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Advances In The Characterization Performance And Defect Engineering Of Earth Abundant And Thin Film Materials For Solar Energy Conversion
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Book Synopsis Advances in the Characterization, Performance and Defect Engineering of Earth Abundant and Thin-Film Materials for Solar Energy Conversion by : T. Gershon
Download or read book Advances in the Characterization, Performance and Defect Engineering of Earth Abundant and Thin-Film Materials for Solar Energy Conversion written by T. Gershon and published by . This book was released on 2014 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Structural Defect Engineering of Tin (II) Sulfide Thin Films for Photovoltaics by : Rupak Chakraborty
Download or read book Structural Defect Engineering of Tin (II) Sulfide Thin Films for Photovoltaics written by Rupak Chakraborty and published by . This book was released on 2016 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tin (II) sulfide (SnS) is a promising Earth-abundant, non-toxic alternative to commercially available thin-film photovoltaic (PV) materials because of its near-ideal bandgap, high absorption coefficient, and potential for facile manufacturing. However, SnS-based photovoltaic devices have reached a maximum experimental efficiency of only 4.4%, compared to a theoretical maximum of 32%, primarily due to a low minority-carrier lifetime. In this work, I assess the impact of structural defects and anisotropy on the minority-carrier lifetime and other key device parameters, shedding light on the path to high-efficiency SnS-based photovoltaics. SnS thin films are deposited by thermal evaporation in a range of growth temperatures with varying structural defect density. Extended structural defects including intragranular defects and grain boundaries are directly related to minority-carrier collection length using high-resolution correlative electron microscopy. The results suggest that intragranular point defects, as opposed to extended structural defects, are likely responsible for the short minority-carrier lifetimes in present-day SnS films. Inhomogeneities in the polycrystalline SnS thin films due to the anisotropic material properties of SnS may also impact the device performance. Device simulations taking into account the orientation-dependent electron affinity of SnS show that a uniform grain orientation distribution is optimal. As a route toward both uniform grain orientation and low structural defect density, the anisotropic surface energy of SnS is harnessed by growth on a van der Waals-terminated substrate. An enhancement in both orientation uniformity and minority-carrier lifetime is measured, showing a promising path toward the ideal SnS film. Lastly, the process of optimization to reduce structural defect density may be expedited by in-situ characterization of micro- and nanoscale defects under realistic processing conditions. Toward this end, an in-situ temperature stage for synchrotron X-ray spectromicrosopy is developed to track nanoscale defects up to a sample temperature of 600°C. The stage enables previously unattainable in-situ studies of defect kinetics, allowing both a deeper understanding of how process conditions affect defect characteristics and the ability to rapidly optimize process conditions toward a defect-free film.
Book Synopsis Semiconductor Materials for Solar Photovoltaic Cells by : M. Parans Paranthaman
Download or read book Semiconductor Materials for Solar Photovoltaic Cells written by M. Parans Paranthaman and published by Springer. This book was released on 2015-09-16 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews the current status of semiconductor materials for conversion of sunlight to electricity, and highlights advances in both basic science and manufacturing. Photovoltaic (PV) solar electric technology will be a significant contributor to world energy supplies when reliable, efficient PV power products are manufactured in large volumes at low cost. Expert chapters cover the full range of semiconductor materials for solar-to-electricity conversion, from crystalline silicon and amorphous silicon to cadmium telluride, copper indium gallium sulfide selenides, dye sensitized solar cells, organic solar cells, and environmentally friendly copper zinc tin sulfide selenides. The latest methods for synthesis and characterization of solar cell materials are described, together with techniques for measuring solar cell efficiency. Semiconductor Materials for Solar Photovoltaic Cells presents the current state of the art as well as key details about future strategies to increase the efficiency and reduce costs, with particular focus on how to reduce the gap between laboratory scale efficiency and commercial module efficiency. This book will aid materials scientists and engineers in identifying research priorities to fulfill energy needs, and will also enable researchers to understand novel semiconductor materials that are emerging in the solar market. This integrated approach also gives science and engineering students a sense of the excitement and relevance of materials science in the development of novel semiconductor materials. · Provides a comprehensive introduction to solar PV cell materials · Reviews current and future status of solar cells with respect to cost and efficiency · Covers the full range of solar cell materials, from silicon and thin films to dye sensitized and organic solar cells · Offers an in-depth account of the semiconductor material strategies and directions for further research · Features detailed tables on the world leaders in efficiency demonstrations · Edited by scientists with experience in both research and industry
Book Synopsis Solar Technologies for the 21st Century by : Anco S. Blazev
Download or read book Solar Technologies for the 21st Century written by Anco S. Blazev and published by CRC Press. This book was released on 2021-01-07 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines solar technologies, describes their properties, and evaluates the technological potential of each. It also reviews the logistics of deploying solar energy as a viable and sustainable way to solve urgent energy, environmental, and socio-economic problems. Topics discussed include solar power generation, today’s solar technologies, solar thermal, silicon PV, thin PV, 3-D solar cells, nano-PV, organic solar cells, solar successes and failures, solar power fields, finance and regulations, solar markets and solar energy and the environment.
