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 Development of CdTe Thin Film Solar Cells on Flexible Foil Substrates written by Deidra Ranel Hodges and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Cadmium telluride (CdTe) is a leading thin film photovoltaic (PV) material due to its near ideal band gap of 1.45 eV, its high optical absorption coefficient and availability of various device fabrication methods. Superstrate CdTe solar cells fabricated on glass have to-date exhibited efficiencies of 16.5%. Work on substrate devices has been limited due to difficulties associated with the formation of an ohmic back contact with CdTe. The most promising approach used to-date is based on the use of an interlayer between the CdTe and a metal electrode, an approach that is believed to yield a pseudo-ohmic contact. This research investigates the use of ZnTe and Sb2Te3 as the interlayer, in the development of efficient back contacts. Excellent adhesion and minimum stress are also required of a CdTe thin film solar cell device on a flexible stainless steel (SS) foil substrate. Foil substrate curvature, flaking, delamination and adhesion as a result of compressive strain due to the coefficient of thermal expansion (CTE) mismatch between the flexible SS foil substrate and the solar cell films have been studied. A potential problem with the use of a SS foil as the substrate is the diffusion of iron (Fe), chromium (Cr) and other elemental impurities into the layers of the solar cell device structure during high temperature processing. A diffusion barrier limiting the out diffusion of these substrate elements is being investigated in this study. Silicon nitride (Si3N4) films deposited on SS foils are being investigated as the barrier layer, to reduce or inhibit the diffusion of substrate impurities into the solar cell. Thin film CdTe solar cells have been fabricated and characterized by AFM, XRD, SEM, ASTM D3359-08 tape test, current-voltage (I-V) and spectral measurements. My individual contributions to this work include the Molybdenum (Mo) development, the adhesion studies, the silicon nitride (Si3N4) barrier studies, and EDS and SEM lines measurements and analysis of substrate out-diffused impurities. The rest of my colleagues focused on the development of CdTe, CdS, ZnTe, the CdCl2 heat treatment, and other back contact interlayer materials.
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.
Download or read book Fundamentals Of Solar Cells written by Alan Fahrenbruch and published by Elsevier. This book was released on 2012-12-02 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Solar Cells: Photovoltaic Solar Energy Conversion provides an introduction to the fundamental physical principles of solar cells. It aims to promote the expansion of solar photovoltaics from relatively small and specialized use to a large-scale contribution to energy supply. The book begins with a review of basic concepts such as the source of energy, the role of photovoltaic conversion, the development of photovoltaic cells, and sequence of phenomena involved in solar power generation. This is followed by separate chapters on each of the processes that take place in solar cell. These include solar input; properties of semiconductors; recombination and the flow of photogenerated carriers; charge separation and the characteristics of junction barriers; and calculation of solar efficiency. Subsequent chapters deal with the operation of specific solar cell devices such as a single-crystal homojunction (Si); a single-crystal-heterojunction/buried-homojunction (AlGaAs/GaAs); and a polycrystalline, thin-film cell (CuxS/CdS). This book is intended for upper-level graduate students who have a reasonably good understanding of solid state physics and for scientists and engineers involved in research and development of solar cells.
Download or read book Coatings and Thin Film Technologies written by Jaime Andres Perez Taborda and published by BoD – Books on Demand. This book was released on 2019-01-03 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of coatings and thin-film technologies is rapidly advancing to keep up with new uses for semiconductor, optical, tribological, thermoelectric, solar, security, and smart sensing applications, among others. In this sense, thin-film coatings and structures are increasingly sophisticated with more specific properties, new geometries, large areas, the use of heterogeneous materials and flexible and rigid coating substrates to produce thin-film structures with improved performance and properties in response to new challenges that the industry presents. This book aims to provide the reader with a complete overview of the current state of applications and developments in thin-film technology, discussing applications, health and safety in thin films, and presenting reviews and experimental results of recognized experts in the area of coatings and thin-film technologies.
