Download or read book CdS CdTe Thin film Solar Cell with a Zinc Stannate Buffer Layer written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cds cdte Thin Film Solar Cells with Zinc Stannate Buffer Layer written by Srilatha Bapanapalli and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: CdS/CdTe solar cell performance and reproducibility can be improved by integrating a ZTO buffer layer, which interdiffuses into the CdS layer during device fabrication. Reducing the thickness of CdS layer improves the QE in the blue spectral region without affecting the device performance. This buffer layer is expected to prevent the formation of localized TCO/CdTe junction during high temperature processing. The CdS/CdTe Solar Cell was modified by introducing ZTO as a buffer layer between the window layer (CdS) and the absorber layer (CdTe). Studies were performed on different varying ZTO processing parameters like (a) Zn/Sn atomic ratios during sputtering process, (b) ZTO thickness, (c) ZTO heat treatment temperature, and (d) ZTO heat treatment ambient.
Download or read book High Resistivity Zinc Stannate as a Buffer Layer in Cds cdte Solar Cells written by Sudhakar. R. Gayam and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of stoichiometry on structure, optical and electrical properties of Cd2SnO4 is studied by varying the amount of CdO and SnO2 in the Cd2SnO4 film. Zinc stannate thin films are deposited by co-sputtering of ZnO and SnO2 targets in Ar ambient at both room temperature and elevated temperatures. As deposited and high temperature annealed Zn2SnO4 thin films are highly resistive. The average transmission of a Zn2SnO4 thin film with a thickness of 2000[angstrom] and annealed at 600ʻC in He has been 94%. Zn2SnO4 thin films are incorporated as a buffer layers into CdTe solar cells. SnO2: F is used as a front contact in CdTe solar cells in conjunction with high resistive Zn2SnO4 buffer layer. The best SnO2:F /zinc stannate cell device performance for room temperature deposited zinc stannate film resulted for the device with Zn/Sn =2.1. It has an efficiency of 12.43% with VOC = 810mV, FF = 66.6% and JSC = 23.1 mA.
Download or read book Spartakiada 1952 written by and published by . This book was released on 1953 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Processing of CdTe and CuIn subscript 1 x Ga subscript x Se2 Based Solar Cells Final Technical Report 26 May 1998 22 December 2001 written by Don Louis Morel and published by DIANE Publishing. This book was released on 2003 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Composite Materials for Medicine and Nanotechnology written by Brahim Attaf and published by BoD – Books on Demand. This book was released on 2011-04-01 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to their good mechanical characteristics in terms of stiffness and strength coupled with mass-saving advantage and other attractive physico-chemical properties, composite materials are successfully used in medicine and nanotechnology fields. To this end, the chapters composing the book have been divided into the following sections: medicine, dental and pharmaceutical applications; nanocomposites for energy efficiency; characterization and fabrication, all of which provide an invaluable overview of this fascinating subject area. The book presents, in addition, some studies carried out in orthopedic and stomatological applications and others aiming to design and produce new devices using the latest advances in nanotechnology. This wide variety of theoretical, numerical and experimental results can help specialists involved in these disciplines to enhance competitiveness and innovation.
Download or read book Influence of a Front Buffer Layer on the Performance of Flexible CdS CdTe Solar Cells written by Hasitha Padmika Mahabaduge and published by . This book was released on 2013 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cadmium telluride (CdTe) solar cells have been developing as a promising candidate for large-scale application of photovoltaic energy conversion and have become the most commercially successful polycrystalline thin-film solar module material. In scaling up from small cells to large-area modules, inevitably non-uniformities across the large area will limit the performance of the large cell or module. The effects of these non-uniformities can be reduced by introducing a thin, high-resistivity transparent buffer layer between the conductive electrodes and the semiconductor diode. ZnO is explored in this dissertation as a high-resistivity transparent buffer layer for sputtered CdTe solar cells and efficiencies over 15% have been achieved on commercially available Pilkington TEC15M glass substrates. The highest open-circuit voltage of 0.858V achieved using the optimized ZnO buffer layer is among the best reported in the literature. The properties of ZnO:Al as a buffer are also investigated. We have shown that ZnO:Al can serve both as a transparent conducting oxide layer as well as a high-resistivity transparent layer for CdTe solar cells. ZnO:Al reactively sputtered with oxygen can give the necessary resistivities that allow it to be used as a high-resistivity transparent layer. Glass is the most common choice as the substrate for solar cells fabricated in the superstrate configuration due to its transparency and mechanical rigidity. However flexible substrates offer the advantages of light weight, high flexibility, ease of integrability and higher throughput through roll-to-roll processing over glass. This dissertation presents significant improvements made to flexible CdTe solar cells reporting an efficiency of 14% on clear Kapton® flexible polyimide substrates. Our efficiency of 14% is, to our knowledge, the best for any flexible CdTe cell reported in literature.