Book Synopsis Electronic Characterisation of Earth‐Abundant Sulphides for Solar Photovoltaics by : Thomas James Whittles
Download or read book Electronic Characterisation of Earth‐Abundant Sulphides for Solar Photovoltaics written by Thomas James Whittles and published by Springer. This book was released on 2018-07-31 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines the electronic structure of earth-abundant and environmentally friendly materials for use as absorber layers within photovoltaic cells. The corroboration between high-quality photoemission measurements and density of states calculations yields valuable insights into why these materials have demonstrated poor device efficiencies in the vast literature cited. The book shows how the materials’ underlying electronic structures affect their properties, and how the band positions make them unsuitable for use with established solar cell technologies. After explaining these poor efficiencies, the book offers alternative window layer materials to improve the use of these absorbers. The power of photoemission and interpretation of the data in terms of factors generally overlooked in the literature, such as the materials’ oxidation and phase impurity, is demonstrated. Representing a unique reference guide, the book will be of considerable interest and value to members of the photoemission community engaged in solar cell research, and to a wider materials science audience as well.
Book Synopsis Sulfide and Selenide Based Materials for Emerging Applications by : Goutam Kumar Dalapati
Download or read book Sulfide and Selenide Based Materials for Emerging Applications written by Goutam Kumar Dalapati and published by Elsevier. This book was released on 2022-06-17 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sulfide and Selenide-Based Materials for Emerging Applications explores a materials and device-based approach to the transition to low-cost sustainable thin film photovoltaic devices and energy storage systems. Part 1 examines recent advances in renewable technologies and materials for sustainable development, as well as photovoltaic energy storage devices. Part 2 discusses thin film solar cells with earth abundant materials, highlighting the power conversion efficiency of the kesterite-based solar cells. Kesterite film technology including different synthesis and doping method designs are also discussed, along with emerging sulfide semiconductors with potential in thin film photovoltaics/flexible devices. In Part 3 sulfur- and selenides-based materials for thermoelectric applications are explored. Part 4 covers chalcogenide semiconductors with applications in electrochemical water splitting for green hydrogen generation and oxygen generation, as well as the latest research on layered 2D transition metal chalcogenides for electrochemical water splitting. To conclude, part 5 discusses recent developments of storage technologies such as Li-S batteries, sulfide-based supercapacitors and metal-ion batteries, and the development of 3D printing sulfides/selenides for energy conversion and storage. This book is a useful resource for those involved in green energy technology and decarbonization and is designed for a broad audience, from students to experienced scientists. Discusses the emerging sulfide/selenide based thin film absorber materials and their deposition methods Previews device engineering techniques that have been developed to enhance the power conversion efficiency and lifetime of sulfide/selenide based thin film solar cells Provides an update on what low cost sulfide/selenide based electro-catalysts have become available and the comparison of their performance vs. noble metal catalysts