Download or read book Solar Cells and Modules written by Arvind Shah and published by Springer Nature. This book was released on 2020-07-16 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives a comprehensive introduction to the field of photovoltaic (PV) solar cells and modules. In thirteen chapters, it addresses a wide range of topics including the spectrum of light received by PV devices, the basic functioning of a solar cell, and the physical factors limiting the efficiency of solar cells. It places particular emphasis on crystalline silicon solar cells and modules, which constitute today more than 90 % of all modules sold worldwide. Describing in great detail both the manufacturing process and resulting module performance, the book also touches on the newest developments in this sector, such as Tunnel Oxide Passivated Contact (TOPCON) and heterojunction modules, while dedicating a major chapter to general questions of module design and fabrication. Overall, it presents the essential theoretical and practical concepts of PV solar cells and modules in an easy-to-understand manner and discusses current challenges facing the global research and development community.
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 Thin Film Solar Cells written by Jef Poortmans and published by John Wiley & Sons. This book was released on 2006-10-16 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin-film solar cells are either emerging or about to emerge from the research laboratory to become commercially available devices finding practical various applications. Currently no textbook outlining the basic theoretical background, methods of fabrication and applications currently exist. Thus, this book aims to present for the first time an in-depth overview of this topic covering a broad range of thin-film solar cell technologies including both organic and inorganic materials, presented in a systematic fashion, by the scientific leaders in the respective domains. It covers a broad range of related topics, from physical principles to design, fabrication, characterization, and applications of novel photovoltaic devices.
Download or read book Next Generation Multilayer Graded Bandgap Solar Cells written by A. A. Ojo and published by Springer. This book was released on 2018-08-16 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book will guide Photovoltaics researchers in a new way of thinking about harvesting light energy from all wavelengths of the solar spectrum. It closes the gap between general solar cells books and photovoltaics journal articles, by focusing on the latest developments in our understanding of solid-state device physics. The material presented is experimental and based on II-VI thin-film materials, mainly CdTe-based solar cells. The authors describe the use of new device design, based on multilayer graded bandgap configuration, using CdTe-based solar cells. The authors also explain how the photo-generated currents can be enhanced using multi-step charge carrier production. The possibility of fabricating these devices using low-cost and scalable electroplating is demonstrated. The value of electroplating for large area electronic devices such as PV solar panels, display devices and nano-technology devices are also demonstrated. By enabling new understanding of the engineering of electroplated semiconductor materials and providing an overview of the semiconductor physics and technology, this practical book is ideal to guide researchers, engineers, and manufacturers on future solar cell device designs and fabrications. Discusses in detail the processes of growths, treatments, solar cell device fabrication and solid state physics, improving readers’ understanding of fundamental solid state physics; Enables future improvements in CdTe-based device efficiency; Explains the significance of defects in deposited semiconductor materials and interfaces that affect the material properties and resulting device performance.
Download or read book Inorganic Flexible Optoelectronics written by Zhenqiang Ma and published by John Wiley & Sons. This book was released on 2019-04-29 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensively covering inorganic flexible optoelectronics and their applications This highly application-oriented book provides an overview of the vibrant research field of inorganic flexible optoelectronics ? from materials to applications ? covering bulk materials as well as nanowires, thin films, nanomembranes for application in light emitting diodes, photodetectors, phototransistors, and solar cells. Edited and written by world-leading experts in the field, Inorganic Flexible Optoelectronics: Materials and Applications begins by covering flexible inorganic light emitting diodes enabled by new materials and designs, and provides examples of their use in neuroscience research. It then looks at flexible light-emitting diodes based on inorganic semiconductor nanostructures ? from thin films to nanowires. Next, the book examines flexible photodetectors with nanomembranes and nanowires; 2-D material based photodetectors on flexible substrates; and IV group materials based solar cells and their flexible photovoltaic technologies. Following that, it presents readers with a section on thin-film III-V single junction and multijunction solar cells and demonstrates their integration onto heterogeneous substrates. Finally, the book finishes with in-depth coverage of novel materials based flexible solar cells. -A must-have book that provides an unprecedented overview of the state of the art in flexible optoelectronics -Supplies in-depth information for new and already active researchers in the field of optoelectronics -Lays down the undiluted knowledge on inorganic flexible optoelectronics ? from materials to devices -Focuses on materials and devices for high-performance applications such as light-emitting diodes, solar cells, and photodetectors Inorganic Flexible Optoelectronics: Materials and Applications appeals to materials scientists, electronics engineers, electrical engineers, inorganic chemists, and solid state physicists.