Download or read book Development of Back Contacts for CdTe Thin Films Solar Cells written by Fadhil Khalaf Dahash Alfadhili and published by . This book was released on 2020 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin film solar cells based on polycrystalline p-type cadmium telluride (CdTe) represent one of these the most promising photovoltaic (PV) device due to high efficiency and low-cost production. Currently, CdTe solar cells provide the lowest cost electricity generation in utility-scale applications, which is a cost-competitive with the traditional power source, fossil fuel. CdTe thin film PV has attained 22.1 % of power conversion efficiency for small area scale and 18.6 % for modules scale. However, the high efficiency of CdTe devices has been achieved by increasing the photo-generated current by changing the traditional window layer (CdS) of CdTe to a wider bandgap material with better band alignment. The open-circuit voltage (VOC) remains below the theoretical limit due to a barrier at the back of the device due to the deep valence band edge of CdTe (-5.9 eV). Voc can be increased by adding a buffer layer between CdTe and the back electrode to decrease band banding and reducing carrier recombination at the back interface. In this thesis, several materials were investigated as a back-buffer layer, such as single-wall carbon nanotube (SWCNT), zinc telluride (ZnTe), tellurium (Te), and cadmium zinc telluride (CZT) to minimize the bend bending at CdTe/back-buffer layer interface. An alternative method to reduce the carrier recombination at the rear surface, the use of aluminum oxide (Al2O3) layer as a passivation layer was also demonstrated. Finally, an effective method of CdCl2 treatment for CZT thin film was investigated. This method shows that zinc (Zn) can be maintained during the heat treatment.
Download or read book Green Sustainable Process for Chemical and Environmental Engineering and Science written by Rajender Boddula and published by Elsevier. This book was released on 2021-03-18 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Green Sustainable Process for Chemical and Environmental Engineering and Science: Solid State Synthetic Methods cover recent advances made in the field of solid-state materials synthesis and its various applications. The book provides a brief introduction to the topic and the fundamental principles governing the various methods. Sustainable techniques and green processes development in solid-state chemistry are also highlighted. This book also provides a comprehensive literature on the industrial application using solid-state materials and solid-state devices. Overall, this book is intended to explore green solid-state techniques, eco-friendly materials involved in organic synthesis and real-time applications. - Provides a broad overview of solid-state chemistry - Outlines an eco-friendly solid-state synthesis of modern nanomaterials, organometallic, coordination compounds and pure organic - Gives a detailed account of solid-state chemistry, fundamentals, concepts, techniques and applications - Deliberates cutting-edge recent advances in industrial technologies involved in energy, environmental, medicinal and organic chemistry fields
Download or read book Organic Nanostructured Thin Film Devices and Coatings for Clean Energy written by Sam Zhang and published by CRC Press. This book was released on 2010-06-18 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Authored by leading experts from around the world, the three-volume Handbook of Nanostructured Thin Films and Coatings gives scientific researchers and product engineers a resource as dynamic and flexible as the field itself. The first two volumes cover the latest research and application of the mechanical and functional properties of thin films an
Download or read book Copper Zinc Tin Sulfide Based Thin Film Solar Cells written by Kentaro Ito and published by John Wiley & Sons. This book was released on 2014-12-11 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beginning with an overview and historical background of Copper Zinc Tin Sulphide (CZTS) technology, subsequent chapters cover properties of CZTS thin films, different preparation methods of CZTS thin films, a comparative study of CZTS and CIGS solar cell, computational approach, and future applications of CZTS thin film solar modules to both ground-mount and rooftop installation. The semiconducting compound (CZTS) is made up earth-abundant, low-cost and non-toxic elements, which make it an ideal candidate to replace Cu(In,Ga)Se2 (CIGS) and CdTe solar cells which face material scarcity and toxicity issues. The device performance of CZTS-based thin film solar cells has been steadily improving over the past 20 years, and they have now reached near commercial efficiency levels (10%). These achievements prove that CZTS-based solar cells have the potential to be used for large-scale deployment of photovoltaics. With contributions from leading researchers from academia and industry, many of these authors have contributed to the improvement of its efficiency, and have rich experience in preparing a variety of semiconducting thin films for solar cells.