Book Synopsis Development of Earth-abundant Materials and Low-cost Processes for Solar Cells by : Chih-Liang Wang
Download or read book Development of Earth-abundant Materials and Low-cost Processes for Solar Cells written by Chih-Liang Wang and published by . This book was released on 2014 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of renewable solar energy research is to develop low-cost, high-efficiency photovoltaic technologies. However, with the growing deployment of solar cells, approaching the terawatt scale, absorber materials reliant upon rare or unfriendly elements become a crucial issue. Thus, the primary objective of this dissertation is the development of a low-cost fabrication method for (i) thin-film solar cells and (ii) dye-sensitized solar cells using earth-abundant materials. In thin-film solar cells, the kesterite Cu2ZnSnS4 with earth abundant elements is used as an absorber layer. It possesses a high absorption coefficient, direct band gap, and good long-term stability compared to the traditional CdTe and Cu(In,Ga)(S,Se)2 (CIGS) absorber layers. A facile hot-injection approach for synthesizing Cu2ZnSn(S,Se)4 nanocrystals with varied Se to (S+Se) ratio is developed to systematically investigate the role of Se in Cu2ZnSn(S,Se)4 nanocrystals and the evolution of Cu2ZnSn(S,Se)4 nanocrystals to Cu2ZnSn(S,Se)4 film during the sulfurization step to address the problems associated with its narrow compositional window and the loss of Sn during heat treatment. Additionally, the existing substrate-type device configuration for these solar cells uses a molybdenum (Mo) back contact, which suffers from serious disadvantages like the (i) presence of a Schottky barrier at the Mo/Cu2ZnSn(S,Se)4 interface and (ii) decomposition of Cu2ZnSn(S,Se)4 at the Mo interface. Accordingly, a low-cost and Mo-free superstrate-type device configuration of Au/Cu2ZnSn(S,Se)4/CdS/TiO2/ITO/glass is developed to evaluate the conversion efficiency and to avoid the occurrence of a Schottky barrier at the interface and potential decomposition pathways induced by the formation of Mo(S,Se)2. Furthermore, with the addition of ethyl cellulose, the loss of Sn associated with the conversion of CZTSe to CZTSSe during the grain growth process is mitigated, leading to an increase in the conversion efficiency compared to that of the precursor film without using ethyl cellulose. Such an improvement can provide insight into the grain growth of CZTSSe during the sulfurization process and thereby enhance the feasibility of sustainable, high efficiency CZTSSe solar devices. The excellent characteristics of dye-sensitized solar cells (DSSCs) with short energy-payback time, simple assembly, and eco-friendly features make them a potential option to utilize solar energy. Accordingly, a facile, low-cost, template-free route for TiO2 hollow submicrospheres embedded with SnO2 nanobeans is developed for use as a versatile scattering layer in DSSCs. Our designed structure simultaneously promotes dye adsorption, light harvesting, and electron transport, leading to a 28 % improvement in the conversion efficiency as compared with the film-based SnO2. In addition, a naturally-derived carbonaceous material as a Pt-free counter electrode for DSSCs is also developed for the first time: carbonized sucrose-coated eggshell membrane (CSEM). It is found that the carbonized sucrose-coated eggshell membranes consist of unique micropores of less than 2 nm, which effectively catalyze the triiodide into iodide in the light-electricity conversion process, leading to an improvement in the V [subscript oc] and a competitive efficiency as compared to that of a DSSC with a traditional Pt-based counter electrode.
Book Synopsis Thin Film Solar Cells by : Jef Poortmans
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.