Download or read book Low Temperature Grown CdTe Thin Film Solar Cells for the Application on Flexible Substrates written by Julian Christoph Perrenoud and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of CdCl2 Treatment on Physical Properties of CdTe CdS Thin Film Solar Cell written by Nazar Abbas Shah and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report CdTe, CdS, and ITO thin films on glass substrates for solar cell fabrication by closed space sublimation and chemical bath deposition. CdTe and CdS thin films were sublimated to chemical treatment at 25°C in a saturated CdCl2 solution (1.04 g/100 ml methanol) and heat treated at 400°C for 30 minutes. Indium tin oxide and tellurium films were analyzed by spectrophotometer and scanning electron microscopy. It has been observed that solar cell performance can be improved by depositing a CdCl2 layer on the CdTe/CdS layers. The optical, structural, and morphological changes of CdTe and CdS surfaces on CdTe/CdS/ITO/glass solar cells due to CdCl2 solution treatment followed by annealing for 400°C were studied. Optical analysis showed about 15% decrease in transmittance after CdCl2 heat treatment in case of CdTe thin film, whereas CdS thin film demonstrated an increase of about 10-15% transmittance after CdCl2 heat treatment. Similarly, a decrease in band gap values was found for both CdTe and CdS thin films after CdCl2 heat treatment. XRD and SEM results of CdCl2 heat-treated CdTe and CdS samples showed recrystallization, reorientation, and progressive increase in grain size. The grain sizes of CdTe and CdS samples demonstrated an increase of about 0.2 μm.
Download or read book Recent Advances in Thin Film Photovoltaics written by Udai P. Singh and published by Springer Nature. This book was released on 2022-09-02 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides recent development in thin-film solar cells (TFSC). TFSC have proven the promising approach for terrestrial and space photovoltaics. TFSC have the potential to change the device design and produce high efficiency devices on rigid/flexible substrates with significantly low manufacturing cost. TFSC have several advantages in manufacturing compared to traditional crystalline Si-solar cells like less requirement of materials, can be prepared with earth’s abundant materials, less processing steps, easy to dispose, etc. Several universities/research institutes/industry in India and abroad are involved in the research area of thin-film solar cells. The book helps the readers to find the details about different thin-film technologies and its advancement at one place. Each chapter covers properties of materials, its suitability for PV applications, simple manufacturing processes and recent and past literature survey. The issues related to the development of high efficiency TFSC devices over large area and its commercial and future prospects are discussed.
