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Sample records for thin-film solar cells

  1. Thin-film solar cell:

    Metselaar, J.W.; Kuznetsov, V. I.

    1998-01-01

    The invention relates to a thin-film solar cell provided with at least one p-i-n junction comprising at least one p-i junction which is at an angle alpha with that surface of the thin-film solar cell which collects light during operation and at least one i-n junction which is at an angle beta with the light-collecting surface. In this context, the relationships 45 < alpha < 135 degrees and 45 < beta < 135 degrees apply. The invention also relates to a panel provided with a plurality of such t...

  2. Thin film solar cells. The photovoltaic way

    For introduction of photovoltaic energy systems today the crystalline Si solar cells are most widely used. For wide scale use of solar energy in the society the use of thin film solar cells will be dominant. However, the production costs and the efficiency of conversion must change considerably. The state of the art of thin film solar technology and the research performed in the Netherlands and at ECN on thin film solar technology is given. 7 figs., 2 refs

  3. Thin-film solar cells

    The technological status of a-Si, CuInSe2u, CdTe, f-Si and nc-TiO2 solar cells is evaluated according to a new method that was developed together with the NOVEM. Costs per Wp, producibility, environmental and health concerns, efficiency, life expectation, applicability, and resources are evaluated. Weighing of these criteria according to their assumed importance results in a ranking of the expectations towards these technologies. The result of this evaluation is that no real winners or losers can be identified at this stage. a-Si, f-Si, and nc-TiO2 have a somewhat better perspective than CuInSe2 and CdTe. It should be mentioned, however, that the environmental and health aspects were considered to be very important. 11 figs., 16 tabs., 301 refs., 1 appendix

  4. Silicon Thin-Film Solar Cells

    Guy Beaucarne

    2007-12-01

    Full Text Available We review the field of thin-film silicon solar cells with an active layer thickness of a few micrometers. These technologies can potentially lead to low cost through lower material costs than conventional modules, but do not suffer from some critical drawbacks of other thin-film technologies, such as limited supply of basic materials or toxicity of the components. Amorphous Si technology is the oldest and best established thin-film silicon technology. Amorphous silicon is deposited at low temperature with plasma-enhanced chemical vapor deposition (PECVD. In spite of the fundamental limitation of this material due to its disorder and metastability, the technology is now gaining industrial momentum thanks to the entry of equipment manufacturers with experience with large-area PECVD. Microcrystalline Si (also called nanocrystalline Si is a material with crystallites in the nanometer range in an amorphous matrix, and which contains less defects than amorphous silicon. Its lower bandgap makes it particularly appropriate as active material for the bottom cell in tandem and triple junction devices. The combination of an amorphous silicon top cell and a microcrystalline bottom cell has yielded promising results, but much work is needed to implement it on large-area and to limit light-induced degradation. Finally thin-film polysilicon solar cells, with grain size in the micrometer range, has recently emerged as an alternative photovoltaic technology. The layers have a grain size ranging from 1 μm to several tens of microns, and are formed at a temperature ranging from 600 to more than 1000∘C. Solid Phase Crystallization has yielded the best results so far but there has recently been fast progress with seed layer approaches, particularly those using the aluminum-induced crystallization technique.

  5. Polycrystalline thin-film solar cells

    A description of polycrystalline thin-film solar cells (PTFC) based on the historical development would contain the first observations by Becquerel in 1839, the research by Grondhal and Geiger on Cu20 almost one hundred years later and finally the modern story dating from 1954. In that year a single crystal Si cell and a polycrystalline cell, later recognized as a CdS/Cu2S heterojunction, both of 6% efficiency were reported. In this paper the first topic is a description of a generic solar cell; what are those materials and device features which are common to all photovoltaic systems? The special features of thin-film solar cells based on polycrystalline compound semiconductors are examined. The two materials under most active development are the II-VI compound CdTe and the I-III-VI2 chalcopyrite compound, CuInSe2, and in detail their development and prospects for the future are examined. There are some other materials which also form the basis of potential solar cells and these will be briefly reviewed. Finally, the prospects for tandem or multi-junction cells that incorporate polycrystalline semiconductors are discussed. 40 refs, 21 figs, 4 tabs

  6. Thin-film solar cells. Past, present ... and future

    This article traces the history of thin-film solar cells from the early 1950s, to the use of photovoltaic (PV) power supplies in space missions, and finally to the present where PV is now considered as a real option for terrestrial power production and rural electrification. The development of solar cell efficiencies is described, and the development of thin-film efficiencies is compared with that of crystalline silicon wafer-based cells. The market share of thin-film solar modules, and the impact of amorphous modules on the power market are considered. Details are given of early thin-film solar cells, four decades of cadmium-telluride solar cells (1962-2001), modern materials for thin-film solar cells, cells based on amorphous silicon, thin-layer and thin-film approaches based on crystalline silicon, the use of cadmium telluride, cells based on copper-indium-selenide (CIS) and related compounds, and the dye-sensitised cell. Theoretical and technological aspects of thin-film PV are examined, and the transfer of laboratory-scale production to industrial production is explored

  7. Grown Low-Temperature Microcrystalline Silicon Thin Film by VHF PECVD for Thin Films Solar Cell

    Shanglong Peng; Desheng Wang; Fuhua Yang; Zhanguo Wang; Fei Ma

    2015-01-01

    Hydrogenated microcrystalline silicon thin films can be used to fabricate stable thin film solar cell, which were deposited by very high frequency plasma-enhanced chemical vapor deposition at low temperatures (~200C). It has been found that the obtained film presented excellent structural and electrical properties, such as high growth rate and good crystallinity. With the decreasing of silane concentration, the optical gap and the dark conductivity increased, whereas the activation energy de...

  8. Copper zinc tin sulfide-based thin film solar cells

    Ito, Kentaro

    2014-01-01

    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 tox

  9. Broadband back grating design for thin film solar cells

    Janjua, Bilal

    2013-01-01

    In this paper, design based on tapered circular grating structure was studied, to provide broadband enhancement in thin film amorphous silicon solar cells. In comparison to planar structure an absorption enhancement of ~ 7% was realized.

  10. Recent progress in Si thin film technology for solar cells

    Kuwano, Yukinori; Nakano, Shoichi; Tsuda, Shinya

    1991-11-01

    Progress in Si thin film technology 'specifically amorphous Si (a-Si) and polycrystalline Si (poly-Si) thin film' for solar cells is summarized here from fabrication method, material, and structural viewpoints. In addition to a-Si, primary results on poly-Si thin film research are discussed. Various applications for a-Si solar cells are mentioned, and consumer applications and a-Si solar cell photovoltaic systems are introduced. New product developments include see-through solar cells, solar cell roofing tiles, and ultra-light flexible solar cells. As for new systems, air conditioning equipment powered by solar cells is described. Looking to the future, the proposed GENESIS project is discussed.

  11. Single Source Precursors for Thin Film Solar Cells

    Banger, Kulbinder K.; Hollingsworth, Jennifer A.; Harris, Jerry D.; Cowen, Jonathan; Buhro, William E.; Hepp, Aloysius F.

    2002-01-01

    The development of thin film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution to fabricating solar arrays with high specific power, (W/kg). The use of a polycrystalline chalcopyrite absorber layer for thin film solar cells is considered as the next generation photovoltaic devices. At NASA GRC we have focused on the development of new single source precursors (SSP) and their utility to deposit the chalcopyrite semi-conducting layer (CIS) onto flexible substrates for solar cell fabrication. The syntheses and thermal modulation of SSPs via molecular engineering is described. Thin-film fabrication studies demonstrate the SSPs can be used in a spray CVD (chemical vapor deposition) process, for depositing CIS at reduced temperatures, which display good electrical properties, suitable for PV (photovoltaic) devices.

  12. Mode Splitting for Efficient Plasmoinc Thin-film Solar Cell

    Li, Tong; Jiang, Chun

    2010-01-01

    We propose an efficient plasmonic structure consisting of metal strips and thin-film silicon for solar energy absorption. We numerically demonstrate the absorption enhancement in symmetrical structure based on the mode coupling between the localized plasmonic mode in Ag strip pair and the excited waveguide mode in silicon slab. Then we explore the method of symmetry-breaking to excite the dark modes that can further enhance the absorption ability. We compare our structure with bare thin-film Si solar cell, and results show that the integrated quantum efficiency is improved by nearly 90% in such thin geometry. It is a promising way for the solar cell.

  13. Light trapping in thin film organic solar cells

    Zheng Tang

    2014-10-01

    Full Text Available A major issue in organic solar cells is the poor mobility and recombination of the photogenerated charge carriers. The active layer has to be kept thin to facilitate charge transport and minimize recombination losses. However, optical losses due to inefficient light absorption in the thin active layers can be considerable in organic solar cells. Therefore, light trapping schemes are critically important for efficient organic solar cells. Traditional light trapping schemes for thick solar cells need to be modified for organic thin film solar cells in which coherent optics and wave effects play a significant role. In this review, we discuss the light trapping schemes for organic thin film solar cells, which includes geometric engineering of the structure of the solar cell at the micro and nanoscale, plasmonic structures, and more.

  14. Development of A Thin Film Crystalline Silicon Solar Cell

    A new design for a single junction, thin film Si solar cell is presented. The cell design is compatible with low-temperature processing required for the use of a low-cost glass substrate, and includes effective light trapping and impurity gettering. Elements of essential process steps are discussed

  15. Thin Film Solar Cells and their Optical Properties

    Stanislav Jurecka

    2006-01-01

    Full Text Available In this work we report on the optical parameters of the semiconductor thin film for solar cell applications determination. The method is based on the dynamical modeling of the spectral reflectance function combined with the stochastic optimization of the initial reflectance model estimation. The spectral dependency of the thin film optical parameters computations is based on the optical transitions modeling. The combination of the dynamical modeling and the stochastic optimization of the initial theoretical model estimation enable comfortable analysis of the spectral dependencies of the optical parameters and incorporation of the microstructure effects on the solar cell properties. The results of the optical parameters ofthe i-a-Si thin film determination are presented.

  16. Photon upconversion for thin film solar cells

    Wild, J.

    2012-01-01

    In this research one of the many possible methods to increase the efficiency of solar cells is described. The method investigated is based on adapting the solar light in such a way that the solar cell can convert more light into electricity. The part of the solar spectrum that is adapted is the part that cannot be absorbed by the solar cells, because the photon energy is too low. This conversion of light is done by so called upconversion, which means that lower energy photons are converted in...

  17. Plasmonic versus dielectric enhancement in thin-film solar cells

    Dühring, Maria Bayard; Mortensen, N. Asger; Sigmund, Ole

    2012-01-01

    Several studies have indicated that broadband absorption of thin-film solar cells can be enhanced by use of surface-plasmon induced resonances of metallic parts like strips or particles. The metallic parts may create localized modes or scatter incoming light to increase absorption in thin...

  18. Testing and failure analysis of thin film solar cells

    Boit, Christian [University of Technology, Berlin (Germany); PVcomB Competence Centre Thin-Film- and Nanotechnology for Photovoltaics, Berlin (Germany); Boostandoost, Mahyar; Glowacki, Arkadiusz [University of Technology, Berlin (Germany); Friedrich, Felice [PVcomB Competence Centre Thin-Film- and Nanotechnology for Photovoltaics, Berlin (Germany); University of Technology, Berlin (Germany)

    2011-10-15

    Elements of a systematic concept for test, characterization and analysis of thin film solar cells is discussed that is based on application and comparison of respective techniques in the world of micro- and nanoelectronic technologies, Starting with test and reliability issues, in depth electrical characterization like activation energy analysis from reverse dark currents, is presented. Analysis techniques that belong to the concept require electrically active devices and include all aspects of luminescence and stimulation. A key topic in electronic devices, Focused Ion Beam based Device or Circuit Edit, is also evaluated for application in thin film photovoltaics. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Thin-film crystalline silicon solar cells

    Brendel, Rolf

    2011-01-01

    This introduction to the physics of silicon solar cells focuses on thin cells, while reviewing and discussing the current status of the important technology. An analysis of the spectral quantum efficiency of thin solar cells is given as well as a full set of analytical models. This is the first comprehensive treatment of light trapping techniques for the enhancement of the optical absorption in thin silicon films.

  20. Polycrystalline thin-film solar cells and modules

    Ullal, H.S.; Stone, J.L.; Zweibel, K.; Surek, T.; Mitchell, R.L.

    1991-12-01

    This paper describes the recent technological advances in polycrystalline thin-film solar cells and modules. Three thin film materials, namely, cadmium telluride (CdTe), copper indium diselenide (CuInSe{sub 2}, CIS) and silicon films (Si-films) have made substantial technical progress, both in device and module performance. Early stability results for modules tested outdoors by various groups worldwide are also encouraging. The major global players actively involved in the development of the these technologies are discussed. Technical issues related to these materials are elucidated. Three 20-kW polycrystalline thin-film demonstration photovoltaic (PV) systems are expected to be installed in Davis, CA in 1992 as part of the Photovoltaics for Utility-Scale Applications (PVUSA) project. This is a joint project between the US Department of Energy (DOE), Pacific Gas and Electric (PG&E), Electric Power Research Institute (EPRI), California Energy Commission (CEC), and a utility consortium.

  1. Thin-film silicon solar cell technology

    Shah, A. V.; Schade, H.; Vaněček, Milan; Meier, J.; Vallat-Sauvain, E.; Wyrsch, N.; Kroll, U.; Droz, C.; Bailat, J.

    2004-01-01

    Roč. 12, - (2004), s. 113-142. ISSN 1062-7995 R&D Projects: GA MŽP SN/320/11/03 Institutional research plan: CEZ:AV0Z1010914 Keywords : thin-film silicon modules * hydrogen erated amorphous silicon(a-Si:H) * hydrogen erated microcrystalline (ćc-Si:H) * transparent conductive oxydes(TCOs) * building-integrated photovoltaics(BIPV) Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.196, year: 2004

  2. Metal nanoparticles for thin film solar cells

    Gritti, Claudia

    infrared wavelength region longer than 800 nm accounts for ∼40% of the entire solar energy observed on Earth, and only a few solar cells can efficiently convert solar energy with such a long wavelength. The goal of this work is the harvesting of these NIR photons in order to increase the solar cells...... with modelling; and electroless plating, to grow silver nanocrystals with a cheap technology, producing random distribution of particles. These techniques are studied and optimized aiming to obtain NPs patterns of different size, periodicity and density on the substrates required for the incorporation...... non-regularity in the shape of the NPs: truncated cones with varying bottom and top radius. The difference in shape causes broadening of the resonance peak (as dimostrated by simulations). Electroless plating is a technique, based on chemical reactions, which makes use, in the process chosen for this...

  3. Buried contact multijunction thin film silicon solar cell

    Green, M. [Univ. of New South Wales, Sydney (Australia)

    1995-08-01

    In early 1994, the Center for Photovoltaic Devices and Systems announced the filing of patent applications on an improved silicon thin film photovoltaic module approach. With material costs estimated to be about 20 times lower than those in present silicon solar cell modules along with other production advantages, this technology appears likely to make low cost, high performance solar modules available for the first time. This paper describes steps involved in making a module and module performance.

  4. Polymer Substrates For Lightweight, Thin-Film Solar Cells

    Lewis, Carol R.

    1993-01-01

    Substrates survive high deposition temperatures. High-temperature-resistant polymers candidate materials for use as substrates of lightweight, flexible, radiation-resistant solar photovoltaic cells. According to proposal, thin films of copper indium diselenide or cadmium telluride deposited on substrates to serve as active semiconductor layers of cells, parts of photovoltaic power arrays having exceptionally high power-to-weight ratios. Flexibility of cells exploited to make arrays rolled up for storage.

  5. Large Area Thin Film Silicon: Synergy between Displays and Solar Cells

    Schropp, R. E. I.

    2012-01-01

    Thin-film silicon technology has changed our society, owing to the rapid advance of its two major application fields in communication (thin-film displays) and sustainable energy (thin-film solar cells). Throughout its development, advances in these application fields have always benefitted each other. In the 1980s, display technology benefitted from the know-how on plasma deposition and equipment intended for solar cells. In the 2000s, thin-film solar technology benefitted from the scaled-up ...

  6. Crystalline silicon thin-film solar cells on ceramic substrates

    Rehman, Atteq Ur; Lee, Sang Hee; Lee, Soo Hong

    2015-03-01

    We provide a review and analysis of research on crystalline silicon thin-film solar cells (CSiTFSCs) on ceramic substrates. The use of foreign substrates (non-silicon materials) for the processing of crystalline silicon solar cells could potentially decrease solar-grade silicon consumption and significantly reduce module costs. In order to enhance the efficiency potential of CSiTFSCs on ceramic substrates, high-temperature silicon film deposition is favored. High-quality electronic-grade silicon films are intended to be deposited at higher temperature as it can help increase both deposition rates and grain sizes. The potential low-cost ceramic substrates have some major restrictions in terms of cell processing technology at high temperatures. In this paper, an overview of the research on thin-film solar-cell technologies on ceramic substrates is presented. Major processing steps for CSiTFSC such as substrate/intermediate layer requirements and silicon thin-film deposition at high temperatures will be discussed. So far, devices have been demonstrated with efficiencies up to 13.4% on graphite, 8.2% on mullite, and 9.4% on silicon nitride (Si3N4) ceramic substrates. [Figure not available: see fulltext.

  7. Light-Induced Degradation of Thin Film Silicon Solar Cells

    Hamelmann, F. U.; Weicht, J. A.; Behrens, G.

    2016-02-01

    Silicon-wafer based solar cells are still domination the market for photovoltaic energy conversion. However, most of the silicon is used only for mechanical stability, while only a small percentage of the material is needed for the light absorption. Thin film silicon technology reduces the material demand to just some hundred nanometer thickness. But even in a tandem stack (amorphous and microcrystalline silicon) the efficiencies are lower, and light-induced degradation is an important issue. The established standard tests for characterisation are not precise enough to predict the performance of thin film silicon solar cells under real conditions, since many factors do have an influence on the degradation. We will show some results of laboratory and outdoor measurements that we are going to use as a base for advanced modelling and simulation methods.

  8. Thin-Film Technology in Intermediate Band Solar Cells: Advanced Concepts for Chalcopyrite Solar Cells

    Marrn, David Fuertes

    Combining the two key factors of high performance and low cost into a single solar cell is the major challenge of research on photovoltaics. It is not easy to conceive a practical approach to such a device if not based on thin-film technology. Yet, it appears equally clear that current thin-film solar cells must upgrade their performance by some means in order to meet satisfactory energy conversion efficiencies. The incorporation of novel photovoltaic concepts, particularly the intermediate band solar cell, into thin-film technologies is expected to cross-fertilize both fields. In this chapter, we will outline the potential benefits ofthin-film intermediate band solar cells (TF-IBSC) and describe two different approaches toward its practical implementation. Particular attention will be devoted to devices based on chalcopyrite absorbers, currently leading the efficiency records of thin-film solar cells, and characterized by material properties well suited for this purpose.

  9. Elongated Nanostructures for Radial Junction Thin Film Solar Cells

    Kuang, Y

    2014-01-01

    In solar cell technology, the current trend is to thin down the active absorber layer. The main advantage of a thinner absorber layer primarily is the reduced consumption of material and energy during production, but also the increased production rates and lower cost. While this is of interest to all photovoltaic technologies, for thin-film silicon technology thinning down the absorber layer is of crucial importance since both the device throughput of vacuum deposition systems and the stabili...

  10. Polycrystalline silicon on glass for thin-film solar cells

    Green, Martin A.

    2009-07-01

    Although most solar cell modules to date have been based on crystalline or polycrystalline wafers, these may be too material intensive and hence always too expensive to reach the very low costs required for large-scale impact of photovoltaics on the energy scene. Polycrystalline silicon on glass (CSG) solar cell technology was developed to address this difficulty as well as perceived fundamental difficulties with other thin-film technologies. The aim was to combine the advantages of standard silicon wafer-based technology, namely ruggedness, durability, good electronic properties and environmental soundness with the advantages of thin-films, specifically low material use, large monolithic construction and a desirable glass superstrate configuration. The challenge has been to match the different preferred processing temperatures of silicon and glass and to obtain strong solar absorption in notoriously weakly-absorbing silicon of only 1-2 micron thickness. A rugged, durable silicon thin-film technology has been developed with amongst the lowest manufacturing cost of these contenders and confirmed efficiency for small pilot line modules already in the 10-11% energy conversion efficiency range, on the path to 12-13%.

  11. Laser annealing of thin film polycrystalline silicon solar cell

    Chowdhury A.

    2013-11-01

    Full Text Available Performances of thin film polycrystalline silicon solar cell grown on glass substrate, using solid phase crystallization of amorphous silicon can be limited by low dopant activation and high density of defects. Here, we investigate line shaped laser induced thermal annealing to passivate some of these defects in the sub-melt regime. Effect of laser power and scan speed on the open circuit voltage of the polysilicon solar cells is reported. The processing temperature was measured by thermal imaging camera. Enhancement of the open circuit voltage as high as 210% is achieved using this method. The results are discussed.

  12. Method for producing thin-film multilayer solar cells

    Rampino, Stefano; Gilioli, Edmondo; Bissoli, Francesco; Pattini, Francesco

    2010-01-01

    Description: A method for manufacturing high-quality thin film solar cells entirely by the Pulsed Electron Deposition (PED) is presented. The solar cell is a multi-layer architecture composed with an absorber layer with a chalcopyrite structure and the general composition Cu (In, Ga, Al) (Se, S)2 or CIGASS, deposited on a metallic substrate, that is the lower electrical contact or "back contact", by one or more buffer layer(s) and a layer acting as an electrical contact or the higher "top con...

  13. CdS/CdTe thin film solar cells

    Ikegami, S.; Nakayama, N.; Matsumoto, H.; Yamaguchi, K.; Uda, H.; Taniguchi, H.; Yoshida, M.; Yamashita, T.

    1978-04-01

    The fabriation methods for low cost and highly efficient CdS/CdTe solar cells were investigated. A cell, prepared by epitaxial growth of CdS on a p-type CdTe single crystal, exhibited a solar conversion efficiency of 11.7% for the active area (0.51 cm/sup 2/) when illuminated by sunlight (68mW/cm/sup 2/). On the basis of this result, two types of thin-film solar cells were fabricated. One was CdS (made by chemical bath deposition)/CdTe (made by evaporation), and the other was CdS/CdTe (both made by sintering after printing). Efficiencies of more than 8% were attained in both thin-film solar cells (with active areas of approx. 1cm/sup 2/). These results suggest that practically useful solar cells can be manufactured from CdS/CdTe junction, though further investigations are necessary to obtain large-area cells.

  14. Thin film solar cells from earth abundant materials growth and characterization of Cu2(ZnSn)(SSe)4 thin films and their solar cells

    Kodigala, Subba Ramaiah

    2013-01-01

    The fundamental concept of the book is to explain how to make thin film solar cells from the abundant solar energy materials by low cost. The proper and optimized growth conditions are very essential while sandwiching thin films to make solar cell otherwise secondary phases play a role to undermine the working function of solar cells. The book illustrates growth and characterization of Cu2ZnSn(S1-xSex)4 thin film absorbers and their solar cells. The fabrication process of absorber layers by either vacuum or non-vacuum process is readily elaborated in the book, which helps for further developm

  15. Electrical, morphological and structural properties of RF magnetron sputtered Mo thin films for application in thin film photovoltaic solar cells

    Zoppi, Guillaume; Beattie, Neil; Major, Jonathan; Miles, Robert; Forbes, Ian

    2011-01-01

    Molybdenum (Mo) thin films were deposited using radio frequency magnetron sputtering, for application as a metal back contact material in substrate configuration thin film solar cells. The variations of the electrical, morphological, and structural properties of the deposited films with sputtering pressure, sputtering power and post-deposition annealing were determined. The electrical conductivity of the Mo films was found to increase with decreasing sputtering pressure and increasing spu...

  16. New 3-dimensional nanostructured thin film silicon solar cells

    Vaněček, Milan; Neykova, Neda; Babchenko, Oleg; Purkrt, Adam; Poruba, Aleš; Remeš, Zdeněk; Holovský, Jakub; Hruška, Karel; Meier, J.; Kroll, U.

    München : WIP- Renewable energies, 2010, s. 2763-2766. ISBN 3-936338-26-4. [European Photovoltaic Solar Energy Conference /25./ and World Conference on Photovoltaic Energy Conversion /5./. Valencia (ES), 06.09.2010-10.09.2010] R&D Projects: GA MŠk(CZ) 7E09057 EU Projects: European Commission(XE) 214134 - N2P Institutional research plan: CEZ:AV0Z10100521 Keywords : thin film solar cells, * TCO transparent conductive oxides * a-Si * high stable efficiency, * ZnO Subject RIV: BM - Solid Matter Physics ; Magnetism

  17. Methods for fabricating thin film III-V compound solar cell

    Pan, Noren; Hillier, Glen; Vu, Duy Phach; Tatavarti, Rao; Youtsey, Christopher; McCallum, David; Martin, Genevieve

    2011-08-09

    The present invention utilizes epitaxial lift-off in which a sacrificial layer is included in the epitaxial growth between the substrate and a thin film III-V compound solar cell. To provide support for the thin film III-V compound solar cell in absence of the substrate, a backing layer is applied to a surface of the thin film III-V compound solar cell before it is separated from the substrate. To separate the thin film III-V compound solar cell from the substrate, the sacrificial layer is removed as part of the epitaxial lift-off. Once the substrate is separated from the thin film III-V compound solar cell, the substrate may then be reused in the formation of another thin film III-V compound solar cell.

  18. Thin Film Solar Cells: Organic, Inorganic and Hybrid

    Dankovich, John

    2004-01-01

    Thin film solar cells are an important developing resource for hundreds of applications including space travel. In addition to being more cost effective than traditional single crystal silicon cells, thin film multi-crystaline cells are plastic and light weight. The plasticity of the cells allows for whole solar panels to be rolled out from reams. Organic layers are being investigated in order to increase the efficiency of the cells to create an organic / inorganic hybrid cell. The main focus of the group is a thin film inorganic cell made with the absorber CuInS2. So far the group has been successful in creating the layer from a single-source precursor. They also use a unique method of film deposition called chemical vapor deposition for this. The general makeup of the cell is a molybdenum back contact with the CuInS2 layer, then CdS, ZnO and aluminum top contacts. While working cells have been produced, the efficiency so far has been low. Along with quantum dot fabrication the side project of this that is currently being studied is adding a polymer layer to increase efficiency. The polymer that we are using is P3OT (Poly(3-octylthiopene-2,5-diyll), retroregular). Before (and if) it is added to the cell, it must be understood in itself. To do this simple diodes are being constructed to begin to look at its behavior. The P3OT is spin coated onto indium tin oxide and silver or aluminum contacts are added. This method is being studied in order to find the optimal thickness of the layer as well as other important considerations that may later affect the composition of the finished solar cell. Because the sun is the most abundant renewable, energy source that we have, it is important to learn how to harness that energy and begin to move away from our other depleted non-renewable energy sources. While traditional silicon cells currently create electricity at relatively high efficiencies, they have drawbacks such as weight and rigidness that make them unattractive especially for space applications. Thin film photovoltaics have the potential to alleviate these problems and create a cheap and efficient way to harness the power of the sun.

  19. Silver Nanoparticle Enhanced Freestanding Thin-Film Silicon Solar Cells

    Winans, Joshua David

    As the supply of fossil fuels diminishes in quantity the demand for alternative energy sources will consistently increase. Solar cells are an environmentally friendly and proven technology that suffer in sales due to a large upfront cost. In order to help facilitate the transition from fossil fuels to photovoltaics, module costs must be reduced to prices well below $1/Watt. Thin-film solar cells are more affordable because of the reduced materials costs, but lower in efficiency because less light is absorbed before passing through the cell. Silver nanoparticles placed at the front surface of the solar cell absorb and reradiate the energy of the light in ways such that more of the light ends being captured by the silicon. Silver nanoparticles can do this because they have free electron clouds that can take on the energy of an incident photon through collective action. This bulk action of the electrons is called a plasmon. This work begins by discussing the economics driving the need for reduced material use, and the pros and cons of taking this step. Next, the fundamental theory of light-matter interaction is briefly described followed by an introduction to the study of plasmonics. Following that we discuss a traditional method of silver nanoparticle formation and the initial experimental studies of their effects on the ability of thin-film silicon to absorb light. Then, Finite-Difference Time-Domain simulation software is used to simulate the effects of nanoparticle morphology and size on the scattering of light at the surface of the thin-film.

  20. Development of CIGS2 thin film solar cells

    Research and development of CuIn1-xGa xSe2-yS y (CIGSS) thin-film solar cells on ultralightweight flexible metallic foil substrates is being carried out at FSEC PV Materials Lab for space applications. Earlier, the substrate size was limited to 3 cm x 2.5 cm. Large-area sputtering systems and scrubber for hydrogen selenide and sulfide have been designed and constructed for preparation of CIGSS thin-films on large (15 cm x 10 cm) substrates. A selenization/sulfurization furnace donated by Shell (formerly Siemens) Solar has also been refurbished and upgraded. The sputtering target assembly design was modified for proper clamping of targets and effective cooling. A new design of the magnetic assembly for large-area magnetron sputtering sources was implemented so as to achieve uniform deposition on large area. Lightweight stainless steel foil and ultralightweight titanium foil substrates were utilized to increase the specific power of solar cells. Sol-gel derived SiO2 layers were coated on titanium foil by dip coating method. Deposition parameters for the preparation of molybdenum back contact layers were optimized so as to minimize the residual stress as well as reaction with H2S. Presently large (15 cm x 10 cm) CuIn1-xGa xS2 (CIGS2) thin film solar cells are being prepared on Mo-coated titanium and stainless steel foil by sulfurization of CuGa/In metallic precursors in diluted Ar:H2S(4%). Heterojunction partner CdS layers are deposited by chemical bath deposition. The regeneration sequence of ZnO/ZnO:Al targets was optimized for obtaining consistently good-quality, transparent and conducting ZnO/ZnO:Al bilayer by RF magnetron-sputter deposition. Excellent facilities at FSEC PV Materials Lab are one of its kinds and could serve as a nucleus of a small pilot plant for CIGSS thin film solar cell fabrication

  1. Thin-film intermediate band chalcopyrite solar cells

    Chalcopyrite-based solar cells currently lead the efficiency tables of thin-film photovoltaic technologies. Further improvements are foreseen upon implementation of an intermediate band in the absorber layers. We present a theoretical analysis of the efficiency limit for this type of device as a function of factors such as the gap of the host, the relative position of the intermediate band with respect to the band edge and the level of light concentration used as illumination. We have also considered the impact of non-idealities on the performance of the device, particularly the effect of electronic losses related to non-radiative recombination

  2. Chemically Deposited Thin-Film Solar Cell Materials

    Raffaelle, R.; Junek, W.; Gorse, J.; Thompson, T.; Harris, J.; Hehemann, D.; Hepp, A.; Rybicki, G.

    2005-01-01

    We have been working on the development of thin film photovoltaic solar cell materials that can be produced entirely by wet chemical methods on low-cost flexible substrates. P-type copper indium diselenide (CIS) absorber layers have been deposited via electrochemical deposition. Similar techniques have also allowed us to incorporate both Ga and S into the CIS structure, in order to increase its optical bandgap. The ability to deposit similar absorber layers with a variety of bandgaps is essential to our efforts to develop a multi-junction thin-film solar cell. Chemical bath deposition methods were used to deposit a cadmium sulfide (CdS) buffer layers on our CIS-based absorber layers. Window contacts were made to these CdS/CIS junctions by the electrodeposition of zinc oxide (ZnO). Structural and elemental determinations of the individual ZnO, CdS and CIS-based films via transmission spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy and energy dispersive spectroscopy will be presented. The electrical characterization of the resulting devices will be discussed.

  3. 2D modelling of polycrystalline silicon thin film solar cells

    Leendertz Caspar

    2013-07-01

    Full Text Available The influence of grain boundary (GB properties on device parameters of polycrystalline silicon (poly-Si thin film solar cells is investigated by two-dimensional device simulation. A realistic poly-Si thin film model cell composed of antireflection layer, (n+-type emitter, thick p-type absorber, and (p+-type back surface field was created. The absorber consists of a low-defect crystalline Si grain with an adjacent highly defective grain boundary layer. The performances of a reference cell without GB, one with n-type and one with p-type GB, respectively, are compared. The doping concentration and defect density at the GB are varied. It is shown that the impact of the grain boundary on the poly-Si cell is twofold: a local potential barrier is created at the GB, and a part of the photogenerated current flows within the GB. Regarding the cell performance, a highly doped n-type GB is less critical in terms of the cell’s short circuit current than a highly doped p-type GB, but more detrimental in terms of the cell’s open circuit voltage and fill factor.

  4. Enhanced quantum efficiency of amorphous silicon thin film solar cells with the inclusion of a rear-reflector thin film

    We investigated the growth mechanism of amorphous silicon thin films by implementing hot-wire chemical vapor deposition and fabricated thin film solar cell devices. The fabricated cells showed efficiencies of 7.5 and 8.6% for the samples without and with the rear-reflector decomposed by sputtering, respectively. The rear-reflector enhances the quantum efficiency in the infrared spectral region from 550 to 750?nm. The more stable quantum efficiency of the sample with the inclusion of a rear-reflector than the sample without the rear-reflector due to the bias effect is related to the enhancement of the short circuit current

  5. Commercial Development Of Ovonic Thin Film Solar Cells

    Ovshinsky, Stanford R.

    1983-09-01

    One square foot Ovonic amorphous photovoltaic devices are already in commercial production and are manufactured through a continuous web process. The next levels of commercialization required to achieve a large-volume power market will be discussed, and the device specifications correlated with the chemical and electronic properties of the materials that we are developing to achieve even higher efficiencies. It has been long considered a utopian dream to harness the energy of the sun to create electricity that would be competitive in cost to that produced from the conventional sources of energy such as oil, gas, and uranium. The impact on our society of stand-alone power generators without moving parts using the continually available, ubiquitous energy of the sun could certainly lead to a new age with consequences comparable to the first introduction of electricity which greatly accelerated the Industrial Revolution. Low cost, nonpolluting energy not dependent upon or limited by transmission costs could again make DC electricity a realistic option. The relatively young field of photovoltaics suffers from certain dogmas that are just now being questioned. For example, it is thought by many that solar cells utilizing crys-talline materials have inherently higher efficiencies than those using amorphous materials, and that somehow crystalline solar cells, whether fabricated from single crystals or polycrystalline material, in round or rectangular geometries, grown from the melt or by a rib-bon process, can be reduced in cost sufficiently that the economics become attractive enough for large-scale terrestrial generation of power. In this paper, we shall show that amorphous materials can have much higher efficiencies than do crystalline and that the answer to our power generation needs lies not in crystalline but in amorphous technology. At Energy Conversion Devices, Inc. (ECD), we have designed and built a production machine (described by my colleague, Dr. Izu, in a subsequent paper) which has clearly demonstrated that the basic barrier to low-cost production has been broken through and that one can now speak realistically of delivering power directly from the sun for under a dollar per peak watt merely by making larger versions of this basic continuous web, large-area thin-film machine. We have made one square foot amorphous silicon alloy PIN devices with conversion efficiencies in the range of 7%, and in the laboratory, we have reported smaller area PIN de-vices in the 10% conversion efficiency range. In addition, much higher energy conversion efficiencies can be obtained within the same process by using multi-cell layered or tandem thin-film solar cell structures (see Figure 1). These devices exhibit enhanced efficiency by utilizing a wider range of the solar spectrum. Since the theoretical maximum efficiency for multi-cell structures is over 60%, one can certainly realistically anticipate the pro-duction of thin-film amorphous photovoltaic devices with efficiencies as high as 30%. Our production device is already a two-cell tandem, as we have solved not only the problems of interfacing the individual cell components but also the difficulties associated with a one foot square format deposited on a continuous web. Figure 2 shows a continuous roll of Ovonic solar cells. Realistic calculations for a three-cell tandem thin-film device using amorphous semiconductor alloys with 1.8eV, 1.5eV, and 1.0eV optical band gaps indicate that solar energy conversion efficiencies of 20-30% can be achieved.

  6. Large-Area Thin-Film Silicon: Synergy between Displays and Solar Cells

    Schropp, Ruud E. I.

    2012-03-01

    Thin-film silicon technology has changed our society, owing to the rapid advance of its two major application fields in communication (thin-film displays) and sustainable energy (thin-film solar cells). Throughout its development, advances in these application fields have always benefitted each other. In the 1980s, display technology benefitted from the know-how on plasma deposition and equipment intended for solar cells. In the 2000s, thin-film solar technology benefitted from the scaled-up versions of plasma deposition equipment, and presently Gen5 or Gen5.5 is the most commonly used size for thin-film solar modules. Scaling has always been the major cost driver for displays. For solar cells, the cost per installed watt is another important factor, and therefore primary attention for sustained growth in photovoltaics should be given to cell efficiency.

  7. Molecular solution processing of metal chalcogenide thin film solar cells

    Yang, Wenbing

    The barrier to utilize solar generated electricity mainly comes from their higher cost relative to fossil fuels. However, innovations with new materials and processing techniques can potentially make cost effective photovoltaics. One such strategy is to develop solution processed photovoltaics which avoid the expensive vacuum processing required by traditional solar cells. The dissertation is mainly focused on two absorber material system for thin film solar cells: chalcopyrite CuIn(S,Se)2 (CISS) and kesterite Cu2ZnSn(S,Se) 4 organized in chronological order. Chalcopyrite CISS is a very promising material. It has been demonstrated to achieve the highest efficiency among thin film solar cells. Scaled-up industry production at present has reached the giga-watt per year level. The process however mainly relies on vacuum systems which account for a significant percentage of the manufacturing cost. In the first section of this dissertation, hydrazine based solution processed CISS has been explored. The focus of the research involves the procedures to fabricate devices from solution. The topics covered in Chapter 2 include: precursor solution synthesis with a focus on understanding the solution chemistry, CISS absorber formation from precursor, properties modification toward favorable device performance, and device structure innovation toward tandem device. For photovoltaics to have a significant impact toward meeting energy demands, the annual production capability needs to be on TW-level. On such a level, raw materials supply of rare elements (indium for CIS or tellurium for CdTe) will be the bottleneck limiting the scalability. Replacing indium with zinc and tin, earth abundant kesterite CZTS exhibits great potential to reach the goal of TW-level with no limitations on raw material availability. Chapter 3 shows pioneering work towards solution processing of CZTS film at low temperature. The solution processed devices show performances which rival vacuum-based techniques and is partially attributed to the ease in controlling composition and CZTS phase through this technique. Based on this platform, comprehensive characterization on CZTS devices is carried out including solar cells and transistors. Especially defects properties are exploited in Chapter 4 targeting to identify the limiting factors for further improvement on CZTS solar cells efficiency. Finally, molecular structures and precursor solution stability have been explored, potentially to provide a universal approach to process multinary compounds.

  8. Cuinse2 Thin Film For Solar Cell By Flash Evaporation

    A.H. Soepardjo

    2009-11-01

    Full Text Available Deposition of thin films for material solar cell CuInSe2 are relatively simple. In this research mainly focused on the use of flash evaporation method, and the material created can then be characterized by optical and electrical properties. The optical characterization is done by X-ray Diffraction (XRD, Energy Dispersive Spectroscopy (EDS, and transmission and reflection by UV-VIS spectrophotometry. Electrical characterization is done by utilizing the Hall effect equipment. From these characterization, the atomic structure, absorption coefficient, energy gap, material type, composition of each elements and the mobility of CuInSe2 can be measured and determined. During process evaporation were carried out at substrate temperatures the range between 20ºC-415ºC.

  9. Transparent electrode requirements for thin film solar cell modules

    Rowell, Michael W.

    2011-01-01

    The transparent conductor (TC) layer in thin film solar cell modules has a significant impact on the power conversion efficiency. Reflection, absorption, resistive losses and lost active area either from the scribed interconnect region in monolithically integrated modules or from the shadow losses of a metal grid in standard modules typically reduce the efficiency by 10-25%. Here, we perform calculations to show that a competitive TC must have a transparency of at least 90% at a sheet resistance of less than 10 Ω/sq (conductivity/absorptivity ≥ 1 Ω -1) for monolithically integrated modules. For standard modules, losses are much lower and the performance of alternative lower cost TC materials may already be sufficient to replace conducting oxides in this geometry. © 2011 The Royal Society of Chemistry.

  10. Study of back reflectors for thin film silicon solar cells

    In this study, the reflection properties of transparent conductive oxide (TCO) films i.e. aluminum doped zinc oxide (ZnO:Al) and boron doped zinc oxide (ZnO:B) films plus aluminum (Al) films or white polyvinyl butyral (PVB) foils, which are usually used as the combined back reflectors of thin film silicon solar cells, are investigated. Sputtered ZnO:Al films were etched in diluted hydrochloric acid (1%) to achieve rough surface structures while textured ZnO:B films were directly prepared by a low pressure chemical vapor deposition technique. It is found that the rough TCO/Al reflectors show a low total reflection, which is mainly due to the parasitic absorption by the surface plasmons at the rough TCO/Al interfaces as well as the absorption in the TCO films. Differently, the rough TCO/white PVB foil reflectors display a slightly high light reflection regardless of the influence of the rough interface without the excitation of surface plasmons. Thus, the TCO/white PVB foil back reflectors could be a good candidate with respect to light utilization when they are applied in thin film silicon solar cells. - Highlights: White polyvinyl butyral and transparent conductive oxide materials are used. The reflection properties of TCO/Al and TCO/white PVB foil reflectors are studied. The ZnO:Al and ZnO:B films are used as two types of TCO materials. TCO/white PVB foil reflector shows a high reflection compared to TCO/Al reflector

  11. Study of back reflectors for thin film silicon solar cells

    Zhu, H.; Mai, Y. [Baoding Tianwei Solarfilms Co., Ltd., Baoding 071051 (China); Wan, M. [Department of Chemistry and Material Science, Hunan Institute of Humanities, Science and Technology, Loudi 417000 (China); Gao, J.; Wang, Y.; He, T.; Feng, Y.; Yin, J.; Du, J.; Wang, J.; Sun, R. [Baoding Tianwei Solarfilms Co., Ltd., Baoding 071051 (China); Huang, Y., E-mail: y.huang@btw-solarfilms.com [Baoding Tianwei Solarfilms Co., Ltd., Baoding 071051 (China)

    2013-07-31

    In this study, the reflection properties of transparent conductive oxide (TCO) films i.e. aluminum doped zinc oxide (ZnO:Al) and boron doped zinc oxide (ZnO:B) films plus aluminum (Al) films or white polyvinyl butyral (PVB) foils, which are usually used as the combined back reflectors of thin film silicon solar cells, are investigated. Sputtered ZnO:Al films were etched in diluted hydrochloric acid (1%) to achieve rough surface structures while textured ZnO:B films were directly prepared by a low pressure chemical vapor deposition technique. It is found that the rough TCO/Al reflectors show a low total reflection, which is mainly due to the parasitic absorption by the surface plasmons at the rough TCO/Al interfaces as well as the absorption in the TCO films. Differently, the rough TCO/white PVB foil reflectors display a slightly high light reflection regardless of the influence of the rough interface without the excitation of surface plasmons. Thus, the TCO/white PVB foil back reflectors could be a good candidate with respect to light utilization when they are applied in thin film silicon solar cells. - Highlights: • White polyvinyl butyral and transparent conductive oxide materials are used. • The reflection properties of TCO/Al and TCO/white PVB foil reflectors are studied. • The ZnO:Al and ZnO:B films are used as two types of TCO materials. • TCO/white PVB foil reflector shows a high reflection compared to TCO/Al reflector.

  12. Characterization of thin-film silicon materials and solar cells through numerical modeling

    Pieters, B.E.

    2008-01-01

    At present most commercially available solar cells are made of crystalline silicon (c-Si). The disadvantages of crystalline silicon solar cells are the high material cost and energy consumption during production. A cheaper alternative can be found in thin-film silicon solar cells. The thin-film silicon used in this type of solar cells is in a different phase than c-Si and usually alloyed with hydrogen. The most common thin-film silicon phases are hydrogenated amorphous silicon (a-Si:H) and hy...

  13. Amorphous silicon thin films: The ultimate lightweight space solar cell

    Vendura, G. J., Jr.; Kruer, M. A.; Schurig, H. H.; Bianchi, M. A.; Roth, J. A.

    1994-01-01

    Progress is reported with respect to the development of thin film amorphous (alpha-Si) terrestrial solar cells for space applications. Such devices promise to result in very lightweight, low cost, flexible arrays with superior end of life (EOL) performance. Each alpha-Si cell consists of a tandem arrangement of three very thin p-i-n junctions vapor deposited between film electrodes. The thickness of this entire stack is approximately 2.0 microns, resulting in a device of negligible weight, but one that must be mechanically supported for handling and fabrication into arrays. The stack is therefore presently deposited onto a large area (12 by 13 in), rigid, glass superstrate, 40 mil thick, and preliminary space qualification testing of modules so configured is underway. At the same time, a more advanced version is under development in which the thin film stack is transferred from the glass onto a thin (2.0 mil) polymer substrate to create large arrays that are truly flexible and significantly lighter than either the glassed alpha-Si version or present conventional crystalline technologies. In this paper the key processes for such effective transfer are described. In addition, both glassed (rigid) and unglassed (flexible) alpha-Si cells are studied when integrated with various advanced structures to form lightweight systems. EOL predictions are generated for the case of a 1000 W array in a standard, 10 year geosynchronous (GEO) orbit. Specific powers (W/kg), power densities (W/sq m) and total array costs ($/sq ft) are compared.

  14. Amorphous silicon thin films: The ultimate lightweight space solar cell

    Vendura, G. J., Jr.; Kruer, M. A.; Schurig, H. H.; Bianchi, M. A.; Roth, J. A.

    1994-09-01

    Progress is reported with respect to the development of thin film amorphous (alpha-Si) terrestrial solar cells for space applications. Such devices promise to result in very lightweight, low cost, flexible arrays with superior end of life (EOL) performance. Each alpha-Si cell consists of a tandem arrangement of three very thin p-i-n junctions vapor deposited between film electrodes. The thickness of this entire stack is approximately 2.0 microns, resulting in a device of negligible weight, but one that must be mechanically supported for handling and fabrication into arrays. The stack is therefore presently deposited onto a large area (12 by 13 in), rigid, glass superstrate, 40 mil thick, and preliminary space qualification testing of modules so configured is underway. At the same time, a more advanced version is under development in which the thin film stack is transferred from the glass onto a thin (2.0 mil) polymer substrate to create large arrays that are truly flexible and significantly lighter than either the glassed alpha-Si version or present conventional crystalline technologies. In this paper the key processes for such effective transfer are described. In addition, both glassed (rigid) and unglassed (flexible) alpha-Si cells are studied when integrated with various advanced structures to form lightweight systems. EOL predictions are generated for the case of a 1000 W array in a standard, 10 year geosynchronous (GEO) orbit. Specific powers (W/kg), power densities (W/sq m) and total array costs ($/sq ft) are compared.

  15. Impedance spectroscopy of CdTe thin film solar cells

    Impedance Spectroscopy (IS) is a widely used method to analyze dielectric properties of specimen as a function of frequency. Typically this characterization method delivers an equivalent circuit diagram of the device under examination to describe its electrical properties. Traditionally IS is used in coating evaluation, corrosion monitoring and in electrochemistry. During the last years the method became more important also in the field of electrical characterization of solar cells. In our work we use IS for the electrical characterization of thin film CdTe solar cells. The measurement is done at room temperature without illumination in a frequency domain from 20 Hz to 2 MHz. The samples are measured under variable forward bias. The results match insufficiently with the model of two resistor-capacitor circuits in series which is commonly used to describe the p-n junction and the blocking back contact. For better consistency, other models from the literature are used and discussed. From the results a conclusion is drawn about the properties of the solar cell such as the nature of the p-n junction or the performance of the back contact.

  16. Utility of Thin-Film Solar Cells on Flexible Substrates for Space Power

    Dickman, J. E.; Hepp, A. F.; Morel, D. L.; Ferekides, C. S.; Tuttle, J. R.; Hoffman, D. J.; Dhere, N. G.

    2004-01-01

    The thin-film solar cell program at NASA GRC is developing solar cell technologies for space applications which address two critical metrics: specific power (power per unit mass) and launch stowed volume. To be competitive for many space applications, an array using thin film solar cells must significantly increase specific power while reducing stowed volume when compared to the present baseline technology utilizing crystalline solar cells. The NASA GRC program is developing two approaches. Since the vast majority of the mass of a thin film solar cell is in the substrate, a thin film solar cell on a very lightweight flexible substrate (polymer or metal films) is being developed as the first approach. The second approach is the development of multijunction thin film solar cells. Total cell efficiency can be increased by stacking multiple cells having bandgaps tuned to convert the spectrum passing through the upper cells to the lower cells. Once developed, the two approaches will be merged to yield a multijunction, thin film solar cell on a very lightweight, flexible substrate. The ultimate utility of such solar cells in space require the development of monolithic interconnections, lightweight array structures, and ultra-lightweight support and deployment techniques.

  17. Performance evaluation of thin film silicon solar cell based on dual diffraction grating

    Dubey, Raghvendra Sarvjeet; Saravanan, Sigamani; Kalainathan, Sivaperuman

    2014-01-01

    Light-trapping structures are more demanding for optimal light absorption in thin film silicon solar cells. Accordingly, new design engineering of solar cells has been emphasized and found to be effective to achieve improved performance. This paper deals with a design of thin film silicon solar cells and explores the influence of bottom grating and combination of top and bottom (dual) grating as a part of back reflector with a distributed Bragg reflector (DBR). Use of metal layer as a part of...

  18. Charge carrier dynamics in thin film solar cells

    Strothkaemper, Christian

    2013-06-24

    This work investigates the charge carrier dynamics in three different technological approaches within the class of thin film solar cells: radial heterojunctions, the dye solar cell, and microcrystalline CuInSe{sub 2}, focusing on charge transport and separation at the electrode, and the relaxation of photogenerated charge carriers due to recombination and energy dissipation to the phonon system. This work relies mostly on optical-pump terahertz-probe (OPTP) spectroscopy, followed by transient absorption (TA) and two-photon photoemission (2PPE). The charge separation in ZnO-electrode/In{sub 2}S{sub 3}-absorber core/shell nanorods, which represent a model system of a radial heterojunction, is analyzed by OPTP. It is concluded, that the dynamics in the absorber are determined by multiple trapping, which leads to a dispersive charge transport to the electrode that lasts over hundreds of picoseconds. The high trap density on the order of 10{sup 19}/cm{sup 3} is detrimental for the injection yield, which exhibits a decrease with increasing shell thickness. The heterogeneous electron transfer from a series of model dyes into ZnO proceeds on a time-scale of 200 fs. However, the photoconductivity builds up just on a 2-10 ps timescale, and 2PPE reveals that injected electrons are meanwhile localized spatially and energetically at the interface. It is concluded that the injection proceeds through adsorbate induced interface states. This is an important result because the back reaction from long lived interface states can be expected to be much faster than from bulk states. While the charge transport in stoichiometric CuInSe{sub 2} thin films is indicative of free charge carriers, CuInSe{sub 2} with a solar cell grade composition (Cu-poor) exhibits signs of carrier localization. This detrimental effect is attributed to a high density of charged defects and a high degree of compensation, which together create a spatially fluctuating potential that inhibits charge transport. On the other hand, the charge carrier lifetime in Cu-poor CIS is orders of magnitude higher as in stoichiometric CIS. This is explained by assuming that the CuIn antisite is the most effective recombination center.

  19. Photovoltaic solar cell from low-cost thin-film technology

    One of the main hindrances of using solar energy for electrical power supply is the high initial cost. Thin-film technologies hold considerable promise for substantial cost reduction for photovoltaic solar cells. The paper reviews the present state of the most advanced thin-film technologies. Amorphous silicon (a-Si:H) solar cells have surmounted the barrier to mass production. Pilot manufacturing lines are under construction for CdTe thin-film module. Cu(In, Ga)Se2 has reached a record efficiency of 18.8 percent in the laboratory and pilot productions have been announced by various companies

  20. Photovoltaic solar cell from low-cost thin-film technology

    Full text : One of the main hindrances of using solar energy for electrical power supply is the high initial cost. Thin-film technologies hold considerable promise for substantial cost reduction for photovoltaic solar cells. The paper reviews the present state of the most advanced thin-film technologies. Amorphous silicon solar cells have surmounted the barrier to mass production. Pilot manufacturing lines are under construcion for CdTe thin-film module. Cu(In, Ga)Se2 has reached a record efficiency of 18.8 percent in the laboratory and pilot productions have benn announced by various companies

  1. Plasmonic Light Trapping in Thin-Film Solar Cells: Impact of Modeling on Performance Prediction

    Alberto Micco; Marco Pisco; Armando Ricciardi; Mercaldo, Lucia V.; Iurie Usatii; Vera La Ferrara; Paola Delli Veneri; Antonello Cutolo; Andrea Cusano

    2015-01-01

    We present a comparative study on numerical models used to predict the absorption enhancement in thin-film solar cells due to the presence of structured back-reflectors exciting, at specific wavelengths, hybrid plasmonic-photonic resonances. To evaluate the effectiveness of the analyzed models, they have been applied in a case study: starting from a U-shaped textured glass thin-film, µc-Si:H solar cells have been successfully fabricated. The fabricated cells, with different intrinsic layer th...

  2. Cost perspectives of GaAs thin film solar cells

    To become a viable option for grid-connected electricity supply in the Netherlands GaAs thin film solar cell modules should achieve a break-even module cost of ECU 100-170/m2 or ECU 250-350/m2 if social costs are accounted for. The most important bottleneck is formed by the costs of the substrates for epitaxial layer deposition, which are much too high if GaAs or Ge are used as a substrate material. The cost prospects for monocrystalline or semicrystalline silicon substrates appear to be somewhat better (minimum substrate costs of ECU 65/m2) but major technological difficulties still have to be solved for this option. Deposition on low-cost, non-crystalline substrates by means of the grapho-epitaxial method appears even more difficult. The second bottleneck requires that the utilization rate of source gases for Metal Organic Chemical Vapour Deposition (MOCVD) is improved and that their costs are very much reduced. Thirdly, equipment cost of MOCVD reactors will have to become much lower. Finally raw material supplies may become a bottleneck for large-scale application of GaAs cells, especially if GaAs or Ge substrates are used. It is concluded that meeting the cost targets is very difficult but not impossible. It requires major break-through in each of the above areas. 6 refs., 2 tabs

  3. Nanostructured silicon and its application to solar cells, position sensors and thin film transistors

    Martins, Rodrigo Ferro Paiva; Raniero, Leandro; Pereira, Luis; Costa, Daniel; Aguas, Hugo; Pereira, Sonia; Silva, Leonardo; Ferreira, Isabel; Fortunato, Elvira; Goncalves, Alexandra

    2009-01-01

    Abstract This paper reports the performances of small area solar cells, 128 linear integrated position sensitive detector arrays and thin film transistors based on nanostructured silicon thin films produced by plasma enhanced chemical vapour deposition technique, close to the onset of dusty plasma conditions, within the transition region from amorphous to microcrystalline. The small area solar cells produced in a modified single chamber reactor exhibit very good electrical characte...

  4. The Cu2ZnSnSe4 thin films solar cells synthesized by electrodeposition route

    An electrodeposition route for preparing Cu2ZnSnSe4 thin films for thin film solar cell absorber layers is demonstrated. The Cu2ZnSnSe4 thin films are prepared by co-electrodeposition Cu-Zn-Sn metallic precursor and subsequently annealing in element selenium atmosphere. The structure, composition and optical properties of the films were investigated by X-ray diffraction (XRD), Raman spectrometry, energy dispersive spectrometry (EDS) and UV-VIS absorption spectroscopy. The Cu2ZnSnSe4 thin film with high crystalline quality was obtained, the band gap and absorption coefficient were 1.0 eV and 10-4 cm-1, which is quite suitable for solar cells fabrication. A solar cell with the structure of ZnO:Al/i-ZnO/CdS/Cu2ZnSnSe4/Mo/glass was fabricated and achieved an conversion efficiency of 1.7%.

  5. Molybdenum Back-Contact Optimization for CIGS Thin Film Solar Cell

    J.R. Ray

    2011-01-01

    Full Text Available Molybdenum (Mo thin films are most widely used as an ohmic back-contact in the copper indium diselenide (CIS and its alloy copper indium gallium diselenide (CIGS based thin film solar cell. Radio frequency (RF magnetron sputtering system used to deposit Mo thin films on soda lime glass substrate. The deposition was carried out using argon (Ar gas at different Ar controlled (working pressures (1 mTorr to 10 mTorr and at different RF powers (60 W to 100 W. The influence of both the working pressure and the RF power on the Mo thin films was studied by investigating its structural, morphological, electrical, and optical measurements. The results reveal that a stress-free, low-sheet-resistance (~1 Ω/cm2, and reflecting (~ 55 % Mo thin film was observed at 1 mTorr working pressure and 100 W RF power.