Book Synopsis Chemical Solution Deposition of Functional Oxide Thin Films by : Theodor Schneller
Download or read book Chemical Solution Deposition of Functional Oxide Thin Films written by Theodor Schneller and published by Springer Science & Business Media. This book was released on 2014-01-24 with total page 801 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first text to cover all aspects of solution processed functional oxide thin-films. Chemical Solution Deposition (CSD) comprises all solution based thin- film deposition techniques, which involve chemical reactions of precursors during the formation of the oxide films, i. e. sol-gel type routes, metallo-organic decomposition routes, hybrid routes, etc. While the development of sol-gel type processes for optical coatings on glass by silicon dioxide and titanium dioxide dates from the mid-20th century, the first CSD derived electronic oxide thin films, such as lead zirconate titanate, were prepared in the 1980’s. Since then CSD has emerged as a highly flexible and cost-effective technique for the fabrication of a very wide variety of functional oxide thin films. Application areas include, for example, integrated dielectric capacitors, ferroelectric random access memories, pyroelectric infrared detectors, piezoelectric micro-electromechanical systems, antireflective coatings, optical filters, conducting-, transparent conducting-, and superconducting layers, luminescent coatings, gas sensors, thin film solid-oxide fuel cells, and photoelectrocatalytic solar cells. In the appendix detailed “cooking recipes” for selected material systems are offered.
Book Synopsis Optoelectronic and Defect Properties in Earth Abundant Photovoltaic Materials: First-principle Calculations by : Tingting Shi
Download or read book Optoelectronic and Defect Properties in Earth Abundant Photovoltaic Materials: First-principle Calculations written by Tingting Shi and published by . This book was released on 2014 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, a series of earth-abundant photovoltaic materials including lead halide perovskites, copper based compounds, and silicon are investigated via density functional theory (DFT). Firstly, we study the unique optoelectronic properties of perovskite CH3NH3PbI3 and CH3NH3PbBr3. First-principle calculations show that CH3NH3PbI3 perovskite solar cells exhibit remarkable optoelectronic properties that account for the high open circuit voltage (Voc) and long electron-hole diffusion lengths. Our results reveal that for intrinsic doping, dominant point defects produce only shallow levels. Therefore lead halide perovskites are expected to exhibit intrinsic low non-radiative recombination rates. The conductivity of perovskites can be tuned from p-type to n-type by controlling the growth conditions. For extrinsic defects, the p-type perovskites can be achieved by doping group-IA, -IB, or -VIA elements, such as Na, K, Rb, Cu, and O at I-rich growth conditions. We further show that despite a large band gap of 2.2 eV, the dominant defects in CH3NH3PbBr3 also create only shallow levels. The photovoltaic properties of CH3NH3PbBr3-based perovskite absorbers can be tuned via defect engineering. Highly conductive p-type CH3NH3PbBr3 can be synthesized under Br-rich growth conditions. Such CH3NH3PbBr3 may be potential low-cost hole transporting materials for lead halide perovskite solar cells. All these unique defect properties of perovskites are largely due to the strong Pb lone-pair s orbital and I p (Br p) orbital antibonding coupling and the high ionicity of CH3NH3PbX3 (X=I, Br). Secondly, we study the optoelectronic properties of Cu-V-VI earth abundant compounds. These low cost thin films may have the good electronic and optical properties. We have studied the structural, electronic and optical properties of Cu3-V-VI4 compounds. After testing four different crystal structures, enargite, wurtzite-PMCA, famatinite and zinc-blend-PMCA, we find that Cu3PS4 and Cu3PSe4 prefer energetically the enargite structure, whereas, other compounds favor the famatinite structure. Among the compounds and structures considered, enargite Cu3PSe4, and famatinite Cu3AsS4, are suitable for single junction solar cell applications due to bandgaps of 1.32 eV and 1.15 eV, respectively. Furthermore, CuSbS2 are also studied by density functional theory and HSE06 hybrid functional. The chalcostibite CuSbS2 has an indirect band gap of 1.85 eV, whereas the chalcogenide Cu3SbS4 has a direct band gap of 0.89 eV. We find that the large difference on band gaps is mainly attributed to the different Sb charge states. We further predict that the Sb charge states will affect the defect physics. Particularly, the Sb lone pair s orbitals in CuSbS2 have strong influence on the formation energies of Sb-related defects. Lastly, we have studied the atomic structure and electronic properties of aluminum (Al)-related defect complexes in silicon. We find a unique stable complex configuration consisting of an Ali and an oxygen dimer, Ali-2Oi, which introduces deep levels in the band gap of Si. The formation energies of the Ali-2Oi complexes could be lower than that of individual Ali atoms under oxygen-rich conditions. The formation of Ali-2Oi complexes may explain the experimental observation that the coexistence of Al and O results in reduced carrier lifetime in Si wafers.
