochemical stress testing

    NASA Technical Reports Server (NTRS)

    Shalaby, H.

    1985-01-01

    A series of accelerated electrochemical experiments to study the degradation properties of polyvinylbutyral-encapsulated silicon solar cells has been carried out. The cells' electrical performance with silk screen-silver and nickel-solder contacts was evaluated. The degradation mechanism was shown to be electrochemical corrosion of the cell contacts; metallization elements migrate into the encapsulating material, which acts as an ionic conducting medium. The corrosion products form a conductive path which results in a gradual loss of the insulation characteristics of the encapsulant. The precipitation of corrosion products in the encapsulant also contributes to its discoloration which in turn leads to a reduction in its transparency and the consequent optical loss. Delamination of the encapsulating layers could be attributed to electrochemical gas evolution reactions. The usefulness of the testing technique in qualitatively establishing a reliability difference between metallizations and antireflection coating types is demonstrated.

  20. Assessing corrosion problems in photovoltaic cells via electrochemical stress testing

    NASA Technical Reports Server (NTRS)

    Shalaby, H.

    1985-01-01

    A series of accelerated electrochemical experiments to study the degradation properties of polyvinylbutyral-encapsulated silicon solar cells has been carried out. The cells' electrical performance with silk screen-silver and nickel-solder contacts was evaluated. The degradation mechanism was shown to be electrochemical corrosion of the cell contacts; metallization elements migrate into the encapsulating material, which acts as an ionic conducting medium. The corrosion products form a conductive path which results in a gradual loss of the insulation characteristics of the encapsulant. The precipitation of corrosion products in the encapsulant also contributes to its discoloration which in turn leads to a reduction in its transparency and the consequent optical loss. Delamination of the encapsulating layers could be attributed to electrochemical gas evolution reactions. The usefulness of the testing technique in qualitatively establishing a reliability difference between metallizations and antireflection coating types is demonstrated.

  1. Hybrid Organic/Inorganic Nanocomposites for Photovoltaic Cells

    PubMed Central

    Liu, Ruchuan

    2014-01-01

    Inorganic/organic hybrid solar cells have attracted a lot of interest due to their potential in combining the advantages of both components. To understand the key issues in association with photoinduced charge separation/transportation processes and to improve overall power conversion efficiency, various combinations with nanostructures of hybrid systems have been investigated. Here, we briefly review the structures of hybrid nanocomposites studied so far, and attempt to associate the power conversion efficiency with these nanostructures. Subsequently, we are then able to summarize the factors for optimizing the performance of inorganic/organic hybrid solar cells. PMID:28788591

  2. Space Solar Cell Research and Development Projects at Emcore Photovoltaics

    NASA Technical Reports Server (NTRS)

    Sharps, Paul; Aiken,Dan; Stan, Mark; Cornfeld, Art; Newman, Fred; Endicter, Scott; Girard, Gerald; Doman, John; Turner, Michele; Sandoval, Annette; hide

    2007-01-01

    The GaInP2/InGaAs/Ge triple junction device lattice matched to germanium has achieved the highest power conversion efficiency and the most commercial success for space applications [1]. What are the practical performance limits of this technology? In this paper we will describe what we consider to be the practical performance limits of the lattice matched GaInP2/InGaAs/Ge triple junction cell. In addition, we discuss the options for next generation space cell performance.

  3. Optimal design of bandpass filters to reduce emission from photovoltaic cells under monochromatic illumination

    NASA Astrophysics Data System (ADS)

    Takeda, Yasuhiko; Iizuka, Hideo; Ito, Tadashi; Mizuno, Shintaro; Hasegawa, Kazuo; Ichikawa, Tadashi; Ito, Hiroshi; Kajino, Tsutomu; Higuchi, Kazuo; Ichiki, Akihisa; Motohiro, Tomoyoshi

    2015-08-01

    We have theoretically investigated photovoltaic cells used under the illumination condition of monochromatic light incident from a particular direction, which is very different from that for solar cells under natural sunlight, using detailed balance modeling. A multilayer bandpass filter formed on the surface of the cell has been found to trap the light generated by radiative recombination inside the cell, reduce emission from the cell, and consequently improve conversion efficiency. The light trapping mechanism is interpreted in terms of a one-dimensional photonic crystal, and the design guide to optimize the multilayer structure has been clarified. For obliquely incident illumination, as well as normal incidence, a significant light trapping effect has been achieved, although the emission patterns are extremely different from each other depending on the incident directions.

  4. Flat plate vs. concentrator solar photovoltaic cells - A manufacturing cost analysis

    NASA Technical Reports Server (NTRS)

    Granon, L. A.; Coleman, M. G.

    1980-01-01

    The choice of which photovoltaic system (flat plate or concentrator) to use for utilizing solar cells to generate electricity depends mainly on the cost. A detailed, comparative manufacturing cost analysis of the two types of systems is presented. Several common assumptions, i.e., cell thickness, interest rate, power rate, factory production life, polysilicon cost, and direct labor rate are utilized in this analysis. Process sequences, cost variables, and sensitivity analyses have been studied, and results of the latter show that the most important parameters which determine manufacturing costs are concentration ratio, manufacturing volume, and cell efficiency. The total cost per watt of the flat plate solar cell is $1.45, and that of the concentrator solar cell is $1.85, the higher cost being due to the increased process complexity and material costs.

  5. Real Time Optics of the Growth of Textured Silicon Films in Photovoltaics: Final Technical Report, 1 August 1999--12 August 2002

    SciTech Connect

    Collins, R. W.; Wronski, C. R.

    2003-10-01

    Novel optical instruments, including single and dual rotating-compensator multichannel ellipsometers, have been designed and developed to probe the evolution of the microstructure, spectroscopic optical properties, and other materials characteristics during the fabrication and processing of individual thin films and thin-film structures used in photovoltaic devices. These instruments provide a foundation for next-generation process design/control and metrology in existing and future photovoltaics technologies. In this project, the materials system studied in the greatest detail was thin-film silicon, fabricated at low temperatures by plasma-enhanced chemical vapor deposition. Real-time measurements of such thin films by multichannel ellipsometry have established deposition phase diagrams that provide guiding principles for multistep fabrication of high-performance amorphous (a-Si:H) and microcrystalline (mc-Si:H) solar cells. Such phase diagrams have also served to disprove conventional wisdom in the fabrication of thin-film solar cell structures, thus avoiding future unproductive research efforts.

  6. Deliberate Design of TiO2 Nanostructures towards Superior Photovoltaic Cells.

    PubMed

    Sun, Ziqi; Liao, Ting; Sheng, Liyuan; Kou, Liangzhi; Kim, Jung Ho; Dou, Shi Xue

    2016-08-01

    TiO2 nanostructures are being sought after as flexibly utilizable building blocks for the fabrication of the mesoporous thin-film photoelectrodes that are the heart of the third-generation photovoltaic devices, such as dye-sensitized solar cells (DSSCs), quantum-dot-sensitized solar cells (QDSSCs), and the recently promoted perovskite-type solar cells. Here, we report deliberate tailoring of TiO2 nanostructures for superior photovoltaic cells. Morphology engineering of TiO2 nanostructures is realized by designing synthetic protocols in which the precursor hydrolysis, crystal growth, and oligomer self-organization are precisely controlled. TiO2 nanostructures in forms varying from isolated nanocubes, nanorods, and cross-linked nanorods to complex hierarchical structures and shape-defined mesoporous micro-/nanostructures were successfully synthesized. The photoanodes made from the shape-defined mesoporous TiO2 microspheres and nanospindles presented superior performances, owing to the well-defined overall shapes and the inner ordered nanochannels, which allow not only a high amount of dye uptake, but also improved visible-light absorption. This study provides a new way to seek an optimal synthetic protocol to meet the required functionality of the nanomaterials.

  7. Printable nanostructured silicon solar cells for high-performance, large-area flexible photovoltaics.

    PubMed

    Lee, Sung-Min; Biswas, Roshni; Li, Weigu; Kang, Dongseok; Chan, Lesley; Yoon, Jongseung

    2014-10-28

    Nanostructured forms of crystalline silicon represent an attractive materials building block for photovoltaics due to their potential benefits to significantly reduce the consumption of active materials, relax the requirement of materials purity for high performance, and hence achieve greatly improved levelized cost of energy. Despite successful demonstrations for their concepts over the past decade, however, the practical application of nanostructured silicon solar cells for large-scale implementation has been hampered by many existing challenges associated with the consumption of the entire wafer or expensive source materials, difficulties to precisely control materials properties and doping characteristics, or restrictions on substrate materials and scalability. Here we present a highly integrable materials platform of nanostructured silicon solar cells that can overcome these limitations. Ultrathin silicon solar microcells integrated with engineered photonic nanostructures are fabricated directly from wafer-based source materials in configurations that can lower the materials cost and can be compatible with deterministic assembly procedures to allow programmable, large-scale distribution, unlimited choices of module substrates, as well as lightweight, mechanically compliant constructions. Systematic studies on optical and electrical properties, photovoltaic performance in experiments, as well as numerical modeling elucidate important design rules for nanoscale photon management with ultrathin, nanostructured silicon solar cells and their interconnected, mechanically flexible modules, where we demonstrate 12.4% solar-to-electric energy conversion efficiency for printed ultrathin (∼ 8 μm) nanostructured silicon solar cells when configured with near-optimal designs of rear-surface nanoposts, antireflection coating, and back-surface reflector.

  8. InGaAsP/InGaAs tandem photovoltaic devices for four-junction solar cells

    NASA Astrophysics Data System (ADS)

    Yongming, Zhao; Jianrong, Dong; Kuilong, Li; Yurun, Sun; Xulu, Zeng; Yang, He; Shuzhen, Yu; Hui, Yang

    2015-04-01

    Lattice-matched InGaAs(P) photovoltaic devices were grown on InP substrates by metal-organic chemical vapor deposition. InGaAsP/InGaAs (1.07/0.74 eV) dual-junction (DJ) solar cells were fabricated and characterized by quantum efficiency and I-V measurements. The open circuit voltage, short circuit current density, fill factor, and efficiency of InGaAsP/InGaAs DJ solar cell are 0.977 V, 10.2 mA/cm2, 80.8%, and 8.94%, respectively, under one sun illumination of the AM 1.5D spectrum. For the InGaAsP/InGaAs DJ solar cell, with increasing concentration, the conversion efficiency first increases steadily and reaches 13% around 280 suns, and finally decreases due to the drop in fill factor at higher concentration ratios. These experimental results demonstrate the promising prospect of GaInP/GaAs/InGaAsP/InGaAs four-junction solar cells. Project supported by the National Natural Science Foundation of China (No. 61376065).

  9. Thick-film materials for silicon photovoltaic cell manufacture

    NASA Technical Reports Server (NTRS)

    Field, M. B.

    1977-01-01

    Thick film technology is applicable to three areas of silicon solar cell fabrication; metallization, junction formation, and coating for protection of screened ohmic contacts, particularly wrap around contacts, interconnection and environmental protection. Both material and process parameters were investigated. Printed ohmic contacts on n- and p-type silicon are very sensitive to the processing parameters of firing time, temperature, and atmosphere. Wrap around contacts are easily achieved by first printing and firing a dielectric over the edge and subsequently applying a low firing temperature conductor. Interconnection of cells into arrays can be achieved by printing and cofiring thick film metal pastes, soldering, or with heat curing conductive epoxies on low cost substrates. Printed (thick) film vitreous protection coatings do not yet offer sufficient optical uniformity and transparency for use on silicon. A sprayed, heat curable SiO2 based resin shows promise of providing both optical matching and environmental protection.

  10. Optical Frequency Optimization of a High Intensity Laser Power Beaming System Utilizing VMJ Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Raible, Daniel E.; Dinca, Dragos; Nayfeh, Taysir H.

    2012-01-01

    An effective form of wireless power transmission (WPT) has been developed to enable extended mission durations, increased coverage and added capabilities for both space and terrestrial applications that may benefit from optically delivered electrical energy. The high intensity laser power beaming (HILPB) system enables long range optical 'refueling" of electric platforms such as micro unmanned aerial vehicles (MUAV), airships, robotic exploration missions and spacecraft platforms. To further advance the HILPB technology, the focus of this investigation is to determine the optimal laser wavelength to be used with the HILPB receiver, which utilizes vertical multi-junction (VMJ) photovoltaic cells. Frequency optimization of the laser system is necessary in order to maximize the conversion efficiency at continuous high intensities, and thus increase the delivered power density of the HILPB system. Initial spectral characterizations of the device performed at the NASA Glenn Research Center (GRC) indicate the approximate range of peak optical-to-electrical conversion efficiencies, but these data sets represent transient conditions under lower levels of illumination. Extending these results to high levels of steady state illumination, with attention given to the compatibility of available commercial off-the-shelf semiconductor laser sources and atmospheric transmission constraints is the primary focus of this paper. Experimental hardware results utilizing high power continuous wave (CW) semiconductor lasers at four different operational frequencies near the indicated band gap of the photovoltaic VMJ cells are presented and discussed. In addition, the highest receiver power density achieved to date is demonstrated using a single photovoltaic VMJ cell, which provided an exceptionally high electrical output of 13.6 W/sq cm at an optical-to-electrical conversion efficiency of 24 percent. These results are very promising and scalable, as a potential 1.0 sq m HILPB receiver of

  11. Polymer Photovoltaic Cells with Rhenium Oxide as Anode Interlayer

    PubMed Central

    Wei, Jinyu; Bai, Dongdong; Yang, Liying

    2015-01-01

    The effect of a new transition metal oxide, rhenium oxide (ReO3), on the performance of polymer solar cells based on regioregular poly(3-hexylthiophene) (P3HT) and methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM) blend as buffer layer was investigated. The effect of the thickness of ReO3 layer on electrical characteristics of the polymer solar cells was studied. It is found that insertion of ReO3 interfacial layer results in the decreased performance for P3HT: PCBM based solar cells. In order to further explore the mechanism of the decreasing of the open-circuit voltage (Voc), the X-ray photoelectron spectroscopy (XPS) is used to investigate the ReO3 oxidation states. Kelvin Probe method showed that the work function of the ReO3 is estimated to be 5.13eV after thermal evaporation. The results indicated the fact that a portion of ReO3 decomposed during thermal evaporation process, resulting in the formation of a buffer layer with a lower work function. As a consequence, a higher energy barrier was generated between the ITO and the active layer. PMID:26226439

  12. Polymer Photovoltaic Cells with Rhenium Oxide as Anode Interlayer.

    PubMed

    Wei, Jinyu; Bai, Dongdong; Yang, Liying

    2015-01-01

    The effect of a new transition metal oxide, rhenium oxide (ReO3), on the performance of polymer solar cells based on regioregular poly(3-hexylthiophene) (P3HT) and methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM) blend as buffer layer was investigated. The effect of the thickness of ReO3 layer on electrical characteristics of the polymer solar cells was studied. It is found that insertion of ReO3 interfacial layer results in the decreased performance for P3HT: PCBM based solar cells. In order to further explore the mechanism of the decreasing of the open-circuit voltage (Voc), the X-ray photoelectron spectroscopy (XPS) is used to investigate the ReO3 oxidation states. Kelvin Probe method showed that the work function of the ReO3 is estimated to be 5.13eV after thermal evaporation. The results indicated the fact that a portion of ReO3 decomposed during thermal evaporation process, resulting in the formation of a buffer layer with a lower work function. As a consequence, a higher energy barrier was generated between the ITO and the active layer.

  13. II-IV-V Based Thin Film Tandem Photovoltaic Cell

    SciTech Connect

    Newman, Nathan; van Schilfgaarde, Mark

    2012-10-04

    [Through a combination of theory and experiment that, absent unknown mitigating factors, a tandem cell whose (wide-gap. 1.8 eV) top layer is made of ZnSnP2 and whose (narrow gap, 1.1 eV) bottom layer consisting of ZnGeAs2 are near-ideal materials for a tandem cell. Not only are there gaps optimally adjusted to the solar spectrum, but the two compounds are lattice-matched, and their energy band structure and optical absorption are also near-ideal (they closely resemble that of GaAs). Our first major challenge is to establish that high-quality II-IV-V thin films can be synthesized. We have begun growing and characterizing films of ZnGeAs2 and ZnSnP2, initially grown on Ge substrates (the lattice constant of Ge matches these compounds) by pulsed laser ablation and sputtering. In tandem are theoretical calculations to guide the experiments. The goal is to develop methods that can be used to produce a pair of lattice-matched thin films that will be useful in tandem cells.

  14. How Important Is the Organic Part of Lead Halide Perovskite Photovoltaic Cells? Efficient CsPbBr3 Cells.

    PubMed

    Kulbak, Michael; Cahen, David; Hodes, Gary

    2015-07-02

    Hybrid organic-inorganic lead halide perovskite photovoltaic cells have already surpassed 20% conversion efficiency in the few years that they have been seriously studied. However, many fundamental questions still remain unanswered as to why they are so good. One of these is "Is the organic cation really necessary to obtain high quality cells?" In this study, we show that an all-inorganic version of the lead bromide perovskite material works equally well as the organic one, in particular generating the high open circuit voltages that are an important feature of these cells.

  15. PVT -- A photovoltaic/thermal concentrator total energy system: Final phase 1 project report. Building opportunities in the U.S. for photovoltaics (PV:BONUS) Two

    SciTech Connect

    1998-12-31

    United Solar completed its Phase 1 report and its proposal for Phase 2 of the PVBONUS Two program at the end of March 1998. At the same time, it also completed and submitted a proposal to the California Energy Commission PIER program for additional funding to cost-share development and testing of a pre-production model of the PVT-14. It was unsuccessful in both of these proposed efforts. While waiting for the proposal decisions, work continued in April and May to analyze the system design and component decisions described below. This document is a final summation report on the Phase 1 effort of the PVBONUS Two program that describes the key technical issues that United Solar and its subcontractor, Industrial Solar Technology Corporation, worked on in preparation of a Phase 2 award. The decisions described were ones that will guide the design and fabrication of a pre-production prototype of a 1500:1 mirrored concentrator with gallium arsenide cells when United solar resumes its development work. The material below is organized by citing the key components that underwent a design review, what the company considered, what was decided, the name of the expected supplier, if not to be produced in-house, and some information about expected costs. The cost figures given are usually budgetary estimates, not the result of firm quotations or extensive analysis.

  16. Space satellite power system. [conversion of solar energy by photovoltaic solar cell arrays

    NASA Technical Reports Server (NTRS)

    Glaser, P. E.

    1974-01-01

    The concept of a satellite solar power station was studied. It is shown that it offers the potential to meet a significant portion of future energy needs, is pollution free, and is sparing of irreplaceable earth resources. Solar energy is converted by photovoltaic solar cell arrays to dc energy which in turn is converted into microwave energy in a large active phased array. The microwave energy is beamed to earth with little attenuation and is converted back to dc energy on the earth. Economic factors are considered.

  17. Advances in thin-film solar cells for lightweight space photovoltaic power

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Bailey, Sheila G.; Flood, Dennis J.

    1989-01-01

    The development of photovoltaic arrays beyond the next generation is discussed with attention given to the potentials of thin-film polycrystalline and amorphous cells. Of particular importance is the efficiency (the fraction of incident solar energy converted to electricity) and specific power (power to weight ratio). It is found that the radiation tolerance of thin-film materials is far greater than that of single crystal materials. CuInSe2 shows no degradation when exposed to 1-MeV electrons.