  6. Preparation of vanadium diselenide thin films and their application in CdTe solar cells

    Vanadium diselenide thin films were prepared by electron beam evaporation. The properties of vanadium diselenide thin films were investigated using X-ray diffraction, scanning electron microscope, transmission spectra, electrical and Hall measurements. To further investigate the application of vanadium diselenide thin films, device performance in CdTe solar cells with a vanadium diselenide layer was also studied. The results indicate that vanadium diselenide thin films had a stable hexagonal structure after annealing. The thin films were p-type semiconductor materials with the high work function and high carrier concentration. Vanadium diselenide thin films could form a good ohmic contact to CdTe solar cells. Thus, cell performance was greatly improved when introduced a vanadium diselenide buffer layer. - Highlights: • VSe2 was prepared by electron beam evaporation. • VSe2 was a p-type material with the high work function and high carrier concentration. • VSe2 was used as a Cu-free buffer layer in CdTe solar cells. • Performance of CdTe solar cells was improved

  7. Crystalline silicon thin film growth by ECR plasma CVD for solar cells

    This thesis describes the background, motivation and work carried out towards this PhD programme entitled 'Crystalline Silicon Thin Film Growth by ECR Plasma CVD for Solar Cells'. The fundamental principles of silicon solar cells are introduced with a review of silicon thin film and bulk solar cells. The development and prospects for thin film silicon solar cells are described. Some results of a modelling study on thin film single crystalline solar cells are given which has been carried out using a commercially available solar cell simulation package (PC-1D). This is followed by a description of thin film deposition techniques. These include Chemical Vapour Deposition (CVD) and Plasma-Assisted CVD (PACVD). The basic theory and technology of the emerging technique of Electron Cyclotron Resonance (ECR) PACVD, which was used in this research, are introduced and the potential advantages summarised. Some of the basic methods of material and cell characterisation are briefly described, together with the work carried out in this research. The growth by ECR PACVD at temperatures 2 illumination. The best efficiency in the ECR grown structures was 13.76% using an epitaxial emitter. Cell performance was analysed in detail and the factors controlling performance identified by fitting self-consistently the fight and dark current-voltage and spectral response data using PC-1D. Finally, the conclusions for this research and suggestions for further work are outlined. (author)

  8. Sputtered molybdenum thin films and the application in CIGS solar cells

    Zhou, D.; Zhu, H.; Liang, X.; Zhang, C.; Li, Z.; Xu, Y.; Chen, J.; Zhang, L.; Mai, Y.

    2016-01-01

    Molybdenum (Mo) thin films are prepared by magnetron sputtering with different discharge powers and working pressures for the application in Cu(In, Ga)Se2 (CIGS) thin film solar cells as back electrodes. Properties of these Mo thin films are systematically investigated. It is found that the dynamic deposition rate increases with the increasing discharge power while decreases with the increasing working pressure. The highest dynamic deposition rate of 15.1 nm m/min is achieved for the Mo thin film deposited at the discharge power of 1200 W and at the working pressure of 0.15 Pa. The achieved lowest resistivity of 3.7 × 10-5 Ω cm is attributed to the large grains in the compact thin film. The discharge power and working pressure have great influence on the sputtered Mo thin films. High efficiency of 12.5% was achieved for the Cu(In, Ga)Se2 (CIGS) thin film solar cells with Mo electrodes prepared at 1200 W and low working pressures. By further optimizing material and device properties, the conversion efficiency has reached to 15.2%.

  9. Hydrogen passivation of polycrystalline Si thin film solar cells

    Hydrogen passivation is a key process step in the fabrication of polycrystalline Si (poly-Si) thin film solar cells. In this work a parallel plate rf plasma setup was used for the hydrogen passivation treatment. The main topics that have been investigated are (i) the role of plasma parameters (like hydrogen pressure, electrode gap and plasma power), (ii) the dynamics of the hydrogen treatment and (iii) passivation of poly-Si with different material properties. Passivation was characterized by measuring the open-circuit voltage VOC of poly-Si reference samples. Optimum passivation conditions were found by measurements of the breakdown voltage Vbrk of the plasma for different pressures p and electrode gaps d. For each pressure, the best passivation was achieved at a gap d that corresponded to the minimum in Vbrk. Plasma simulations were carried out, which indicate that best VOC corresponds to a minimum in ion energy. VOC was not improved by a larger H flux. Investigations of the passivation dynamic showed that a plasma treatment in the lower temperature range (≤400 C) is slow and takes several hours for the VOC to saturate. Fast passivation can be successfully achieved at elevated temperatures around 500 C to 600 C with a plateau time of 10 min. It was found that prolonged hydrogenation leads to a loss in VOC, which is less pronounced within the observed optimum temperature range (500 C-600 C). Electron beam evaporation has been investigated as an alternative method to fabricate poly-Si absorbers. The material properties have been tuned by alteration of substrate temperature Tdep=200-700 C and were characterized by Raman, ESR and VOC measurements. Largest grains were obtained after solid phase crystallization (SPC) of a-Si, deposited in the temperature range of 300 C. The defect concentration of Si dangling bonds was lowered by passivation by about one order of magnitude. The lowest dangling bond concentration of 2.5.1016 cm-3 after passivation was found for poly-Si with largest grains and coincides with best solar cell results, obtained after rapid thermal annealing and hydrogen passivation. Hydrogen passivation of poly-Si films was successfully achieved with a parallel plate rf H plasma treatment at elevated temperatures around 500 C to 600 C. Yet it seems that treatment induced defect generation causes a loss in VOC with prolonged passivation time and should be minimized. In order to achieve high open circuit voltages larger than 450 mV, in addition to hydrogen passivation, low recombination at the interfaces becomes more and more important. (orig.)

  10. High power impulse magnetron sputtering of CIGS thin films for high efficiency thin film solar cells

    Olejníček, Jiří; Hubička, Zdeněk; Kohout, Michal; Kšírová, Petra; Kment, Štěpán; Brunclíková, Michaela; Čada, Martin; Darveau, S.A.; Exstrom, C.L.

    2014-01-01

    Roč. 1, č. 3 (2014), s. 135-137. ISSN 2336-2626 R&D Projects: GA MŠk LH12045 Institutional support: RVO:68378271 Keywords : CIGS * HiPIMS * emission spectroscopy * thin films * magnetron sputtering Subject RIV: BL - Plasma and Gas Discharge Physics http://fyzika.feld.cvut.cz/misc/ppt/articles/2014/olejnicek.pdf

  11. Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

    Wang Lan; Lin Xianzhong; Ennaoui Ahmed; Wolf Christian; Lux-Steiner Martha Ch.; Klenk Reiner

    2016-01-01

    We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating ...

  12. Indium sulfide thin films as window layer in chemically deposited solar cells

    Indium sulfide (In2S3) thin films have been synthesized by chemical bath deposition technique onto glass substrates using In(NO3)3 as indium precursor and thioacetamide as sulfur source. X-ray diffraction studies have shown that the crystalline state of the as-prepared and the annealed films is β-In2S3. Optical band gap values between 2.27 and 2.41 eV were obtained for these films. The In2S3 thin films are photosensitive with an electrical conductivity value in the range of 10−3–10−7 (Ω cm)−1, depending on the film preparation conditions. We have demonstrated that the In2S3 thin films obtained in this work are suitable candidates to be used as window layer in thin film solar cells. These films were integrated in SnO2:F/In2S3/Sb2S3/PbS/C–Ag solar cell structures, which showed an open circuit voltage of 630 mV and a short circuit current density of 0.6 mA/cm2. - Highlights: • In2S3 thin films were deposited using the Chemical Bath Deposition technique. • A direct energy band gap between 2.41 to 2.27 eV was evaluated for the In2S3 films. • We made chemically deposited solar cells using the In2S3 thin films

  13. Enhanced Efficiency of Light-Trapping Nanoantenna Arrays for Thin Film Solar Cells

    Simovski, Constantin R; Voroshilov, Pavel M; Guzhva, Michael E; Belov, Pavel A; Kivshar, Yuri S

    2013-01-01

    We suggest a novel concept of efficient light-trapping structures for thin-film solar cells based on arrays of planar nanoantennas operating far from plasmonic resonances. The operation principle of our structures relies on the excitation of chessboard-like collective modes of the nanoantenna arrays with the field localized between the neighboring metal elements. We demonstrated theoretically substantial enhancement of solar-cell short-circuit current by the designed light-trapping structure in the whole spectrum range of the solar-cell operation compared to conventional structures employing anti-reflecting coating. Our approach provides a general background for a design of different types of efficient broadband light-trapping structures for thin-film solar-cell technologically compatible with large-area thin-film fabrication techniques.

  14. Poly CdTe thin films solar cells

    Marfaing, Y.

    1982-01-01

    CdTe is potentially one of the most interesting materials for the photovoltaic conversion of solar energy. The width of its forbidden band of 1.5 eV puts it to the maximum of the theoretical yield curve (24%). Its high coefficient of optical absorption in the main band allows the use of thin films (2 to 3 microns). It is appropriate for production of thin polycristalline films with good optical and photoelectrical properties, which is probably due to its ionic character. The goal of the research performed as part of this contract is to determine the optimum conditions for the use of CdTe as photovoltaic converter. The authors think that the virtual efficiency of this material calls for confirmation and evidence provided by a systematic and profound investigation.

  15. Enhanced optical absorption by Ag nanoparticles in a thin film Si solar cell

    Thin film solar cells have the potential to significantly reduce the cost of photovoltaics. Light trapping is crucial to such a thin film silicon solar cell because of a low absorption coefficient due to its indirect band gap. In this paper, we investigate the suitability of surface plasmon resonance Ag nanoparticles for enhancing optical absorption in the thin film solar cell. For evaluating the transmittance capability of Ag nanoparticles and the conventional antireflection film, an enhanced transmittance factor is introduced. We find that under the solar spectrum AM1.5, the transmittance of Ag nanoparticles with radius over 160 nm is equivalent to that of conventional textured antireflection film, and its effect is better than that of the planar antireflection film. The influence of the surrounding medium is also discussed. (physics of gases, plasmas, and electric discharges)

  16. Laser processing for the integrated series connection of thin-film silicon solar cells

    Turan, Bugra

    2016-01-01

    The integrated series connection of solar cells is an essential aspect for thin-film photovoltaic technology. With a series connection a high output voltage of the module is achieved while the output current is kept low. Thus, Ohmic losses in the contact materials are kept low as well. In thin-film silicon solar technology the steps to create the interconnection are commonly done by laser ablation integrated in-between the depositions of the solar cell layer materials. In three steps laser sc...

  17. Hydrogen passivation of polycrystalline Si thin film solar cells

    Gorka, Benjamin

    2010-12-15

    Hydrogen passivation is a key process step in the fabrication of polycrystalline Si (poly-Si) thin film solar cells. In this work a parallel plate rf plasma setup was used for the hydrogen passivation treatment. The main topics that have been investigated are (i) the role of plasma parameters (like hydrogen pressure, electrode gap and plasma power), (ii) the dynamics of the hydrogen treatment and (iii) passivation of poly-Si with different material properties. Passivation was characterized by measuring the open-circuit voltage V{sub OC} of poly-Si reference samples. Optimum passivation conditions were found by measurements of the breakdown voltage V{sub brk} of the plasma for different pressures p and electrode gaps d. For each pressure, the best passivation was achieved at a gap d that corresponded to the minimum in V{sub brk}. Plasma simulations were carried out, which indicate that best V{sub OC} corresponds to a minimum in ion energy. V{sub OC} was not improved by a larger H flux. Investigations of the passivation dynamic showed that a plasma treatment in the lower temperature range ({<=}400 C) is slow and takes several hours for the V{sub OC} to saturate. Fast passivation can be successfully achieved at elevated temperatures around 500 C to 600 C with a plateau time of 10 min. It was found that prolonged hydrogenation leads to a loss in V{sub OC}, which is less pronounced within the observed optimum temperature range (500 C-600 C). Electron beam evaporation has been investigated as an alternative method to fabricate poly-Si absorbers. The material properties have been tuned by alteration of substrate temperature T{sub dep}=200-700 C and were characterized by Raman, ESR and V{sub OC} measurements. Largest grains were obtained after solid phase crystallization (SPC) of a-Si, deposited in the temperature range of 300 C. The defect concentration of Si dangling bonds was lowered by passivation by about one order of magnitude. The lowest dangling bond concentration of 2.5.10{sup 16} cm{sup -3} after passivation was found for poly-Si with largest grains and coincides with best solar cell results, obtained after rapid thermal annealing and hydrogen passivation. Hydrogen passivation of poly-Si films was successfully achieved with a parallel plate rf H plasma treatment at elevated temperatures around 500 C to 600 C. Yet it seems that treatment induced defect generation causes a loss in V{sub OC} with prolonged passivation time and should be minimized. In order to achieve high open circuit voltages larger than 450 mV, in addition to hydrogen passivation, low recombination at the interfaces becomes more and more important. (orig.)

  18. Spray-on Thin Film PV Solar Cells: Advances, Potentials and Challenges

    Morteza Eslamian

    2014-01-01

    Full Text Available The capability to fabricate photovoltaic (PV solar cells on a large scale and at a competitive price is a milestone waiting to be achieved. Currently, such a fabrication method is lacking because the effective methods are either difficult to scale up or expensive due to the necessity for fabrication in a vacuum environment. Nevertheless, for a class of thin film solar cells, in which the solar cell materials can be processed in a solution, up scalable and vacuum-free fabrication techniques can be envisioned. In this context, all or some layers of polymer, dye-sensitized, quantum dot, and copper indium gallium selenide thin film solar cells illustrate some examples that may be processed in solution. The solution-processed materials may be transferred to the substrate by atomizing the solution and carrying the spray droplets to the substrate, a process that will form a thin film after evaporation of the solvent. Spray coating is performed at atmospheric pressure using low cost equipment with a roll-to-roll process capability, making it an attractive fabrication technique, provided that fairly uniform layers with high charge carrier separation and transport capability can be made. In this paper, the feasibility, the recent advances and challenges of fabricating spray-on thin film solar cells, the dynamics of spray and droplet impaction on the substrate, the photo-induced electron transfer in spray-on solar cells, the challenges on characterization and simulation, and the commercialization status of spray-on solar cells are discussed.

  19. Material selection for thin-film solar cells using multiple attribute decision making approach

    This paper presents a material selection approach for selecting absorbent layer material for thin-film solar cells (TFSCs) using multiple attribute decision making (MADM) approach. In this paper, different possible materials for absorbent layer and their properties like band gap, absorption coefficient, diffusion length, thermodynamic compatibility and recombination velocity is taken into consideration and MADM approach is applied to select the best material for thin-film solar cells. It is observed that Copper Indium Gallium Diselinide (CIGS) is the best material for the absorbent layer in thin-film solar cells out of all possible candidates. It was observed that the proposed result is in accordance with the experimental findings thus justifying the validity of the proposed study.

  20. Textured conducting glass by nanosphere lithography for increased light absorption in thin-film solar cells

    Nanoscale surface texturing in thin-film solar cells has been shown to enhance device efficiency by increasing light absorption through reduced reflectance and increased light scattering across a broad range of wavelengths and angles. However, light trapping in the industrial thin-film cells is still sub-optimal and creating optimized nanoscale texture over a large area remains challenging. In this article, we present a well-controlled low-cost process to fabricate a periodic nanocone texture optimized for maximum light absorption in thin-film microcrystalline silicon solar cells. The texture is fabricated using nanosphere lithography with the period controlled by the nanosphere diameter and the texture shape and aspect ratio controlled by the reactive ion etching conditions. Finite-difference time-domain optical simulations are used to optimize the texture in the state-of-the-art microcrystalline cells, and optical absorption measurements show that the same cells fabricated on the optimized nanocone-textured substrates exhibit a relative short-circuit current increase of close to 30% compared to a reference state-of-the-art cell with a randomly textured zinc oxide layer. This nanocone texturing technique is compatible with standard thin-film cell fabrication processes and can also be used for other thin-film cells (CIGS, CdTe, CZTS, etc) to maximize light absorption and minimize layer thickness enabling more efficient carrier collection and lower overall cost. (paper)

  1. Hybrid solar cells using CdS thin films deposited via spray pyrolysis technique

    The paper presents the photovoltaic performance of hybrid solar cells comprising of thin films of cadmium sulphide and poly(3-hexyl)thiophene. Cadmium sulphide thin films were deposited using spray pyrolysis technique. Current-voltage characterizations were performed for cadmium sulphide/poly(3-hexyl)thiophene heterojunctions in dark and under illumination (100 mWcm−2). The best device yields a short circuit current density of 1.54 mA/cm2, an open circuit voltage of 343 mV, and a power conversion efficiency of 0.15%. - Highlights: • Hybrid solar cells were fabricated using CdS and poly(3-hexyl)thiophene. • CdS thin films were grown by spray pyrolysis technique. • The best cell performance was achieved for the 100 nm thick CdS films. • The highest short circuit current was measured as 1.54 mAcm−2 for the best cell

  2. A Review on Development Prospect of CZTS Based Thin Film Solar Cells

    Xiangbo Song; Xu Ji; Ming Li; Weidong Lin; Xi Luo; Hua Zhang

    2014-01-01

    Cu2ZnSnS4 is considered as the ideal absorption layer material in next generation thin film solar cells due to the abundant component elements in the crust being nontoxic and environmentally friendly. This paper summerized the development situation of Cu2ZnSnS4 thin film solar cells and the manufacturing technologies, as well as problems in the manufacturing process. The difficulties for the raw materials preparation, the manufacturing process, and the manufacturing equipment were illustrate...

  3. Design of nanostructured plasmonic back contacts for thin-film silicon solar cells.

    Paetzold, Ulrich W; Moulin, Etienne; Pieters, Bart E; Carius, Reinhard; Rau, Uwe

    2011-11-01

    We report on a plasmonic light-trapping concept based on localized surface plasmon polariton induced light scattering at nanostructured Ag back contacts of thin-film silicon solar cells. The electromagnetic interaction between incident light and localized surface plasmon polariton resonances in nanostructured Ag back contacts was simulated with a three-dimensional numerical solver of Maxwell's equations. Geometrical parameters as well as the embedding material of single and periodic nanostructures on Ag layers were varied. The design of the nanostructures was analyzed regarding their ability to scatter incident light at low optical losses into large angles in the silicon absorber layers of the thin-film silicon solar cells. PMID:22109618

  4. Modulated photonic-crystal structures as broadband back reflectors in thin-film solar cells :

    Krc, J.; Zeman, M.; Luxembourg, S.L.; Topic, M.

    2009-01-01

    A concept of a modulated one-dimensional photonic-crystal (PC) structure is introduced as a back reflector for thin-film solar cells. The structure comprises two PC parts, each consisting of layers of different thicknesses. Using layers of amorphous silicon and amorphous silicon nitride a reflectance close to 100% is achieved over a broad wavelength region (7001300 nm). Based on this concept, a back reflector was designed for thin-film microcrystalline silicon solar cells, using n-doped amor...

  5. Transparent conductive zinc oxide basics and applications in thin film solar cells

    Klein, Andreas; Rech, Bernd

    2008-01-01

    Zinc oxide (ZnO) belongs to the class of transparent conducting oxides which can be used as transparent electrodes in electronic devices or heated windows. In this book the material properties of, the deposition technologies for, and applications of zinc oxide in thin film solar cells are described in a comprehensive manner. Structural, morphological, optical and electronic properties of ZnO are treated in this review. The editors and authors of this book are specialists in deposition, analysis and fabrication of thin-film solar cells and especially of ZnO. This book is intended as an overview and a data collection for students, engineers and scientist.

  6. Effect of Substrate Temperature on CdTe Thin Film Property and Solar Cell Performance

    CAO Sheng, WU Li-Li, FENG Liang-Huan, WANG Wen-Wu, ZHANG Jing-Quan, YU Xiao-Qi, LI Xin-Xin, LI Wei, LI Bing

    2016-02-01

    Full Text Available Vapor transport deposition is an excellent method for preparing large area CdTe thin films with high quality and uniformity. Polycrystalline CdTe thin films were deposited by home-made vapor transport deposition system (VTD. The effects of substrate temperature on the property of CdTe film and the performance of CdTe solar cell were investigated. CdTe thin films were characterized by scanning electron microscope (SEM, X-ray diffraction (XRD, UV-Vis spectrometer, and Hall Effect system. The results show that the CdTe thin films deposited by vapor transport deposition are cubic phase with a preferred orientation in (111 direction. The average grain size increases from 2μm to 6μm and the carrier concentration increases from 1.93×1010 cm –3 to 2.36×1013 cm –3 when the substrate temperature increases from 520 ℃ to 620 ℃. This suggests that high substrate temperature can increase the carrier density significantly due to the suppressed defect recombination. The performance of CdTe thin film solar cells deposited at different substrate temperatures demonstrates that high substrate temperature (610℃ can greatly improve the efficiency, open circuit voltage and fill factor of the solar cells. But the substrate temperature higher than 610℃ will reduce the spectral response of the cells in long wavelength region, which results in the degradation of solar cell performance. The small-area CdTe thin film solar cell without back contact layer deposited at substrate temperature of 610℃ obtains the best conversion efficiency of 11.2%.

  7. Comparing n- and p-type polycrystalline silicon absorbers in thin-film solar cells

    Deckers, J. [imec, Kapeldreef 75, B-3001 Heverlee, Leuven (Belgium); ESAT, KU Leuven, Kardinaal Mercierlaan 94, B-3001 Heverlee, Leuven (Belgium); Bourgeois, E. [Institute for Materials Research (IMO), Hasselt University, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); IMOMEC, IMEC vzw, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); Jivanescu, M. [Department of Physics and Astronomy, University of Leuven, Celestijnenlaan 200D, B-3001 Heverlee, Leuven (Belgium); Abass, A. [Photonics Research Group (INTEC), Ghent University-imec, Sint-Pietersnieuwstraat 41, B-9000 Ghent (Belgium); Van Gestel, D.; Van Nieuwenhuysen, K.; Douhard, B. [imec, Kapeldreef 75, B-3001 Heverlee, Leuven (Belgium); D' Haen, J.; Nesladek, M.; Manca, J. [Institute for Materials Research (IMO), Hasselt University, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); IMOMEC, IMEC vzw, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); Gordon, I.; Bender, H. [imec, Kapeldreef 75, B-3001 Heverlee, Leuven (Belgium); Stesmans, A. [Department of Physics and Astronomy, University of Leuven, Celestijnenlaan 200D, B-3001 Heverlee, Leuven (Belgium); Mertens, R.; Poortmans, J. [imec, Kapeldreef 75, B-3001 Heverlee, Leuven (Belgium); ESAT, KU Leuven, Kardinaal Mercierlaan 94, B-3001 Heverlee, Leuven (Belgium)

    2015-03-31

    We have investigated fine grained polycrystalline silicon thin films grown by direct chemical vapor deposition on oxidized silicon substrates. More specifically, we analyze the influence of the doping type on the properties of this model polycrystalline silicon material. This includes an investigation of defect passivation and benchmarking of minority carrier properties. In our investigation, we use a variety of characterization techniques to probe the properties of the investigated polycrystalline silicon thin films, including Fourier Transform Photoelectron Spectroscopy, Electron Spin Resonance, Conductivity Activation, and Suns-Voc measurements. Amphoteric silicon dangling bond defects are identified as the most prominent defect type present in these layers. They are the primary recombination center in the relatively lowly doped polysilicon thin films at the heart of the current investigation. In contrast with the case of solar cells based on Czochralski silicon or multicrystalline silicon wafers, we conclude that no benefit is found to be associated with the use of n-type dopants over p-type dopants in the active absorber of the investigated polycrystalline silicon thin-film solar cells. - Highlights: • Comparison of n- and p-type absorbers for thin-film poly-Si solar cells • Extensive characterization of the investigated layers' characteristics • Literature review pertaining the use of n-type and p-type dopants in silicon.

  8. Comparing n- and p-type polycrystalline silicon absorbers in thin-film solar cells

    We have investigated fine grained polycrystalline silicon thin films grown by direct chemical vapor deposition on oxidized silicon substrates. More specifically, we analyze the influence of the doping type on the properties of this model polycrystalline silicon material. This includes an investigation of defect passivation and benchmarking of minority carrier properties. In our investigation, we use a variety of characterization techniques to probe the properties of the investigated polycrystalline silicon thin films, including Fourier Transform Photoelectron Spectroscopy, Electron Spin Resonance, Conductivity Activation, and Suns-Voc measurements. Amphoteric silicon dangling bond defects are identified as the most prominent defect type present in these layers. They are the primary recombination center in the relatively lowly doped polysilicon thin films at the heart of the current investigation. In contrast with the case of solar cells based on Czochralski silicon or multicrystalline silicon wafers, we conclude that no benefit is found to be associated with the use of n-type dopants over p-type dopants in the active absorber of the investigated polycrystalline silicon thin-film solar cells. - Highlights: • Comparison of n- and p-type absorbers for thin-film poly-Si solar cells • Extensive characterization of the investigated layers' characteristics • Literature review pertaining the use of n-type and p-type dopants in silicon

  9. Light trapping in thin film organic solar cells

    Zheng Tang; Wolfgang Tress; Olle Ingans

    2014-01-01

    A major issue in organic solar cells is the poor mobility and recombination of the photogenerated charge carriers. The active layer has to be kept thin to facilitate charge transport and minimize recombination losses. However, optical losses due to inefficient light absorption in the thin active layers can be considerable in organic solar cells. Therefore, light trapping schemes are critically important for efficient organic solar cells. Traditional light trapping schemes for thick solar cell...

  10. Spray-on Thin Film PV Solar Cells: Advances, Potentials and Challenges

    Morteza Eslamian

    2014-01-01

    The capability to fabricate photovoltaic (PV) solar cells on a large scale and at a competitive price is a milestone waiting to be achieved. Currently, such a fabrication method is lacking because the effective methods are either difficult to scale up or expensive due to the necessity for fabrication in a vacuum environment. Nevertheless, for a class of thin film solar cells, in which the solar cell materials can be processed in a solution, up scalable and vacuum-free fabrication techniques c...

  11. Effects of Different Parameters In Enhancing The Efficiency of Plasmonic Thin Film Solar Cells

    N.Alekhya Reddy

    2014-09-01

    Full Text Available Efficiency of thin film solar cells are less comparing to thick film solar cells which can be enhanced by utilizing the metal nanoparticles near their localized Plasmon resonance. In this paper, we have reviewed the Plasmon resonance of metallic nanoparticles and its application in solar cell technology. Beside this, we have also reviewed about different parameters which dominate the nanoparticles to increase optical absorption. Thus a cost-effective model has been proposed.

  12. The impact of sodium contamination in tin sulfide thin-film solar cells

    Steinmann, Vera; Brandt, Riley E.; Chakraborty, Rupak; Jaramillo, R.; Young, Matthew; Ofori-Okai, Benjamin K.; Yang, Chuanxi; Polizzotti, Alex; Nelson, Keith A.; Gordon, Roy G.; Buonassisi, Tonio

    2016-02-01

    Through empirical observations, sodium (Na) has been identified as a benign contaminant in some thin-film solar cells. Here, we intentionally contaminate thermally evaporated tin sulfide (SnS) thin-films with sodium and measure the SnS absorber properties and solar cell characteristics. The carrier concentration increases from 2 × 1016 cm-3 to 4.3 × 1017 cm-3 in Na-doped SnS thin-films, when using a 13 nm NaCl seed layer, which is detrimental for SnS photovoltaic applications but could make Na-doped SnS an attractive candidate in thermoelectrics. The observed trend in carrier concentration is in good agreement with density functional theory calculations, which predict an acceptor-type NaSn defect with low formation energy.

  13. Photovoltaic Technology: The Case for Thin-Film Solar Cells

    Shah, Arvind; Torres, P.; Tscharner, Reto; Wyrsch, N.; Keppner H

    2013-01-01

    The advantages and limitations of photovoltaic solar modules for energy generation are reviewed with their operation principles and physical efficiency limits. Although the main materials currently used or investigated and the associated fabrication technologies are individually described, emphasis is on silicon-based solar cells. Wafer-based crystalline silicon solar modules dominate in terms of production, but amorphous silicon solar cells have the potential to undercut costs owing, for exa...

  14. Hydrogen and Surface Passivation of Thin-film Crystalline Silicon Solar Cells on Graphite Substrates

    Li, Da

    2015-01-01

    Silicon substrates can be replaced by foreign substrates for crystalline silicon thin-film (CSiTF) solar cells, which is an effective strategy to reduce both the cost of cell production and the consumption of silicon. Graphite is a foreign substrate widely known for its high purity and high temperature resistance (> 1300C). The purposes of this work are to develop cell concepts, to characterize and furthermore to improve the performance of CSiTF solar cells on graphite substrates. Three new ...

  15. Properties of ITO-AZO bilayer thin films prepared by magnetron sputtering for applications in thin-film silicon solar cells

    In this paper we study the electro-optical behavior and the application of indium-tin oxide (ITO) and aluminum-doped zinc oxide (AZO) bilayer thin films for silicon solar cells. ITO-AZO bilayer thin films were deposited on glass substrates using radio-frequency magnetron sputtering. The experimental results show that a decrease in the electrical resistivity of the ITO-AZO bilayer thin films has been achieved without significant degradation of optical properties. In the best case the resistivity of the bilayer films reached a minimum of 5.075 x 10-4 ? cm when the thickness of the AZO buffer layer was 12 nm. The ITO-AZO bilayer films were applied as the front electrodes of amorphous silicon solar cells and the short-circuit current density of the solar cells was considerably increased. (orig.)

  16. Fabrication and performance of organic thin film solar cells using a painting method

    Ochiai, S.; Ishihara, H.; Mizutani, T.; Kojima, K.

    2010-05-01

    As organic thin film solar cells fabricated by the active layer of organic materials are economical, lightweight, and flexible, as well as generating no CO2, and being easy to fabricate, they have attracted significant attention as green energy sources from a past decade to date. Therefore, their power conversion efficiency (PCE) has been investigated and studied worldwide. In organic thinfilm solar cells, the effect of the performance depends not only on the adopted active material but also relates to the molecular orientation on the electrode. Using a mixed solution of Poly(3-hexylthiophene) and PCBM, both of which were dissolved in a solvent, the organic thin films were fabricated using the paint and spray methods, while the morphology of the thin film was evaluated by an AFM image, UV/vis spectra, and so forth. Based on these data, an organic thin-film solar cell using both solution methods for the active layer was fabricated, and the performance evaluated and examined. For organic thin film solar cells fabricated using a spin-coating method, the open-circuit voltage (Voc) is 0.41V, the short circuit current density (Jsc) is 2.07mA/cm2, and the fill factor is 0.34, while the efficiency η of PCE become 0.29%. In the spray method, the short circuit current (Isc) is 2.5 mA/cm2, the open circuit voltage (Voc) is 0.45 V, the fill factor (FF) is 0.28, and the power conversion factor (PCE) 0.35%. The area of organic solar cells fabricated by spin coating and spray methods is 1 cm2 respectively. The organic solar cells are not thermally treated, and hence have high respective power conversion efficiencies.

  17. Nanoscale investigation of potential distribution in operating Cu(In,Ga)Se2 thin-film solar cells

    Zhang, Zhenhao

    2012-01-01

    Thin-film solar cells based on CIGS absorber materials show the highest power conversion efficiency among all kinds of thin-film solar cells. The distribution of the electrostatic potential in and between the materials in the solar cell has obviously a major impact on the superior performance of the device. This thesis reported on imaging of the electrostatic potential on untreated cross sections of operating CIGS solar cells using Kelvin probe force microscopy.

  18. Polyol-mediated Synthesis of Chalcogenide Nanoparticles for Thin-film Solar Cells

    Dong, Hailong

    2014-01-01

    The aim of this work was polyol-mediated syntheses of chalcogenide nanoparticles for printable thin-film solar cells. In this thesis, chalcogenide nanoparticles, such as Cu2Se, In2Se3, CZTS, Se@CuSe and Te@Bi2Te3, have been successfully synthesized via a polyol-mediated method.

  19. Thin-Film Solar Cells Based on Amorphous and Microcrystalline Silicon

    Ballif, Christophe; Despeisse, Matthieu; Haug, Franz-Josef

    2015-10-01

    The following sections are included: * Introduction * Basic properties of amorphous and microcrystalline silicon alloys * Thin-film silicon solar cells * Fabrication of device-grade amorphous and microcrystalline silicon * Light management * Advanced device architecture and record devices * Industrialisation and large-area production technology * Acknowledgements * References

  20. Progress in Polycrystalline Thin-Film Cu(In,GaSe2 Solar Cells

    Udai P. Singh

    2010-01-01

    Full Text Available For some time, the chalcopyrite semiconductor CuInSe2 and its alloy with Ga and/or S [Cu(InGaSe2 or Cu(InGa(Se,S2], commonly referred as CIGS, have been leading thin-film material candidates for incorporation in high-efficiency photovoltaic devices. CuInSe2-based solar cells have shown long-term stability and the highest conversion efficiencies among all thin-film solar cells, reaching 20%. A variety of methods have been reported to prepare CIGS thin film. Efficiency of solar cells depends upon the various deposition methods as they control optoelectronic properties of the layers and interfaces. CIGS thin film grown on glass or flexible (metal foil, polyimide substrates require p-type absorber layers of optimum optoelectronic properties and n-type wideband gap partner layers to form the p-n junction. Transparent conducting oxide and specific metal layers are used for front and back contacts. Progress made in the field of CIGS solar cell in recent years has been reviewed.

  1. Disorder improves nanophotonic light trapping in thin-film solar cells

    We present a systematic experimental study on the impact of disorder in advanced nanophotonic light-trapping concepts of thin-film solar cells. Thin-film solar cells made of hydrogenated amorphous silicon were prepared on imprint-textured glass superstrates. For periodically textured superstrates of periods below 500?nm, the nanophotonic light-trapping effect is already superior to state-of-the-art randomly textured front contacts. The nanophotonic light-trapping effect can be associated to light coupling to leaky waveguide modes causing resonances in the external quantum efficiency of only a few nanometer widths for wavelengths longer than 500?nm. With increasing disorder of the nanotextured front contact, these resonances broaden and their relative altitude decreases. Moreover, overall the external quantum efficiency, i.e., the light-trapping effect, increases incrementally with increasing disorder. Thereby, our study is a systematic experimental proof that disorder is conceptually an advantage for nanophotonic light-trapping concepts employing grating couplers in thin-film solar cells. The result is relevant for the large field of research on nanophotonic light trapping in thin-film solar cells which currently investigates and prototypes a number of new concepts including disordered periodic and quasi periodic textures

  2. Low cost and high performance light trapping structure for thin-film solar cells

    Wang, DongLin; Su, Gang

    2015-01-01

    Nano-scaled dielectric and metallic structures are popular light tapping structures in thin-film solar cells. However, a large parasitic absorption in those structures is unavoidable. Most schemes based on such structures also involve the textured active layers that may bring undesirable degradation of the material quality. Here we propose a novel and cheap light trapping structure based on the prism structured SiO2 for thin-film solar cells, and a flat active layer is introduced purposefully. Such a light trapping structure is imposed by the geometrical shape optimization to gain the best optical benefit. By examining our scheme, it is disclosed that the conversion efficiency of the flat a-Si:H thin-film solar cell can be promoted to exceed the currently certified highest value. As the cost of SiO2-based light trapping structure is much cheaper and easier to fabricate than other materials, this proposal would have essential impact and wide applications in thin-film solar cells.

  3. Disorder improves nanophotonic light trapping in thin-film solar cells

    Paetzold, U. W., E-mail: u.paetzold@fz-juelich.de; Smeets, M.; Meier, M.; Bittkau, K.; Merdzhanova, T.; Smirnov, V.; Carius, R.; Rau, U. [IEK5—Photovoltaik, Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Michaelis, D.; Waechter, C. [Fraunhofer Institut für Angewandte Optik und Feinmechanik, Albert Einstein Str. 7, D-07745 Jena (Germany)

    2014-03-31

    We present a systematic experimental study on the impact of disorder in advanced nanophotonic light-trapping concepts of thin-film solar cells. Thin-film solar cells made of hydrogenated amorphous silicon were prepared on imprint-textured glass superstrates. For periodically textured superstrates of periods below 500 nm, the nanophotonic light-trapping effect is already superior to state-of-the-art randomly textured front contacts. The nanophotonic light-trapping effect can be associated to light coupling to leaky waveguide modes causing resonances in the external quantum efficiency of only a few nanometer widths for wavelengths longer than 500 nm. With increasing disorder of the nanotextured front contact, these resonances broaden and their relative altitude decreases. Moreover, overall the external quantum efficiency, i.e., the light-trapping effect, increases incrementally with increasing disorder. Thereby, our study is a systematic experimental proof that disorder is conceptually an advantage for nanophotonic light-trapping concepts employing grating couplers in thin-film solar cells. The result is relevant for the large field of research on nanophotonic light trapping in thin-film solar cells which currently investigates and prototypes a number of new concepts including disordered periodic and quasi periodic textures.

  4. Novel wide band gap materials for highly efficient thin film tandem solar cells

    Brian E. Hardin, Stephen T. Connor, Craig H. Peters

    2012-06-11

    Tandem solar cells (TSCs), which use two or more materials to absorb sunlight, have achieved power conversion efficiencies of >25% versus 11-20% for commercialized single junction solar cell modules. The key to widespread commercialization of TSCs is to develop the wide-band, top solar cell that is both cheap to fabricate and has a high open-circuit voltage (i.e. >1V). Previous work in TSCs has generally focused on using expensive processing techniques with slow growth rates resulting in costs that are two orders of magnitude too expensive to be used in conventional solar cell modules. The objective of the PLANT PV proposal was to investigate the feasibility of using Ag(In,Ga)Se2 (AIGS) as the wide-bandgap absorber in the top cell of a thin film tandem solar cell (TSC). Despite being studied by very few in the solar community, AIGS solar cells have achieved one of the highest open-circuit voltages within the chalcogenide material family with a Voc of 949mV when grown with an expensive processing technique (i.e. Molecular Beam Epitaxy). PLANT PV’s goal in Phase I of the DOE SBIR was to 1) develop the chemistry to grow AIGS thin films via solution processing techniques to reduce costs and 2) fabricate new device architectures with high open-circuit voltage to produce full tandem solar cells in Phase II. PLANT PV attempted to translate solution processing chemistries that were successful in producing >12% efficient Cu(In,Ga)Se2 solar cells by replacing copper compounds with silver. The main thrust of the research was to determine if it was possible to make high quality AIGS thin films using solution processing and to fully characterize the materials properties. PLANT PV developed several different types of silver compounds in an attempt to fabricate high quality thin films from solution. We found that silver compounds that were similar to the copper based system did not result in high quality thin films. PLANT PV was able to deposit AIGS thin films using a mixture of solution and physical vapor deposition processing, but these films lacked the p-type doping levels that are required to make decent solar cells. Over the course of the project PLANT PV was able to fabricate efficient CIGS solar cells (8.7%) but could not achieve equivalent performance using AIGS. During the nine-month grant PLANT PV set up a variety of thin film characterization tools (e.g. drive-level capacitance profiling) at the Molecular Foundry, a Department of Energy User Facility, that are now available to both industrial and academic researchers via the grant process. PLANT PV was also able to develop the back end processing of thin film solar cells at Lawrence Berkeley National Labs to achieve 8.7% efficient CIGS solar cells. This processing development will be applied to other types of thin film PV cells at the Lawrence Berkeley National Labs. While PLANT PV was able to study AIGS film growth and optoelectronic properties we concluded that AIGS produced using these methods would have a limited efficiency and would not be commercially feasible. PLANT PV did not apply for the Phase II of this grant.

  5. Indium sulfide thin films as window layer in chemically deposited solar cells

    Lugo-Loredo, S. [Universidad Autónoma de Nuevo León, UANL, Fac. de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria San Nicolás de Los Garza Nuevo León, C.P. 66451 (Mexico); Peña-Méndez, Y., E-mail: yolapm@gmail.com [Universidad Autónoma de Nuevo León, UANL, Fac. de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria San Nicolás de Los Garza Nuevo León, C.P. 66451 (Mexico); Calixto-Rodriguez, M. [Universidad Tecnológica Emiliano Zapata del Estado de Morelos, Av. Universidad Tecnológica No. 1, C.P. 62760 Emiliano Zapata, Morelos (Mexico); Messina-Fernández, S. [Universidad Autónoma de Nayarit, Ciudad de la Cultura “Amado Nervo” S/N, C.P. 63190 Tepic, Nayarit (Mexico); Alvarez-Gallegos, A. [Universidad Autónoma del Estado de Morelos, Centro de Investigación en Ingeniería y Ciencias Aplicadas, Av. Universidad 1001, C.P. 62209, Cuernavaca Morelos (Mexico); Vázquez-Dimas, A.; Hernández-García, T. [Universidad Autónoma de Nuevo León, UANL, Fac. de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria San Nicolás de Los Garza Nuevo León, C.P. 66451 (Mexico)

    2014-01-01

    Indium sulfide (In{sub 2}S{sub 3}) thin films have been synthesized by chemical bath deposition technique onto glass substrates using In(NO{sub 3}){sub 3} as indium precursor and thioacetamide as sulfur source. X-ray diffraction studies have shown that the crystalline state of the as-prepared and the annealed films is β-In{sub 2}S{sub 3}. Optical band gap values between 2.27 and 2.41 eV were obtained for these films. The In{sub 2}S{sub 3} thin films are photosensitive with an electrical conductivity value in the range of 10{sup −3}–10{sup −7} (Ω cm){sup −1}, depending on the film preparation conditions. We have demonstrated that the In{sub 2}S{sub 3} thin films obtained in this work are suitable candidates to be used as window layer in thin film solar cells. These films were integrated in SnO{sub 2}:F/In{sub 2}S{sub 3}/Sb{sub 2}S{sub 3}/PbS/C–Ag solar cell structures, which showed an open circuit voltage of 630 mV and a short circuit current density of 0.6 mA/cm{sup 2}. - Highlights: • In{sub 2}S{sub 3} thin films were deposited using the Chemical Bath Deposition technique. • A direct energy band gap between 2.41 to 2.27 eV was evaluated for the In{sub 2}S{sub 3} films. • We made chemically deposited solar cells using the In{sub 2}S{sub 3} thin films.

  6. Method and apparatus for fabricating a thin-film solar cell utilizing a hot wire chemical vapor deposition technique

    Wang, Qi; Iwaniczko, Eugene

    2006-10-17

    A thin-film solar cell is provided. The thin-film solar cell comprises an a-SiGe:H (1.6 eV) n-i-p solar cell having a deposition rate of at least ten (10) .ANG./second for the a-SiGe:H intrinsic layer by hot wire chemical vapor deposition. A method for fabricating a thin film solar cell is also provided. The method comprises depositing a n-i-p layer at a deposition rate of at least ten (10) .ANG./second for the a-SiGe:H intrinsic layer.

  7. Angular dependence of light trapping in nanophotonic thin-film solar cells.

    Smeets, Michael; Smirnov, Vladimir; Bittkau, Karsten; Meier, Matthias; Carius, Reinhard; Rau, Uwe; Paetzold, Ulrich W

    2015-11-30

    The angular dependence of light-trapping in nanophotonic thin-film solar cells is inherent due to the wavelength-scale dimensions of the periodic nanopatterns. In this paper, we experimentally investigate the dependence of light coupling to waveguide modes for light trapping in a-Si:H solar cells deposited on nanopatterned back contacts. First, we accurately determine the spectral positions of individual waveguide modes in thin-film solar cells in external quantum efficiency and absorptance. Second, we demonstrate the strong angular dependence of this spectral position for our solar cells. Third, a moderate level of disorder is introduced to the initially periodic nanopattern of the back contacts. As a result, the angular dependence is reduced. Last, we experimentally compare this dependence on the angle of incidence for randomly textured, 2D periodically nanopatterned and 2D disordered back contacts in external quantum efficiency and short-circuit current density. PMID:26698805

  8. Low resistivity molybdenum thin film towards the back contact of dye-sensitized solar cell

    Vuong Son; Tran Thi Ha; Luong T Thu Thuy; Nguyen Ngoc Ha; Nguyen Duc Chien; Mai Anh Tuan

    2015-12-01

    This paper reports the optimization of the molybdenum thin film electrode as the back contact of dye-sensitized solar cell (DSSC). The molybdenum thin film was grown on the glass substrate by direct current sputtering techniques of which the sputtering power was 150Wat 18 sccm flow rate of Ar. At such sputtering parameters, the Mo film can reach the lowest resistivity of 1.28E−6 cm at 400 nm thick. And the reflection of Mo membrane was 82%. This value is considered as a very good result for preparation of the back contact of DSSC.

  9. On the Scalar Scattering Theory for Thin-Film Solar Cells

    Jäger, K.

    2012-01-01

    Nano-textured interfaces between two media of different refractive indices scatter light. The angular distribution and the intensity of the scattered light are deter- mined by the geometry of the nano-textures and the difference of the refractive indices of the two media. Thin-film silicon solar cells (TFSSC), which convert sunlight directly into electricity, have nano-textured interfaces. These interfaces scatter the light incident on the solar cell. The scattering leads to a longer average ...

  10. Materials and Light Management for High-Efficiency Thin-Film Silicon Solar Cells :

    Tan, H

    2015-01-01

    Direct conversion of sunlight into electricity is one of the most promising approaches to provide sufficient renewable energy for humankind. Solar cells are such devices which can efficiently generate electricity from sunlight through the photovoltaic effect. Thin-film silicon solar cells, a type of photovoltaic (PV) devices which deploy the chemical-vapor-deposited hydrogenated amorphous silicon (a-Si:H) and nanocrystalline silicon (nc-Si:H) and their alloys as the absorber layers and doped ...

  11. Light-Management Strategies for Thin-Film Silicon Multijunction Solar Cells

    Niesen, Bjrn; Schttauf, Jan-Willem Alexander; Moulin, Etienne Antoine Julien; Hnni, Simon; Boccard, Mathieu; Feuser, Elmar; Niquille, Xavier; Stuckelberger, Michael; Blondiaux, Nicolas; Pugin, Raphal; Scolan, Emmanuel; Sculati-Meillaud, Fanny; Hessler-Wyser, Acha; Ballif, Christophe

    2014-01-01

    Light management is of crucial importance to reach high efficiencies with thin-film silicon multijunction solar cells. In this contribution, we present light-management strategies that we recently developed. This includes high quality absorber materials, low-refractive index intermediate reflectors, and highly transparent multiscale electrodes. Specifically, we show the fabrication of high-efficiency tandem devices with a certified stabilized efficiency of 12.6%, triple-junction solar cells w...

  12. Fully Solution-Processed Copper Chalcopyrite Thin Film Solar Cells: Materials Chemistry, Processing, and Device Physics

    Chung, Choong-Heui

    2012-01-01

    Chalcopyrite solar cells have attracted a lot of attention due to their highest power conversion efficiency among all thin film solar cells. However, significant cost reductions as well as large scale production are necessary to compete with conventional electrical power generation. The development of new deposition technologies for the absorber layer as well as the conducting window layer that are compatible with atmospheric deposition on a manufacturing-scale are urgently required to signif...

  13. Single-layer organicinorganic-hybrid thin-film encapsulation for organic solar cells

    We demonstrate an organicinorganic-hybrid thin-film encapsulation technique for organic solar cells. The single-layer encapsulation thin film is deposited from a gas mixture of hexamethyldisiloxane and oxygen by plasma-enhanced chemical vapour deposition at room temperature. The encapsulation film contains organic and inorganic compounds: the inorganic compounds serve as the permeation barriers, and the organic compounds reduce defect propagation. An optical transmission of ?90% in the visible light region and a water vapour transmission rate of 3.6 10?6 g m?2 day are obtained for a 1.5 m thick hybrid film. Efficiency decay is not observed in the inverted organic solar cell coated with this thin film after exposure to air for 3600 h; in contrast, the efficiency of the unencapsulated counterpart degrades rapidly and fails after exposure to air for 120 h. The obtained results show that this organicinorganic-hybrid thin film is promising for the encapsulation of organic solar cells. (paper)

  14. Depth selective laser scribing of thin-film silicon solar cells on foil

    Wipliez, L.A.; Loeffler, J.; De Keijzer, M.A.; Soppe, W.J.; Sebastien, T.A. [Energy Research Centre of The Netherlands, P.O. Box 1, 1755 ZG Petten (Netherlands); Schoonderbeek, A.; Haupt, O.; Stute, U. [Laser Zentrum Hannover e.V., Hollerithallee 8, D-30419 Hannover (Germany)

    2010-10-15

    Roll-to-roll production of thin-film photovoltaic (PV) solar cells and modules is expected to decrease substantially the manufacturing costs, and thus enable a breakthrough in the price of solar electricity per kWh. The roll-to-roll concept implies that the fabrication of these PV devices on flexible substrates is significantly different from the production of the glass based devices. This is especially valid for the monolithic series interconnection of thin-film silicon solar cells into modules, where the laser scribing step of thin-films on opaque foils requires depth selectivity. As adjusting the laser wavelength to the absorption profiles of the involved layers is not sufficient, we are investigating the ablation mechanisms leading to removal of the different layers of thin-film silicon solar cells. In this paper, first results of laser scribes into working solar cells are reported using 1064 nm nanosecond pulsed lasers. Despite the apparent depth selectivity reported earlier for this type of laser, a reduced diode quality and/or shunting of the solar cells is observed. This is probably due to recast at the wall of the laser scribe either by molten material from the back contact or by re-crystallized silicon. Consequently, a broader wavelength/pulse duration matrix has been experimented to understand better the ablation processes of the individual layers, aiming at a reduction of damage of the PV devices due to the laser process. Finally, laser scribes with reduced damage on working solar cells have been achieved with a near IR picosecond laser, leading to lower losses of the solar cell efficiency than with the 1064 nm nanosecond laser.

  15. Fabrication of organic-inorganic perovskite thin films for planar solar cells via pulsed laser deposition

    We report on fabrication of organic-inorganic perovskite thin films using a hybrid method consisting of pulsed laser deposition (PLD) of lead iodide and spin-coating of methylammonium iodide. Smooth and highly crystalline CH3NH3PbI3 thin films have been fabricated on silicon and glass coated substrates with fluorine doped tin oxide using this PLD-based hybrid method. Planar perovskite solar cells with an inverted structure have been successfully fabricated using the perovskite films. Because of its versatility, the PLD-based hybrid fabrication method not only provides an easy and precise control of the thickness of the perovskite thin films, but also offers a straightforward platform for studying the potential feasibility in using other metal halides and organic salts for formation of the organic-inorganic perovskite structure

  16. Fabrication of organic-inorganic perovskite thin films for planar solar cells via pulsed laser deposition

    Liang, Yangang; Yao, Yangyi; Zhang, Xiaohang; Hsu, Wei-Lun; Gong, Yunhui; Shin, Jongmoon; Wachsman, Eric D.; Dagenais, Mario; Takeuchi, Ichiro

    2016-01-01

    We report on fabrication of organic-inorganic perovskite thin films using a hybrid method consisting of pulsed laser deposition (PLD) of lead iodide and spin-coating of methylammonium iodide. Smooth and highly crystalline CH3NH3PbI3 thin films have been fabricated on silicon and glass coated substrates with fluorine doped tin oxide using this PLD-based hybrid method. Planar perovskite solar cells with an inverted structure have been successfully fabricated using the perovskite films. Because of its versatility, the PLD-based hybrid fabrication method not only provides an easy and precise control of the thickness of the perovskite thin films, but also offers a straightforward platform for studying the potential feasibility in using other metal halides and organic salts for formation of the organic-inorganic perovskite structure.

  17. Fabrication of organic-inorganic perovskite thin films for planar solar cells via pulsed laser deposition

    Yangang Liang

    2016-01-01

    Full Text Available We report on fabrication of organic-inorganic perovskite thin films using a hybrid method consisting of pulsed laser deposition (PLD of lead iodide and spin-coating of methylammonium iodide. Smooth and highly crystalline CH3NH3PbI3 thin films have been fabricated on silicon and glass coated substrates with fluorine doped tin oxide using this PLD-based hybrid method. Planar perovskite solar cells with an inverted structure have been successfully fabricated using the perovskite films. Because of its versatility, the PLD-based hybrid fabrication method not only provides an easy and precise control of the thickness of the perovskite thin films, but also offers a straightforward platform for studying the potential feasibility in using other metal halides and organic salts for formation of the organic-inorganic perovskite structure.

  18. Plasmonic light trapping in thin-film Si solar cells

    Plasmonic nanostructures have been recently investigated as a possible way to improve absorption of light in solar cells. The strong interaction of small metal nanostructures with light allows control over the propagation of light at the nanoscale and thus the design of ultrathin solar cells in which light is trapped in the active layer and efficiently absorbed. In this paper we review some of our recent work in the field of plasmonics for improved solar cells. We have investigated two possible ways of integrating metal nanoparticles in a solar cell. First, a layer of Ag nanoparticles that improves the standard antireflection coating used for crystalline and amorphous silicon solar cells has been designed and fabricated. Second, regular and random arrays of metal nanostructures have been designed to couple light in waveguide modes of thin semiconductor layers. Using a large-scale, relative inexpensive nano-imprint technique, we have designed a back-contact light trapping surface for a-Si:H solar cells which show enhanced efficiency over standard randomly textured cells. (review article)

  19. ANNEALING OF POLYCRYSTALLINE THIN FILM SILICON SOLAR CELLS IN WATER VAPOUR AT SUB-ATMOSPHERIC PRESSURES

    Peter Pikna

    2014-10-01

    Full Text Available Thin film polycrystalline silicon (poly-Si solar cells were annealed in water vapour at pressures below atmospheric pressure. PN junction of the sample was contacted by measuring probes directly in the pressure chamber filled with steam during passivation. Suns-VOC method and a Lock-in detector were used to monitor an effect of water vapour to VOC of the solar cell during whole passivation process (in-situ. Tested temperature of the sample (55°C – 110°C was constant during the procedure. Open-circuit voltage of a solar cell at these temperatures is lower than at room temperature. Nevertheless, voltage response of the solar cell to the light flash used during Suns-VOC measurements was good observable. Temperature dependences for multicrystalline wafer-based and polycrystalline thin film solar cells were measured and compared. While no significant improvement of thin film poly-Si solar cell parameters by annealing in water vapour at under-atmospheric pressures was observed up to now, in-situ observation proved required sensitivity to changing VOC at elevated temperatures during the process.

  20. Thin film solar cell inflatable ultraviolet rigidizable deployment hinge

    Simburger, Edward J. (Inventor); Matsumoto, James H. (Inventor); Giants, Thomas W. (Inventor); Garcia, III, Alec (Inventor); Perry, Alan R. (Inventor); Rawal, Suraj (Inventor); Marshall, Craig H. (Inventor); Lin, John K. H. (Inventor); Day, Jonathan Robert (Inventor); Kerslake, Thomas W. (Inventor)

    2010-01-01

    A flexible inflatable hinge includes curable resin for rigidly positioning panels of solar cells about the hinge in which wrap around contacts and flex circuits are disposed for routing power from the solar cells to the power bus further used for grounding the hinge. An indium tin oxide and magnesium fluoride coating is used to prevent static discharge while being transparent to ultraviolet light that cures the embedded resin after deployment for rigidizing the inflatable hinge.

  1. Interfacial Properties of CZTS Thin Film Solar Cell

    N. Muhunthan; Om Pal Singh; Thakur, M.K.; P Karthikeyan; Dinesh Singh; Saravanan, M.; Singh, V. N.

    2014-01-01

    Cu-deficient CZTS (copper zinc tin sulfide) thin films were grown on soda lime as well as molybdenum coated soda lime glass by reactive cosputtering. Polycrystalline CZTS film with kesterite structure was produced by annealing it at 500C in Ar atmosphere. These films were characterized for compositional, structural, surface morphological, optical, and transport properties using energy dispersive X-ray analysis, glancing incidence X-ray diffraction, Raman spectroscopy, scanning electron micro...

  2. Laser process for extended silicon thin film solar cells

    We present a large area thin film base substrate for the epitaxy of crystalline silicon. The concept of epitaxial growth of silicon on large area thin film substrates overcomes the area restrictions of an ingot based monocrystalline silicon process. Further it opens the possibility for a roll to roll process for crystalline silicon production. This concept suggests a technical pathway to overcome the limitations of silicon ingot production in terms of costs, throughput and completely prevents any sawing losses. The core idea behind these thin film substrates is a laser welding process of individual, thin silicon wafers. In this manuscript we investigate the properties of laser welded monocrystalline silicon foils (100) by micro-Raman mapping and spectroscopy. It is shown that the laser beam changes the crystalline structure of float zone grown silicon along the welding seam. This is illustrated by Raman mapping which visualizes compressive stress as well as tensile stress in a range of - 147.5 to 32.5 MPa along the welding area.

  3. Thin film cadmium telluride, zinc telluride, and mercury zinc telluride solar cells

    Chu, T.L. (University of South Florida, Tampa, FL (United States))

    1992-04-01

    This report describes research to demonstrate (1) thin film cadmium telluride solar cells with a quantum efficiency of 75% or higher at 0. 44 {mu}m and a photovoltaic efficiency of 11.5% or greater, and (2) thin film zinc telluride and mercury zinc telluride solar cells with a transparency to sub-band-gap radiation of 65% and a photovoltaic conversion efficiency of 5% and 8%, respectively. Work was directed at (1) depositing transparent conducting semiconductor films by solution growth and metal-organic chemical vapor deposition (MOCVD) technique, (2) depositing CdTe films by close-spaced sublimation (CSS) and MOCVD techniques, (3) preparing and evaluating thin film CdTe solar cells, and (4) preparing and characterizing thin film ZnTe, CD{sub 1-x}Zn{sub 1-x}Te, and Hg{sub 1-x}Zn{sub x}Te solar cells. The deposition of CdS films from aqueous solutions was investigated in detail, and their crystallographic, optical, and electrical properties were characterized. CdTe films were deposited from DMCd and DIPTe at 400{degrees}C using TEGa and AsH{sub 3} as dopants. CdTe films deposited by CSS had significantly better microstructures than those deposited by MOCVD. Deep energy states in CdTe films deposited by CSS and MOCVD were investigated. Thin films of ZnTe, Cd{sub 1- x}Zn{sub x}Te, and Hg{sub 1-x}Zn{sub x}Te were deposited by MOCVD, and their crystallographic, optical, and electrical properties were characterized. 67 refs.

  4. Recent advances in the transparent conducting ZnO for thin-film Si solar cells

    Moon, Taeho; Shin, Gwang Su; Park, Byungwoo

    2015-11-01

    The key challenge for solar-cell development lies in the improvement of power-conversion efficiency and the reduction of fabrication cost. For thin-film Si solar cells, researches have been especially focused on the light trapping for the breakthrough in the saturated efficiencies. The ZnO-based transparent conducting oxides (TCOs) have therefore received strong attention because of their excellent light-scattering capability by the texture-etched surface and cost effectiveness through in-house fabrication. Here, we have highlighted our recent studies on the transparent conducting ZnO for thin-film Si solar cells. From the electrical properties and their degradation mechanisms, bilayer deposition and organic-acid texturing approaches for enhancing the light trapping, and finally the relation between textured ZnO and electrical cell performances are sequentially introduced in this review article. [Figure not available: see fulltext.

