Download or read book Heavily Doped Carrier selective Regions for Silicon Solar Cells written by Di Yan and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: While heavily doped regions are an integral part of conventional silicon solar cells for carrier separation and selective transport, they also introduce deleterious effects that constrain their performance. This thesis addresses the fundamental limitations imposed by heavy doping in silicon solar cells and explores the potential of utilising doping in a manner that circumvents them. In particular, selectively doped regions and novel carrier-selective passivating contacts are developed. In heavily doped silicon, energy band gap narrowing (BGN) occurs. Subsequently, the pn product in equilibrium increases, which tends to limit the performance of silicon solar cells. In principle, heavily doped silicon should be analyzed using Fermi-Dirac statistics coupled with a BGN model. Nevertheless, applying Schenk's theoretical BGN model to experimental samples underestimates their corresponding recombination current parameters. Based on a large number of samples and using well-proven models for Auger recombination and carrier mobility, updated empirical expressions for the BGN are derived here for both n-type and p-type silicon. The study confirms that the BGN values in p-type silicon are slightly larger than in n-type silicon. Both updated BGN models contribute to a more complete understanding of the losses and ramifications caused by heavily doped regions in silicon solar cells. A possible approach to reduce the impact of heavily doped regions is to reduce the area they occupy, restricting it to underneath the metal contacts. In this thesis a process to implement such selectively doped (SD) silicon solar cells is developed. The process, based on a controlled etch-back of the diffused region offers the advantage of being self-aligned, which avoids the critical mask alignment step. The TMAH based etch-back solution used here provides a well-controlled etching rate, uniformly etched surface and selectivity to metallic layers (Al or Ag). The poof-of-concept SD silicon solar cells have reached a conversion efficiency of 17.5%. Inspired by silicon heterojunction solar cells and polysilicon emitter BJT, carrier-selective passivating contacts based on heavily doped silicon films are developed. Two approaches of depositing intrinsic polysilicon or amorphous silicon are demonstrated. In both cases, a thermal diffusion process is used to dope and recrystallise the films. The diffusion processes, the intrinsic silicon film thickness, and the interfacial layer conditions are optimized in terms of the trade-off between the recombination current parameter and the contact resistivity. The interfacial layer is found to be critical for blocking the penetration of dopants, for stopping the epitaxial regrowth between the top silicon film and the underlying crystalline silicon, as well as for enhancing the response to a subsequent hydrogenation treatment. Examination of these carrier-selective passivating contact structures before and after the thermal diffusion processes by using XRD, micro-PL and XPS indicates that allowing a moderate level of phosphorus into the silicon oxide and into the silicon substrate is necessary to achieve a low recombination and a low contact resistivity. The electron-selective passivating contacts have been successfully implemented at the rear of n-type silicon solar cells, showing open circuit voltage of > 672 mV and efficiency values up to 20.8%.
Download or read book Characterisation and modeling of highly doped regions in silicon solar cells written by Freerk J. Bisschop and published by . This book was released on 1992 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Silicon Heterojunction Solar Cells written by W.R. Fahrner and published by Trans Tech Publications Ltd. This book was released on 2006-08-15 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world of today must face up to two contradictory energy problems: on the one hand, there is the sharply growing consumer demand in countries such as China and India. On the other hand, natural resources are dwindling. Moreover, many of those countries which still possess substantial gas and oil supplies are politically unstable. As a result, renewable natural energy sources have received great attention. Among these, solar-cell technology is one of the most promising candidates. However, there still remains the problem of the manufacturing costs of such cells. Many attempts have been made to reduce the production costs of conventional solar cells (manufactured from monocrystalline silicon using diffusion methods) by instead using cheaper grades of silicon, and simpler pn-junction fabrication. That is the hero of this book; the heterojunction solar cell.