  18. Intermediate-band dynamics of quantum dots solar cell in concentrator photovoltaic modules

    PubMed Central

    Sogabe, Tomah; Shoji, Yasushi; Ohba, Mitsuyoshi; Yoshida, Katsuhisa; Tamaki, Ryo; Hong, Hwen-Fen; Wu, Chih-Hung; Kuo, Cherng-Tsong; Tomić, Stanko; Okada, Yoshitaka

    2014-01-01

    We report for the first time a successful fabrication and operation of an InAs/GaAs quantum dot based intermediate band solar cell concentrator photovoltaic (QD-IBSC-CPV) module to the IEC62108 standard with recorded power conversion efficiency of 15.3%. Combining the measured experimental results at Underwriters Laboratory (UL®) licensed testing laboratory with theoretical simulations, we confirmed that the operational characteristics of the QD-IBSC-CPV module are a consequence of the carrier dynamics via the intermediate-band at room temperature. PMID:24762433

  19. An improved model and parameters extraction for photovoltaic cells using only three state points at standard test condition

    NASA Astrophysics Data System (ADS)

    Peng, Lele; Sun, Yize; Meng, Zhuo

    2014-02-01

    In this paper, a comprehensive modeling and parameters extraction method is proposed to describe the current-voltage and power-voltage characteristic of photovoltaic cells. This method is based on data commonly issued by commercial photovoltaic data sheet. By using Lambert W function, the improved model of solar cells is given. Meanwhile, the current-voltage and power-voltage curves of photovoltaic cells are calculated. To extract the model parameters from only three state points at standard test conditions, an optimized approach using iterative method and approximate method is presented. Compared to the popular Rp model and experimental data, the proposed method shows excellent agreement between the current-voltages points. It is found that the proposed modeling and parameters extraction method has less error at the maximum power point state. Moreover, the proposed model is more realistic when subjected to ideality factors variations.

  20. Solvent effects of a dimethyldicyanoquinonediimine buffer layer as N-type material on the performance of organic photovoltaic cells.

    PubMed

    Yang, Eui Yeol; Oh, Se Young

    2014-08-01

    In the present work, we have fabricated organic photovoltaic cells consisting of ITO/PEDOT:PSS/P3HT:PCBM/DMDCNQI/Al using a dip-coating method with various solvent systems. We have investigated solvent effects (such as solubility, viscosity and vapor pressure) in deposition of a thin DMDCNQI buffer layer on the performance of organic photovoltaic cells. The solvent system which had low viscosity and good solubility properties, made a dense and uniform DMDCNQI ultra thin film, resulting in a high performance device. In particular, a prepared organic photovoltaic cell was fabricated using a cosolvent system (methanol:methylenechloride = 3:1) and showed a maximum power conversion efficiency of 4.53%.

  1. Atom-probe tomographic study of interfaces of Cu{sub 2}ZnSnS{sub 4} photovoltaic cells

    SciTech Connect

    Tajima, S. Asahi, R.; Itoh, T.; Hasegawa, M.; Ohishi, K.; Isheim, D.; Seidman, D. N.

    2014-09-01

    The heterophase interfaces between the CdS buffer layer and the Cu{sub 2}ZnSnS{sub 4} (CZTS) absorption layers are one of the main factors affecting photovoltaic performance of CZTS cells. We have studied the compositional distributions at heterophase interfaces in CZTS cells using three-dimensional atom-probe tomography. The results demonstrate: (a) diffusion of Cd into the CZTS layer; (b) segregation of Zn at the CdS/CZTS interface; and (c) a change of oxygen and hydrogen concentrations in the CdS layer depending on the heat treatment. Annealing at 573 K after deposition of CdS improves the photovoltaic properties of CZTS cells probably because of the formation of a heterophase epitaxial junction at the CdS/CZTS interface. Conversely, segregation of Zn at the CdS/CZTS interface after annealing at a higher temperature deteriorates the photovoltaic properties.

  2. Preliminary Findings of the Photovoltaic Cell Calibration Experiment on Pathfinder Flight 95-3

    NASA Technical Reports Server (NTRS)

    Vargas-Aburto, Carlos

    1997-01-01

    The objective of the photovoltaic (PV) cell calibration experiment for Pathfinder was to develop an experiment compatible with an ultralight UAV to predict the performance of PV cells at AM0, the solar spectrum in space, using the Langley plot technique. The Langley plot is a valuable technique for this purpose and requires accurate measurements of air mass (pressure), cell temperature, solar irradiance, and current-voltage(IV) characteristics with the cells directed normal to the direct ray of the sun. Pathfinder's mission objective (95-3) of 65,000 ft. maximum altitude, is ideal for performing the Langley plot measurements. Miniaturization of electronic data acquisition equipment enabled the design and construction of an accurate and light weight measurement system that meets Pathfinder's low payload weight requirements.

  3. Radioisotope thermal photovoltaic application of the GaSb solar cell

    NASA Technical Reports Server (NTRS)

    Morgan, M. D.; Horne, W. E.; Day, A. C.

    1991-01-01

    An examination of a RTVP (radioisotopic thermophotovoltaic) conceptual design has shown a high potential for power densities well above those achievable with radioisotopic thermoelectric generator (RTG) systems. An efficiency of 14.4 percent and system specific power of 9.25 watts/kg were predicted for a system with sixteen GPHS (general purpose heat source) sources operating at 1100 C. The models also showed a 500 watt system power by the strontium-90 isotope at 1200 C at an efficiency of 17.0 percent and a system specific power of 11.8 watts/kg. The key to this level of performance is a high-quality photovoltaic cell with narrow bandgap and a reflective rear contact. Recent work at Boeing on GaSb cells and transparent back GaAs cells indicate that such a cell is well within reach.

  4. Light trapping for emission from a photovoltaic cell under normally incident monochromatic illumination

    NASA Astrophysics Data System (ADS)

    Takeda, Yasuhiko; Iizuka, Hideo; Mizuno, Shintaro; Hasegawa, Kazuo; Ichikawa, Tadashi; Ito, Hiroshi; Kajino, Tsutomu; Ichiki, Akihisa; Motohiro, Tomoyoshi

    2014-09-01

    We have theoretically demonstrated a new light-trapping mechanism to reduce emission from a photovoltaic (PV) cell used for a monochromatic light source, which improves limiting conversion efficiency determined by the detailed balance. A multilayered bandpass filter formed on the surface of a PV cell has been found to prevent the light generated inside by radiative recombination from escaping the cell, resulting in a remarkable decrease of the effective solid angle for the emission. We have clarified a guide to design a suitable configuration of the bandpass filter and achieved significant reduction of the emission. The resultant gain in monochromatic conversion efficiency in the radiative limit due to the optimally designed 18-layerd bandpass filters is as high as 6% under normally incident 1064 nm illumination of 10 mW/cm2 ˜ 1 kW/cm2, compared with the efficiency for the perfect anti-reflection treatment to the surface of a conventional solar cell.

  5. Photovoltaic Cells involving Nonconjugated Conductive Polymer, Iodine-doped cis-Polyisoprene (Natural Rubber)

    NASA Astrophysics Data System (ADS)

    Jaju, S.; Thakur, M.

    2014-03-01

    Photovoltaic cells have been fabricated using titanium dioxide/doped cis-polyisoprene/carbon on ITO glass-substrates. Photocurrents and photo-voltages for different intensities of light (from a white light bulb, emission at 300-700 nm) have been measured. Use of the iodine-doped nonconjugated conductive polymer film (absorption ~ 250 to 700 nm) has led to significant enhancement of photocurrent compared to previous reports which included undoped polymer in a different cell-structure. A maximum photocurrent of about 0.20 mA was observed for a light intensity of ~ 5 mW/cm2. The maximum photo-voltage as observed was about 0.70 V for the same light intensity. Natural rubber being inexpensive these cells may provide cheaper alternatives to other reported cell structures.

  6. Photovoltaic properties of sintered CdS/CdTe solar cells doped with Cu

    NASA Astrophysics Data System (ADS)

    Park, J. W.; Ahn, B. T.; Im, H. B.; Kim, C. S.

    1992-11-01

    The effect of Cu doping before sintering on the photovoltaic properties of sintered CdS/CdTe solar cells were investigated by putting various amounts of CuCl2 either into the CdTe layer or into the back contact carbon layer. It was found that, as the amount of CuCl2 in the CdTe layers increased up to 25 ppm, the cell parameters of the sintered CdS/CdTe solar cells remained at about the same values, and then decreased sharply with further increase of CuCl2. The decreases in cell parameters are caused mainly by the increase in the resistivity of CdS and CdTe layer and the decrease in the optical transmission of CdS due to Cu doping from the CdTe.

  7. Light trapping for emission from a photovoltaic cell under normally incident monochromatic illumination

    SciTech Connect

    Takeda, Yasuhiko Iizuka, Hideo; Mizuno, Shintaro; Hasegawa, Kazuo; Ichikawa, Tadashi; Ito, Hiroshi; Kajino, Tsutomu; Ichiki, Akihisa; Motohiro, Tomoyoshi

    2014-09-28

    We have theoretically demonstrated a new light-trapping mechanism to reduce emission from a photovoltaic (PV) cell used for a monochromatic light source, which improves limiting conversion efficiency determined by the detailed balance. A multilayered bandpass filter formed on the surface of a PV cell has been found to prevent the light generated inside by radiative recombination from escaping the cell, resulting in a remarkable decrease of the effective solid angle for the emission. We have clarified a guide to design a suitable configuration of the bandpass filter and achieved significant reduction of the emission. The resultant gain in monochromatic conversion efficiency in the radiative limit due to the optimally designed 18-layerd bandpass filters is as high as 6% under normally incident 1064 nm illumination of 10 mW/cm²~ 1 kW/cm², compared with the efficiency for the perfect anti-reflection treatment to the surface of a conventional solar cell.

  8. A generic concept to overcome bandgap limitations for designing highly efficient multi-junction photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Guo, Fei; Li, Ning; Fecher, Frank W.; Gasparini, Nicola; Quiroz, Cesar Omar Ramirez; Bronnbauer, Carina; Hou, Yi; Radmilović, Vuk V.; Radmilović, Velimir R.; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J.

    2015-07-01

    The multi-junction concept is the most relevant approach to overcome the Shockley-Queisser limit for single-junction photovoltaic cells. The record efficiencies of several types of solar technologies are held by series-connected tandem configurations. However, the stringent current-matching criterion presents primarily a material challenge and permanently requires developing and processing novel semiconductors with desired bandgaps and thicknesses. Here we report a generic concept to alleviate this limitation. By integrating series- and parallel-interconnections into a triple-junction configuration, we find significantly relaxed material selection and current-matching constraints. To illustrate the versatile applicability of the proposed triple-junction concept, organic and organic-inorganic hybrid triple-junction solar cells are constructed by printing methods. High fill factors up to 68% without resistive losses are achieved for both organic and hybrid triple-junction devices. Series/parallel triple-junction cells with organic, as well as perovskite-based subcells may become a key technology to further advance the efficiency roadmap of the existing photovoltaic technologies.

  9. A generic concept to overcome bandgap limitations for designing highly efficient multi-junction photovoltaic cells.

    PubMed

    Guo, Fei; Li, Ning; Fecher, Frank W; Gasparini, Nicola; Ramirez Quiroz, Cesar Omar; Bronnbauer, Carina; Hou, Yi; Radmilović, Vuk V; Radmilović, Velimir R; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J

    2015-07-16

    The multi-junction concept is the most relevant approach to overcome the Shockley-Queisser limit for single-junction photovoltaic cells. The record efficiencies of several types of solar technologies are held by series-connected tandem configurations. However, the stringent current-matching criterion presents primarily a material challenge and permanently requires developing and processing novel semiconductors with desired bandgaps and thicknesses. Here we report a generic concept to alleviate this limitation. By integrating series- and parallel-interconnections into a triple-junction configuration, we find significantly relaxed material selection and current-matching constraints. To illustrate the versatile applicability of the proposed triple-junction concept, organic and organic-inorganic hybrid triple-junction solar cells are constructed by printing methods. High fill factors up to 68% without resistive losses are achieved for both organic and hybrid triple-junction devices. Series/parallel triple-junction cells with organic, as well as perovskite-based subcells may become a key technology to further advance the efficiency roadmap of the existing photovoltaic technologies.

  10. A generic concept to overcome bandgap limitations for designing highly efficient multi-junction photovoltaic cells

    PubMed Central

    Guo, Fei; Li, Ning; Fecher, Frank W.; Gasparini, Nicola; Quiroz, Cesar Omar Ramirez; Bronnbauer, Carina; Hou, Yi; Radmilović, Vuk V.; Radmilović, Velimir R.; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J.

    2015-01-01

    The multi-junction concept is the most relevant approach to overcome the Shockley–Queisser limit for single-junction photovoltaic cells. The record efficiencies of several types of solar technologies are held by series-connected tandem configurations. However, the stringent current-matching criterion presents primarily a material challenge and permanently requires developing and processing novel semiconductors with desired bandgaps and thicknesses. Here we report a generic concept to alleviate this limitation. By integrating series- and parallel-interconnections into a triple-junction configuration, we find significantly relaxed material selection and current-matching constraints. To illustrate the versatile applicability of the proposed triple-junction concept, organic and organic-inorganic hybrid triple-junction solar cells are constructed by printing methods. High fill factors up to 68% without resistive losses are achieved for both organic and hybrid triple-junction devices. Series/parallel triple-junction cells with organic, as well as perovskite-based subcells may become a key technology to further advance the efficiency roadmap of the existing photovoltaic technologies. PMID:26177808

  11. Fullerene C{sub 70} as a p-type donor in organic photovoltaic cells

    SciTech Connect

    Zhuang, Taojun; Wang, Xiao-Feng E-mail: zrhong@ucla.edu Sano, Takeshi; Kido, Junji E-mail: zrhong@ucla.edu; Hong, Ziruo E-mail: zrhong@ucla.edu; Li, Gang; Yang, Yang

    2014-09-01

    Fullerenes and their derivatives have been widely used as n-type materials in organic transistor and photovoltaic devices. Though it is believed that they shall be ambipolar in nature, there have been few direct experimental proofs for that. In this work, fullerene C{sub 70}, known as an efficient acceptor, has been employed as a p-type electron donor in conjunction with 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile as an electron acceptor in planar-heterojunction (PHJ) organic photovoltaic (OPV) cells. High fill factors (FFs) of more than 0.70 were reliably achieved with the C{sub 70} layer even up to 100 nm thick in PHJ cells, suggesting the superior potential of fullerene C{sub 70} as the p-type donor in comparison to other conventional donor materials. The optimal efficiency of these unconventional PHJ cells was 2.83% with a short-circuit current of 5.33 mA/cm{sup 2}, an open circuit voltage of 0.72 V, and a FF of 0.74. The results in this work unveil the potential of fullerene materials as donors in OPV devices, and provide alternative approaches towards future OPV applications.

  12. External quantum efficiency and photovoltaic performance of silicon cells deposited with aluminum, indium, and silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Ho, Wen-Jeng; Hu, Chia-Hua; Yeh, Chien-Wu; Lee, Yi-Yu

    2016-08-01

    In this study, the plasmonic light scattering of aluminum (Al), indium (In), and sliver (Ag) nanoparticles (NPs) deposited on silicon solar cells was demonstrated. For comparison, the dimensions of all NPs were maintained at 17-25 nm with a coverage of approximately 30-40% through the control of film deposition and thermal annealing conditions. Absorbance and surface plasmon Raman scattering were used to examine the different localized surface plasmon resonances (LSPRs) of the proposed NPs. Optical reflectance, external quantum efficiency (EQE) response, and photovoltaic current density-voltage characteristics under AM 1.5G illumination were used to confirm the contribution of the plasmonic light scattering of the NPs. The conversion efficiencies of the solar cells with Al, In, and Ag NPs increased 1.21-, 1.23-, and 1.17-fold, respectively, compared with that of the reference bare Si solar cell. The EQE response and photovoltaic performance revealed that Al and In NPs produced broadband plasmonic light scattering and increased efficiency, far exceeding the results obtained using Ag NPs.

  13. Analytical study of pulsed laser irradiation on some materials used for photovoltaic cells on satellites

    NASA Astrophysics Data System (ADS)

    Abd El-Hameed, Afaf M.

    2015-12-01

    The present research concerns on the study of laser-powered solar panels used for space applications. A mathematical model representing the laser effects on semiconductors has been developed. The temperature behavior and heat flow on the surface and through a slab has been studied after exposed to nano-second pulsed laser. The model is applied on two different types of common active semiconductor materials that used for photovoltaic cells fabrication as silicon (Si), and gallium arsenide (GaAs). These materials are used for receivers' manufacture for laser beamed power in space. Various values of time are estimated to clarify the heat flow through the material sample and generated under the effects of pulsed laser irradiation. These effects are theoretically studied in order to determine the performance limits of the solar cells when they are powered by laser radiation during the satellite eclipse. Moreover, the obtained results are carried out to optimize conversion efficiency of photovoltaic cells and may be helpful to give more explanation for layout of the light-electricity space systems.

  14. Photovoltaic technology assessment

    SciTech Connect

    Backus, C.E.

    1981-01-01

    After a brief review of the history of photovoltaic devices and a discussion of the cost goals set for photovoltaic modules, the status of photovoltaic technology is assessed. Included are discussions of: current applications, present industrial production, low-cost silicon production techniques, energy payback periods for solar cells, advanced materials research and development, concentrator systems, balance-of-system components. Also discussed are some nontechnical aspects, including foreign markets, US government program approach, and industry attitudes and approaches. (LEW)

  15. Photovoltaic surfaces enable clonal myoblastic cell release using visible light as external stimulation.

    PubMed

    Bhuyan, Mohammod Kabir; Rodriguez-Devora, Jorge; Tseng, Tzu-Liang Bill; Boland, Thomas

    2016-03-01

    Many new biomedical approaches to treating disease require the supply of cells delivered to an injured or diseased organ either individually, collectively as aggregates or sheets, or encapsulated with a scaffold. The collection of cells is accomplished by using enzymatic digestion witch suffer from the need to remove the enzymes after digestion. In addition, enzymatic methods are not applicable for all cells, cell aggregates, cell sheets or 3D structures. The objective of this study was to investigate the release of cultured cells from silicon based Photovoltaic (PV) surfaces using a light source as external stimulation. C2C12 myoblasts were cultured on the negative surface of a PV device and upon confluence they were exposed to light. The amount of released cells was quantified as a function light exposure. It was found that light exposure at 25,000 lux for one hour caused equivalent cell release from the PV surface than trypsination. The released cells are viable and can be re-cultured if needed. This mechanism may offer an alternative method to release excitable cells without using an enzymatic agent. This may be important for cell therapy if larger cell structures such as sheets need to be collected.

  16. US photovoltaic patents, 1951--1987

    SciTech Connect

    Not Available

    1988-09-01

    This document contains 2195 US patents on terrestrial photovoltaic (PV) power applications, including systems, components, and materials as well as manufacturing and support functions. The patent entries in this document were issued from 1951 through 1987; no patents were found in 1950. The entries were located by searching USPA, the data base of the US Patent Office. The final search retrieved all patents under the class ''Batteries, Thermoelectric and Photoelectric,'' and the subclasses ''Photoelectric,'' ''Testing,'' and ''Applications.'' The search also located patents that contained the words ''photovoltaic(s)'' or ''solar cell(s)'' and their derivatives. A manual search of the patents in the Solar Energy Research Institute (SERI) patent file augmented the data base search. After the initial list was compiled, most of the patents on the following subjects were excluded: space photovoltaic technology, use of the photovoltaic effect for detectors, and subjects only peripherally concerned with photovoltaics. Some patents on these three subjects were included when it appeared that those inventions might be of use in terrestrial PV power technologies.