  5. Photon management in thin-film solar cells; Photon-Management in Duennschicht-Solarzellen

    Fahr, Stephan

    2011-11-22

    In this thesis procedures were presented, which modify the propagation of the incident light in such a way that by this the efficiency of thin-film solar cells is increased. The strength of the presented numerical studies lies thereby in the rigorous solution of Maxwell's equations. Fundamental statements concerning the lay-out of an ideal texture could be made, which for present thin-film solar cells over the whole relevant spectral range both suppresses reflection losses and leads to an elongation of the effective path. Object of the thesis was also the design of a spectral- and angular-selective filter, which confines the acceptance angle of a solar cell with the aim of an improved absorption in the long-wave spectral region. Furthermore also tandem cells on the base of amorphous and microcrystalline silicon were studied.

  6. High-efficiency thin-film solar cells for the conversion of concentrated radiation

    Andreev, V. M.; Burba, T. S.; Dorgan, V. V.; Trofim, V. G.; Chumak, V. A.

    1987-09-01

    The objective of the study was to investigate the possibility of increasing the efficiency of thin-film solar cells with coplanar back contacts for the conversion of concentrated solar radiation. It is shown that, in the thin-film solar cells described here, the cell shading factor can be reduced to a minimum since it does not depend on the p-contact area but is determined solely by the area of etched grooves in a thin (7 microns) layer of GaAs. The cells used in the study have a shading factor of 2.5 percent, and a further reduction by an order of magnitude is shown to be possible.

  7. High-efficiency thin-film solar cells for the conversion of concentrated radiation

    Andreev, V.M.; Burba, T.S.; Dorgan, V.V.; Trofim, V.G.; Chumak, V.A.

    1987-09-01

    The objective of the study was to investigate the possibility of increasing the efficiency of thin-film solar cells with coplanar back contacts for the conversion of concentrated solar radiation. It is shown that, in the thin-film solar cells described here, the cell shading factor can be reduced to a minimum since it does not depend on the p-contact area but is determined solely by the area of etched grooves in a thin (7 microns) layer of GaAs. The cells used in the study have a shading factor of 2.5 percent, and a further reduction by an order of magnitude is shown to be possible. 6 references.

  8. Advanced electrical simulation of thin film solar cells

    Burgelman, Marc, E-mail: Marc.Burgelman@elis.ugent.be; Decock, Koen; Khelifi, Samira; Abass, Aimi

    2013-05-01

    Advanced electrical simulation of copper indium gallium diselenide solar cells is illustrated by setting up a demonstration case in SCAPS (Solar Cell Capacitance Simulator), the solar cell simulation programme of the University of Gent. The model includes band gap grading, multivalent defects and metastable transitions between defects. This simplified demonstration model clearly and quantitatively illustrates some topics that were extensively discussed in recent literature: metastable defects exist in either an acceptor or in a donor configuration; the occupation of these configurations is set during initial conditions at higher temperature, and then frozen in during cell operation at lower temperature. These occupations can strongly influence the effective doping profile in the absorber, and hence possible energy barriers in the structure. The dependence of such barriers on the initial conditions and on the operating voltage can cause a considerable dependence of the currentvoltage characteristics on the initial conditions, especially of the fill factor. At the same time, the demonstration model illustrates some of the recent extensions of SCAPS. - Highlights: ? SCAPS, the Solar Cell Capacitance Simulator of UGent is freely available. ? SCAPS is keeping up with the sophistication of state-of-the-art solar cells. ? It can now handle: multivalent and metastable defects; grading of all properties. ? It is shown how metastable defects can lead to metastable cell characteristics. ? A relation conduction band barrier-fill factor is numerically established.

  9. Advanced electrical simulation of thin film solar cells

    Advanced electrical simulation of copper indium gallium diselenide solar cells is illustrated by setting up a demonstration case in SCAPS (Solar Cell Capacitance Simulator), the solar cell simulation programme of the University of Gent. The model includes band gap grading, multivalent defects and metastable transitions between defects. This simplified demonstration model clearly and quantitatively illustrates some topics that were extensively discussed in recent literature: metastable defects exist in either an acceptor or in a donor configuration; the occupation of these configurations is set during initial conditions at higher temperature, and then frozen in during cell operation at lower temperature. These occupations can strongly influence the effective doping profile in the absorber, and hence possible energy barriers in the structure. The dependence of such barriers on the initial conditions and on the operating voltage can cause a considerable dependence of the current–voltage characteristics on the initial conditions, especially of the fill factor. At the same time, the demonstration model illustrates some of the recent extensions of SCAPS. - Highlights: ► SCAPS, the Solar Cell Capacitance Simulator of UGent is freely available. ► SCAPS is keeping up with the sophistication of state-of-the-art solar cells. ► It can now handle: multivalent and metastable defects; grading of all properties. ► It is shown how metastable defects can lead to metastable cell characteristics. ► A relation conduction band barrier-fill factor is numerically established

  10. Thin film solar cell configuration and fabrication method

    Menezes, Shalini

    2009-07-14

    A new photovoltaic device configuration based on an n-copper indium selenide absorber and a p-type window is disclosed. A fabrication method to produce this device on flexible or rigid substrates is described that reduces the number of cell components, avoids hazardous materials, simplifies the process steps and hence the costs for high volume solar cell manufacturing.

  11. Advances in Thin-Film Si Solar Cells by Means of SiOx Alloys

    Mercaldo, Lucia V.; Iurie Usatii; Paola Delli Veneri

    2016-01-01

    The conversion efficiency of thin-film silicon solar cells needs to be improved to be competitive with respect to other technologies. For a more efficient use of light across the solar spectrum, multi-junction architectures are being considered. Light-management considerations are also crucial in order to maximize light absorption in the active regions with a minimum of parasitic optical losses in the supportive layers. Intrinsic and doped silicon oxide alloys can be advantageously applied wi...

  12. Thin-Film Solar Cell Fabricated on a Flexible Metallic Substrate

    Tuttle, J. R.; Noufi, R.; Hasoon, F. S.

    2006-05-30

    A thin-film solar cell (10) is provided. The thin-film solar cell (10) comprises a flexible metallic substrate (12) having a first surface and a second surface. A back metal contact layer (16) is deposited on the first surface of the flexible metallic substrate (12). A semiconductor absorber layer (14) is deposited on the back metal contact. A photoactive film deposited on the semiconductor absorber layer (14) forms a heterojunction structure and a grid contact (24) deposited on the heterjunction structure. The flexible metal substrate (12) can be constructed of either aluminium or stainless steel. Furthermore, a method of constructing a solar cell is provided. The method comprises providing an aluminum substrate (12), depositing a semiconductor absorber layer (14) on the aluminum substrate (12), and insulating the aluminum substrate (12) from the semiconductor absorber layer (14) to inhibit reaction between the aluminum substrate (12) and the semiconductor absorber layer (14).

  13. Transfer printing methods for flexible thin film solar cells: basic concepts and working principles.

    Lee, Chi Hwan; Kim, Dong Rip; Zheng, Xiaolin

    2014-09-23

    Fabricating thin film solar cells (TFSCs) on flexible substrates will not only broaden the applications of solar cells, but also potentially reduce the installation cost. However, a critical challenge for fabricating flexible TFSCs on flexible substrates is the incompatibility issues between the thermal, mechanical, and chemical properties of these substrates and the fabrication conditions. Transfer printing methods, which use conventional substrates for the fabrication and then deliver the TFSCs onto flexible substrates, play a key role to overcome these challenges. In this review, we discuss the basic concepts and working principles of four major transfer printing methods associated with (1) transfer by sacrificial layers, (2) transfer by porous Si layer, (3) transfer by controlled crack, and (4) transfer by water-assisted thin film delamination. We also discuss the challenges and opportunities for implementing these methods for practical solar cell manufacture. PMID:25184987

  14. Plasmonic Light Trapping in Thin-Film Solar Cells: Impact of Modeling on Performance Prediction

    Alberto Micco

    2015-06-01

    Full Text Available We present a comparative study on numerical models used to predict the absorption enhancement in thin-film solar cells due to the presence of structured back-reflectors exciting, at specific wavelengths, hybrid plasmonic-photonic resonances. To evaluate the effectiveness of the analyzed models, they have been applied in a case study: starting from a U-shaped textured glass thin-film, µc-Si:H solar cells have been successfully fabricated. The fabricated cells, with different intrinsic layer thicknesses, have been morphologically, optically and electrically characterized. The experimental results have been successively compared with the numerical predictions. We have found that, in contrast to basic models based on the underlying schematics of the cell, numerical models taking into account the real morphology of the fabricated device, are able to effectively predict the cells performances in terms of both optical absorption and short-circuit current values.

  15. Advanced characterization techniques for thin film solar cells

    Rau, Uwe; Kirchartz, Thomas

    2011-01-01

    Written by scientists from leading institutes in Germany, USA and Spain who use these techniques as the core of their scientific work and who have a precise idea of what is relevant for photovoltaic devices, this text contains concise and comprehensive lecture-like chapters on specific research methods.They focus on emerging, specialized techniques that are new to the field of photovoltaics yet have a proven relevance. However, since new methods need to be judged according to their implications for photovoltaic devices, a clear introductory chapter describes the basic physics of thin-film

  16. Processing and modeling issues for thin-film solar cell devices. Final report

    Birkmire, R.W.; Phillips, J.E. [Univ. of Delaware, Newark, DE (United States). Institute of Energy Conversion

    1997-11-01

    During the third phase of the subcontract, IEC researchers have continued to provide the thin film PV community with greater depth of understanding and insight into a wide variety of issues including: the deposition and characterization of CuIn{sub 1-x}Ga{sub x}Se{sub 2}, a-Si, CdTe, CdS, and TCO thin films; the relationships between film and device properties; and the processing and analysis of thin film PV devices. This has been achieved through the systematic investigation of all aspects of film and device production and through the analysis and quantification of the reaction chemistries involved in thin film deposition. This methodology has led to controlled fabrications of 15% efficient CuIn{sub 1-x}Ga{sub x}Se{sub 2} solar cells over a wide range of Ga compositions, improved process control of the fabrication of 10% efficient a-Si solar cells, and reliable and generally applicable procedures for both contacting and doping films. Additional accomplishments are listed below.

  17. Thermal Characteristics of Multilayer Insulation Materials for Flexible Thin-Film Solar Cell Array of Stratospheric Airship

    Kangwen Sun; Qinzhen Yang; Yang Yang; Shun Wang; Jianming Xu; Qiang Liu; Yong Xie; Peng Lou

    2014-01-01

    Flexible thin-film solar cell is an efficient energy system on the surface of stratospheric airship for utilizing the solar energy. In order to ensure the normal operation of airship platform, the thermal control problem between the flexible thin-film solar cell and the airship envelope should be properly resolved. In this paper, a multilayer insulation material (MLI) is developed first, and low temperature environment test is carried out to verify the insulation effect of MLI. Then, a therma...

  18. Development of a thin film solar cell interconnect for the PowerSphere concept

    Progressive development of microsatellite technologies has resulted in increased demand for lightweight electrical power subsystems including solar arrays. The use of thin film photovoltaics has been recognized as a key solution to meet the power needs. The lightweight cells can generate sufficient power and still meet critical mass requirements. Commercially available solar cells produced on lightweight substrates are being studied as an option to fulfill the power needs. The commercially available solar cells are relatively inexpensive and have a high payoff potential. Commercially available thin film solar cells are primarily being produced for terrestrial applications. The need to convert the solar cell from a terrestrial to a space compatible application is the primary challenge. Solar cell contacts, grids and interconnects need to be designed to be atomic oxygen resistant and withstand rapid thermal cycling environments. A mechanically robust solar cell interconnect is also required in order to withstand handling during fabrication and survive during launch. The need to produce the solar cell interconnects has been identified as a primary goal of the PowerSphere program and is the topic of this paper. Details of the trade study leading to the final design involving the solar cell wrap around contact, flex blanket, welding process, and frame will be presented at the conference

  19. Development of a Thin Film Solar Cell Interconnect for the Powersphere Concept

    Simburger, Edward J.; Matsumoto, James H.; Giants, Thomas W.; Garcia, Alexander, III; Liu, Simon; Rawal, Suraj P.; Perry, Alan R.; Marshall, Craig H.; Lin, John K.; Scarborough, Stephen

    2003-01-01

    Progressive development of microsatellite technologies has resulted in increased demand for lightweight electrical power subsystems including solar arrays. The use of thin film photovoltaics has been recognized as a key solution to meet the power needs. The lightweight cells can generate sufficient power and still meet critical mass requirements. Commercially available solar cells produced on lightweight substrates are being studied as an option to fulfill the power needs. The commercially available solar cells are relatively inexpensive and have a high payoff potential. Commercially available thin film solar cells are primarily being produced for terrestrial applications. The need to convert the solar cell from a terrestrial to a space compatible application is the primary challenge. Solar cell contacts, grids and interconnects need to be designed to be atomic oxygen resistant and withstand rapid thermal cycling environments. A mechanically robust solar cell interconnect is also required in order to withstand handling during fabrication and survive during launch. The need to produce the solar cell interconnects has been identified as a primary goal of the Powersphere program and is the topic of this paper. Details of the trade study leading to the final design involving the solar cell wrap around contact, flex blanket, welding process, and frame will be presented at the conference.

  20. Numerical modeling of SiH4 discharge for Si thin film deposition for thin film transistor and solar cells

    Amorphous and microcrystalline silicon thin films are used in solar cells as a multi-junction photovoltaic device. Plasma enhanced chemical vapor deposition is used and high deposition rate of a few nm/s is required while keeping film quality. SiH4 is used as a precursor diluted with H2. Electron impact processes give complex interdependent plasma chemical reactions. Many researchers suggest keeping high H/SiHx ratio is important. Numerical modeling of this process for capacitively coupled plasma and inductively coupled plasma is done to investigate which process parameters are playing key roles in determining it. A full set of 67 volume reactions and reduced set are used. Under most of conditions, CCP shows 100 times higher H/SiH3 ratio over ICP case due to its spatially localized two electron temperature distribution. Multi hollow cathode type CCP is also modeled as a 2 x 2 hole array. For Ar, the discharge is well localized at the neck of the hole at a few Torr of gas pressure. H2 and SiH4 + H2 needed higher gas pressure and power density to get a multi hole localized density profile. H/SiH3 was calculated to be about 1/10.

  1. Characterization of Thin Films for Polymer Solar Cells

    Tromholt, Thomas

    multi facetted process where oxygen and water diffusion from the atmosphere, morphology evolution, and photo-bleaching of the polymer are some of the dominant processes. Encapsulation by foils consisting of multi-layer polymer stacks is a conventional way to reduce the diffusion into the solar cell, by...... condition to conjugated polymers, has until this PhD work not been applied as an acceleration condition to polymer degradation. Light can be concentrated up to thousand of solar intensities by optical components, which has the potential to significantly accelerate polymer degradation. Concentration of light...

  2. Porous copper zinc tin sulfide thin film as photocathode for double junction photoelectrochemical solar cells.

    Dai, Pengcheng; Zhang, Guan; Chen, Yuncheng; Jiang, Hechun; Feng, Zhenyu; Lin, Zhaojun; Zhan, Jinhua

    2012-03-21

    Porous copper zinc tin sulfide (CZTS) thin film was prepared via a solvothermal approach. Compared with conventional dye-sensitized solar cells (DSSCs), double junction photoelectrochemical cells using dye-sensitized n-type TiO(2) (DS-TiO(2)) as the photoanode and porous p-type CZTS film as the photocathode shows an increased short circuit current, external quantum efficiency and power conversion efficiency. PMID:22322239

  3. Copper and Transparent-Conductor Reflectarray Elements on Thin-Film Solar Cell Panels

    Dreyer, Philippe; Morales-Masis, Monica; Nicolay, Sylvain; Ballif, Christophe; Perruisseau-Carrier, Julien

    2013-01-01

    This work addresses the integration of reflectarray antennas (RA) on thin film Solar Cell (SC) panels, as a mean to save real estate, weight, or cost in platforms such as satellites or transportable autonomous antenna systems. Our goal is to design a good RA unit cell in terms of phase response and bandwidth, while simultaneously achieving high optical transparency and low microwave loss, to preserve good SC and RA energy efficiencies, respectively. Since there is a trade-off between the opti...

  4. Comparison of silicon oxide and silicon carbide absorber materials in silicon thin-film solar cells

    Walder Cordula; Kellermann Martin; Wendler Elke; Rensberg Jura; von Maydell Karsten; Agert Carsten

    2015-01-01

    Since solar energy conversion by photovoltaics is most efficient for photon energies at the bandgap of the absorbing material the idea of combining absorber layers with different bandgaps in a multijunction cell has become popular. In silicon thin-film photovoltaics a multijunction stack with more than two subcells requires a high bandgap amorphous silicon alloy top cell absorber to achieve an optimal bandgap combination. We address the question whether amorphous silicon carbide (a-SiC:H) or ...

  5. Silicon -Light: a European project aiming at high efficiency thin film silicon solar cells on foil

    Soppe W.; Krc J.; Leitner K.; Haug F.-J.; Duchamp M.; Sanchez Plaza G.; Wang Q.-K.

    2014-01-01

    In the European project Silicon-Light we developed concepts and technologies to increase conversion efficiencies of thin film silicon solar cells on foil. Main focus was put on improved light management, using NIL for creating light scattering textures, improved TCOs using sputtering, and improved silicon absorber material made by PECVD. On foil we achieved initial cell efficiencies of 11% and on rigid substrates stable efficiencies of ...

  6. Ion beam treatment of functional layers in thin-film silicon solar cells

    Zhang, Wendi

    2013-01-01

    In silicon thin-film solar cells, transparent conductive layers have to fulfill the following requirements: high conductivity as effective contact, high transparency to transmit the light into the cell, and a textured surface which provides light scattering. Magnetron sputtered and wet-chemically textured aluminum doped zinc oxide (ZnO:Al) films are widely used as the transparent conductor. The technological goal of this dissertation is to develop an alternative to the wet etching process for...

  7. Thin Film CIGS Solar Cells, Photovoltaic Modules, and the Problems of Modeling

    Antonino Parisi; Luciano Curcio; Vincenzo Rocca; Salvatore Stivala; Cino, Alfonso C.; Busacca, Alessandro C.; Giovanni Cipriani; Diego La Cascia; Vincenzo Di Dio; Rosario Miceli; Giuseppe Ricco Galluzzo

    2013-01-01

    Starting from the results regarding a nonvacuum technique to fabricate CIGS thin films for solar cells by means of single-step electrodeposition, we focus on the methodological problems of modeling at cell structure and photovoltaic module levels. As a matter of fact, electrodeposition is known as a practical alternative to costly vacuum-based technologies for semiconductor processing in the photovoltaic device sector, but it can lead to quite different structural and electrical properties. F...

  8. Thin-Film Solar Cells on Metal Foil Substrates for Space Power

    Raffaelle, Ryne P.; Hepp, Aloysius F.; Hoffman, David J.; Dhere, N.; Tuttle, J. R.; Jin, Michael H.

    2004-01-01

    Photovoltaic arrays have played a key role in power generation in space. The current technology will continue to evolve but is limited in the important mass specific power metric (MSP or power/weight ratio) because it is based on bulk crystal technology. The objective of this research is to continue development of an innovative photovoltaic technology for satellite power sources that could provide up to an order of magnitude saving in both weight and cost, and is inherently radiation-tolerant through use of thin film technology and thin foil substrates such as 5-mil thick stainless steel foil or 1-mil thick Ti. Current single crystal technology for space power can cost more than $300 per watt at the array level and weigh more than 1 kg/sq m equivalent to specific power of approx. 65 W/kg. Thin film material such as CuIn(1-x),Ga(x)S2, (CIGS2), CuIn(1-x), G(x)Se(2-y),S(y), (CIGSS) or amorphous hydrogenated silicon (a-Si:H) may be able to reduce both the cost and mass per unit area by an order of magnitude. Manufacturing costs for solar arrays are an important consideration for total spacecraft budget. For a medium sized 5kW satellite, for example, the array manufacturing cost alone may exceed $2 million. Moving to thin film technology could reduce this expense to less than $500 K. Previous work at FSEC demonstrated the potential of achieving higher efficiencies from CIGSS thin film solar cells on 5-mil thick stainless steel foil as well as initial stages of facility augmentation for depositing thin film solar cells on larger (6"x 4") substrates. This paper presents further progress in processing on metal foil substrates. Also, previous work at DayStar demonstrated the feasibility of flexible-thin-film copper-indium-gallium-diselenide (CIGS) solar cells with a power-to-weight ratio in excess of 1000 W/kg. We will comment on progress on the critical issue of scale-up of the solar cell absorber deposition process. Several important technical issues need to be resolved to realize the benefits of lightweight technologies for solar arrays, such as: monolithic interconnects, lightweight array structures, and new ultra-light support and deployment mechanisms. Once the technology has gained spaceflight certification it should find rapid acceptance in specific satellite markets.

  9. Soft X-rays shedding light on thin-film solar cell surfaces and interfaces

    Bär, M., E-mail: marcus.baer@helmholtz-berlin.de [Solar Energy Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), D-14109 Berlin (Germany); Institut für Physik und Chemie, Brandenburgische Technische Universität Cottbus, D-03046 Cottbus (Germany); Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, NV 89154 (United States); Pookpanratana, S. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, NV 89154 (United States); Weinhardt, L. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, NV 89154 (United States); Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen (Germany); ANKA Synchrotron Radiation Facility, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen (Germany); Wilks, R.G.; Schubert, B.A.; Marsen, B.; Unold, T. [Solar Energy Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), D-14109 Berlin (Germany); Blum, M.; Krause, S. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, NV 89154 (United States); Zhang, Y. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, NV 89154 (United States); Department of Physics, Xiamen University, Xiamen, Fujian 361005 (China); Ranasinghe, A. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, NV 89154 (United States); Ramanathan, K.; Repins, I.; Contreras, M.A. [National Renewable Energy Laboratory (NREL), Golden, CO 80401 (United States); Nishiwaki, S. [Institute for Energy Conversion (IEC), University of Delaware, Newark, DE 19716 (United States); and others

    2013-10-15

    Highlights: ► S/Se gradient-driven chemical interaction at the CdS/CIG(S)Se interface. ► Depth-dependent band gap in chalcopyrites. ► Band alignment at the CdS/Cu{sub 2}ZnSnS{sub 4} solar cell heterojunction. ► Post-deposition treatment induces intermixing in the CdTe/CdS solar cell structure. -- Abstract: Thin-film solar cells based on compound semiconductors consist of a multilayer structure with various interfaces and contain a multitude of elements and impurities, etc. A rapid progress of these photovoltaic technologies can only be achieved by an insight-driven optimization/development. Hence it is crucial to characterize and understand the relationship between the chemical and electronic properties of these components. This paper reviews some examples of our recent work characterizing compound semiconductor thin films using laboratory- and synchrotron-based electron and soft X-ray spectroscopic characterization methods. It is demonstrated how these different analytical techniques are extraordinarily powerful to reveal the material characteristics from many different perspectives, ultimately resulting in a comprehensive picture of the related electronic and chemical properties. As examples, the paper will discuss the electronic surface structure of chalcopyrite thin-film solar cell absorbers, the chemical structure of the CdS/chalcopyrite interface, present the band alignment at the CdS/kesterite interface, and report on how post-deposition treatments cause chemical interaction/interdiffusion processes in CdTe/CdS thin-film solar cell structures.

  10. Polycrystalline Silicon Thin-Film Solar Cells on AIT-Textured Glass Superstrates

    Armin G. Aberle

    2007-12-01

    Full Text Available A new glass texturing method (AIT—aluminium-induced texturisation has recently been developed by our group. In the present work, the potential of this method is explored by fabricating PLASMA poly-Si thin-film solar cells on glass superstrates that were textured with the AIT method. Using an interdigitated metallisation scheme with a full-area Al rear contact, PLASMA cells with an efficiency of up to 7% are realised. This promising result shows that the AIT glass texturing method is fully compatible with the fabrication of poly-Si thin-film solar cells on glass using solid phase crystallisation (SPC of PECVD-deposited amorphous silicon precursor diodes. As such, there are now two distinctly different glass texturing methods—the AIT method and CSG Solar's glass bead method—that are known to be capable of producing efficient SPC poly-Si thin-film solar cells on glass.

  11. Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

    Wang, Lan; Lin, Xianzhong; Ennaoui, Ahmed; Wolf, Christian; Lux-Steiner, Martha Ch.; Klenk, Reiner

    2016-02-01

    We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating and inkjet printing. Active area efficiencies of 12.8% and 12.2% have been achieved for In2S3-buffered solar cells respectively, matching the performance of CdS-buffered cells prepared with the same batch of absorbers.

  12. Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

    Wang Lan

    2016-01-01

    Full Text Available We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating and inkjet printing. Active area efficiencies of 12.8% and 12.2% have been achieved for In2S3-buffered solar cells respectively, matching the performance of CdS-buffered cells prepared with the same batch of absorbers.

  13. Current Approach in Surface Plasmons for Thin Film and Wire Array Solar Cell Applications

    Keya Zhou

    2015-07-01

    Full Text Available Surface plasmons, which exist along the interface of a metal and a dielectric, have been proposed as an efficient alternative method for light trapping in solar cells during the past ten years. With unique properties such as superior light scattering, optical trapping, guide mode coupling, near field concentration, and hot-electron generation, metallic nanoparticles or nanostructures can be tailored to a certain geometric design to enhance solar cell conversion efficiency and to reduce the material costs. In this article, we review current approaches on different kinds of solar cells, such as crystalline silicon (c-Si and amorphous silicon (a-Si thin film solar cells, organic solar cells, nanowire array solar cells, and single nanowire solar cells.

  14. Cu(In1-xGax)Se2 based thin film solar cells

    Kodigala, Subba Ramaiah

    2011-01-01

    This book provides valuable contents about the fabrication and characterization of chalcopyrite Cu(In1-xGax)Se2 based thin film solar cells and modules. The growth of chalcopyrite Cu(In1-xGax)(S1-ySey)2 absorbers, buffers, window layers, antireflection coatings, and finally metallic grids, which are the sole components of solar cells, is clearly illustrated. The absorber, which contains multiple elements, segregates secondary phases if the growth conditions are not well optimized i.e., the main drawback in the fabrication of solar cells. More importantly the solutions for the growth of thin f

  15. Thin-film solar cells on perlite glass-ceramic substrates

    Petrosyan, Stepan G.; Babayan, Virab H.; Musayelyan, Ashot S.; Harutyunyan, Levon A.; Zalesski, Valery B.; Kravchenko, Vladimir M.; Leonova, Tatyana R.; Polikanin, Alexander M.; Khodin, Alexander A.

    2013-06-01

    For the first time, thin-film CIGS solar cells have been fabricated by co-evaporation on specially developed non-conducting perlite (an aluminum potassium sodium silicate natural mineral of volcanic origin) glass-ceramic substrates to develop a fully integrated photovoltaic and building element. Such glass-ceramic material can meet the physical requirements to solar cells substrates as well as the cost goals. The preliminary data presented show that CIGS solar cells deposited on ceramic substrates can exhibit efficiency higher than 10%.

  16. Computational and experimental study of a multi-layer absorptivity enhanced thin film silicon solar cell

    Hajimirza, Shima; Howell, John R.

    2014-08-01

    We report on the computational design, fabrication and validation of a multi-layer silicon based thin film solar cell. The cell structure consists of a thin absorber layer of amorphous silicon deposited on a back-reflector aluminum layer and coated on top with ITO transparent conductive oxide. The structure is mounted on a glass substrate. We first use constrained optimization techniques along with numerical solvers of the electromagnetic equations (i.e. FDTD) to tune the geometry of the design. The resulting structure suggests that photon absorptivity in the thin film silicon can be enhanced by as much as 100% over the uncoated layer. The proposed design is then fabricated using thin film deposition techniques, along with a control sample of bare silicon absorber for comparison. AFM imaging and spectrophotometry experiments are applied to image and record the surface roughness and measure the reflectivity spectrum of the sample. Using the measured reflectivity spectrum, we then use inverse optimization to estimate the realized thin film dimensions, deposition error and unwanted oxidation volume. At the end, we use a statistical Monte Carlo analysis as a second method of verification to demonstrate that the measured spectra are in accordance with the expected curves from simulation, and to estimate the effects of fabrication error.

  17. Relationships between Lead Halide Perovskite Thin-Film Fabrication, Morphology, and Performance in Solar Cells.

    Sharenko, Alexander; Toney, Michael F

    2016-01-20

    Solution-processed lead halide perovskite thin-film solar cells have achieved power conversion efficiencies comparable to those obtained with several commercial photovoltaic technologies in a remarkably short period of time. This rapid rise in device efficiency is largely the result of the development of fabrication protocols capable of producing continuous, smooth perovskite films with micrometer-sized grains. Further developments in film fabrication and morphological control are necessary, however, in order for perovskite solar cells to reliably and reproducibly approach their thermodynamic efficiency limit. This Perspective discusses the fabrication of lead halide perovskite thin films, while highlighting the processing-property-performance relationships that have emerged from the literature, and from this knowledge, suggests future research directions. PMID:26588594

  18. PEDOT:PSS emitters on multicrystalline silicon thin-film absorbers for hybrid solar cells

    Junghanns, Marcus; Plentz, Jonathan; Andrä, Gudrun; Gawlik, Annett; Höger, Ingmar; Falk, Fritz

    2015-02-01

    We fabricated an efficient hybrid solar cell by spin coating poly(3,4-ethylene-dioxythiophene):polystyrenesulfonate (PEDOT:PSS) on planar multicrystalline Si (mc-Si) thin films. The only 5 μm thin Si absorber layers were prepared by diode laser crystallization of amorphous Si deposited by electron beam evaporation on glass. On these absorber layers, we studied the effect of SiOx and Al2O3 terminated Si surfaces. The short circuit density and power conversion efficiency (PCE) of the mc-Si/Al2O3/PEDOT:PSS solar cell increase from 20.6 to 25.4 mA/cm2 and from 7.3% to 10.3%, respectively, as compared to the mc-Si/SiOx/PEDOT:PSS cell. Al2O3 lowers the interface recombination and improves the adhesion of the polymer film on the hydrophobic mc-Si thin film. Open circuit voltages up to 604 mV were reached. This study demonstrates the highest PCE so far of a hybrid solar cell with a planar thin film Si absorber.

  19. PEDOT:PSS emitters on multicrystalline silicon thin-film absorbers for hybrid solar cells

    Junghanns, Marcus; Plentz, Jonathan, E-mail: jonathan.plentz@ipht-jena.de; Andr, Gudrun; Gawlik, Annett; Hger, Ingmar; Falk, Fritz [Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena (Germany)

    2015-02-23

    We fabricated an efficient hybrid solar cell by spin coating poly(3,4-ethylene-dioxythiophene):polystyrenesulfonate (PEDOT:PSS) on planar multicrystalline Si (mc-Si) thin films. The only 5??m thin Si absorber layers were prepared by diode laser crystallization of amorphous Si deposited by electron beam evaporation on glass. On these absorber layers, we studied the effect of SiO{sub x} and Al{sub 2}O{sub 3} terminated Si surfaces. The short circuit density and power conversion efficiency (PCE) of the mc-Si/Al{sub 2}O{sub 3}/PEDOT:PSS solar cell increase from 20.6 to 25.4?mA/cm{sup 2} and from 7.3% to 10.3%, respectively, as compared to the mc-Si/SiO{sub x}/PEDOT:PSS cell. Al{sub 2}O{sub 3} lowers the interface recombination and improves the adhesion of the polymer film on the hydrophobic mc-Si thin film. Open circuit voltages up to 604?mV were reached. This study demonstrates the highest PCE so far of a hybrid solar cell with a planar thin film Si absorber.

  20. Superior light trapping in thin film silicon solar cells through nano imprint lithography

    Soppe, W.J.; Dorenkamper, M.S.; Schropp, R.E.I.; Pex, P.P.A.C.

    2013-10-15

    ECN and partners have developed a fabrication process based on nanoimprint lithography (NIL) of textures for light trapping in thin film solar cells such as thin-film silicon, OPV, CIGS and CdTe. The process can be applied in roll-to-roll mode when using a foil substrate or in roll-to-plate mode when using a glass substrate. The lacquer also serves as an electrically insulating layer for cells if steel foil is used as substrate, to enable monolithic series interconnection. In this paper we will show the superior light trapping in thin film silicon solar cells made on steel foil with nanotextured back contacts. We have made single junction a-Si and {mu}c-Si and a-Si/{mu}c-Si tandem cells, where we applied several types of nano-imprints with random and periodic structures. We will show that the nano-imprinted back contact enables more than 30% increase of current in comparison with non-textured back contacts and that optimized periodic textures outperform state-of-the-art random textures. For a-Si cells we obtained Jsc of 18 mA/cm{sup 2} and for {mu}c-Si cells more than 24 mA/cm{sup 2}. Tandem cells with a total Si absorber layer thickness of only 1350 nm have an initial efficiency of 11%.

  1. Impact of contamination on hydrogenated amorphous silicon thin films & solar cells

    Wördenweber, Jan

    2011-01-01

    This thesis deals with atmospheric contamination and cross-contamination of boron (single-chamber process) of the intrinsic absorber layer (i-layer) of p-i-n thin film solar cells based on hydrogenated amorphous silicon. The atmospheric contaminations were introduced by means of intentional leaks. Hereby, the focus is on the influence of contamination species (oxygen & nitrogen), quantity of contamination (leak flow), source of contamination (leaks at chamber wall or in the process gas pipe),...

  2. Bimodal nanostructured TiO2 thin films for dye sensitized solar cells

    Zukalová, Markéta; Kavan, Ladislav; Zukal, Arnošt; Graetzel, M.

    Málaga : BrownWalker Press, 2012. s. 99-99. ISBN 978-1-61233-558-2. [EMR 2012 : The Energy and Materials Research Conference. 20.06.2012-22.06.2012, Torremolinos] R&D Projects: GA ČR(CZ) GAP108/12/0814 Institutional support: RVO:61388955 Keywords : TiO2 * thin films * dye-sensitized solar cell Subject RIV: CG - Electrochemistry

  3. Light trapping in thin-film solar cells measured by Raman spectroscopy

    Ledinský, Martin; Moulin, E.; Bugnon, G.; Ganzerová, Kristína; Vetushka, Aliaksi; Meillaud, F.; Fejfar, Antonín; Ballif, C.

    2014-01-01

    Roč. 105, č. 11 (2014), "111106-1"-"111106-4". ISSN 0003-6951 R&D Projects: GA ČR GA14-15357S; GA MŠk(CZ) LM2011026; GA MŠk 7E12029 EU Projects: European Commission(XE) 283501 - FAST TRACK Institutional support: RVO:68378271 Keywords : light trapping * microcrystalline silicon * thin film solar cell * Raman spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.302, year: 2014

  4. Scope of VHF plasma deposition for thin-film silicon solar cells

    Keppner, H.; Kroll, U.; Torres, P.; Meier, J.; Fischer, D.; Goetz, M; Tscharner, R.; Shah, A.

    2008-01-01

    The world-wide attempts in obtaining thin-film crystalline silicon are reviewed. Based on literature published so far, it appears that high-temperature manufacturing steps seem to be unavoidable for obtaining high conversion efficiencies of crystalline silicon based solar cells. High process temperatures are in contradiction for the use of low-cost substrates like e.g. glass or aluminium. Such substrates, however, are essential for obtaining low module manufacturing costs. The very high frequ...

  5. Resonances and absorption enhancement in thin film silicon solar cells with periodic interface texture

    Haug, F.-J.; Sderstrm, K; Naqavi, A.; Ballif, C.

    2011-01-01

    We study absorption enhancement by light scattering at periodically textured interfaces in thin film silicon solar cells. We show that the periodicity establishes resonant coupling to propagating waveguide modes. Ideally, such modes propagate in the high index silicon film where they are eventually absorbed, but waveguide modes exist also in the transparent front contact layer if the product of its refractive index and thickness exceeds half the wavelength. Taking into account that the absorp...

  6. Multi-Material Front Contact for 19% Thin Film Solar Cells

    Joop van Deelen; Yasemin Tezsevin; Marco Barink

    2016-01-01

    The trade-off between transmittance and conductivity of the front contact material poses a bottleneck for thin film solar panels. Normally, the front contact material is a metal oxide and the optimal cell configuration and panel efficiency were determined for various band gap materials, representing Cu(In,Ga)Se2 (CIGS), CdTe and high band gap perovskites. Supplementing the metal oxide with a metallic copper grid improves the performance of the front contact and aims to increase the efficiency...

  7. Disorder Improves Light Absorption in Thin Film Silicon Solar Cells with Hybrid Light Trapping Structure

    Yanpeng Shi; Xiaodong Wang; Fuhua Yang

    2016-01-01

    We present a systematic simulation study on the impact of disorder in thin film silicon solar cells with hybrid light trapping structure. For the periodical structures introducing certain randomness in some parameters, the nanophotonic light trapping effect is demonstrated to be superior to their periodic counterparts. The nanophotonic light trapping effect can be associated with the increased modes induced by the structural disorders. Our study is a systematic proof that certain disorder is ...

  8. Microscopic characterizations of nanostructured silicon thin films for solar cells

    Fejfar, Antonín; Klapetek, P.; Zlámal, J.; Vetushka, Aliaksi; Ledinský, Martin; Kočka, Jan

    Warrendale : MRS, 2011 - (Yan, B.; Higashi, S.; Tsai, C.; Wang, Q.; Gleskova, H.), s. 313-321 ISBN 9781605112985. - (MRS Symposium Proceeding. 1321). [Materials Research Society Spring Meeting. San Francisko (US), 25.04.2011-29.04.2011] R&D Projects: GA MŠk(CZ) LC06040; GA MŠk(CZ) MEB061012; GA AV ČR KAN400100701; GA MŠk LC510 Grant ostatní: 7. Framework programme EU(XE) no. 240826 Institutional research plan: CEZ:AV0Z10100521 Keywords : silicon * scanning probe methods * solar cells Subject RIV: BM - Solid Matter Physics ; Magnetism

  9. Microcrystalline silicon for thin-film solar cells

    Gordijn, Aad

    2005-01-01

    Microcrystalline silicon (μc-Si:H) is a material that is promising for application in solar cells and that has interesting material properties. This thesis reports on the study of the plasma properties in the growth process, the optoelectronic material properties, and the device application of both doped and intrinsic μc-Si:H. Microcrystalline silicon p- and n-type doped layers have been developed by layer-by-layer (LbL) deposition using very high frequency chemical vapor deposition (VHF PECV...

  10. Electrical conductivity of chlorophyll with poly thiophene thin film as a bulk heterojunction solar cell

    Full text: In this work, electrical conductivity of the combinations mixture with different ratio of Poly thiophene (PT) and Chlorophyll (CHLO) thin film as a bulk heterojunction solar cell was studied. Spin coating technique was used to deposit the combination of PT and CHLO thin film on the Aurum (Au) layer which acts as a substrate. The optical characterization of thin film was measured using UV-Visible Spectrophotometer and four point probes were used to determine the film electrical properties in the dark and under the light. From the optical absorption study, the combination mixture between PT and CHLO altered the energy band gap of the thin film. The increasing of the mixture ratio of both solutions decreased the electrical conductivity in the dark and also under light. Under the light, the electrical conductivity of combine mixture shows the increasing with the increased of light intensity. The lowest mixture ratio shows the highest electrical conductivity ± 1.389 S/m under dark and increased with the increasing of the light intensity. (author)

  11. High efficiency thin-film GaAs solar cells

    Zwerdling, S.; Wang, K. L.; Yeh, Y. C. M.

    1981-01-01

    The paper demonstrates the feasibility of producing high-efficiency GaAs solar cells with high power-to-weight ratios by organic metallic chemical vapor deposition (OM-CVD) growth of thin epi-layers on suitable substrates. An AM1 conversion efficiency of 18% (14% AM0), or 17% (13% AM0) with a 5% grid coverage is achieved for a single-crystal GaAs n(+)/p cell grown by OM-CVD on a Ge wafer. Thin GaAs epi-layers OM-CVD grown can be fabricated with good crystallographic quality using a Si-substrate on which a thin Ge epi-interlayer is first deposited by CVD from GeH4 and processed for improved surface morphology

  12. Impurity-doped ZnO Thin Films Prepared by Physical Deposition Methods Appropriate for Transparent Electrode Applications in Thin-film Solar Cells

    This paper describes the development of transparent conducting impurity-doped ZnO thin films that would be appropriate for applications as transparent electrodes in thin-film solar cells. Transparent conducting Al-, B- and Ga-doped ZnO (AZO, BZO and GZO) thin films were prepared in a thickness range from 500 to 2000 nm on glass substrates at 200C using various physical deposition methods: BZO films with vacuum arc plasma evaporation, AZO and GZO films with different types of magnetron sputtering depositions (MSDs) and all films with pulsed laser deposition (PLD). The suitability and stability of the electrical properties and, in addition, the suitability of the light scattering characteristics and surface texture formation were investigated in the prepared thin films. In particular, the suitability and stability evaluation was focused on the use of AZO, BZO and GZO thin films prepared by doping each impurity at an appropriate content to attain the lowest resistivity. The higher Hall mobility obtained in impurity-doped ZnO thin films with a resistivity on the order of 10?4 ?cm was related more to the content, i.e., the obtained carrier concentration, rather than the kind of impurity doped into the films. The stability of resistivity of the BZO thin films in long-term moisture-resistance tests (in air at 85% relative humidity and 85C) was found to be lower than that of the AZO and GZO thin films. The surface texture formation was carried out by wet-chemical etching (in a 0.1% HCl solution at 25C) conducted either before or after being heat-treated either with rapid thermal annealing (RTA) or without RTA. The suitability of the light scattering characteristics and the surface texture formation obtainable by wet-chemical etching (for use in transparent electrode applications) was considerably dependent on the deposition method used as well as whether the wet-chemical etching was conducted with or without RTA. A significant improvement of both transmittance and haze value at wavelengths up to about 1200 nm in the near-infrared region was attained in surface-textured AZO films that were prepared by r.f. power superimposed d.c. MSD as well as etched after being heat treated with RTA at 500C for 5 min in air. The obtained suitability and stability in impurity-doped ZnO thin films were related more to the content rather than the kind of impurity doped into the films as well as to the deposition method used.

  13. Thin-film silicon solar cell development on imprint-textured glass substrates

    Paetzold, Ulrich Wilhelm; Zhang, Wendi [Institut fr Energie- und Klimaforschung 5 Photovoltaics, Forschungszentrum Jlich GmbH, D-52425 Jlich (Germany); Prmpers, Michael [Peter Grnberg Institut 8 Bioelectronics, Forschungszentrum Jlich GmbH, D-52425 Jlich (Germany); Kirchhoff, Joachim; Merdzhanova, Tsvetelina; Michard, Stephan; Carius, Reinhard; Gordijn, Aad [Institut fr Energie- und Klimaforschung 5 Photovoltaics, Forschungszentrum Jlich GmbH, D-52425 Jlich (Germany); Meier, Matthias, E-mail: ma.meier@fz-juelich.de [Institut fr Energie- und Klimaforschung 5 Photovoltaics, Forschungszentrum Jlich GmbH, D-52425 Jlich (Germany)

    2013-05-15

    Highlights: ? Microcrystalline thin-film silicon solar cells fabricated on textured glass. ? Replication of light trapping textures with a UV-nanoimprint process. ? Excellent replication precision with soft polymer mold. ? Thin TCO front contacts (60 nm) for enhanced incoupling of incident light. ? Impact of high series resistance of front contacts avoided by reduced cell width. -- Abstract: In this work, we report on the fabrication of microcrystalline thin-film silicon solar cells on textured glass substrates. The development of transparent and conductive front contacts for these solar cells is presented. State-of-the-art random textures for light-trapping were replicated into a glass-like resist on glass substrates with an imprint process. We applied an industrial relevant soft polymer mold that gives excellent replication accuracy. The necessity of applying thin front contacts for enhanced incoupling of the incident light is shown. An increased series resistance of these thin front contacts caused a decrease of the fill factor of the solar cells. One way to surpass this decrease in fill factor by reducing the solar cell width is demonstrated. In addition, the light-trapping and the light-incoupling for solar cells deposited on three different types of random textures were compared.

  14. Thin-film silicon solar cell development on imprint-textured glass substrates

    Highlights: ? Microcrystalline thin-film silicon solar cells fabricated on textured glass. ? Replication of light trapping textures with a UV-nanoimprint process. ? Excellent replication precision with soft polymer mold. ? Thin TCO front contacts (60 nm) for enhanced incoupling of incident light. ? Impact of high series resistance of front contacts avoided by reduced cell width. -- Abstract: In this work, we report on the fabrication of microcrystalline thin-film silicon solar cells on textured glass substrates. The development of transparent and conductive front contacts for these solar cells is presented. State-of-the-art random textures for light-trapping were replicated into a glass-like resist on glass substrates with an imprint process. We applied an industrial relevant soft polymer mold that gives excellent replication accuracy. The necessity of applying thin front contacts for enhanced incoupling of the incident light is shown. An increased series resistance of these thin front contacts caused a decrease of the fill factor of the solar cells. One way to surpass this decrease in fill factor by reducing the solar cell width is demonstrated. In addition, the light-trapping and the light-incoupling for solar cells deposited on three different types of random textures were compared

  15. Full potential of radial junction Si thin film solar cells with advanced junction materials and design

    Qian, Shengyi; Misra, Soumyadeep; Lu, Jiawen; Yu, Zhongwei; Yu, Linwei; Xu, Jun; Wang, Junzhuan; Xu, Ling; Shi, Yi; Chen, Kunji; Roca i Cabarrocas, Pere

    2015-07-01

    Combining advanced materials and junction design in nanowire-based thin film solar cells requires a different thinking of the optimization strategy, which is critical to fulfill the potential of nano-structured photovoltaics. Based on a comprehensive knowledge of the junction materials involved in the multilayer stack, we demonstrate here, in both experimental and theoretical manners, the potential of hydrogenated amorphous Si (a-Si:H) thin film solar cells in a radial junction (RJ) configuration. Resting upon a solid experimental basis, we also assess a more advanced tandem RJ structure with radially stacking a-Si:H/nanocrystalline Si (nc-Si:H) PIN junctions, and show that a balanced photo-current generation with a short circuit current density of Jsc = 14.2 mA/cm2 can be achieved in a tandem RJ cell, while reducing the expensive nc-Si:H absorber thickness from 1-3 μ m (in planar tandem cells) to only 120 nm. These results provide a clearly charted route towards a high performance Si thin film photovoltaics.

  16. Thin-film silicon solar cells. A review and selected trends

    A case is developed for considering silicon as the prime medium-term candidate for semiconductor photovoltaic cells; the argumentation is based on other materials not being abundantly available, highly toxic and/or very expensive. Crystalline silicon solar cells have excellent efficiencies, however, according to data presented by the authors on material fluxes and energy consumption there are serious bottlenecks for this technique with respect to future large-scale applications both from an economical as well as from an ecological point of view. Thus, the authors consider thin-film silicon solar cells as the main option for large-scale energy applications in the foreseeable future. Thin-film silicon solar cells are either polycrystalline or amorphous. The first category is gaining in interest at this moment, but major technological problems remain unresolved, e.g., growth of a high-quality crystalline structure on foreign (low-cost) substrates, reduction of deposition temperature and increase of deposition rate. The second category has so far yielded only limited stable efficiencies, although progress has been recently achieved in improving the stability of solar cells using stacked or tandem/triple structures. Novel approaches to further improve the stable efficiencies, such as using low-level doping profiles within the i-layer of the p-i-n solar cell, are listed. Entirely microcrystalline p-i-n solar cells that are stable and can be deposited at low temperatures (220C) with rates up to 1 A/s by the VHF plasma deposition technique are described as further, recent contribution to thin-film silicon photovoltaic technology

  17. 3D photonic crystal intermediate reflector for micromorph thin-film tandem solar cell

    Uepping, Johannes; Miclea, Paul T.; Wehrspohn, Ralf B. [Institute of Physics, Martin-Luther-University of Halle-Wittenberg, Heinrich-Damerow-Str. 4, 06120 Halle (Germany); Rockstuhl, Carsten; Lederer, Falk [Institute of Condensed Matter Theory and Solid States Optics, Friedrich Schiller University Jena, 07743 Jena (Germany); Peters, Marius [Freiburg Centre for Material Research, University of Freiburg, 79104 Freiburg (Germany); Steidl, Lorenz; Zentel, Rudolf [Dept. of Chemistry, Pharmacy and Earth Science, Johannes Gutenberg University of Mainz, Duesbergweg 10-14 (Germany); Lee, Seung-Mo; Knez, Mato [Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Germany); Lambertz, Andreas; Carius, Reinhard [Institute of Energy Research, IEF-5 Photovoltaics, Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); Bielawny, Andreas

    2008-12-15

    The concept of 3D photonic intermediate reflectors for micromorph silicon tandem solar cells has been investigated. In thin-film silicon tandem solar cells consisting of amorphous and microcrystalline silicon with two junctions of a-Si/{mu}c-Si, efficiency enhancements can be achieved by increasing the current density in the a-Si top cell. It is one goal to provide an optimized current matching at high current densities. For an ideal photon-management between top and bottom cell, a spectrally selective intermediate reflective layer (IRL) is necessary, which is less dependent of the angle of incidence than state-of-the-art thickness dependent massive interlayers. The design, preparation and characterization of a 3D photonic thin-film filter device for this purpose has been pursued straight forward in simulation and experimental realization. The inverted opal is capable of providing a suitable optical band stop with high reflectance and the necessary long wavelength transmittance as well and provides further options for improved light trapping. We have determined numerically the relative efficiency enhancement of an a-Si/{mu}c-Si tandem solar cell using a conductive 3D-photonic crystal. We have further fabricated such structures by ZnO-replication of polymeric opals using chemical vapour deposition and atomic layer deposition techniques and present the results of their characterization. Thin film photonic IRL have been prepared at the rear side of a-Si solar cells. Completed with a back contact, this is the first step to integrate this novel technology into an a-Si/{mu}c-Si tandem solar cell process. The spectral response of the cell is presented and compared with reference cells. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Performance evaluation of thin film silicon solar cell based on dual diffraction grating.

    Dubey, Raghvendra Sarvjeet; Saravanan, Sigamani; Kalainathan, Sivaperuman

    2014-12-01

    Light-trapping structures are more demanding for optimal light absorption in thin film silicon solar cells. Accordingly, new design engineering of solar cells has been emphasized and found to be effective to achieve improved performance. This paper deals with a design of thin film silicon solar cells and explores the influence of bottom grating and combination of top and bottom (dual) grating as a part of back reflector with a distributed Bragg reflector (DBR). Use of metal layer as a part of back reflector has found to be promising for minimum requirement of DBR pairs. The effect of grating and anti-reflection coating thicknesses are also investigated for absorption enhancement. With optimization, high performance has been achieved from dual grating-based solar cell with a relative enhancement in short-circuit current approximately 68% while it was approximately 55% in case of bottom grating-based solar cell. Our designing efforts show enhanced absorption of light in UV and infrared part of solar spectrum. PMID:26088994

  19. Experimental study of Cu2ZnSnS4 thin films for solar cells

    Flammersberger, Hendrik

    2010-01-01

    Cu2ZnSnS4 (CZTS) is a semiconductor with a direct band gap of about 1,5 eV and anabsorption coefficient of 10^4 cm^-1, and is for this reason a potential thin film solarcell material. Demonstrated efficiencies of up to 6,8% as well as use of cheap andabundant elements make CZTS a promising alternative to current solar cells.The aim of this study was to fabricate and characterize CZTS films and to evaluatetheir performance in complete solar cells. For the fabrication of CZTS we applied atwo-st...

  20. Role of 2-D periodic symmetrical nanostructures in improving efficiency of thin film solar cells

    Zhang, Wei; Jiang, Liyong; Li, Xiangyin

    2016-01-01

    We systematically investigated several different nanostructures in crystalline silicon (c-Si) thin film solar cells and then proposed a brand-new structure with two dimensional (2-D) periodic dielectric cylinders on the top and annular metal columns on bottom surface to enhance the optical harvesting. The periodic symmetrical nanostructures affect the solar cell efficiency due to the grating diffraction effect of dielectric columns and surface plasmon polaritons (SPPs) effect induced by metal nanostructures at the dielectric-metal interface. About 52.1% more optical absorption and 33.3% more power conversion efficiency are obtained, and the maximum short current reaches to 33.24 mA/cm2.

  1. Plasma monitoring and PECVD process control in thin film silicon-based solar cell manufacturing

    Gabriel Onno

    2014-02-01

    Full Text Available A key process in thin film silicon-based solar cell manufacturing is plasma enhanced chemical vapor deposition (PECVD of the active layers. The deposition process can be monitored in situ by plasma diagnostics. Three types of complementary diagnostics, namely optical emission spectroscopy, mass spectrometry and non-linear extended electron dynamics are applied to an industrial-type PECVD reactor. We investigated the influence of substrate and chamber wall temperature and chamber history on the PECVD process. The impact of chamber wall conditioning on the solar cell performance is demonstrated.

  2. Computational and experimental study of a multi-layer absorptivity enhanced thin film silicon solar cell

    We report on the computational design, fabrication and validation of a multi-layer silicon based thin film solar cell. The cell structure consists of a thin absorber layer of amorphous silicon deposited on a back-reflector aluminum layer and coated on top with ITO transparent conductive oxide. The structure is mounted on a glass substrate. We first use constrained optimization techniques along with numerical solvers of the electromagnetic equations (i.e. FDTD) to tune the geometry of the design. The resulting structure suggests that photon absorptivity in the thin film silicon can be enhanced by as much as 100% over the uncoated layer. The proposed design is then fabricated using thin film deposition techniques, along with a control sample of bare silicon absorber for comparison. AFM imaging and spectrophotometry experiments are applied to image and record the surface roughness and measure the reflectivity spectrum of the sample. Using the measured reflectivity spectrum, we then use inverse optimization to estimate the realized thin film dimensions, deposition error and unwanted oxidation volume. At the end, we use a statistical Monte Carlo analysis as a second method of verification to demonstrate that the measured spectra are in accordance with the expected curves from simulation, and to estimate the effects of fabrication error. - Highlights: • Design, fabrication and validation of multi-layer silicon solar cell are studied. • The cell consists of aluminum, amorphous silicon and ITO layers. • The proposed designs are fabricated by deposition techniques. • Inverse optimization is used to estimate the realized dimensions and errors

  3. Thin film solar cell and its manufacturing method; Hakumaku taiyo denchi oyobi sono seizo hoho

    Uda, K.; Murata, M. [Mitsubishi Heavy Industries Ltd., Nagasaki (Japan). Nagasaki Technical Inst.

    1996-03-08

    Masked film formation and the laser etching method are used for patterning of each film composing a thin film solar cell. The masked film formation method requires a positioning process in order to make contact the underlying film with the masking plate and has a weakness that the film is liable to suffer damage. The laser etching method requires a positioning of irradiating laser beam in accordance with the pattern of the underlying film. This invention presents a configuration to collect the charge generated in the transparent electrode side through penetrating pores provided on the metal substrate on the backside metal film so as to reduce the power loss with the transparent electrode. By the installation of a large number of the penetrating pores on the metal substrate, the positioning of the semiconductor thin film, the transparent electrode and the backside metal film is unnecessary and a thin film solar cell of a large area can be manufactured merely by film formation. 9 figs.