Download or read book Advanced Contacts For Crystalline Silicon Solar Cells written by James Bullock and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mainstream dopant-diffused crystalline silicon (c-Si) solar cells have reached a point in their development where losses at the directly-metalized, heavily-doped regions have a significant, and often limiting effect on device performance. The conventional wisdom on addressing this issue is to drastically reduce the percentage of the contacted surface area-to less than 1% in some cases-significantly increasing the complexity of fabrication. An alternative approach is to focus on addressing the losses at the metal / cSi interface by implementing novel 'carrier-selective' contacting structures. This approach to solar cell contacting has the potential to increase the output power whilst significantly simplifying cell architectures and fabrication procedures. This thesis is centered on the conceptual and experimental development of a number of advanced contacting structures for c-Si solar cells, collectively referred to here as 'heterocontacts'. The 'carrier-selectivity' of the contact, that is, how well it collects just one of the two carriers (whilst preserving the other), is used as a universal concept for comparing different contacting strategies, including mainstream contacts based on direct metallization of heavily doped c-Si. To provide a foundation on this topic the initial section of the thesis discusses the concept and theory of carrier-selectivity. This is complemented with an in depth literature review of current state-of-the-art contacting practices for c-Si solar cells. This provides a reference frame with which to compare the three experimental chapters that follow. In the first experimental chapter it is shown that a suitable initial stepping stone towards advancing solar c-Si cell contacts is to combine the benefits of conventional dopant-diffused regions with those of heterocontacts. A number of such hybrid systems are demonstrated and optimized at the contact level through multiple dedicated studies focused on using thin silicon oxide (SiOx), aluminum oxide (AlOx) or hydrogenated amorphous silicon (a-Si:H) passivating interlayers. These interlayers are shown to reduce carrier recombination at the contact surface by up to two orders of magnitude. In a later study we develop and demonstrate a novel a-Si:H enhanced Al / SiOx / c-Si(n+) heterocontact concept. This structure is also explored at the solar cell level, yielding an efficiency of 21% in the initial stages of development - equivalent to that of an analogous cell made with the conventional directly metallized partial contact technique. In the succeeding chapter, the logical next stage in the development of such a concept is explored, that is, to completely remove the heavily doped surface regions, instead using the heterocontacts exclusively to separate electrons and holes. It is demonstrated that this can be achieved using materials with extreme work functions. For the collection of holes, sub-stoichiometric molybdenum oxide MoOx is utilized, favored for its transparency and large work function. Over multiple studies, it is demonstrated that MoOx heterocontact systems, both with and without passivating interlayers can be used to effectively collect holes on both n and p-type c-Si absorbers. This enables its application to a number of novel solar cells architectures, most prominently a novel MoOx partial rear contact cell attaining conversion efficiencies over 20% in the initial proof-ofconcept stage. In the final experimental chapter, a complementary electron heterocontact system is developed, based on a low work function LiFx / Al electrode. This is shown to provide ix excellent electron collection characteristics, both with and without a-Si:H passivating interlayers. The exceptional contact characteristics enabled by this heterocontact allow the demonstration of a first-of-its-kind n-type partial rear contact cell already with an efficiency above 20% in its first demonstration. To conclude the thesis and demonstrate its premise, a novel c-Si cell is developed without the use of dopants. This cell, referred to as the dopant free asymmetric heterocontact (DASH) cell, combines the previously mentioned MoOx based hole contacts and LiFx based electron heterocontacts, both with passivating a-Si:H interlayers. A conversion efficiency of 19.4% is attained for this proof-of-concept device - an improvement by more than 5 percent absolute from the previous DASH cell record and more importantly the first demonstration of such a concept to be competitive with conventional cell designs.
Download or read book New Research on Silicon written by Vitalyi Igorevich Talanin and published by BoD – Books on Demand. This book was released on 2017-05-31 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: The knowledge of fundamental silicon questions and all aspects of silicon technology gives the possibility of improvement to both initial silicon material and devices on silicon basis. The articles for this book have been contributed by the much respected researchers in this area and cover the most recent developments and applications of silicon technology and some fundamental questions. This book provides the latest research developments in important aspects of silicon including nanoclusters, solar silicon, porous silicon, some technological processes, and silicon devices and also fundamental question about silicon structural perfection. This book is of interest both to fundamental research and to practicing scientists and also will be useful to all engineers and students in industry and academia.