  17. US Photovoltaic Patents, 1988--1990

    SciTech Connect

    Not Available

    1991-12-01

    This document contains US patents on terrestrial photovoltaic (PV) power applications, including systems, components, and materials, as well as manufacturing and support functions. The patent entries in this document were issued from 1988 through 1990. The entries were located by searching USPA, the data base of the US Patent Office. The final search retrieved all patents under the class ``Batteries, Thermoelectric and Photoelectric`` and the subclasses ``Photoelectric,`` ``Testing,`` and ``Applications.`` The search also located patents that contained the words ``photovoltaic(s)`` or ``solar cell(s)`` and their derivatives. A manual search of the patents in the Solar Energy Research Institute (SERI) patent file augmented the data base search. After the initial list was compiled, most of the patents on the following subjects were excluded: space photovoltaic technology, use of the photovoltaic effect for detectors and subjects only peripherally concerned with photovoltaics. Some patents on these three subjects were included when it appeared that those inventions might be of use in terrestrial PV power technologies.

  18. US Photovoltaic Patents, 1988--1990

    SciTech Connect

    Not Available

    1991-12-01

    This document contains US patents on terrestrial photovoltaic (PV) power applications, including systems, components, and materials, as well as manufacturing and support functions. The patent entries in this document were issued from 1988 through 1990. The entries were located by searching USPA, the data base of the US Patent Office. The final search retrieved all patents under the class Batteries, Thermoelectric and Photoelectric'' and the subclasses Photoelectric,'' Testing,'' and Applications.'' The search also located patents that contained the words photovoltaic(s)'' or solar cell(s)'' and their derivatives. A manual search of the patents in the Solar Energy Research Institute (SERI) patent file augmented the data base search. After the initial list was compiled, most of the patents on the following subjects were excluded: space photovoltaic technology, use of the photovoltaic effect for detectors and subjects only peripherally concerned with photovoltaics. Some patents on these three subjects were included when it appeared that those inventions might be of use in terrestrial PV power technologies.

  19. Photovoltaic Manufacturing Technology (PVMaT) improvements for ENTECH`s concentrator module. Final technical report, 9 January 1991--14 April 1991

    SciTech Connect

    O`Neill, M.J.; McDanal, A.J.; Perry, J.L.; Jackson, M.C.; Walters, R.R.

    1991-11-01

    This final technical report documents ENTECH`s Phase 1 contract with Photovoltaic Manufacturing Technology (PVMaT) project. Under this project we prepared a detailed description of our current manufacturing process for making our unique linear Fresnel lens photovoltaic concentrator modules. In addition, we prepared a detailed description of an improved manufacturing process, which will simultaneously increase module production rates, enhance module quality, and substantially reduce module costs. We also identified potential problems in implementing the new manufacturing process, and we proposed solutions to these anticipated problems. Before discussing the key results of our program, however, we present a brief description of our unique photovoltaic technology. The key conclusion of our PVMAT Phase 1 study is that our module technology, without further breakthroughs, can realistically meet the near-term DOE goal of 12 cents/kWh levelized electricity cost, provided that we successfully implement the new manufacturing process at a production volume of at least 10 megawatts per year. The key recommendation from our Phase 1 study is to continue our PVMaT project into Phase 2A, which is directed toward the actual manufacturing technology development required for our new module production process. 15 refs.

  20. Theory of photovoltaic characteristics of semiconductor quantum dot solar cells

    SciTech Connect

    Wu, Yuchang; Asryan, Levon V.

    2016-08-28

    We develop a comprehensive rate equations model for semiconductor quantum dot solar cells (QDSCs). The model is based on the continuity equations with a proper account for quantum dots (QDs). A general analytical expression for the total current density is obtained, and the current-voltage characteristic is studied for several specific situations. The degradation in the open circuit voltage of the QDSC is shown to be due to strong spontaneous radiative recombination in QDs. Due to small absorption coefficient of the QD ensemble, the improvement in the short circuit current density is negligible if only one QD layer is used. If spontaneous radiative recombination would be suppressed in QDs, a QDSC with multiple QD layers would have significantly higher short circuit current density and power conversion efficiency than its conventional counterpart. The effects of photoexcitation of carriers from discrete-energy states in QDs to continuum-energy states are discussed. An extended model, which includes excited states in QDs, is also introduced.

  1. SunEdison Photovoltaic Grid Integration Evaluation: Cooperative Research and Development Final Report, CRADA Number CRD-08-302

    SciTech Connect

    Kroposki, B.

    2012-09-01

    Under this Agreement, NREL will work with SunEdison to monitor and analyze the performance of photovoltaic (PV) systems as they relate to grid integration. Initially this project will examine the performance of PV systems with respect to evaluating the benefits and impacts on the electric power grid.

  2. Photovoltaic power generation system free of bypass diodes

    SciTech Connect

    Lentine, Anthony L.; Okandan, Murat; Nielson, Gregory N.

    2015-07-28

    A photovoltaic power generation system that includes a solar panel that is free of bypass diodes is described herein. The solar panel includes a plurality of photovoltaic sub-modules, wherein at least two of photovoltaic sub-modules in the plurality of photovoltaic sub-modules are electrically connected in parallel. A photovoltaic sub-module includes a plurality of groups of electrically connected photovoltaic cells, wherein at least two of the groups are electrically connected in series. A photovoltaic group includes a plurality of strings of photovoltaic cells, wherein a string of photovoltaic cells comprises a plurality of photovoltaic cells electrically connected in series. The strings of photovoltaic cells are electrically connected in parallel, and the photovoltaic cells are microsystem-enabled photovoltaic cells.

  3. Photovoltaic characteristics of n(+)pp(+) InP solar cells grown by OMVPE

    NASA Technical Reports Server (NTRS)

    Tyagi, S.; Singh, K.; Bhimnathwala, H.; Ghandhi, S. K.; Borrego, J. M.

    1990-01-01

    The photovoltaic characteristics of n(+)/p/p(+) homojunction InP solar cells fabricated by organometallic vapor-phase epitaxy (OMVPE) are described. The cells are characterized by I-V, C-V and quantum efficiency measurements, and simulations are used to obtain various device and material parameters. The I-V characteristics show a high recombination rate in the depletion region; this is shown to be independent of the impurity used. It is shown that cadmium is easier to use as an acceptor for the p base and p(+) buffer and is therefore beneficial. The high quantum efficiency of 98 percent at long wavelengths measured in these cells indicates a very good collection efficiency in the base. The short-wavelength quantum efficiency is poor, indicating a high surface recombination.

  4. Electrochemical photovoltaic and photoelectrochemical storage cells based on II-VI polycrystalline thin film materials

    SciTech Connect

    Wallace, W.L.

    1983-06-01

    Research on electrochemical photovoltaic cells incorporating thin film CdSe and CdSe /SUB x/ Te /SUB 1-x/ photoanodes has progressed to the point where efficiencies of up to 7% can be achieved on small area electrodes using a polysulfide electrolyte. Higher efficiencies can be obtained in alternate electrolytes in significantly less stable systems. The major limitations on cell efficiency are associated with the open circuit voltage and fill factor. At present, the most promising photoelectrochemical storage system is an in situ three electrode cell which consists of an n-CdSe /SUB x/ Te /SUB 1-x/ photoanode and CoS counterelectrode in a sulfide/polysulfide electrolyte and a Sn/SnS storage electrode isolated in an aqueous sulfide electrolyte.

  5. Optimization of material/device parameters of CdTe photovoltaic for solar cells applications

    NASA Astrophysics Data System (ADS)

    Wijewarnasuriya, Priyalal S.

    2016-05-01

    Cadmium telluride (CdTe) has been recognized as a promising photovoltaic material for thin-film solar cell applications due to its near optimum bandgap of ~1.5 eV and high absorption coefficient. The energy gap is near optimum for a single-junction solar cell. The high absorption coefficient allows films as thin as 2.5 μm to absorb more than 98% of the above-bandgap radiation. Cells with efficiencies near 20% have been produced with poly-CdTe materials. This paper examines n/p heterostructure device architecture. The performance limitations related to doping concentrations, minority carrier lifetimes, absorber layer thickness, and surface recombination velocities at the back and front interfaces is assessed. Ultimately, the paper explores device architectures of poly- CdTe and crystalline CdTe to achieve performance comparable to gallium arsenide (GaAs).

  6. Polymer photovoltaic cell embedded with p-type single walled carbon nanotubes fabricated by spray process.

    PubMed

    Kim, Dal-Ho; Park, Jea-Gun

    2012-08-17

    In the current study, we fabricated polymer (poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C(61) butyric-acid methyl-ester (PCBM) blend) photovoltaic (PV) cells embedded with p-type single walled carbon nanotubes (SWCNTs) with tangled hair morphology. The power conversion efficiency (PCE) rapidly increased with SWCNT concentration of up to 6.83% coverage, and then decreased and saturated with increasing SWCNT concentration; i.e., the PCE peaks at 5.379%. This tendency is mainly associated with hole transport efficiency toward the transparent electrode (indium-tin-oxide (ITO)) via SWCNTs, directly determining the series resistance and shunt resistance of the polymer PV cells embedded with SWCNTs: the PV cell is increasing shunt resistance and decreasing series resistance.

  7. Efficiency enhancement in two-cell CIGS photovoltaic system with low-cost optical spectral splitter.

    PubMed

    Maragliano, Carlo; Apostoleris, Harry; Bronzoni, Matteo; Rampino, Stefano; Stefancich, Marco; Chiesa, Matteo

    2016-01-25

    Spectrum splitting represents a valid alternative to multi-junction solar cells for broadband light-to-electricity conversion. While this concept has existed for decades, its adoption at the industrial scale is still stifled by high manufacturing costs and inability to scale to large areas. Here we report the experimental validation of a novel design that could allow the widespread adoption of spectrum splitting as a low-cost approach to high efficiency photovoltaic conversion. Our system consists of a prismatic lens that can be manufactured using the same methods employed for conventional CPV optic production, and two inexpensive CuInGaSe(2) (CIGS) solar cells having different composition and, thus, band gaps. We demonstrate a large improvement in cell efficiency under the splitter and show how this can lead to substantial increases in system output at competitive cost using existing technologies.

  8. Graphene-based photovoltaic cells for near-field thermal energy conversion.

    PubMed

    Messina, Riccardo; Ben-Abdallah, Philippe

    2013-01-01

    Thermophotovoltaic devices are energy-conversion systems generating an electric current from the thermal photons radiated by a hot body. While their efficiency is limited in far field by the Schockley-Queisser limit, in near field the heat flux transferred to a photovoltaic cell can be largely enhanced because of the contribution of evanescent photons, in particular for a source supporting a surface mode. Unfortunately, in the infrared where these systems operate, the mismatch between the surface-mode frequency and the semiconductor gap reduces drastically the potential of this technology. In this paper we propose a modified thermophotovoltaic device in which the cell is covered by a graphene sheet. By discussing the transmission coefficient and the spectral properties of the flux, we show that both the cell efficiency and the produced current can be enhanced, paving the way to promising developments for the production of electricity from waste heat.

  9. Organic Photovoltaic Cells with Improved Performance Using Bathophenanthroline as a Buffer Layer

    NASA Astrophysics Data System (ADS)

    Wang, Na-na; Yu, Jun-sheng; Lin, Hui; Jiang, Ya-dong

    2010-02-01

    The role of bathophenanthroline (Bphen) as a buffer layer inserted between fullerene (C60) and Ag cathode in organic photovoltaic (OPV) cell was discussed. By introducing Bphen as a buffer layer with thicknes from 0 to 2.5 nm, the power conversion efficiency of the OPV cell based on copper phthalocyanine (CuPc) and C60 was increased from 0.87% to 2.25% under AM 1.5 solar illumination at an intensity of 100 mW/cm2, which was higher than that of bathocuproine used as a buffer layer. The photocurrent-voltage characteristics showed that Bphen effectively improves electron transport through C60 layer into Ag electrode and leads to balance charge carrier transport capability. The influence of Bphen thickness on OPV cells was also investigated. Furthermore, the absorption spectrum shows that an additional Bphen layer enhances the light harvest capability of CuPc/C60.

  10. Copper thiocyanate: An attractive hole transport/extraction layer for use in organic photovoltaic cells

    SciTech Connect

    Treat, Neil D. E-mail: t.anthopoulos@imperial.ac.uk; Stingelin, Natalie; Yaacobi-Gross, Nir; Faber, Hendrik; Perumal, Ajay K.; Bradley, Donal D. C.; Anthopoulos, Thomas D. E-mail: t.anthopoulos@imperial.ac.uk

    2015-07-06

    We report the advantageous properties of the inorganic molecular semiconductor copper(I) thiocyanate (CuSCN) for use as a hole collection/transport layer (HTL) in organic photovoltaic (OPV) cells. CuSCN possesses desirable HTL energy levels [i.e., valence band at −5.35 eV, 0.35 eV deeper than poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS)], which produces a 17% increase in power conversion efficiency (PCE) relative to PEDOT:PSS-based devices. In addition, a two-fold increase in shunt resistance for the solar cells measured in dark conditions is achieved. Ultimately, CuSCN enables polymer:fullerene based OPV cells to achieve PCE > 8%. CuSCN continues to offer promise as a chemically stable and straightforward replacement for the commonly used PEDOT:PSS.

  11. Electricity from photovoltaic solar cells. Flat-Plate Solar Array Project of the US Department of Energy's National Photovoltaics Program: 10 years of progress

    NASA Technical Reports Server (NTRS)

    Christensen, Elmer

    1985-01-01

    The objectives were to develop the flat-plate photovoltaic (PV) array technologies required for large-scale terrestrial use late in the 1980s and in the 1990s; advance crystalline silicon PV technologies; develop the technologies required to convert thin-film PV research results into viable module and array technology; and to stimulate transfer of knowledge of advanced PV materials, solar cells, modules, and arrays to the PV community. Progress reached on attaining these goals, along with future recommendations are discussed.

  12. Inverted Metamorphic Cell Development: Cooperative Research and Development Final Report, CRADA Number CRD-05-156

    SciTech Connect

    Wanlass, M.

    2012-05-01

    This CRADA targeted technology transfer of the inverted metamorphic multi-junction (IMM) solar cell innovation from NREL to Emcore Photovoltaics. The technology transfer was successfully completed. Additionally, NREL provided materials characterization of solar cell structures produced at Emcore.

  13. Optimizing the electrical properties of PEDOT:PSS films by co-solvents and their application in polymer photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Pathak, C. S.; Singh, J. P.; Singh, R.

    2017-09-01

    A simple optimizing approach that improves the electrical properties of poly (3,4-ethylenedioxylthiophene):poly(styrenesulfonate) (PEDOT:PSS) films and their application in heterojunction diodes and polymer photovoltaic cells is presented in this paper. The optimizing process is performed by mixing the organic solvents n-methyl-2-pyrrolidone and methanol along with dimethyl sulfoxide into PEDOT:PSS solution achieving the facile combination of the solvent effect. Electrical conductivity varies from 0.16 to 194 S/cm by variation in the concentration of n-methyl-2-pyrrolidone. It is shown that the enhancement in conductivity of PEDOT:PSS films with co-solvents by three orders of magnitude is achieved compared to pristine PEDOT:PSS with transparency >92% in the visible region. The heterojunction diodes fabricated with co-solvents studied in this work showed rectifying behavior, and polymer photovoltaic cells fabricated with the co-solvents exhibited photovoltaic performance.

  14. Enhanced photovoltaic performances of graphene/Si solar cells by insertion of a MoS₂ thin film.

    PubMed

    Tsuboi, Yuka; Wang, Feijiu; Kozawa, Daichi; Funahashi, Kazuma; Mouri, Shinichiro; Miyauchi, Yuhei; Takenobu, Taishi; Matsuda, Kazunari

    2015-09-14

    Transition-metal dichalcogenides exhibit great potential as active materials in optoelectronic devices because of their characteristic band structure. Here, we demonstrated that the photovoltaic performances of graphene/Si Schottky junction solar cells were significantly improved by inserting a chemical vapor deposition (CVD)-grown, large MoS2 thin-film layer. This layer functions as an effective electron-blocking/hole-transporting layer. We also demonstrated that the photovoltaic properties are enhanced with the increasing number of graphene layers and the decreasing thickness of the MoS2 layer. A high photovoltaic conversion efficiency of 11.1% was achieved with the optimized trilayer-graphene/MoS2/n-Si solar cell.

  15. Inkjet Printed Metallizations for Cu(In1-xGax)Se2 Photovoltaic Cells

    SciTech Connect

    Hersh, P. A.; Curtis, C. J.; van Hest, M. F. A. M.; Kreuder, J. J.; Pasquarelli, R.; Miednaer, A.; Ginley, D. S.

    2011-12-01

    This study reports the inkjet printing of Ag front contacts on Aluminum doped Zinc Oxide (AZO)/intrinsic Zinc Oxide (i-ZnO)/CdS/Cu(In{sub 1-x}Ga{sub x})Se{sub 2} (CIGS)/Mo thin film photovoltaic cells. The printed Ag contacts are being developed to replace the currently employed evaporated Ni/Al bi-layer contacts. Inkjet deposition conditions were optimized to reduce line resistivity and reduce contact resistance to the Al:ZnO layer. Ag lines printed at a substrate temperature of 200 C showed a line resistivity of 2.06 {mu}{Omega} {center_dot} cm and a contact resistance to Al:ZnO of 8.2 {+-} 0.2 m{Omega} {center_dot} cm{sup 2} compared to 6.93 {+-} 0.3 m{Omega} {center_dot} cm{sup 2} for thermally evaporated contacts. These deposition conditions were used to deposit front contacts onto high quality CIGS thin film photovoltaic cells. The heating required to print the Ag contacts caused the performance to degrade compared to similar devices with evaporated Ni/Al contacts that were not heated. Devices with inkjet printed contacts showed 11.4% conversion efficiency compared to 14.8% with evaporated contacts. Strategies to minimize heating, which is detrimental for efficiency, during inkjet printing are proposed.

  16. Dependence of photocurrent generation on the crystalline phase of titanyl phthalocyanine film in heterojunction photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Jeon, Hyeon-Gu; Ito, Yosuke; Sunohara, Yoshimi; Ichikawa, Musubu

    2015-09-01

    We report that the photocurrent generation of a titanyl phthalocyanine (TiOPc) layer in heterojunction photovoltaic cells is strongly dependent on the crystalline phase of the TiOPc layer. Vacuum-deposited TiOPc films with an amorphous phase were changed into mixed crystalline films with two or three crystalline phases, Phase I and Phase II or Phase Y, by solvent vapor treatment with various solvents, which is confirmed from the ultraviolet-visible absorption spectra and X-ray diffraction patterns of solvent-vapor-treated TiOPc films. From the incident photon to current conversion efficiency (IPCE) measurement, it is clearly demonstrated that only the amorphous phase and Phase II but not Phase I nor Phase Y of TiOPc can contribute to photoelectric conversion in heterojunction photovoltaic cells. This result may come from the low charge generation (exciton dissociation) efficiency of Phase I and Phase Y crystalline structures, which was supported by the change in IPCE curves under inverse bias application.

  17. Tilted bulk heterojunction organic photovoltaic cells grown by oblique angle deposition

    NASA Astrophysics Data System (ADS)

    Li, Ning; Forrest, Stephen R.