  4. Design principle for absorption enhancement with nanoparticles in thin-film silicon solar cells

    The use of nanoparticles in solar cells has created many controversies. In this paper, different mechanisms of nanoparticles with different materials with diameters varying from 50 to 200 nm, surface coverage at 5, 20, and 60 %, and different locations are analyzed systematically for efficient light trapping in a thin-film c-Si solar cell. Mie theory and the finite difference time domain method are used for analysis to give a design principle with nanoparticles for the solar cell application. Metals exhibit plasmonic resonances and angular scattering, while dielectrics show anti-reflection and scattering in the incident direction. A table is given to summarize the advantages and disadvantages in different conditions. The silicon absorption enhancement with nanoparticles on top is mainly in the shorter wavelengths below 700 nm, and both Al and SiO2 nanoparticles with diameter around 100 nm show the most significant enhancement. The silicon absorption enhancement with embedded nanoparticles takes place in the longer wavelengths over 700 nm, and Ag and SiO2 nanoparticles with larger diameter around 200 nm perform better. However, the light absorbed by Ag nanoparticles will be converted to heat and will lead to decrease in cell efficiency; hence, the choice of metallic nanoparticles in applications to solar cells should be carefully considered. The design principle proposed in this work gives a guideline by choosing reasonable parameters for the different requirements in the application of thin-film solar cells

  5. Ethyl-1-hexanol based screen-printed titania thin films for dye-sensitized solar cells

    Tsoukleris, D.S.; Arabatzis, I.M.; Chatzivasiloglou, E.; Kontos, A.I.; Belessi, V.; Falaras, P. [Institute of Physical Chemistry, NCSR-Demokritos, 153 10 Aghia Paraskevi, Athens (Greece); Bernard, M.C. [UPR 15 du CNRS Physique des Interfaces et Electrochimie, Universite Pierre et Marie Curie, 75252 Paris Cedex 05 (France)

    2005-10-01

    Nanocrystalline titania thin films were prepared by screen printing in order to efficiently control and optimize the main step of the dye-sensitized solar cells (DSSCs) fabrication process. Different compositions of nanocrystalline titanium dioxide screen-printing pastes are described, based on 2-ethyl-1-hexanol solvent and commercial Degussa P25 TiO{sub 2}. The rheological properties of the prepared pastes are presented as the crucial parameter of the deposition procedure. The produced titania thin films are extensively characterized by means of spectroscopy (Raman, XRD) and microscopy (SEM, AFM). The performance (induced photon-to-current efficiency-IPCE% and overall energy conversion efficiency-{eta}%) of the corresponding DSSCs is also reported. (author)

  6. Identification of critical stacking faults in thin-film CdTe solar cells

    Cadmium telluride (CdTe) is a p-type semiconductor used in thin-film solar cells. To achieve high light-to-electricity conversion, annealing in the presence of CdCl2 is essential, but the underlying mechanism is still under debate. Recent evidence suggests that a reduction in the high density of stacking faults in the CdTe grains is a key process that occurs during the chemical treatment. A range of stacking faults, including intrinsic, extrinsic, and twin boundary, are computationally investigated to identify the extended defects that limit performance. The low-energy faults are found to be electrically benign, while a number of higher energy faults, consistent with atomic-resolution micrographs, are predicted to be hole traps with fluctuations in the local electrostatic potential. It is expected that stacking faults will also be important for other thin-film photovoltaic technologies

  7. Identification of critical stacking faults in thin-film CdTe solar cells

    Yoo, Su-Hyun; Walsh, Aron, E-mail: a.walsh@bath.ac.uk [Global E3 Institute, Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Centre for Sustainable Chemical Technologies and Department of Chemistry, University of Bath, Bath BA2 7AY (United Kingdom); Butler, Keith T. [Centre for Sustainable Chemical Technologies and Department of Chemistry, University of Bath, Bath BA2 7AY (United Kingdom); Soon, Aloysius [Global E3 Institute, Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Abbas, Ali; Walls, John M., E-mail: j.m.wall@loughborough.ac.uk [Centre for Renewable Energy Systems Technology, School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom)

    2014-08-11

    Cadmium telluride (CdTe) is a p-type semiconductor used in thin-film solar cells. To achieve high light-to-electricity conversion, annealing in the presence of CdCl{sub 2} is essential, but the underlying mechanism is still under debate. Recent evidence suggests that a reduction in the high density of stacking faults in the CdTe grains is a key process that occurs during the chemical treatment. A range of stacking faults, including intrinsic, extrinsic, and twin boundary, are computationally investigated to identify the extended defects that limit performance. The low-energy faults are found to be electrically benign, while a number of higher energy faults, consistent with atomic-resolution micrographs, are predicted to be hole traps with fluctuations in the local electrostatic potential. It is expected that stacking faults will also be important for other thin-film photovoltaic technologies.

  8. Thin-Film Solar Cells Based on the Polycrystalline Compound Semiconductors CIS and CdTe

    Dieter Bonnet

    2007-09-01

    Full Text Available Thin-film photovoltaic modules based on Cu-In-Ga-Se-S (CIS and CdTe are already being produced with high-quality and solar conversion efficiencies of around 10%, with values up to 14% expected in the near future. The integrated interconnection of single cells into large-area modules of 0.6×1.2m2 enables low-cost mass production, so that thin-film modules will soon be able to compete with conventional silicon-wafer-based modules. This contribution provides an overview of the basic technologies for CdTe and CIS modules, the research and development (R&D issues, production technology and capacities, the module performance in long-term outdoor testing, and their use in installations.

  9. Sustainability of photovoltaics. The case for thin-film solar cells

    To ensure photovoltaics become a major sustainable player in a competitive power-generation market, they must provide abundant, affordable electricity, with environmental impacts drastically lower than those from conventional power generation. The recent reduction in the cost of 2nd generation thin-film PV is remarkable, meeting the production milestone of $1 per watt in the fourth quarter of 2008. This achievement holds great promise for the future. However, the questions remaining are whether the expense of PV modules can be lowered further, and if there are resource- and environmental-impact constraints to growth. I examine the potential of thin-films in a prospective life-cycle analysis, focusing on direct costs, resource availability, and environmental impacts. These three aspects are closely related; developing thinner solar cells and recycling spent modules will become increasingly important in resolving cost, resource, and environmental constraints to large scales of sustainable growth. (author)

  10. Sinusoidal nanotextures for light management in silicon thin-film solar cells

    Köppel, G.; Rech, B.; Becker, C.

    2016-04-01

    Recent progresses in liquid phase crystallization enabled the fabrication of thin wafer quality crystalline silicon layers on low-cost glass substrates enabling conversion efficiencies up to 12.1%. Because of its indirect band gap, a thin silicon absorber layer demands for efficient measures for light management. However, the combination of high quality crystalline silicon and light trapping structures is still a critical issue. Here, we implement hexagonal 750 nm pitched sinusoidal and pillar shaped nanostructures at the sun-facing glass-silicon interface into 10 μm thin liquid phase crystallized silicon thin-film solar cell devices on glass. Both structures are experimentally studied regarding their optical and optoelectronic properties. Reflection losses are reduced over the entire wavelength range outperforming state of the art anti-reflective planar layer systems. In case of the smooth sinusoidal nanostructures these optical achievements are accompanied by an excellent electronic material quality of the silicon absorber layer enabling open circuit voltages above 600 mV and solar cell device performances comparable to the planar reference device. For wavelengths smaller than 400 nm and higher than 700 nm optical achievements are translated into an enhanced quantum efficiency of the solar cell devices. Therefore, sinusoidal nanotextures are a well-balanced compromise between optical enhancement and maintained high electronic silicon material quality which opens a promising route for future optimizations in solar cell designs for silicon thin-film solar cells on glass.

  11. Five roads towards increased optical absorption and high stable efficiency for thin film silicon solar cells

    Vaněček, Milan; Poruba, Aleš; Remeš, Zdeněk; Holovský, Jakub; Purkrt, Adam; Babchenko, Oleg; Hruška, Karel; Meier, J.; Kroll, U.

    Munich : WIP- Renewable Energies, 2009 - (Sinke, W.; Ossenbrink, H.; Helm, P.), 2286-2289 ISBN 3-936338-25-6. [European Photovoltaic Solar Energy Conference /24./. Hamburg (DE), 21.09.2009-25.09.2009] R&D Projects: GA MŠk(CZ) 7E09057 EU Projects: European Commission(XE) 214134 - N2P; European Commission(XE) 19670 - ATHLET Institutional research plan: CEZ:AV0Z10100521 Keywords : thin film silicon solar cells * amorphous silicon * nanostructure * high stable efficiency Subject RIV: BM - Solid Matter Physics ; Magnetism

  12. Water vapour passivation of poly-Si thin film solar cells

    Pikna, Peter; Fejfar, Antonín; Píč, Vlastimil; Müller, Martin; Ledinský, Martin; Vetushka, Aliaksi; Kočka, Jan

    München : WIP Wirtschaft und Infrastruktur GmbH & Co Planungs KG, 2012 - (Nowak, S.), s. 2393-2395 ISBN 3-936338-28-0. [European Photovoltaic Solar Energy Conference and Exhibition (PVSEC) /17./. Frankfurt (DE), 24.09.2012-28.09.2012] R&D Projects: GA MŠk 7E10061; GA MPO FR-TI2/736; GA MŠk(CZ) LM2011026 EU Projects: European Commission(XE) 240826 - POLYSIMODE Institutional research plan: CEZ:AV0Z10100521 Keywords : polycrystalline * silicon * thin film solar cell * water vapour passivation * in situ investigation * Suns-Voc Subject RIV: BM - Solid Matter Physics ; Magnetism

  13. Advances in Thin-Film Si Solar Cells by Means of SiOx Alloys

    Lucia V. Mercaldo

    2016-03-01

    Full Text Available The conversion efficiency of thin-film silicon solar cells needs to be improved to be competitive with respect to other technologies. For a more efficient use of light across the solar spectrum, multi-junction architectures are being considered. Light-management considerations are also crucial in order to maximize light absorption in the active regions with a minimum of parasitic optical losses in the supportive layers. Intrinsic and doped silicon oxide alloys can be advantageously applied within thin-film Si solar cells for these purposes. Intrinsic a-SiOx:H films have been fabricated and characterized as a promising wide gap absorber for application in triple-junction solar cells. Single-junction test devices with open circuit voltage up to 950 mV and ~1 V have been demonstrated, in case of rough and flat front electrodes, respectively. Doped silicon oxide alloys with mixed-phase structure have been developed, characterized by considerably lower absorption and refractive index with respect to standard Si-based films, accompanied by electrical conductivity above 10−5 S/cm. These layers have been successfully applied both into single-junction and micromorph tandem solar cells as superior doped layers with additional functionalities.

  14. Absorption Enhancement of Thin-film Solar Cell with Rectangular Ag Nanoparticles

    Zongheng Yuan

    2014-01-01

    Full Text Available Solar power has gained a great deal of attention as a clean energy source with the potential to replace fossil fuel. Researchers have focused in increasing the efficiency of thin film solar cells. In this study, rectangular Ag nanoparticles were placed on the silicon layer of a silicon solar cell. The absorption enhancement of the silicon was systematically investigated via the Finite Difference Time Domain Method (FDTD. The improvement in silicon absorption of the solar cell because of the addition of Ag nanoparticles was studied by calculating the enhancement factor by using the Lumerical FDTD solutions simulation package. The results demonstrated that the light absorption was significantly improved because of the localized surface plasmon resonance of the Ag nanoparticles. The structure with rectangular Ag nanoparticles obtained the most efficient absorption enhancement compared with the sphere and cylinder Ag nanoparticles. The effects of nanoparticle parameters on the absorption enhancement were also thoroughly analyzed. The optimal absorption enhancement was achieved by adjusting the parameters of nanoparticles. The structure may be used to develop highly efficient thin film solar cells.

  15. Metallisation and Interconnection of e-Beam Evaporated Polycrystalline Silicon Thin-Film Solar Cells on Glass

    Taekyun Kim; Peter J. Gress; Sergey Varlamov

    2012-01-01

    One inherent advantage of thin-film technology is the possibility of using monolithic integration for series interconnection of individual cells within large-area modules. Polycrystalline silicon thin-film solar cells do not rely on transparent conducting oxide layers as the high sheet conductivity of the emitter and BSF layers enables the lateral flow of current from the film to the metal contacts. This paper presents a new method for the fabrication of e-beam evaporated polycrystalline thin...

  16. Nanotextured thin film silicon solar cells:optical model

    Špringer, Jiří; Poruba, Aleš; Fejfar, Antonín; Vaněček, Milan; Feitknecht, L.; Wyrsch, N.; Meier, J.; Shah, A.

    London : James & James, 2000 - (Scheer, H.; McNelis, B.; Palz, W.; Ossenbrink, H.; Helm, P.), s. 434-437 ISBN 1-902916-18-2. [European Photovoltaic Solar Energy Conference /16./. Glasgow (GB), 01.05.2000-05.05.2000] Institutional research plan: CEZ:AV0Z1010914 Keywords : si-films * modeling * texturization Subject RIV: BM - Solid Matter Physics ; Magnetism

  17. Epitaxially grown crystalline silicon thin-film solar cells reaching 16.5% efficiency with basic cell process

    We report about the current performance of crystalline silicon thin-film (cSiTF) solar cells that are a very attractive alternative to conventional wafer-based silicon solar cells if sufficiently high cell efficiencies are achieved at acceptable cost of production. Applying a standard cell process (diffused POCl3 emitter, front contacts by photolithography, no surface texture) to thin-films deposited with a lab-type reactor, specifically designed for high-throughput photovoltaic applications, on highly-doped Cz substrates we routinely obtain efficiencies above 16%. On 1 ? cm FZ material substrates we reach efficiencies up to 18.0%, which is among the highest thin-film efficiencies ever reported. Additionally, a comparison to microelectronic-grade epitaxially grown cSiTF material underlines the excellent electrical quality of the epitaxial layers deposited.

  18. Synthesis of Cu2ZnSnS4 thin films by a precursor solution paste for thin film solar cell applications.

    Cho, Jin Woo; Ismail, Agus; Park, Se Jin; Kim, Woong; Yoon, Sungho; Min, Byoung Koun

    2013-05-22

    Cu2ZnSnS4 (CZTS) is a very promising semiconductor material when used for the absorber layer of thin film solar cells because it consists of only abundant and inexpensive elements. In addition, a low-cost solution process is applicable to the preparation of CZTS absorber films, which reduces the cost when this film is used for the production of thin film solar cells. To fabricate solution-processed CZTS thin film using an easily scalable and relatively safe method, we suggest a precursor solution paste coating method with a two-step heating process (oxidation and sulfurization). The synthesized CZTS film was observed to be composed of grains of a size of ~300 nm, showing an overall densely packed morphology with some pores and voids. A solar cell device with this film as an absorber layer showed the highest efficiency of 3.02% with an open circuit voltage of 556 mV, a short current density of 13.5 mA/cm(2), and a fill factor of 40.3%. We also noted the existence of Cd moieties and an inhomogeneous Zn distribution in the CZTS film, which may have been triggered by the presence of pores and voids in the CZTS film. PMID:23611655

  19. Nano imprint lithography of textures for light trapping in thin film silicon solar cells

    Soppe, W.J.; Dorenkamper, M.S.; Notta, J.B.; Pex, P.P.A.C. [ECN-Solliance, High Tech Campus 5, 5656 AE Eindhoven (Netherlands); Schipper, W.; Wilde, R. [Nanoptics GmbH, Innungsstrasse 5, 21244 Buchholz (Germany)

    2012-09-15

    Nano Imprint Lithography (NIL) is a versatile and commercially viable technology for fabrication of structures for light trapping in solar cells. We demonstrate the applicability of NIL in thin film silicon solar cells in substrate configuration, where NIL is used to fabricate a textured rear contact of the solar cells. We applied random structures, based on the natural texture of SnO:F grown by APCVD, and designed 2D periodic structures and show that for single junction {mu}c-Si cells these textured rear contacts lead to an increase of Jsc of more than 40 % in comparison to cells with flat rear contacts. Cells on optimized periodic textures showed higher fill factors which can be attributed to reduced microcrack formation, leading to less shunting in comparison to cells on random textures.

  20. Effects of potassium doping on solution processed kesterite Cu2ZnSnS4 thin film solar cells

    Tong, Zhengfu; Yan, Chang; Su, Zhenghua; Zeng, Fangqin; Yang, Jia; Li, Yi; Jiang, Liangxing; Lai, Yanqing; Liu, Fangyang

    2014-12-01

    Alkaline metals doping is one of the approaches for achieving high efficiency Cu(In,Ga)Se2 (CIGS) solar cell. Recently, potassium doping helps to break the record efficiency of CIGS solar cell doped with sodium. In this paper, we have investigated how incorporation of potassium can influence the properties of Cu2ZnSnS4 (CZTS) thin film and the performance of resulting solar cell. Our results showed that K doping can enhance the (112) preferred orientation, increase the grain size and reduce the second phase ZnS of the CZTS thin films. After K doping, despite of some drop of Voc for CZTS thin film solar cells, the Rs is decreased and the Jsc is improved markedly, and the solar cell efficiency is boosted.

  1. Characterization and optimization of ITO thin films for application in heterojunction silicon solar cells

    This investigation elucidates the properties of indium-tin oxide (ITO) thin films used as antireflection front electrodes in μc-Si/c-Si heterojunction (HJ) solar cells. The deposition conditions of ITO film by electron-gun evaporation were optimized for HJ solar cell applications. Microstructure, surface morphology, electrical and optical properties of these films were then characterized and analyzed. Next, the effects of substrate temperature on ITO film growth were discussed. The ITO thickness was optimized considering that the refractive index of μc-Si emitter layer optimizes its optical characteristics and HJ solar cell spectral response. The best HJ solar cell conversion efficiency was 16.4% with an open circuit voltage (Voc) of 0.645 V, fill factor (FF) of 0.73, and short circuit current density (Jsc) of 34.8 mA/cm2.

  2. Impact of the nanorod structure on the tandem thin-film solar cell.

    Tang, M; Chang, S T; Huang, C-X; Liu, Y T; Chen, Y H

    2011-07-01

    The novel thin-film solar cell was investigated with a nanorod structure that could solve the conflict between light absorption and carrier transport in the amorphous silicon (a-Si)/amorphous silicon-germanium (a-SiGe) tandem thin-film solar cell. This structure has an n-type a-Si nanorod array on the substrate, and an a-SiOx p-layer and an a-SiGe i-layer are sequentially grown along the surface of each n-type a-Si nanorod, for the bottom cell. After the above bottom-cell process, a similar process is used to fabricate an amorphous Si p-i-n top cell on the bottom cell. Under sunlight illumination, the light is absorbed along the vertical direction of the nanorod, but as the carrier transport is along the horizontal direction, the nanorod may absorb most of the sunlight. In the meantime, the solar cell is still thin enough for the effective transport of photogenerated carriers. PMID:22121598

  3. Efficiency improvement in Si thin film solar cells by employing composite nanocone-shaped grating structure

    Zhang, Zhen; Qiu, Bocang; Shao, Biao; Wu, Xuemei; Zhang, Ruiying

    2015-06-01

    The improvement in both the light absorption and energy conversion efficiency for thin film silicon solar cells by employing Al2O3/Si or SiN/Si composite nanocone-shaped gratings (CNCG) is theoretically studied. Our results show that the enhancement of the absorption and efficiency for Si thin film solar cells decorated by CNCG is mainly dominated by the nanocone-shaped gratings, but slightly fluctuated with the dielectric cladding layer and its thickness. The performance improvement is more significant using SiN/Si CNCG than using Al2O3/Si CNCG. The highest conversion efficiency of 6.60 and 9.53% are achieved in 1-m-thick solar cells with SiN (120 nm)/Si CNCG and 2-m-thick Si solar cells with SiN (90 nm)/Si CNCG respectively, which are compared to the conversion efficiencies of 3.23 and 3.96% for their planar counterparts. When the surface passivation effect is considered, the conversion efficiency should be enhanced more.

  4. Fabrication of solution processed 3D nanostructured CuInGaS₂ thin film solar cells.

    Chu, Van Ben; Cho, Jin Woo; Park, Se Jin; Hwang, Yun Jeong; Park, Hoo Keun; Do, Young Rag; Min, Byoung Koun

    2014-03-28

    In this study we demonstrate the fabrication of CuInGaS₂ (CIGS) thin film solar cells with a three-dimensional (3D) nanostructure based on indium tin oxide (ITO) nanorod films and precursor solutions (Cu, In and Ga nitrates in alcohol). To obtain solution processed 3D nanostructured CIGS thin film solar cells, two different precursor solutions were applied to complete gap filling in ITO nanorods and achieve the desirable absorber film thickness. Specifically, a coating of precursor solution without polymer binder material was first applied to fill the gap between ITO nanorods followed by deposition of the second precursor solution in the presence of a binder to generate an absorber film thickness of ∼1.3 μm. A solar cell device with a (Al, Ni)/AZO/i-ZnO/CdS/CIGS/ITO nanorod/glass structure was constructed using the CIGS film, and the highest power conversion efficiency was measured to be ∼6.3% at standard irradiation conditions, which was 22.5% higher than the planar type of CIGS solar cell on ITO substrate fabricated using the same precursor solutions. PMID:24569126

  5. Light trapping characteristics of glass substrate with hemisphere pit arrays in thin film Si solar cells

    Chen, Le; Wang, Qing-Kang; Wangyang, Pei-Hua; Huang, Kun; Shen, Xiang-Qian

    2015-04-01

    In this paper, the light trapping characteristics of glass substrate with hemisphere pit (HP) arrays in thin film Si solar cells are theoretically studied via a numerical approach. It is found that the HP glass substrate has good antireflection properties. Its surface reflectance can be reduced by 50% compared with planar glass. The HP arrays can make the unabsorbed light return to the absorbing layer of solar cells, and the ratio of second absorption approximately equals 30%. Thus, the glass substrate with the hemisphere pit arrays (HP glass) can effectively reduce the total reflectivity of a solar cell from 20% to 13%. The HP glass can also prolong the optical path length. The numerical results show that the total optical path length of the thin film Si solar cell covered with the HP glass increases from 2? to 4?. These results are basically consistent with the experimental results. Project supported by the National High-Tech Research and Development Program of China (Grant No. 2011AA050518).

  6. Growth, etching, and stability of sputtered ZnO:Al for thin-film silicon solar cells

    Owen, Jorj Ian

    2011-01-01

    Aluminum doped zinc oxide (ZnO:Al) can fulfill many requirements in thin film solar cells, acting as (1) a transparent contact through which the incident light is transmitted, (2) part of the back reflector, and (3) a source of light scattering. Magnetron sputtered ZnO:Al thin films are highly transparent, conductive, and are typically texturized by post deposition etching in a dilute hydrochloric acid (HCl) solution to achieve light scattering. The ZnO:Al thin film electronic and optical pro...

  7. Comparison and optimization of randomly textured surfaces in thin-film solar cells.

    Rockstuhl, C; Fahr, S; Bittkau, K; Beckers, T; Carius, R; Haug, F-J; Sderstrm, T; Ballif, C; Lederer, F

    2010-09-13

    Using rigorous diffraction theory we investigate the scattering properties of various random textures currently used for photon management in thin-film solar cells. We relate the haze and the angularly resolved scattering function of these cells to the enhancement of light absorption. A simple criterion is derived that provides an explanation why certain textures operate more beneficially than others. Using this criterion we propose a generic surface profile that outperforms the available substrates. This work facilitates the understanding of the effect of randomly textured surfaces and provides guidelines towards their optimization. PMID:21165064

  8. Beyond optical enhancement due to embedded metal nanoparticles in thin-film solar cells

    Murthy Mopurisetty, Sundara; Bajaj, Mohit; Ganguly, Swaroop

    2016-03-01

    Metal nanoparticles (MNPs) inside the active layer of thin-film solar cells are considered promising for light trapping, but they have also engendered concerns over their adverse impact on transport properties. Contrary to expectations, coupled optical and electrical simulations indicate that a purely electrical effect due to MNPs might result in an enhancement of the cell performance in addition to the gain from optical (plasmonic) effects. This electrical enhancement strongly depends on the MNP/semiconductor barrier height. On the other hand, the anticipated degradation due to trap states and surface recombination at the MNP/semiconductor interface may in fact be negligible.

  9. Effects of RF power and pressure on performance of HF-PECVD silicon thin-film solar cells

    High-frequency plasma-enhanced chemical vapor deposition (HF-PECVD) is a widely applicable method of deposition over a large area at a high rate for fabricating silicon thin-film solar cells. This investigation presents the properties of hydrogenated amorphous silicon (a-Si:H) films and the preparation of highly-efficient p-i-n solar cells using an RF (27.1 MHz) excitation frequency. The influence of the power (10-40 W) and pressure (20-50 Pa) used during the deposition of absorber layers in p-i-n solar cells on the properties and mechanism of growth of the a-Si:H thin films and the solar cells is studied. The a-Si:H thin films prepared under various deposition conditions have widely varying deposition rates, optical-electronic properties and microstructures. When the deposition parameters were optimized, amorphous silicon-based thin-film silicon solar cells with efficiency of 7.6% were fabricated by HF-PECVD. These results are very encouraging for the future fabrication of highly-efficient thin-film solar cells by HF-PECVD.

  10. A study of ZnO:B films for thin film silicon solar cells

    Highlights: ? ZnO:B films with different thicknesses were prepared with LPCVD technique. ? The thicker ZnO:B back electrodes lead to higher FF but slightly lower Jsc. ? Back polyvinyl butyral (PVB) foils improves the utilization of incident light in solar cells. ? The thicker ZnO:B front electrode films result in high Jsc but lower FF. - Abstract: Boron doped zinc oxide (ZnO:B) films with different thicknesses were prepared with low pressure chemical vapor deposition (LPCVD) technique and implemented in thin film silicon solar cells as front and back electrodes. It is found that thick back ZnO:B film electrode in thin film silicon solar cells leads to a high fill factors (FF), which is attributed to an improvement of the electrical properties of the thick ZnO:B films, and in the meanwhile a slightly low short circuit currents (Jsc) due to a high light absorption in the thick back ZnO:B films. Differently, the thicker front ZnO:B film electrodes result in a high Jsc but a low FF of solar cells compared to the thinner ones. The low FF of the solar cells may be caused by the local shunt originated from the pinholes or by the cracks (zones of non-dense material) formed in particular in microcrystalline silicon materials deposited on rough front ZnO:B films. As to the high Jsc, it is expected to be due to a good light trapping effect inside solar cells grown on rough front ZnO:B films. Moreover, the application of high reflective polyvinyl butyral (PVB) foils effectively enhances the utilization of incident light in solar cells. By optimizing deposition process of the ZnO:B films, high efficiencies of 8.8% and 10% for single junction thin film amorphous silicon solar cells (a-Si:H, intrinsic layer thickness < 200 nm) and amorphous/microcrystalline silicon tandem solar cells (a-Si:H/?c-Si:H, intrinsic amorphous silicon layer thickness < 220 nm), respectively, are achieved.

  11. Back contact buffer layer for thin-film solar cells

    Compaan, Alvin D.; Plotnikov, Victor V.

    2014-09-09

    A photovoltaic cell structure is disclosed that includes a buffer/passivation layer at a CdTe/Back contact interface. The buffer/passivation layer is formed from the same material that forms the n-type semiconductor active layer. In one embodiment, the buffer layer and the n-type semiconductor active layer are formed from cadmium sulfide (CdS). A method of forming a photovoltaic cell includes the step of forming the semiconductor active layers and the buffer/passivation layer within the same deposition chamber and using the same material source.

  12. Defect annealing processes for polycrystalline silicon thin-film solar cells

    Steffens, S., E-mail: simon.steffens@helmholtz-berlin.de [Helmholtz-Zentrum Berlin, Berlin (Germany); Becker, C. [Helmholtz-Zentrum Berlin, Berlin (Germany); Zollondz, J.-H., E-mail: hzollondz@masdarpv.com [CSG Solar AG, Thalheim (Germany); Chowdhury, A.; Slaoui, A. [LInstitut dlectronique du Solide et des Systmes, Strasbourg (France); Lindekugel, S. [Fraunhofer-Institut fr Solare Energiesysteme, Freiburg (Germany); Schubert, U.; Evans, R. [Suntech R and D Australia Pty Ltd, Sydney (Australia); Rech, B. [Helmholtz-Zentrum Berlin, Berlin (Germany)

    2013-05-15

    Highlights: ? Defect annealing processes were applied to polycrystalline silicon thin films. ? Conventional rapid thermal annealing was compared to novel annealing processes using a laser system and a zone-melting recrystallization setup. ? The open circuit voltages could be enhanced from below 170 mV up to 482 mV. ? Increase in Sun's-V{sub OC} values with decrease in FWHM of the TO Raman phonon of crystalline silicon. ? Solar cells were fabricated for IV-measurements: Best solar cell efficiency of 6.7%. -- Abstract: A variety of defect healing methods was analyzed for optimization of polycrystalline silicon (poly-Si) thin-film solar cells on glass. The films were fabricated by solid phase crystallization of amorphous silicon deposited either by plasma enhanced chemical vapor deposition (PECVD) or by electron-beam evaporation (EBE). Three different rapid thermal processing (RTP) set-ups were compared: A conventional rapid thermal annealing oven, a dual wavelength laser annealing system and a movable two sided halogen lamp oven. The two latter processes utilize focused energy input for reducing the thermal load introduced into the glass substrates and thus lead to less deformation and impurity diffusion. Analysis of the structural and electrical properties of the poly-Si thin films was performed by Suns-V{sub OC} measurements and Raman spectroscopy. 1 cm{sup 2} cells were prepared for a selection of samples and characterized by IV-measurements. The poly-Si material quality could be extremely enhanced, resulting in increase of the open circuit voltages from about 100 mV (EBE) and 170 mV (PECVD) in the untreated case up to 480 mV after processing.

  13. Incorporation of Cu in Cu(In,Ga)Se2-based thin-film solar cells

    We have fabricated Cu(In,Ga)Se2 (CIGS)-based thin-film solar cells by using a cluster-type deposition system. The system is composed of a DC sputter for the Mo back electrode, a co-evaporator for the CIGS absorption layer, and a RF sputter for the ZnO and the transparent-conductive-oxide (TCO) window layers. The deposition of the CdS buffer layer was performed separately. Two solar cells with an effective area of 0.47 cm2 were fabricated using different processes. One cell, which was prepared with a 1-step process, had a larger atomic concentration of In-Ga than of Cu in the absorption layer and showed a conversion efficiency of 11.1%. The other prepared with a 3-step process had nearly the same In-Ga and Cu concentrations and showed a conversion efficiency of 15.5%. We discuss the incorporation of Cu in the two types of thin-film solar cells.

  14. Broadband absorption enhancement in plasmonic thin-film solar cells with grating surface

    Liu, Li; Huo, Yiping; Zhao, Kaijun; Zhao, Ting; Li, Yuan

    2015-10-01

    The plasmonic thin-film solar cells with grating surface is structured and simulated by Comsol Multiphysics software using finite element method. The absorption efficiency of solar cells has been systemically studied by considering structure characteristic parameters. The absorption of grating surface cell is much broader and stronger than that of smooth surface on a-Si at the wavelength from 400 to 700 nm. The value of total absorption efficiency (TAE) increases from 47% to 69.3%. The embedded Ag nanoparticle array contributes to the improvement of the absorption of a-Si at longer wavelength range. The localized surface plasmon resonance is induced by Ag nanoparticles, and so that the TAE is increased to 75.1% when the radius of nanoparticle is 60 nm at the bottom of a-Si with periodic width 200 nm. The grating surface always plays a role to suppress light scattering from the active region, so more light can be absorbed again by a-Si in the infrared-region. Therefore, the results have significance in providing a theoretical foundation for the applications of thin-film solar cell.

  15. Multi-Material Front Contact for 19% Thin Film Solar Cells

    Joop van Deelen

    2016-02-01

    Full Text Available The trade-off between transmittance and conductivity of the front contact material poses a bottleneck for thin film solar panels. Normally, the front contact material is a metal oxide and the optimal cell configuration and panel efficiency were determined for various band gap materials, representing Cu(In,GaSe2 (CIGS, CdTe and high band gap perovskites. Supplementing the metal oxide with a metallic copper grid improves the performance of the front contact and aims to increase the efficiency. Various front contact designs with and without a metallic finger grid were calculated with a variation of the transparent conductive oxide (TCO sheet resistance, scribing area, cell length, and finger dimensions. In addition, the contact resistance and illumination power were also assessed and the optimal thin film solar panel design was determined. Adding a metallic finger grid on a TCO gives a higher solar cell efficiency and this also enables longer cell lengths. However, contact resistance between the metal and the TCO material can reduce the efficiency benefit somewhat.

  16. Enhanced light trapping with double-groove grating in thin-film amorphous silicon solar cells

    Wu, Jun

    2016-05-01

    A design to enhance light absorption in thin-film amorphous silicon (a-Si) solar cells is proposed. It is achieved by patterning a double-groove grating with waveguide layer as the absorbing layer and coating a double-groove grating anti-reflective layer in the front window of the cell. The broadband absorption under normal incidence can be achieved for both TE and TM polarizations. It is shown that the averaged integrated absorptions have very large angle independence for the optimized solar cell. An qualitative understanding of such broadband enhanced absorption effect, which is attributed to the guided mode resonance, is presented. The conclusions can be exploited to guide the design of solar cells based on a grating structure.

  17. Progress in Thin Film Solar Cells Based on Cu2ZnSnS4

    Hongxia Wang

    2011-01-01

    The research in thin film solar cells has been dominated by light absorber materials based on CdTe and Cu(In,Ga)Se2 (CIGS) in the last several decades. The concerns of environment impact of cadmium and the limited availability of indium in those materials have driven the research towards developing new substitute light absorbers made from earth abundant, environment benign materials. Cu2ZnSnS4 (CZTS) semiconductor material has emerged as one of the most promising candidates for this aim and h...

  18. Large CZTS Nanoparticles Synthesized by Hot-Injection for Thin Film Solar Cells.

    Engberg, Sara Lena Josefin; Lam, Yeng Ming; Schou, Jrgen

    2015-01-01

    The kesterite material, Cu2ZnSn(SxSe1-x)4 (CZTS), shows great promise as the absorber layer for future thin film solar cells. Solution processing allows for comparatively fast and inexpensive fabrication, and holds the record efficiency in the kesterite family. However, for nanoparticle (NP) solution processing to be a feasible fabrication route, the amount of carbon in the film has to be limited. In our work, we try to limit the organic material in the film by synthesizing larger NPs. Larger...

  19. Surpassing the classical light-trapping limit in thin film solar cells

    Munday, Jeremy; Callahan, Dennis; Atwater, Harry

    2011-03-01

    We describe a methodology for designing thin film solar cells that have light-trapping intensity and absorption enhancements that exceed the classical, ergodic light-trapping limit. From thermodynamic arguments, Yablonovitch and Cody determined the maximum absorption enhancement in the ray optics limit for a bulk material to be 4n2 , where n is the index of refraction of the absorbing layer. Stuart and Hall expanded this approach to study a simple waveguide structure; however, for the waveguide structures they considered, the maximum absorption enhancement was <4n^ 2 . Usingacombinationofanalyticalandnumericalmethods , wedescribewhythesestructuresdonotsurpasstheergodiclimitandshowhowtodesignstructuresthatcan . Wepresenthereaphysicalinterpretationintermsofthewaveguidedispersionrelationsandopticaldensityofstates . Wefurtherdescribethenecessarycriteriaforsurpassingtheclassicallimitandprovideexamplesofwaveguidestructureswithabsorptionenhancementsinexcessof 4n2 .

  20. Enhanced light absorption in thin film silicon solar cells with Fourier-series based periodic nanostructures.

    Guo, Xiaowei; Wang, Dashuai; Liu, Bang; Li, Shaorong; Sheng, Xing

    2016-01-25

    We proposed a Fourier-series based periodic nanostructure(FSPN) for light trapping in thin film silicon solar cells. By globally optimizing the Fourier coefficients across entire silicon absorption spectrum, we obtained a FSPN structure with short circuit current density greater than 24 mA/cm2 for a 1?m real silicon absorption layer. The spectral analysis shows at normal incidence the FSPN exhibits a collection effect of periodic gratings and performs over 84.6% better than random texture. The angular analysis shows that the FSPN outperforms grating and random textures within 70 . PMID:26832592

  1. Microcrystalline silicon absorber layers prepared at high deposition rates for thin-film tandem solar cells

    Michard S.; Balmes V.; Meier M.; Lambertz A.; Merdzhanova T.; Finger F.

    2013-01-01

    We have investigated high deposition rate processes for the fabrication of thin-film silicon tandem solar cells. Microcrystalline silicon absorber layers were prepared under high pressure depletion conditions at an excitation frequency of 81.36 MHz. The deposition rate was varied in the range of 0.2 nm/s to 3.2 nm/s by varying the deposition pressure and deposition power for given electrode spacings. The silane-to-hydrogen process gas mixture was adjusted in each case to prepare optimum phase...

  2. In Situ Measuring System Designed for Improvement of Poly-Si Thin Film Solar Cells

    Pikna, Peter; Fejfar, Antonín; Ledinský, Martin; Vetushka, Aliaksi; Kočka, Jan; Benda, V.

    Honolulu, 2011. [The Fourth International Forum on Multidisciplinary Education and Research for Energy Science. 17.12.2011-21.12. 2011, Honolulu, Hawaii] R&D Projects: GA MŠk(CZ) LC06040; GA AV ČR KAN400100701; GA MŠk LC510 EU Projects: European Commission(XE) 240826 - PolySiMode Institutional research plan: CEZ:AV0Z10100521 Keywords : polycrystalline silicon * thin film solar cells * water vapor passivation Subject RIV: BM - Solid Matter Physics ; Magnetism

  3. Aluminium induced texturing of glass substrates with improved light management for thin film solar cells

    Lluscà, M. (Marta); Urbain, Félix; Smirnov, Vladimir; Antony, Aldrin; Andreu i Batallé, Jordi; Bertomeu i Balagueró, Joan

    2016-01-01

    Aluminium induced texturing (AIT) method has been used to texture glass substrates to enhance photon absorption in microcrystalline thin film Si solar cells. In this process, a thin Al film is deposited on a glass substrate and a non-uniform redox reaction between the glass and the Al film occurs when they are annealed at high temperature. After etching the reaction products, the resultant glass surface presents a uniform and rough morphology. In this work, three different textures (­σrms ~85...

  4. Modeling and optimization of white paint back reflectors for thin-film silicon solar cells

    Lipovšek, Benjamin; Krč, Janez; Isabella, Olindo; Zeman, Miro; Topič, Marko

    2010-11-01

    Diffusive dielectric materials such as white paint have been demonstrated as effective back reflectors in the photovoltaic technology. In this work, a one-dimensional (1D) optical modeling approach for simulation of white paint films is developed and implemented in a 1D optical simulator for thin-film solar cells. The parameters of white paint, such as the paint film thickness, the pigment volume concentration (PVC), and the pigment/binder refractive index ratio (RIR), are examined and optimized to achieve the required optical properties for back reflector application. The simulation trends indicate that white paint back reflectors with sufficient film thickness and higher PVC and RIR values exhibit improved reflectivity characteristics which results in an increased long-wavelength quantum efficiency of thin-film silicon solar cells. The simulation results based on the 1D model agree very well with the experimental data obtained from reflectance measurements of various white paint compositions and quantum efficiency measurements of amorphous silicon solar cells with white paint back reflectors.

  5. Thin film polycrystalline silicon: Promise and problems in displays and solar cells

    Fonash, S.J. [Pennsylvania State Univ., University Park, PA (United States)

    1995-08-01

    Thin film polycrystalline Si (poly-Si) with its carrier mobilities, potentially good stability, low intragrain defect density, compatibility with silicon processing, and ease of doping activation is an interesting material for {open_quotes}macroelectronics{close_quotes} applications such as TFTs for displays and solar cells. The poly-Si films needed for these applications can be ultra-thin-in the 500{Angstrom} to 1000{Angstrom} thickness range for flat panel display TFTs and in the 4{mu}m to 10{mu}m thickness range for solar cells. Because the films needed for these microelectronics applications can be so thin, an effective approach to producing the films is that of crystallizing a-Si precursor material. Unlike cast materials, poly-Si films made this way can be produced using low temperature processing. Unlike deposited poly-Si films, these crystallized poly-Si films can have grain widths that are much larger than the film thickness and almost atomically smooth surfaces. This thin film poly-Si crystallized from a-Si precursor films, and its promise and problems for TFTs and solar cells, is the focus of this discussion.

  6. Positive ion irradiation of CdS/Cu2S thin film solar cells

    The effect of positive ion bombardment on unencapsulated CdS/Cu2S thin film solar cells has been studied using monoenergetic positive ions (of 1H, 4He, 16O, 32S, 35Cl, 40Ar, 63Cu, 84Kr, 112Cd or 132Xe) with energies in the range 10 to 50 keV. The current-voltage characteristics of the cells have been analysed in terms of a five parameter model. The cell degradations produced by radiation damage have been shown to be dependent on the range of the incident particle. A reduction of the short circuit current was shown to result from damage to the cuprous sulphide layer of the cell whereas damage to the junction region was found to give rise to a reduction in the open circuit voltage. Annealing effects on radiation-degraded unencapsulated solar cells have been studied and the fractional recoveries of the cell parameters have been compared. (author)

  7. Periodic anti-ring back reflectors for hydrogenated amorphous silicon thin-film solar cells.

    Chen, Po-Yuan; Hsiao, Hui-Hsin; Ho, Chung-I; Ho, Chi-Chih; Lee, Wei-Li; Chang, Hung-Chun; Lee, Si-Chen; Chen, Jian-Zhang; Cheng, I-Chun

    2014-06-30

    Large and periodic anti-ring arrays are fabricated by using a monolayer of polymer/nanosphere hybrid technique and applied as back reflectors in substrate-type hydrogenated amorphous silicon (a-Si:H) thin-film solar cells. The structure of each anti-ring comprises a nanodome centered inside a nanohole. The excitation of Bloch wave surface plasmon polaritons is observed in the Ag-coated anti-ring arrays. The nanodomes of the anti-ring arrays turn out to enhance large-angle light scattering and increase the effective optical path in the solar cell. The resulting efficiency of an ultrathin a-Si:H (thickness: 150 nm) solar cell is enhanced by 39% compared to that with a flat back reflector and by 13% compared to that with a nanohole back reflector. PMID:24978075

  8. Improved homogeneity of microcrystalline absorber layer in thin-film silicon tandem solar cells

    Smirnov, Vlad [IEF-5 Photovoltaik, Forschungszentrum Juelich GmbH, Leo-Brandt Str., D-52425 Juelich (Germany)], E-mail: v.smirnov@fz-juelich.de; Das, Chandan; Melle, Thomas; Lambertz, Andreas; Huelsbeck, Markus; Carius, Reinhard; Finger, Friedhelm [IEF-5 Photovoltaik, Forschungszentrum Juelich GmbH, Leo-Brandt Str., D-52425 Juelich (Germany)

    2009-03-15

    A study of the effects of microcrystalline silicon i-layer modification near p/i interface in tandem configuration silicon thin film solar cells is presented. The structural properties of the absorber layers were investigated by Raman spectroscopy at different stages of growth. The results indicate the possibility of improving both the nucleation process and the film homogeneity in the direction of growth, without specific re-optimization of the p-layer, transferred from a single-junction microcrystalline silicon cell. Structural modifications of the i-layer have been correlated with performance of tandem solar cells, leading to improvements in the bottom cell current J{sub sc} (up to 11.4 mA/cm{sup 2}) and initial tandem-cell conversion efficiency (up to 11.3%)

  9. Improved homogeneity of microcrystalline absorber layer in thin-film silicon tandem solar cells

    A study of the effects of microcrystalline silicon i-layer modification near p/i interface in tandem configuration silicon thin film solar cells is presented. The structural properties of the absorber layers were investigated by Raman spectroscopy at different stages of growth. The results indicate the possibility of improving both the nucleation process and the film homogeneity in the direction of growth, without specific re-optimization of the p-layer, transferred from a single-junction microcrystalline silicon cell. Structural modifications of the i-layer have been correlated with performance of tandem solar cells, leading to improvements in the bottom cell current Jsc (up to 11.4 mA/cm2) and initial tandem-cell conversion efficiency (up to 11.3%).

  10. Novel concepts for low-cost and high-efficient thin film solar cells

    Gómez, D.; Menéndez, A.; Sánchez, P.; Martínez, A.; Andrés, L. J.; Menéndez, M. F.; Campos, N.; García, A.; Sánchez, B.

    2011-09-01

    This work presents the activities carried out at ITMA Materials Technology related to the building integration of thin film (TF) photovoltaics (PV). Three different approaches have been developed in order to achieve high efficient solar cells at low manufacturing costs: (i) a new route for manufacturing monolithical silicon based thin film solar cells on building materials, (ii) the use of metallic nanoparticles for light trapping (plasmonic effects and light scattering) and (iii) the luminescent sol-gel coating on glass for solar concentration. In the first case, amorphous silicon modules (single junction) have been successfully manufactured at lab scale on steel and commercial ceramic substrates with efficiencies of 5.4% and 4.0%, respectively. Promising initial attempts have been also made in ethylene tetrafluoroethylene (ETFE), a polymer with high potential in textile architecture. In a similar way, the development of nanotechnology based coatings (metallic nanoparticles and luminescent materials) represent the most innovative part of the work and some preliminary results are showed.

  11. Novel p-Type Conductive Semiconductor Nanocrystalline Film as the Back Electrode for High-Performance Thin Film Solar Cells.

    Zhang, Ming-Jian; Lin, Qinxian; Yang, Xiaoyang; Mei, Zongwei; Liang, Jun; Lin, Yuan; Pan, Feng

    2016-02-10

    Thin film solar cells, due to the low cost, high efficiency, long-term stability, and consumer applications, have been widely applied for harvesting green energy. All of these thin film solar cells generally adopt various metal thin films as the back electrode, like Mo, Au, Ni, Ag, Al, graphite, and so forth. When they contact with p-type layer, it always produces a Schottky contact with a high contact potential barrier, which greatly affects the cell performance. In this work, we report for the first time to find an appropriate p-type conductive semiconductor film, digenite Cu9S5 nanocrystalline film, as the back electrode for CdTe solar cells as the model device. Its low sheet resistance (16.6 ?/sq) could compare to that of the commercial TCO films (6-30 ?/sq), like FTO, ITO, and AZO. Different from the traditonal metal back electrode, it produces a successive gradient-doping region by the controllable Cu diffusion, which greatly reduces the contact potential barrier. Remarkably, it achieved a comparable power conversion efficiency (PCE, 11.3%) with the traditional metal back electrode (Cu/Au thin films, 11.4%) in CdTe cells and a higher PCE (13.8%) with the help of the Au assistant film. We believe it could also act as the back electrode for other thin film solar cells (?-Si, CuInS2, CIGSe, CZTS, etc.), for their performance improvement. PMID:26736028

  12. Band alignment measurements at heterojunction interfaces in layered thin film solar cells & thermoelectrics

    Fang, Fang

    2011-12-01

    Public awareness of the increasing energy crisis and the related serious environmental concerns has led to a significantly growing demand for alternative clean and renewable energy resources. Thin film are widely applied in multiple renewable energy devices owing to the reduced amount of raw materials and increase flexibility of choosing from low-cost candidates, which translates directly into reduced capital cost. This is a key driving force to make renewable technology competitive in the energy market. This thesis is focused on the measurement of energy level alignments at interfaces of thin film structures for renewable energy applications. There are two primary foci: II -VI semiconductor ZnSe/ZnTe thin film solar cells and Bi2Te3/Sb2Te3 thin film structures for thermoelectric applications. In both cases, the electronic structure and energy band alignment at interfaces usually controls the carrier transport behavior and determines the quality of the device. High-resolution photoemission spectroscopy (lab-based XPS & synchrotron-based UPS) was used to investigate the chemical and electronic properties of epitaxial Bi2Te3 and Sb2Te3 thin films, in order to validate the anticipated band alignment at interfaces in Bi 2Te3/Sb2Te3 superlattices as one favoring electron-transmission. A simple, thorough two-step treatment of a chemical etching in dilute hydrochloric acid solution and a subsequent annealing at ˜150°C under ultra-high vacuum environment is established to remove the surface oxides completely. It is an essential step to ensure the measurements on electronic states are acquired on stoichimetric, oxide-free clean surface of Bi 2Te3 and Sb2Te3 films. The direct measurement of valence band offsets (VBO) at a real Sb 2Te3/Bi2Te3 interface is designed based on the Kraut model; a special stacking film structure is prepared intentionally: sufficiently thin Sb2Te3 film on top of Bi2Te 3 that photoelectrons from both of them are collected simultaneously. From a combination of core levels and valence band ultraviolet photoemission spectra of the bulk materials as well as the heterojunction (Sb2Te 3/Bi2Te3), the VBO at p-type Sb2Te 3 and n-type Bi2Te3 is determined as 0.04 +/- 0.10 eV. Such a small energy offset is within the same magnitude of the thermal energy of kT, at room temperature. The motivation for the II-VI ZnTe-based thin film solar cell derives from the need to identify and overcome performance-limiting properties related to the processing of film deposition using close space sublimation (CSS). Chemical and electronic properties of the CSS grown ZnTe/ZnSe films were studied in x-ray diffraction, scanning electron microscopy and photoemission spectroscopy. Specifically, Se oxide was observed on the ZnSe surface, the removal of this oxide generated apparent offsets in the valence band and hence the alignment at the heterojunction energy diagram. Processing steps to mitigate oxidation yielded the best cells. Film structure was studied on the dependence of growth time; physical film damage is found during the initial stages when depositing ZnTe on a grown ZnSe film. Preliminary studies of films grown by evaporation and their characterizations are presented at last. In this thesis, a better understanding of the electronic structure at interfaces is built in two different thin film devices, and the resulting band energy diagram of the corresponding devices offered effective feedback in materials and device.The problem of energy equilibrium in the human body has received a great deal.

  13. Recrystallized thin-film silicon solar cell on graphite substrate with laser single side contact and hydrogen passivation

    Li Da

    2015-01-01

    Full Text Available Laser single side contact formation (LSSC and the hydrogen passivation process are studied and developed for crystalline silicon thin film (CSiTF solar cells on graphite substrates. The results demonstrate that these two methods can improve cell performance by increasing the open circuit voltage and fill factor. In comparison with our previous work, we have achieved an increase of 3.4% absolute cell efficiency for a 40 μm thick 4 cm2 aperture area silicon thin film solar cell on graphite substrate. Current density-voltage (J-V measurement, quantum efficiency (QE and light beam induced current (LBiC are used as characterization methods.

  14. Crystalline silicon for thin film solar cells. Final report; Kristallines Silizium fuer Duennschichtsolarzellen. Schlussbericht

    Wagner, H.

    2001-07-01

    Thin film solar cells based on silicon are of great interest for cost-effective conversion of solar energy into electric power. In order to reach this goal, intensive research is still necessary, pointing, e.g., to a further enhancement of the conversion efficiency, an improvement of stability and a reduction of the production time. Aim of the project work was the achievement of knowledge on microcrystalline silicon and its application in thin film solar cells by means of a broad research and development program. Material research focused on growth processes of the microcrystalline material, the incorporation and stability of hydrogen, the electronic transport and defects. In particular the transition from amorphous to microcrystalline material which is obtained for the present deposition methods by minor variations of the deposition parameters as well as the enhancement of the deposition rate were intensively studies. Another focus of research aimed toward the development and improvement of zinc oxide films which are of central importance for this type of solar cells for the application as transparent contacts. A comprehensive understanding was achieved. The films were incorporated in thin film solar cells and with conversion efficiencies >8% for single cells (at relatively high deposition rate) and 10% (stable) for tandem cells with amorphous silicon, top values were achieved by international standards. The project achievements serve as a base for a further development of this type of solar cell and for the transfer of this technology to industry. (orig.) [German] Duennschichtsolarzellen auf der Basis von Silizium sind von grossem Interesse fuer eine kostenguenstige Umwandlung von Sonnenenergie in elektrischen Strom. Um dieses Ziel zu erreichen, ist jedoch noch intensive Forschung, u.a. zur weiteren Steigerung des Wirkungsgrades, zur Verbesserung der Stabilitaet und zur Verkuerzung des Produktionsprozesses erforderlich. Ziel der Projektarbeiten war, durch ein breit angelegtes Forschungs- und Entwicklungsprogramm Kenntnisse ueber mikrokristallines Silizium und dessen Einsatzmoeglichkeit in Duennschichtsolarzellen zu gewinnen. Im Rahmen der Materialforschungzustanden Wachstumsprozesse von mirkrokristallinem Material, der Einbau und die Stabilitaet von Wasserstoff, der elektronische Transport und Defekte im Vordergrund. Insbesondere der Uebergang amorph-mikrokristallin, der bei den vorliegenden Depositionsmethoden durch geringfuegige Veraenderungen der Depositionsparameter erreicht werden kann, sowie eine Erhoehung der Depositionsrate wurden intensiv untersucht. Weiterhin wurden an der Entwicklung und Optimierung von Zinkoxidschichten gearbeitet, die fuer diesen Typ von Solarzellen als transparente Kontaktschichten von zentraler Bedeutung sind. Ein umfassendes Verstaendnis wurde erzielt. Die Schichten wurden in Duennschichtsolarzellen eingebaut und mit Wirkungsgraden >8% fuer Einzelzellen (bei relativ hohen Depositionsraten) und 10% (stabil) fuer Tandemsolarzellen mit amorphem Silizium wurden Spitzenwerte (im internationalen Vergleich) erreicht. Die Projektergebnisse dienen als Basis fuer die Weiterentwicklung dieses Solarzellentyps und fuer einen Transfer der Technologie in die Industrie. (orig.)

  15. Effect of Gaussian doping profile on the performance of a thin film polycrystalline solar cell

    Ouali A.

    2012-06-01

    Full Text Available A two-dimensional (2D analytical model based on the Green’s function method is applied to an n+-p thin film polycrystalline solar cell that allows us to calculate the conversion efficiency. This model considers the effective Gaussian doping profile in the p region in order to improve cell efficiency. The dependence of mobility and lifetime on grain doping is also investigated. This model is implemented through a simulation program in order to optimize conversion efficiency while varying thickness and doping profile in the base region of the cell. Compared with n+-p standard structure, our proposed structure shows a 43% improvement in conversion efficiency for a polycrystalline solar cell.

  16. ZnO transparent conductive oxide for thin film silicon solar cells

    Söderström, T.; Dominé, D.; Feltrin, A.; Despeisse, M.; Meillaud, F.; Bugnon, G.; Boccard, M.; Cuony, P.; Haug, F.-J.; Faÿ, S.; Nicolay, S.; Ballif, C.

    2010-03-01

    There is general agreement that the future production of electric energy has to be renewable and sustainable in the long term. Photovoltaic (PV) is booming with more than 7GW produced in 2008 and will therefore play an important role in the future electricity supply mix. Currently, crystalline silicon (c-Si) dominates the market with a share of about 90%. Reducing the cost per watt peak and energy pay back time of PV was the major concern of the last decade and remains the main challenge today. For that, thin film silicon solar cells has a strong potential because it allies the strength of c-Si (i.e. durability, abundancy, non toxicity) together with reduced material usage, lower temperature processes and monolithic interconnection. One of the technological key points is the transparent conductive oxide (TCO) used for front contact, barrier layer or intermediate reflector. In this paper, we report on the versatility of ZnO grown by low pressure chemical vapor deposition (ZnO LP-CVD) and its application in thin film silicon solar cells. In particular, we focus on the transparency, the morphology of the textured surface and its effects on the light in-coupling for micromorph tandem cells in both the substrate (n-i-p) and superstrate (p-i-n) configurations. The stabilized efficiencies achieved in Neuchâtel are 11.2% and 9.8% for p-i-n (without ARC) and n-i-p (plastic substrate), respectively.

  17. Enhancing the absorption capabilities of thin-film solar cells using sandwiched light trapping structures.

    Abdellatif, S; Kirah, K; Ghannam, R; Khalil, A S G; Anis, W

    2015-06-10

    A novel structure for thin-film solar cells is simulated with the purpose of maximizing the absorption of light in the active layer and of reducing the parasitic absorption in other layers. In the proposed structure, the active layer is formed from an amorphous silicon thin film sandwiched between silicon nanowires from above and photonic crystal structures from below. The upper electrical contact consists of an indium tin oxide layer, which serves also as an antireflection coating. A metal backreflector works additionally as the other contact. The simulation was done using a new reliable, efficient and generic optoelectronic approach. The suggested multiscale simulation model integrates the finite-difference time-domain algorithm used in solving Maxwell's equation in three dimensions with a commercial simulation platform based on the finite element method for carrier transport modeling. The absorption profile, the external quantum efficient, and the power conversion efficiency of the suggested solar cell are calculated. A noticeable enhancement is found in all the characteristics of the novel structure with an estimated 32% increase in the total conversion efficiency over a cell without any light trapping mechanisms. PMID:26192857

  18. Light Trapping in Thin Film Silicon Solar Cells on Plastic Substrates

    de Jong, M. M.

    2013-01-01

    In the search for sustainable energy sources, solar energy can fulfil a large part of the growing demand. The biggest threshold for large-scale solar energy harvesting is the solar panel price. For drastic cost reductions, roll-to-roll fabrication of thin film silicon solar cells using plastic substrates can be a solution. In this thesis, we investigate the possibilities of depositing thin film solar cells directly onto cheap plastic substrates. Micro-textured glass and sheets, which have a wide range of applications, such as in green house, lighting etc, are applied in these solar cells for light trapping. Thin silicon films can be produced by decomposing silane gas, using a plasma process. In these types of processes, the temperature of the growing surface has a large influence on the quality of the grown films. Because plastic substrates limit the maximum tolerable substrate temperature, new methods have to be developed to produce device-grade silicon layers. At low temperature, polysilanes can form in the plasma, eventually forming dust particles, which can deteriorate device performance. By studying the spatially resolved optical emission from the plasma between the electrodes, we can identify whether we have a dusty plasma. Furthermore, we found an explanation for the temperature dependence of dust formation; Monitoring the formation of polysilanes as a function of temperature using a mass-spectrometer, we observed that the polymerization rate is indeed influenced by the substrate temperature. For solar cell substrate material, our choice was polycarbonate (PC), because of its low cost, its excellent transparency and its relatively high glass transition temperature of 130-140°C. At 130°C we searched for deposition recipes for device quality silicon, using a very high frequency plasma enhanced chemical deposition process. By diluting the feedstock silane with hydrogen gas, the silicon quality can be improved for amorphous silicon (a-Si), until we reach the nanocrystalline silicon (nc-Si) regime. In the nc-Si regime, the crystalline fraction can be further controlled by changing the power input into the plasma. With these layers, a-Si thin film solar cells were fabricated, on glass and PC substrates. The adverse effect of the low temperature growth on the photoactive material is further mitigated by using thinner silicon layers, which can deliver a good current only with an adequate light trapping technique. We have simulated and experimentally tested three light trapping techniques, using embossed structures in PC substrates and random structures on glass: regular pyramid structures larger than the wavelength of light (micropyramids), regular pyramid structures comparable to the wavelength of light (nanopyramids) and random nano-textures (Asahi U-type). The use of nanostructured polycarbonate substrates results in initial conversion efficiencies of 7.4%, compared to 7.6% for cells deposited under identical conditions on Asahi U-type glass. The potential of manufacturing thin film solar cells at processing temperatures lower than 130oC is further illustrated by obtained results on texture-etched aluminium doped zinc-oxide (ZnO:Al) on glass: we achieved 6.9% for nc-Si cells using a very thin absorber layer of only 750 nm, and by combining a-Si and nc-Si cells in tandem solar cells we reached an initial conversion efficiency of 9.5%.