Book Synopsis Thin Film Solar Cells with Earth Abundant Elements by : Yue Yu
Download or read book Thin Film Solar Cells with Earth Abundant Elements written by Yue Yu and published by . This book was released on 2017 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world energy consumption has increased rigorously in recent years due to the rapid economic development and the massive global population expansion. Today the world energy supply relies heavily on fossil fuels, known as non-renewable energy resources, which have limited reserves on Earth and do not form or replenish in a short period of time. Burning fossil fuels not only brings environmental pollutions but also results in carbon dioxide and other greenhouse gases, which are to blame for global warming. Therefore, to build a more sustainable and greener future, we have to develop alternative renewable energy resources. Photovoltaic (PV) cell, also commonly known as solar cell, is a very promising renewable energy technology. Here in this dissertation, we have studied two emerging PV materials with earth abundant elements, i.e. copper zinc tin sulfide (CZTS) and organic-inorganic hybrid halide perovskite. Having earth abundant elements means that the raw materials have rich reserves on Earth and the costs are relatively low. It also means that the materials have the potential capability to be produced in large scales in industry. We first explored two different deposition methods for preparing CZTS thin films. In the first method, the CZTS was fabricated by a solution based method with diethyl sulfoxide (DMSO) as the solvent and the effect of spin speed on the properties of CZTS thin films was studied. The results indicated that a higher spin speed was more favorable for attaining a more densely packed and pinhole-free film while no crystallographic differences were observed. In the second method, CZTS was fabricated using sputtered metal precursors followed by a closed-space sulfurization (CSS) technique, which had high manufacturing compatibility and could be applied in industry. After exploring different sulfurization conditions, including temperatures and time, the champion cell was obtained at 590oC for 30min, with a maximum power conversion efficiency (PCE) of 5.2%. We then explored three different organic-inorganic hybrid halide perovskite materials for solar cell applications. The first perovskite material is methylammonium tin triiodide (MASnI3, bandgap ~1.3 eV). It was fabricated by a hybrid thermal evaporation. The as-deposited MASnI3 thin films exhibit smooth surfaces, uniform coverage across the entire substrate, and strong crystallographic preferred orientation along the 100 direction. Our results demonstrate the potential capability of the hybrid evaporation method for preparing high-quality MASnI3 perovskite thin films which can be used to fabricate efficient lead (Pb)-free perovskite solar cells (PVSCs). The second perovskite material is mixed-cation (formamidinium and cesium) lead iodide (FA0.8Cs0.2PbI3). We find that one of the main factors limiting the PCEs of FA0.8Cs0.2PbI3 PVSCs could be the small grain sizes, which leads to relatively short mean carrier lifetimes. We further find that adding a small amount of lead thiocyanate additive can enlarge the grain size of FA0.8Cs0.2PbI3 perovskite thin films and significantly increase the mean carrier lifetime. As a result, the average PCE of FA0.8Cs0.2PbI3 PVSCs increases from 16.18 ± 0.50 (13.45 ± 0.78)% to 18.16 ± 0.54 (16.86 ± 0.63)% when measured under reverse (forward) voltage scans. The best-performing FA0.8Cs0.2PbI3 PVSC registers a PCE of 19.57 (18.12) % when measured under a reverse (forward) voltage scan. The third perovskite material is FA0.8Cs0.2Pb(I0.7Br0.3)3 (bandgap ~1.75 eV). We find that the cooperation of lead thiocyanate additive and a solvent annealing process can effectively increase the grain size of the perovskite thin films while avoiding the undesired excess lead iodide formation. As a result, the average grain size of the FA0.8Cs0.2Pb(I0.7Br0.3)3 perovskite thin films increases from 66 ± 24 nm to 1036 ± 111 nm and the mean carrier lifetime shows a more than 3-fold increase, from 330 ns to over 1000 ns. As a result, the average open-circuit voltage (Voc) of FA0.8Cs0.2Pb(I0.7Br0.3)3 PVSCs increases by 80 (70) mV and the average PCE increases from 13.44 ± 0.48 (11.75 ± 0.34)% to 17.68 ± 0.36 (15.58 ± 0.55)% when measured under reverse (forward) voltage scans. The best-performing wide-bandgap (~1.75 eV) PVSC registers a stabilized PCE of 17.18%, demonstrating its suitability for top cell applications in all-perovskite tandem solar cells.