    2009-09-01

    We demonstrate small molecule bulk heterojunction organic photovoltaic cells using oblique angle vacuum deposition. Obliquely deposited donor chloroaluminum phthalocyanine (ClAlPc) films on indium tin oxide have surface feature sizes of ˜30 nm, resulting in ClAlPc/C60 donor-acceptor heterojunctions (HJs) with approximately twice the interface area of HJs grown at normal incidence. This results in nearly twice the external quantum efficiency in the ClAlPc absorption band compared with analogous, planar HJs. The efficiency increase is attributed to the increased surface area presented by the donor-acceptor junction to the incident illumination by ClAlPc protrusions lying obliquely to the substrate plane formed during deposition. The power conversion efficiency improves from (2.0±0.1)% to (2.8±0.1)% under 1 sun, AM 1.5G simulated solar illumination. Similarly, the power efficiency of copper phthalocyanine/C60 organic photovoltaic cells is increased from (1.3±0.1)% to (1.7±0.1)%.

  18. InGaN-based thin film solar cells: Epitaxy, structural design, and photovoltaic properties

    SciTech Connect

    Sang, Liwen; Liao, Meiyong; Koide, Yasuo; Sumiya, Masatomo

    2015-03-14

    In{sub x}Ga{sub 1−x}N, with the tunable direct bandgaps from ultraviolet to near infrared region, offers a promising candidate for the high-efficiency next-generation thin-film photovoltaic applications. Although the adoption of thick InGaN film as the active region is desirable to obtain efficient light absorption and carrier collection compared to InGaN/GaN quantum wells structure, the understanding on the effect from structural design is still unclear due to the poor-quality InGaN films with thickness and difficulty of p-type doping. In this paper, we comprehensively investigate the effects from film epitaxy, doping, and device structural design on the performances of the InGaN-based solar cells. The high-quality InGaN thick film is obtained on AlN/sapphire template, and p-In{sub 0.08}Ga{sub 0.92}N is achieved with a high hole concentration of more than 10{sup 18 }cm{sup −3}. The dependence of the photovoltaic performances on different structures, such as active regions and p-type regions is analyzed with respect to the carrier transport mechanism in the dark and under illumination. The strategy of improving the p-i interface by using a super-thin AlN interlayer is provided, which successfully enhances the performance of the solar cells.

  19. Hybrid photovoltaic junctions: metal/molecular organic insulator/semiconductor MOIS solar cells

    NASA Astrophysics Data System (ADS)

    Har-Lavan, Rotem; Ron, Izhar; Thieblemont, Florent; Cahen, David

    2008-04-01

    Using a dense organic monolayer, self-assembled and directly bound to n-Si, as high quality insulator with a thickness that can be varied from 1.5-2.5 nm, we construct a Metal-Organic Insulator-Semiconductor (MOIS) structure, which, if fabricated with semi-transparent top electrode, performs as a hybrid organic-inorganic photovoltaic device. The feasibility of the concept and the electrical properties of the insulating layer were first shown with a Hg top electrode, allowing use of prior know-how from electron transport through molecular monolayers, but with photon collection only from around the electrode. We then used another bottom-up fabrication technique, in addition to molecular self-assembly, electro-less metal deposition, to implement an all-covalently bound solid state device. Electro-less Au deposition yields an electrically continuous, porous and semi-transparent top electrode, improving photon harvesting. Aside from being a nearly ideal insulator, the monolayer acts to passivate and protect the interfacial Si layer from defects and to decrease the surface state density. In addition the cell, like any MIS solar cell, benefits from that the light needs only to cross a few thin transparent layers (anti-reflective coating, organic insulator) to reach the photovoltaically active cell part. This helps to generate carriers close to the junction area, even by short wavelength photons, and, thus, to increase light collection, compared to p-n junction solar cells. Due to low temperature cell fabrication without high vacuum steps, the MOIS approach might be interesting for low cost solar cells.

  20. Final Technical Progress Report: High-Efficiency Low-Cost Thin-Film GaAs Photovoltaic Module Development Program; July 14, 2010 - January 13, 2012

    SciTech Connect

    Mattos, L.

    2012-03-01

    This is the final technical progress report of the High-Efficiency Low-Cost Thin-Film GaAs Photovoltaic Module Development Program. Alta Devices has successfully completed all milestones and deliverables established as part of the NREL PV incubator program. During the 18 months of this program, Alta has proven all key processes required to commercialize its solar module product. The incubator focus was on back end process steps directed at conversion of Alta's high quality solar film into high efficiency 1-sun PV modules. This report describes all program deliverables and the work behind each accomplishment.

  1. Development of New Absorber Materials to Achieve Organic Photovoltaic Commercial Modules with 15% Efficiency and 20 Years Lifetime: Cooperative Research and Development Final Report, CRADA Number CRD-12-498

    SciTech Connect

    Olson, D.

    2014-08-01

    Under this CRADA the parties will develop intermediates or materials that can be employed as the active layer in dye sensitized solar cells printed polymer systems, or small molecule organic photovoltaics.

  2. Enhancing photovoltaic efficiency through radiative cooling of solar cells below ambient temperature

    NASA Astrophysics Data System (ADS)

    Safi, Taqiyyah; Munday, Jeremy

    Sunlight heats up solar cells and the resulting elevated solar cell temperature adversely effects the photovoltaic efficiency and the reliability of the cell. Currently, a variety of active and passive cooling strategies are used to lower the operating temperature of the solar cell. Passive radiative cooling requires no energy input, and is ideal for solar cells; however, previously demonstrated devices still operate above the ambient, leading to a lower efficiency as compared to the ideal Shockley-Queisser limit, which is defined for a cell in contact with an ideal heat sink at ambient temperature (300 K). In this talk, we will describe the use of radiative cooling techniques to lower the cell temperature below the ambient temperature. We show that by combining specifically designed radiative cooling structures with solar cells, efficiencies higher than the limiting efficiency achievable at 300 K can be obtained for solar cells in both terrestrial and extraterrestrial environments. We show that these structures yield an efficiency 0.87% higher than a typical PV module at operating temperatures in a terrestrial application. We also demonstrate an efficiency advantage of 0.4-2.6% for cells in an extraterrestrial environment in near-earth orbit.

  3. Photovoltaic development in Argentina

    SciTech Connect

    Godfrin, E.M.; Duran, J.C.; Frigerio, A.; Moragues, J.A.

    1994-12-31

    A critical assessment of the photovoltaic program in Argentina is presented. Research and development activities on photovoltaic cells as well as industrial and technological development are still in the initial stages. Activities accomplished by the Atomic Energy Commission (CNEA) and the Institute of Technology Development for the Chemical industry (INTEC) are briefly described. The evolution of photovoltaic installations in Argentina is analyzed and accumulative data up to 1993 are given. A summary of the potential market for photovoltaic systems in the short and medium term is presented.

  4. Influence of dislocations on photovoltaic properties of multicrystalline silicon solar cells

    NASA Astrophysics Data System (ADS)

    El Ghitani, H.; Pasquinelli, M.; Martinuzzi, S.

    1993-10-01

    The photovoltaic properties of large grained polycrystalline silicon solar cells are mainly affected by the presence of dislocations. Both the recombination of carriers at dislocation (which degrades the photocurrent) and the transport of carriers along the dislocation cores crossing the junction (which increases the dark current) are taken into account. The influence of the density N_dis and recombination activity S_d of dislocations on the short circuit current density J_sc, open circuit voltage V_oc, fill factor FF, and efficiency η are computed. The computed values are compared to experimental results. Les propriétés photovoltaïques des cellules solaires au silicium multicristallin à gros grains, sont principalement affectées par la présence de dislocations. Nous nous intéressons plus particulièrement à la recombinaison des porteurs de charges aux dislocations qui affecte en premier lieu le photocourant et au transport des charges le long du cœur des dislocations traversant la jonction et qui est responsable de l'augmentation du courant d'obscurité. Nous avons modélisé l'influence de la densité de dislocations N_dis et de leur activité recombinante S_d sur les principaux paramètres photovoltaïques (le courant de court-circuit J_sc, la tension de circuit ouvert V_oc, le facteur de forme FF, et le rendement η). Le modèle est ensuite confronté aux résultats expérimentaux.

  5. Multichannel Spectroscopic Ellipsometry for CdTe Photovoltaics: from Materials and Interfaces to Solar Cells

    NASA Astrophysics Data System (ADS)

    Koirala, Prakash

    growth. Information from RT-SE at a single point during solar cell stack deposition assists in the development of a model that has been used for mapping the properties of the completed cell stack, which can then be correlated with device performance. Independent non-uniformities in the layers over the full area of the cell stack enable optimization of cell performance combinatorially. The polycrystalline CdS/CdTe thin-film solar cell in the superstrate configuration has been studied by SE using glass side illumination whereby the single reflection from the glass/film-stack interface is collected whereas that from the ambient/glass interface and those from multiple glass/film-stack reflections are rejected. The SE data analysis applies an optical model consisting of a multilayer stack with bulk and interface layers. The dielectric functions epsilonfor the solar cell component materials were obtained by variable-angle and in-situ SE. Variability in the properties of the materials are introduced through free parameters in analytical expressions for the dielectric functions. In the SE analysis of the complete cell, a step-wise procedure ranks all free parameters of the model, including thicknesses and those defining the spectra in epsilon, according to their ability to reduce the root-mean-square deviation between simulated and measured SE spectra. The results for the best fit thicknesses compare well with electron microscopy. From the optical model, including all best-fit parameters, the solar cell quantum efficiency (QE) can be simulated without free parameters, and comparisons with QE measurements have enabled the identification of losses. The capabilities have wide applications in off-line photovoltaic module mapping and in-line monitoring of coated glass at intermediate stages of production. Mapping spectroscopic ellipsometry (M-SE) has been applied in this dissertation research as an optimization procedure for polycrystalline CdS/CdTe solar cell fabrication on TCO

  6. Efficient electroluminescent cooling with a light-emitting diode coupled to a photovoltaic cell (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Xiao, Tianyao P.; Chen, Kaifeng; Santhanam, Parthiban; Fan, Shanhui; Yablonovitch, Eli

    2017-02-01

    The new breakthrough in photovoltaics, exemplified by the slogan "A great solar cell has to be a great light-emitting diode (LED)", has led to all the major new solar cell records, while also leading to extraordinary LED efficiency. As an LED becomes very efficient in converting its electrical input into light, the device cools as it operates because the photons carry away entropy as well as energy. If these photons are absorbed in a photovoltaic (PV) cell, the generated electricity can be used to provide part of the electrical input that drives the LED. Indeed, the LED/PV cell combination forms a new type of heat engine with light as the working fluid. The electroluminescent refrigerator requires only a small amount of external electricity to provide cooling, leading to a high coefficient of performance. We present the theoretical performance of such a refrigerator, in which the cool side (LED) is radiatively coupled to the hot side (PV) across a vacuum gap. The coefficient of performance is maximized by using a highly luminescent material, such as GaAs, together with device structures that optimize extraction of the luminescence. We consider both a macroscopic vacuum gap and a sub-wavelength gap; the latter allows for evanescent coupling of photons between the devices, potentially providing a further enhancement to the efficiency of light extraction. Using device assumptions based on the current record-efficiency solar cells, we show that electroluminescent cooling can, in certain regimes of cooling power, achieve a higher coefficient of performance than thermoelectric cooling.

  7. Aluminium alloyed iron-silicide/silicon solar cells: A simple approach for low cost environmental-friendly photovoltaic technology.

    PubMed

    Kumar Dalapati, Goutam; Masudy-Panah, Saeid; Kumar, Avishek; Cheh Tan, Cheng; Ru Tan, Hui; Chi, Dongzhi

    2015-12-03

    This work demonstrates the fabrication of silicide/silicon based solar cell towards the development of low cost and environmental friendly photovoltaic technology. A heterostructure solar cells using metallic alpha phase (α-phase) aluminum alloyed iron silicide (FeSi(Al)) on n-type silicon is fabricated with an efficiency of 0.8%. The fabricated device has an open circuit voltage and fill-factor of 240 mV and 60%, respectively. Performance of the device was improved by about 7 fold to 5.1% through the interface engineering. The α-phase FeSi(Al)/silicon solar cell devices have promising photovoltaic characteristic with an open circuit voltage, short-circuit current and a fill factor (FF) of 425 mV, 18.5 mA/cm(2), and 64%, respectively. The significant improvement of α-phase FeSi(Al)/n-Si solar cells is due to the formation p(+-)n homojunction through the formation of re-grown crystalline silicon layer (~5-10 nm) at the silicide/silicon interface. Thickness of the regrown silicon layer is crucial for the silicide/silicon based photovoltaic devices. Performance of the α-FeSi(Al)/n-Si solar cells significantly depends on the thickness of α-FeSi(Al) layer and process temperature during the device fabrication. This study will open up new opportunities for the Si based photovoltaic technology using a simple, sustainable, and los cost method.

  8. Laser generated nanoparticles based photovoltaics.

    PubMed

    Petridis, C; Savva, K; Kymakis, E; Stratakis, E

    2017-03-01

    The exploitation of nanoparticles (NP), synthesized via laser ablation in liquids, in photovoltaic devices is reviewed. In particular, the impact of NPs' incorporation into various building blocks within the solar cell architecture on the photovoltaic performance and stability is presented and analysed for the current state of the art photovoltaic technologies.

  9. Microsystems Enabled Photovoltaics

    ScienceCinema

    Gupta, Vipin; Nielson, Greg; Okandan, Murat, Granata, Jennifer; Nelson, Jeff; Haney, Mike; Cruz-Campa, Jose Luiz

    2016-07-12

    Sandia's microsystems enabled photovoltaic advances combine mature technology and tools currently used in microsystem production with groundbreaking advances in photovoltaics cell design, decreasing production and system costs while improving energy conversion efficiency. The technology has potential applications in buildings, houses, clothing, portable electronics, vehicles, and other contoured structures.

  10. Microsystems Enabled Photovoltaics

    SciTech Connect

    Gupta, Vipin; Nielson, Greg; Okandan, Murat, Granata, Jennifer; Nelson, Jeff; Haney, Mike; Cruz-Campa, Jose Luiz

    2012-07-02

    Sandia's microsystems enabled photovoltaic advances combine mature technology and tools currently used in microsystem production with groundbreaking advances in photovoltaics cell design, decreasing production and system costs while improving energy conversion efficiency. The technology has potential applications in buildings, houses, clothing, portable electronics, vehicles, and other contoured structures.

  11. Al-doping effects on the photovoltaic performance of inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Yu, Xuan; Shi, Ya-feng; Yu, Xiao-ming; Zhang, Jian-jun; Ge, Ya-ming; Chen, Li-qiao; Pan, Hong-jun

    2016-03-01

    The properties of Al-doped ZnO (AZO) play an important role in the photovoltaic performance of inverted polymer solar cells (PSCs), which is used as electron transport and hole blocking buffer layers. In this work, we study the effects of Al-doping level in AZO on device performance in detail. Results indicate that the device performance intensely depends on the Al-doping level. The AZO thin films with Al-doping atomic percentage of 1.0% possess the best conductivity. The resulting solar cells show the enhanced short current density and the fill factor ( FF) simultaneously, and the power conversion efficiency ( PCE) is improved by 74%, which are attributed to the reduced carrier recombination and the optimized charge transport and extraction between AZO and the active layer.

  12. Light-Induced Space-Charge Accumulation Zone as Photovoltaic Mechanism in Perovskite Solar Cells.

    PubMed

    Zarazua, Isaac; Bisquert, Juan; Garcia-Belmonte, Germà

    2016-02-04

    We fabricated formamidinium lead iodide perovskite solar cell for analysis of the photovoltaic mechanism based on the interpretation of the capacitance variation under illumination. It was shown that the low-frequency capacitance increases proportional to incident light intensity, and in addition it increases proportional to absorber thickness. Furthermore, the voltage dependence of capacitance is exponential with slope 1/2 (thermal energy). We conclude that the large photovoltage and capacitance are associated with electronic accumulation zone at the interface with the metal oxide contact. While this type of accumulation capacitance is common in many devices as transistors, the perovskite solar cell shows a singular behavior in that under light the electronic carrier accumulation grows unlimited by another series capacitance, reaching values as large as 10 mF cm(-2) at one sun illumination.

  13. Fabrication and photovoltaic properties of ZnO nanorods/perovskite solar cells

    SciTech Connect

    Shirahata, Yasuhiro; Tanaike, Kohei; Akiyama, Tsuyoshi; Fujimoto, Kazuya; Suzuki, Atsushi; Balachandran, Jeyadevan; Oku, Takeo

    2016-02-01

    ZnO nanorods/perovskite solar cells with different lengths of ZnO nanorods were fabricated. The ZnO nanorods were prepared by chemical bath deposition and directly confirmed to be hexagon-shaped nanorods. The lengths of the ZnO nanorads were controlled by deposition condition of ZnO seed layer. Photovoltaic properties of the ZnO nanorods/CH{sub 3}NH{sub 3}PbI{sub 3} solar cells were investigated by measuring current density-voltage characteristics and incident photon to current conversion efficiency. The highest conversion efficiency was obtained in ZnO nanorods/CH{sub 3}NH{sub 3}PbI{sub 3} with the longest ZnO nanorods.

  14. Very-high-efficiency double-heterostructure copper phthalocyanine/C60 photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Peumans, P.; Forrest, S. R.

    2001-07-01

    We demonstrate an external power conversion efficiency of (3.6±0.2)% under AM1.5 spectral illumination of 150 mW/cm2 (1.5 suns) with vacuum-deposited copper phthalocyanine/C60 thin-film double-heterostructure photovoltaic cells incorporating an exciton-blocking layer (EBL). We show that the anode work function influences the photocarrier collection characteristics through the built-in electric field. The cell parameters are less sensitive to the cathode work function, which is attributed to cathode-induced defect states in the EBL energy gap. The presence of these defect states also explains the surprisingly low resistance of the EBL to electron transport. We anticipate significant further improvements in power conversion efficiency by employing optimal structures in light-trapping geometries.

  15. Smart photovoltaics based on dye-sensitized solar cells using photochromic spiropyran derivatives as photosensitizers

    SciTech Connect

    Ma, Shengbo; Ting, Hungkit; Ma, Yingzhuang; Zheng, Lingling; Zhang, Miwei; Xiao, Lixin E-mail: lxxiao@pku.edu.cn; Chen, Zhijian E-mail: lxxiao@pku.edu.cn

    2015-05-15

    In this paper, smart photovoltaic (SPV) devices, integrating both functions of solar cells and smart windows, was fabricated based on dye-sensitized solar cells using photochromic spiropyran derivatives SIBT as photosensitizers. SPV devices have self-regulated power conversion efficiency (PCE) and light transmission responding to the incident spectra due to the photoisomerization of SIBT. SIBT isomerize from closed-ring form to open-ring form under UV illumination, accompanied with enhanced visible light absorption and electron delocalization. Therefore, increased PCE and absorption in SPV devices were observed under UV treatment and the devices can be restored gradually to the initial status when kept in dark. The SPV devices have self-regulation of PCE and sunlight transmission responding to the changing sun spectra in different times of a day, providing a proper energy usage and a better sun-shading.

  16. Enhanced Photocurrent in a Photovoltaic Cell involving a Nonconjugated Conductive Polymer, Poly(β-pinene)

    NASA Astrophysics Data System (ADS)

    Sangal, M.; Telang, G.; Thakur, M.

    2013-03-01

    Photovoltaic cells have been fabricated using titanium dioxide/doped poly(β-pinene)/carbon on ITO glass-substrates. Photocurrents and photo-voltages for different intensities of light (from a white illuminant light bulb, emission at 300-700 nm) have been measured. Use of iodine-doped nonconjugated conductive polymer film has led to significant enhancement of photocurrent compared to previous reports which included a different cell structure with undoped polymer-C60 composites. A maximum photocurrent of about 0.3 mA was observed for a light intensity of about 5mW/cm2. The maximum photo-voltage as observed was about 0.6 V for the same light intensity.