  19. Morphology dependent dye-sensitized solar cell properties of nanocrystalline zinc oxide thin films

    Sharma, S.K., E-mail: sanjeevlrs732000@yahoo.co.in [Department of Information and Communication, Cheju Halla College, Jeju City 690 708 (Korea, Republic of); Inamdar, A.I.; Im, Hyunsik [Department of Semiconductor Science, Dongguk University, Seoul 100 715 (Korea, Republic of); Kim, B.G. [Department of Information and Communication, Cheju Halla College, Jeju City 690 708 (Korea, Republic of); Patil, P.S. [Thin Film Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004 (India)

    2011-02-03

    Research highlights: > Nano-crystalline zinc oxide thin films were electrosynthesized from an aqueous zinc acetate [Zn(CH{sub 3}COO){sub 2}.2H{sub 2}O] solution onto FTO coated conducting glass substrates using two different electrochemical routes, namely (i) without an organic surfactant and (ii) with an organic surfactant, viz. PVA (poly-vinyl alcohol) or SDS (sodium dodecyl sulfate). > The reproducibility of the catalytic activity of the SDS and PVA surfactants in the modification of the morphologies was observed. > Vertically aligned nest-like and compact structures were observed from the SDS and PVA mediated films, respectively, while the grain size in the ZnO thin films without an organic surfactant was observed to be {approx}150 nm. > The dye sensitized ZnO electrodes displayed excellent properties in the conversion process from light to electricity. The efficiencies of the surfactant mediated nanocrystalline ZnO thin films, viz. ZnO:SDS and ZnO:PVA, sensitized with ruthenium-II (N3) dye were observed to be 0.49% and 0.27%, respectively. - Abstract: Nano-crystalline zinc oxide thin films were electrosynthesized with an aqueous zinc acetate [Zn(CH{sub 3}COO){sub 2}.2H{sub 2}O] solution on to FTO coated glass substrates. Two different electrochemical baths were used, namely (i) without an organic surfactant and (ii) with an organic surfactant, viz. PVA (poly-vinyl alcohol) and SDS (sodium dodecyl sulfate). The organic surfactants played an important role in modifying the surface morphology, which influenced the size of the crystallites and dye-sensitized solar cell (DSSC) properties. The vertically aligned thin and compact hexagonal crystallites were observed with SDS mediated films, while the grain size in the films without an organic surfactant was observed to be {approx}150 nm. The conversion efficiencies of the ZnO:SDS:Dye and ZnO:PVA:Dye thin films were observed to be 0.49% and 0.27%, respectively.

  20. Morphology dependent dye-sensitized solar cell properties of nanocrystalline zinc oxide thin films

    Research highlights: → Nano-crystalline zinc oxide thin films were electrosynthesized from an aqueous zinc acetate [Zn(CH3COO)2.2H2O] solution onto FTO coated conducting glass substrates using two different electrochemical routes, namely (i) without an organic surfactant and (ii) with an organic surfactant, viz. PVA (poly-vinyl alcohol) or SDS (sodium dodecyl sulfate). → The reproducibility of the catalytic activity of the SDS and PVA surfactants in the modification of the morphologies was observed. → Vertically aligned nest-like and compact structures were observed from the SDS and PVA mediated films, respectively, while the grain size in the ZnO thin films without an organic surfactant was observed to be ∼150 nm. → The dye sensitized ZnO electrodes displayed excellent properties in the conversion process from light to electricity. The efficiencies of the surfactant mediated nanocrystalline ZnO thin films, viz. ZnO:SDS and ZnO:PVA, sensitized with ruthenium-II (N3) dye were observed to be 0.49% and 0.27%, respectively. - Abstract: Nano-crystalline zinc oxide thin films were electrosynthesized with an aqueous zinc acetate [Zn(CH3COO)2.2H2O] solution on to FTO coated glass substrates. Two different electrochemical baths were used, namely (i) without an organic surfactant and (ii) with an organic surfactant, viz. PVA (poly-vinyl alcohol) and SDS (sodium dodecyl sulfate). The organic surfactants played an important role in modifying the surface morphology, which influenced the size of the crystallites and dye-sensitized solar cell (DSSC) properties. The vertically aligned thin and compact hexagonal crystallites were observed with SDS mediated films, while the grain size in the films without an organic surfactant was observed to be ∼150 nm. The conversion efficiencies of the ZnO:SDS:Dye and ZnO:PVA:Dye thin films were observed to be 0.49% and 0.27%, respectively.

  1. Microcrystalline silicon carbide alloys prepared with HWCVD as highly transparent and conductive window layers for thin film solar cells

    Finger, F., E-mail: f.finger@fz-juelich.d [IEF-5 Photovoltaik, Forschungszentrum Juelich, 52425 Juelich (Germany); Astakhov, O.; Bronger, T.; Carius, R.; Chen, T.; Dasgupta, A.; Gordijn, A. [IEF-5 Photovoltaik, Forschungszentrum Juelich, 52425 Juelich (Germany); Houben, L. [IFF, Mikrostruktur, Forschungszentrum Juelich, 52425 Juelich (Germany); Huang, Y.; Klein, S. [IEF-5 Photovoltaik, Forschungszentrum Juelich, 52425 Juelich (Germany); Luysberg, M. [IFF, Mikrostruktur, Forschungszentrum Juelich, 52425 Juelich (Germany); Wang, H.; Xiao, L. [IEF-5 Photovoltaik, Forschungszentrum Juelich, 52425 Juelich (Germany)

    2009-04-30

    Crystalline silicon carbide alloys have a very high potential as transparent conductive window layers in thin-film solar cells provided they can be prepared in thin-film form and at compatible deposition temperatures. The low-temperature deposition of such material in microcrystalline form ({mu}c-Si:C:H) was realized by use of monomethylsilane precursor gas diluted in hydrogen with the Hot-Wire Chemical Vapor Deposition process. A wide range of deposition parameters has been investigated and the structural, electronic and optical properties of the {mu}c-SiC:H thin films have been studied. The material, which is strongly n-type from unintentional doping, has been used as window layer in n-side illuminated microcrystalline silicon solar cells. High short-circuit current densities are obtained due to the high transparency of the material resulting in a maximum solar cell conversion efficiency of 9.2%.

  2. Influence of film formation on light-trapping properties of randomly textured silicon thin-film solar cells

    Jovanov, Vladislav; Shrestha, Shailesh; Hüpkes, Jürgen; Ermes, Markus; Bittkau, Karsten; Knipp, Dietmar

    2014-08-01

    The influence of film formation on light-trapping properties of silicon thin-film solar cells prepared on randomly textured substrates was studied. Realistic interface morphologies were calculated with a three-dimensional (3D) surface coverage algorithm using the measured substrate morphology and nominal film thicknesses of the individual layers as input parameters. Calculated interface morphologies were used in finite-difference time-domain simulations to determine the quantum efficiency and absorption in the individual layers of the thin-film solar cells. The investigation shows that a realistic description of interface morphologies is required to accurately predict the light-trapping properties of randomly textured silicon thin-film solar cells.

  3. Luminescent down shifting effect of Ce-doped yttrium aluminum garnet thin films on solar cells

    Ce-doped yttrium aluminum garnet (YAG:Ce) thin films as luminescent down shifting (LDS) materials are introduced into the module of crystalline silicon solar cells. The films are deposited by RF magnetron sputtering on the lower surface of the quartz glass. They convert ultraviolet and blue light into yellow light. Experiments show that the introduction of YAG:Ce films improves the conversion efficiency from 18.45% of the cells to 19.27% of the module. The increasing efficiency is attributed to LDS effect of YAG:Ce films and the reduced reflection of short wavelength photons. Two intentionally selected samples with similar reflectivities are used to evaluate roughly the effect of LDS alone on the solar cells, which leads to a relative increase by 2.68% in the conversion efficiency

  4. Luminescent down shifting effect of Ce-doped yttrium aluminum garnet thin films on solar cells

    Shao, Guojian; Lou, Chaogang; Kang, Jian; Zhang, Hao

    2015-12-01

    Ce-doped yttrium aluminum garnet (YAG:Ce) thin films as luminescent down shifting (LDS) materials are introduced into the module of crystalline silicon solar cells. The films are deposited by RF magnetron sputtering on the lower surface of the quartz glass. They convert ultraviolet and blue light into yellow light. Experiments show that the introduction of YAG:Ce films improves the conversion efficiency from 18.45% of the cells to 19.27% of the module. The increasing efficiency is attributed to LDS effect of YAG:Ce films and the reduced reflection of short wavelength photons. Two intentionally selected samples with similar reflectivities are used to evaluate roughly the effect of LDS alone on the solar cells, which leads to a relative increase by 2.68% in the conversion efficiency.

  5. Thin film CdTe solar cells by close spaced sublimation: Recent results from pilot line

    CdTe is an attractive material to produce high efficient and low cost thin film solar cells. The semiconducting layers of this kind of solar cell can be deposited by the Close Spaced Sublimation (CSS) process. The advantages of this technique are high deposition rates and an excellent utilization of the raw material, leading to low production costs and competitive module prices. CTF Solar GmbH is offering equipment and process knowhow for the production of CdTe solar modules. For further improvement of the technology, research is done at a pilot line, which covers all relevant process steps for manufacture of CdTe solar cells. Herein, we present the latest results from the process development and our research activities on single functional layers as well as for complete solar cell devices. Efficiencies above 13% have already been obtained with Cu-free back contacts. An additional focus is set on different transparent conducting oxide materials for the front contact and a Sb2Te3 based back contact. - Highlights: ► Laboratory established on industrial level for CdTe solar cell research ► 13.0% cell efficiency with our standard front contact and Cu-free back contact ► Research on ZnO-based transparent conducting oxide and Sb2Te3 back contacts ► High resolution scanning electron microscopy analysis of ion polished cross section

  6. Copper and Transparent-Conductor Reflectarray Elements on Thin-Film Solar Cell Panels

    Dreyer, Philippe; Nicolay, Sylvain; Ballif, Christophe; Perruisseau-Carrier, Julien

    2013-01-01

    This work addresses the integration of reflectarray antennas (RA) on thin film Solar Cell (SC) panels, as a mean to save real estate, weight, or cost in platforms such as satellites or transportable autonomous antenna systems. Our goal is to design a good RA unit cell in terms of phase response and bandwidth, while simultaneously achieving high optical transparency and low microwave loss, to preserve good SC and RA energy efficiencies, respectively. Since there is a trade-off between the optical transparency and microwave surface conductivity of a conductor, here both standard copper and transparent conductors are considered. The results obtained at the unit cell level demonstrates the feasibility of integrating RA on a thin-film SC, preserving for the first time good performance in terms of both SC and RA efficiency. For instance, measurement at X-band demonstrate families of cells providing a phase range larger than 270{\\deg} with average microwave loss of -2.45dB (resp. -0.25dB) and average optical transpa...

  7. Laser crystallization induced multicrystalline silicon thin film solar cells on glass : European High-EF Project

    The European project HIGH-EF is aimed at developing a unique process for silicon thin films based solar cells on glass substrate. To provide high solar cells efficiency (? 12 percent), a combination of laser crystallization of a seed layer and an additional solid phase epitaxy of a thicker layer is realized. In a first step, the crystallization of the seed layer is obtained by scanning a focused in-line laser beam obtained by a specific optical lens system. In a second step, epitaxial growth of a large grains active silicon layer is achieved by solid phase epitaxy. Process optimization is supported by numerical simulations of both melting and crystallization process of the seed layer as well as epitaxial solid phase crystallization

  8. A non-resonant dielectric metamaterial for the enhancement of thin-film solar cells

    Recently, we have suggested a dielectric metamaterial composed of an array of submicron dielectric spheres located on top of an amorphous thin-film solar cell. We have theoretically shown that this metamaterial can decrease the reflection and simultaneously suppress the transmission through the photovoltaic layer because it transforms the incident plane wave into a set of focused light beams. This theoretical concept has been strongly developed and experimentally confirmed in the present paper. Here we consider the metamaterial for oblique angle illumination, redesign the solar cell and present a detailed experimental study of the whole structure. In contrast to our previous theoretical study we show that our omnidirectional light-trapping structure may operate better than the optimized flat coating obtained by plasma-enhanced chemical vapor deposition. (paper)

  9. A non-resonant dielectric metamaterial for enhancement of thin-film solar cells

    Omelyanovich, Mikhail; Simovski, Constantin

    2014-01-01

    Recently, we have suggested dielectric metamaterial composed as an array of submicron dielectric spheres located on top of an amorphous thin-film solar cell. We have theoretically shown that this metamaterial can decrease the reflection and simultaneously can suppress the transmission through the photovoltaic layer because it transforms the incident plane wave into a set of focused light beams. This theoretical concept has been strongly developed and experimentally confirmed in the present paper. Here we consider the metamaterial for oblique angle illumination, redesign the solar cell and present a detailed experimental study of the whole structure. In contrast to our precedent theoretical study we show that our omnidirectional light-trapping structure may operate better than the optimized flat coating obtained by plasma-enhanced chemical vapor deposition.

  10. Laser crystallization induced multicrystalline silicon thin film solar cells on glass : european HIGH-EF project

    The european project HIGH-EF is aimed at developing a unique process for silicon thin films based solar cells on glass substrate. To provide high solar cells efficiency (more than 12 percent) a combination of laser crystallization of a seed layer and an additional solid phase epitaxy of thicker layer is realized. In a first step, the crystallization of the seed layer is obtained by scanning a focused in-line laser beam obtained by a specific optical lens system. In a second step, epitaxial growth of a large grains active silicon layer is achieved by solid phase epitaxy. Process optimization is supported by numerical simulations of both melting and crystallization process of the seed layer as well as epitaxial solid phase crystallization

  11. Temperature dependent electrical characterization of thin film Cu2ZnSnSe4 solar cells

    Kask, E.; Krustok, J.; Giraldo, S.; Neuschitzer, M.; Lpez-Marino, S.; Saucedo, E.

    2016-03-01

    Impedance spectroscopy (IS) and currentvoltage characteristics measurements were applied to study properties of a Cu2ZnSnSe4 (CZTSe) thin film solar cell. IS measurements were done in the frequency range 20 Hz to 10 MHz. The measurement temperature was varied from 10?K to 325?K with a step ?T??=??5?K. Temperature dependence of V oc revealed an activation energy of 962 meV, which is in the vicinity of the band gap energy of CZTSe and hence the dominating recombination mechanism in this solar cell is bulk recombination. Different temperature ranges, where electrical properties change, were found. Interface states at grain boundaries with different properties were revealed to play an important role in impedance measurements. These states can be described by introducing a constant phase element in the equivalent circuit.

  12. Thin film solar cells on glass by transfer of monocrystalline Si films

    J. H. Werner

    1999-01-01

    Full Text Available Thin film solar cells based on monocrystalline Si films are transferred to a glass superstrate. Chemical vapor deposition serves to epitaxially deposit Si on quasi-monocrystalline Si films obtained from thermal crystallization of a double layer porous Si film on a Si wafer. A separation layer that forms during this crystallization process allows one to separate the epitaxial layer on top of the quasi-monocrystalline film from the starting Si wafer. We presently achieve an independently confirmed solar cell conversion efficiency of 9:26%. Ray tracing studies in combination with electrical device simulation indicate an efficiency potential of around 17% using simple device processing and moderate assumptions on minority carrier lifetime and surface recombination.

  13. Hydrophobic perfluoropolymer thin-film encapsulation for enhanced stability of inverted polymer solar cells

    We report hydrophobic perfluoropolymer thin-film encapsulation for enhancing the air ambient stability of inverted polymer solar cells (PSCs). Using a perfluoropolymer, poly(perfluorodecylmethacrylate) (PFDMA), as an encapsulation material, an orthogonal process that enables a solution-processing of encapsulation polymers to be coated directly on the inverted PSCs without damaging the underlying organic components is possible. Particularly, with PFDMA encapsulation, the air ambient stability was significantly enhanced, showing only an efficiency reduction of 23.3% after 456 hours of air exposure. The enhanced device stability can be attributed to the hydrophobic property of the PFDMA surface, which suppresses the transmission of air ambient gas molecules into the solar cells. Thus, the PFDMA coating can be beneficial in achieving high-stability organic electronics by using an easy-to-use route.

  14. Epitaxially grown polycrystalline silicon thin-film solar cells on solid-phase crystallised seed layers

    Highlights: • Crystallisation kinetic is used to analyse seed layer surface cleanliness. • Simplified RCA cleaning for the seed layer can shorten the epitaxy annealing duration. • RTA for the seed layer can improve the quality for both seed layer and epi-layer. • Epitaxial poly-Si solar cell performance is improved by RTA treated seed layer. - Abstract: This paper presents the fabrication of poly-Si thin film solar cells on glass substrates using seed layer approach. The solid-phase crystallised P-doped seed layer is not only used as the crystalline template for the epitaxial growth but also as the emitter for the solar cell structure. This paper investigates two important factors, surface cleaning and intragrain defects elimination for the seed layer, which can greatly influence the epitaxial grown solar cell performance. Shorter incubation and crystallisation time is observed using a simplified RCA cleaning than the other two wet chemical cleaning methods, indicating a cleaner seed layer surface is achieved. Cross sectional transmission microscope images confirm a crystallographic transferal of information from the simplified RCA cleaned seed layer into the epi-layer. RTA for the SPC seed layer can effectively eliminate the intragrain defects in the seed layer and improve structural quality of both of the seed layer and the epi-layer. Consequently, epitaxial grown poly-Si solar cell on the RTA treated seed layer shows better solar cell efficiency, Voc and Jsc than the one on the seed layer without RTA treatment

  15. Time Domain Characterization of Light Trapping States in Thin Film Solar Cells

    Pfeiffer W.

    2013-03-01

    Full Text Available Spectral interferometry of the backscattered radiation reveals coherence lifetimes of about 150 fs for nanolocalized electromagnetic modes in textured layered nanostructures as they are commonly used in thin film photovoltaics to achieve high cell efficiencies.

  16. Thin film solar cells with Si nanocrystallites embedded in amorphous intrinsic layers by hot-wire chemical vapor deposition.

    Park, Seungil; Parida, Bhaskar; Kim, Keunjoo

    2013-05-01

    We investigated the thin film growths of hydrogenated silicon by hot-wire chemical vapor deposition with different flow rates of SiH4 and H2 mixture ambient and fabricated thin film solar cells by implementing the intrinsic layers to SiC/Si heterojunction p-i-n structures. The film samples showed the different infrared absorption spectra of 2,000 and 2,100 cm(-1), which are corresponding to the chemical bonds of SiH and SiH2, respectively. The a-Si:H sample with the relatively high silane concentration provides the absorption peak of SiH bond, but the microc-Si:H sample with the relatively low silane concentration provides the absorption peak of SiH2 bond as well as SiH bond. Furthermore, the microc-Si:H sample showed the Raman spectral shift of 520 cm(-1) for crystalline phase Si bonds as well as the 480 cm(-1) for the amorphous phase Si bonds. These bonding structures are very consistent with the further analysis of the long-wavelength photoconduction tail and the formation of nanocrystalline Si structures. The microc-Si:H thin film solar cell has the photovoltaic behavior of open circuit voltage similar to crystalline silicon thin film solar cell, indicating that microc-Si:H thin film with the mixed phase of amorphous and nanocrystalline structures show the carrier transportation through the channel of nanocrystallites. PMID:23858866

  17. Sputtered CdTe thin film solar cells with Cu2Te/Au back contact

    In this work, Cu2Te/Au back contact for CdTe thin film solar cells were prepared by vacuum evaporation. Influence of annealing temperature on the structure and electrical properties of Cu2Te films were investigated by field emission scanning electron microscope, X-ray diffraction, and Hall effect measurement. Also, CdS/CdTe thin film solar cells were fabricated by magnetron sputtering process, which is favorable for large area deposition and mass production, and the photovoltaic characteristics were studied. As the annealing temperature was increased, the crystal structure transformed from Cu2Te for as-deposited film to Cu2−xTe hexagonal phase, and the grains in the film became bigger. The electrical resistivity was slightly higher by the annealing. The cell efficiency was significantly improved by the heat treatment, and showed a maximum value of 9.14% at 180 °C. From these results, Cu2Te/Au contact acts as the proper pseudo-ohmic contact onto CdTe film. However, further increase of annealing temperature caused the deterioration of cell performance. - Highlights: • Annealing effects of the vacuum evaporated Cu2Te films were investigated. • The transformation from Cu2Te to Cu2−xTe hexagonal phase occurred by annealing. • The performance of the solar cell was highly increased by annealing at 180 °C. • Cu2Te/Au contact acts as the proper pseudo-ohmic contact onto CdTe film

  18. Silicon Light: a European FP7 project aiming at high efficiency thin film silicon solar cells on foil. Monolithic series interconnection of flexible thin-film PV devices

    Soppe, W. [ECN Solar Energy, P.O. Box 1, 1755 ZG Petten (Netherlands); Haug, F.J. [Ecole Polytechnique Federale de Lausanne EPFL, Photovoltaics and Thin Film Electronics Laboratory, Rue A.-L. Breguet 2, 2000 Neuchatel (Switzerland); Couty, P. [VHFTechnologies SA, Rue Edouard-Verdan 2, CH-1400 Yverdon-les-Bains (Switzerland); Duchamp, M. [Technical University of Denmark, Center for Electron Nanoscopy, DK-2800 Kongens Lyngby (Denmark); Schipper, W. [Nanoptics GmbH, Innungstr.5, 21244 Buchholz (Germany); Krc, J. [University of Ljubljana, Faculty of Electrical Engineering, Trzaska 25, SI-1000 Ljubljana (Slovenia); Sanchez, G. [Universidad Politecnica de Valencia, I.U.I. Centro de Tecnologia Nanofotonica, 46022 Valencia (Spain); Leitner, K. [Umicore Thin Film Products AG, Balzers (Liechtenstein); Wang, Q. [Shanghai Jiaotong University, Research Institute of Micro/Nanometer Science and Technology, 800 Dongchuan Road, Min Hang, 200240 Shanghai (China)

    2011-09-15

    Silicon-Light is a European FP7 project, which started January 1st, 2010 and aims at development of low cost, high-efficiency thin film silicon solar cells on foil. Three main routes are explored to achieve these goals: (a) advanced light trapping by implementing nanotexturization through UV Nano Imprinting Lithography (UV-NIL); (b) growth of crack-free silicon absorber layers on highly textured substrates; (c) development of new TCOs which should combine the best properties of presently available materials like ITO and AZO. The paper presents the midterm status of the project results, showing model calculations of ideal nanotextures for light trapping in thin film silicon solar cells; the fabrication of masters and the replication and roll-to-roll fabrication of these nanotextures. Further, results on ITO variants with improved work function are presented. Finally, the status of cell fabrication on foils with nanotexture is shown. Microcrystalline and amorphous silicon single junction cells with stable efficiencies with more than 8% have been made, paving the way towards a-Si/{mu}c-Si tandem cells with more than 11% efficiency.

  19. Five roads towards increased optical absorption and high stable efficiency for thin film silicon solar cells

    Vaněček, Milan; Poruba, Aleš; Remeš, Zdeněk; Holovský, Jakub; Purkrt, Adam; Babchenko, Oleg; Hruška, Karel; Meier, J.; Kroll, U.

    Munich : WIP- Renewable Energies, 2009 - (Sinke, W.; Ossenbrink, H.; Helm, P.), s. 2286-2289 ISBN 3-936338-25-6. [European Photovoltaic Solar Energy Conference /24./. Hamburg (DE), 21.09.2009-25.09.2009] R&D Projects: GA MŠk(CZ) 7E09057 EU Projects: European Commission(XE) 214134 - N2P; European Commission(XE) 19670 - ATHLET Institutional research plan: CEZ:AV0Z10100521 Keywords : high stable efficiency * amorphous silicon * thin film solar cell * 3-dimensional nanostructuring * transparent conductive oxides Subject RIV: BM - Solid Matter Physics ; Magnetism http://dx.doi.org/10.4229/24thEUPVSEC2009-3BO.9.1

  20. Cu(In,GaSe2 thin films processed by co-evaporation and their application into solar cells

    J. Sastré-Hernández

    2011-01-01

    Full Text Available Polycrystalline Cu(In,GaSe2 (CIGS solar cells are attractive because low cost techniques can be used to obtain high efficiency thin film photovoltaic devices. Several research groups around the world have developed CIGS/CdS solar cells with efficiencies larger than 15% [1] using evaporation, making it an attractive and reliable technique for thin film deposition. Our PVD system is provided with MBE-type Knudsen cells to deposit CIGS thin films on glass/Molibdenum (Mo substrates. The deposition conditions for each metal source have been established by doing a deposition profile of temperature data vs. growth rate by co-evaporation to obtain CIGS thin film for solar cells. Characterization of the co-evaporated CIGS thin films was performed by X-ray diffraction (X-RD, scanning electron microscopy (SEM and energy dispersive x-ray spectroscopy (EDS techniques. Good quality polycrystalline films were obtained as shown by X-RD patterns. SEM micrographs show films having a very uniform appearance with large grain sizes (»1 ¹m. Photoluminescence (PL studies on CIGS samples with different Ga and Cu concentrations (Ga/Ga+In = 0.25 and 0.34 and (Cu/In+Ga = 0.83, 0.88 and 0.94 have been performed. The EDS results have shown that is possible to control very precisely the CIGS thin film composition using these Knudsen cells. Film thicknesses of »3-4 ¹m, were measured with an Ambios profilemeter XP 100 stylus type. A conversion efficiency of 10.9 % has been achieved for solar cells made from the co-evaporated absorbers.

  1. Thin film solar energy collector

    Aykan, Kamran (Monmouth Beach, NJ); Farrauto, Robert J. (Westfield, NJ); Jefferson, Clinton F. (Millburn, NJ); Lanam, Richard D. (Westfield, NJ)

    1983-11-22

    A multi-layer solar energy collector of improved stability comprising: (1) a substrate of quartz, silicate glass, stainless steel or aluminum-containing ferritic alloy; (2) a solar absorptive layer comprising silver, copper oxide, rhodium/rhodium oxide and 0-15% by weight of platinum; (3) an interlayer comprising silver or silver/platinum; and (4) an optional external anti-reflective coating, plus a method for preparing a thermally stable multi-layered solar collector, in which the absorptive layer is undercoated with a thin film of silver or silver/platinum to obtain an improved conductor-dielectric tandem.

  2. Studies of compositional dependent CZTS thin film solar cells by pulsed laser deposition technique: An attempt to improve the efficiency

    Highlights: ? Synthesis of CZTS thin films by PLD. ? Effect of stoichiometry, its deviation on the physical properties. ? Improvement in conversion efficiency using CZTS absorber layer. - Abstract: The performance of CZTS thin films deposited by using pulsed laser deposition technique is investigated as a function of target composition. The chemical composition ratio a = Cu/(Zn + Sn) of the target material has been varied from 0.8 to 1.2 in step of 0.1 by keeping Zn/Sn constant. The effect of the chemical composition in the precursor thin films on the structural, morphological, chemical and optical properties of the CZTS thin films has been investigated. X-ray diffraction and X-ray photoelectron spectroscopy studies showed that the annealed CZTS thin films are of a single kesterite crystal structure without any other secondary phases. The direct band gap energy of the CZTS thin films is found to decrease from 1.721.53 eV with increase of a. The estimated band-gap energy from the quantum efficiency measurements is about 1.54 eV. The solar cell fabricated with Glass/Mo/CZTS/CdS/ZnO:Al/Al structure grown using [a = Cu/(Zn + Sn) = 1.1] showed the best conversion efficiency of 4.13% with Voc = 700 mV, Jsc = 10.01 mA/cm2 and FF = 0.59.

  3. Effect of Ag doping on opto-electrical properties of CdS thin films for solar cell applications

    Highlights: • Polycrystalline CdS thin films are fabricated by means of Close Spaced Sublimation technique. • Ag is doped by simple ion-exchange technique in order to reduce resistivity of CdS thin films. • Remarkable reduction in resistivity without introducing many transparency losses. - Abstract: Cadmium sulfide (CdS) polycrystalline thin films of different thicknesses (ranging from 370 nm to 750 nm) were fabricated on corning glass substrates using Close Spaced Sublimation (CSS) technique. Optical and electrical investigation revealed that CdS thin films show an appreciable transparency (50–70% transmission) in visible range and a highly resistive behavior (106 Ω cm). Samples were doped by silver (Ag) at different concentrations, using ion exchange technique, in order to reduce the resistivity of CdS thin films and to improve their efficiency as a window layer for solar cell application. The doping of Ag in pure CdS thin films resulted into an increase of surface roughness and a decrease both in electrical resistivity and in transparency. By optimizing annealing parameters, we were able to properly control the optical properties of the present system. In fact, the Ag doping of pure CdS films has led to a decrease of the sample resistivity by three orders of magnitude (103 Ω cm) against a 20% cut in optical transmission

  4. Effect of Ag doping on opto-electrical properties of CdS thin films for solar cell applications

    Nazir, Adnan, E-mail: adnan.nazir@iit.it [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); School of Chemical and Materials Engineering, National University of Sciences and Technology, Islamabad (Pakistan); Toma, Andrea [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); Shah, Nazar Abbas [Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Panaro, Simone [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); Butt, Sajid [Department of Materials Science and Engineering, Institute of Space Technology (IST), Islamabad 44000 (Pakistan); School of Chemical and Materials Engineering, National University of Sciences and Technology, Islamabad (Pakistan); Sagar, Rizwan ur Rehman [Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Raja, Waseem [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); Rasool, Kamran [Micro and Nano Devices Group, Department of Metallurgy and Materials Engineering Pakistan, Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad 45650 (Pakistan); Maqsood, Asghari [Department of Physics, Air University, Islamabad (Pakistan)

    2014-10-01

    Highlights: Polycrystalline CdS thin films are fabricated by means of Close Spaced Sublimation technique. Ag is doped by simple ion-exchange technique in order to reduce resistivity of CdS thin films. Remarkable reduction in resistivity without introducing many transparency losses. - Abstract: Cadmium sulfide (CdS) polycrystalline thin films of different thicknesses (ranging from 370 nm to 750 nm) were fabricated on corning glass substrates using Close Spaced Sublimation (CSS) technique. Optical and electrical investigation revealed that CdS thin films show an appreciable transparency (5070% transmission) in visible range and a highly resistive behavior (10{sup 6} ? cm). Samples were doped by silver (Ag) at different concentrations, using ion exchange technique, in order to reduce the resistivity of CdS thin films and to improve their efficiency as a window layer for solar cell application. The doping of Ag in pure CdS thin films resulted into an increase of surface roughness and a decrease both in electrical resistivity and in transparency. By optimizing annealing parameters, we were able to properly control the optical properties of the present system. In fact, the Ag doping of pure CdS films has led to a decrease of the sample resistivity by three orders of magnitude (10{sup 3} ? cm) against a 20% cut in optical transmission.

  5. A two-layer structured PbI2 thin film for efficient planar perovskite solar cells

    Ying, Chao; Shi, Chengwu; Wu, Ni; Zhang, Jincheng; Wang, Mao

    2015-07-01

    In this paper, a two-layer structured PbI2 thin film was constructed by the spin-coating procedure using a 0.80 M PbI2 solution in DMF and subsequent close-spaced vacuum thermal evaporation using PbI2 powder as a source. The bottom PbI2 thin film was compact with a sheet-like appearance, parallel to the FTO substrate, and can be easily converted to a compact perovskite thin film to suppress the charge recombination of the electrons of the TiO2 conduction band and the holes of the spiro-OMeTAD valence band. The top PbI2 thin film was porous with nano-sheet arrays, perpendicular to the FTO substrate, and can be easily converted to a porous perovskite thin film to improve the hole migration from the perovskite to spiro-OMeTAD and the charge separation at the perovskite/spiro-OMeTAD interface. The planar perovskite solar cells based on the two-layer structured PbI2 thin film exhibited a photoelectric conversion efficiency of 11.64%, along with an open-circuit voltage of 0.90 V, a short-circuit photocurrent density of 19.29 mA cm-2 and a fill factor of 0.67.

  6. Controllable Electrochemical Synthesis of Reduced Graphene Oxide Thin-Film Constructed as Efficient Photoanode in Dye-Sensitized Solar Cells

    Soon Weng Chong

    2016-01-01

    Full Text Available A controllable electrochemical synthesis to convert reduced graphene oxide (rGO from graphite flakes was introduced and investigated in detail. Electrochemical reduction was used to prepare rGO because of its cost effectiveness, environmental friendliness, and ability to produce rGO thin films in industrial scale. This study aimed to determine the optimum applied potential for the electrochemical reduction. An applied voltage of 15 V successfully formed a uniformly coated rGO thin film, which significantly promoted effective electron transfer within dye-sensitized solar cells (DSSCs. Thus, DSSC performance improved. However, rGO thin films formed in voltages below or exceeding 15 V resulted in poor DSSC performance. This behavior was due to poor electron transfer within the rGO thin films caused by poor uniformity. These results revealed that DSSC constructed using 15 V rGO thin film exhibited high efficiency (η = 1.5211% attributed to its higher surface uniformity than other samples. The addition of natural lemon juice (pH ~ 2.3 to the electrolyte accelerated the deposition and strengthened the adhesion of rGO thin film onto fluorine-doped tin oxide (FTO glasses.

  7. Layer Transfer of Cu(In,Ga)Se2 Thin Film and Solar Cell Fabrication

    Minemoto, Takashi; Anegawa, Takaya; Osada, Shintaro; Takakura, Hideyuki

    2010-01-01

    Cu(In,Ga)Se2 (CIGS) thin films were transferred to alternative substrates by a lift-off process, and solar cells were fabricated using the transferred films. CIGS films were grown on Mo/soda-lime glass (SLG) substrates by a three-stage evaporation process. The CIGS films were transferred to two alternative substrates: a rigid SLG and a flexible polyimide film. In the lift-off process, an intentional sacrificial layer between CIGS and Mo back contact layers was not prepared. CIGS solar cells with In2O3:Sn/ZnO/CdS/CIGS/Mo/conductive-epoxy/alternative-substrates structure were fabricated. Both solar cells showed almost half of the conversion efficiencies of a CIGS solar cell fabricated by a standard process. This is because of poor short circuit current and fill factor due to voltage-dependent current collection and high series resistance. Modifications of the composition profile of the CIGS layer and back contact property will improve the device performance. These results demonstrated the possibility of using the lift-off process for CIGS solar cells to widen the variety of substrate material choice.

  8. Surface textured molybdenum doped zinc oxide thin films prepared for thin film solar cells using pulsed direct current magnetron sputtering

    In this study, we examined the effect of etching on the electrical properties, transmittance, and scattering of visible light in molybdenum doped zinc oxide, ZnO:Mo (MZO) thin films prepared by pulsed direct current magnetron sputtering. We used two different etching solutions - KOH and HCl - to alter the surface texture of the MZO thin film so that it could trap light. The experimental results showed that an MZO film with a minimum resistivity of about 8.9 x 10-4 Ω cm and visible light transitivity of greater than 80% can be obtained without heating at a Mo content of 1.77 wt.%, sputtering power of 100 W, working pressure of 0.4 Pa, pulsed frequency of 10 kHz, and film thickness of 500 nm. To consider the effect of resistivity and optical diffuse transmittance, we performed etching of an 800 nm thick MZO thin film with 0.5 wt.% HCl for 3-6 s at 300 K. Consequently, we obtained a resistivity of 1.74-2.75 x 10-3 Ω cm, total transmittance at visible light of 67%-73%, diffuse transmittance at visible light of 25.1%-28.4%, haze value of 0.34-0.42, and thin film surface crater diameters of 220-350 nm.

  9. Quantum efficiency as a device-physics interpretation tool for thin-film solar cells

    Nagle, Timothy J.

    2007-12-01

    Thin-film solar cells made from CdTe and CIGS p-type absorbers are promising candidates for generating pollution-free electricity. The challenge faced by the thin-film photovoltaics (PV) community is to improve the electrical properties of devices, without straying from low-cost, industry-friendly techniques. This dissertation will focus on the use of quantum-efficiency (QE) measurements to deduce the device physics of thin-film devices, in the hope of improving electrical properties and efficiencies of PV materials. Photons which are absorbed, but not converted into electrical energy can modify the energy bands in the solar cell. Under illumination, photoconductivity in the CdS window layer can result in bands different from those in the dark. QE data presented here was taken under a variety of light-bias conditions. These results suggest that 0.10 sun of white-light bias incident on the CdS layer is usually sufficient to achieve accurate QE results. QE results are described by models based on carrier collection by drift and diffusion, and photon absorption. These models are sensitive to parameters such as carrier mobility and lifetime. Comparing calculated QE curves with experiments, it was determined that electron lifetimes in CdTe are less than 0.1 ns. Lifetime determinations also suggest that copper serves as a recombination center in CdTe. The spatial uniformity of QE results has been investigated with the LBIC apparatus, and several experiments are described which investigate cell uniformity. Electrical variations that occur in solar cells often occur in a nonuniform fashion, and can be detected with the LBIC apparatus. Studies discussed here include investigation of patterned deposition of Cu in back-contacts, the use of high-resistivity TCO layers to mitigate nonuniformity, optical effects, and local shunts. CdTe devices with transparent back contacts were also studied with LBIC, including those that received a strong bromine/dichrol/hydrazine (BDH) etch and those that received a weak bromine etch at the back contact. Back-side results showed improved uniformity in BDH-etched devices, attributed to better back contacts in these devices. In thin-absorber devices, the uniformity trend would likely extend to front-side measurements.

  10. Determination of optical and mechanical properties of Nb2O5 thin films for solar cells application

    Highlights: • Niobium pentoxide films were prepared by microwave assisted magnetron sputtering. • Optical and mechanical properties of Nb2O5 thin films were investigated. • The surface of thin films was homogenous, crack free and exhibited low RMS roughness. • Prepared Nb2O5 coatings were well transparent from ca., 350 nm. • Hardness of deposited coatings was ca., 7 GPa. - Abstract: In this paper investigation results of niobium pentoxide thin films deposited by microwave assisted reactive magnetron sputtering process were described. Surface of prepared coatings was examined with the aid of atomic force microscope (AFM) operating in the contact-mode and in ultra high vacuum conditions. The surface of thin films was homogenous, crack free and exhibit low root mean square (RMS) roughness of about 0.34 nm. X-ray photoelectron spectroscopy (XPS) studies were performed to determine the chemical states of the niobium at the surface of thin films. Contact angle and surface free energy were additionally investigated to examine the surface properties of the deposited coatings. Optical properties of the Nb2O5 thin films showed, that prepared coatings were well transparent from 350 nm to longer wavelength range. Based on transmission and reflection measurements the values of refractive index and extinction coefficient were determined. The antireflective coating based on Nb2O5 thin films for solar cells application was proposed. The hardness and Young's modulus measurements were performed by the nanoindentation technique. These investigations revealed that the hardness of the deposited coatings was ca., 7 GPa. Also scratch tests were applied, which have shown that the Nb2O5 thin films were scratch resistant

  11. Recent Progress in CuInS2 Thin-Film Solar Cell Research at NASA Glenn

    Jin, M. H.-C.; Banger, K. K.; Kelly, C. V.; Scofield, J. H.; McNatt, J. S.; Dickman, J. E.; Hepp, A. F.

    2005-01-01

    The National Aeronautics and Space Administration (NASA) is interested in developing low-cost highly efficient solar cells on light-weight flexible substrates, which will ultimately lower the mass-specific power (W/kg) of the cell allowing extra payload for missions in space as well as cost reduction. In addition, thin film cells are anticipated to have greater resistance to radiation damage in space, prolonging their lifetime. The flexibility of the substrate has the added benefit of enabling roll-to-roll processing. The first major thin film solar cell was the "CdS solar cell" - a heterojunction between p-type CuxS and n-type CdS. The research on CdS cells started in the late 1950s and the efficiency in the laboratory was up to about 10 % in the 1980s. Today, three different thin film materials are leading the field. They include amorphous Si, CdTe, and Cu(In,Ga)Se2 (CIGS). The best thin film solar cell efficiency of 19.2 % was recently set by CIGS on glass. Typical module efficiencies, however, remain below 15 %.

  12. Thin film solar cells based on the ternary compound Cu2SnS3

    Alongside with Cu2ZnSnS4 and SnS, the p-type semiconductor Cu2SnS3 also consists of only Earth abundant and low-cost elements and shows comparable opto-electronic properties, with respect to Cu2ZnSnS4 and SnS, making it a promising candidate for photovoltaic applications of the future. In this work, the ternary compound has been produced via the annealing of an electrodeposited precursor in a sulfur and tin sulfide environment. The obtained absorber layer has been structurally investigated by X-ray diffraction and results indicate the crystal structure to be monoclinic. Its optical properties have been measured via photoluminescence, where an asymmetric peak at 0.95 eV has been found. The evaluation of the photoluminescence spectrum indicates a band gap of 0.93 eV which agrees well with the results from the external quantum efficiency. Furthermore, this semiconductor layer has been processed into a photovoltaic device with a power conversion efficiency of 0.54%, a short circuit current of 17.1 mA/cm2, an open circuit voltage of 104 mV hampered by a small shunt resistance, a fill factor of 30.4%, and a maximal external quantum efficiency of just less than 60%. In addition, the potential of this Cu2SnS3 absorber layer for photovoltaic applications is discussed. - Highlights: ► Fabrication of a pn-junction based thin film solar cell based on Cu2SnS3. ► Electro-optical properties of the Cu2SnS3 based solar cell and its limits. ► The potential of Cu2SnS3 based solar cells in terms of its photovoltaic application. ► Structural, morphological, and optical properties of a Cu2SnS3 thin film.

  13. Near-field assisted nanoscale patterning for improved absorption in thin film silicon solar cell

    Murukeshan, V. M.; Prabhathan, P.; Sidharthan, R.

    2014-10-01

    Near field optics concepts have introduced a paradigm shift in a wide variety of engineering fields in the recent past and the most significant applications of this fundamental physics concepts have been in the applied engineering problems such as improved broad band light absorption thereby enhancing the conversion efficiency of thin silicon solar cells. Also, for writing patterned structures or features using non contact optical methodologies have enabled near field optics assisted fabrication and related applications. The technology involving optics concepts and methodologies targeting energy sector have seen the impact of the same with a challenging trend to achieve smaller features or devices with micro- or nano-scale features. This demands automatically the need for achieving much smaller features beyond the forecasted sub- 30nm feature patterning methodologies. To meet such demands, a new branch of near- field optical concepts for improving patterning resolution has started developing which have been receiving considerable attention for its ability to produce high density sub-wavelength features that can find tremendous energy harvesting applications. This paper in this context mainly focuses on the review of different near field optical concepts and approaches developed for patterning by the author's group at NTU. Different concepts were explored incorporating surface Plasmon waves ( LSPs, SPPs, LRSPs), gap modes as well as their interference in order to high resolution features and pattern dimensions at nano-scales. The absorbance of near band gap light is small and hence structuring of thin film solar cell is very important for increasing the absorbance by light trapping. The manuscript conclude by correlating the above said aspects and the challenges in achieving improved light conversion in thin film solar cells.

  14. Thin-Film Solar Cells on Polymer Substrates for Space Power

    Hepps, A. F.; McNatt, Jeremiah; Morel, D. L.; Ferckides, C. S.; Jin, M. H.; Orbey, N.; Cushman, M.; Birkmire, R. W.; Shafarman, W. N.; Newton, R.

    2004-01-01

    Photovoltaic arrays have played a key role in power generation in space. The current technology will continue to evolve but is limited in the important mass specific power metric (MSP or power/weight ratio) because it is based on bulk crystal technology. Solar cells based on thin-film materials offer the promise of much higher MSP and much lower cost. However, for many space applications, a 20% or greater AM0 efficiency (eta) may be required. The leading thin-film materials, amorphous Si, CuInSe, and CdTe have seen significant advances in efficiency over the last decade but will not achieve the required efficiency in the near future. Several new technologies are herein described to maximize both device eta and MSP. We will discuss these technologies in the context of space exploration and commercialization. One novel approach involves the use of very lightweight polyimide substrates. We describe efforts to enable this advance including materials processing and device fabrication and characterization. Another approach involves stacking two cells on top of each other. These tandem devices more effectively utilize solar radiation by passing through non-absorbed longer wavelength light to a narrow-bandgap bottom cell material. Modeling of current devices in tandem format indicates that AM0 efficiencies near 20% can be achieved with potential for 25% in the near future. Several important technical issues need to be resolved to realize the benefits of lightweight technologies for solar arrays, such as: monolithic interconnects, lightweight array structures, and new ultra-light support and deployment mechanisms. Recent advances will be stressed.

  15. Quantification of Power Losses of the Interdigitated Metallization of Crystalline Silicon Thin-Film Solar Cells on Glass

    Sergey Varlamov; Peter J. Gress

    2012-01-01

    The metallization grid pattern is one of the most important design elements for high-efficiency solar cells. This paper presents a model based on the unit cell approach to accurately quantify the power losses of a specialized interdigitated metallization scheme for polycrystalline silicon thin-film solar cells on glass superstrates. The sum of the power losses can be minimized to produce an optimized grid-pattern design for a cell with specific parameters. The model is simulated with the stan...

  16. Basella alba rubra spinach pigment-sensitized TiO2 thin film-based solar cells

    Gokilamani, N.; Muthukumarasamy, N.; Thambidurai, M.; Ranjitha, A.; Velauthapillai, Dhayalan

    2015-03-01

    Nanocrystalline TiO2 thin films have been prepared by sol-gel dip coating method. The X-ray diffraction results showed that TiO2 thin films annealed at 400, 450 and 500 °C are of anatase phase and the peak corresponding to the (101) plane is present in all the samples. The grain size of TiO2 thin films was found to increase with increasing annealing temperature. The grain size is found to be 20, 25 and 33 nm for the films annealed at 400, 450 and 500 °C. The structure of the TiO2 nanocrystalline thin films have been examined by high-resolution transmission electron microscope, Raman spectroscopy and FTIR spectroscopy. TiO2 thin films were sensitized by natural dyes extracted from basella alba rubra spinach. It was found that the absorption peak of basella alba rubra extract is at about 665 nm. The dye-sensitized TiO2-based solar cell sensitized using basella alba rubra exhibited a J sc of 4.35 mA cm-2, V oc of 0.48 V, FF of 0.35 and efficiency of 0.70 %. Natural dyes as sensitizers for dye-sensitized solar cells are promising because of their environmental friendliness, low-cost production and fully biodegradable.

  17. Ternary Precursors for Depositing I-III-VI2 Thin Films for Solar Cells via Spray CVD

    Banger, K. K.; Hollingsworth, J. A.; Jin, M. H.-C.; Harris, J. D.; Duraj, S. A.; Smith, M.; Scheiman, D.; Bohannan, E. W.; Switzer, J. A.; Buhro, W. E.

    2002-01-01

    The development of thin-film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution to fabricating solar arrays with high specific power (W/kg). Thin-film fabrication studies demonstrate that ternary single source precursors (SSP's) can be used in either a hot or cold-wall spray chemical vapour deposition (CVD) reactor, for depositing CuInS2, CuGaS2, and CuGaInS2 at reduced temperatures (400 to 450 C), which display good electrical and optical properties suitable for photovoltaic (PV) devices. X-ray diffraction studies, energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM) confirmed the formation of the single phase CIS, CGS, CIGS thin-films on various substrates at reduced temperatures.

  18. Single source precursors for fabrication of I-III-VI2 thin-film solar cells via spray CVD

    The development of thin-film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution to fabricating solar arrays with high specific power (W/kg). Thin-film fabrication studies demonstrate that ternary single source precursors can be used in either a hot, or cold-wall spray chemical vapour deposition reactor, for depositing CuInS2, CuGaS2 and CuGaInS2 at reduced temperatures (400-450 sign C), which display good electrical and optical properties suitable for photovoltaic devices. X-ray diffraction studies, energy dispersive spectroscopy and scanning electron microscopy confirmed the formation of the single phase CIS, CGS, CIGS thin-films on various substrates at reduced temperatures

  19. Heterojunction solar cells with integrated Si and ZnO nanowires and a chalcopyrite thin film

    ZnO nanowires (NWs) have been successfully synthesized using a hydrothermal technique on both glass and silicon substrates initially coated with a sputtered ZnO thin film layer. Varying ZnO seed layer thicknesses were deposited to determine the effect of seed layer thickness on the quality of ZnO NW growth. The effect of growth time on the formation of ZnO NWs was also studied. Experimental results show that these two parameters have an important effect on formation, homogeneity and vertical orientation of ZnO NWs. Silicon nanowires were synthesized by a Ag-assisted electroless etching technique on an n-type Si (100) wafer. SEM observations have revealed the formation of vertically-aligned Si NWs with etching depth of ?700 nm distributed over the surface of the Si. An electron-beam evaporated chalcopyrite thin film consisting of p-type AgGa0.5In0.5Se2 with ?800 nm thickness was deposited on the n-type ZnO and Si NWs for the construction of nanowire based heterojunction solar cells. For the Si NW based solar cell, from a partially illuminated area of the solar cell, the open-circuit voltage, short-circuit current density, fill factor and power conversion efficiency were 0.34 V, 25.38 mA cm?2, 63% and 5.50%, respectively. On the other hand, these respective parameters were 0.26 V, 3.18 mA cm?2, 35% and 0.37% for the ZnO NW solar cell. - Highlights: ZnO nanowires using hydrothermal technique have been synthesized successfully. Silicon nanowires were synthesized by Ag-assisted electroless etching technique. A p-type AGIS was deposited on the n-type ZnO and n-Si NWs for nanowire based solar cells. Power conversion efficiency of 5.50% was obtained for Si nanowires based solar cell

  20. Application of plasmonic silver island films in thin-film silicon solar cells

    Silver nanoparticles can be used as light scattering elements for enhancing solar cell energy conversion efficiencies. The objective of our work is to gain more insight into the optical properties of silver nanoparticle films and their effect on the performance of solar cells. We use a common self-assembly technique to fabricate a range of silver island films on transparent substrates and measure their reflectance and transmittance for visible and near infrared light. We demonstrate that it is possible to represent silver island films by an effective medium with the same optical properties. The observed strong dependence on illumination side of the reflectance and absorptance, attributed to driving field effects, is reproduced very well. Thin-film silicon solar cells with embedded silver island films were fabricated and it was found that their performance is reduced due to parasitic absorption of light in the silver island film. Simulations of these solar cells, where the silver island film is represented as an effective medium layer, show a similar trend. This highlights the importance of minimizing parasitic absorption

  1. Inductively coupled hydrogen plasma processing of AZO thin films for heterojunction solar cell applications

    Highlights: A high-density plasma reactor of inductively coupled plasma source is used in this work. The conductivity and transmittance can be enhanced simultaneously in the hydrogen process. The formation of additional donors and passivation due to the hydrogen plasma processing. The photovoltaic improvement due to the improved AZO layer and hetero-interface quality in the solar cells. - Abstract: Al-doped ZnO (AZO) thin films deposited by means of RF magnetron sputtering were processed in a low frequency inductively coupled plasma of H2, aiming at heterojunction (HJ) solar cell applications. A variety of characterization results show that the hydrogen plasma processing exerts a significant influence on the microstructures, electrical and optical properties of the AZO films. The incorporation of hydrogen under the optimum treatment simultaneously promoted the transmittance and conductivity due to the hydrogen associated passivation effect on the native defects and the formation of shallow donors in the films, respectively. A p-type c-Si based HJ solar cell with a front AZO contact was also treated in as-generated non-equilibrium hydrogen plasma and the photovoltaic performance of the solar cell was prominently improved. The underlying mechanism was discussed in terms of the beneficial impacts of high-density hydrogen plasma on the properties of AZO itself and the hetero-interfaces involved in the HJ structure (interface defect and energy band configuration)

  2. Silicontetrachloride based microcrystalline silicon for application in thin film silicon solar cells

    The replacement of the process gas silane by silicontetrachloride for the deposition of microcrystalline silicon thin films is explored. The films were prepared by plasma enhanced chemical vapor deposition from mixtures of silicontetrachloride and hydrogen. Deposition conditions similar as employed for efficient silane-based microcrystalline silicon solar cells of high deposition rate were applied. Structural and electronic properties of the films are studied by infrared optical absorption and Raman spectroscopies and conductivity measurements. Increasing the flow ratio of silicontetrachloride to hydrogen, the transition from the crystalline to the amorphous state is found to occur in a similar range of flow ratio as in silane-based material. The lowest porosity is observed for a crystalline fraction near 80%. Porosity, void-related microstructure and chlorine content are found to decrease with increasing substrate temperature. For boron doped material deposited at a substrate temperature of 250 deg. C, conductivity values exceeding 50 (? cm)-1 were achieved. This latter material was incorporated as p-layer into microcrystalline pin silicon solar cells. Solar cell efficiencies similar as for solar cells with a silane-based p-layer were obtained

  3. Thin film CIGS solar cells with a novel low cost process - Final report

    Tiwari, A. N.; Romanyuk, Y.

    2010-01-15

    Novel manufacturing routes for efficient and low-cost Cu(In,Ga)Se{sub 2} (called CIGS) thin film solar cells are explored and patented. CIGS has proven its suitability for highly efficient and extremely stable solar cells. The low-cost methods allow impurity free material synthesis, fast large-area deposition, high material utilization and a very short energy payback time with drastically lower manufacturing costs. Two non-vacuum, solution-based approaches are investigated to deposit thin layers of CIGS. The first approach considers incorporation of copper into indium gallium selenide precursor layers by ion-exchange from aqueous or organic solutions. Organic solutions provide faster copper incorporation and do not corrode the metal back contact. Solar cells processed from selenized precursor films exhibit efficiencies of up to 4.1%. The second approach with paste coating of inorganic salt solution results in a solar cell efficiency of 4% (record 6.7%), where further improvements are hindered by the presence of the residual carbon layer. Using alternative organic binders, pre-deposited selenium layers, non-binder recipes helps to avoid the carbon layer although the obtained layers are inhomogeneous and contain impurity phases. A patent for the ion-exchange approach is pending, and the obtained research results on the paste coating approach will be scrutinized during new European FP7 project 'NOVA-CIGS'. (authors)

  4. Silicon-Light: a European FP7 Project Aiming at High Efficiency Thin Film Silicon Solar Cells on Foil

    Soppe, W.; Haug, F.-J.; Couty, P.; Duchamp, Martial; Schipper, W.; Krc, J.; Sanchez, G.; Leitner, K.; Wang, Qin; Ossenbrink, H.; Jager-Waldau, A.; Helm, P.

    Silicon-Light is a European FP7 project, which started January 1st, 2010 and aims at development of low cost, high-efficiency thin film silicon solar cells on foil. Three main routes are explored to achieve these goals: a) advanced light trapping by implementing nanotexturization through UV Nano...

  5. Fabrication of thin film silicon solar cells on plastic substrate by very high frequency PECVD

    Rath, J.K.; Brinza, M.; Liu, Y.; Schropp, R.E.I. [Utrecht University, Faculty of Science, Debye Institute of Nanomaterials Science, Section Nanophotonics-Physics of Devices, P.O. Box 80000, 3508 TA Utrecht (Netherlands); Borreman, A. [Helianthos b.v., a Nuon Company (Netherlands)

    2010-09-15

    The paper describes the way to transfer process technology of state-of-the-art high efficiency thin film silicon solar cells fabrication on cheap plastic (such as PET or PEN) substrates, by two completely different approaches: (i) by transfer process (Helianthos concept) of thin film silicon cells deposited at high substrate temperature, T{sub s} ({proportional_to}200 C) and (ii) direct deposition on temperature sensitive substrates at low T{sub s} ({proportional_to}100 C). Adaptation of the process parameters and cell processing to the requirement of the flexible/plastic substrate is the most crucial step. In-situ diagnosis of the plasma has been done to understand the effect of inter-electrode distance, substrate temperature and hydrogen dilution on the gas phase conditions. Whereas, for the transfer process, the inter-electrode distance is a critical deposition condition that needs to be adapted for the flexible substrates, the direct deposition on plastic substrates has an added issue of loss in material quality and the deposition rate due to depositions at low T{sub s}. Our studies indicate that ion energy is crucial for obtaining compact films at low temperature and high hydrogen dilution helps to compensate the loss of ion energy at low substrate temperatures. Efficiencies of {proportional_to}5.9% and 6.2% have been obtained for n-i-p type a-Si cells on PET and PEN substrates, respectively, using direct deposition. Using an adapted inter-electrode distance, an a-Si/nc-Si tandem cell on plastic (polyester) substrate with an efficiency of 8.1% has been made by Helianthos cell transfer process. (author)

  6. Nanoimprint-textured glass superstrates for light trapping in crystalline silicon thin-film solar cells

    Köppel, G.; Preidel, V.; Mangold, S.; Rudigier-Voigt, E.; Hývl, Matěj; Fejfar, Antonín; Rech, B.; Becker, C.

    Amsterdam : Elsevier Ltd, 2015 - (Gordon, I.; Conibeer, G.; Krc, J.; Slaoui, A.; Niki, S.), s. 118-126 ISSN 1876-6102. - (84). [EMRS 2015 Spring meeting – Symposium C on Advanced Inorganic Materials and Structures for Photovoltaics. Lille (FR), 11.05.2015-15.05.2015] R&D Projects: GA ČR GA13-25747S; GA ČR GA13-12386S; GA MŠk(CZ) LM2011026; GA ČR GB14-37427G Grant ostatní: AVČR(CZ) M100101216 Institutional support: RVO:68378271 Keywords : nanoimprint lithography * light trapping * polycrystalline silicon thin-film solar cells Subject RIV: BM - Solid Matter Physics ; Magnetism

  7. Large CZTS Nanoparticles Synthesized by Hot-Injection for Thin Film Solar Cells

    Engberg, Sara Lena Josefin; Lam, Yeng Ming; Schou, Jørgen

    The kesterite material, Cu2ZnSn(SxSe1-x)4 (CZTS), shows great promise as the absorber layer for future thin film solar cells. Solution processing allows for comparatively fast and inexpensive fabrication, and holds the record efficiency in the kesterite family. However, for nanoparticle (NP......) solution processing to be a feasible fabrication route, the amount of carbon in the film has to be limited. In our work, we try to limit the organic material in the film by synthesizing larger NPs. Larger particles can be obtained by longer reaction durations, slower reaction rates of the precursors, or...... slower injection rates of the sulfur/selenium precursors. In our group, we have synthesized NPs larger than 200 nm by controlling the monomer concentration during growth. Transmission electron microscopy (TEM) allows us to image the NPs and determine their individual composition. Size-selective methods...

