Download or read book High Efficiency Polycrystalline CdTe Thin Film Solar Cells with an Oxygenated Amorphous CdS a CdS O Window Layer Preprint written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the conventional CdS/CdTe device structure, the poly-CdS window layer has a bandgap of~2.4 eV, which causes absorption in the short-wavelength region. Higher short-circuit current densities (Jsc) can be achieved by reducing the CdS thickness, but this can adversely impact device open-circuit voltage (Voc) and fill factor (FF). Also, poly-CdS film has about 10% lattice mismatch related to theCdTe film, which limits the improvement of device Voc and FF. In this paper, we report a novel window material: oxygenated amorphous CdS film (a-CdS:O) prepared at room temperature by rf sputtering. The a-CdS:O film has a higher optical bandgap (2.5-3.1 eV) than the poly-CdS film and an amorphous structure. The preliminary device results have demonstrated that Jsc of the CdTe device can begreatly improved while maintaining higher Voc and FF. We have fabricated a CdTe cell demonstrating an NREL-confirmed Jsc of 25.85 mA/cm2 and a total-area efficiency of 15.4%.
Download or read book High Efficiency Polycrystalline CdTe Thin Film Solar Cells with an Oxygenated Amorphous CdS a CdS written by and published by . This book was released on 2002 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the conventional CdS/CdTe device structure, the poly-CdS window layer has a bandgap of (almost equal to)2.4 eV, which causes absorption in the short-wavelength region. Higher short-circuit current densities (Jsc) can be achieved by reducing the CdS thickness, but this can adversely impact device open-circuit voltage (Voc) and fill factor (FF). Also, poly-CdS film has about 10% lattice mismatch related to the CdTe film, which limits the improvement of device Voc and FF. In this paper, we report a novel window material: oxygenated amorphous CdS film (a-CdS:O) prepared at room temperature by rf sputtering. The a-CdS:O film has a higher optical bandgap (2.5-3.1 eV) than the poly-CdS film and an amorphous structure. The preliminary device results have demonstrated that Jsc of the CdTe device can be greatly improved while maintaining higher Voc and FF. We have fabricated a CdTe cell demonstrating an NREL-confirmed Jsc of 25.85 mA/cm2 and a total-area efficiency of 15.4%.
Download or read book High Efficiency Ultra Thin Cadmium Telluride CdTe Solar Cells written by Nowshad Amin and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin film cadmium telluride absorbers with cadmium sulphide hetero-junction partner are promising candidates for high efficiency low cost solutions of solar energy harvesting devices. These devices have band gaps well-suited for effective absorption of sunlight. Most importantly, the materials used in these devices can be deposited in a variety of industry-friendly ways, so that the cost associated with manufacturing is generally lower than other available technologies. Although poly-crystalline CdS has been found to be the best suited heterojunction partner for CdTe solar cell, the conventional polycrystalline CdS/CdTe cell has few issues that limit device performance. In order to overcome these problems, this study proposes the introduction of poly-CdS to amorphous oxygenated CdS (a-CdS: O) as window layer. The a-CdS: O window material has higher optical band gap (2.5-3.1 eV), better lattice match with CdTe absorber materials and reduced inter-diffusion tendency of CdS and CdTe layers. This book systematically demonstrates the conversion process of poly CdS to a-CdS: O and develops a strategy for the fabrication of suitable a-CdS: O layer to be applied in CdTe solar ce
Download or read book High efficiency Cadmium and Zinc telluride based Thin film Solar Cells written by and published by . This book was released on 1992 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes research into polycrystalline CdTe solar cells grown by metal-organic chemical vapor deposition. Efficiencies of (approximately)10% were achieved using both p-i-n and p-n structures. A pre-heat treatment of CdS/SnO2/glass substrates at 450°C in hydrogen atmosphere prior to the CdTe growth was found to be essential for high performance because this heat treatment reduces oxygen-related defects from the CdS surface. However, this treatment also resulted in a Cd-deficient CdS surface, which may in part limit the CdTe cell efficiency to 10% due to Cd vacancy-related interface defects. Preliminary model calculations suggest that removing these states can increase the cell efficiency from 10% to 13.5%. Photon absorption in the CdS film also limits the cell performance, and eliminating this loss mechanism can result in CdTe efficiencies in excess of 18%. Polycrystalline, 1.7-e, CdZnTe films were also grown for tandem-cell applications. CdZnTe/CdS cells processed using the standard CdTe cell fabrication procedure resulted in 4.4% efficiency, high series resistance, and a band-gap shift to 1.55 eV. The formation of Zn-O at and near the CdZnTe surface is the source of high contact resistance. A saturated dichromate each prior to contact deposition was found to solve the contact resistance problem. The CdCl2 treatment was identified as the cause of the observed band-gap shift due to the preferred formation of ZnCl2. 59 refs.