  17. Broadband light trapping in thin organic photovoltaic cells using plasmonic resonant antennas

    NASA Astrophysics Data System (ADS)

    Le, Khai Q.

    2013-08-01

    A numerical investigation of plasmonic resonant antennas influence on optical absorption efficiency of organic photovoltaic (PV) cells with thin active layers is reported. Integrating cylindrical Ag antennas on PV cells can enhance absorption efficiency by up to 22%, over a broad bandwidth of operation. This corresponds to an increase in integrated AM1.5G absorption at normal incidence from 48 to 58.5%. Broadband enhancement is observed for transverse-electric and transverse-magnetic polarized incident light, over a wide angle range. It is attributed to plasmonic antennas converting incident sunlight to surface plasmon resonant modes, localized around the antenna/polymer active layer interface. This results in a strong field enhancement in the active layer and enhances absorption efficiency.

  18. Smart photovoltaics based on dye-sensitized solar cells using photochromic spiropyran derivatives as photosensitizers

    NASA Astrophysics Data System (ADS)

    Ma, Shengbo; Ting, Hungkit; Ma, Yingzhuang; Zheng, Lingling; Zhang, Miwei; Xiao, Lixin; Chen, Zhijian

    2015-05-01

    In this paper, smart photovoltaic (SPV) devices, integrating both functions of solar cells and smart windows, was fabricated based on dye-sensitized solar cells using photochromic spiropyran derivatives SIBT as photosensitizers. SPV devices have self-regulated power conversion efficiency (PCE) and light transmission responding to the incident spectra due to the photoisomerization of SIBT. SIBT isomerize from closed-ring form to open-ring form under UV illumination, accompanied with enhanced visible light absorption and electron delocalization. Therefore, increased PCE and absorption in SPV devices were observed under UV treatment and the devices can be restored gradually to the initial status when kept in dark. The SPV devices have self-regulation of PCE and sunlight transmission responding to the changing sun spectra in different times of a day, providing a proper energy usage and a better sun-shading.

  19. Development of electrochemical photovoltaic cells. Third technical progress report, November 1, 1979-January 31, 1980

    SciTech Connect

    Byker, H.J.; Schwerzel, R.E.; Wood, V.E.; Austin, A.E.; Brooman, E.W.

    1980-03-07

    The development of stable, efficient, electrochemical photovoltaic cells based on silicon and gallium arsenide in non-aqueous electrolyte systems is being investigated. The effect of surface condition of silicon electrodes on electrochemical and physical characteristics has been studied. An electrode-supporting electrolyte interaction in acetonitrile has been identified which leads to etching of the surface. Improved performance can result, which has practical significance. Gallium arsenide electrodes have been electrochemically characterized in cells containing propylene carbonate with a ferrocene/ferricenium redox additive. Degradation of the ferricenium salt under illumination has been investigated. Other redox couples studied to date have not given promising results. Long-term stability experiments have been deferred while a better understanding of electrode behavior is being obtained.

  20. Analyzing luminescent solar concentrators with front-facing photovoltaic cells using weighted Monte Carlo ray tracing

    NASA Astrophysics Data System (ADS)

    Woei Leow, Shin; Corrado, Carley; Osborn, Melissa; Isaacson, Michael; Alers, Glenn; Carter, Sue A.

    2013-06-01

    Luminescent solar concentrators (LSC) collect ambient light from a broad range of angles and concentrate the captured light onto photovoltaic (PV) cells. LSCs with front-facing cells collect direct and indirect sunlight ensuring a gain factor greater than one. The flexible placement and percentage coverage of PV cells on the LSC panel allow for layout adjustments to be made in order to balance re-absorption losses and the level of light concentration desired. A weighted Monte Carlo ray tracing program was developed to study the transport of photons and loss mechanisms in the LSC to aid in design optimization. The program imports measured absorption/emission spectra of an organic luminescent dye (LR305), the transmission coefficient, and refractive index of acrylic as parameters that describe the system. Simulations suggest that for LR305, 8-10 cm of luminescent material surrounding the PV cell yields the highest increase in power gain per unit area of LSC added, thereby determining the ideal spacing between PV cells in the panel. For rectangular PV cells, results indicate that for each centimeter of PV cell width, an additional increase of 0.15 mm to the waveguide thickness is required to efficiently transport photon collected by the LSC to the PV cell with minimal loss.

  1. Basic aspects for improving the energy conversion efficiency of hetero-junction organic photovoltaic cells.

    PubMed

    Ryuzaki, Sou; Onoe, Jun

    2013-01-01

    Hetero-junction organic photovoltaic (OPV) cells consisting of donor (D) and acceptor (A) layers have been regarded as next-generation PV cells, because of their fascinating advantages, such as lightweight, low fabrication cost, resource free, and flexibility, when compared to those of conventional PV cells based on silicon and semiconductor compounds. However, the power conversion efficiency (η) of the OPV cells has been still around 8%, though more than 10% efficiency has been required for their practical use. To fully optimize these OPV cells, it is necessary that the low mobility of carriers/excitons in the OPV cells and the open circuit voltage (V OC), of which origin has not been understood well, should be improved. In this review, we address an improvement of the mobility of carriers/excitons by controlling the crystal structure of a donor layer and address how to increase the V OC for zinc octaethylporphyrin [Zn(OEP)]/C60 hetero-junction OPV cells [ITO/Zn(OEP)/C60/Al]. It was found that crystallization of Zn(OEP) films increases the number of inter-molecular charge transfer (IMCT) excitons and enlarges the mobility of carriers and IMCT excitons, thus significantly improving the external quantum efficiency (EQE) under illumination of the photoabsorption band due to the IMCT excitons. Conversely, charge accumulation of photo-generated carriers in the vicinity of the donor/acceptor (D/A) interface was found to play a key role in determining the V OC for the OPV cells.

  2. Graphene-enhanced thermal interface materials for heat removal from photovoltaic solar cells

    NASA Astrophysics Data System (ADS)

    Saadah, M.; Gamalath, D.; Hernandez, E.; Balandin, A. A.

    2016-09-01

    The increase in the temperature of photovoltaic (PV) solar cells affects negatively their power conversion efficiency and decreases their lifetime. The negative effects are particularly pronounced in concentrator solar cells. Therefore, it is crucial to limit the PV cell temperature by effectively removing the excess heat. Conventional thermal phase change materials (PCMs) and thermal interface materials (TIMs) do not possess the thermal conductivity values sufficient for thermal management of the next generation of PV cells. In this paper, we report the results of investigation of the increased efficiency of PV cells with the use of graphene-enhanced TIMs. Graphene reveals the highest values of the intrinsic thermal conductivity. It was also shown that the thermal conductivity of composites can be increased via utilization of graphene fillers. We prepared TIMs with up to 6% of graphene designed specifically for PV cell application. The solar cells were tested using the solar simulation module. It was found that the drop in the output voltage of the solar panel under two-sun concentrated illumination can be reduced from 19% to 6% when grapheneenhanced TIMs are used. The proposed method can recover up to 75% of the power loss in solar cells.

  3. Nanostructured photovoltaics

    NASA Astrophysics Data System (ADS)

    Fu, Lan; Tan, H. Hoe; Jagadish, Chennupati

    2013-01-01

    Energy and the environment are two of the most important global issues that we currently face. The development of clean and sustainable energy resources is essential to reduce greenhouse gas emission and meet our ever-increasing demand for energy. Over the last decade photovoltaics, as one of the leading technologies to meet these challenges, has seen a continuous increase in research, development and investment. Meanwhile, nanotechnology, which is considered to be the technology of the future, is gradually revolutionizing our everyday life through adaptation and incorporation into many traditional technologies, particularly energy-related technologies, such as photovoltaics. While the record for the highest efficiency is firmly held by multijunction III-V solar cells, there has never been a shortage of new research effort put into improving the efficiencies of all types of solar cells and making them more cost effective. In particular, there have been extensive and exciting developments in employing nanostructures; features with different low dimensionalities, such as quantum wells, nanowires, nanotubes, nanoparticles and quantum dots, have been incorporated into existing photovoltaic technologies to enhance their performance and/or reduce their cost. Investigations into light trapping using plasmonic nanostructures to effectively increase light absorption in various solar cells are also being rigorously pursued. In addition, nanotechnology provides researchers with great opportunities to explore the new ideas and physics offered by nanostructures to implement advanced solar cell concepts such as hot carrier, multi-exciton and intermediate band solar cells. This special issue of Journal of Physics D: Applied Physics contains selected papers on nanostructured photovoltaics written by researchers in their respective fields of expertise. These papers capture the current excitement, as well as addressing some open questions in the field, covering topics including the

  4. Organic photovoltaic cells with stable top metal electrodes modified with polyethylenimine.

    PubMed

    Khan, Talha M; Zhou, Yinhua; Dindar, Amir; Shim, Jae Won; Fuentes-Hernandez, Canek; Kippelen, Bernard

    2014-05-14

    Efficient organic photovoltaic cells (OPV) often contain highly reactive low-work-function calcium electron-collecting electrodes. In this work, efficient OPV are demonstrated in which calcium electrodes were avoided by depositing a thin layer of the amine-containing nonconjugated polymer, polyethylenimine (PEIE), between the photoactive organic semiconductor layer and stable metal electrodes such as aluminum, silver, or gold. Devices with structure ITO/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/poly(3-hexylthiophene):indene-C60-bis-adduct (P3HT:ICBA)/PEIE/Al demonstrated overall photovoltaic device performance comparable to devices containing calcium electron-collecting electrodes, ITO/PEDOT:PSS/P3HT:ICBA/Ca/Al, with open-circuit voltage of 775±6 mV, short-circuit current density of 9.1±0.5 mA cm(-2), fill factor of 0.65±0.01, and power conversion efficiency of 4.6±0.3%, averaged over 5 devices at 1 sun.

  5. Effects of Immersion Solvent on Photovoltaic and Photophysical Properties of Porphyrin-Sensitized Solar Cells.

    PubMed

    Hayashi, Hironobu; Higashino, Tomohiro; Kinjo, Yuriko; Fujimori, Yamato; Kurotobi, Kei; Chabera, Pavel; Sundström, Villy; Isoda, Seiji; Imahori, Hiroshi

    2015-08-26

    Memory effects in self-assembled monolayers (SAMs) of zinc porphyrin carboxylic acid on TiO2 electrodes have been demonstrated for the first time by evaluating the photovoltaic and electron transfer properties of porphyrin-sensitized solar cells prepared by using different immersion solvents sequentially. The structure of the SAM of the porphyrin on the TiO2 was maintained even after treating the porphyrin monolayer with different neat immersion solvents (memory effect), whereas it was altered by treatment with solutions containing different porphyrins (inverse memory effect). Infrared spectroscopy shows that the porphyrins in the SAM on the TiO2 could be exchanged with the same or analogous porphyrin, leading to a change in the structure of the porphyrin SAM. The memory and inverse memory effects are well correlated with a change in porphyrin geometry, mainly the tilt angle of the porphyrin along the long molecular axis from the surface normal on the TiO2, as well as with kinetics of electron transfer between the porphyrin and TiO2. Such a new structure-function relationship for DSSCs will be very useful for the rational design and optimization of photoelectrochemical and photovoltaic properties of molecular assemblies on semiconductor surfaces.

  6. Point-focus spectral splitting solar concentrator for multiple cells concentrating photovoltaic system

    NASA Astrophysics Data System (ADS)

    Maragliano, Carlo; Chiesa, Matteo; Stefancich, Marco

    2015-10-01

    In this paper we present and experimentally validate a low-cost design of a spectral splitting concentrator for the efficient conversion of solar energy. The optical device consists of a dispersive prismatic lens made of polycarbonate designed to simultaneously concentrate solar light and split it into its spectral components. With respect to our previous implementation, this device concentrates light along two axes and generates a light pattern compatible with the dimensions of a set of concentrating photovoltaic cells, while providing a higher concentration ratio. The mathematical framework and the constructive approach used for the design are presented and the device performance is simulated using ray-tracing software. We obtain spectral separation in the visible range within a 3 × 1 cm2 area and a maximum concentration of 210× for a single wavelength. The device is fabricated by injection molding and its performance is experimentally investigated. We measure an optical transmissivity above 90% in the range 400-800 nm and we observe a spectral distribution in good accordance with simulations. Our results demonstrate the feasibility of the device for cost effective high efficiency concentrated photovoltaic systems.

  7. Photovoltaic cells made from conjugated polymers infiltrated into ordered nanoporous hosts

    NASA Astrophysics Data System (ADS)

    Coakley, Kevin M.

    Semiconducting (conjugated) polymers have several properties which make them ideal candidates for use in low-cost photovoltaic (PV) cells, including their typically high (105 cm-1) optical absorption coefficients, their ability to be cast from solution using a variety of wet-processing techniques, and the ability to tune their band gap. While most approaches for making conjugated polymer-based PV cells involve randomly intermixing the polymers with electron acceptors that act as sites for exciton dissociation, we have sought to obtain a more optimized morphology of the blended materials through a self-assembly technique. In the first half of this dissertation, we describe our preliminary attempts to make PV cells from conjugated polymers infiltrated into a self-assembled mesoporous titanic (TiO 2) electron acceptor that is ordered on the nanometer length scale. We first present a procedure for fabricating films of mesoporous TiO 2 and then show how its pores can be filled with a conjugated polymer, regioregular poly(3-hexylthiophene) (P3HT). In these films we have achieved precise control of the morphology of the two materials that has not yet been achieved elsewhere. However, as discussed subsequently, the photovoltaic performance of these films has not yet reached the level achieved by other types of conjugated polymer-based PV cells, with a maximum achieved power efficiency of approximately 0.45%. In the second half of this dissertation, we embark on a more fundamental study of the materials requirements for efficient polymer photovoltaics, including models that show how the maximum achievable power efficiency is limited by energy loss during forward electron transfer, and how the maximum achievable photocurrent is limited by the limiting carrier mobility and back electron transfer. Our modeling suggests that, for a back recombination time constant of 1 mus, a limiting carrier mobility of 10-3--10 -2 cm2/Vs is required in order to achieve a large photocurrent

  8. Optical analysis and thermal management of 2-cell strings linear concentrating photovoltaic system

    NASA Astrophysics Data System (ADS)

    Reddy, K. S.; Kamnapure, Nikhilesh R.

    2015-09-01

    This paper presents the optical and thermal analyses for a linear concentrating photovoltaic/thermal collector under different operating conditions. Linear concentrating photovoltaic system (CPV) consists of a highly reflective mirror, a receiver and semi-dual axis tracking mechanism. The CPV receiver embodies two strings of triple-junction cells (100 cells in each string) adhered to a mild steel circular tube mounted at the focal length of trough. This system provides 560 W of electricity and 1580 W of heat which needs to be dissipated by active cooling. The Al2O3/Water nanofluid is used as heat transfer fluid (HTF) flowing through circular receiver for CPV cells cooling. Optical analysis of linear CPV system with 3.35 m2 aperture and geometric concentration ratio (CR) of 35 is carried out using Advanced System Analysis Program (ASAP) an optical simulation tool. Non-uniform intensity distribution model of solar disk is used to model the sun in ASAP. The impact of random errors including slope error (σslope), tracking error (σtrack) and apparent change in sun's width (σsun) on optical performance of collector is shown. The result from the optical simulations shows the optical efficiency (ηo) of 88.32% for 2-cell string CPV concentrator. Thermal analysis of CPV receiver is carried out with conjugate heat transfer modeling in ANSYS FLUENT-14. Numerical simulations of Al2O3/Water nanofluid turbulent forced convection are performed for various parameters such as nanoparticle volume fraction (φ), Reynolds number (Re). The addition of the nanoparticle in water enhances the heat transfer in the ranges of 3.28% - 35.6% for φ = 1% - 6%. Numerical results are compared with literature data which shows the reasonable agreement.

  9. Low-cost photovoltaics: Luminescent solar concentrators and colloidal quantum dot solar cells

    NASA Astrophysics Data System (ADS)

    Leow, Shin Woei

    Solar energy has long been lauded as an inexhaustible fuel source with more energy reaching the earth's surface in one hour than the global consumption for a year. Although capable of satisfying the world's energy requirements, solar energy remains an expensive technology that has yet to attain grid parity. Another drawback is that existing solar farms require large quantities of land in order to generate power at useful rates. In this work, we look to luminescent solar concentrator systems and quantum dot technology as viable solutions to lowering the cost of solar electricity production with the flexibility to integrate such technologies into buildings to achieve dual land use. Luminescent solar concentrator (LSC) windows with front-facing photovoltaic (PV) cells were built and their gain and power efficiency were investigated. Conventional LSCs employ a photovoltaic (PV) cell that is placed on the edge of the LSC, facing inward. This work describes a new design with the PV cells on the front-face allowing them to receive both direct solar irradiation and wave-guided photons emitted from a dye embedded in an acrylic sheet, which is optically coupled to the PV cells. Parameters investigated include the thickness of the waveguide, edge treatment of the window, cell width, and cell placement. The data allowed us to make projections that aided in designing windows for maximized overall efficiency. A gain in power of 2.2x over the PV cells alone was obtained with PV cell coverage of 5%, and a power conversion efficiency as high as 6.8% was obtained with a PV cell coverage of 31%. Balancing the trade-offs between gain and efficiency, the design with the lowest cost per watt attained a power efficiency of 3.8% and a gain of 1.6x. With the viability of the LSC demonstrated, a weighted Monte-Carlo Ray Tracing program was developed to study the transport of photons and loss mechanisms in the LSC to aid in design optimization. The program imports measured absorption

  10. The Importance of End Groups for Solution-Processed Small-Molecule Bulk-Heterojunction Photovoltaic Cells.

    PubMed

    Duan, Ruomeng; Cui, Yong; Zhao, Yanfei; Li, Chen; Chen, Long; Hou, Jianhui; Wagner, Manfred; Baumgarten, Martin; He, Chang; Müllen, Klaus

    2016-05-10

    End groups in small-molecule photovoltaic materials are important owing to their strong influence on molecular stability, solubility, energy levels, and aggregation behaviors. In this work, a series of donor-acceptor pentads (D2 -A-D1 -A-D2 ) were designed and synthesized, aiming to investigate the effect of the end groups on the materials properties and photovoltaic device performance. These molecules share identical central A-D1 -A triads (with benzodithiophene as D1 and 6-carbonyl-thieno[3,4-b]thiophene as A), but with various D2 end groups composed of alkyl-substituted thiophene (T), thieno[3,2-b]thiophene (TT), and 2,2'-bithiophene (BT). The results indicate a relationship between conjugated segment/alkyl chain length of the end groups and the photovoltaic performance, which contributes to the evolving molecular design principles for high efficiency organic solar cells.

  11. Basic photovoltaics

    SciTech Connect

    Zweibel, K.

    1984-01-01

    Here is a photovoltaics guide that converts highly technical information into language that can be understood by both scientists and non-scientists. It provides an introduction to solar cell technology, explaining how PV cells work, how they are manufactured, and how they are put together into effective energy-producing systems. The authors investigate a new PV technology based on an altered form of silicon capable of producing conversion efficiencies of 10% to 15%. They explain the PV effect, loss mechanisms, and advances in fabrication methods.

  12. Degradation/oxidation susceptibility of organic photovoltaic cells in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Habib, K.; Husain, A.; Al-Hazza, A.