Book Synopsis Developing Cuprous Oxide Thin Film Characterization Techniques to Illuminate Efficiency-limiting Mechanisms in Photovoltaic Applications by : Riley Eric Brandt
Download or read book Developing Cuprous Oxide Thin Film Characterization Techniques to Illuminate Efficiency-limiting Mechanisms in Photovoltaic Applications written by Riley Eric Brandt and published by . This book was released on 2011 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Future fossil fuel scarcity and environmental degradation have demonstrated the need for renewable, low-carbon sources of energy to power an increasingly industrialized world. Solar energy, with its extraordinary resource base, is one of the most feasible long-term options for satisfying energy demand with minimal environmental impact. However, solar photovoltaic panels remain expensive and employ materials whose resource bases cannot satisfy global, terawatt-level penetration. This necessitates the development of cheap, earth-abundant semiconductors for solar conversion such as cuprous oxide (Cu2O). Poor solar energy conversion efficiency (2%) has hindered the development of this material, yet it is not well understood what is preventing the material from approaching the idealized maximum efficiency of 20%. The present work aims to develop a thorough characterization method for Cu2O thin films fabricated through a physical vapor deposition (PVD) process known as reactive direct-current magnetron sputtering. This both provides a platform for material analysis and an opportunity to adapt a typically high-throughput manufacturing method to make high quality thin films. Spectrophotometry, Hall Effect mobility measurement, and photoelectrochemical cell techniques are used in succession to determine the absorption and transport properties. The films are found to have a direct forbidden bandgap of 1.93 eV, with an absorption coefficient of greater than 105 cm-1 for photons carrying energy in excess of 2.6 eV. Majority carrier mobility is measured as 58.1 cm2/V·s, approaching the levels of monocrystalline oxidized films in literature. These high mobilities indicate that with carrier lifetime 10 nanoseconds, minority carrier diffusion length could easily exceed the film thickness. The photoelectrochemical minority carrier diffusion length measurement achieves success on gallium arsenide test samples, determining flat-band potential, quantum efficiency, and minority carrier diffusion length, paving the way for future Cu2O measurement. Future work may apply this test procedure to fully characterize other materials, and eventually lead to solar cell fabrication.
Book Synopsis Characterization of Cu2ZnSnSe4 Kesterite Thin Film Solar Cells by : Lisa Carina Mareike Risch
Download or read book Characterization of Cu2ZnSnSe4 Kesterite Thin Film Solar Cells written by Lisa Carina Mareike Risch and published by . This book was released on 2016 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present thesis deals with the characterization of Cu2ZnSnSe4 (CZTSe) kesterite thin film solar cells. Over the last years, kesterite based devices have attracted growing attention. As Cu, Sn and Zn are earth-abundant metals, the kesterite compounds are promising candidates as absorber materials for the mass production of low-cost photovoltaic devices. However, kesterite solar cells suffer from a severe open circuit voltage (Voc) deficit in comparison with other PV technologies, resulting in a significant performance gap between thin film kesterite and chalcopyrite (CIGS) based devices. Best reported efficiencies for the related CIGS thin film technology are 22.6% at cell size and 17.9% for a commercial module - very close to the performance of Si solar cells - while kesterite solar cells remain below 13% power conversion efficiency. Understanding the fundamental properties of kesterite materials and devices and solving challenges associated with their fabrication are the key to improve device performances.In the framework of this thesis, different loss mechanisms related to the low Voc values of kesterite solar cells have been identified and characterized. Two major factors are thereby observed to be responsible for the significant Voc deficit: non-radiative recombination and band tailing. These aspects are related to the presence of secondary phases and defects that have a significant impact on the pn-heterojunction. Therefore, this thesis focuses on the detection of secondary phases and defects and the role of the n-type buffer layer.