Download or read book Approaches to Fabricating High efficiency Ultra thin CdTe Solar Cells written by Wei Xia and published by . This book was released on 2012 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This thesis is an investigation of the fabrication, characterization and performance of high-efficiency and ultra-thin CdTe solar cells with an aim of reducing the material usage and cell manufacturing cost. Several approaches have been successfully carried out to directly or indirectly improve the device performance. Major achievements are listed below: 1) A close-spaced sublimation (CSS) process with an improved control of the deposition temperature-time profile was developed to fabricate high-quality ultra-thin CdTe films. Three key factors in the CSS process including oxygen pressure, substrate temperature and thermal etch duration were optimized. 2) A two-stage post-deposition treatment including a high temperature annealing (HTA) followed by a vaporous cadmium chloride treatment (VCC) was developed and optimized for the growth of high-quality CdTe films. The effects of HTA and VCC on ultra-thin CdTe solar cells were revealed by a combination of characterization techniques, including photoluminescence. 3) In a collaborative effort two new back contact buffers, MoOx and Te/Cu, were identified and applied in ultra-thin CdTe solar cells. Substitution of a conventional acid etching method with the new back contact buffers was found to enhance the cell efficiency from ~10% to ~13.5%. Moreover, the new buffers improved the reproducibility of cell fabrication. A low-resistance electrical back contact based on the Te/Cu buffer and Ni as electrode was developed. A thermal activation process was found necessary to promote ohmic contact formation. Cu diffusion into the Te layer and CdTe bulk layer occurred during the thermal activation process and must be controlled to prevent excessive diffusion into the CdS/CdTe junction. The effects of Cu concentration and Te thickness on device performance and cell stability were systematically investigated and a cell efficiency as high as ~15% with good stability has been achieved using an optimized Te/Cu buffer. 4) A novel vaporous zinc chloride treatment was developed for the formation of Cd1xZnxS from CdS films. Compared with conventional fabrication methods, the VZC method features simple setup and operation and is capable of producing Cd1xZnxS films with a homogenous structure. The Zn to Cd doping ratio in Cd1−xZnxS can be easily controlled by adjusting the process parameters. By replacing CdS with a more transparent Cd1−xZnxS as the window layer, CdTe solar cells with a higher (12-14%) short-circuit current, Jsc, have been demonstrated"--Page v-vi.
Download or read book Indium Oxide as a High Resistivity Buffer Layer for CdTe CdS Thin Film Solar Cells written by Umamaheswari Balasubramanian and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: ITO films with resistivity as low as 1.9X10-4 ohm-cm, mobility 32 cm2V-1s-1 and average transmission %7E 90% in the visible region were obtained for carrier concentration in the order of 1.1XE21cm-3.