    2015-12-01

    A criterion of the degradation/oxidation susceptibility of organic photovoltaic (OPV) cells in aqueous solutions was proposed for the first time. The criterion was derived based on calculating the limit of the ratio value of the polarization resistance of an OPV cell in aqueous solution (Rps) to the polarization resistance of the OPV cell in air (Rpair). In other words, the criterion lim(Rps/Rpair) = 1 was applied to determine the degradation/oxidation of the OPV cell in the aqueous solution when Rpair became equal (increased) to Rps as a function of time of the exposure of the OPV cell to the aqueous solution. This criterion was not only used to determine the degradation/oxidation of different OPV cells in a simulated operational environment but also it was used to determine the electrochemical behavior of OPV cells in deionized water and a polluted water with fine particles of sand. The values of Rps were determined by the electrochemical impedance spectroscopy at low frequency. In addition, the criterion can be applied under diverse test conditions with a predetermined period of OPV operations.

  13. Performance enhancement technique of visible light communications using passive photovoltaic cell

    NASA Astrophysics Data System (ADS)

    Wu, Jhao-Ting; Chow, Chi-Wai; Liu, Yang; Hsu, Chin-Wei; Yeh, Chien-Hung

    2017-06-01

    The light emitting diode (LED) based visible light communication (VLC) system can provide lighting and communication simultaneously. It has attracted much attenuation recently. As the photovoltaic cell (also known as solar cell) is physically flexible, low cost, and easily available, it could be a good choice for the VLC receiver (Rx). Furthermore, besides acting as the VLC Rx, the solar cell can convert VLC signal into electricity for charging up the Rx devices. Hence, it could be a promising candidate for the future internet-of-thing (IoT) networks. However, using solar cell as VLC Rx is challenging, since the response of the solar cell is highly limited and it will limit the VLC data rate. In this work, we propose and demonstrate for the first time using pre-distortion Manchester coding (MC) signal to enhance the signal performance of solar cell Rx based VLC. The proposed scheme can significantly mitigate the slow response, as well as the direct-current (DC) wandering effect of the solar cell; hence 50 times increase in data rate can be experimentally achieved.

  14. Study on electrical and thermal behavior of organic photovoltaic (OPV) cells

    NASA Astrophysics Data System (ADS)

    Dobre, Robert Alexandru; Ionescu, Ciprian; Vlǎdescu, Marian; NiÅ£ǎ, Valentin Adrian

    2015-02-01

    Organic photovoltaic cells represent a major application of Flexible Organic and Large Area Electronics (FOLAE) field. The advantages of these cells are represented by flexibility and reduced thickness, making them easy to be integrated in electronics designs, removing the necessity of having a large, flat, heavy surface for energy harvesting. Although many studies about the structure1 and chemical reactions that occur exist, not a large amount of information is available about the characteristics that would be useful for an electronics engineer designing an electronic system. This paper presents the investigations of the electrical2 and thermal behavior of OPV cells, offering as results the optimal operating conditions and their evaluation using a comparison with the standard, semiconductor-based cells. Thermal characterization is very important because the targeted light source is the sun. By exposing the panels to sunlight in a summer day will greatly increase the working temperature of the cells, implying the necessity of knowing the impact on their electrical characteristics. The response of the cells at different wavelengths of the incident light, voltage vs. current and output voltage diagrams for different light intensities and different temperatures will be determined. In addition, the behavior of the cell as a light sensor will be investigated and a system that uses organic electronics at both ends: for sensing light intensity and also displaying this information will be built, using an electrochromic display.

  15. Solution-processed core-shell nanowires for efficient photovoltaic cells.

    PubMed

    Tang, Jinyao; Huo, Ziyang; Brittman, Sarah; Gao, Hanwei; Yang, Peidong

    2011-08-21

    Semiconductor nanowires are promising for photovoltaic applications, but, so far, nanowire-based solar cells have had lower efficiencies than planar cells made from the same materials, even allowing for the generally lower light absorption of nanowires. It is not clear, therefore, if the benefits of the nanowire structure, including better charge collection and transport and the possibility of enhanced absorption through light trapping, can outweigh the reductions in performance caused by recombination at the surface of the nanowires and at p-n junctions. Here, we fabricate core-shell nanowire solar cells with open-circuit voltage and fill factor values superior to those reported for equivalent planar cells, and an energy conversion efficiency of ∼5.4%, which is comparable to that of equivalent planar cells despite low light absorption levels. The device is made using a low-temperature solution-based cation exchange reaction that creates a heteroepitaxial junction between a single-crystalline CdS core and single-crystalline Cu2S shell. We integrate multiple cells on single nanowires in both series and parallel configurations for high output voltages and currents, respectively. The ability to produce efficient nanowire-based solar cells with a solution-based process and Earth-abundant elements could significantly reduce fabrication costs relative to existing high-temperature bulk material approaches.

  16. Synergic system between photovoltaic module and microbial fuel cell with simultaneous pollution control

    NASA Astrophysics Data System (ADS)

    Vasyliv, Oresta; Dhere, Neelkanth G.

    2015-05-01

    Combined photovoltaic module-microbial fuel cell construction shows prospect of advanced autonomous functioning effective energy-production system with the possibility of round-the-clock power generation. Application of Desulfuromonas sp. as anode biocatalyst in photovoltaic (PV) - microbial fuel cell (MFC) could support highly effective eco-friendly energy derivation with simultaneous reduction of organic and inorganic wastes in water environment. D. acetoxidans is exoelectrogenic bacterium that supports S0-reduction with H2S formation and S0-oxidation while an electrode serves as the electron acceptor. Simultaneous sulfur redox processes enhance electron transfer to the electrode surface that may increase the effectiveness of microbial fuel cell performance. It was shown that D. acetoxidans IMV B-7384 possesses selective resistance to 0.5-2.5 mM of copper, iron, nickel, manganese and lead ions. Metal-resistant strains of this bacterium may help overcome H2S toxicity, which is produced because of dissimilative S0-reduction, since divalent cations will interact with sulfide ions, forming insoluble precipitates. Thus D. acetoxidans IMV B-7384 may be applied for remediation of toxic metal ions from water environments because of metal fixation in form of insoluble complexes of metal sulfides. D. acetoxidans IMV B-7384 is presumed to have the capability to convert organic compounds, such as malate, pyruvate, succinate and fumarate via reductive stage of tricarboxylic acid cycle. Thus application of effluents as anolyte in MFC, based on D. acetoxidans IMV B-7384, may cause decrease of its organic content with formation of simple benign constituents, such as CO2 and H2O. Hence the advanced system for eco-friendly energy generation with simultaneous water pollution control is proposed.

  17. Solar conversion efficiency of photovoltaic and photoelectrolysis cells with carrier multiplication absorbers

    NASA Astrophysics Data System (ADS)

    Hanna, M. C.; Nozik, A. J.

    2006-10-01

    We calculate the maximum power conversion efficiency for conversion of solar radiation to electrical power or to a flux of chemical free energy for the case of hydrogen production from water photoelectrolysis. We consider several types of ideal absorbers where absorption of one photon can produce more than one electron-hole pair that are based on semiconductor quantum dots with efficient multiple exciton generation (MEG) or molecules that undergo efficient singlet fission (SF). Using a detailed balance model with 1 sun AM1.5G illumination, we find that for single gap photovoltaic (PV) devices the maximum efficiency increases from 33.7% for cells with no carrier multiplication to 44.4% for cells with carrier multiplication. We also find that the maximum efficiency of an ideal two gap tandem PV device increases from 45.7% to 47.7% when carrier multiplication absorbers are used in the top and bottom cells. For an ideal water electrolysis two gap tandem device, the maximum conversion efficiency is 46.0% using a SF top cell and a MEG bottom cell versus 40.0% for top and bottom cell absorbers with no carrier multiplication. We also consider absorbers with less than ideal MEG quantum yields as are observed experimentally.

  18. Porous Silicon Modified Photovoltaic Junctions: An Approach to High-Efficiency Solar Cells

    NASA Astrophysics Data System (ADS)

    Badawy, Waheed A.

    2007-02-01

    The solution of the energy problems of our universe is based on the use of the ultimate source of energy, THE SUN, as the main source of useable energy. The trials to obtain solar cells of appropriate efficiency and suitable price represent one of the main tasks of different research groups over the whole world. In this respect silicon represent the main absorber of sun light that could be converted to electricity, photovoltaic cells, or to high energy chemical products, photoelectrochemical cells. Photovoltaic and photoelectrochemical systems were prepared by the formation of a thin porous film on silicon. The porous silicon layer was formed on the top of a clean oxide free silicon wafer surface by anodic etching in HF/H2O/C2H5OH mixture (2:1:1). The silicon was then covered by an oxide film (tin oxide, ITO or titanium oxide. The oxide films were prepared by the spray/pyrolysis technique which enables the incorporation of foreign atoms like In, Ru or Sb in the oxide film matrix during the spray process/. The incorporation of foreign atoms improves the surface characteristics of the oxide film which leads to the improvement of the fill factor and higher solar conversion efficiency. The prepared solar cells are stable against environmental attack due to the presence of the stable oxide film. It gives relatively high short circuit currents (Isc) compared to our improved silicon single crystal solar cells /6/, due to the presence of the porous silicon layer, which leads to the recorded high conversion efficiency. Although the open-circuit potential (Voc) and fill factor (FF) were not affected by the thickness of the porous silicon film, the short circuit current was found to be sensitive to this thickness. An optimum thickness of the porous film and also the oxide layer is required to optimize the solar cell efficiency. The results represent a promising system for the application of porous silicon layers in solar energy converters. The use of porous silicon instead of

  19. A nanocomposite interconnecting layer for tandem small molecular organic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Luo, D. Y.; Yu, L. M.; Man, J. X.; Liu, Z.; Lu, Z. H.

    2014-03-01

    A nanocomposite interconnecting layer of C60:LiF/Ag/MoOx had been applied in the tandem structure of organic photovoltaic cells to achieve high short circuit current (Jsc) and power conversion efficiency (PCE). The Jsc had been enhanced 40% after applying the nanocomposite interconnecting layer into a tandem structure compared to the conventional interconnecting layer of Bathocuproine (BCP)/Ag/MoOx. The improvement is due to the enhancement of the light absorption of the devices. A tandem device PCE of 3.04% was achieved by further improving the light absorption in the individual subcell units in the tandem structure by means of a bi-functional buffer layer of C60:LiF/BCP.

  20. Photovoltaic characteristics of polymer solar cells fabricated by pre-metered coating process.

    PubMed

    Park, Byoungchoo; Han, Mi-Young

    2009-08-03

    We present the results of a study of flat and uniform poly(3-hexylthiophene):methanofullerene bulk-heterojunction photovoltaic (PV) layers that were produced by a simple pre-metered horizontal-dipping process for the fabrication of polymer solar cells (PSCs). It is shown that this process can produce high quality and thin films by utilizing the downstream meniscus of the solution, which can be controlled by adjusting experimental parameters of the gap height and the carrying speed. It is also shown that the produced PV film exhibits high power conversion efficiency of ca. 4.2% with a large active area. It was demonstrated that this pre-metered process for solution coating may be promising for achieving highly efficient, reliable, and large-area PSCs.

  1. Polymer photovoltaic cells with a graded active region achieved using double stamp transfer printing

    NASA Astrophysics Data System (ADS)

    Joo Cho, Yong; Yeob Lee, Jun; Forrest, Stephen R.

    2013-11-01

    We demonstrate that double stamp transfer printing of the poly(3-hexylthiophene) (P3HT):[6,6]-phenyl C61-butyric acid methyl ester (PCBM) active layer on MoO3 of an organic photovoltaic (OPV) cell enhances the charge collection efficiency at the anode and cathode contacts by creating a concentration gradient of the P3HT and PCBM across the bulk heterojunction active layer. This gradient increases the short circuit current and the power conversion efficiency of stamp-transferred P3HT:PCBM polymer OPVs by 23% compared with that of similarly structured spin-coated polymer OPVs due to the graded active layer composition, resulting in a power conversion efficiency of 3.7 ± 0.2% for an as-cast device. The stamp-transfer printing process provides a route to low cost fabrication of OPVs over large flexible substrate areas.

  2. Enhanced photovoltaic performance of organic/silicon nanowire hybrid solar cells by solution-evacuated method.

    PubMed

    Wang, Wei-Li; Zou, Xian-Shao; Zhang, Bin; Dong, Jun; Niu, Qiao-Li; Yin, Yi-An; Zhang, Yong

    2014-06-01

    A method has been developed to fabricate organic-inorganic hybrid heterojunction solar cells based on n-type silicon nanowire (SiNW) and poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) hybrid structures by evacuating the PEDOT:PSS solution with dip-dropping on the top of SiNWs before spin-coating (solution-evacuating). The coverage and contact interface between PEDOT:PSS and SiNW arrays can be dramatically enhanced by optimizing the solution-evacuated time. The maximum power conversion efficiency (PCE) reaches 9.22% for a solution-evacuated time of 2 min compared with 5.17% for the untreated pristine device. The improvement photovoltaic performance is mainly attributed to better organic coverage and contact with an n-type SiNW surface.

  3. A combined theoretical and experimental investigation on the transient photovoltage in organic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Yao, Yao; Sun, Xiaoyu; Ding, Baofu; Li, De-Li; Hou, Xiaoyuan; Wu, Chang-Qin

    2010-05-01

    We present a time-dependent device model, describing the dynamical processes of both exciton induced by light illumination and charge carriers created from the exciton dissociation, to calculate the transient photovoltage (TPV) in single-layer organic photovoltaic cells. With reasonable parameters for the specific ITO (indium tin oxide)/CuPc (copper phthalocyanine)/Al (aluminum) structure, we could obtain the TPV well fitted with previous experimental observation by adjusting only the intensity of input laser pulse. Further, we saw a saturation of this TPV by changing the intensity of laser pulse from the calculation, which has been confirmed by the experimental measurement on ITO/NPB [N,N-bis(l-naphthyl)-N,N-diphenyl-1,l-biphentl-4,4-diamine]/Al structure. The saturated TPV value is found to be sensitive to the mobility of minority carriers, which might be useful in the estimation of mobilities.

  4. Architectures and criteria for the design of high efficiency organic photovoltaic cells

    DOEpatents

    Rand, Barry; Forrest, Stephen R; Pendergrast Burk, Diane

    2015-03-31

    A method for fabricating an organic photovoltaic cell includes providing a first electrode; depositing a series of at least seven layers onto the first electrode, each layer consisting essentially of a different organic semiconductor material, the organic semiconductor material of at least an intermediate layer of the sequence being a photoconductive material; and depositing a second electrode onto the sequence of at least seven layers. One of the first electrode and the second electrode is an anode and the other is a cathode. The organic semiconductor materials of the series of at least seven layers are arranged to provide a sequence of decreasing lowest unoccupied molecular orbitals (LUMOs) and a sequence of decreasing highest occupied molecular orbitals (HOMOs) across the series from the anode to the cathode.

  5. Effect of temperature on carrier formation efficiency in organic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Moritomo, Yutaka; Yonezawa, Kouhei; Yasuda, Takeshi

    2014-08-01

    The internal quantum efficiency ( ϕ IQ) of an organic photovoltaic cell is governed by plural processes. Here, we propose that ϕ IQ can be experimentally decomposed into carrier formation ( ϕ CF) and carrier transfer ( ϕ CT) efficiencies. By combining femtosecond time-resolved and electrochemical spectroscopy, we clarified the effect of temperature on ϕ CF in a regioregular poly(3-hexylthiophene) (rr-P3HT)/[6,6]-phenyl C61-butyric acid methyl ester blend film. We found that ϕ CF ( = 0.55 ) at 80 K is the same as that (=0.55) at 300 K. The temperature insensitivity of ϕ CF indicates that the electron-hole pairs at the D/A interface are seldom subjected to coulombic binding energy.

  6. Directing energy transport in organic photovoltaic cells using interfacial exciton gates.

    PubMed

    Menke, S Matthew; Mullenbach, Tyler K; Holmes, Russell J

    2015-04-28

    Exciton transport in organic semiconductors is a critical, mediating process in many optoelectronic devices. Often, the diffusive and subdiffusive nature of excitons in these systems can limit device performance, motivating the development of strategies to direct exciton transport. In this work, directed exciton transport is achieved with the incorporation of exciton permeable interfaces. These interfaces introduce a symmetry-breaking imbalance in exciton energy transfer, leading to directed motion. Despite their obvious utility for enhanced exciton harvesting in organic photovoltaic cells (OPVs), the emergent properties of these interfaces are as yet uncharacterized. Here, directed exciton transport is conclusively demonstrated in both dilute donor and energy-cascade OPVs where judicious optimization of the interface allows exciton transport to the donor-acceptor heterojunction to occur considerably faster than when relying on simple diffusion. Generalized systems incorporating multiple exciton permeable interfaces are also explored, demonstrating the ability to further harness this phenomenon and expeditiously direct exciton motion, overcoming the diffusive limit.

  7. Correlation between the Open-Circuit Voltage and Charge Transfer State Energy in Organic Photovoltaic Cells.

    PubMed

    Zou, Yunlong; Holmes, Russell J

    2015-08-26

    In order to further improve the performance of organic photovoltaic cells (OPVs), it is essential to better understand the factors that limit the open-circuit voltage (VOC). Previous work has sought to correlate the value of VOC in donor-acceptor (D-A) OPVs to the interface energy level offset (EDA). In this work, measurements of electroluminescence are used to extract the charge transfer (CT) state energy for multiple small molecule D-A pairings. The CT state as measured from electroluminescence is found to show better correlation to the maximum VOC than EDA. The difference between EDA and the CT state energy is attributed to the Coulombic binding energy of the CT state. This correlation is demonstrated explicitly by inserting an insulating spacer layer between the donor and acceptor materials, reducing the binding energy of the CT state and increasing the measured VOC. These results demonstrate a direct correlation between maximum VOC and CT state energy.

  8. Delocalization and dielectric screening of charge transfer states in organic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Bernardo, B.; Cheyns, D.; Verreet, B.; Schaller, R. D.; Rand, B. P.; Giebink, N. C.

    2014-02-01

    Charge transfer (CT) states at a donor-acceptor heterojunction have a key role in the charge photogeneration process of organic solar cells, however, the mechanism by which these states dissociate efficiently into free carriers remains unclear. Here we explore the nature of these states in small molecule-fullerene bulk heterojunction photovoltaics with varying fullerene fraction and find that the CT energy scales with dielectric constant at high fullerene loading but that there is a threshold C60 crystallite size of ~4 nm below which the spatial extent of these states is reduced. Electroabsorption measurements indicate an increase in CT polarizability when C60 crystallite size exceeds this threshold, and that this change is correlated with increased charge separation yield supported by CT photoluminescence transients. These results support a model of charge separation via delocalized CT states independent of excess heterojunction offset driving energy and indicate that local fullerene crystallinity is critical to the charge separation process.

  9. Enhanced exciton diffusion in an organic photovoltaic cell by energy transfer using a phosphorescent sensitizer

    NASA Astrophysics Data System (ADS)

    Luhman, Wade A.; Holmes, Russell J.

    2009-04-01

    We demonstrate enhanced exciton diffusion in an organic photovoltaic cell through the incorporation of a phosphorescent sensitizer. The increase in exciton diffusion length (LD) is realized using a composite electron donor layer consisting of a N ,N'-bis(naphthalen-1-yl)-N ,N'-bis(phenyl)-benzidine (NPD) host doped with the phosphorescent guest fac-tris(2-phenylpyridine) iridium [Ir(ppy)3]. The presence of the phosphor at low concentration allows for the population of the long-lived NPD triplet state and an increase in LD. An increase in the NPD LD from 6.5±0.3 to 11.8±0.6 nm is extracted from measurements of the external quantum efficiency for donor layers containing 5 wt % Ir(ppy)3. This enhancement leads to a ˜80% improvement in the power conversion efficiency relative to devices containing an undoped donor layer.