Download or read book Issues in the Development of All sputtered ZnO CdS CdTe Flexible Solar Cells written by Anthony Clark Vasko and published by . This book was released on 2009 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cadmium telluride (CdTe) solar cells are traditionally made on glass in a superstrate configuration, taking advantage of the transparency and mechanical rigidity of glass, as well as the ability to form the back contact last. However, there are advantages to fabricating solar cells on flexible substrates such as plastic sheets. Advantages include high specific powers (power generated per mass of the device) for low weight applications, the possibility for continuous roll-to-roll manufacturing suitable for industry, and the opportunity to place solar devices on objects and structures that are not necessarily flat. We have fabricated various flexible CdTe devices through sputter deposition, using aluminum doped zinc oxide (AZO) as a transparent conducting oxide (TCO) top contact. Early devices, made by naively applying fabrication techniques used with glass cells, had poor performance. This inspired several investigations. Traditional simple heuristic analysis of solar cell current-voltage curves assumes the cell is reasonably performing and that series and shunt resistance losses are small. This was not true for our early cells, inspiring us to derive a simple model for very poor cells. Early cells showed significant losses due to both series and shunt resistance. Series resistance losses in flexible cells inspired us to investigate more deeply series resistance losses in general, resulting in a fairly simple model that relates fill factor losses, in dot cells made in a typical geometry, to TCO sheet resistance. This model was confirmed by experiment. Series resistance losses also led to futher investigation of AZO properties. We have found that AZO sheet resistance increases during cell fabrication, but a model that is supported by experiment indicates that the resistivity change is limited to a finite thickness of material. This allows fabrication of AZO which remains of good sheet resistance throughout the fabrication process. Shunt resistance losses inspired a study of highly resistive and transparent (HRT) zinc oxide made by reactive sputtering with oxygen, which can be used as a buffer for shunts. Data on resisitivity as a function of oxygen in the sputter gas is given when using doped and undoped zinc oxygen sputter targets. Calculations on theoretical effects of such buffer layers are also presented. A high temperature cadmium chloride (CdCl2) treatment is needed to create high efficiency CdTe cells. This can be a difficult step for flexible cells, as it can lead to CdTe film delamination. We have optimized a treatment for flexible cells and found that conditions, different from those which are optimal for cells on glass, allows high performance with no delamination. Understanding of these issues allowed progress in the performance of our cells fabricated on flexible substrates. Ultimately, we have fabricated a flexible CdTe cell with efficiency of 10.5%. This efficiency is, to our knowledge, the best of any flexible CdTe cell which uses zinc oxide as a transparent conducting oxide. The performance of these cells also compares favorably to the best overall flexible CdTe cells.
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 Thin Film Solar Cells written by I. M. Dharmadasa and published by CRC Press. This book was released on 2018-09-05 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar energy conversion plays a very important role in the rapid introduction of renewable energy, which is essential to meet future energy demands without further polluting the environment, but current solar panels based on silicon are expensive due to the cost of raw materials and high energy consumption during production. The way forward is to move towards thin-film solar cells using alternative materials and low-cost manufacturing methods. The photovoltaic community is actively researching thin-film solar cells based on amorphous silicon, cadmium telluride (CdTe), copper indium gallium diselenide (CIGS), and dye-sensitised and organic materials. However, progress has been slow due to a lack of proper understanding of the physics behind these devices. This book concentrates on the latest developments and attempts to improve our understanding of solid-state device physics. The material presented is mainly experimental and based on CdTe thin-film solar cells. The author extends these new findings to CIGS thin-film solar cells and presents a new device design based on graded bandgap multi-layer solar cells. This design has been experimentally tested using the well-researched GaAs/AlGaAs system, and initial devices have shown impressive device parameters. These devices are capable of absorbing all radiation (UV, visible and infra-red) within the solar spectrum and combine "impact ionisation" and "impurity photovoltaic" effects. The improved device understanding presented in this book should impact and guide future photovoltaic device development and low-cost thin-film solar panel manufacture. This new edition features an additional chapter besides exercises and their solutions, which will be useful for academics teaching in this field.
Download or read book II IV Compound Semiconductor Photovoltaic Materials Volume 668 written by Robert Birkmire and published by . This book was released on 2001-10-15 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on materials issues related to Cu(In,Ga)(Se,S)2 and CdTe-based polycrystalline thin-film photovoltaic solar cells and related oxides and chalcogenides. Phase equilibrium and thermochemical kinetic aspects of the absorber layer formation of CdTe and Cu(In,Ga)(Se,S)2 are emphasized and several papers on micro-analytical analysis report on detailed structural properties of thin films. The use of flexible plastic or metal foil substrates as an alternative to glass is addressed in terms of solar-cell performance and limitations imposed by the nature of the substrates. Properties of defects and interfaces in CdTe and CIGSS are highlighted using electrical, optical, and micro-analytical tools. While film properties are correlated to device physics, controversy still exists on the detailed operation of both CdTe and CIGSS devices. Topics include: materials and synthesis; thin films on alternate substrates; defects; growth and junction formation; surfaces and interfaces and film and device characterization.