Download or read book Handbook of Research on Solar Energy Systems and Technologies written by Anwar, Sohail and published by IGI Global. This book was released on 2012-08-31 with total page 615 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last ten years have seen rapid advances in nanoscience and nanotechnology, allowing unprecedented manipulation of the nanoscale structures controlling solar capture, conversion, and storage. Filled with cutting-edge solar energy research and reference materials, the Handbook of Research on Solar Energy Systems and Technologies serves as a one-stop resource for the latest information regarding different topical areas within solar energy. This handbook will emphasize the application of nanotechnology innovations to solar energy technologies, explore current and future developments in third generation solar cells, and provide a detailed economic analysis of solar energy applications.
Download or read book Ionized Dopant Concentrations at the Heavily Doped Surface of a Silicon Solar Cell written by Lewis Research Center and published by . This book was released on 1978 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterisation and modeling of highly doped regions in silicon solar cells written by Freerk J. Bisschop and published by . This book was released on 1992 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar Cells and Light Management written by Francesco Enrichi and published by Elsevier. This book was released on 2019-10-29 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar Cells and Light Management: Materials, Strategies and Sustainability provides an extensive review on the latest advances in PV materials, along with light management strategies for better exploiting the solar spectrum. Following a brief review of the current status of solar cells, the book discusses different concepts, principles and technologies for solar devices, starting with standard silicon cells and then covering organic-hybrid, DSSC, perovskite, quantum dots and nanostructured oxide solar cells. Other sections focus on light manipulation and spectral modification, materials for spectral conversion, and environmental and sustainably considerations. An emergy analysis, which is an extension of the Life Cycle Assessment methodology, is applied to the study of solar PV systems, thus allowing for effective integrated indicators. Provides a comprehensive picture of light management strategies Features the most recent advances in the field, including novel materials and advanced solar cell technologies Presents a resource that is applicable to both new or experienced researchers in the field Contains a section on environmental and sustainability issues
Download or read book Materials Concepts For Solar Cells Second Edition written by Thomas Dittrich and published by World Scientific Publishing Company. This book was released on 2018-01-30 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: A modern challenge is for solar cell materials to enable the highest solar energy conversion efficiencies, at costs as low as possible, and at an energy balance as sustainable as necessary in the future. This textbook explains the principles, concepts and materials used in solar cells. It combines basic knowledge about solar cells and the demanded criteria for the materials with a comprehensive introduction into each of the four classes of materials for solar cells, i.e. solar cells based on crystalline silicon, epitaxial layer systems of III-V semiconductors, thin-film absorbers on foreign substrates, and nano-composite absorbers. In this sense, it bridges a gap between basic literature on the physics of solar cells and books specialized on certain types of solar cells.The last five years had several breakthroughs in photovoltaics and in the research on solar cells and solar cell materials. We consider them in this second edition. For example, the high potential of crystalline silicon with charge-selective hetero-junctions and alkaline treatments of thin-film absorbers, based on chalcopyrite, enabled new records. Research activities were boosted by the class of hybrid organic-inorganic metal halide perovskites, a promising newcomer in the field.This is essential reading for students interested in solar cells and materials for solar cells. It encourages students to solve tasks at the end of each chapter. It has been well applied for postgraduate students with background in materials science, engineering, chemistry or physics.
Download or read book Nanostructured Solar Cells written by Narottam Das and published by BoD – Books on Demand. This book was released on 2017-02-22 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanostructured solar cells are very important in renewable energy sector as well as in environmental aspects, because it is environment friendly. The nano-grating structures (such as triangular or conical shaped) have a gradual change in refractive index which acts as a multilayer antireflective coating that is leading to reduced light reflection losses over broadband ranges of wavelength and angle of incidence. There are different types of losses in solar cells that always reduce the conversion efficiency, but the light reflection loss is the most important factor that decreases the conversion efficiency of solar cells significantly. The antireflective coating is an optical coating which is applied to the surface of lenses or any optical devices to reduce the light reflection losses. This coating assists for the light trapping capturing capacity or improves the efficiency of optical devices, such as lenses or solar cells. Hence, the multilayer antireflective coatings can reduce the light reflection losses and increases the conversion efficiency of nanostructured solar cells.