  10. Effect of temperature on carrier formation efficiency in organic photovoltaic cells

    SciTech Connect

    Moritomo, Yutaka Yonezawa, Kouhei; Yasuda, Takeshi

    2014-08-18

    The internal quantum efficiency (ϕ{sub IQ}) of an organic photovoltaic cell is governed by plural processes. Here, we propose that ϕ{sub IQ} can be experimentally decomposed into carrier formation (ϕ{sub CF}) and carrier transfer (ϕ{sub CT}) efficiencies. By combining femtosecond time-resolved and electrochemical spectroscopy, we clarified the effect of temperature on ϕ{sub CF} in a regioregular poly(3-hexylthiophene) (rr-P3HT)/[6,6]-phenyl C{sub 61}-butyric acid methyl ester blend film. We found that ϕ{sub CF} (=0.55) at 80 K is the same as that (=0.55) at 300 K. The temperature insensitivity of ϕ{sub CF} indicates that the electron-hole pairs at the D/A interface are seldom subjected to coulombic binding energy.

  11. Characterization of local electrochemical doping of high performance conjugated polymer for photovoltaics using scanning droplet cell microscopy.

    PubMed

    Gasiorowski, Jacek; Mardare, Andrei Ionut; Sariciftci, Niyazi Serdar; Hassel, Achim Walter

    2013-12-15

    The electrochemical oxidation of a next generation low bandgap high performance photovoltaic material namely poly[4,8-bis-substituted-benzo[1,2-b:4,5-b0]dithiophene-2,6-diyl-alt-4-substituted-thieno[3,4-b] thiophene-2,6-diyl] (PBDTTT-c) thin film was investigated using a scanning droplet cell microscope. Cyclic voltammetry was used for the basic characterization of the oxidation/doping of PBDTTT-c. Application of the different final potentials during the electrochemical study provides a close look to the oxidation kinetics. The electrical properties of both doped and undoped PBDTTT-c were analyzed in situ by electrochemical impedance spectroscopy giving the possibility to correlate the changes in the doping level with the subsequent changes in the resistance and capacitance. As a result one oxidation peak was found during the cyclic voltammetry and in potentiostatic measurements. From Mott-Schottky analysis a donor concentration of 2.3 × 10(20) cm(-3) and a flat band potential of 1.00 V vs. SHE were found. The oxidation process resulted in an increase of the conductivity by two orders of magnitude reaching a maximum for the oxidized form of 1.4 S cm(-1).

  12. Effect of sulfur doped TiO2 on photovoltaic properties of dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Seo, Hyunwoong; Nam, Sang-Hun; Itagaki, Naho; Koga, Kazunori; Shiratani, Masaharu; Boo, Jin-Hyo

    2016-07-01

    In a dye-sensitized solar cell (DSC), a nano-porous semiconductor layer plays an important role in the performance. It determines open-circuit voltage and it affects the dye adsorption capacity and charge transfer, which are closely associated with photocurrent and overall performance. TiO2 is the most proper material for nano-porous layer since the first development of DSCs. This work focuses on the enhancement of TiO2 by doping. Sulfur (S) doping enhances charge transfer and the photoconversion of TiO2. Therefore, the increase in photocurrent and efficiency is expected by S doping. S is doped into TiO2 by hydrolysis method. The amount of S is varied and their photo-responses are verified. The most effective S doped TiO2 is applied to DSCs. Overall performance of DSC is enhanced by the addition of S doped TiO2. Especially, the photocurrent is much increased by the improvement on charge transfer, electron lifetime, and photo-conversion. The photovoltaic properties of DSCs are investigated with various ratios of undoped and S doped TiO2. Finally, a DSC based on undoped and S doped TiO2 ratio of 1:1 has the highest efficiency, better than that of a standard DSC based on undoped TiO2. [Figure not available: see fulltext.

  13. Next Generation Photovoltaics Based on Multiple Exciton Generation in Quantum Dot Solar Cells

    NASA Astrophysics Data System (ADS)

    Nozik, Arthur J.

    Next Generation solar cells based onMultiple Exciton Generation (MEG) in semiconductorquantum dots (QDs) are described. This application of QDs depends upon efficient MEG in QDs incorporated into PV cells, followed by efficient exciton splitting into free electrons and holes and their efficient separation and collection in the cell contacts to produce multiple free carriers per absorbed photon. Using time-resolved transient absorption, bleaching, photoluminescence and THz spectroscopy, MEG has been initially confirmed in several Group IV-VI, III-V, II-VI, and IV colloidal semiconductor QDs. Some controversy using these techniques have now been attributed to effects of the variable of the QD surface chemisty and under certain conditions to artifacts arising from long-lived trapping of photoinduced charge; in our opinion these controversies have been resolved and are discussed here. Furthermore, various photovoltaic cell architectures utilizing QDs have recently been constructed and the photocurrent and photovoltage characterisitics have been studied. These photocurrent measurements provide a more direct measurement of MEG since the photogenerated carriers are counted directly via the current, and they are very consistent with the QYs of MEG reported using the proper spectroscopic techniques; thus, these new photocurrent measurements confirm the existence of enhanced exciton and carrier multiplication in QDs. The past work and prognosis for QD-based Next Generation PV cells based on MEG are discussed.

  14. The Mechanical Properties of III-V Compound Semiconductors Used in High Efficiency Multijunction Photovoltaic Cells

    NASA Astrophysics Data System (ADS)

    Zakaria, Abdallah

    Lattice-mismatched heteroepitaxy enables the fabrication of metamorphic solar cells that have reached record light conversion efficiencies in the last five years. These devices are accelerating the commercialization of concentrator photovoltaics that can compete with fossil fuels for terrestrial energy production. A critical part of metamorphic structures is the graded buffer layer (GBL) needed to progressively change the lattice constant of the substrate to that the epilayer of interest. The effectiveness of the graded buffer layer in relieving misfit strain affects the quality of the device grown and depends on a variety of parameters. This study focuses on the mechanical properties of semiconductor compounds used in graded buffer layers. First, the effect of compound semiconductor spontaneous atomic ordering on hardness is assessed. In1--xGaxP was deposited on Ge wafers in two structures. A surfactant was used in experiment A to induce a lower degree of order. High resolution x-ray diffraction (HRXRD) estimated a theoretical band gap energy Eg corrected for strain effects. Photoluminescence measured the actual Eg. By comparing the two, the degree of order eta was determined to be 0.12-0.15 for samples A and 0.43-0.44 for samples B. Atomic force microscopy (AFM) demonstrated that all wafers had an equivalent surface roughness of 6.1-7.4 A. Nanoindentation measurements determined that the degree of order has no effect on the hardness of InGaP. Using 1/2 (115) superlattice reflection scans, the InGaP ordered domains size was estimated to be 28.5 nm for sample B1. No superlattice peak was detected in sample A1. The large ordered domain size in B1 explains why no order-hardening behavior was observed in InGaP. Second, a correlation between the composition of a ternary compound semiconductor and hardness is established and the effect of oxidation is determined. A structure consisting of three different AlxGa1--xAs layers separated by In0.01Ga0.99As etch stops was

  15. Photovoltaic characteristics of each subcell evaluated in situ in a triple-junction solar cell

    NASA Astrophysics Data System (ADS)

    Huang, Tzu-Hsuan; Lo, Hao; Lo, Chieh; Wu, Meng-Chyi; Lour, Wen-Shiung

    2016-12-01

    New manufacturing processes were proposed to evaluate important photovoltaic properties of each subcell in an InGaP/InGaAs/Ge triple-junction solar cell. In addition to the triple-junction cell, an InGaAs/Ge double-junction cell and a Ge single-junction cell were also fabricated and employed for evaluation. The key merit of the double-junction cell is that semiconductor layers of forming InGaP top subcell are retained as a dummy top subcell. Thus, the InGaAs middle subcells in both triple- and double-junction cells will receive the same light spectrum. Similarly, the Ge single-junction cell is fabricated with dummy top and middle subcells as light filters. Open-circuit voltage, short-circuit current, conversion efficiency, and current mismatched ratio were measured for evaluating and optimizing each subcell. It is found that Open-circuit voltages are 1.295, 0.967, and 0.212 V for the InGaP, InGaAs, and Ge subcells with temperature coefficients of -2.5, -1.99, and -1.87 mV/°C. Thus the Ge subcell no longer acts a real solar cell at temperature over ∼140 °C. Besides, effect of ambient temperature on short circuit currents of all as-fabricated solar cells is not relevant. The current mismatched ratios are 18.6-20% at temperature ranged from 25 °C to 80 °C. A low efficiency of ∼18.7% is due partly to the poor current match. However, the processing concept proposed is useful as a method of matching currents among the subcells.

  16. The influence of active cell design on a monolithic organic photovoltaic module: fabrication and simulation

    NASA Astrophysics Data System (ADS)

    Lyu, Hong-Kun; Sim, Jun Hyoung; Jeong, Seonju; Woo, Sung-Ho; Shin, Jang-Kyoo; Han, Yoon Soo

    2011-09-01

    In this study, the influence of an active cell design on the power conversion efficiency (PCE) of a monolithic organic photovoltaic (OPV) module was investigated using experimental methods and circuit simulation. For circuit simulation using computer simulation-based study, the organic PV cell was described by a circuit-based two-diode model and the modules were simulated under several conditions including shading effect, diode model parameters, series resistance and shunt resistance, etc. A unit organic PV cell as a reference device and four types of monolithic organic PV modules with different active cell length were fabricated together on the same glass substrate. The characteristics of the fabricated unit OPV cell were measured and the electrical parameters were extracted to use them for the simulation of four types of monolithic organic PV modules. To analyze the influence of OPV cell design on the PCE of monolithic organic PV modules, the current-voltage (I-V) characteristic curves and the PCEs of the four type monolithic OPV modules with different active cell length were obtained and compared with the simulated results. The simulated I-V curves were matched well with the measured I-V curves for the four types of monolithic organic PV modules with different active cell length. The highest PCE of the monolithic OPV module was 2.86 % with the active cell length of 11.6 mm. We expect that this work is meaningful to enhance the performance of a monolithic OPV module to a certain extent and it offers a method to design a high-efficiency large-area monolithic OPV module.

  17. Light Harvesting for Organic Photovoltaics.

    PubMed

    Hedley, Gordon J; Ruseckas, Arvydas; Samuel, Ifor D W

    2017-01-25

    The field of organic photovoltaics has developed rapidly over the last 2 decades, and small solar cells with power conversion efficiencies of 13% have been demonstrated. Light absorbed in the organic layers forms tightly bound excitons that are split into free electrons and holes using heterojunctions of electron donor and acceptor materials, which are then extracted at electrodes to give useful electrical power. This review gives a concise description of the fundamental processes in photovoltaic devices, with the main emphasis on the characterization of energy transfer and its role in dictating device architecture, including multilayer planar heterojunctions, and on the factors that impact free carrier generation from dissociated excitons. We briefly discuss harvesting of triplet excitons, which now attracts substantial interest when used in conjunction with singlet fission. Finally, we introduce the techniques used by researchers for characterization and engineering of bulk heterojunctions to realize large photocurrents, and examine the formed morphology in three prototypical blends.

  18. Light Harvesting for Organic Photovoltaics

    PubMed Central

    2016-01-01

    The field of organic photovoltaics has developed rapidly over the last 2 decades, and small solar cells with power conversion efficiencies of 13% have been demonstrated. Light absorbed in the organic layers forms tightly bound excitons that are split into free electrons and holes using heterojunctions of electron donor and acceptor materials, which are then extracted at electrodes to give useful electrical power. This review gives a concise description of the fundamental processes in photovoltaic devices, with the main emphasis on the characterization of energy transfer and its role in dictating device architecture, including multilayer planar heterojunctions, and on the factors that impact free carrier generation from dissociated excitons. We briefly discuss harvesting of triplet excitons, which now attracts substantial interest when used in conjunction with singlet fission. Finally, we introduce the techniques used by researchers for characterization and engineering of bulk heterojunctions to realize large photocurrents, and examine the formed morphology in three prototypical blends. PMID:27951633

  19. Simulation and optimization of the performance of organic photovoltaic cells based on capped copolymers for bulk heterojunctions

    NASA Astrophysics Data System (ADS)

    Mhamdi, A.; Boukhili, W.; Raissi, M.; Mahdouani, M.; Vignau, L.; Bourguiga, R.

    2016-08-01

    Recently many investigations have been done to improve the performance of solar cells photovoltaic. One of this devices developed is the Bulk Heterojunction (BHJ) solar cells based on poly (3-hexylthiophene) (P3HT)/[6, 6]-phenyl C61-butyric acid methyl ester (PCBM) blend which have been fabricated by spin-coating. It is known that the nanostructure of the active layer of this device has an important impact on the photovoltaic performances. In this work, we analyze the results obtained on solar cells using a copolymer P3HT-b-PS based on poly (3-hexylthiophene) (P3HT) as a donor block and polystyrene (PS) as a soft block, their compatibility with the blend of P3HT/PCBM at various weight percentages (0%-5%). The addition of this weight percentage is in order to improve the performance of polymer solar cells. It has been demonstrated that the addition of a small amount of P3HT-b-PS (from 0.5%-1.5%) led to an increase in photovoltaic efficiency compared to devices made from P3HT/PCBM only. To study the impact of the added amount of the P3HT-b-PS on the performances of the fabricated organic cells, we used an equivalent circuit model based on single diode model with five photovoltaic parameters. Then, we extracted these physical parameters of the organic photovoltaic cells such as the saturation current density, the series and shunt resistances, the ideality factor and the photogenerated current density from the experimental characteristics (J-V) in the dark and under illumination. We proposed and developed the used procedure based on this model and we resolved the analytic equations of the density-current using the Lambert W-function. A good agreement between the theoretical model and the experimental data of electrical characteristics is obtained illustrating the enhancement of the addition of a small amount of P3HT-b-PS (≤1.5%) in the P3HT/PCBM blend on the characteristics of BHJ organic photovoltaic cells.

  20. Effect of annealing copper phthalocyanine on the performance of interdigitated bulk-heterojunction organic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Wang, N. N.; Yu, J. S.; Yuan, Z. L.; Jiang, Y. D.

    2012-05-01

    Organic photovoltaic (OPV) cells with improved efficiency using thermal annealing-induced nanostructured copper phthalocyanine as a donor layer were fabricated. A power conversion efficiency of 1.47% in the OPV cell with interdigitated CuPc/C60 bulk heterojunction has been obtained under AM 1.5 solar illumination at an intensity of 100 mW/cm2, which is higher than 0.63% of CuPc/C60 planar cell. Through varying the annealing temperature of CuPc films, the influence of interface morphology and crystallinity of CuPc films on the performance of OPV cells was systematically studied. Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and spectrophotometry were used to characterize the CuPc films. The results showed that at an optimal annealing temperature, the crystalline nature and vertical orientation of nanostructured CuPc have been modified, which can facilitate the separation of interfacial electron-hole pairs and charge carrier transport to electrodes.

  1. Inverted Polymeric Photovoltaic Cells and Parallel Tandems with Transparent Single Wall Carbon Nanotubes Interlayer

    NASA Astrophysics Data System (ADS)

    Mielczarek, Kamil; Cook, Alex; Zakhidov, Anvar; Kaskela, Antti; Nasibulin, Albert; Kauppinen, Esko

    2011-03-01

    We demonstrate an organic photovoltaic (OPV) monolithic multi junction cell in a parallel electrical configuration utilizing polymers with complementary absorption spectra and transparent single wall CNT (SWCNT) as an interlayer electrode (IE). Parallel tandem cells are of importance because they can append to the limited spectral coverage of available polymers and because there is no need balance current as is the case with in-series configurations. Devices comprise of polymeric sub cells where one is inverted using ZnO nanoparticles and a Mo O3 buffer layers, this inverted structure allows for the SWCNT IE to function as a cathode. Each sub cell is characterized independently and the short circuit current of the tandem device is shown to increase. Overall increase in efficiency is observed and attributed to enhanced spectral coverage by spectrally complimentary polymers and the effective use of parallel tandem architecture. We also demonstrate a semi transparent inverted OPV structure with a SWCNT electrode and a efficiency of over 3%. Supported by AFRL/Rice and Welch AT 16-17 grants.

  2. Device and morphological engineering of organic solar cells for enhanced charge transport and photovoltaic performance

    NASA Astrophysics Data System (ADS)

    Adhikari, Nirmal; Khatiwada, Devendra; Dubey, Ashish; Qiao, Qiquan

    2015-01-01

    Conjugated polymers are potential materials for photovoltaic applications due to their high absorption coefficient, mechanical flexibility, and solution-based processing for low-cost solar cells. A bulk heterojunction (BHJ) structure made of donor-acceptor composite can lead to high charge transfer and power conversion efficiency. Active layer morphology is a key factor for device performance. Film formation processes (e.g., spray-coating, spin-coating, and dip-coating), post-treatment (e.g., annealing and UV ozone treatment), and use of additives are typically used to engineer the morphology, which optimizes physical properties, such as molecular configuration, miscibility, lateral and vertical phase separation. We will review electronic donor-acceptor interactions in conjugated polymer composites, the effect of processing parameters and morphology on solar cell performance, and charge carrier transport in polymer solar cells. This review provides the basis for selection of different processing conditions for optimized nanomorphology of active layers and reduced bimolecular recombination to enhance open-circuit voltage, short-circuit current density, and fill factor of BHJ solar cells.

  3. Nanopillar Photovoltaics: Photon Management and Junction Engineering for Next-Generation Solar Cells

    NASA Astrophysics Data System (ADS)

    Mariani, Giacomo

    The sun delivers an amount of energy equivalent to ninety billion hydrogen bombs detonating each second. Despite the fact that only one billionth of that energy falls onto the surface of the Earth, one day of sunlight would be sufficient to power the whole human race energy needs for over half a century. Solar electricity represents an environmentally-benign source of power. However, such technology is still more than twice as expensive as natural gas-fired generators. III-V semiconductor nanopillars are defined as vertically aligned arrays of nanostructures that hold the promise to aggressively diminish the cost of the active photovoltaic cell by exploiting a fraction of material utilized in conventional planar schemes. In this dissertation, we assess the viability of two classes of high-performance nanopillar-based solar cells. We begin with the incorporation of dedicated conjugated polymers to achieve a hybrid organic/inorganic heterojunction. Such configuration introduces a high optical absorption arising from the polymeric layer in conjunction with an efficient carrier transport resulting from the semiconductor nanopillar array. We extend the controllability of the heterojunction properties by replacing traditional spin-casting methods with an electrodeposition technique where the polymer is formed and doped in-situ directly onto the nanopillar facets. The rational tuning of the electrical conductivity and energy level of the polymer translates into an enhanced photocurrent and open-circuit voltage, achieving 4.11% solar power conversion efficiency. We then turn our attention to all-semiconductor radial p-n homojunctions embedded in the nanopillars. The first architecture focuses on ex-situ ammonium-sulfide passivation and correlates the optoelectronic properties of the solar cell once two different types of transparent conducting oxides are adopted. The barrier formed at the contact/semiconductor interface greatly depends on the Hall polarity of the

  4. Basic aspects for improving the energy conversion efficiency of hetero-junction organic photovoltaic cells

    PubMed Central

    Ryuzaki, Sou; Onoe, Jun

    2013-01-01

    Hetero-junction organic photovoltaic (OPV) cells consisting of donor (D) and acceptor (A) layers have been regarded as next-generation PV cells, because of their fascinating advantages, such as lightweight, low fabrication cost, resource free, and flexibility, when compared to those of conventional PV cells based on silicon and semiconductor compounds. However, the power conversion efficiency (η) of the OPV cells has been still around 8%, though more than 10% efficiency has been required for their practical use. To fully optimize these OPV cells, it is necessary that the low mobility of carriers/excitons in the OPV cells and the open circuit voltage (V OC), of which origin has not been understood well, should be improved. In this review, we address an improvement of the mobility of carriers/excitons by controlling the crystal structure of a donor layer and address how to increase the V OC for zinc octaethylporphyrin [Zn(OEP)]/C60 hetero-junction OPV cells [ITO/Zn(OEP)/C60/Al]. It was found that crystallization of Zn(OEP) films increases the number of inter-molecular charge transfer (IMCT) excitons and enlarges the mobility of carriers and IMCT excitons, thus significantly improving the external quantum efficiency (EQE) under illumination of the photoabsorption band due to the IMCT excitons. Conversely, charge accumulation of photo-generated carriers in the vicinity of the donor/acceptor (D/A) interface was found to play a key role in determining the V OC for the OPV cells. PMID:23853702

  5. Homogeneous PCBM layers fabricated by horizontal-dip coating for efficient bilayer heterojunction organic photovoltaic cells.