  8. Studying nanostructured nipple arrays of moth eye facets helps to design better thin film solar cells

    Nipples on the surface of moth eye facets exhibit almost perfect broadband anti-reflection properties. We have studied the facet surface micro-protuberances, known as corneal nipples, of the chestnut leafminer moth Cameraria ohridella by atomic force microscopy, and simulated the optics of the nipple arrays by three-dimensional electromagnetic simulation. The influence of the dimensions and shapes of the nipples on the optics was studied. In particular, the shape of the nipples has a major influence on the anti-reflection properties. Furthermore, we transferred the structure of the almost perfect broadband anti-reflection coatings to amorphous silicon thin film solar cells. The coating that imitates the moth-eye array allows for an increase of the short circuit current and conversion efficiency of more than 40%.

  9. Double AAO nanogratings for broad spectrum absorption enhancement in thin film Si solar cells

    Qin, F. F.; Zhang, H. M.; Wang, C. X.; Zhang, J. J.; Guo, C.

    2015-12-01

    In this paper, we presented a double light trapping structure containing anodic aluminum oxide (AAO) nanogratings on both the surface and rear of thin film crystalline silicon (c-Si) solar cell. Finite difference time domain (FDTD) method was used to study the light absorption enhancement of this design. Simulation results show that, the double light trapping structure can highly increase the light absorption in the wavelengths from 280 to 1100 nm. The relative enhancement of short-circuit current density (Jsc) in this situation is 137%. Besides, the double light trapping structure can highly reduce the influence of incident angle on light absorption. The relative position of AAO pore on the surface and rear has very little influence on light trapping.

  10. Dip coated nanocrystalline CdZnS thin films for solar cell application

    Dongre, J. K.; Chaturvedi, Mahim; Patil, Yuvraj; Sharma, Sandhya; Jain, U. K.

    2015-07-01

    Nanocrystalline cadmium sulfide (CdS) and zinc cadmium sulfide (ZnCdS) thin films have been grown via simple and low cost dip coating technique. The prepared films are characterized by X-ray diffraction (XRD), atomic force microscopic (AFM) and UV-VIS spectrophotometer techniques to reveal their structural, morphological and optical properties. XRD shows that both samples grown have zinc blende structure. The grain size is calculated as 6.2 and 8 nm using Scherrer's formula. The band gap value of CdS and CdZnS film is estimated to be 2.58 and 2.69 eV respectively by UV-vis spectroscopy. Photoelectrochemical (PEC) investigations are carried out using cell configuration as n-CdZnS/(1M NaOH + 1M Na2S + 1M S)/C. The photovoltaic output characteristic is used to calculate fill-factor (FF) and solar conversion efficiency (η).

  11. Experimental Evaluation of the Light Trapping Potential of Optical Nanostructures for Thin-Film Silicon Solar Cells

    Battaglia, Corsin; Escarre?, Jordi; Sderstrm, Karin; Boccard, M.; Ballif, C.

    2012-01-01

    We describe a method based on nanoimprinting and non-absorbing insulating silicon nitride electrodes for evaluating the light trapping potential of photonic nanostructures for thin-film silicon solar cells. We validate our method by relating the optical reflectance of the full solar cell stack to the external quantum efficiency of functional cells. Our method provides a useful experimental tool to compare different nanostructures circumventing complications arising from parasitic absorption a...

  12. Effects of Bi Incorporation on Cu(In1-x,Gax)Se2 Thin Films and Solar Cells

    Nakakoba, Hiroya; Yatsushiro, Yuta; Mise, Takahiro; Kobayashi, Taizo; Nakada, Tokio

    2012-10-01

    The effects of bismuth (Bi) incorporation into Cu(In1-x,Gax)Se2 (CIGS) thin films and solar cells have been investigated. 10-50-nm-thick Bi thin layers were deposited onto Mo-coated soda-lime glass (SLG) and SiOx-coated SLG substrates by vacuum evaporation. CIGS thin films were then deposited by a three-stage process at substrate temperatures of 450-550 °C. The grain growth of CIGS thin films was enhanced, and the open-circuit voltage and hence the conversion efficiency was improved by the Bi incorporation when the SLG substrates were used. However, little effect was observed when the alkali barrier SiOx layer was deposited on SLG substrates. As a result, we found that the Bi incorporation is beneficial for improving the cell performance when sodium exists simultaneously in CIGS layers.

  13. Effects of Antimony Doping on Cu(In1-x,Gax)Se2 Thin Films and Solar Cells

    Yatsushiro, Yuta; Nakakoba, Hiroya; Mise, Takahiro; Kobayashi, Taizo; Nakada, Tokio

    2012-10-01

    The effects of antimony (Sb) doping into Cu(In1-x,Gax)Se2 (CIGS) thin films and solar cells have been investigated. 10-50-nm-thick Sb thin layers were deposited onto Mo-coated sodalime glass (SLG) and SiOx-coated SLG substrates by vacuum evaporation. CIGS thin films were then deposited by a three-stage process at substrate temperatures of 450-550 °C. The grain growth of CIGS thin films was enhanced, and the open-circuit voltage and hence the conversion efficiency improved with the Sb doping when the SLG substrates were used. However, little or no effect was observed when the alkali barrier SiOx layer was deposited on SLG substrates. As a result, we found that Sb doping is beneficial for improving the cell performance when sodium exists simultaneously in CIGS layers.

  14. Development of Earth-Abundant Tin(II) Sulfide Thin-Film Solar Cells by Vapor Deposition

    Sinsermsuksakul, Prasert

    2013-01-01

    To sustain future civilization, the development of alternative clean-energy technologies to replace fossil fuels has become one of the most crucial and challenging problems of the last few decades. The thin film solar cell is one of the major photovoltaic technologies that is promising for renewable energy. The current commercial thin film PV technologies are based on \\(Cu(In,Ga)Se_2\\) and CdTe. Despite their success in reducing the module cost below $1/Wp, these absorber materials face limit...

  15. ?-FeSi2 as the bottom absorber of triple-junction thin-film solar cells: A numerical study

    Using ?-FeSi2 as the bottom absorber of triple-junction thin-film solar cells is investigated by a numerical method for widening the long-wave spectral response. The presented results show that the ?-FeSi2 subcell can contribute 0.273 V of open-circuit voltage to the a-Si/?c-Si/?-FeSi2 triple-junction thin-film solar cell. The optimized absorber thicknesses for a-Si, ?c-Si, and ?-FeSi2 subcells are 260 nm, 900 nm, and 40 nm, respectively. In addition, the temperature coefficient of the conversion efficiency of the a-Si/?c-Si/?-FeSi2 cell is ?0.308%/K, whose absolute value is only greater than that of the a-Si subcell. This result indicates that the a-Si/?c-Si/?-FeSi2 triple-junction solar cell has a good temperature coefficient. As a result, using ?-FeSi2 as the bottom absorber can improve the thin-film solar cell performance, and the a-Si/?c-Si/?-FeSi2 triple-junction solar cell is a promising structure configuration for improving the solar cell efficiency

  16. Characteristics of in-substituted CZTS thin film and bifacial solar cell.

    Ge, Jie; Chu, Junhao; Jiang, Jinchun; Yan, Yanfa; Yang, Pingxiong

    2014-12-10

    Implementing bifacial photovoltaic devices based on transparent conducting oxides (TCO) as the front and back contacts is highly appealing to improve the efficiency of kesterite solar cells. The p-type In substituted Cu2ZnSnS4 (CZTIS) thin-film solar cell absorber has been fabricated on ITO glass by sulfurizing coelectroplated Cu-Zn-Sn-S precursors in H2S (5 vol %) atmosphere at 520 C for 30 min. Experimental proof, including X-ray diffraction, Raman spectroscopy, UV-vis-NIR transmission/reflection spectra, PL spectra, and electron microscopies, is presented for the interfacial reaction between the ITO back contact and CZTS absorber. This aggressive reaction due to thermal processing contributes to substitutional diffusion of In into CZTS, formation of secondary phases and electrically conductive degradation of ITO back contact. The structural, lattice vibrational, optical absorption, and defective properties of the CZTIS alloy absorber layer have been analyzed and discussed. The new dopant In is desirably capable of improving the open circuit voltage deficit of kesterite device. However, the nonohmic back contact in the bifacial device negatively limits the open circuit voltage and fill factor, evidencing by illumination-/temperature-dependent J-V and frequency-dependent capacitance-voltage (C-V-f) measurements. A 3.4% efficient solar cell is demonstrated under simultaneously bifacial illumination from both sides of TCO front and back contacts. PMID:25340540

  17. Light trapping in thin-film solar cells measured by Raman spectroscopy

    Ledinsk, M., E-mail: ledinsky@fzu.cz [Laboratory of Nanostructures and Nanomaterials, Institute of Physics, Academy of Sciences of the Czech Republic, v. v. i., Cukrovarnick 10, 162 00 Prague (Czech Republic); Photovoltaics and Thin Film Electronics Laboratory, Institute of Microengineering (IMT), cole Polytechnique Fdrale de Lausanne (EPFL), Rue de la Maladire 71b, CH-2000 Neuchtel (Switzerland); Moulin, E.; Bugnon, G.; Meillaud, F.; Ballif, C. [Photovoltaics and Thin Film Electronics Laboratory, Institute of Microengineering (IMT), cole Polytechnique Fdrale de Lausanne (EPFL), Rue de la Maladire 71b, CH-2000 Neuchtel (Switzerland); Ganzerov, K.; Vetushka, A.; Fejfar, A. [Laboratory of Nanostructures and Nanomaterials, Institute of Physics, Academy of Sciences of the Czech Republic, v. v. i., Cukrovarnick 10, 162 00 Prague (Czech Republic)

    2014-09-15

    In this study, Raman spectroscopy is used as a tool to determine the light-trapping capability of textured ZnO front electrodes implemented in microcrystalline silicon (?c-Si:H) solar cells. Microcrystalline silicon films deposited on superstrates of various roughnesses are characterized by Raman micro-spectroscopy at excitation wavelengths of 442?nm, 514?nm, 633?nm, and 785?nm, respectively. The way to measure quantitatively and with a high level of reproducibility the Raman intensity is described in details. By varying the superstrate texture and with it the light trapping in the ?c-Si:H absorber layer, we find significant differences in the absolute Raman intensity measured in the near infrared wavelength region (where light trapping is relevant). A good agreement between the absolute Raman intensity and the external quantum efficiency of the ?c-Si:H solar cells is obtained, demonstrating the validity of the introduced method. Applications to thin-film solar cells, in general, and other optoelectronic devices are discussed.

  18. Study of detached back reflector designs for thin-film silicon solar cells

    Moulin, Etienne; Paetzold, Ulrich Wilhelm; Kirchhoff, Joachim; Bauer, Andreas; Carius, Reinhard [IEK5-Photovoltaik, Forschungszentrum Juelich GmbH (Germany)

    2012-02-15

    We present a precise and flexible method to investigate the impact of diverse detached reflector designs on the optical response of p-i-n thin-film silicon solar cells. In this study, the term detached reflectors refers to back reflectors that are separated from the silicon layers by an intermediate rear dielectric of several micrometers. Based on the utilization of a highly conductive n-doped layer and a local electrical contact scheme, the method allows the use of non-conductive rear dielectrics such as air or transparent liquids. With this approach, diverse combinations of back reflector and rear dielectric can be placed behind the same solar cell, providing a direct evaluation of their impact on the device performance. We demonstrate the positive effect of a rear dielectric of low refractive index on the light trapping and compare the performance of solar cells with an air/Ag and a standard ZnO/Ag back reflector design. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Photoluminescence properties of a-Si:H based thin films and corresponding solar cells

    Amorphous hydrogenated silicon (a-Si:H) is a well-known semiconductor with metastable properties. Direct surface exposure, as it occurs e.g. in rf plasma equipments, introduces damage due to the charged particle bombardment. The paper deals with photoluminiscence properties of virgin, oxide layer covered and chemically treated (in KCN solutions) surfaces of a-Si:H and corresponding solar cell structures. The cyanide treatment improves the electrical characteristics of MOS structures as well as solar cells. X-ray diffraction at grazing incidence and reflectance spectroscopy complete the study. The photoluminescence measurements were performed at liquid helium temperatures at 6 K using an Ar laser and lock-in signal recording device containing the PbS and Ge photodetectors. Photoluminescence bands were observed as broad luminescent peaks between 1.05-1.7 eV. Two new peaks were detected at 1.38 and 1.42 eV. The evolution of the band at ?1.2 eV related to microcrystalline silicon is investigated. The fitting and simulation of photoluminiscence spectra are presented. The surface luminescent properties of a-Si:H based structures (double layers, single thin film solar cells) before and after the passivation are compared with those of very thin oxide layers and chemically treated surfaces

  20. Back surface studies of Cu(In,Ga)Se2 thin film solar cells

    Simchi, Hamed

    Cu(In,Ga)Se2 thin film solar cells have attracted a lot of interest because they have shown the highest achieved efficiency (21%) among thin film photovoltaic materials, long-term stability, and straightforward optical bandgap engineering by changing relative amounts of present elements in the alloy. Still, there are several opportunities to further improve the performance of the Cu(In,Ga)Se2 devices. The interfaces between layers significantly affect the device performance, and knowledge of their chemical and electronic structures is essential in identifying performance limiting factors. The main goal of this research is to understand the characteristics of the Cu(In,Ga)Se2-back contact interface in order to design ohmic back contacts for Cu(In,Ga)Se2-based solar cells with a range of band gaps and device configurations. The focus is on developing either an opaque or transparent ohmic back contact via surface modification or introduction of buffer layers in the back surface. In this project, candidate back contact materials have been identified based on modeling of band alignments and surface chemical properties of the absorber layer and back contact. For the first time, MoO3 and WO 3 transparent back contacts were successfully developed for Cu(In,Ga)Se 2 solar cells. The structural, optical, and surface properties of MoO 3 and WO3 were optimized by controlling the oxygen partial pressure during reactive sputtering and post-deposition annealing. Valence band edge energies were also obtained by analysis of the XPS spectra and used to characterize the interface band offsets. As a result, it became possible to illuminate of the device from the back, resulting in a recently developed "backwall superstrate" device structure that outperforms conventional substrate Cu(In,Ga)Se2 devices in the absorber thickness range 0.1-0.5 microm. Further enhancements were achieved by introducing moderate amounts of Ag into the Cu(In,Ga)Se2 lattice during the co-evaporation method resulting in a 9.7% cell (with 0.3 microm thickness) which has the highest efficiency reported for ultrathin CIGS solar cells to date. In addition, sulfized back contacts including ITO-S and MoS 2 are compared. Interface properties of different contact layers with (Ag,Cu)(In,Ga)Se2 absorber layers with various Ga/(Ga+In) and Ag/(Ag+Cu) ratios are discussed based on the XPS analysis and thermodynamics of reactions.

  1. Process parameter impact on properties of sputtered large-area Mo bilayers for CIGS thin film solar cell applications

    Badgujar, Amol C.; Dhage, Sanjay R., E-mail: dhage@arci.res.in; Joshi, Shrikant V.

    2015-08-31

    Copper indium gallium selenide (CIGS) has emerged as a promising candidate for thin film solar cells, with efficiencies approaching those of silicon-based solar cells. To achieve optimum performance in CIGS solar cells, uniform, conductive, stress-free, well-adherent, reflective, crystalline molybdenum (Mo) thin films with preferred orientation (110) are desirable as a back contact on large area glass substrates. The present study focuses on cylindrical rotating DC magnetron sputtered bilayer Mo thin films on 300 mm × 300 mm soda lime glass (SLG) substrates. Key sputtering variables, namely power and Ar gas flow rates, were optimized to achieve best structural, electrical and optical properties. The Mo films were comprehensively characterized and found to possess high degree of thickness uniformity over large area. Best crystallinity, reflectance and sheet resistance was obtained at high sputtering powers and low argon gas flow rates, while mechanical properties like adhesion and residual stress were found to be best at low sputtering power and high argon gas flow rate, thereby indicating a need to arrive at a suitable trade-off during processing. - Highlights: • Sputtering of bilayer molybdenum thin films on soda lime glass • Large area deposition using rotating cylindrical direct current magnetron • Trade of sputter process parameters power and pressure • High uniformity of thickness and best electrical properties obtained • Suitable mechanical and optical properties of molybdenum are achieved for CIGS application.

  2. The Cu{sub 2}ZnSnSe{sub 4} thin films solar cells synthesized by electrodeposition route

    Li Ji; Ma Tuteng; Wei Ming; Liu Weifeng; Jiang Guoshun [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Zhu Changfei, E-mail: cfzhu@ustc.edu.cn [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China)

    2012-06-15

    An electrodeposition route for preparing Cu{sub 2}ZnSnSe{sub 4} thin films for thin film solar cell absorber layers is demonstrated. The Cu{sub 2}ZnSnSe{sub 4} thin films are prepared by co-electrodeposition Cu-Zn-Sn metallic precursor and subsequently annealing in element selenium atmosphere. The structure, composition and optical properties of the films were investigated by X-ray diffraction (XRD), Raman spectrometry, energy dispersive spectrometry (EDS) and UV-VIS absorption spectroscopy. The Cu{sub 2}ZnSnSe{sub 4} thin film with high crystalline quality was obtained, the band gap and absorption coefficient were 1.0 eV and 10{sup -4} cm{sup -1}, which is quite suitable for solar cells fabrication. A solar cell with the structure of ZnO:Al/i-ZnO/CdS/Cu{sub 2}ZnSnSe{sub 4}/Mo/glass was fabricated and achieved an conversion efficiency of 1.7%.

  3. Synthesis of nanostructured CuInS2 thin films and their application in dye-sensitized solar cells

    Zhao, Yu; Luo, Fazhi; Zhuang, Mixue; Liu, Zhen; Wei, Aixiang; Liu, Jun

    2016-03-01

    CuInS2 (CIS) nanostructure thin films were successfully synthesized on FTO conductive glass substrates by solvothermal method. It is found that the surface morphology and microstructure of CIS thin films can be tailored by simply adjusting the concentration of oxalic acid. CIS nanostructure films with texture of "nanosheet array" and "flower-like microsphere" were obtained and used as Pt-free counter electrode for dye-sensitized solar cells (DSSCs). The nanosheet array CIS was found to have a better electrocatalytic activity than the flower-like microsphere one. DSSCs based on nanosheet array CIS thin film counter electrode show conversion efficiency of 3.33 %, which is comparable to the Pt-catalyzed DSSCs. The easy synthesis, low cost, morphology tunable and excellent electrocatalytic property may make the CuInS2 nanostructure competitive as counter electrode in DSSCs.

  4. Investigation of blister formation in sputtered Cu2ZnSnS4 absorbers for thin film solar cells

    Blister formation in Cu2ZnSnS4 (CZTS) thin films sputtered from a quaternary compound target is investigated. While the thin film structure, composition, and substrate material are not correlated to the blister formation, a strong link between sputtering gas entrapment, in this case argon, and blistering effect is found. It is shown that argon is trapped in the film during sputtering and migrates to locally form blisters during the high temperature annealing. Blister formation in CZTS absorbers is detrimental for thin film solar cell fabrication causing partial peeling of the absorber layer and potential shunt paths in the complete device. Reduced sputtering gas entrapment, and blister formation, is seen for higher sputtering pressure, higher substrate temperature, and change of sputtering gas to larger atoms. This is all in accordance with previous publications on blister formation caused by sputtering gas entrapment in other materials

  5. Surface and interface characterization of thin-film silicon solar cell structures

    Gerlach, Dominic

    2013-02-21

    The properties of Si thin films for solar cells, the interaction with different substrates and the influence of dopants are examined with synchrotron based x-ray spectroscopy - primarily X-ray emission spectroscopy (XES) and hard X-ray photoelectron spectroscopy (HAXPES). The films are studied as-deposited (i.e., amorphous, a-Si) and after conversion into polycrystalline (poly-Si) employing solid phase crystallization (SPC). Si L{sub 2,3} XES spectra of thin-film Si samples can be described by a superposition of a-Si and monocrystalline Si-wafer (c-Si) reference spectra. According to a quantification based on that superposition principle, none of the investigated samples are completely crystallized - a measurable a-Si component always remains (5-20 %) regardless of deposition and treatment conditions. Based on additional results from electron back scattering diffraction different models are developed which may explain this finding. According to these models, the remnant a-Si component can be attributed to amorphous/disordered material at the grain boundaries. Using one of these models, the thickness of this grain-surrounding material s could be approximated to be (1.5 {+-} 0.5) nm. Further investigations of the SPC process reveal a faster crystallization for boron-doped samples, and a slower crystallization for phosphorous-doped samples, when compared to the crystallization of undoped a Si:H thin films. The peculiarities of B K XES spectra (and observed changes upon SPC) indicate that boron could act as a nucleation center promoting crystallization. Si L{sub 2,3} XES spectra of a-Si:H and P-doped poly-Si exhibit spectral features above the valence band maximum at 100 eV that could be attributed to a-Si defect states and n{sup +}-dopant states, respectively. The SPC crystallization velocity of Si thin films on ZnO:Al/glass is found to be faster than that on SiNx/glass substrate. Multiple indications for oxidization at the poly-Si/ZnO:Al interface are found based on our Si L{sub 2,3} XES analysis. Spatially resolved x-ray photoelectron spectroscopy data support this and even suggest the formation of sub-oxides or zinc silicate as an interface species. The electronic structure of the buried a-SiO{sub x}:H(B)/ZnO:Al and {mu}c-Si:H(B)/ZnO:Al interfaces are unraveled with ''depth resolved'' hard x-ray photoelectron spectroscopy. A surface band bending limited to the very surface of the silicon layers is found. The valence band maxima for the Si cover layers and the ZnO:Al TCO are determined and interface induced band bending for both interfaces are derived. At the a-SiO{sub x}:H(B)/ZnO:Al interface a tunnel barrier of (0.22 {+-} 0.31) eV and at {mu}c-Si:H(B)/ZnO:Al interface a tunnel barrier of (-0.08 {+-} 0.31) eV is determined. This explains a previously empirically found solar cell efficiency increase produced by introducing a {mu}c-Si:H(B) buffer layer between an a-Si p-i-n cell and the ZnO:Al/glass substrate.

  6. Transparent conducting oxide contacts and textured metal back reflectors for thin film silicon solar cells

    Franken, R.H.-J.

    2006-01-01

    With the growing population and the increasing environmental problems of the 'common' fossil and nuclear energy production, the need for clean and sustainable energy sources is evident. Solar energy conversion, such as in photovoltaic (PV) systems, can play a major role in the urgently needed energy transition in electricity production. At the present time PV module production is dominated by the crystalline wafer technology. Thin film silicon technology is an alternative solar energy technol...

  7. Interface properties of Cd-free buffer layers on on CIGSe thin film solar cells

    Theisen, J.P.; Erfurth, F.; Weinhardt, L. [University of Wuerzburg (Germany). Experimental Physics VII; Duarte, R.; Baer, M. [Helmholtz Institut, Berlin (Germany); Niesen, T.; Palm, J. [Avancis GmbH, Muenchen (Germany); Barreau, N.; Couzinie-Devy, F.; Kessler, J. [Institut des Materiaux, Nantes (France); Reinert, F. [University of Wuerzburg (Germany). Experimental Physics VII; Forschungszentrum Karlsruhe GmbH (Germany). Gemeinschaftslabor fuer Nanoanalytik

    2010-07-01

    In order to replace the toxic Cadmium, the substitution of the CdS buffer layer in thin film solar cells based on Cu(In,Ga)(S,Se){sub 2} (CIGSSe) is of great interest. Alternative buffer layers like (In,Al){sub 2}S{sub 3}, In{sub 2}S{sub 3}, or (Zn{sub 1-x},Mg{sub x})O deposited by conventional sputter and chemical bath deposition techniques, have shown efficiencies close to or comparable to those of CdS containing solar cells. To understand the chemical and electronic properties of these buffer layers and its influence on the absorber, we studied the buffer-absorber interface using photoelectron spectroscopy (XPS, UPS) and inverse photoelectron spectroscopy (IPES). The combination of these non-destructive techniques provides detailed information about the chemical properties of the studied surface, as well as can be used for a direct determination of the conduction and valence band alignment at the heterojunction. Band-gap values at the surface as derived by UPS and IPES are also verified by electron energy loss spectroscopy (EELS). The results are discussed in conjunction with the respective cell parameters.

  8. Interface properties of Cd-free buffer layers on on CIGSe thin film solar cells

    In order to replace the toxic Cadmium, the substitution of the CdS buffer layer in thin film solar cells based on Cu(In,Ga)(S,Se)2 (CIGSSe) is of great interest. Alternative buffer layers like (In,Al)2S3, In2S3, or (Zn1-x,Mgx)O deposited by conventional sputter and chemical bath deposition techniques, have shown efficiencies close to or comparable to those of CdS containing solar cells. To understand the chemical and electronic properties of these buffer layers and its influence on the absorber, we studied the buffer-absorber interface using photoelectron spectroscopy (XPS, UPS) and inverse photoelectron spectroscopy (IPES). The combination of these non-destructive techniques provides detailed information about the chemical properties of the studied surface, as well as can be used for a direct determination of the conduction and valence band alignment at the heterojunction. Band-gap values at the surface as derived by UPS and IPES are also verified by electron energy loss spectroscopy (EELS). The results are discussed in conjunction with the respective cell parameters.

  9. AgSb(SxSe1−x)2 thin films for solar cell applications

    Highlights: ► AgSb(SxSe1−x)2 thin films were formed by heating Na2SeSO3 dipped Sb2S3/Ag layers. ► S/Se ratio was varied by changing the dipping time in Na2SeSO3 solution. ► Characterized the films using XRD, XPS, SEM, Optical and electrical measurements. ► Band gap engineering of 1−1.1 eV for x = 0.51 and 0.52 respectively. ► PV Glass/FTO/CdS/AgSb(SxSe1−x)2/C were prepared showing Voc = 410 mV, Jsc = 5.7 mA/cm2. - Abstract: Silver antimony sulfoselenide (AgSb(SxSe1−x)2) thin films were prepared by heating glass/Sb2S3/Ag layers after selenization using sodium selenosulphate solution. First, Sb2S3 thin films were deposited on glass substrates from a chemical bath containing SbCl3 and Na2S2O3. Then Ag thin films were thermally evaporated onto glass/Sb2S3, followed by selenization by dipping in an acidic solution of Na2SeSO3. The duration of selenium dipping was varied as 30 min and 2 h. The heating condition was at 350 °C for 1 h in vacuum. Analysis of X-ray diffraction pattern of the thin films formed after heating showed the formation of AgSb(SxSe1−x)2. Morphology and elemental analysis were done by scanning electron microscopy and energy dispersive X-ray detection. Depth profile of composition of the thin films was performed by X-ray Photoelectron Spectroscopy. The spectral study showed the presence of Ag, Sb, S, and Se, and the corresponding binding energy analysis confirmed the formation of AgSb(SxSe1−x)2. Photovoltaic structures (PV) were prepared using AgSb(SxSe1−x)2 thin films as absorber and CdS thin films as window layers on FTO coated glass substrates. The PV structures were heated at 60–80 °C in air for 1 h to improve ohmic contact. Analysis of J–V characteristics of the PV structures showed Voc from 230 to 490 mV and Jsc 0.28 to 5.70 mA/cm2, under illumination of AM1.5 radiation using a solar simulator

  10. Hybrid ZnO nanowire/a-Si:H thin-film radial junction solar cells using nanoparticle front contacts

    Hydrothermally synthesized disordered ZnO nanowires were conformally coated with a-Si:H thin-films to fabricate three dimensional hybrid nanowire/thin-film structures. The a-Si:H layer formed a radial junction p-i-n diode solar cell around the ZnO nanowire. The cylindrical hybrid solar cells enhanced light scattering throughout the UV-visible-NIR spectrum (300 nm–800 nm) resulting in a 22% increase in short-circuit current density compared to the reference planar p-i-n device. A fill factor of 69% and a total power conversion efficiency of 6.5% were achieved with the hybrid nanowire solar cells using a spin-on indium tin oxide nanoparticle suspension as the top contact

  11. Light trapping and electrical transport in thin-film solar cells with randomly rough textures

    Kowalczewski, Piotr; Bozzola, Angelo; Liscidini, Marco; Claudio Andreani, Lucio

    2014-05-01

    Using rigorous electro-optical calculations, we predict a significant efficiency enhancement in thin-film crystalline silicon (c-Si) solar cells with rough interfaces. We show that an optimized rough texture allows one to reach the Lambertian limit of absorption in a wide absorber thickness range from 1 to 100 μm. The improvement of efficiency due to the roughness is particularly substantial for thin cells, for which light trapping is crucial. We consider Auger, Shockley-Read-Hall (SRH), and surface recombination, quantifying the importance of specific loss mechanisms. When the cell performance is limited by intrinsic Auger recombination, the efficiency of 24.4% corresponding to the wafer-based PERL cell can be achieved even if the absorber thickness is reduced from 260 to 10 μm. For cells with material imperfections, defect-based SRH recombination contributes to the opposite trends of short-circuit current and open-circuit voltage as a function of the absorber thickness. By investigating a wide range of SRH parameters, we determine an optimal absorber thickness as a function of material quality. Finally, we show that the efficiency enhancement in textured cells persists also in the presence of surface recombination. Indeed, in our design the efficiency is limited by recombination at the rear (silicon absorber/back reflector) interface, and therefore it is possible to engineer the front surface to a large extent without compromising on efficiency.

  12. Comparison of silicon oxide and silicon carbide absorber materials in silicon thin-film solar cells

    Walder, Cordula; Kellermann, Martin; Wendler, Elke; Rensberg, Jura; von Maydell, Karsten; Agert, Carsten

    2015-02-01

    Since solar energy conversion by photovoltaics is most efficient for photon energies at the bandgap of the absorbing material the idea of combining absorber layers with different bandgaps in a multijunction cell has become popular. In silicon thin-film photovoltaics a multijunction stack with more than two subcells requires a high bandgap amorphous silicon alloy top cell absorber to achieve an optimal bandgap combination. We address the question whether amorphous silicon carbide (a-SiC:H) or amorphous silicon oxide (a-SiO:H) is more suited for this type of top cell absorber. Our single cell results show a better performance of amorphous silicon carbide with respect to fill factor and especially open circuit voltage at equivalent Tauc bandgaps. The microstructure factor of single layers indicates less void structure in amorphous silicon carbide than in amorphous silicon oxide. Yet photoconductivity of silicon oxide films seems to be higher which could be explained by the material being not truly intrinsic. On the other hand better cell performance of amorphous silicon carbide absorber layers might be connected to better hole transport in the cell.

  13. Comparison of silicon oxide and silicon carbide absorber materials in silicon thin-film solar cells

    Walder Cordula

    2015-01-01

    Full Text Available Since solar energy conversion by photovoltaics is most efficient for photon energies at the bandgap of the absorbing material the idea of combining absorber layers with different bandgaps in a multijunction cell has become popular. In silicon thin-film photovoltaics a multijunction stack with more than two subcells requires a high bandgap amorphous silicon alloy top cell absorber to achieve an optimal bandgap combination. We address the question whether amorphous silicon carbide (a-SiC:H or amorphous silicon oxide (a-SiO:H is more suited for this type of top cell absorber. Our single cell results show a better performance of amorphous silicon carbide with respect to fill factor and especially open circuit voltage at equivalent Tauc bandgaps. The microstructure factor of single layers indicates less void structure in amorphous silicon carbide than in amorphous silicon oxide. Yet photoconductivity of silicon oxide films seems to be higher which could be explained by the material being not truly intrinsic. On the other hand better cell performance of amorphous silicon carbide absorber layers might be connected to better hole transport in the cell.

  14. Effect of substrate position in i-ZnO thin-film formation to Cu(In,Ga)Se2 solar cell

    Intrinsic ZnO (i-ZnO) thin films were prepared by rf magnetron sputtering of nondoped ZnO targets in Ar gas under various substrate positions and they were applied to solar cells. We have characterized i-ZnO thin films and investigated the solar cell performance. The resistivity and the full width at half maximum (FWHM) in the x-ray diffraction peak were changed, depending on the substrate position. The performance of solar cells was correspondent to the change of the resistivity and the FWHM of the i-ZnO thin films

  15. Nanostructured thin film silicon solar cells efficiency improvement using gold nanoparticles

    Pudasaini, Pushpa Raj; Ayon, Arturo A. [MEMS Research Lab., Department of Physics and Astronomy, University of Texas at San Antonio, TX 78249 (United States)

    2012-08-15

    We report the computational modeling of localized surface plasmon effects arising on gold (Au) nanoparticles deposited on silicon nanohole (SiNH) textured surface for thin film silicon solar cells application. Detailed balance analysis is carried out for the limiting efficiency of an optimized SiNH array textured surface in combination with the surface and bottom-of-a-trench Au nanoparticle array described herein. We found that for the proposed geometry of the solar cell, the short circuit current density (J{sub SC}) and the power conversion efficiency (PCE) are 31.57 mA/cm{sup 2} and 25.42%, respectively, that compare favorably to the predicted J{sub SC} and PCE values of 25.45 mA/cm{sup 2} and 20.87% for an optimized SiNH textured surface without Au nanoparticles. We optimized the silicon dioxide/silicon nitride (SiO{sub 2}/Si{sub 3}N{sub 4}) stack as a passivation layer, retaining the higher optical absorption. The scattering of incident radiation by the Au nanoparticles near their localized plasmon resonance is responsible for higher optical absorption and hence the higher predicted values for J{sub SC} and PCE. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Low temperature (< 100 deg. C) fabrication of thin film silicon solar cells by HWCVD

    Amorphous silicon films have been made by HWCVD at a very low substrate temperature of ? 100 deg. C (in a dynamic substrate heating mode) without artificial substrate cooling, through a substantial increase of the filament-substrate distance (? 80 mm) and using one straight tantalum filament. The material is made at a reasonable deposition rate of 0.11 nm/s. Optimized films made this way have device quality, as confirmed by the photosensitivity of > 105. Furthermore, they possess a low structural disorder, manifested by the small ?/2 value (half width at half maximum) of the transverse optic (TO) Si-Si vibration peak (at 480 cm-1) in the Raman spectrum of ? 30.4 cm-1, which translates into a bond angle variation of only ? 6.4 deg. The evidence gathered from the studies on the structure of the HWCVD grown film by three different techniques, Raman spectroscopy, spectroscopic ellipsometry and transmission electron microscopy, indicate that we have been able to make a photosensitive material with a structural disorder that is smaller than that expected at such a low deposition temperature. Tested in a p-i-n solar cell on Asahi SnO2:F coated glass (without ZnO at the back reflector), this i-layer gave an efficiency of 3.4%. To our knowledge, this is the first report of a HWCVD thin film silicon solar cell made at such a low temperature

  17. Comparative investigation of solar cell thin film processing using nanosecond and femtosecond lasers

    The purpose of the present study was to examine the possibility of laser-machining of CuInSe2-based photovoltaic devices. Therefore, ablation thresholds and ablation rates of ZnO, CuInSe2 and Mo thin films have been measured for irradiation with nanosecond laser pulses of ultraviolet and visible light and subpicosecond laser pulses of a Ti : sapphire laser. The experimental results were compared with the theoretical evaluation of the samples heat regime obtained from numerical calculations. In addition, the photo-electrical properties of the solar cells were measured before and after laser-machining. Scanning electron microscopy and energy dispersive x-ray analyses were employed to characterize the laser-induced ablation channels. As a result, two phenomena were found to limit the laser-machining process: (i) residues of Mo that were projected onto the walls of the ablation channel and (ii) the metallization of the CuInSe2 semiconductor close to the channel. Both effects lead to a shunt in the device that decreases the photovoltaic efficiency. As a consequence of these limiting effects, micromachining of CuInSe2-based solar cells was not possible with nanosecond laser pulses. Only subpicosecond laser pulses provided selective or complete ablation of the thin layers without a relevant change in the photoelectrical properties

  18. Diode laser crystallization processes of Si thin-film solar cells on glass

    Yun Jae Sung

    2014-07-01

    Full Text Available The crystallization of Si thin-film on glass using continuous-wave diode laser is performed. The effect of various processing parameters including laser power density and scanning speed is investigated in respect to microstructure and crystallographic orientation. Optimal laser power as per scanning speed is required in order to completely melt the entire Si film. When scan speed of 15–100 cm/min is used, large linear grains are formed along the laser scan direction. Laser scan speed over 100 cm/min forms relatively smaller grains that are titled away from the scan direction. Two diode model fitting of Suns-Voc results have shown that solar cells crystallized with scan speed over 100 cm/min are limited by grain boundary recombination (n = 2. EBSD micrograph shows that the most dominant misorientation angle is 60°. Also, there were regions containing high density of twin boundaries up to ~1.2 × 10-8/cm2. SiOx capping layer is found to be effective for reducing the required laser power density, as well as changing preferred orientation of the film from ⟨ 110 ⟩ to ⟨ 100 ⟩ in surface normal direction. Cracks are always formed during the crystallization process and found to be reducing solar cell performance significantly.

  19. Diode laser crystallization processes of Si thin-film solar cells on glass

    Yun, Jae Sung; Ahn, Cha Ho; Jung, Miga; Huang, Jialiang; Kim, Kyung Hun; Varlamov, Sergey; Green, Martin A.

    2014-07-01

    The crystallization of Si thin-film on glass using continuous-wave diode laser is performed. The effect of various processing parameters including laser power density and scanning speed is investigated in respect to microstructure and crystallographic orientation. Optimal laser power as per scanning speed is required in order to completely melt the entire Si film. When scan speed of 15-100 cm/min is used, large linear grains are formed along the laser scan direction. Laser scan speed over 100 cm/min forms relatively smaller grains that are titled away from the scan direction. Two diode model fitting of Suns-Voc results have shown that solar cells crystallized with scan speed over 100 cm/min are limited by grain boundary recombination (n = 2). EBSD micrograph shows that the most dominant misorientation angle is 60°. Also, there were regions containing high density of twin boundaries up to ~1.2 × 10-8/cm2. SiOx capping layer is found to be effective for reducing the required laser power density, as well as changing preferred orientation of the film from ⟨ 110 ⟩ to ⟨ 100 ⟩ in surface normal direction. Cracks are always formed during the crystallization process and found to be reducing solar cell performance significantly.

  20. The complex interface chemistry of thin-film silicon/zinc oxide solar cell structures.

    Gerlach, D; Wimmer, M; Wilks, R G; Flix, R; Kronast, F; Ruske, F; Br, M

    2014-12-21

    The interface between solid-phase crystallized phosphorous-doped polycrystalline silicon (poly-Si(n(+))) and aluminum-doped zinc oxide (ZnO:Al) was investigated using spatially resolved photoelectron emission microscopy. We find the accumulation of aluminum in the proximity of the interface. Based on a detailed photoemission line analysis, we also suggest the formation of an interface species. Silicon suboxide and/or dehydrated hemimorphite have been identified as likely candidates. For each scenario a detailed chemical reaction pathway is suggested. The chemical instability of the poly-Si(n(+))/ZnO:Al interface is explained by the fact that SiO2 is more stable than ZnO and/or that H2 is released from the initially deposited a-Si:H during the crystallization process. As a result, Zn (a deep acceptor in silicon) is "liberated" close to the silicon/zinc oxide interface presenting the inherent risk of forming deep defects in the silicon absorber. These could act as recombination centers and thus limit the performance of silicon/zinc oxide based solar cells. Based on this insight some recommendations with respect to solar cell design, material selection, and process parameters are given for further knowledge-based thin-film silicon device optimization. PMID:25363298

  1. InGaN-based thin film solar cells: Epitaxy, structural design, and photovoltaic properties

    InxGa1−xN, with the tunable direct bandgaps from ultraviolet to near infrared region, offers a promising candidate for the high-efficiency next-generation thin-film photovoltaic applications. Although the adoption of thick InGaN film as the active region is desirable to obtain efficient light absorption and carrier collection compared to InGaN/GaN quantum wells structure, the understanding on the effect from structural design is still unclear due to the poor-quality InGaN films with thickness and difficulty of p-type doping. In this paper, we comprehensively investigate the effects from film epitaxy, doping, and device structural design on the performances of the InGaN-based solar cells. The high-quality InGaN thick film is obtained on AlN/sapphire template, and p-In0.08Ga0.92N is achieved with a high hole concentration of more than 1018 cm−3. The dependence of the photovoltaic performances on different structures, such as active regions and p-type regions is analyzed with respect to the carrier transport mechanism in the dark and under illumination. The strategy of improving the p-i interface by using a super-thin AlN interlayer is provided, which successfully enhances the performance of the solar cells

  2. Transition metal oxide window layer in thin film amorphous silicon solar cells

    Pin-type hydrogenated amorphous silicon solar cells have been fabricated by replacing state of the art silicon based window layer with more transparent transition metal oxide (TMO) materials. Three kinds of TMOs: vanadium oxide, tungsten oxide, and molybdenum oxide (MoOx) were comparatively investigated to reveal the design principles of metal oxide window layers. It was found that MoOx exhibited the best performance due to its higher work function property compared to other materials. In addition, the band alignment between MoOx and amorphous Si controls the series resistance, which was verified through compositional variation of MoOx thin films. The design principles of TMO window layer in amorphous Si solar cells are summarized as follows: A wide optical bandgap larger than 3.0 eV, a high work function larger than 5.2 eV, and a band alignment condition rendering efficient hole collection from amorphous Si absorber layer. - Highlights: • High work function metal oxides can potentially replace the conventional p-a-SiC. • V2Ox, WOx, and MoOx are comparatively investigated in this study. • MoOx is the most relevant material due to its highest work function. • Slightly oxygen deficient MoOx exhibited performance enhancement at x = 2.9

  3. Design, fabrication and optical characterization of photonic crystal assisted thin film monocrystalline-silicon solar cells.

    Meng, Xianqin; Depauw, Valérie; Gomard, Guillaume; El Daif, Ounsi; Trompoukis, Christos; Drouard, Emmanuel; Jamois, Cécile; Fave, Alain; Dross, Frédéric; Gordon, Ivan; Seassal, Christian

    2012-07-01

    In this paper, we present the integration of an absorbing photonic crystal within a monocrystalline silicon thin film photovoltaic stack fabricated without epitaxy. Finite difference time domain optical simulations are performed in order to design one- and two-dimensional photonic crystals to assist crystalline silicon solar cells. The simulations show that the 1D and 2D patterned solar cell stacks would have an increased integrated absorption in the crystalline silicon layer would increase of respectively 38% and 50%, when compared to a similar but unpatterned stack, in the whole wavelength range between 300 nm and 1100 nm. In order to fabricate such patterned stacks, we developed an effective set of processes based on laser holographic lithography, reactive ion etching and inductively coupled plasma etching. Optical measurements performed on the patterned stacks highlight the significant absorption increase achieved in the whole wavelength range of interest, as expected by simulation. Moreover, we show that with this design, the angle of incidence has almost no influence on the absorption for angles as high as around 60°. PMID:22828615

  4. Transition metal oxide window layer in thin film amorphous silicon solar cells

    Fang, Liang [Department of Electrical Engineering, Tianjin Institute of Power Source, 6 Huakeqi Rd., Hi-tech Industrial Park, Tianjin 300384 (China); Baik, Seung Jae, E-mail: sjbaik@hknu.ac.kr [Department of Electrical, Electronic, and Control Engineering, Hankyong National University, 327 Jungang-ro, Anseong-si, Gyeonggi-do 456-749 (Korea, Republic of); Lim, Koeng Su [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon 305-701 (Korea, Republic of)

    2014-04-01

    Pin-type hydrogenated amorphous silicon solar cells have been fabricated by replacing state of the art silicon based window layer with more transparent transition metal oxide (TMO) materials. Three kinds of TMOs: vanadium oxide, tungsten oxide, and molybdenum oxide (MoO{sub x}) were comparatively investigated to reveal the design principles of metal oxide window layers. It was found that MoO{sub x} exhibited the best performance due to its higher work function property compared to other materials. In addition, the band alignment between MoO{sub x} and amorphous Si controls the series resistance, which was verified through compositional variation of MoO{sub x} thin films. The design principles of TMO window layer in amorphous Si solar cells are summarized as follows: A wide optical bandgap larger than 3.0 eV, a high work function larger than 5.2 eV, and a band alignment condition rendering efficient hole collection from amorphous Si absorber layer. - Highlights: High work function metal oxides can potentially replace the conventional p-a-SiC. V{sub 2}O{sub x}, WO{sub x}, and MoO{sub x} are comparatively investigated in this study. MoO{sub x} is the most relevant material due to its highest work function. Slightly oxygen deficient MoO{sub x} exhibited performance enhancement at x = 2.9.

  5. Fabrication of CZTS-based thin film solar cells using all-solution processing and pulsed light crystallization

    Munn, Carson; Haran, Shivan; Seok, Ilwoo

    2013-04-01

    Solar cells can be produced using thin film based photovoltaic materials; these are highly efficient with respect to their optical properties and manufacturing cost. The prospective thin film solar cells are composed of Copper, Zinc, Tin, and Sulfide, or `CZTS', this contains chemicals, which are both earth-abundant and non-toxic. The all-solution based process is investigated which is on a single-step electro-chemistry deposition that provides all constituents from the same electrolyte. This investigation was successful in our research group with a high degree of success and a photo-thermal energy driven sintering process that forms a CZTS material from the as-deposited chemicals was added. This enables the as-deposited chemicals to be covalently bonded and crystallized without using a costly vacuum process. In post-heat treatment, a homemade intense pulsed lighting (IPL) system was utilized for rapid thermal annealing. The successful deposition of the CZTS thin film was then evaluated and analyzed using cyclic voltammetry (CV), SEM/EDAX, and XRD. It has been concluded that photovoltaic thin film fabrication is truly comparable to the conventional deposition and annealing methods in terms of photovoltaic efficiency and cost-effectiveness.

  6. Defect engineering in solar cell manufacturing and thin film solar cell development

    Sopori, B.L. [National Renewable Energy Lab., Golden, CO (United States)

    1995-08-01

    During the last few years many defect engineering concepts were successfully applied to fabricate high efficiency silicon solar cells on low-cost substrates. Some of the research advances are described.

  7. Thin-film silicon triple-junction solar cell with 12.5% stable efficiency on innovative flat light-scattering substrate

    Sderstrm, Karin; Bugnon, Grgory; Biron, Re?mi; Pahud, Ce?line; Meillaud, Fanny; Haug, Franz-Josef; Ballif, Christophe

    2012-01-01

    Several thin-film solar cell technologies require light-trapping schemes that are predominantly based on depositing the solar cells on rough surfaces. While this approach efficiently increases the density of photo-generated carriers, open-circuit voltage and fill factor generally decrease. Substrates that decouple the growth interface from the light-scattering interface were previously proposed as a solution to this dilemma, and proof-of-concepts were demonstrated in thin film-silicon solar c...

  8. Applications of microcrystalline hydrogenated cubic silicon carbide for amorphous silicon thin film solar cells

    We demonstrated the fabrication of n-i-p type amorphous silicon (a-Si:H) thin film solar cells using phosphorus doped microcrystalline cubic silicon carbide (?c-3C-SiC:H) films as a window layer. The Hot-wire CVD method and a covering technique of titanium dioxide TiO2 on TCO was utilized for the cell fabrication. The cell configuration is TCO/TiO2/n-type ?c-3C-SiC:H/intrinsic a-Si:H/p-type ?c- SiCx (a-SiCx:H including ?c-Si:H phase)/Al. Approximately 4.5% efficiency with a Voc of 0.953 V was obtained for AM-1.5 light irradiation. We also prepared a cell with the undoped a-Si1-xCx:H film as a buffer layer to improve the n/i interface. A maximum Voc of 0.966 V was obtained

  9. Fabrication of CdS/CdTe-Based Thin Film Solar Cells Using an Electrochemical Technique

    I. M. Dharmadasa

    2014-06-01

    Full Text Available Thin film solar cells based on cadmium telluride (CdTe are complex devices which have great potential for achieving high conversion efficiencies. Lack of understanding in materials issues and device physics slows down the rapid progress of these devices. This paper combines relevant results from the literature with new results from a research programme based on electro-plated CdS and CdTe. A wide range of analytical techniques was used to investigate the materials and device structures. It has been experimentally found that n-, i- and p-type CdTe can be grown easily by electroplating. These material layers consist of nano- and micro-rod type or columnar type grains, growing normal to the substrate. Stoichiometric materials exhibit the highest crystallinity and resistivity, and layers grown closer to these conditions show n → p or p → n conversion upon heat treatment. The general trend of CdCl2 treatment is to gradually change the CdTe material’s n-type electrical property towards i-type or p-type conduction. This work also identifies a rapid structural transition of CdTe layer at 385 ± 5 °C and a slow structural transition at higher temperatures when annealed or grown at high temperature. The second transition occurs after 430 °C and requires more work to understand this gradual transition. This work also identifies the existence of two different solar cell configurations for CdS/CdTe which creates a complex situation. Finally, the paper presents the way forward with next generation CdTe-based solar cells utilising low-cost materials in their columnar nature in graded bandgap structures. These devices could absorb UV, visible and IR radiation from the solar spectrum and combine impact ionisation and impurity photovoltaic (PV effect as well as making use of IR photons from the surroundings when fully optimised.

  10. Antimony sulphide thin film as an absorber in chemically deposited solar cells

    Antimony sulfide thin films (thickness, 500 nm) were deposited on chemically deposited CdS thin films (100 nm) obtained on 3 mm glass substrates coated with a transparent conductive coating of SnO2:F (TEC-15 with 15 Ω sheet resistance). Two different chemical formulations were used for depositing antimony sulfide films. These contained (i) antimony trichloride dissolved in acetone and sodium thiosulfate, and (ii) potassium antimony tartrate, triethanolamine, ammonia, thioacetamide and small concentrations of silicotungstic acid. The films were heated at 250 deg. C in nitrogen. The cell structure was completed by depositing a 200 nm p-type PbS thin film. Graphite paint applied on the PbS thin film and a subsequent layer of silver paint served as the p-side contact. The cell structure: SnO2:F/CdS/Sb2S3 (i or ii)/PbS showed open circuit voltage (Voc) of 640 mV and short circuit current density (Jsc) above 1 mA cm-2 under 1 kW m-2 tungsten-halogen radiation. Four cells, each of 1.7 cm2 area, were series-connected to give Voc of 1.6 V and a short circuit current of 4.1 mA under sunlight (1060 W m-2)

  11. Antimony sulphide thin film as an absorber in chemically deposited solar cells

    Messina, Sarah; Nair, M T S; Nair, P K [Department of Solar Energy Materials, Centro de Investigacion en EnergIa, Universidad Nacional Autonoma de Mexico, Temixco, Morelos-62580 (Mexico)

    2008-05-07

    Antimony sulfide thin films (thickness, 500 nm) were deposited on chemically deposited CdS thin films (100 nm) obtained on 3 mm glass substrates coated with a transparent conductive coating of SnO{sub 2}:F (TEC-15 with 15 {omega} sheet resistance). Two different chemical formulations were used for depositing antimony sulfide films. These contained (i) antimony trichloride dissolved in acetone and sodium thiosulfate, and (ii) potassium antimony tartrate, triethanolamine, ammonia, thioacetamide and small concentrations of silicotungstic acid. The films were heated at 250 deg. C in nitrogen. The cell structure was completed by depositing a 200 nm p-type PbS thin film. Graphite paint applied on the PbS thin film and a subsequent layer of silver paint served as the p-side contact. The cell structure: SnO{sub 2}:F/CdS/Sb{sub 2}S{sub 3} (i or ii)/PbS showed open circuit voltage (V{sub oc}) of 640 mV and short circuit current density (J{sub sc}) above 1 mA cm{sup -2} under 1 kW m{sup -2} tungsten-halogen radiation. Four cells, each of 1.7 cm{sup 2} area, were series-connected to give V{sub oc} of 1.6 V and a short circuit current of 4.1 mA under sunlight (1060 W m{sup -2})

  12. Antimony sulphide thin film as an absorber in chemically deposited solar cells

    Messina, Sarah; Nair, M. T. S.; Nair, P. K.

    2008-05-01

    Antimony sulfide thin films (thickness, 500 nm) were deposited on chemically deposited CdS thin films (100 nm) obtained on 3 mm glass substrates coated with a transparent conductive coating of SnO2:F (TEC-15 with 15 Ω sheet resistance). Two different chemical formulations were used for depositing antimony sulfide films. These contained (i) antimony trichloride dissolved in acetone and sodium thiosulfate, and (ii) potassium antimony tartrate, triethanolamine, ammonia, thioacetamide and small concentrations of silicotungstic acid. The films were heated at 250 °C in nitrogen. The cell structure was completed by depositing a 200 nm p-type PbS thin film. Graphite paint applied on the PbS thin film and a subsequent layer of silver paint served as the p-side contact. The cell structure: SnO2:F/CdS/Sb2S3 (i or ii)/PbS showed open circuit voltage (Voc) of 640 mV and short circuit current density (Jsc) above 1 mA cm-2 under 1 kW m-2 tungsten-halogen radiation. Four cells, each of 1.7 cm2 area, were series-connected to give Voc of 1.6 V and a short circuit current of 4.1 mA under sunlight (1060 W m-2).

  13. Directly patterned TiO2 nanostructures for efficient light harvesting in thin film solar cells

    Ram, Sanjay K.; Rizzoli, Rita; Desta, Derese; Jeppesen, Bjarke R.; Bellettato, Michele; Samatov, Ivan; Tsao, Yao-Chung; Johannsen, Sabrina R.; Neuvonen, Pekka T.; Pedersen, Thomas Garm; Pereira, Rui N.; Pedersen, Kjeld; Balling, Peter; Nylandsted Larsen, Arne

    2015-09-01

    A novel, scalable, and low-cost strategy for fabricating sub-wavelength scale hierarchical nanostructures by direct patterning of TiO2 nanoparticles on glass substrates is reported. Two nanostructural designs of light-trapping back-surface reflectors (BSR) have been fabricated for increasing the photon-harvesting properties of thin-film solar cells: a quasi-periodic nano-crater design and a random nano-bump design. The efficient light-scattering properties of the nano-crater design over a broad wavelength range are demonstrated by the measured haze factor being larger than 40% at wavelengths (~700 nm) near the band edge of amorphous silicon (a-Si:H). The a-Si:H-based n-i-p solar cell fabricated with an only ~200 nm thick absorber layer on the nano-crater BSR shows a short-circuit current density (J sc) of ~16.1 mA cm-2 representing a 28% enhancement compared to the cell deposited on a non-textured flat substrate. Measurements of the external quantum efficiency of the cell fabricated on the quasi-periodic nano-crater surface at long wavelengths, λ  >  700 nm, demonstrate an increase of a factor of 5 relative to that of a flat reference solar cell. The theoretical modeling results of optical absorption corroborate well with the experimental findings and are used to identify the volumes of strong optical absorption in the a-Si:H active layer of the textured BSR devices.

  14. Fabrication and characterization of highly efficient thin-film polycrystalline-silicon solar cells based on aluminium-induced crystallization

    Thin-film polycrystalline-silicon solar cells might become an alternative to bulk silicon solar cells if sufficiently high efficiencies can be obtained. In this work we made pc-Si layers using aluminium-induced crystallization and thermal CVD on alumina substrates. By using plasma texturing and optimizing the cell structure, we increased the current density of our cells and achieved a cell efficiency of 8.0%. At present, our cell efficiency seems to be mainly limited by the presence in our layers of a high density of electronically active intragrain defects. Intragrain quality improvement will therefore be very important to further increase our pc-Si cell efficiency

  15. Preparation of thin films, with base to precursor materials of type Cu-In-Se elaborated by electrodeposition for the solar cells elaboration

    Thin films of chalcogenide compounds are promising because they have excellent optoelectronic characteristics to be applied in solar cells. In particular, CuInSe2 and Cd Te thin films have shown high solar to electrical conversion efficiency. However, this efficiency is limited by the method of preparation, in this case, physical vapor deposition techniques are used. In order to increase the area of deposition t is necessary to use chemical methods, for example, electrodeposition technique. In this paper, the preparation of Cu-In-Se precursors thin films by electrochemical method is reported. These precursors were used to build solar cells with 7.9 % of efficiency. (Author)

  16. Optimized Packing Density of Large CZTS Nanoparticles Synthesized by Hot-injection for Thin Film Solar Cells.

    Engberg, Sara Lena Josefin; Lam, Yeng Ming; Schou, Jrgen

    2015-01-01

    The absorbing kesterite material, Cu2ZnSn(SxSe1-x)4 (CZTS), is very promising for future thin film solar cells. The material is non-toxic, the elements abundant, and it has a high absorption coefficient. These properties make CZTS a potential candidate also for large-scale applications. Here, solution processing allows for comparatively fast and inexpensive fabrication, and also holds the record efficiency in the kesterite family. Unfortunately, the record cell is deposited with a highly toxi...