Download or read book Clean Electricity From Photovoltaics 2nd Edition written by Mary D Archer and published by World Scientific. This book was released on 2014-10-17 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of Clean Electricity from Photovoltaics, first published in 2001, provides an updated account of the underlying science, technology and market prospects for photovoltaics. All areas have advanced considerably in the decade since the first edition was published, which include: multi-crystalline silicon cell efficiencies having made impressive advances, thin-film CdTe cells having established a decisive market presence, and organic photovoltaics holding out the prospect of economical large-scale power production.
Download or read book A Comprehensive Guide to Solar Energy Systems written by Trevor Letcher and published by Academic Press. This book was released on 2018-05-17 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Comprehensive Guide to Solar Energy Systems: With Special Focus on Photovoltaic Systems, the most advanced and research focused text on all aspects of solar energy engineering, is a must have edition on the present state of solar technology, integration and worldwide distribution. In addition, the book provides a high-level assessment of the growth trends in photovoltaics and how investment, planning and economic infrastructure can support those innovations. Each chapter includes a research overview with a detailed analysis and new case studies that look at how recent research developments can be applied. Written by some of the most forward-thinking professionals, this book is an invaluable reference for engineers. - Contains analysis of the latest high-level research and explores real world application potential in relation to developments - Uses system international (SI) units and imperial units throughout to appeal to global engineers - Offers measurable data written by a world expert in the field on the latest developments in this fast moving and vital subject
Download or read book Nanomaterials for Solar Cell Applications written by Sabu Thomas and published by Elsevier. This book was released on 2019-06-12 with total page 761 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanomaterials for Solar Cell Applications provides a review of recent developments in the field of nanomaterials based solar cells. It begins with a discussion of the fundamentals of nanomaterials for solar calls, including a discussion of lifecycle assessments and characterization techniques. Next, it reviews various types of solar cells, i.e., Thin film, Metal-oxide, Nanowire, Nanorod and Nanoporous materials, and more. Other topics covered include a review of quantum dot sensitized and perovskite and polymer nanocomposites-based solar cells. This book is an ideal resource for those working in this evolving field of nanomaterials and renewable energy. - Provides a well-organized approach to the use of nanomaterials for solar cell applications - Discusses the synthesis, characterization and applications of traditional and new material - Includes coverage of emerging nanomaterials, such as graphene, graphene-derivatives and perovskites
Download or read book High efficiency CTO ZTO CdS CdTe Polycrystalline Thin film Solar Cells written by and published by . This book was released on 2001 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of High Efficiency Polycrystalline Cadmium Telluride Cadmium Sulfide Solar Cells Using Electrodeposition written by Wenjie Song and published by . This book was released on 1999 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of High efficiency Thin film CdTe Solar Cells Annual Subcontract Report January 1 1993 December 31 1993 written by and published by . This book was released on 1994 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polycrystalline thin film CdTe solar cells are one of the leading candidates for terrestrial photovoltaic applications. Theoretical calculations project an efficiency of 27% for single crystal, single junction CdTe cells, and the practically achievable efficiency for polycrystalline CdTe cells is 18-20%. Polycrystalline CdTe cells made by different groups show a significant variation in short circuit currents, open circuit voltages, and cell efficiencies. A better understanding of carrier loss and transport mechanism is crucial for explaining these differences, improving the yield, and bridging the gap between current and practically achievable limits in CdTe cell efficiencies. The goal of this program is to improve the understanding of the loss mechanisms in thin film CdS/CdTe solar cells and to improve their efficiency by characterizing the properties of the films as well as the finished devices.
Download or read book Development of High efficiency Thin film CdTe Solar Cells Final Subcontract Report 1 February 1992 30 November 1995 written by and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes work performed by the Georgia Institute of Technology (GIT) to bring the polycrystalline CdTe cell efficiency a step closer to the practically achievable efficiency of 18% through fundamental understanding of detects and loss mechanisms, the role of chemical and heat treatments, and investigation of now process techniques. The objective was addressed by a combination of in-depth characterization, modeling, materials growth, device fabrication, and 'transport analyses of Au/Cu/CdTe/CdS/SnO 2 glass front-wall heterojunction solar cells. GiT attempted to understand the loss mechanism(s) in each layer and interface by a step-by-step investigation of this multilayer cell structure. The first step was to understand, quantify, and reduce the reflectance and photocurrent loss in polycrystalline CdTe solar calls. The second step involved the investigation of detects and loss mechanisms associated with the CdTe layer and the CdTe/CdS interface. The third stop was to investigate the effect of chemical and heat treatments on CdTe films and cells. The fourth step was to achieve a better and reliable contact to CdTe solar cells by improving the fundamental understanding. Of the effects of Cu on cell efficiency. Finally, the research involved the investigation of the effect of crystallinity and grain boundaries on Cu incorporation in the CdTe films, including the fabrication of CdTe solar calls with larger CdTe grain size.