    PubMed

    Huh, Yoon Ho; Bae, In-Gon; Jeon, Hong Goo; Park, Byoungchoo

    2016-10-31

    We herein report a homogeneous [6,6]-phenyl C61 butyric acid methyl ester (PCBM) layer, produced by a solution process of horizontal-dipping (H-dipping) to improve the photovoltaic (PV) effects of bilayer heterojunction organic photovoltaic cells (OPVs) based on a bi-stacked poly(3-hexylthiophene) (P3HT) electron donor layer and a PCBM electron acceptor layer (P3HT/PCBM). It was shown that a homogeneous and uniform coating of PCBM layers in the P3HT/PCBM bilayer OPVs resulted in reliable and reproducible device performance. We recorded a power conversion efficiency (PCE) of 2.89%, which is higher than that (2.00%) of bilayer OPVs with a spin-coated PCBM layer. Moreover, introducing surfactant additives of poly(oxyethylene tridecyl ether) (PTE) into the homogeneous P3HT/PCBM PV layers resulted in the bilayer OPVs showing a PCE value of 3.95%, which is comparable to those of conventional bulk-heterojunction (BHJ) OPVs (3.57-4.13%) fabricated by conventional spin-coating. This improved device performance may be attributed to the selective collection of charge carriers at the interfaces among the active layers and electrodes due to the PTE additives as well as the homogeneous formation of the functional PCBM layer on the P3HT layer. Furthermore, H-dip-coated PCBM layers were deposited onto aligned P3HT layers by a rubbing technique, and the rubbed bilayer OPV exhibited improved in-plane anisotropic PV effects with PCE anisotropy as high as 1.81, which is also higher than that (1.54) of conventional rubbed BHJ OPVs. Our results suggest that the use of the H-dip-coating process in the fabrication of PCBM layers with the PTE interface-engineering additive could be of considerable interest to those seeking to improve PCBM-based opto-electrical organic thin-film devices.

  6. Donor/Acceptor Molecular Orientation-Dependent Photovoltaic Performance in All-Polymer Solar Cells.

    PubMed

    Zhou, Ke; Zhang, Rui; Liu, Jiangang; Li, Mingguang; Yu, Xinhong; Xing, Rubo; Han, Yanchun

    2015-11-18

    The correlated donor/acceptor (D/A) molecular orientation plays a crucial role in solution-processed all-polymer solar cells in term of photovoltaic performance. For the conjugated polymers PTB7-th and P(NDI2OD-T2), the preferential molecular orientation of neat PTB7-th films kept face-on regardless of the properties of processing solvents. However, an increasing content of face-on molecular orientation in the neat P(NDI2OD-T2) films could be found by changing processing solvents from chloronaphthalene (CN) and o-dichlorobenzene (oDCB) to chlorobenzene (CB). Besides, the neat P(NDI2OD-T2) films also exhibited a transformation of preferential molecular orientation from face-on to edge-on when extending film drying time by casting in the same solution. Consequently, a distribution diagram of molecular orientation for P(NDI2OD-T2) films was depicted and the same trend could be observed for the PTB7-th/P(NDI2OD-T2) blend films. By manufacture of photovoltaic devices with blend films, the relationship between the correlated D/A molecular orientation and device performance was established. The short-circuit current (Jsc) of devices processed by CN, oDCB, and CB enhanced gradually from 1.24 to 8.86 mA/cm(2) with the correlated D/A molecular orientation changing from face-on/edge-on to face-on/face-on, which could be attributed to facile exciton dissociation at D/A interface with the same molecular orientation. Therefore, the power conversion efficiency (PCE) of devices processed by CN, oDCB, and CB improved from 0.53% to 3.52% ultimately.

  7. Solar photovoltaic systems

    NASA Technical Reports Server (NTRS)

    Forney, R. G.

    1978-01-01

    The Department of Energy's photovoltaic program is outlined. The main objective of the program is the development of low cost reliable terrestrial photovoltaic systems. A second objective is to foster widespread use of the system in residential, industrial and commercial application. The system is reviewed by examining each component; silicon solar cell, silicon solar cell modules, advanced development modules and power systems. Cost and applications of the system are discussed.

  8. Determination of limiting factors of photovoltaic efficiency in quantum dot sensitized solar cells: Correlation between cell performance and structural properties

    NASA Astrophysics Data System (ADS)

    Giménez, Sixto; Lana-Villarreal, Teresa; Gómez, Roberto; Agouram, Said; Muñoz-Sanjosé, V.; Mora-Seró, Iván

    2010-09-01

    Semiconductor quantum dots (QDs) are important candidates as light absorbing materials in low cost and high efficiency sensitized solar cells (SCs). We present a combination of structural, chemical, electrical, and optical characterization that provides insight to the photovoltaic efficiencies of devices formed by TiO2 electron conducting oxide network sensitized with CdSe. In devices using colloidal QDs the collection efficiency under short circuit conditions (CESCs) for photoinjected electrons is rather high (˜90%) but the photovoltaic performance is limited by the low loading of QDs into the mesoporous TiO2 structure. On the other hand, chemical bath deposited (CBD) QDSCs exhibit a remarkably high optical density, but only slightly higher short circuit current and efficiency. It is observed that CESC is ˜50% due to the high recombination rates of the closed packed QDs structure. Our results indicate routes for improvement of QDSCs performance by the increase in colloidal QDs loading and the reduction in recombination in QDs grown in situ.

  9. Organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Leo, Karl

    2016-08-01

    Organic photovoltaics are on the verge of revolutionizing building-integrated photovoltaics. For other applications, however, several basic open scientific questions need answering to, in particular, further improve energy-conversion efficiency and lifetime.

  10. Photovoltaic fibers

    NASA Astrophysics Data System (ADS)

    Gaudiana, Russell; Eckert, Robert; Cardone, John; Ryan, James; Montello, Alan

    2006-08-01

    It was realized early in the history of Konarka that the ability to produce fibers that generate power from solar energy could be applied to a wide variety of applications where fabrics are utilized currently. These applications include personal items such as jackets, shirts and hats, to architectural uses such as awnings, tents, large covers for cars, trucks and even doomed stadiums, to indoor furnishings such as window blinds, shades and drapes. They may also be used as small fabric patches or fiber bundles for powering or recharging batteries in small sensors. Power generating fabrics for clothing is of particular interest to the military where they would be used in uniforms and body armor where portable power is vital to field operations. In strong sunlight these power generating fabrics could be used as a primary source of energy, or they can be used in either direct sunlight or low light conditions to recharge batteries. Early in 2002, Konarka performed a series of proof-of-concept experiments to demonstrate the feasibility of building a photovoltaic cell using dye-sensitized titania and electrolyte on a metal wire core. The approach taken was based on the sequential coating processes used in making fiber optics, namely, a fiber core, e.g., a metal wire serving as the primary electrode, is passed through a series of vertically aligned coating cups. Each of the cups contains a coating fluid that has a specific function in the photocell. A second wire, used as the counter electrode, is brought into the process prior to entering the final coating cup. The latter contains a photopolymerizable, transparent cladding which hardens when passed through a UV chamber. Upon exiting the UV chamber, the finished PV fiber is spooled. Two hundred of foot lengths of PV fiber have been made using this process. When the fiber is exposed to visible radiation, it generates electrical power. The best efficiency exhibited by these fibers is 6% with an average value in the 4

  11. Realization of high efficiency inverted polymer photovoltaic cells for roll-to-roll application

    NASA Astrophysics Data System (ADS)

    So, Franky

    2012-09-01

    Recent progress on solution processable polymeric photovoltaic (PV) cells has drawn a lot of attention in both industry and academia. Over 8% power conversion efficiencies (PCE) have been demonstrated. In order to realize the application of organic PV, high efficiency (~10%) is not the only criteria, but also the low material and processing costs and device stability. For mostly demonstrated laboratory high efficiency cells, the devices consists of high work-function bottom anode and low work-function top cathode, e.g. Al, which is well known that the oxidation of the cathode accelerates the device degradation. In order to accommodate the issue, recent effort has been focusing on developing inverted structure. In such case, the low work-function metal can be eliminated by using a composite electrode with a work-function modifying interlayer. Solution derived TiOx and ZnO nano-particles are widely used as the interlayer. It has been shown such interlayer can efficiently reduce the work-function of bottom ITO electrode and significantly improve the device stability. However, it is often found that the inverted cells processed a lower performance than their counterpart with conventional structure. Such low efficiency is caused by the surface trap states of the nanoparticles which introduce charge recombination.

  12. Rhodanine dyes for dye-sensitized solar cells : spectroscopy, energy levels and photovoltaic performance.

    PubMed

    Marinado, Tannia; Hagberg, Daniel P; Hedlund, Maria; Edvinsson, Tomas; Johansson, Erik M J; Boschloo, Gerrit; Rensmo, Håkan; Brinck, Tore; Sun, Licheng; Hagfeldt, Anders

    2009-01-07

    Three new sensitizers for photoelectrochemical solar cells were synthesized consisting of a triphenylamine donor, a rhodanine-3-acetic acid acceptor and a polyene connection. The conjugation length was systematically increased, which resulted in two effects: first, it led to a red-shift of the optical absorption of the dyes, resulting in an improved spectral overlap with the solar spectrum. Secondly, the oxidation potential decreased systematically. The excited state levels were, however, calculated to be nearly stationary. The experimental trends were in excellent agreement with density functional theory (DFT) computations. The photovoltaic performance of this set of dyes as sensitizers in mesoporous TiO2 solar cells was investigated using electrolytes containing the iodide/triiodide redox couple. The dye with the best absorption characteristics showed the poorest solar cell efficiency, due to losses by recombination of electrons in TiO2 with triiodide. Addition of 4-tert butylpyridine to the electrolyte led to a strongly reduced photocurrent for all dyes due to a reduced electron injection efficiency, caused by a 0.15 V negative shift of the TiO2 conduction band potential.

  13. Candidate solar cell materials for photovoltaic conversion in a solar power satellite /SPS/

    NASA Technical Reports Server (NTRS)

    Glaser, P. E.; Almgren, D. W.

    1978-01-01

    In recognition of the obstacles to solar-generated baseload power on earth, proposals have been made to locate solar power satellites in geosynchronous earth orbit (GEO), where solar energy would be available 24 hours a day during most of the time of the year. In an SPS, the electricity produced by solar energy conversion will be fed to microwave generators forming part of a planar phase-array transmitting antenna. The antenna is designed to precisely direct a microwave beam of very low intensity to one or more receiving antennas at desired locations on earth. At the receiving antenna, the microwave energy will be safely and efficiently reconverted to electricity and then be transmitted to consumers. An SPS system will include a number of satellites in GEO. Attention is given to the photovoltaic option for solar energy conversion in GEO, solar cell requirements, the availability of materials, the implication of large production volumes, requirements for high-volume manufacture of solar cell arrays, and the effects of concentration ratio on solar cell array area.

  14. Investigation of the effect of beta source and phosphors on photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Yürük, Reyyan Kavak; Tütüncüler, Hayriye

    2017-02-01

    In this study, conversion of kinetic energy from the decay of a radioactive isotope to electricity is investigated by using the direct and the indirect conversion methods. In this context, simple nuclear battery models are designed. Analysis for the effect of low-activity radiation from Pm147 and Sr90 beta sources on photovoltaic Si solar cell is presented. Beta radioluminescence nuclear battery models consist of a beta source, a phosphor layer and a solar cell. Phosphor layers with different mass thicknesses are prepared from ZnS:CuCl and SrAl2O4:Eu2+,Dy3+ phosphors. Both the influence of beta sources and the phosphor layers on battery performance is analyzed separately. Effect of beta sources, phosphors are observed on solar cell by measuring the short circuit current and open circuit voltage. The efficiency of the battery models is determined with the obtained results. Furthermore, short circuit current values are analyzed at various times during the irradiation.

  15. Effect of particle size of Martian dust on the degradation of photovoltaic cell performance

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Perez-Davis, Marla E.

    1991-01-01

    Glass coverglass and SiO2 covered and uncovered silicon photovoltaic (PV) cells were subjected to conditions simulating a Mars dust storm, using the Martian Surface Wind Tunnel, to assess the effect of particle size on the performance of PV cells in the Martian environment. The dust used was an artificial mineral of the approximate elemental composition of Martian soil, which was sorted into four different size ranges. Samples were tested both initially clean and initially dusted. The samples were exposed to clear and dust laden winds, wind velocities varying from 23 to 116 m/s, and attack angles from 0 to 90 deg. It was found that transmittance through the coverglass approximates the power produced by a dusty PV cell. Occultation by the dust was found to dominate the performance degradation for wind velocities below 50 m/s, whereas abrasion dominates the degradation at wind velocities above 85 m/s. Occultation is most severe at 0 deg (parallel to the wind), is less pronounced from 22.5 to 67.5 deg, and is somewhat larger at 90 deg (perpendicular to the wind). Abrasion is negligible at 0 deg, and increases to a maximum at 90 deg. Occultation is more of a problem with small particles, whereas large particles (unless they are agglomerates) cause more abrasion.

  16. Optical spacing effect in organic photovoltaic cells incorporating a dilute acceptor layer

    SciTech Connect

    Menke, S. Matthew; Lindsay, Christopher D.; Holmes, Russell J.

    2014-06-16

    The addition of spacing layers in organic photovoltaic cells (OPVs) can enhance light absorption by optimizing the spatial distribution of the incident optical field in the multilayer structure. We explore the optical spacing effect in OPVs achieved using a diluted electron acceptor layer of C{sub 60}. While optical spacing is often realized by optimizing buffer layer thickness, we find that optical spacing via dilution leads to cells with similar or enhanced photocurrent. This is observed despite a smaller quantity of absorbing molecules, suggesting a more efficient use of absorbed photons. In fact, dilution is found to concentrate optical absorption near the electron donor-acceptor interface, resulting in a marked increase in the exciton diffusion efficiency. Contrasting the use of changes in thickness to engineer optical absorption, the use of dilution does not significantly alter the overall thickness of the OPV. Optical spacing via dilution is shown to be a viable alternative to more traditional optical spacing techniques and may be especially useful in the continued optimization of next-generation, tandem OPVs where it is important to minimize competition for optical absorption between individual sub-cells.

  17. Ultra-high efficiency photovoltaic cells for large scale solar power generation.

    PubMed

    Nakano, Yoshiaki

    2012-01-01

    The primary targets of our project are to drastically improve the photovoltaic conversion efficiency and to develop new energy storage and delivery technologies. Our approach to obtain an efficiency over 40% starts from the improvement of III-V multi-junction solar cells by introducing a novel material for each cell realizing an ideal combination of bandgaps and lattice-matching. Further improvement incorporates quantum structures such as stacked quantum wells and quantum dots, which allow higher degree of freedom in the design of the bandgap and the lattice strain. Highly controlled arrangement of either quantum dots or quantum wells permits the coupling of the wavefunctions, and thus forms intermediate bands in the bandgap of a host material, which allows multiple photon absorption theoretically leading to a conversion efficiency exceeding 50%. In addition to such improvements, microfabrication technology for the integrated high-efficiency cells and the development of novel material systems that realizes high efficiency and low cost at the same time are investigated.

  18. Cuprous oxide photovoltaic cells. Third quarterly technical progress report, October 9, 1979 to January 8, 1980

    SciTech Connect

    Trivich, D.

    1980-01-08

    Previous work in this laboratory on cuprous oxide Schottky barrier photovoltaic cells showed that some potential improvements were limited by chemical degradations at the junction (1), e.g., in Al/Cu/sub 2/O cells, the aluminum reduced the surface of the Cu/sub 2/O to metallic Cu. The present project is being devoted to a study of methods to avoid this problem and also to the development of other methods of improving the efficiency of Cu/sub 2/O cells. The first quarterly report was devoted to a study of thin oxide interlayers between the metal and the Cu/sub 2/O which gives MIS structures. The most stable interlayers were obtained with SiO/sub 2/. The second quarterly report covered some initial work on heterojunctions with other oxides on Cu/sub 2/O. The most stable heterojunctions were obtained with CdO on Cu/sub 2/O. The present report presents some results on Auger studies of the oxide heterojunctions, the preparation of doped Cu/sub 2/O by introduction of impurities in the starting copper, the exploration of several method for the study of diffusion length, and some initial attempts on the laser annealing of Cu/sub 2/O.

  19. Required Equipment for Photo-Switchable Donor-Acceptor (D-A) Dyad Interfacial Self-Assembled Monolayers for Organic Photovoltaic Cells

    DTIC Science & Technology

    2014-01-24

    Effects on interfacial morphology and charge injection in organic light-emitting diodes. Thin Solid Films 2007, 515 (5), 2833-2841. 3. Lee, J.; Jung...HBCU) - Required Equipment for Photo-switchable Donor- Acceptor (D-A) Dyad Interfacial Self-Assembled Monolayers for Organic Photovoltaic Cells...Equipment for Photo-switchable Donor-Acceptor (D-A) Dyad Interfacial Self-Assembled Monolayers for Organic Photovoltaic Cells" N/A FA9550-12-1-0468 CFDA

  20. Organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Demming, Anna; Krebs, Frederik C.; Chen, Hongzheng

    2013-12-01

    Energy inflation, the constant encouragement to economize on energy consumption and the huge investments in developing alternative energy resources might seem to suggest that there is a global shortage of energy. Far from it, the energy the Sun beams on the Earth each hour is equivalent to a year's supply, even at our increasingly ravenous rate of global energy consumption [1]. But it's not what you have got it's what you do with it. Hence the intense focus on photovoltaic research to find more efficient ways to harness energy from the Sun. Recently much of this research has centred on organic solar cells since they offer simple, low-cost, light-weight and large-area flexible photovoltaic structures. This issue with guest editors Frederik C Krebs and Hongzheng Chen focuses on some of the developments at the frontier of organic photovoltaic technology. Improving the power conversion efficiency of organic photovoltaic systems, while maintaining the inherent material, economic and fabrication benefits, has absorbed a great deal of research attention in recent years. Here significant progress has been made with reports now of organic photovoltaic devices with efficiencies of around 10%. Yet operating effectively across the electromagnetic spectrum remains a challenge. 'The trend is towards engineering low bandgap polymers with a wide optical absorption range and efficient hole/electron transport materials, so that light harvesting in the red and infrared region is enhanced and as much light of the solar spectrum as possible can be converted into an electrical current', explains Mukundan Thelakkat and colleagues in Germany, the US and UK. In this special issue they report on how charge carrier mobility and morphology of the active blend layer in thin film organic solar cells correlate with device parameters [2]. The work contributes to a better understanding of the solar-cell characteristics of polymer:fullerene blends, which form the material basis for some of the most