Download or read book CdTe CdS Thin Film Solar Cells Fabricated on Flexible Substrates written by Vasilios Palekis and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Cadmium Telluride (CdTe) is a leading thin film photovoltaic (PV) material due to its near ideal bandgap of 1.45 eV and its high optical absorption coefficient. The typical CdTe thin film solar cell is of the superstrate configuration where a window layer (CdS), the absorber (CdTe) and a back contact are deposited onto glass coated with a transparent electrode. Substrate CdTe solar cells where the above listed films are deposited in reverse are not common. In this study substrate CdTe solar cells are fabricated on flexible foils. The properties of the Molybdenum back contact, Zinc Telluride (ZnTe) interlayer and CdTe absorber on the flexible foils were studied and characterized using X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). Substrate curvature and film flaking was observed during the fabrication as a result of differences in thermal expansion coefficients between the substrate and the deposited films, and also due to impurity diffusion from the foil into the film stack. In order to overcome this problem diffusion barriers where used to eliminate contamination. Silicon dioxide (SiO2), silicon nitride (Si3N4) and molybdenum nitride (MoxNy) were used as such barriers. Electrical characterization of completed devices was carried out by Current-Voltage (J-V), Capacitance-Voltage (C-V) and Spectral Response (SR) measurements. Roll-over was observed in the first quadrant of J-V curves indicating the existence of a back barrier due to a Schottky back contact. The formation of non-rectifying contact to p-CdTe thin-film is one of the major and critical challenges associated with the fabrication of efficient and stable solar cells. Several materials (ZnTe, Cu, Cu2Te, and Te) were studied as potential candidates for the formation of an effective back contact.
Download or read book NCPV Photovoltaics Program Review written by National Center for Photovoltaics (U.S.) and published by American Institute of Physics. This book was released on 1999-03-12 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceedings volume compiles 123 papers that were presented orally or as posters at the National Center for Photovoltaics (NCPV) Program Review Meeting, held in Denver, Colorado, on September 8-11, 1998. The purpose of this meeting was to highlight the advances made in various areas of photovoltaics by and through the NCPV during the period of December 1997 to September 1998. Topics covered ranged from research in crystalline silicon and thin-film technologies, to manufacturing of photovoltaic modules, to applications of and markets for photovoltaic products.
Download or read book Photovoltaic Energy Program Contract Summary Fiscal Year 2000 written by and published by DIANE Publishing. This book was released on 2001 with total page 335 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of Molybdenum Oxide as a Back Contact Buffer for Thin Film N CdS p CdTe Solar Cells written by Hao Lin and published by . This book was released on 2012 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Back contact improvement is one of the most crucial issues for the realization of highly efficient n-CdS/p-CdTe solar cells. Conventional methods for making a sufficiently ohmic contact to p-CdTe usually involve a solution etching process and a Cu doping process, which are known to negatively affect the device reliability. To resolve this problem, a low-resistance back contact for n-CdS/p-CdTe solar cells has been developed, which utilizes a vapor-deposited transition metal oxide (TMO) thin film as the back contact buffer layer between p-CdTe and the back electrode. The usefulness of TMO is attributed to its unusually high work function which is needed to match that of p-type CdTe in producing a contact of low resistance. As one major representative of TMO materials, molybdenum oxide (MoOx) has been investigated as a novel buffer in this thesis. First, the processes for making low resistance contact with MoOx buffer are explored. To achieve a good ohmic contact to p-CdTe, a water rinse step is necessary in order to remove surface residues from the CdTe surface prior to MoOx deposition. In addition, different methods for depositing MoOx films have been examined, including thermal evaporation and DC sputtering methods. With MoOx as the high work function buffer, various metals can be used as the electrode to realize an ohmic back contact to p-CdTe. Other advantages of the MoOx buffer include dry application by vacuum deposition, and thus it is particularly suitable for the fabrication of ultra-thin CdTe solar cells without introducing additional shorting defects. Second, the mechanism by which MoOx improves the performance of the back contact is studied through the investigation of Ni/CdTe and Ni/MoOx/CdTe interfaces with x-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Contrasting differences in the interface formation and core level structure were observed, indicating that the presence of a thin MoOx inter-layer was effective in reducing the unfavorable reaction between Ni and the native tellurium oxide at the CdTe surface. Finally, the stability of CdTe cells with MoOx buffer is studied. MoOx is found to effectively stabilize the device performance, especially the open-circuit voltage (Voc) of the CdTe solar cell during thermal stress tests. The cell with a Ni-only electrode rapidly degrades due to Ni diffusing into the CdTe film and Ni abstracting Te from CdTe. With the addition of a layer of MoOx as the buffer layer, the diffusion of Ni and the reaction between Ni and CdTe are alleviated, resulting in significantly improved device stability. To summarize, an efficient and stable back contact has been developed through the application of a high work function MoOx as the buffer for p-CdTe. As a result, n-CdS/p-CdTe solar cells with improved efficiency and stability have been realized"--Page viii-ix.