  17. A rational elemental-directed alcohol-thermal route to CdSe nanostructures for thin film solar cells

    We have reported an alcohol-thermal method to in-situ synthesis of Cadmium Selenide (CdSe) nanocrystals/thin films on Cd/indium-doped tin oxide (ITO) substrates through a direct reaction of Se and Cd. In the synthetic system, ligands and surfactants are not introduced, and concentration of reaction precursors is not high, thus not only it is a very economic and environmental-friendly route, but also the CdSe film without any impurities is obtained. The Cd deposited on ITO substrates by magnetron sputtering acted as dual roles: reactant source and hard template for the final product. The microstructure is analyzed by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). Poly(3-hexylthiophene) (P3HT) is deposited on CdSe film to fabricate a hybrid thin film solar cell device with ITO/CdSe/P3HT/Al structure to demonstrate solar light to electrical energy conversion. - Highlights: • CdSe nanocrystals/thin films were fabricated by an easy alcohol-thermal approach. • The method requires no ligands, high concentration of precursors or surfactants. • The photovoltaic device was based on the hybrid thin film of CdSe NCs and P3HT composites

  18. Studies of compositional dependent CZTS thin film solar cells by pulsed laser deposition technique: An attempt to improve the efficiency

    Moholkar, A.V., E-mail: avmoholkar@yahoo.co.in [Electrochemical Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, Maharashtra (India); Shinde, S.S. [Electrochemical Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, Maharashtra (India); Agawane, G.L.; Jo, S.H. [Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-Dong, Puk-Gu, Gwangju 500 757 (Korea, Republic of); Rajpure, K.Y. [Electrochemical Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, Maharashtra (India); Patil, P.S. [Thin Film Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, Maharashtra (India); Bhosale, C.H. [Electrochemical Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, Maharashtra (India); Kim, J.H., E-mail: jinhyeok@chonnam.ac.kr [Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-Dong, Puk-Gu, Gwangju 500 757 (Korea, Republic of)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Synthesis of CZTS thin films by PLD. Black-Right-Pointing-Pointer Effect of stoichiometry, its deviation on the physical properties. Black-Right-Pointing-Pointer Improvement in conversion efficiency using CZTS absorber layer. - Abstract: The performance of CZTS thin films deposited by using pulsed laser deposition technique is investigated as a function of target composition. The chemical composition ratio a = Cu/(Zn + Sn) of the target material has been varied from 0.8 to 1.2 in step of 0.1 by keeping Zn/Sn constant. The effect of the chemical composition in the precursor thin films on the structural, morphological, chemical and optical properties of the CZTS thin films has been investigated. X-ray diffraction and X-ray photoelectron spectroscopy studies showed that the annealed CZTS thin films are of a single kesterite crystal structure without any other secondary phases. The direct band gap energy of the CZTS thin films is found to decrease from 1.72-1.53 eV with increase of 'a'. The estimated band-gap energy from the quantum efficiency measurements is about 1.54 eV. The solar cell fabricated with Glass/Mo/CZTS/CdS/ZnO:Al/Al structure grown using [a = Cu/(Zn + Sn) = 1.1] showed the best conversion efficiency of 4.13% with V{sub oc} = 700 mV, J{sub sc} = 10.01 mA/cm{sup 2} and FF = 0.59.

  19. Natively textured surface hydrogenated gallium-doped zinc oxide transparent conductive thin films with buffer layers for solar cells

    Natively textured surface hydrogenated gallium-doped zinc oxide (HGZO) thin films have been deposited via magnetron sputtering on glass substrates. These natively textured HGZO thin films exhibit rough pyramid-like textured surface, high optical transmittances in the visible and near infrared region and excellent electrical properties. The experiment results indicate that tungsten-doped indium oxide (In2O3:W, IWO) buffer layers can effectively improve the surface roughness and enhance the light scattering ability of HGZO thin films. The root-mean-square roughness of HGZO, IWO (10 nm)/HGZO and IWO (30 nm)/HGZO thin films are 28, 44 and 47 nm, respectively. The haze values at the wavelength of 550 nm increase from 7.0% of HGZO thin film without buffer layer to 18.37% of IWO (10 nm)/HGZO thin film. The optimized IWO (10 nm)/HGZO exhibits a high optical transmittance of 82.18% in the visible and near infrared region (λ ∼ 400–1100 nm) and excellent electrical properties with a relatively low sheet resistance of 3.6 Ω/□ and the resistivity of 6.21 × 10−4 Ωcm. - Highlights: • Textured hydrogenated gallium-doped zinc oxide (HGZO) films were developed. • Tungsten-doped indium oxide (IWO) buffer layers were applied for the HGZO films. • Light-scattering ability of the HGZO films can be improved through buffer layers. • Low sheet resistance and high haze were obtained for the IWO(10 nm)/HGZO film. • The IWO/HGZO films are promising transparent conductive layers for solar cells

  20. Intensity dependence of quantum efficiency and photo-gating effects in thin film silicon solar cells

    Reynolds, Steve; Main, Charles [Carnegie Laboratory of Physics, University of Dundee (United Kingdom); Smirnov, Vladimir [IEF-5 Photovoltaik, Forschungszentrum Juelich (Germany); Meftah, Amjad [Laboratoire des Materiaux Semiconducteurs et Metalliques, Departement de Physique, Universite Mohammed Khider, Biskra (Algeria)

    2010-04-15

    Steady-state photoconductivity measurements have been carried out on thin-film silicon pin structures of i-layer thickness typically 4 {mu}m, where crystalline composition has been varied by adjustment of the silane concentration in the process gas. In amorphous and low-crystallinity cells, strongly-absorbed light incident from the p-side at photon fluxes in excess of 10{sup 14} cm{sup -2} s{sup -1} produces strongly sub-linear intensity dependence, S shaped reverse current-voltage curves and amplification of a second weakly-absorbed beam, termed photogating. These effects are linked to the formation of space charge and attendant low-field region close to the p-i interface, as confirmed by computer simulation. More crystalline devices exhibit little or no such behaviour. At lower intensities of strongly-absorbed light there is a markedly steeper increase in reverse current vs. voltage in low-crystalline when compared to amorphous cells, particularly with light incident from the n-side. This suggests the mobility-lifetime product for holes is much larger in the former case, consistent with the higher hole mobilities reported in time of flight studies. Thus the prospect of composition-dependent changes in mobility as well as defect density should be borne in mind when developing materials for application in microcrystalline silicon solar cells. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Structural, optical, and surface properties of WO3 thin films for solar cells

    Highlights: • WO3 films were deposited by RF reactive sputtering, and annealed in different temperatures. • As deposited films were amorphous while >400 °C annealed films were crystallized as pure monoclinic WO3 phase. • Annealing at 400–500 °C led to an oxygen deficient surface with a sub-stoichiometric WO3−x phase. • Optical bandgap decreased from 3.35 eV to 3.17 eV for the films annealed at 500 °C. • Results are compared with MoO3 films deposited by a similar technique. - Abstract: Transparent back contacts can be used in thin film solar cells facilitating their potential application in tandem cells, bifacial devices and solar windows. In this study, tungsten oxide (WO3) thin films were deposited by Radio Frequency (RF) reactive sputtering in Ar + O2 ambient. The effects of post deposition anneals in air on the structural, optical, and surface properties of the deposited films were investigated using X-ray diffraction, UV/Vis/NIR spectrophotometry, and X-ray photoelectron spectroscopy, respectively. As-deposited films exhibited amorphous structures with no change after annealing at 300 °C. Samples annealed at 400 and 500 °C were crystallized and identified as pure monoclinic WO3 phase with (2 0 0) and (0 0 2) preferred orientation, respectively, determined by XRD fiber texture analysis. Scherrer analysis of excess broadening indicated a coherency length of 50 and 65 nm for the 400 and 500 °C annealed films, respectively. High resolution XPS studies showed the presence of W6+ (WO3) oxidation states at the surface of the as-deposited and the 300 °C annealed films. Annealing at 400–500 °C led to an oxygen deficient surface with a sub-stoichiometric WO3−x phase. UV/Vis/NIR spectrophotometry revealed that post processing decreased the optical bandgap from 3.30 eV for the as-deposited films to 3.17 eV for the 500 °C annealed films. Results are compared with MoO3 films deposited by a similar technique

  2. Structural, optical, and surface properties of WO{sub 3} thin films for solar cells

    Simchi, H., E-mail: simchi@udel.edu [Institute of Energy Conversion, University of Delaware, 451 Wyoming Rd., Newark, DE 19716 (United States); Department of Materials Science and Engineering, University of Delaware, 201 Dupont Hall, Newark, DE 19716 (United States); McCandless, B.E.; Meng, T. [Institute of Energy Conversion, University of Delaware, 451 Wyoming Rd., Newark, DE 19716 (United States); Shafarman, W.N. [Institute of Energy Conversion, University of Delaware, 451 Wyoming Rd., Newark, DE 19716 (United States); Department of Materials Science and Engineering, University of Delaware, 201 Dupont Hall, Newark, DE 19716 (United States)

    2014-12-25

    Highlights: • WO{sub 3} films were deposited by RF reactive sputtering, and annealed in different temperatures. • As deposited films were amorphous while >400 °C annealed films were crystallized as pure monoclinic WO{sub 3} phase. • Annealing at 400–500 °C led to an oxygen deficient surface with a sub-stoichiometric WO{sub 3−x} phase. • Optical bandgap decreased from 3.35 eV to 3.17 eV for the films annealed at 500 °C. • Results are compared with MoO{sub 3} films deposited by a similar technique. - Abstract: Transparent back contacts can be used in thin film solar cells facilitating their potential application in tandem cells, bifacial devices and solar windows. In this study, tungsten oxide (WO{sub 3}) thin films were deposited by Radio Frequency (RF) reactive sputtering in Ar + O{sub 2} ambient. The effects of post deposition anneals in air on the structural, optical, and surface properties of the deposited films were investigated using X-ray diffraction, UV/Vis/NIR spectrophotometry, and X-ray photoelectron spectroscopy, respectively. As-deposited films exhibited amorphous structures with no change after annealing at 300 °C. Samples annealed at 400 and 500 °C were crystallized and identified as pure monoclinic WO{sub 3} phase with (2 0 0) and (0 0 2) preferred orientation, respectively, determined by XRD fiber texture analysis. Scherrer analysis of excess broadening indicated a coherency length of 50 and 65 nm for the 400 and 500 °C annealed films, respectively. High resolution XPS studies showed the presence of W{sup 6+} (WO{sub 3}) oxidation states at the surface of the as-deposited and the 300 °C annealed films. Annealing at 400–500 °C led to an oxygen deficient surface with a sub-stoichiometric WO{sub 3−x} phase. UV/Vis/NIR spectrophotometry revealed that post processing decreased the optical bandgap from 3.30 eV for the as-deposited films to 3.17 eV for the 500 °C annealed films. Results are compared with MoO{sub 3} films deposited by a similar technique.

  3. Controlling the processable ZnO and polythiophene interface for dye-sensitized thin film organic solar cells

    Dye-sensitized thin film hybrid solar cells (DS thin film solar cell) were fabricated by one-pot process using solution processable zinc oxide (ZnO) precursor as electron acceptor, ester-functionalized polythiophene copolymer as donor and a squaraine dye. Incorporation of slight amount of ester functionality (6%) in the regioregular poly-3-hexylthiophene (P3HT) main chain leads to enhancement in the photoconversion efficiency of the ester functionalized polymer (P3HT-E) from 0.8% to about 1% (AM1.5, 100 mw/cm2). Photocurrent associated with both of the P3HT-E (400–650 nm) and the squaraine dye (650–750 nm) were observed in incident photon to current efficiency curve of the DS thin film solar cell. This proves that the ZnO/dye/P3HT-E interface could be fabricated by one-pot coating process from ternary mixture based on a ZnO precursor. - Highlights: • Single step and one pot fabrication of dye-sensitized polymer-ZnO hybrid solar cells. • In situ generation of ZnO using its diethyl zinc precursor. • Enhanced photovoltaic performance by introduction of ester functionalized polymers. • Demonstration of far-red photon harvesting by polymer-dye-ZnO ternary blend

  4. New strategy to promote conversion efficiency using high-index nanostructures in thin-film solar cells

    Wang, DongLin

    2014-01-01

    Nano-scaled metallic or dielectric structures may provide various ways to trap light into thin-film solar cells for improving the conversion efficiency. In most schemes, the textured active layers are involved into light trapping structures that can provide perfect optical benefits but also bring undesirable degradation of electrical performance. Here we propose a novel approach to design high-performance thin-film solar cells. In our strategy, a flat active layer is adopted for avoiding electrical degradation, and an optimization algorithm is applied to seek for an optimized light trapping structure for the best optical benefit. As an example, we show that the efficiency of a flat a-Si:H thin-film solar cell can be promoted close to the certified highest value. It is also pointed out that, by choosing appropriate dielectric materials with high refractive index (>3) and high transmissivity in wavelength region of 350nm-800nm, the conversion efficiency of solar cells can be further enhanced.

  5. Enhanced photocurrent in thin-film amorphous silicon solar cells via shape controlled three-dimensional nanostructures

    In this paper, we have explored manufacturable approaches to sub-wavelength controlled three-dimensional (3D) nano-patterns with the goal of significantly enhancing the photocurrent in amorphous silicon solar cells. Here we demonstrate efficiency enhancement of about 50% over typical flat a-Si thin-film solar cells, and report an enhancement of 20% in optical absorption over Asahi textured glass by fabricating sub-wavelength nano-patterned a-Si on glass substrates. External quantum efficiency showed superior results for the 3D nano-patterned thin-film solar cells due to enhancement of broadband optical absorption. The results further indicate that this enhanced light trapping is achieved with minimal parasitic absorption losses in the deposited transparent conductive oxide for the nano-patterned substrate thin-film amorphous silicon solar cell configuration. Optical simulations are in good agreement with experimental results, and also show a significant enhancement in optical absorption, quantum efficiency and photocurrent. (paper)

  6. Influence of optical properties of ZnO thin-films deposited by spray pyrolysis and RF magnetron sputtering on the output performance of silicon solar cell

    ZnO thin-films were deposited by spray pyrolysis and RF magnetron sputtering techniques. The optical reflection of these thin-films is measured using UV-Vis spectrophotometer. The measured optical reflection data is used in PC-1D simulation software to study the output performance of commercial silicon wafer-based solar cell. As far as optical performance is concerned it could be demonstrated that the sprayed ZnO thin-film under laboratory conditions show equivalent performance compared to sputtered ZnO thin-film. The influence of optical properties of 65 nm thick zinc oxide thin-films deposited by vacuum and non-vacuum techniques on quantum efficiency and IV characteristics of commercial silicon-wafer based solar cell is studied and reported here.

  7. Simulation approach for studying the performances of original superstrate CIGS thin films solar cells

    Bouchama, I., E-mail: bouchama_idris@yahoo.fr [Laboratoire Procedes Materiaux et Energie solaire PROMES-CNRS, Rambla de la Thermodynamique, Technosud, 66100 Perpignan (France); Laboratoire L.I.S., Universite Ferhat Abbas de Setif (Algeria); Djessas, K. [Laboratoire Procedes Materiaux et Energie solaire PROMES-CNRS, Rambla de la Thermodynamique, Technosud, 66100 Perpignan (France); Djahli, F. [Laboratoire L.I.S., Universite Ferhat Abbas de Setif (Algeria); Bouloufa, A. [Laboratoires C.C.N.S. et E. M., Universite Ferhat Abbas de Setif (Algeria)

    2011-08-31

    In this work, we report on the performances of superstrate Cu(In,Ga)Se{sub 2} (CIGS) thin film solar cells with an alternative SLG/SnO{sub 2}:F/CIGS/In{sub 2}Se{sub 3}/Zn structure using AMPS-1D (Analysis of Microelectronic and Photonic structures) device simulator. An inverted surface layer, n-type CIGS layer, is inserted between the In{sub 2}Se{sub 3} buffer and CIGS absorber layers and the SnO{sub 2}:F layer is just a transparent conducting oxide (TCO). The simulation has been carried out by lighting through SnO{sub 2}:F. The obtained results show that the existence of so-called 'ordered defect compound' (ODC) layer in such a structure is the critical factor responsible for the optimization of the performances. Photovoltaic parameters were determined using the current density-voltage (J-V) curve. An optimal absorber and ODC layer thickness has been estimated, that improve significantly the devices efficiency exceeding 15% AM1.5 G. The variation of carrier density in In{sub 2}Se{sub 3} layer has an influence on the superstrate CIGS cells performances. Moreover, the quantum efficiency (Q.E.) characteristics display a maximum value of about 80% in the visible range.

  8. A blazed grating for light trapping in a-Si thin-film solar cells

    A blazed grating has been studied to improve light absorption in thin-film solar cells (TFSCs). The grating is a periodic arrangement of wedges made of aluminum zinc oxide (AZO) that also serves as the back spacer. The absorber layer of the photovoltaic (PV) device can be made of inorganic or organic semiconductor material. Here we study hydrogenated amorphous silicon (a-Si:H) and nano-crystalline Si (nc-Si). Full wave, finite element simulations were performed to optimize the design for the highest short circuit current (Jsc). The Jsc of the optimized 1D grating design was 16.05 mA cm?2 for TE polarization and 15.18 mA cm?2 for TM polarization, with an effective a-Si:H layer thickness of only 277 nm. As compared to a planar cell with the same volume of a-Si:H, the enhancement of Jsc by the 1D grating design was 27.6% for TE polarization and 20.7% for TM polarization. We extended this design to a 2D grating structure that was less sensitive to polarization as compared to the 1D grating design. With an equivalent a-Si:H layer thickness of 322 nm, the optimized design yielded a Jsc of 17.16 mA cm?2. The blazed grating surface can be fabricated using the glancing angle deposition method. (paper)

  9. Simulation approach for studying the performances of original superstrate CIGS thin films solar cells

    In this work, we report on the performances of superstrate Cu(In,Ga)Se2 (CIGS) thin film solar cells with an alternative SLG/SnO2:F/CIGS/In2Se3/Zn structure using AMPS-1D (Analysis of Microelectronic and Photonic structures) device simulator. An inverted surface layer, n-type CIGS layer, is inserted between the In2Se3 buffer and CIGS absorber layers and the SnO2:F layer is just a transparent conducting oxide (TCO). The simulation has been carried out by lighting through SnO2:F. The obtained results show that the existence of so-called 'ordered defect compound' (ODC) layer in such a structure is the critical factor responsible for the optimization of the performances. Photovoltaic parameters were determined using the current density-voltage (J-V) curve. An optimal absorber and ODC layer thickness has been estimated, that improve significantly the devices efficiency exceeding 15% AM1.5 G. The variation of carrier density in In2Se3 layer has an influence on the superstrate CIGS cells performances. Moreover, the quantum efficiency (Q.E.) characteristics display a maximum value of about 80% in the visible range.

  10. Broadband light trapping in thin film solar cells with self-organized plasmonic nano-colloids.

    Mendes, Manuel J; Morawiec, Seweryn; Mateus, Tiago; Lyubchyk, Andriy; Águas, Hugo; Ferreira, Isabel; Fortunato, Elvira; Martins, Rodrigo; Priolo, Francesco; Crupi, Isodiana

    2015-03-27

    The intense light scattered from metal nanoparticles sustaining surface plasmons makes them attractive for light trapping in photovoltaic applications. However, a strong resonant response from nanoparticle ensembles can only be obtained if the particles have monodisperse physical properties. Presently, the chemical synthesis of colloidal nanoparticles is the method that produces the highest monodispersion in geometry and material quality, with the added benefits of being low-temperature, low-cost, easily scalable and of allowing control of the surface coverage of the deposited particles. In this paper, novel plasmonic back-reflector structures were developed using spherical gold colloids with appropriate dimensions for pronounced far-field scattering. The plasmonic back reflectors are incorporated in the rear contact of thin film n-i-p nanocrystalline silicon solar cells to boost their photocurrent generation via optical path length enhancement inside the silicon layer. The quantum efficiency spectra of the devices revealed a remarkable broadband enhancement, resulting from both light scattering from the metal nanoparticles and improved light incoupling caused by the hemispherical corrugations at the cells' front surface formed from the deposition of material over the spherically shaped colloids. PMID:25760231

  11. Absorption enhancement in thin film a-Si solar cells with double-sided SiO2 particle layers

    Chen, Le; Wang, Qing-Kang; Shen, Xiang-Qian; Chen, Wen; Huang, Kun; Liu, Dai-Ming

    2015-10-01

    Light absorption enhancement is very important for improving the power conversion efficiency of a thin film a-Si solar cell. In this paper, a thin-film a-Si solar cell model with double-sided SiO2 particle layers is designed, and then the underlying mechanism of absorption enhancement is investigated by finite difference time domain (FDTD) simulation; finally the feasible experimental scheme for preparing the SiO2 particle layer is discussed. It is found that the top and bottom SiO2 particle layers play an important role in anti-reflection and light trapping, respectively. The light absorption of the cell with double-sided SiO2 layers greatly increases in a wavelength range of 300 nm-800 nm, and the ultimate efficiency increases more than 22% compared with that of the flat device. The cell model with double-sided SiO2 particle layers reported here can be used in varieties of thin film solar cells to further improve their performances. Project supported by the National High-Tech Research and Development Program of China (Grant No. 2011AA050518), the University Research Program of Guangxi Education Department, China (Grant No. LX2014288), and the Natural Science Foundation of Guangxi Zhuang Autonomous Region, China (Grant No. 2013GXNSBA019014).

  12. Ion beam treatment of functional layers in thin-film silicon solar cells

    Zhang, Wendi

    2013-10-01

    In silicon thin-film solar cells, transparent conductive layers have to fulfill the following requirements: high conductivity as effective contact, high transparency to transmit the light into the cell, and a textured surface which provides light scattering. Magnetron sputtered and wet-chemically textured aluminum doped zinc oxide (ZnO:Al) films are widely used as the transparent conductor. The technological goal of this dissertation is to develop an alternative to the wet etching process for light trapping in the thin silicon absorber layers through modification of the glass/ZnO:Al or ZnO:Al/Si interfaces by ion beam treatment. The study focuses on the textured growth of ZnO:Al films on ion beam pretreated glass substrates, and the preparation and application of textured glass for light trapping. The technological aspects such as the etch rates of the glass substrate and ZnO:Al films with different ion beam configurations were studied. The experimental etch rates are compared with simulated and theoretically predicted values. With regard to the ion beam treatment of glass substrate, the influence of the ion pretreated glass on the growth of ZnO:Al films was investigated. The ZnO:Al films grown on ion beam pretreated glass substrates exhibit self-textured morphology with surface roughness of 40 nm while remaining highly conductive. Silicon thin-film solar cells prepared on the as-grown rough ZnO:Al films show that this front contact can provide excellent light trapping effect. The highest initial efficiencies for amorphous single junction solar cells on as-grown rough ZnO:Al films was 9.4%. The as-grown rough morphology was attributed to large conical ZnO:Al grains initiated from the ion pretreated glass surface. It was found that the roughness of the as-grown rough ZnO:Al film is proportional to the number of O dangling bonds created by ion beam treatment on the glass substrate. A growth model was proposed to explain the growth mechanism of ZnO:Al films on Zn- and O-polar ZnO single crystals, as well as on untreated and ion beam treated glass substrates. With regard to the ion beam treatment of ZnO:Al films, the influence of the ion treatment on the surface morphology, HCl etching, silicon growth, and additional ZnO:Al growth was investigated. Ion beam etching has a smoothening effect on the textured ZnO:Al films. Using sputtered and wet chemically etched ZnO:Al as ion beam etching mask, textured glass with features similar to the ZnO:Al films were obtained. Textured glass with a wide range of morphologies was prepared by varying the etching mask and the ion beam treatment conditions. Finally, as-grown textured ZnO:Al films prepared on ion beam treated textured glass, which exhibit 'double textured' features, were produced and applied in solar cells. The ion beam treatment enabled the preparation of light scattering surfaces by textured glass and as-grown rough ZnO:Al films without the need of wet etching between TCO preparation and absorber deposition. Further, new 'double textured' surface structures could be created by the combination of both techniques. Solar cells with efficiency of 11.9% proved the applicability as-grown textured ZnO:Al for light trapping. The growth studies provided deeper insights and a new understanding of ZnO structure formation and will govern optimization of ZnO:Al film properties.

  13. Novel R2R Manufacturable Photonic-Enhanced Thin Film Solar Cells; January 28, 2010 -- January 31, 2011

    Slafer, D.; Dalal, V.

    2012-03-01

    Final subcontract report for PV Incubator project 'Novel R2R Manufacturable Photonic-Enhanced Thin Film Solar Cells.' The goal of this program was to produce tandem Si cells using photonic bandgap enhancement technology developed at ISU and Lightwave Power that would have an NREL-verified efficiency of 7.5% on 0.25 cm{sup 2} area tandem junction cell on plastic substrates. This goal was met and exceeded within the timeframe and budget of the program. On smaller area cells, the efficiency was even higher, {approx}9.5% (not verified by NREL). Appropriate polymers were developed to fabricate photonic and plasmonic devices on stainless steel, Kapton and PEN substrates. A novel photonic-plasmon structure was developed which shows a promise of improving light absorption in thin film cells, a better light absorption than by any other scheme.

  14. Cu-doped CdS and its application in CdTe thin film solar cell

    Yi Deng

    2016-01-01

    Full Text Available Cu is widely used in the back contact formation of CdTe thin film solar cells. However, Cu is easily to diffuse from the back contact into the CdTe absorber layer and even to the cell junction interface CdS/CdTe. This phenomenon is generally believed to be the main factor affecting the CdTe solar cell stability. In this study Cu was intentionally doped in CdS thin film to study its effect on the microstructural, optical and electrical properties of the CdS material. Upon Cu doping, the VCd− and the surface-state-related photoluminescence emissions were dramatically decreased/quenched. The presence of Cu atom hindered the recrystallization/coalescence of the nano-sized grains in the as-deposited CdS film during the air and the CdCl2 annealing. CdTe thin film solar cell fabricated with Cu-doped CdS window layers demonstrated much decreased fill factor, which was induced by the increased space-charge recombination near the p-n junction and the worsened junction crystalline quality. Temperature dependent current-voltage curve measurement indicated that the doped Cu in the CdS window layer was not stable at both room and higher temperatures.

  15. Cu-doped CdS and its application in CdTe thin film solar cell

    Deng, Yi; Yang, Jun; Yang, Ruilong; Shen, Kai; Wang, Dezhao; Wang, Deliang

    2016-01-01

    Cu is widely used in the back contact formation of CdTe thin film solar cells. However, Cu is easily to diffuse from the back contact into the CdTe absorber layer and even to the cell junction interface CdS/CdTe. This phenomenon is generally believed to be the main factor affecting the CdTe solar cell stability. In this study Cu was intentionally doped in CdS thin film to study its effect on the microstructural, optical and electrical properties of the CdS material. Upon Cu doping, the VCd- and the surface-state-related photoluminescence emissions were dramatically decreased/quenched. The presence of Cu atom hindered the recrystallization/coalescence of the nano-sized grains in the as-deposited CdS film during the air and the CdCl2 annealing. CdTe thin film solar cell fabricated with Cu-doped CdS window layers demonstrated much decreased fill factor, which was induced by the increased space-charge recombination near the p-n junction and the worsened junction crystalline quality. Temperature dependent current-voltage curve measurement indicated that the doped Cu in the CdS window layer was not stable at both room and higher temperatures.

  16. Reactive sputtering and composition measurements of precursors for Cu2ZnSnS4 thin film solar cells

    Ericson, Tove

    2013-01-01

    Cu2ZnSnS4 (CZTS) is a thin film solar cell material that only contains abundant elements and for which promising conversion efficiencies of 9.2 % have been shown. In this thesis composition measurements and reactive sputtering of precursors for CZTS films have been studied. These precursors can be annealed to create high quality CZTS films. Accurate control and measurement of composition are important for the synthesis process. The composition of a reference sample was determined using Ruther...

  17. Mechanical synthesis of high purity Cu-In-Se alloy nanopowder as precursor for printed CISe thin film solar cells

    Zaghi, Armin E.; Buffiere, Marie; Brammertz, Guy; Batuk, Maria; Lenaers, Nick; Kniknie, Bas; Hadermann, Joke; MEURIS, Marc; Poortmans, Jef; Vleugels, Jef

    2014-01-01

    Mechanical alloying and ball milling are low cost, up-scalable techniques for the preparation of high purity chalcogenide nanopowders to be used as precursor material for printing thin film solar cells. In this study, high purity copper indium selenium (Cu-In-Se) alloy nanopowders with 20-200 nm particle size were synthesized from macroscopic elemental Cu, In and Se powders via mechanical alloying and planetary ball milling. The particle size distribution, morphology, composition, and purity ...

  18. Highly transparent front electrodes with metal fingers for p-i-n thin-film silicon solar cells

    Moulin Etienne; Mller Thomas Christian Mathias; Warzecha Marek; Hoffmann Andre; Paetzold Ulrich Wilhelm; Aeberhard Urs

    2015-01-01

    The optical and electrical properties of transparent conductive oxides (TCOs), traditionally used in thin-film silicon (TF-Si) solar cells as front-electrode materials, are interlinked, such that an increase in TCO transparency is generally achieved at the cost of reduced lateral conductance. Combining a highly transparent TCO front electrode of moderate conductance with metal fingers to support charge collection is a well-established ...

  19. Depth selective laser scribing of thin films for roll-to-roll production of silicon solar cells

    Loeffler, J.; Wipliez, L.A.; De Keijzer, M.A.; Bosman, J.; Soppe, W.J. [ECN Solar Energy, Petten (Netherlands)

    2009-11-15

    Significant cost reductions for thin-film silicon solar cells are expected from a transition to roll-to-roll production. However, in contrast to state-of-the-art batch-type fabrication of glass based products, for thin-film photovoltaic modules on foil substrates no standard processes for one essential production step - the monolithic series interconnection - are presently available. Laser scribing is the preferred technology here as it allows fast, non-contact, local and precise removal of the thin films. ECN is currently developing the technology and setting up a pilot line for the production of tandem solar cells based on microcrystalline and amorphous silicon on steel foil substrates. To allow monolithic series interconnection on these electrically conducting substrates, an insulating layer is required. In the presented module concept, first all layers of the solar cell are deposited, and after that series interconnection can be realized in one process step by three depth selective laser scribes which are then filled by insulating and electrically conductive inks. In this contribution, we present the latest status of our process development on nanosecond pulsed lasers with three different wavelengths to achieve depth selective scribing of these flexible thin film silicon solar cells. To gain more insight into the selectivity of the process, the ablation thresholds of the different layers have been determined. Then, continuous lines were scribed by systematically varying the pulse energy and spot overlap. The required depth selective scribes could be obtained with all employed lasers (wavelengths of 355 nm, 532 nm, and 1064 nm.

  20. High-Performance and Omnidirectional Thin-Film Amorphous Silicon Solar Cell Modules Achieved by 3D Geometry Design.

    Yu, Dongliang; Yin, Min; Lu, Linfeng; Zhang, Hanzhong; Chen, Xiaoyuan; Zhu, Xufei; Che, Jianfei; Li, Dongdong

    2015-11-01

    High-performance thin-film hydrogenated amorphous silicon solar cells are achieved by combining macroscale 3D tubular substrates and nanoscaled 3D cone-like antireflective films. The tubular geometry delivers a series of advantages for large-scale deployment of photovoltaics, such as omnidirectional performance, easier encapsulation, decreased wind resistance, and easy integration with a second device inside the glass tube. PMID:26418573

  1. The effect of ZnS segregation on Zn-rich CZTS thin film solar cells

    Li, Wei; Chen, Jian; Yan, Chang; Hao, Xiaojing, E-mail: xj.hao@unsw.edu.au

    2015-05-25

    Highlights: • Secondary phase segregation in CZTS based solar cells has been studied by TEM. • A “Zn layer exchange” behaviour was found in sulphurisation of Zn/SnCu stacked layers. • XAS reveals a large spike-like CBO (>0.86 eV) between CZTS and ZnS. • Larger ZnS secondary phase proportion increases solar cell’s V{sub oc} but limits J{sub sc}. - Abstract: Analysis of ZnS segregation behaviour and its influence on the device performance has been made on the Zn-rich Cu{sub 2}ZnSnS{sub 4} thin film solar cells. Cross-sectional transmission electron microscopy images reveal that ZnS is the main secondary phase in the Cu{sub 2}ZnSnS{sub 4} layer obtained from a sulphurised Zn/CuSn metallic stack. The excess Zn diffuses from back contact region to top surface of Cu{sub 2}ZnSnS{sub 4} layer accumulating in the form of ZnS. The solar cell with a higher Zn concentration shows a large quantity of isolated ZnS grains at Cu{sub 2}ZnSnS{sub 4} top surface which is close to CdS/Cu{sub 2}ZnSnS{sub 4} heterojunction interface. Soft X-ray absorption spectroscopy indicates a large spike-like conduction band offset between Cu{sub 2}ZnSnS{sub 4} and ZnS. Consequently, such much ZnS precipitates would increase series resistance and generate lower short-circuit current and external quantum efficiency. However, appropriate amount of ZnS at the space charge region of the solar cell has beneficial effects by reducing the heterojunction interface recombination. Therefore, an improved open-circuit voltage and a higher shunt resistance are achieved. This paper provides a possible method to intentionally segregate ZnS at the space charge region by depositing the Zn layer at the bottom of co-sputtered CuSn layer. Although it is difficult to synthesis a pure phase Cu{sub 2}ZnSnS{sub 4} absorber, we can utilise the ZnS secondary phase to improve the Cu{sub 2}ZnSnS{sub 4} solar performance by controlling the Zn-excess amount.

  2. The effect of ZnS segregation on Zn-rich CZTS thin film solar cells

    Highlights: • Secondary phase segregation in CZTS based solar cells has been studied by TEM. • A “Zn layer exchange” behaviour was found in sulphurisation of Zn/SnCu stacked layers. • XAS reveals a large spike-like CBO (>0.86 eV) between CZTS and ZnS. • Larger ZnS secondary phase proportion increases solar cell’s Voc but limits Jsc. - Abstract: Analysis of ZnS segregation behaviour and its influence on the device performance has been made on the Zn-rich Cu2ZnSnS4 thin film solar cells. Cross-sectional transmission electron microscopy images reveal that ZnS is the main secondary phase in the Cu2ZnSnS4 layer obtained from a sulphurised Zn/CuSn metallic stack. The excess Zn diffuses from back contact region to top surface of Cu2ZnSnS4 layer accumulating in the form of ZnS. The solar cell with a higher Zn concentration shows a large quantity of isolated ZnS grains at Cu2ZnSnS4 top surface which is close to CdS/Cu2ZnSnS4 heterojunction interface. Soft X-ray absorption spectroscopy indicates a large spike-like conduction band offset between Cu2ZnSnS4 and ZnS. Consequently, such much ZnS precipitates would increase series resistance and generate lower short-circuit current and external quantum efficiency. However, appropriate amount of ZnS at the space charge region of the solar cell has beneficial effects by reducing the heterojunction interface recombination. Therefore, an improved open-circuit voltage and a higher shunt resistance are achieved. This paper provides a possible method to intentionally segregate ZnS at the space charge region by depositing the Zn layer at the bottom of co-sputtered CuSn layer. Although it is difficult to synthesis a pure phase Cu2ZnSnS4 absorber, we can utilise the ZnS secondary phase to improve the Cu2ZnSnS4 solar performance by controlling the Zn-excess amount

  3. FTIR spectroscopy of silicon carbide thin films prepared by PECVD technology for solar cell application

    Kleinov, Angela; Huran, Jozef; Sasinkov, Vlasta; Pern, Milan; ly, Vladimr.; Packa, Juraj

    2015-09-01

    The plasma CVD reactor with parallel plate electrodes was used for plasma enhanced chemical vapor deposition (PECVD) of two type's silicon carbide thin films on Si substrates. The concentration of elements in the films was determined by RBS and ERD analytical method simultaneously. The chemical compositions of the samples were analyzed by FTIR method. RBS and ERD results showed that the films contain silicon, carbon, hydrogen and small amount of oxygen. FTIR results confirmed the presence of Si-C, Si-H, C-H, and Si-O bonds. From the FTIR spectra the main following vibration frequencies were determined: the band from 2800 to 3000 cm-1 is attributed to stretching vibration of the CHn group in both the sp2 (2880 cm-1) and sp3 (2920 cm-1) configurations. The band at 2100 cm-1 is due to SiHm stretching vibrations. The band at 780 cm-1 can be assigned to Si-C stretching vibration. Main features of FTIR spectra were Gaussian fitted and detailed analyses of chemical bonding in SiC films were performed. Differences between two types of SiC films were discussed with the aim to using these films in the heterojunction solar cell technology.

  4. The crystal structure of CdS-CdTe thin film heterojunction solar cells

    Rogers, K.D.; Painter, J.D.; Healy, M.J.; Lane, D.W. [Cranfield Univ. (United Kingdom). Dept. of Mater. and Medical Sci.; Ozsan, M.E. [B.P. Solar Ltd., Middlesex (United Kingdom)

    1999-02-08

    A detailed structural analysis of electrodeposited CdS-CdTe thin film heterojunction solar cells was undertaken. X-ray diffraction and Rutherford backscattering spectrometry were used to provide stoichiometric and microcrystalline data at increasing depths through the CdTe and CdS films. A model of the nature and extent of interdiffusion caused by a post deposition anneal is developed. A region in both pre-annealed and post-annealed samples which possesses a significantly different microstructure to that of the bulk CdTe, was identified. Within this region a stoichiometric gradient occurs and the grain size and preferred orientation decrease with increasing depth. Maximum CdTe film stress (post anneal) is estimated to be 140 MPa close to the interface and a shift in optical band gap of 6 x 10{sup -3} eV was also determined from structural measurements. We provide evidence that sulphur diffusion into CdTe is structurally rather than thermodynamically limited within these systems. (orig.) 15 refs.

  5. Dip coated nanocrystalline CdZnS thin films for solar cell application

    Nanocrystalline cadmium sulfide (CdS) and zinc cadmium sulfide (ZnCdS) thin films have been grown via simple and low cost dip coating technique. The prepared films are characterized by X-ray diffraction (XRD), atomic force microscopic (AFM) and UV-VIS spectrophotometer techniques to reveal their structural, morphological and optical properties. XRD shows that both samples grown have zinc blende structure. The grain size is calculated as 6.2 and 8 nm using Scherrer’s formula. The band gap value of CdS and CdZnS film is estimated to be 2.58 and 2.69 eV respectively by UV-vis spectroscopy. Photoelectrochemical (PEC) investigations are carried out using cell configuration as n-CdZnS/(1M NaOH + 1M Na2S + 1M S)/C. The photovoltaic output characteristic is used to calculate fill-factor (FF) and solar conversion efficiency (η)

  6. Double-layer indium doped zinc oxide for silicon thin-film solar cell prepared by ultrasonic spray pyrolysis

    Indium doped zinc oxide (ZnO:In) thin films were prepared by ultrasonic spray pyrolysis on corning eagle 2000 glass substrate. 1 and 2 at.% indium doped single-layer ZnO:In thin films with different amounts of acetic acid added in the initial solution were fabricated. The 1 at.% indium doped single-layers have triangle grains. The 2 at.% indium doped single-layer with 0.18 acetic acid adding has the resistivity of 6.8210?3 ?cm and particle grains. The double-layers structure is designed to fabricate the ZnO:In thin film with low resistivity (2.5810?3 ?cm) and good surface morphology. It is found that the surface morphology of the double-layer ZnO:In film strongly depends on the substrate-layer, and the second-layer plays a large part in the resistivity of the double-layer ZnO:In thin film. Both total and direct transmittances of the double-layer ZnO:In film are above 80% in the visible light region. Single junction a-Si:H solar cell based on the double-layer ZnO:In as front electrode is also investigated. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  7. Influence of thickness on physical properties of vacuum evaporated polycrystalline CdTe thin films for solar cell applications

    Chander, Subhash; Dhaka, M. S.

    2016-02-01

    This paper presents the influence of thickness on physical properties of polycrystalline CdTe thin films. The thin films of thickness 450 nm, 650 nm and 850 nm were deposited employing thermal vacuum evaporation technique on glass and indium tin oxide (ITO) coated glass substrates. The physical properties of these as-grown thin films were investigated employing the X-ray diffraction (XRD), source meter, UV-Vis spectrophotometer, scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The structural analysis reveals that the films have zinc-blende cubic structure and polycrystalline in nature with preferred orientation (111). The structural parameters like lattice constant, interplanar spacing, grain size, strain, dislocation density and number of crystallites per unit area are calculated. The average grain size and optical band gap are found in the range 15.16-21.22 nm and 1.44-1.63 eV respectively and observed to decrease with thickness. The current-voltage characteristics show that the electrical conductivity is observed to decrease with thickness. The surface morphology shows that films are free from crystal defects like pin holes and voids as well as homogeneous and uniform. The EDS patterns show the presence of cadmium and tellurium elements in the as grown films. The experimental results reveal that the film thickness plays significant role on the physical properties of as-grown CdTe thin films and higher thickness may be used as absorber layer to solar cells applications.

  8. Aqueous Solution-Phase Selenized CuIn(S,Se)2 Thin Film Solar Cells Annealed under Inert Atmosphere.

    Oh, Yunjung; Yang, Wooseok; Kim, Jimin; Woo, Kyoohee; Moon, Jooho

    2015-10-14

    A nonvacuum solution-based approach can potentially be used to realize low cost, roll-to-roll fabrication of chalcopyrite CuIn(S,Se)2 (CISSe) thin film solar cells. However, most solution-based fabrication methods involve highly toxic solvents and inevitably require sulfurization and/or postselenization with hazardous H2S/H2Se gases. Herein, we introduce novel aqueous-based Cu-In-S and Se inks that contain an amine additive for producing a high-quality absorber layer. CISSe films were fabricated by simple deposition of Cu-In-S ink and Se ink followed by annealing under an inert atmosphere. Compositional and phase analyses confirmed that our simple aqueous ink-based method facilitated in-site selenization of the CIS layer. In addition, we investigated the molecular structures of our aqueous inks to determine how crystalline chalcopyrite absorber layers developed without sulfurization and/or postselenization. CISSe thin film solar cells annealed at 550 C exhibited an efficiency of 4.55% under AM 1.5 illumination. The low-cost, nonvacuum method to deposit chalcopyrite absorber layers described here allows for safe and simple processing of thin film solar cells. PMID:26394216

  9. Effect of band-aligned double absorber layers on photovoltaic characteristics of chemical bath deposited PbS/CdS thin film solar cells

    Deuk Ho Yeon; Bhaskar Chandra Mohanty; Seung Min Lee; Yong Soo Cho

    2015-01-01

    Here we report the highest energy conversion efficiency and good stability of PbS thin film-based depleted heterojunction solar cells, not involving PbS quantum dots. The PbS thin films were grown by the low cost chemical bath deposition (CBD) process at relatively low temperatures. Compared to the quantum dot solar cells which require critical and multistep complex procedures for surface passivation, the present approach, leveraging the facile modulation of the optoelectronic properties of t...

  10. Polycrystalline silicon thin film solar cells prepared by PECVD-SPC

    Buitrago, R.H.; Risso, G.A.; Cutrera, M.; Battioni, M.; De Bernardez, L.; Schmidt, J.A.; Arce, R.D.; Koropecki, R.R. [Instituto de Desarrollo Tecnologico para la Industria Quimica, CONICET-UNL, Guemes 3450, CP 3000, Santa Fe (Argentina)

    2008-07-15

    Among the most promising technological alternatives for the development of photovoltaic modules and cells of a low cost, good energetic conversion and feasibility for mass production, polycrystalline silicon thin film solar cells deposited directly on a transparent substrate are currently being considered the best. We have developed in our laboratory a PECVD reactor capable of producing the deposition of amorphous hydrogenated silicon at rates of above 2 nm/seg, allowing a significant production per line on the plant. Discharge gas is silane, to which diborane or phosphine is added so as to form the cell. Basically, work is done on a structure of cell type TCO/n+/p-/p+/M, which has 2 {mu}m of total thickness. Schott AF-37 glass is used as a substrate, for their ability to withstand temperatures of up to 800 C. The amorphous cell is subsequently annealed at gradual temperatures of 100 C to achieve dehydrogenation up to 650-700 C for 12 h until their complete crystallization is achieved. Our results show a complete crystallization of silicon with a grain size of less than a micron, with a dehydrogenation process at 500 C, leaving a remainder of less than 1% in hydrogen as monohydrate. The parameters of the cell estimated from the IV curve yield low values, FF<0.55, Icc <200 {mu}A and Voc<420 mV. The high series resistance is due to the grain size and defect density, which will be attempted to be improved by post-hydrogenation and rapid thermal annealing (RTA) methods at high temperatures. (author)

  11. Optimized conditions for the improvement of thin film CdS/CdTe solar cells

    Efficient thin film CdS/CdTe solar cell performance requires optimum parameters of each layer of this cell and of the barrier structure. Moreover, the effect of optical losses, recombination losses at front and back surface of CdTe and recombination losses in the space-charge region (SCR) must be considered in order to really analyze the role of these parameters on the performance of these cells. This work is focused on studying theoretically the effect of the thickness of the front contact (ITO), thickness of the window layer (CdS), thickness of the absorber layer (CdTe), width of the space-charge region and electron lifetime on the efficiency of CdS/CdTe solar cells. The reflection losses from interfaces and absorption losses in ITO and CdS, front and rear surface recombination losses of CdTe as well as recombination losses in SCR have been studied. It has been observed that the short-circuit current strongly depends on the thickness of ITO, thickness of CdS, thickness CdTe and electron lifetime. The concentration of uncompensated impurities (Na − Nd) in CdTe, which determines the width of SCR, plays a key role in the generation of photocurrent. The recombination losses in the SCR decrease rapidly with increasing the carrier lifetime in this region and can be ignored at lifetime of 10−7 s. The reflectivity from the back contact introduces a small influence in increasing the short-current density particularly at thick absorber layer (5–8 μm). Under the conditions of Na − Nd ~ 1016 cm−3, τn = 10−6 s, dCdTe = 8 μm, dITO = 100 nm, and dCdS = 100 nm, the recombination and optical losses record their minimum ratio of 27%. Most of these losses (24%) are due to the optical losses. The efficiency of CdS/CdTe under these parameters is about 18.2% which is exactly matching with the recent experimental studies. Moreover, an ultrathin CdTe (= 1 μm) is sufficient to introduce high efficiency of 16.4%. - Highlights: • This work represents a theoretical study of CdS/CdTe solar cells. • The calculations are carried out based on the optical and recombination losses. • Effects of each layer in this cell and back contact reflectivity are considered. • Efficiency of 18.2% is achieved and it agrees with the recent experimental studies

  12. Co-electroplated Kesterite Bifacial Thin-Film Solar Cells: A Study of Sulfurization Temperature.

    Ge, Jie; Chu, Junhao; Yan, Yanfa; Jiang, Jinchun; Yang, Pingxiong

    2015-05-20

    Earth-abundant material, kesterite Cu2ZnSnS4 (CZTS), demonstrates the tremendous potential to serve as the absorber layer for the bifacial thin-film solar cell. The exploration of appropriate sulfurization conditions including annealing temperature is significant to gain insight into the growth mechanism based on the substrates using transparent conductive oxides (TCO) and improve device performance. The kesterite solar absorbers were fabricated on ITO substrates by sulfurizing co-electroplated Cu-Zn-Sn-S precursors in argon diluted H2S atmosphere at different temperatures (475-550 C) for 30 min. Experimental proof, including cross-section scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, UV-vis-NIR transmission spectrum, and Raman and far-infrared spectroscopy, is presented for the crystallization of CZTS on an ITO substrate and the interfacial reaction between the ITO back contact and CZTS absorber. The complete conversion of precursor into CZTS requires at least 500 C sulfurization temperature. The aggressive interfacial reaction leading to the out-diffusion of In into CZTS to a considerable extent, formation of tin sulfides, and electrically conductive degradation of ITO back contact occurs at the sulfurization temperatures higher than 500 C. The bifacial devices obtained by 520 C sulfurization exhibit the best conversion efficiencies and open circuit voltages. However, the presence of non-ohmic back contact (secondary diode), the short minority lifetime, and the high interfacial recombination rates negatively limit the open circuit voltage, fill factor, and efficiency, evidenced by illumination/temperature-dependent J-V, frequency-dependent capacitance-voltage (C-V-f), time-resolved PL (TRPL), and bias-dependent external quantum efficiency (EQE) measurements. PMID:25871647

  13. Photon confinement in high-efficiency, thin-film III-V solar cells obtained by epitaxial lift-off

    Using the epitaxial lift-off (ELO) technique, a III-V device structure can be separated from its GaAs substrate by selective wet etching of a thin release layer. The thin-film structures obtained by the ELO process can be cemented or van der Waals bonded on arbitrary smooth surface carriers for further processing. It is shown that the ELO method, initially able to separate millimetre-sized GaAs layers with a lateral etch rate of about 1 mm/h, has been developed to a process capable to free the entire 2-in. epitaxial structures from their substrates with etch rates up to 30 mm/h. With these characteristics the method has a large potential for the production of high efficiency thin-film solar cells. By choosing the right deposition and ELO strategy, the thin-film III-V cells can be adequately processed on both sides allowing for an entire range of new cell structures. In the present work, the performance of semi-transparent bifacial solar cells, produced by the deposition of metal grid contacts on both sides, was evaluated. Reflection of light at the rear side of the bifacial GaAs solar cells was found to result in an enhanced collection probability of the photon-induced carriers compared to that of regular III-V cells on a GaAs substrate. To enhance this effect, thin-film GaAs cells with gold mirror back contacts were prepared. Even in their present premature stage of development, these single-junction thin-film cells reached a record efficiency of 24.5% which is already very close to the 24.9% efficiency that was obtained with a regular GaAs cell on a GaAs substrate. From this it could be concluded that, as a result of the photon confinement, ELO cells require a significantly thinner base layer than regular GaAs cells while at the same time they have the potential to reach a higher efficiency

  14. In situ monitoring the growth of thin-film ZnS/Zn (S,O) bilayer on Cu-chalcopyrite for high performance thin film solar cells

    Saez-Araoz, R.; Abou-Ras, D. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Solar Energy Division, Glienicker Strasse 100, 14109 Berlin (Germany); Niesen, T.P. [AVANCIS GmbH and Co KG Otto-Hahn-Ring 6, 81739 Munich (Germany); Neisser, A.; Wilchelmi, K. [SULFURCELL Solartechnik GmbH Barbara-McClintock-Strasse 11, 12489 Berlin (Germany); Lux-Steiner, M.Ch. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Solar Energy Division, Glienicker Strasse 100, 14109 Berlin (Germany); Ennaoui, A. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Solar Energy Division, Glienicker Strasse 100, 14109 Berlin (Germany)], E-mail: ennaoui@helmholtz-berlin.de

    2009-02-02

    This paper highlights the crucial role that the control of the chemical bath deposition (CBD) process plays for buffer production of Cu-chalcopyrite solar-cell devices. ZnS/Zn (S,O) bilayer was deposited on CuInS{sub 2} (CIS) and Cu(In,Ga)(SSe){sub 2} (CIGSSe) and monitored using turbidity measurements of the solution. The results were correlated to the X-ray photoemission spectra of the samples obtained by interruption of the process at sequential stages. Two different feature regimes were distinguished: In the first stage, a heterogeneous reaction takes place on the absorber resulting in the formation of pure ZnS. The second stage of the process is homogeneous, and the in-situ turbidity measurement shows a loss in the transmission of light through the CBD solution. The measured ZnL3M45M45 Auger-peaks, during this second stage of the process, show a shift of the kinetic energy from pure ZnS to a solid-solution ZnS/ZnO ('Zn (S,O)') with decreasing amount of sulfur. These results are supported by the observations from Energy-filtered transmission electron microscopy. This paper also demonstrates that monitoring of the CBD process combined with the basic understanding using surface and interface analysis have contributed to improve the reproducibility and to enhance the photovoltaic performance of Cu-chalcopyrite thin-film solar modules.

  15. Characterization of nanocrystalline SnO2 thin film fabricated by electrodeposition method for dye-sensitized solar cell application

    Nanocrystalline SnO2 thin film was prepared by cathodic electrodeposition-anodic oxidation and its structure was characterized by X-ray diffraction, SEM, UV-visible absorption and nitrogen adsorption-desorption by BET method. The obtained film has a surface area of 137.9 m2/g with grain sized of 24 nm. Thus the prepared SnO2 thin film can be applied as an electrode in dye-sensitized solar cell. The SnO2 electrode was successfully sensitized by Erythrosin dye and photoelectrochemical measurements indicate that the cell present short-circuit photocurrent (Jsc) of 760 μA/cm2, fill factor (FF = 0.4), photovoltage (Voc = 0.21 V) and overall conversion efficiency (η) of 0.06% under direct sun light illumination. The relatively low fill factor and photovoltage are attributed to the reduction of triodiode by conduction band electrons and intrinsic properties of SnO2.

  16. Sputtered Al-doped ZnO transparent conducting thin films suitable for silicon solar cells

    Ben Ayadi, Z., E-mail: Zouhaier.BenAyadi@fsg.rnu.tn [Laboratoire de Physique des Matériaux et des Nanomatériaux appliquée à l' Environnement, Université de Gabès, Faculté des Sciences de Gabès, Cité Erriadh Manara Zrig, 6072 Gabès (Tunisia); Mahdhi, H. [Laboratoire de Physique des Matériaux et des Nanomatériaux appliquée à l' Environnement, Université de Gabès, Faculté des Sciences de Gabès, Cité Erriadh Manara Zrig, 6072 Gabès (Tunisia); Djessas, K. [Laboratoire Procédés, Matériaux et Energie Solaire (PROMES-CNRS), TECNOSUD, Rambla de la Thermodynamique, 66100 Perpignan (France); Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 68860, Perpignan Cedex9 (France); Gauffier, J.L. [Département de Génie Physique, INSA de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse cedex 4 (France); and others

    2014-02-28

    Highly transparent conducting Al-doped zinc oxide (AZO) thin films have been grown onto p-type porous silicon substrates by RF-magnetron sputtering at room temperature using aluminum doped nanocrystalline powder. The obtained AZO films were polycrystalline with a hexagonal wurtzite structure and preferentially oriented in the (002) crystallographic direction. The films are highly transparent in the visible wavelength region with a transmittance higher than 85% and an electrical resistivity of 1.56 × 10{sup −4} Ω·cm was obtained at room temperature. On the other hand, we have studied the position of the p–n junction involved in the In{sub 2}O{sub 3}:SnO{sub 2}/(n)AZO/Si(p) structure, by electron-beam induced current technique. Current density–voltage characterizations in dark and under illumination were also investigated. The cell exhibits an efficiency of 5%. - Highlights: • Al-doped zinc oxide (AZO) thin films were grown by RF-magnetron sputtering. • AZO nanopowder compacted target was prepared by a sol–gel method. • AZO thin films are polycrystalline and have preferred orientation along c-axis. • We report a photovoltaic effect in Si(p)/porous silicon/AZO heterostructure. • The cell exhibits an efficiency of 5%.

  17. Sputtered Al-doped ZnO transparent conducting thin films suitable for silicon solar cells

    Highly transparent conducting Al-doped zinc oxide (AZO) thin films have been grown onto p-type porous silicon substrates by RF-magnetron sputtering at room temperature using aluminum doped nanocrystalline powder. The obtained AZO films were polycrystalline with a hexagonal wurtzite structure and preferentially oriented in the (002) crystallographic direction. The films are highly transparent in the visible wavelength region with a transmittance higher than 85% and an electrical resistivity of 1.56 10?4 ?cm was obtained at room temperature. On the other hand, we have studied the position of the pn junction involved in the In2O3:SnO2/(n)AZO/Si(p) structure, by electron-beam induced current technique. Current densityvoltage characterizations in dark and under illumination were also investigated. The cell exhibits an efficiency of 5%. - Highlights: Al-doped zinc oxide (AZO) thin films were grown by RF-magnetron sputtering. AZO nanopowder compacted target was prepared by a solgel method. AZO thin films are polycrystalline and have preferred orientation along c-axis. We report a photovoltaic effect in Si(p)/porous silicon/AZO heterostructure. The cell exhibits an efficiency of 5%

  18. Experimental study of Cu2ZnSn(Se,S)4 thin films for solar cell applications

    Engman, Jessica

    2011-01-01

    Cu2ZnSn(Se,S)4 (CZT(Se,S)) has recently been shown to be a promising material to use in thin film solar cells. It has a band gap of between 1eV (CZTSe) and 1.5eV (CZTS). CZT(Se,S) solar cells have reached 10% efficiency. The aim of this project was to find an effective way to selenise metallic Cu, Zn, Sn films in order to produce Cu2ZnSnSe4 (CZTSe) films, without destroying the metallic molybdenum (Mo) back contact. Another aim was to make films containing both Se and S and to study the pos...

  19. Carbon-Nanotube Conductive Layers for Thin-Film Solar Cells

    Landis, Geoffrey A.

    2005-01-01

    Thin, transparent layers comprising mats of carbon nanotubes have been proposed for providing lateral (that is, inplane) electrical conductivities for collecting electric currents from the front surfaces of the emitter layers of thin-film solar photovoltaic cells. Traditionally, thin, semitransparent films of other electrically conductive materials (usually, indium tin oxide, zinc oxide, or cadmium sulfide) have been used for this purpose. As in the cases of the traditional semitransparent conductive films, the currents collected by the nanotube layers would, in turn, be further collected by front metal contact stripes. Depending on details of a specific solar-cell design, the layer of carbon nanotubes would be deposited in addition to, or instead of, a semitransparent layer of one of these traditional conductive materials (see figure). The proposal is expected to afford the following advantages: The electrical conductivity of the carbon- nanotube layer would exceed that of the corresponding semitransparent layer of traditional electrically conductive material. The greater electrical conductivity of the carbon-nanotube layer would make it possible to retain adequate lateral electrical conductivity while reducing the thickness of, or eliminating entirely, the traditional semitransparent conductive layer. As a consequence of thinning or elimination of the traditional semitransparent conductive layer, less light would be absorbed, so that more of the incident light would be available for photovoltaic conversion. The greater electrical conductivity of the carbon-nanotube layer would make it possible to increase the distance between front metal contact stripes, in addition to (or instead of) thinning or eliminating the layer of traditional semitransparent conductive material. Consequently, the fraction of solar-cell area shadowed by front metal contact stripes would be reduced again, making more of the incident light available for photovoltaic conversion. The electrical conductivities of individual carbon nanotubes can be so high that the mat of carbon nanotubes could be made sparse enough to be adequately transparent while affording adequate lateral electrical conductivity of the mat as a whole. The thickness of the nanotube layer would be chosen so that the layer would contribute significant lateral electrical conductivity, yet would be as nearly transparent as possible to incident light. A typical thickness for satisfying these competing requirements is expected to lie between 50 and 100 nm. The optimum thickness must be calculated by comparing the lateral electrical conductivity, the distance between front metal stripes, and the amount of light lost by absorption in the nanotube layer.