Book Synopsis 5th FORUM ON NEW MATERIALS by : Pietro Vincenzini
Download or read book 5th FORUM ON NEW MATERIALS written by Pietro Vincenzini and published by Trans Tech Publications Ltd. This book was released on 2010-10-27 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 47 peer-reviewed papers collected here together offer a plenitude of up-to-date information on Thermal-to-Electrical Energy Conversion, Photovoltaic Solar Energy Conversion and Concentrating Solar Technologies. The papers are conveniently arranged into MATERIALS FOR DIRECT THERMAL-TO-ELECTRICAL ENERGY CONVERSION, MATERIALS FOR PHOTOVOLTAIC SOLAR ENERGY CONVERSION, Crystalline Cells and Thin Film Photovoltaics, Emerging and New Generation Solar Cells, MATERIALS FOR CONCENTRATING SOLAR TECHNOLOGIES, CPV Materials and Technologies, CSP Materials and Technologies, CPV and CSP Application.
Book Synopsis Study of Earth Abundant TCO and Absorber Materials for Photovoltaic Applications by : Tejas Prabhakar
Download or read book Study of Earth Abundant TCO and Absorber Materials for Photovoltaic Applications written by Tejas Prabhakar and published by . This book was released on 2013 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to make photovoltaic power generation a sustainable venture, it is necessary to use cost-effective materials in the manufacture of solar cells. In this regard, AZO (Aluminum doped Zinc Oxide) and CZTS (Copper Zinc Tin Sulfide) have been studied for their application in thin film solar cells. While AZO is a transparent conducting oxide, CZTS is a photovoltaic absorber. Both AZO and CZTS consist of earth abundant elements and are non-toxic in nature. Highly transparent and conductive AZO thin films were grown using RF sputtering. The influence of deposition parameters such as working pressure, RF power, substrate temperature and flow rate on the film characteristics was investigated. The as-grown films had a high degree of preferred orientation along the (002) direction which enhanced at lower working pressures, higher RF powers and lower substrate temperatures. Williamson-Hall analysis on the films revealed that as the working pressure was increased, the nature of stress and strain gradually changed from being compressive to tensile. The fall in optical transmission of the films was a consequence of free carrier absorption resulting from enhanced carrier density due to incorporation of Al atoms or oxygen vacancies. The optical and electrical properties of the films were described well by the Burstein-Moss effect. CZTS absorber layers were grown using ultrasonic spray pyrolysis at a deposition temperature of 350 C and subsequently annealed in a sulfurization furnace. Measurements from XRD and Raman spectra confirmed the presence of pure single phase Cu2ZnSnS4 . Texture analysis of as-deposited and annealed CZTS films indicated that the (112) plane which is characteristic of the kesterite phase was preferred. The grain size increased from 50 nm to 100 nm on conducting post-deposition annealing. CZTS films with stoichiometric composition yielded a band gap of 1.5 eV, which is optimal for solar energy conversion. The variation of tin in the film changed its resistivity by several orders of magnitude and subsequently the tin free ternary chalcogenide Cu2ZnS2 having very low resistivity was obtained. By carefully optimization of concentrations of tin, zinc and copper, a zinc-rich/tin-rich/copper-poor composition was found to be most suitable for solar cell applications. Etching of CZTS films using KCN solution reduced their resistivity, possibly due to the elimination of binary copper sulfide phases. CZTS solar cells were fabricated both in the substrate and superstrate configurations.