Download or read book High Efficiency Thin Film CdTe and A Si Based Solar Cells written by and published by . This book was released on 2000 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes work done by the University of Toledo during the first year of this subcontract. During this time, the CdTe group constructed a second dual magnetron sputter deposition facility; optimized reactive sputtering for ZnTe:N films to achieve 10 ohm-cm resistivity and (approximately)9% efficiency cells with a copper-free ZnTe:N/Ni contact; identified Cu-related photoluminescence features and studied their correlation with cell performance including their dependence on temperature and E-fields; studied band-tail absorption in CdS(subscript x)Te{sub 1-x} films at 10 K and 300 K; collaborated with the National CdTe PV Team on (1) studies of high-resistivity tin oxide (HRT) layers from ITN Energy Systems, (2) fabrication of cells on the HRT layers with 0, 300, and 800-nm CdS, and (3) preparation of ZnTe:N-based contacts on First Solar materials for stress testing; and collaborated with Brooklyn College for ellipsometry studies of CdS(subscript x)Te{sub 1-x} alloy films, and with the University of Buffalo/Brookhaven NSLS for synchrotron X-ray fluorescence studies of interdiffusion in CdS/CdTe bilayers. The a-Si group established a baseline for fabricating a-Si-based solar cells with single, tandem, and triple-junction structures; fabricated a-Si/a-SiGe/a-SiGe triple-junction solar cells with an initial efficiency of 9.7% during the second quarter, and 10.6% during the fourth quarter (after 1166 hours of light-soaking under 1-sun light intensity at 50 C, the 10.6% solar cells stabilized at about 9%); fabricated wide-bandgap a-Si top cells, the highest Voc achieved for the single-junction top cell was 1.02 V, and top cells with high FF (up to 74%) were fabricated routinely; fabricated high-quality narrow-bandgap a-SiGe solar cells with 8.3% efficiency; found that bandgap-graded buffer layers improve the performance (Voc and FF) of the narrow-bandgap a-SiGe bottom cells; and found that a small amount of oxygen partial pressure ((approximately)2 x 10−5 torr) was beneficial for growing high-quality films from ITO targets.
Download or read book CdS CdTe Thin film Solar Cell with a Zinc Stannate Buffer Layer written by Xuanzhi Wu and published by . This book was released on 1998 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrical Characterization of Electrodeposited N CdS p CdTe Polycrystalline Thin film Solar Cells written by Roshanak Hakimzadeh and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Processing and Characterization of High Efficiency CdS CdTe Thin Film Solar Cells on Low Cost Substrates written by Bhaskar Reddy Tetali and published by . This book was released on 1996 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Compound Semiconductor Photovoltaics written by Materials Research Society. Meeting and published by . This book was released on 2003 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume focuses on basic and applied materials research related to compound semiconductors. Emphasis is on materials that are used, or have clear potential use, as thin films in solar cells and spin-off applications. Relevant materials include Cu(In, Ga, Al)(Se, S)2, MX (M = Zn and/or Cd; X = S, Se and/or Te), III-V photovoltaic materials, and transparent conducting oxides. Understanding fundamental materials limitations, real or perceived, are of particular interest. Highlights center on: materials-related prerequisites for high-efficiency thin-film solar cells; the dynamics of chemical treatment/etching of CdTe with emphasis on back contacting; high-resolution microanalysis of grain boundaries and surface chemistry and how they affect device performance; the role and significance of transparent conducting oxides in device performance; and the electronic structure of highly mismatched III-V alloy semiconductors.
Download or read book Thin Film Solar Cells written by K. L. Chopra and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 615 pages. Available in PDF, EPUB and Kindle. Book excerpt: "You, 0 Sun, are the eye of the world You are the soul of all embodied beings You are the source of all creatures You are the discipline of all engaged in work" - Translated from Mahabharata 3rd Century BC Today, energy is the lifeline and status symbol of "civilized" societies. All nations have therefore embarked upon Research and Development pro grams of varying magnitudes to explore and effectively utilize renewable sources of energy. Albeit a low-grade energy with large temporal and spatial variations, solar energy is abundant, cheap, clean, and renewable, and thus presents a very attractive alternative source. The direct conver sion of solar energy to electricity (photovoltaic effect) via devices called solar cells has already become an established frontier area of science and technology. Born out of necessity for remote area applications, the first commercially manufactured solar cells - single-crystal silicon and thin film CdS/Cu2S - were available well over 20 years ago. Indeed, all space vehicles today are powered by silicon solar cells. But large-scale terrestrial applications of solar cells still await major breakthroughs in terms of discovering new and radical concepts in solar cell device structures, utilizing relatively more abundant, cheap, and even exotic materials, and inventing simpler and less energy intensive fabrication processes. No doubt, this extraordinary challenge in R/D has led to a virtual explosion of activities in the field of photovoltaics in the last several years.