Download or read book Printed Electronics written by Ilgu Yun and published by . This book was released on 2016-09-28 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Front Side Technology on Crystalline Silicon Solar Cells written by and published by Victor Prajapati. This book was released on with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Efficiency Crystalline Silicon Solar Cells written by Eun-Chel Cho and published by MDPI. This book was released on 2021-01-06 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is composed of 6 papers. The first paper reports a novel technique for the selective emitter formation by controlling the surface morphology of Si wafers. Selective emitter (SE) technology has attracted renewed attention in the Si solar cell industry to achieve an improved conversion efficiency of passivated-emitter rear-contact (PERC) cells. In the second paper, the temperature dependence of the parameters was compared through the PERC of the industrial-scale solar cells. As a result of their analysis, PERC cells showed different temperature dependence for the fill factor loss as temperatures rose. The third paper reports the effects of carrier selective front contact layer and defect state of hydrogenated amorphous silicon passivation layer/n-type crystalline silicon interface. The results demonstrated the effects of band offset determined by band bending at the interface of the passivation layer and carrier selective front contact layer. In addition, the nc-SiOx: H CSFC layer not only reduces parasitic absorption loss but also has a tunneling effect and field-effect passivation. The fourth paper reports excimer laser annealing of hydrogenated amorphous silicon film for TOPCon solar cell application. This paper analyzes the crystallization of a-Si:H via excimer laser annealing (ELA) and compared this process with conventional thermal annealing. The fifth paper reports the contact mechanism between Ag–Al and Si and the change in contact resistance (Rc) by varying the firing profile. Rc was measured by varying the belt speed and peak temperature of the fast-firing furnace. The sixth paper reports a silicon tandem heterojunction solar cell based on a ZnO/Cu2O subcell and a c-Si bottom subcell using electro-optical numerical modeling. The buffer layer affinity and mobility together with a low conduction band offset for the heterojunction are discussed, as well as spectral properties of the device model.
Download or read book Energy Efficiency Improvements in Smart Grid Components written by Moustafa Eissa and published by BoD – Books on Demand. This book was released on 2015-04-22 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is intended for academics and engineers who are working in universities, research institutes, utility and industry sectors wishing to enhance their idea and get new information about the energy efficiency developments in smart grid. The readers will gain special experience with deep information and new idea about the energy efficiency topics. This book includes lots of problems and solutions that can easily be understood and integrated into larger projects and researches. The book enables some studies about monitoring, management and measures related to smart grid components, Energy Efficiency Improvements in smart grid components and new intelligent Control strategies for Distributed energy resources, boosting PV systems, electrical vehicles, etc. It included optimization concepts for power system, promoting value propositions; protection in power system, etc. The book also has some recent developments in solar cell technologies, LEDs and non thermal plasma technology. As I enjoyed preparing this book I am sure that it will be very valuable for large sector of readers.
Download or read book Solar Energy Update written by and published by . This book was released on 1984-12 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atomic Layer Deposition in Energy Conversion Applications written by Julien Bachmann and published by John Wiley & Sons. This book was released on 2017-03-15 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combining the two topics for the first time, this book begins with an introduction to the recent challenges in energy conversion devices from a materials preparation perspective and how they can be overcome by using atomic layer deposition (ALD). By bridging these subjects it helps ALD specialists to understand the requirements within the energy conversion field, and researchers in energy conversion to become acquainted with the opportunities offered by ALD. With its main focus on applications of ALD for photovoltaics, electrochemical energy storage, and photo- and electrochemical devices, this is important reading for materials scientists, surface chemists, electrochemists, electrotechnicians, physicists, and those working in the semiconductor industry.