Book Synopsis Printable Solar Cells by : Nurdan Demirci Sankir
Download or read book Printable Solar Cells written by Nurdan Demirci Sankir and published by John Wiley & Sons. This book was released on 2017-04-19 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an overall view of the new and highly promising materials and thin film deposition techniques for printable solar cell applications. The book is organized in four parts. Organic and inorganic hybrid materials and solar cell manufacturing techniques are covered in Part I. Part II is devoted to organic materials and processing technologies like spray coating. This part also demonstrates the key features of the interface engineering for the printable organic solar cells. The main focus of the Part III is the perovskite solar cells, which is a new and promising family of the photovoltaic applications. Finally, inorganic materials and solution based thin film formation methods using these materials for printable solar cell application is discussed in Part IV.
Book Synopsis DOE-EFRC Center on Nanostructuring for Efficient Energy Conversion (CNEEC). Final Technical Report by :
Download or read book DOE-EFRC Center on Nanostructuring for Efficient Energy Conversion (CNEEC). Final Technical Report written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Stanford University's DOE-EFRC Center on Nanostructuring for Efficient Energy Conversion (CNEEC) made important contributions in advancing our understanding of how nanostructuring of materials can enhance efficiency for solar energy conversion to produce hydrogen fuel and to solve fundamental cross-cutting problems. The overarching hypothesis underlying CNEEC the research projects was to control, synthesize and modify materials at the nanometer scale to increase the efficiency of energy conversion and storage devices and systems. In this pursuit, we emphasized the development of functional nanostructures that are based primarily on earth abundant and inexpensive materials. Efficient and cost effective synthetic routes for hydrogen production from sunlight provides a practical means for clean energy storage as well as an important alternative to fossil fuels. Hydrogen is an environmentally benign fuel that only produces water when burned or oxidized. However, more than 75% of the hydrogen consumed globally is produced commercially by steam reforming of methane that generates not only H2, but also the greenhouse gas CO2. In this regard, photoelectrochemical splitting of water into hydrogen (and oxygen) offers a carbon-free option. Producing hydrogen using renewable energy and widely available non-precious metal-based catalysts not only offers a cost effective process for solar-to-fuel conversion, but also provides great societal and environmental benefits towards mitigating global climate change. As a clean fuel and efficient energy carrier, hydrogen has the potential to provide large-scale energy storage and load leveling especially for intermittent power generation technologies such as wind and solar, and also serve as a carbon-free energy carrier for transportation and portable applications. However, photoelectrochemical splitting of water places strict demands on materials properties. To overcome these challenges, CNEEC developed theoretical and predictive tools as well as synthesis methodologies to control, design and engineer materials at the nanoscale for efficient conversion of sunlight into hydrogen via photoelectrochemical splitting of water. Since this involves developing photoelectrodes that not only capture and absorb photons efficiently but also possess high activity to catalyze the water oxidation reaction, our overarching goal has been to manipulate materials at the nanometer scale in order to modify their properties and improve conversion efficiency. Naturally, enhancing catalysis, reducing diffusion length scales for charge and mass transport, and improving photoabsorption and charge collection via nanostructuring increases conversion efficiency and improves device performance. For this, CNEEC assembled a team of researchers across disciplines and institutions who bring their complementary expertise in experimentation, theory, simulation, synthesis and characterization to bear on complex but fundamental issues that cut across not only photoelectrochemical splitting of water but also in many other energy conversion and storage devices. By such a comprehensive multi-disciplinary approach, CNEEC successfully integrated the tools, methodologies and expertise from different disciplines including synthesis and characterization at the nanoscale as well as theory and simulation to guide experimental efforts. Specifically, advanced synthesis, fabrication and characterization methodologies were developed for nanostructuring to optimize light absorption through quantum and optical confinement and improve catalysis through theory-driven and bio-inspired design for improved performance and efficiency in solar energy conversion to hydrogen fuel. Our research helped understand and expand the scientific foundation of the underlying physical and chemical phenomena that can lead to opportunities for high-efficiency, cost-effective energy technologies. For example, we developed nanostructured photoelectrodes that are based on ...