  20. The properties of surface textured ZnO:Al films for thin film solar cells

    Yoo, Jinsu; Lee, Jeonghul; Kim, Seokki; Yoon, Kyunghoon; Park, I. Jun; Dhungel, S. K.; Karunagaran, B.; Mangalaraj, D.; Yi, Junsin

    2005-02-01

    Aluminum doped Zinc Oxide (ZnO:Al) films were deposited by rf magnetron sputtering from a ZnO target mixed with Al2O3 of 2.5 % on to glass substrates maintained at different temperatures ranging from 300 to 673 K. Argon gas pressure during the deposition was in the range 0.3-10 mTorr. Structural, optical and electrical properties of the prepared films have been characterized. As the argon gas pressure was increased, the deposition rate was found to decrease and the surface roughness was increased. Furthermore, the carrier concentration and the Hall mobility were decreased and thus the electrical resistivity increased. Depending on their structural properties, these films develop different surface structures upon post deposition etching in diluted HCl (0.5%). The light scattering properties of suitable film can be controlled over a wide range simply by varying the etching time, substrate temperature and argon pressure. The X-Ray diffraction (XRD) studies showed that the films are highly oriented with their crystallographic c-axis perpendicular to the substrate and almost independent of argon pressure and also an improvement in crystallinity for the films deposited at higher temperature was observed. Measurements of transmission spectra reveal that ZnO:Al films have an average transmission of over 85 % in the wavelength range of 400-800 nm. Also the films showed an excellent electrical resistivity of 1.9 x 10-4 -cm, a value comparable to that for indium tin oxide film presently used as a transparent electrode. Finally, the texture-etched films were successfully applied on substrates for silicon thin film solar cells.

  1. The properties of surface textured ZnO:Al films for thin film solar cells

    Yoo, Jinsu; Dhungel, S.K.; Karunagaran, B.; Mangalaraj, D.; Yi, Junsin [School of Information and Communication Engineering, Sungkyunkwan University, 300 Chunchun-Dong, Jangan-Gu, Suwon city, Kyunggi-Do, 440 746 (Korea); Lee, Jeonghul; Kim, Seokki; Yoon, Kyunghoon; Jun Park, I. [New and Renewable Energy Dept., Korea Institute of Energy Research, Taejon (Korea)

    2005-02-01

    Aluminum doped Zinc Oxide (ZnO:Al) films were deposited by rf magnetron sputtering from a ZnO target mixed with Al{sub 2}O{sub 3} of 2.5 % on to glass substrates maintained at different temperatures ranging from 300 to 673 K. Argon gas pressure during the deposition was in the range 0.3-10 mTorr. Structural, optical and electrical properties of the prepared films have been characterized. As the argon gas pressure was increased, the deposition rate was found to decrease and the surface roughness was increased. Furthermore, the carrier concentration and the Hall mobility were decreased and thus the electrical resistivity increased. Depending on their structural properties, these films develop different surface structures upon post deposition etching in diluted HCl (0.5%). The light scattering properties of suitable film can be controlled over a wide range simply by varying the etching time, substrate temperature and argon pressure. The X-Ray diffraction (XRD) studies showed that the films are highly oriented with their crystallographic c-axis perpendicular to the substrate and almost independent of argon pressure and also an improvement in crystallinity for the films deposited at higher temperature was observed. Measurements of transmission spectra reveal that ZnO:Al films have an average transmission of over 85 % in the wavelength range of 400-800 nm. Also the films showed an excellent electrical resistivity of 1.9 x 10{sup -4} {omega}-cm, a value comparable to that for indium tin oxide film presently used as a transparent electrode. Finally, the texture-etched films were successfully applied on substrates for silicon thin film solar cells. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Thin film solar cells based on the ternary compound Cu{sub 2}SnS{sub 3}

    Berg, Dominik M.; Dale, Phillip J.; Siebentritt, Susanne [University of Luxembourg, Laboratory for Photovoltaics, 41 rue du Brill, L-4422 Belvaux (Luxembourg)

    2011-07-01

    Thin films of kesterite (Cu{sub 2}ZnSn(S/Se){sub 4}) semiconductors are considered promising absorber layer materials for low cost thin film photovoltaic devices. Experimental and theoretical investigations show, however, that the existence region of a single phase kesterite is relatively small making it difficult to grow single phase absorbers. The semiconducting compound Cu{sub 2}SnS{sub 3} is a common secondary phase that forms in Cu and Sn rich kesterite thin films during growth. Its appearance in a kesterite device would limit the V{sub OC} due to its smaller band gap. However, the band gap of about 1 eV, reported hole concentrations of 10{sup 18}cm{sup -3}, and an absorption coefficient in the visible region of 10{sup 5} cm{sup -1} make the Cu{sub 2}SnS{sub 3} compound itself a promising candidate for low cost photovoltaic applications. In this report we demonstrate the successful fabrication of a thin film solar cell based on Cu{sub 2}SnS{sub 3} via a precursor annealing process. The precursor is prepared by low cost electrodeposition. A maximum external quantum efficiency of about 60% at 800 nm and a band gap of 1.0 eV could be measured. To the best of our knowledge, there have been no other reports on the fabrication of Cu{sub 2}SnS{sub 3} based solar cell devices so far. Loss mechanisms and ways to increase efficiency are discussed.

  3. Combined model of non-conformal layer growth for accurate optical simulation of thin-film silicon solar cells

    Sever, M.; Lipovsek, B.; Krc, J.; Campa, A.; Topic, M. [University of Ljubljana, Faculty of Electrical Engineering Trzaska cesta 25, Ljubljana 1000 (Slovenia); Sanchez Plaza, G. [Technical University of Valencia, Valencia Nanophotonics Technology Center (NTC) Valencia 46022 (Spain); Haug, F.J. [Ecole Polytechnique Federale de Lausanne EPFL, Institute of Microengineering IMT, Photovoltaics and Thin-Film Electronics Laboratory, Neuchatel 2000 (Switzerland); Duchamp, M. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons Institute for Microstructure Research, Research Centre Juelich, Juelich D-52425 (Germany); Soppe, W. [ECN-Solliance, High Tech Campus 5, Eindhoven 5656 AE (Netherlands)

    2013-12-15

    In thin-film silicon solar cells textured interfaces are introduced, leading to improved antireflection and light trapping capabilities of the devices. Thin-layers are deposited on surface-textured substrates or superstrates and the texture is translated to internal interfaces. For accurate optical modelling of the thin-film silicon solar cells it is important to define and include the morphology of textured interfaces as realistic as possible. In this paper we present a model of thin-layer growth on textured surfaces which combines two growth principles: conformal and isotropic one. With the model we can predict the morphology of subsequent internal interfaces in thin-film silicon solar cells based on the known morphology of the substrate or superstrate. Calibration of the model for different materials grown under certain conditions is done on various cross-sectional scanning electron microscopy images of realistic devices. Advantages over existing growth modelling approaches are demonstrated - one of them is the ability of the model to predict and omit the textures with high possibility of defective regions formation inside the Si absorber layers. The developed model of layer growth is used in rigorous 3-D optical simulations employing the COMSOL simulator. A sinusoidal texture of the substrate is optimised for the case of a micromorph silicon solar cell. More than a 50 % increase in short-circuit current density of the bottom cell with respect to the flat case is predicted, considering the defect-free absorber layers. The developed approach enables accurate prediction and powerful design of current-matched top and bottom cell.

  4. Doped and multi-compound ZnO-based transparent conducting oxides for silicon thin film solar cells

    Carreras Seguí, Paz

    2013-01-01

    [eng] The objective of the present work is to provide a better understanding of magnetron sputtered transparent conducting oxides based on ZnO in order to use them as electrodes in thin film silicon solar cells at the Grup d'Energia Solar of the Universitat de Barcelona. This thesis presents the properties of magnetron sputtered aluminium and gallium doped ZnO as well as the properties of multi-compound materials deposited by the co-sputtering of zinc oxide and indium tin oxide. The applicati...

  5. Impacts of proton irradiation on optical and electrical properties of Cu(In,Ga)Se2 thin films and solar cells

    The optical and electrical properties of proton irradiated Cu(In,Ga)Se2 (CIGS) solar cells and the thin films that compose the CIGS solar cell structure were investigated. The transmittance and resistivity of transparent conducting oxide window layers remained constant for a fluence of up to 3 × 1015 cm-2. For CIGS thin films, the number of non-radiative recombination center increases under proton irradiation. In CIGS solar cells, decreasing JSC reflected the degradation of the depletion layer of the CdS/CIGS interface. These results constitute the first step in clarifying the degradation mechanism of CIGS solar cells. (author)

  6. Impact of contamination on hydrogenated amorphous silicon thin films and solar cells

    Woerdenweber, Jan

    2011-09-26

    This thesis deals with atmospheric contamination and cross-contamination of boron (single-chamber process) of the intrinsic absorber layer (i-layer) of p-i-n thin film solar cells based on hydrogenated amorphous silicon. The atmospheric contaminations were introduced by means of intentional leaks. Hereby, the focus is on the influence of contamination species (oxygen and nitrogen), quantity of contamination (leak flow), source of contamination (leaks at chamber wall or in the process gas pipe), and plasma power on the properties of solar cells. Thereby, the minimum requirements for the purity of vacuum and process gas as well as leak conditions of the recipient and gas pipe system have been determined. Additionally, deposition regimes were developed, where the incorporation of impurities is significantly suppressed. For standard processes critical levels of nitrogen and oxygen contamination are determined to be {proportional_to} 4 x 10{sup 18} cm{sup -3} and {proportional_to} 2 x 10{sup 19} cm{sup -3}, respectively, for a leak situated at the chamber wall. Above these concentrations the solar cell efficiency deteriorates. In literature, incorporation of oxygen and nitrogen in doping configuration is assumed to be the reason for the cell deterioration. This assumption is supported by additional material studies of contaminated absorber layers done in this work. The difference in critical concentration is due to the higher doping efficiency of nitrogen compared to that for oxygen. Nevertheless, applying an air leak the critical concentrations of O and N are reached almost simultaneously since the incorporation probability of oxygen is about one order of magnitude higher compared to that for nitrogen. Applying a leak in the process gas pipe the critical oxygen contamination level increases to {proportional_to} 2 x 10{sup 20} cm{sup -3} whereas the critical nitrogen level remains unchanged compared to a chamber wall leak. Applying a deposition regime with a very high flow of process gases for oxygen the higher critical contamination level is found as well for a chamber wall leak. Possible reasons for the dependence of the critical oxygen contamination on the deposition regime and the oxygen source may be the following. Before entering the plasma zone the oxygen can react with hydrogen atoms, silane (very high reaction probability), or silane radicals. Mainly, three reaction products may result, namely SiO{sub 2}-clusters, siloxane (SiH{sub 3}-O-SiH{sub 3}), and OH / H{sub 2}O molecules. The SiO{sub 2} is assumed to drop to the bottom of the reactor or to be pumped out. If oxygen is incorporated from siloxane, it is assumed to be electrically inactive. In contrast, oxygen incorporated from hydrogen-oxygen molecules leads to oxygen incorporation in an electrically active configuration. For a source gas pipe leak, the density of silane in the gas pipe is high compared to that for the chamber wall leak. For the chamber wall leak the hydrogen density is assumed to be much higher compared to that for the process gas pipe leak. Thus, the critical oxygen concentration is suggested to increases due to the resulting higher siloxane to OH / H{sub 2}O ratio for the gas pipe leak compared to that in the vicinity of the chamber wall leak. The different critical levels for different deposition regimes can be explained by their oxygen incorporation velocity. The lifetime of the OH / H{sub 2}O molecules is assumed to be shorter, compared to that for the siloxane. As a consequence this might lead to the fact, that oxygen form these molecules is incorporated in one regime (fast incorporation), and in another regime it is not incorporated (slow incorporation). For nitrogen the same critical contamination levels are observed which is attributed to the lack of reactivity of silane and nitrogen. The observed critical impurity concentrations do not change after light-soaking experiments of the solar cells. A further aspect of this thesis is to improve the single-chamber process for the fabrication of amorphous hydrogenated silicon thin-film solar cells. The main aspect is the suppression of boron cross-contamination. Before the deposition of the i-layer a boron doped p-layer is deposited and thus, after the p-layer deposition some of the boron remains in the recipient. In this work different solar cell configurations and reactor treatments are examined for their suppression of the boron cross-contamination. The various treatments are compared for their effectivity, their working principle, and their time consumption. Amongst the investigated reactor treatments the application of a H{sub 2}O-flush or a process chamber evacuation to 9 x 10{sup -7} mbar turned out to be most favourable in order to suppress the boron cross-contamination. (orig.)

  7. Characterization of CdS/CdTe and CdS/CuInSe2 thin film solar cells

    Cheng, L. J.; Nguyen, T. T.; Shyu, C. M.; Basol, B. M.; Yoo, H. I.

    1984-01-01

    A study on low cost polycrystalline thin film CdS/CdTe and CdS/CuInSe2 solar cells using measurements of spectral response and capacitance-voltage-frequency relationships was performed. Because of high concentrations of localized levels in the energy gap existing in materials and at interfaces, the redistribution of charge among the levels due to illumination plays an important role in the collection of light-generated current in these cells. The results illustrate some related phenomena observed in these cells.

  8. Electronic grain boundary properties in polycrystalline Cu(In,Ga)Se2 semiconductors for thin film solar cells

    Solar cells based on polycrystalline Cu(In,Ga)Se2 (CIGSe) thin film absorbers reach the highest energy conversion efficiency among all thin film solar cells. The record efficiency is at least partly attributed to benign electronic properties of grain boundaries (GBs) in the CIGSe layers. However, despite a high amount of research on this phenomenon the underlying physics is not sufficiently understood. This thesis presents an elaborate study on the electronic properties of GBs in CIGSe thin films. Kelvin probe force microscopy (KPFM) was employed to investigate the electronic properties of GBs in dependence of the Ga-content. Five CIGSe thin lms with various Ga-contents were grown by means of similar three stage co-evaporation processes. Both as grown as well as chemically treated (KCN etched) thin films were analyzed. The chemical treatment was employed to remove surface oxides. No difference in electronic GB properties was found with or without the chemical treatment. Therefore, we conclude that a moderate surface oxidation does not alter the electronic properties of GBs. In general, one can observe significant variations of electronic potential barriers at GBs. Under consideration of the averaging effect of the work function signal of nanoscale potential distributions in KPFM measurements which was quantified in the course of this thesis both positive and negative potential barriers in a range between ∼-350 mV and ∼+450 mV were detected. Additionally, variations in the defect densities at GBs between ∼3.1 x 1011 cm-2 and ∼2.1 x 1012 cm-2 were found. However, no correlation between the electronic properties of GBs and the Ga-content of CIGSe thin films was discovered. Consequently, one cannot explain the drop in device efficiency observed for CIGSe thin film solar cells with a high Ga-content by a change of the electronic properties of GBs. Combined KPFM and electron backscatter diffraction measurements were employed for the first time on CIGSe thin films to gather complementary information about both the structural and electronic properties of individual GBs. With the help of this information it was possible to investigate the interrelationship between the symmetry and the electronic potential barrier of GBs. We could reveal that highly symmetric Σ3 GBs have a lower probability to possess a charged potential barrier than lower symmetric non-Σ3 GBs. The assumption of a general symmetry-dependence of the electronic properties of GBs in CIGSe, i.e. a correlation between the particular symmetry of a GB and its potential barrier that is also valid for GBs with symmetries lower than Σ3, could help to explain the large variations of potential barriers observed at GBs in polycrystalline CIGSe thin films.

  9. Electronic grain boundary properties in polycrystalline Cu(In,Ga)Se{sub 2} semiconductors for thin film solar cells

    Baier, Robert

    2012-06-25

    Solar cells based on polycrystalline Cu(In,Ga)Se{sub 2} (CIGSe) thin film absorbers reach the highest energy conversion efficiency among all thin film solar cells. The record efficiency is at least partly attributed to benign electronic properties of grain boundaries (GBs) in the CIGSe layers. However, despite a high amount of research on this phenomenon the underlying physics is not sufficiently understood. This thesis presents an elaborate study on the electronic properties of GBs in CIGSe thin films. Kelvin probe force microscopy (KPFM) was employed to investigate the electronic properties of GBs in dependence of the Ga-content. Five CIGSe thin lms with various Ga-contents were grown by means of similar three stage co-evaporation processes. Both as grown as well as chemically treated (KCN etched) thin films were analyzed. The chemical treatment was employed to remove surface oxides. No difference in electronic GB properties was found with or without the chemical treatment. Therefore, we conclude that a moderate surface oxidation does not alter the electronic properties of GBs. In general, one can observe significant variations of electronic potential barriers at GBs. Under consideration of the averaging effect of the work function signal of nanoscale potential distributions in KPFM measurements which was quantified in the course of this thesis both positive and negative potential barriers in a range between ∼-350 mV and ∼+450 mV were detected. Additionally, variations in the defect densities at GBs between ∼3.1 x 10{sup 11} cm{sup -2} and ∼2.1 x 10{sup 12} cm{sup -2} were found. However, no correlation between the electronic properties of GBs and the Ga-content of CIGSe thin films was discovered. Consequently, one cannot explain the drop in device efficiency observed for CIGSe thin film solar cells with a high Ga-content by a change of the electronic properties of GBs. Combined KPFM and electron backscatter diffraction measurements were employed for the first time on CIGSe thin films to gather complementary information about both the structural and electronic properties of individual GBs. With the help of this information it was possible to investigate the interrelationship between the symmetry and the electronic potential barrier of GBs. We could reveal that highly symmetric Σ3 GBs have a lower probability to possess a charged potential barrier than lower symmetric non-Σ3 GBs. The assumption of a general symmetry-dependence of the electronic properties of GBs in CIGSe, i.e. a correlation between the particular symmetry of a GB and its potential barrier that is also valid for GBs with symmetries lower than Σ3, could help to explain the large variations of potential barriers observed at GBs in polycrystalline CIGSe thin films.

  10. Boron Doped Nanocrystalline Film with Improved Work Function as a Buffer Layer in Thin Film Silicon Solar Cells.

    Park, Jinjoo; Shin, Chonghoon; Park, Hyeongsik; Jung, Junhee; Lee, Youn-Jung; Bong, Sungjae; Dao, Vinh Ai; Balaji, Nagarajan; Yi, Junsin

    2015-03-01

    We investigated thin film silicon solar cells with boron doped hydrogenated nanocrystalline silicon/ hydrogenated amorphous silicon oxide [p-type nc-Si:H/a-SiOx:H] layer. First, we researched the bandgap engineering of diborane (B2H6) doped wide bandgap hydrogenated nanocryslline silicon (p-type nc-Si:H) films, which have excellent electrical properties of high dark conductivity, and low activation energy. The films prepared with lower doping ratio and higher hydrogen dilution ratio had higher optical gap (Eg), with higher dark conductivity (σ(d)), and lower activation energy (Ea). We controlled Eg from 2.10 eV to 1.75 eV, with σ(d) from 1.1 S/cm to 7.59 x 10(-3) S/cm, and Ea from 0.040 eV to 0.128 eV. Next, we focused on the fabrication of thin film silicon solar cells. By inserting p-type nc-Si:H film into the thin film silicon solar cells, we achieved a remarkable increase in the built-in potential from 0.803 eV to 0.901 eV. By forming p-type nc-Si:H film between SnO2:F/ZnO:Al (30 nm) and p-type a-SiOx:H layer, the solar cell properties of open circuit voltage (Voc), short circuit current density (Jsc), and efficiency (η) were improved by 3.7%, 9.2%, and 9.8%, respectively. PMID:26413646

  11. Fabrication of solution processed 3D nanostructured CuInGaS2 thin film solar cells

    In this study we demonstrate the fabrication of CuInGaS2 (CIGS) thin film solar cells with a three-dimensional (3D) nanostructure based on indium tin oxide (ITO) nanorod films and precursor solutions (Cu, In and Ga nitrates in alcohol). To obtain solution processed 3D nanostructured CIGS thin film solar cells, two different precursor solutions were applied to complete gap filling in ITO nanorods and achieve the desirable absorber film thickness. Specifically, a coating of precursor solution without polymer binder material was first applied to fill the gap between ITO nanorods followed by deposition of the second precursor solution in the presence of a binder to generate an absorber film thickness of ∼1.3 μm. A solar cell device with a (Al, Ni)/AZO/i-ZnO/CdS/CIGS/ITO nanorod/glass structure was constructed using the CIGS film, and the highest power conversion efficiency was measured to be ∼6.3% at standard irradiation conditions, which was 22.5% higher than the planar type of CIGS solar cell on ITO substrate fabricated using the same precursor solutions. (paper)

  12. Scattering matrix analysis for evaluating the photocurrent in hydrogenated-amorphous-silicon-based thin film solar cells.

    Shin, Myunghun; Lee, Seong Hyun; Lim, Jung Wook; Yun, Sun Jin

    2014-11-01

    A scattering matrix (S-matrix) analysis method was developed for evaluating hydrogenated amorphous silicon (a-Si:H)-based thin film solar cells. In this approach, light wave vectors A and B represent the incoming and outgoing behaviors of the incident solar light, respectively, in terms of coherent wave and incoherent intensity components. The S-matrix determines the relation between A and B according to optical effects such as reflection and transmission, as described by the Fresnel equations, scattering at the boundary surfaces, or scattering within the propagation medium, as described by the Beer-Lambert law and the change in the phase of the propagating light wave. This matrix can be used to evaluate the behavior of angle-incident coherent and incoherent light simultaneously, and takes into account not only the light scattering process at material boundaries (haze effects) but also nonlinear optical processes within the material. The optical parameters in the S-matrix were determined by modeling both a 2%-gallium-doped zinc oxide transparent conducting oxide and germanium-compounded a-Si:H (a-SiGe:H). Using the S-matrix equations, the photocurrent for an a-Si:H/a-SiGe:H tandem cell and the optical loss in semitransparent a-Si:H solar cells for use in building-integrated photovoltaic applications were analyzed. The developed S-matrix method can also be used as a general analysis tool for various thin film solar cells. PMID:25958519

  13. Sulfur-doped nickel oxide thin film as an alternative to Pt for dye-sensitized solar cell counter electrodes

    Guai, Guan Hong [Center for Advanced Bionanosystems and School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457 (Singapore); GlobalFoundries Singapore Pte. Ltd., 60 Woodlands Industrial Park D, Street 2, Singapore 738406 (Singapore); Leiw, Ming Yian [GlobalFoundries Singapore Pte. Ltd., 60 Woodlands Industrial Park D, Street 2, Singapore 738406 (Singapore); School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Ng, Chee Mang [GlobalFoundries Singapore Pte. Ltd., 60 Woodlands Industrial Park D, Street 2, Singapore 738406 (Singapore); Li, Chang Ming [Center for Advanced Bionanosystems and School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457 (Singapore); Institute for Clean Energy and Advanced Materials, Southwest University, Chongqing 400715 (China)

    2012-03-15

    A low-cost, sulfur-doped NiO (S-NiO) thin film is electrodeposited on fluorine-doped SnO{sub 2} substrate and studied in an iodide-based redox system. High electrochemical activity is present because of a large catalytic surface area and a low charge transfer resistance. A dye- sensitized solar cell with a low-loaded S-NiO counter electrode achieves a power conversion efficiency of 5.04%, close to that of a cell with a conventional platinized electrode. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Integration of a 2D Periodic Nanopattern Into Thin Film Polycrystalline Silicon Solar Cells by Nanoimprint Lithography

    Abdo, Islam; Trompoukis, Christos; Deckers, Jan; Depauw, Valérie; Tous, Loic; Van Gestel, Dries; Guindi, Rafik; Gordon, Ivan; Daif, Ounsi El

    2015-01-01

    The integration of two-dimensional (2D) periodic nanopattern defined by nanoimprint lithography and dry etching into aluminum induced crystallization (AIC) based polycrystalline silicon (Poly-Si) thin film solar cells is investigated experimentally. Compared to the unpatterned cell an increase of 6% in the light absorption has been achieved thanks to the nanopattern which, in turn, increased the short circuit current from 20.6 mA/cm2 to 23.8 mA/cm2. The efficiency, on the other hand, has limi...

  15. Nanostructured p-type CZTS thin films prepared by a facile solution process for 3D p-n junction solar cells

    Park, Si-Nae; Sung, Shi-Joon; Sim, Jun-Hyoung; Yang, Kee-Jeong; Hwang, Dae-Kue; Kim, Junho; Kim, Gee Yeong; Jo, William; Kim, Dae-Hwan; Kang, Jin-Kyu

    2015-06-01

    Nanoporous p-type semiconductor thin films prepared by a simple solution-based process with appropriate thermal treatment and three-dimensional (3D) p-n junction solar cells fabricated by depositing n-type semiconductor layers onto the nanoporous p-type thin films show considerable photovoltaic performance compared with conventional thin film p-n junction solar cells. Spin-coated p-type Cu2ZnSnS4 (CZTS) thin films prepared using metal chlorides and thiourea show unique nanoporous thin film morphology, which is composed of a cluster of CZTS nanograins of 50-500 nm, and the obvious 3D p-n junction structure is fabricated by the deposition of n-type CdS on the nanoporous CZTS thin films by chemical bath deposition. The photovoltaic properties of 3D p-n junction CZTS solar cells are predominantly affected by the scale of CZTS nanograins, which is easily controlled by the sulfurization temperature of CZTS precursor films. The scale of CZTS nanograins determines the minority carrier transportation within the 3D p-n junction between CZTS and CdS, which are closely related with the photocurrent of series resistance of 3D p-n junction solar cells. 3D p-n junction CZTS solar cells with nanograins below 100 nm show power conversion efficiency of 5.02%, which is comparable with conventional CZTS thin film solar cells.Nanoporous p-type semiconductor thin films prepared by a simple solution-based process with appropriate thermal treatment and three-dimensional (3D) p-n junction solar cells fabricated by depositing n-type semiconductor layers onto the nanoporous p-type thin films show considerable photovoltaic performance compared with conventional thin film p-n junction solar cells. Spin-coated p-type Cu2ZnSnS4 (CZTS) thin films prepared using metal chlorides and thiourea show unique nanoporous thin film morphology, which is composed of a cluster of CZTS nanograins of 50-500 nm, and the obvious 3D p-n junction structure is fabricated by the deposition of n-type CdS on the nanoporous CZTS thin films by chemical bath deposition. The photovoltaic properties of 3D p-n junction CZTS solar cells are predominantly affected by the scale of CZTS nanograins, which is easily controlled by the sulfurization temperature of CZTS precursor films. The scale of CZTS nanograins determines the minority carrier transportation within the 3D p-n junction between CZTS and CdS, which are closely related with the photocurrent of series resistance of 3D p-n junction solar cells. 3D p-n junction CZTS solar cells with nanograins below 100 nm show power conversion efficiency of 5.02%, which is comparable with conventional CZTS thin film solar cells. Electronic supplementary information (ESI) available: DETAILS. See DOI: 10.1039/c5nr02081f

  16. A study of the applicability of ZnO thin-films as anti-reflection coating on Cu{sub 2}ZnSnS{sub 4} thin-films solar cell

    Ray, Abhijit; Patel, Malkeshkumar; Tripathi, Brijesh; Kumar, Manoj [School of Solar Energy, Panditdeendayal Petroleum University, Raisan, Gandhinagar, Gujarat (India)

    2012-06-25

    Transparent ZnO thin-films are prepared using the RF magnetron sputtering and spray pyrolysis techniques on the glass substrates. Reflectance spectra and thin films heights are measured using spectrophotometer and stylus surface profiler, respectively. Measured optical data is used for investigating the effect of the ZnO prepared by above two processes on the performance of Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films solar cell (TFSC). One dimensional simulation approach is considered using the simulation program, SCAPS. External quantum efficiency and J-V characteristics of CZTS TFSC is simulated on the basis of optical reflectance data of ZnO films with and without ZnO thin-films as antireflection coating (ARC). Study shows that ARC coated CZTS TFSC provides a better fill factor (FF) as compared to other ARC material such as MgF{sub 2}. Sprayed ZnO thin-films as ARC show comparable performance with the sputtered samples.

  17. A light-trapping strategy for nanocrystalline silicon thin-film solar cells using three-dimensionally assembled nanoparticle structures

    Ha, Kyungyeon; Jang, Eunseok; Jang, Segeun; Lee, Jong-Kwon; Jang, Min Seok; Choi, Hoseop; Cho, Jun-Sik; Choi, Mansoo

    2016-02-01

    We report three-dimensionally assembled nanoparticle structures inducing multiple plasmon resonances for broadband light harvesting in nanocrystalline silicon (nc-Si:H) thin-film solar cells. A three-dimensional multiscale (3DM) assembly of nanoparticles generated using a multi-pin spark discharge method has been accomplished over a large area under atmospheric conditions via ion-assisted aerosol lithography. The multiscale features of the sophisticated 3DM structures exhibit surface plasmon resonances at multiple frequencies, which increase light scattering and absorption efficiency over a wide spectral range from 350-1100 nm. The multiple plasmon resonances, together with the antireflection functionality arising from the conformally deposited top surface of the 3D solar cell, lead to a 22% and an 11% improvement in power conversion efficiency of the nc-Si:H thin-film solar cells compared to flat cells and cells employing nanoparticle clusters, respectively. Finite-difference time-domain simulations were also carried out to confirm that the improved device performance mainly originates from the multiple plasmon resonances generated from three-dimensionally assembled nanoparticle structures.

  18. A light-trapping strategy for nanocrystalline silicon thin-film solar cells using three-dimensionally assembled nanoparticle structures.

    Ha, Kyungyeon; Jang, Eunseok; Jang, Segeun; Lee, Jong-Kwon; Jang, Min Seok; Choi, Hoseop; Cho, Jun-Sik; Choi, Mansoo

    2016-02-01

    We report three-dimensionally assembled nanoparticle structures inducing multiple plasmon resonances for broadband light harvesting in nanocrystalline silicon (nc-Si:H) thin-film solar cells. A three-dimensional multiscale (3DM) assembly of nanoparticles generated using a multi-pin spark discharge method has been accomplished over a large area under atmospheric conditions via ion-assisted aerosol lithography. The multiscale features of the sophisticated 3DM structures exhibit surface plasmon resonances at multiple frequencies, which increase light scattering and absorption efficiency over a wide spectral range from 350-1100 nm. The multiple plasmon resonances, together with the antireflection functionality arising from the conformally deposited top surface of the 3D solar cell, lead to a 22% and an 11% improvement in power conversion efficiency of the nc-Si:H thin-film solar cells compared to flat cells and cells employing nanoparticle clusters, respectively. Finite-difference time-domain simulations were also carried out to confirm that the improved device performance mainly originates from the multiple plasmon resonances generated from three-dimensionally assembled nanoparticle structures. PMID:26751935

  19. Deposition and characterization of amorphous silicon with embedded nanocrystals and microcrystalline silicon for thin film solar cells

    Ambrosio, R., E-mail: rambrosi@uacj.mx [Instituto Nacional de Astrofísica, Óptica y Electrónica, INAOE, Puebla (Mexico); Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, UACJ, C.J., Chihuahua (Mexico); Moreno, M.; Torres, A. [Instituto Nacional de Astrofísica, Óptica y Electrónica, INAOE, Puebla (Mexico); Carrillo, A. [Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, UACJ, C.J., Chihuahua (Mexico); Vivaldo, I.; Cosme, I. [Instituto Nacional de Astrofísica, Óptica y Electrónica, INAOE, Puebla (Mexico); Heredia, A. [Universidad Popular Autónoma del Estado de Puebla, Puebla (Mexico)

    2015-09-15

    Highlights: • Nanostructured silicon thin films were deposited by PECVD. • Polymorphous and microcrystalline were obtained varying the pressure and power. • Structural and optoelectronics properties were studied. • The σ{sub dark} changed by 5 order of magnitude under illumination, V{sub d} was at 2.5 A/s. • The evidence of embedded nanocrystals into the amorphous matrix was investigated. - Abstract: Amorphous silicon thin films with embedded nanocrystals and microcrystalline silicon were deposited by the standard Radio Frequency (RF) Plasma Enhanced Chemical Vapor Deposition (PECVD) technique, from SiH{sub 4}, H{sub 2}, Ar gas mixture at substrate temperature of 200 °C. Two series of films were produced varying deposition parameters as chamber pressure and RF power density. The chemical bonding in the films was characterized by Fourier transform infrared spectroscopy, where it was observed a correlation between the hydrogen content and the morphological and electrical properties in the films. Electrical and optical parameters were extracted in both series of films, as room temperature conductivity (σ{sub RT}), activation energy (E{sub a}), and optical band gap (E{sub g}). As well, structural analysis in the films was performed by Raman spectroscopy and Atomic Force Microscopy (AFM), which gives an indication of the films crystallinity. The photoconductivity changed in a range of 2 and 6 orders of magnitude from dark to AM 1.5 illumination conditions, which is of interest for thin film solar cells applications.

  20. SnS Thin Film Prepared by Pyrolytic Synthesis as an Efficient Counter Electrode in Quantum Dot Sensitized Solar Cells.

    Dai, Xiaoyan; Shi, Chengwu; Zhang, Yanru; Liu, Feng; Fang, Xiaqin; Zhu, Jun

    2015-09-01

    The SnS thin films were successfully prepared by pyrolysis procedure for the counter electrodes in quantum dot sensitized solar cells (QDSCs) using the methanol solution containing stannous chloride dihydrate (0.40 mol x L(-1)) and thiourea (0.40 mol x L(-1)) as precursor solution at 300 degrees C in the air atmosphere. The electrochemical catalytic activity of the SnS thin films prepared by pyrolytic synthesis for the redox couple of S(2-)/S(2-) was investigated by electrochemical impedance spectroscopy. The result revealed that the charge transfer resistance of the as-prepared SnS thin film with the dipping-heating cycles of 5 was 106.4 Ω and the corresponded QDSCs gave a short circuit photocurrent density of 8.69 mA x cm(-2), open circuit voltage of 0.42 V, and fill factor of 0.43, yielding the photoelectric conversion efficiency of 1.57%, under the illumination of simulated AM 1.5 sunlight (100 mWx cm(-2)). PMID:26716249

  1. Deposition and characterization of amorphous silicon with embedded nanocrystals and microcrystalline silicon for thin film solar cells

    Highlights: • Nanostructured silicon thin films were deposited by PECVD. • Polymorphous and microcrystalline were obtained varying the pressure and power. • Structural and optoelectronics properties were studied. • The σdark changed by 5 order of magnitude under illumination, Vd was at 2.5 A/s. • The evidence of embedded nanocrystals into the amorphous matrix was investigated. - Abstract: Amorphous silicon thin films with embedded nanocrystals and microcrystalline silicon were deposited by the standard Radio Frequency (RF) Plasma Enhanced Chemical Vapor Deposition (PECVD) technique, from SiH4, H2, Ar gas mixture at substrate temperature of 200 °C. Two series of films were produced varying deposition parameters as chamber pressure and RF power density. The chemical bonding in the films was characterized by Fourier transform infrared spectroscopy, where it was observed a correlation between the hydrogen content and the morphological and electrical properties in the films. Electrical and optical parameters were extracted in both series of films, as room temperature conductivity (σRT), activation energy (Ea), and optical band gap (Eg). As well, structural analysis in the films was performed by Raman spectroscopy and Atomic Force Microscopy (AFM), which gives an indication of the films crystallinity. The photoconductivity changed in a range of 2 and 6 orders of magnitude from dark to AM 1.5 illumination conditions, which is of interest for thin film solar cells applications

  2. Optimized conditions for the improvement of thin film CdS/CdTe solar cells

    Mohamed, H.A., E-mail: hussein_abdelhafez2000@yahoo.com

    2015-08-31

    Efficient thin film CdS/CdTe solar cell performance requires optimum parameters of each layer of this cell and of the barrier structure. Moreover, the effect of optical losses, recombination losses at front and back surface of CdTe and recombination losses in the space-charge region (SCR) must be considered in order to really analyze the role of these parameters on the performance of these cells. This work is focused on studying theoretically the effect of the thickness of the front contact (ITO), thickness of the window layer (CdS), thickness of the absorber layer (CdTe), width of the space-charge region and electron lifetime on the efficiency of CdS/CdTe solar cells. The reflection losses from interfaces and absorption losses in ITO and CdS, front and rear surface recombination losses of CdTe as well as recombination losses in SCR have been studied. It has been observed that the short-circuit current strongly depends on the thickness of ITO, thickness of CdS, thickness CdTe and electron lifetime. The concentration of uncompensated impurities (N{sub a} − N{sub d}) in CdTe, which determines the width of SCR, plays a key role in the generation of photocurrent. The recombination losses in the SCR decrease rapidly with increasing the carrier lifetime in this region and can be ignored at lifetime of 10{sup −7} s. The reflectivity from the back contact introduces a small influence in increasing the short-current density particularly at thick absorber layer (5–8 μm). Under the conditions of N{sub a} − N{sub d} ~ 10{sup 16} cm{sup −3}, τ{sub n} = 10{sup −6} s, d{sub CdTe} = 8 μm, d{sub ITO} = 100 nm, and d{sub CdS} = 100 nm, the recombination and optical losses record their minimum ratio of 27%. Most of these losses (24%) are due to the optical losses. The efficiency of CdS/CdTe under these parameters is about 18.2% which is exactly matching with the recent experimental studies. Moreover, an ultrathin CdTe (= 1 μm) is sufficient to introduce high efficiency of 16.4%. - Highlights: • This work represents a theoretical study of CdS/CdTe solar cells. • The calculations are carried out based on the optical and recombination losses. • Effects of each layer in this cell and back contact reflectivity are considered. • Efficiency of 18.2% is achieved and it agrees with the recent experimental studies.

  3. A comparative study on the performance of Kesterite based thin film solar cells using SCAPS simulation program

    Simya, O. K.; Mahaboobbatcha, A.; Balachander, K.

    2015-06-01

    A comparative study of thin film solar cells based on CZTS, CZTSe, and CZTSSe (Copper Zinc Tin Sulphur Selenium) absorbers layers were simulated with Cadmium Sulphide (CdS) as buffer layer and Zinc Oxide (ZnO) as window layer using a solar cell capacitance simulator (SCAPS). The influences of series resistance, band to band recombination, defects and interfaces, thickness of (CZTS|CZTSe|CZTSSe) absorber layer, (CdS) buffer layer and transparent conductive oxide layer (ZnO) on the photovoltaic cell parameters were studied in detail. Improvements in efficiency were achieved by changing the back contact metal work function (BMWF) and choosing the flat band option in SCAPS software. Based on the best possible optimisation, an efficiency (?) of 12.03%, 13.16% and 15.77% were obtained for CZTS, CZTSe, and CZTSSe respectively. The performance of thin film photovoltaic devices (TFPV), for Mo back contact before optimisation and the SCAPS simulated values (flat band) after optimisation were described in detail to have in-depth understanding for better design of experiments (DOE) to obtain high efficiency solar cells.

  4. ZnO thin films fabricated by chemical bath deposition, used as buffer layer in organic solar cells

    Lare, Y. [Laboratoire sue l' Energie Solaire, Universite de Lome, Lome (Togo); Godoy, A. [Facultad Ciencias de la Salud, Universidad Diego Portales, Ejercito 141, Santiago de Chile (Chile); Cattin, L. [Universite de Nantes, Nantes Atlantique Universites, IMN, Faculte des Sciences et des Techniques, 2 rue de la Houssiniere, BP 92208, Nantes, F-44000 France (France); Jondo, K. [Laboratoire sue l' Energie Solaire, Universite de Lome, Lome (Togo); Abachi, T. [Ecole Normale Superieure, Kouba, Alger (Algeria); Diaz, F.R. [Laboratorio de Polimeros, Facultad de Quimica, Pontificia Universidad Catolica de Chile, Casilla 306, Correo 22, Santiago (Chile); Morsli, M. [Universite de Nantes, Nantes Atlantique Universites, LAMP, EA 3825, Faculte des Sciences et des Techniques, 2 rue de la Houssiniere, BP 92208, Nantes, F-44000 France (France); Napo, K. [Laboratoire sue l' Energie Solaire, Universite de Lome, Lome (Togo); del Valle, M.A. [Laboratorio de Polimeros, Facultad de Quimica, Pontificia Universidad Catolica de Chile, Casilla 306, Correo 22, Santiago (Chile); Bernede, J.C., E-mail: jean-christian.bernede@univ-nantes.fr [Universite de Nantes, Nantes Atlantique Universites, LAMP, EA 3825, Faculte des Sciences et des Techniques, 2 rue de la Houssiniere, BP 92208, Nantes, F-44000 France (France)

    2009-04-15

    ZnO thin films synthetized by chemical bath deposition are used as buffer layer between the anode and the organic electron donor in organic solar cells. Films deposited from zinc nitrate solutions are annealed in room air at 300 deg. C for half an hour. The X-ray diffraction and microanalysis studies show that ZnO polycrystalline thin films are obtained. The solar cells used are based on the couple copper phthalocyanine as electron donor and (N,N-diheptyl-3,4,9,10-perylenetetracarboxylicdiimide-PTCDI-C7) as electron acceptor. It is shown that the presence of the ZnO buffer layer improves the energy conversion efficiency of the cells. Such improvement could be attributed to a better energy level alignment at the anode/electron donor interface. The anode roughness induced by the ZnO buffer layer can also transform the planar interface organic electron donor/electron acceptor into roughen topography. This increases the interface area, where carrier separation takes place, which improves solar cells performances.

  5. High-efficiency, thin-film solar cells. Annual subcontractor report, 1 July 1991--30 June 1992

    Gale, R.P. [Kopin Corp., Taunton, MA (United States)

    1994-01-01

    This report describes work on a 3-year research program to investigate thin-film GaAs/GaInP cells using the cleavage of lateral epitaxial film for transfer (CLEFT) technique, and to determine the process to enable overgrowth of GaAs films using organometallic chemistry. Application of the CLEFT thin-film technique to GaInP/GaAs solar cells and organometallic overgrowth was investigated. A problem of alloy contamination was identified and controlled, leading to higher quality layers. Solar cell structures were grown and fabricated using previously determined growth parameters for GaAs and GaInP. With the improved materials developed significant improvements were made in solar cell performance. Conditions for in-situ overgrowth by organometallic chemical vapor deposition (OMCVD) were determined and continuous GaAs layers were grown over a separation mask layer. The layers were successfully separated from their substrate using the CLEFT process, demonstrating the application of overgrowth using OM chemistry with HCl.

  6. ZnO thin films fabricated by chemical bath deposition, used as buffer layer in organic solar cells

    ZnO thin films synthetized by chemical bath deposition are used as buffer layer between the anode and the organic electron donor in organic solar cells. Films deposited from zinc nitrate solutions are annealed in room air at 300 deg. C for half an hour. The X-ray diffraction and microanalysis studies show that ZnO polycrystalline thin films are obtained. The solar cells used are based on the couple copper phthalocyanine as electron donor and (N,N-diheptyl-3,4,9,10-perylenetetracarboxylicdiimide-PTCDI-C7) as electron acceptor. It is shown that the presence of the ZnO buffer layer improves the energy conversion efficiency of the cells. Such improvement could be attributed to a better energy level alignment at the anode/electron donor interface. The anode roughness induced by the ZnO buffer layer can also transform the planar interface organic electron donor/electron acceptor into roughen topography. This increases the interface area, where carrier separation takes place, which improves solar cells performances.

  7. Opto-electronic properties of rough LP-CVD ZnO:B for use as TCO in thin-film silicon solar cells

    Polycrystalline Boron-doped ZnO films deposited by low pressure chemical vapor deposition technique are developed for their use as transparent contacts for thin-film silicon solar cells. The size of the columnar grains that constitute the ZnO films is related to their light scattering capability, which has a direct influence on the current generation in thin-film silicon solar cells. Furthermore, if the doping level of the ZnO films is kept below 1 x 1020 cm-3, the electron mobility can be drastically enhanced by growing large grains, and the free carrier absorption is reduced. All these considerations have been taken in account to develop ZnO films finely optimized for the fabrication of microcrystalline thin-film silicon solar cells. These TCO allow the achievement of solar cell conversion efficiencies close to 10%

  8. Electrochemical deposition of molybdenum sulfide thin films on conductive plastic substrates as platinum-free flexible counter electrodes for dye-sensitized solar cells

    In this study, pulsed electrochemical deposition (pulsed ECD) was used to deposit molybdenum sulfide (MoSx) thin films on indium tin oxide/polyethylene naphthalate (ITO/PEN) substrates as flexible counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The surface morphologies and elemental distributions of the prepared MoSx thin films were examined using field-emission scanning electron microscope (FE-SEM) equipped with energy-dispersive X-ray spectroscopy. The chemical states and crystallinities of the prepared MoSx thin films were examined by X-ray photoelectron spectroscopy and X-ray diffraction, respectively. The optical transmission (T (%)) properties of the prepared MoSx samples were determined by ultraviolet–visible spectrophotometry. Cyclic voltammetry (CV) and Tafel-polarization measurements were performed to analyze the electrochemical properties and catalytic activities of the thin films for redox reactions. The FE-SEM results showed that the MoSx thin films were deposited uniformly on the ITO/PEN flexible substrates via the pulsed ECD method. The CV and Tafel-polarization curve measurements demonstrated that the deposited MoSx thin films exhibited excellent performances for the reduction of triiodide ions. The photoelectric conversion efficiency (PCE) of the DSSC produced with the pulsed ECD MoSx thin-film CE was examined by a solar simulator. In combination with a dye-sensitized TiO2 working electrode and an iodine-based electrolyte, the DSSC with the MoSx flexible CE showed a PCE of 4.39% under an illumination of AM 1.5 (100 mW cm−2). Thus, we report that the MoSx thin films are active catalysts for triiodide reduction. The MoSx thin films are prepared at room temperature and atmospheric pressure and in a simple and rapid manner. This is an important practical contribution to the production of flexible low-cost thin-film CEs based on plastic substrates. The MoSx thin films produced by pulsed ECD are good candidates for catalysts in flexible DSSCs. - Highlights: • We used indium tin oxide/polyethylene naphthalate (ITO/PEN) as a substrate. • Molybdenum sulfide (MoSx) thin films were deposited on ITO/PEN. • We used electrochemical deposition to deposit MoSx thin films on ITO/PEN. • The MoSx/ITO/PEN was used as a flexible counter electrode (CE) for DSSCs. • The DSSC with MoSx/ITO/PEN CE showed a photoelectric conversion efficiency of 4.39%

  9. Solution-processed highly efficient Cu2ZnSnSe4 thin film solar cells by dissolution of elemental Cu, Zn, Sn, and Se powders.

    Yang, Yanchun; Wang, Gang; Zhao, Wangen; Tian, Qingwen; Huang, Lijian; Pan, Daocheng

    2015-01-14

    Solution deposition approaches play an important role in reducing the manufacturing cost of Cu2ZnSnSe4 (CZTSe) thin film solar cells. Here, we present a novel precursor-based solution approach to fabricate highly efficient CZTSe solar cells. In this approach, low-cost elemental Cu, Zn, Sn, and Se powders were simultaneously dissolved in the solution of thioglycolic acid and ethanolamine, forming a homogeneous CZTSe precursor solution to deposit CZTSe nanocrystal thin films. Based on high-quality CZTSe absorber layer, pure selenide CZTSe solar cell with a photoelectric conversion efficiency of 8.02% has been achieved without antireflection coating. PMID:25494493

  10. Radial n-i-p structure SiNW-based microcrystalline silicon thin-film solar cells on flexible stainless steel

    Xie, Xiaobing; Zeng, Xiangbo; Yang, Ping; Li, Hao; Li, Jingyan; Zhang, Xiaodong; Wang, Qiming

    2012-01-01

    Radial n-i-p structure silicon nanowire (SiNW)-based microcrystalline silicon thin-film solar cells on stainless steel foil was fabricated by plasma-enhanced chemical vapor deposition. The SiNW solar cell displays very low optical reflectance (approximately 15% on average) over a broad range of wavelengths (400 to 1,100 nm). The initial SiNW-based microcrystalline (?c-Si:H) thin-film solar cell has an open-circuit voltage of 0.37 V, short-circuit current density of 13.36 mA/cm2, fill factor o...

  11. Design of a wideband multilayer grating spectrometer for the study of electronic structure of thin-film CIS solar cells

    A soft x-ray emission spectrometer equipped with a wideband Ni/C multilayer-coated laminar-type varied-line-spacing holographic grating is designed to analyze the electronic structure in thin-film copper indium selenide (CIS) solar cells nondestructively by soft x-ray emission spectroscopy. The spectrometer equipped with the multilayer grating thus designed allows us to detect the L emission lines of Cu, In, and Se simultaneously from a CIS absorber layer in the 13.5 keV range at a constant angle of incidence. (author)

  12. Transport properties of CuGaSe(2)-based thin-film solar cells as a function of absorber composition

    Rusu, M; Bar, M.; Fuertes Marrón, David; Lehmann, Sebastian; Schedel Niedrig, T.; Lux Steiner, M. Ch.

    2011-01-01

    The transport properties of thin-film solar cells based on wide-gap CuGaSe(2) absorbers have been investigated as a function of the bulk [Ga]/[Cu] ratio ranging from 1.01 to 1.33. We find that (i) the recombination processes in devices prepared from absorbers with a composition close to stoichiometry ([Ga]/[Cu] = 1.01) are strongly tunnelling assisted resulting in low recombination activation energies (E(a)) of approx. 0.95 eV in the dark and 1.36 eV under illumination. (ii) With an increasin...

  13. Study of alternative back contacts for thin film Cu2ZnSnSe4-based solar cells

    Oueslati, Souhaib; Brammertz, Guy; Buffiere, Marie; ElAnzeery, Hossam; Mangin, Denis; ElDaif, Ounsi; Touayar, Oualid; Koble, Christine; MEURIS, Marc; Poortmans, Jef

    2015-01-01

    Cu2ZnSnSe4 thin film solar cells are usually fabricated on a soda lime glass substrate with a molybdenum (Mo) back contact. It is suspected that degradation in electrical performance occurs due to the formation of a barrier between the absorber and Mo back contact. To overcome such degradation, Titanium Nitride (TiN), Titanium Tungsten (TiW), Chromium (Cr), Titanium (Ti) and Aluminum (Al) deposited on Mo-coated glass substrates are investigated as alternative back contact materials. Physical ...

  14. ZnO nanorod arrays for highly efficient thin film a-Si and micromorph solar cells

    Neykova, Neda; Hruška, Karel; Remeš, Zdeněk; Vaněček, Milan

    Roma : University of Roma Tor Vergata, 2012 - (DE Crescenzi, M.). s. 75-75 [International Conference on NANO-structures self-assembly - NANOSEA 2012 /4./. 25.06.2012-29.06.2012, S. Margherita di Pula - Sardinie] R&D Projects: GA ČR(CZ) GAP108/11/0937 EU Projects: European Commission(XE) 214134 - N2P Institutional research plan: CEZ:AV0Z10100521 Keywords : ZnO nanocolumns * thin film solar cells * EBL Subject RIV: BM - Solid Matter Physics ; Magnetism

  15. Plasmonic back contacts with non-ordered Ag nanostructures for light trapping in thin-film silicon solar cells

    Paetzold, Ulrich W., E-mail: u.paetzold@fz-juelich.de [IEK5-Photovoltaik, Forschungszentrum Juelich, D-52425 Juelich (Germany); Meier, Matthias, E-mail: ma.meier@fz-juelich.de [IEK5-Photovoltaik, Forschungszentrum Juelich, D-52425 Juelich (Germany); Moulin, Etienne, E-mail: e.moulin@fz-juelich.de [IEK5-Photovoltaik, Forschungszentrum Juelich, D-52425 Juelich (Germany); Smirnov, Vladimir, E-mail: v.smirnov@fz-juelich.de [IEK5-Photovoltaik, Forschungszentrum Juelich, D-52425 Juelich (Germany); Pieters, Bart E., E-mail: b.pieters@fz-juelich.de [IEK5-Photovoltaik, Forschungszentrum Juelich, D-52425 Juelich (Germany); Rau, Uwe, E-mail: u.rau@fz-juelich.de [IEK5-Photovoltaik, Forschungszentrum Juelich, D-52425 Juelich (Germany); Carius, Reinhard, E-mail: r.carius@fz-juelich.de [IEK5-Photovoltaik, Forschungszentrum Juelich, D-52425 Juelich (Germany)

    2013-05-15

    In this work, we investigate the light trapping of thin-film silicon solar cells which apply plasmonic Ag back contacts with non-ordered Ag nanostructures. The preparation, characterization and three-dimensional electromagnetic simulations of these back contacts with various distributions of non-ordered Ag nanostructures are presented. The measured reflectance spectra of the Ag back contacts with non-ordered nanostructures in air are well reproduced in reflectance spectra derived from the three-dimensional electromagnetic simulations of isolated nanostructures on Ag back contacts. The lightmatter interaction of these nanostructures is given by localized surface plasmons and, thus, the measured diffuse reflectance of the back contacts is attributed to plasmon-induced light scattering. A significant plasmonic light-trapping effect in n-i-p substrate-type ?c-Si:H thin-film solar cell prototypes which apply a Ag back contact with non-ordered nanostructures is identified when compared with flat reference solar cells.

  16. Plasmonic back contacts with non-ordered Ag nanostructures for light trapping in thin-film silicon solar cells

    In this work, we investigate the light trapping of thin-film silicon solar cells which apply plasmonic Ag back contacts with non-ordered Ag nanostructures. The preparation, characterization and three-dimensional electromagnetic simulations of these back contacts with various distributions of non-ordered Ag nanostructures are presented. The measured reflectance spectra of the Ag back contacts with non-ordered nanostructures in air are well reproduced in reflectance spectra derived from the three-dimensional electromagnetic simulations of isolated nanostructures on Ag back contacts. The lightmatter interaction of these nanostructures is given by localized surface plasmons and, thus, the measured diffuse reflectance of the back contacts is attributed to plasmon-induced light scattering. A significant plasmonic light-trapping effect in n-i-p substrate-type ?c-Si:H thin-film solar cell prototypes which apply a Ag back contact with non-ordered nanostructures is identified when compared with flat reference solar cells

  17. Radio Frequency Magnetron Sputtering Deposition of TiO2 Thin Films and Their Perovskite Solar Cell Applications

    Chen, Cong; Cheng, Yu; Dai, Qilin; Song, Hongwei

    2015-12-01

    In this work, we report a physical deposition based, compact (cp) layer synthesis for planar heterojunction perovskite solar cells. Typical solution-based synthesis of cp layer for perovskite solar cells involves low-quality of thin films, high-temperature annealing, non-flexible devices, limitation of large-scale production and that the effects of the cp layer on carrier transport have not been fully understood. In this research, using radio frequency magnetron sputtering (RFMS), TiO2 cp layers were fabricated and the thickness could be controlled by deposition time; CH3NH3PbI3 films were prepared by evaporation & immersion (E & I) method, in which PbI2 films made by thermal evaporation technique were immersed in CH3NH3I solution. The devices exhibit power conversion efficiency (PCE) of 12.1% and the photovoltaic performance can maintain 77% of its initial PCE after 1440 h. The method developed in this study has the capability of fabricating large active area devices (40 × 40 mm2) showing a promising PCE of 4.8%. Low temperature and flexible devices were realized and a PCE of 8.9% was obtained on the PET/ITO substrates. These approaches could be used in thin film based solar cells which require high-quality films leading to reduced fabrication cost and improved device performance.

  18. Absorptive carbon nanotube electrodes: consequences of optical interference loss in thin film solar cells.

    Tait, Jeffrey G; De Volder, Michaël F L; Cheyns, David; Heremans, Paul; Rand, Barry P

    2015-04-28

    A current bottleneck in the thin film photovoltaic field is the fabrication of low cost electrodes. We demonstrate ultrasonically spray coated multiwalled carbon nanotube (CNT) layers as opaque and absorptive metal-free electrodes deposited at low temperatures and free of post-deposition treatment. The electrodes show sheet resistance as low as 3.4 Ω □(-1), comparable to evaporated metallic contacts deposited in vacuum. Organic photovoltaic devices were optically simulated, showing comparable photocurrent generation between reflective metal and absorptive CNT electrodes for photoactive layer thickness larger than 600 nm when using archetypal poly(3-hexylthiophene) (P3HT) : (6,6)-phenyl C61-butyric acid methyl ester (PCBM) cells. Fabricated devices clearly show that the absorptive CNT electrodes display comparable performance to solution processed and spray coated Ag nanoparticle devices. Additionally, other candidate absorber materials for thin film photovoltaics were simulated with absorptive contacts, elucidating device design in the absence of optical interference and reflection. PMID:25811493

  19. Theoretical study of quaternary compounds as thin-film solar cell absorber

    Full text : Design of chalcogenide photovoltaic absorbers is carried out systematically through sequential cation mutation, from binary to ternary to quaternary compounds, using first-principles electronic structure calculations. Several universal trends are found for the ternary and two classes of quaternary chalcogenides. For example, the lowest-energy structure always has larger lattice constant a, smaller tetragonal distortion parameter ?=c/2a, and larger band gap than the metastable structures for common-row cation mutations. The band gap is reduced during the mutation. The band gap decreases from binary II-VI to ternary I-III-VI2 are mostly due to the p-d repulsion in the valence band, the decreases from ternary I-III-VI2 to quaternary I2-II-IV-VI4 chalcogenides are due to the downshift in the conduction band caused by the wavefunction localization on the group IV cation site. It was found that I2-II-IV-VI4 compounds are more stable in the kesterite structure, whereas the widely-assumed stannite structure reported in the literature is most likely due to partial disorder in the I-II layer of the kesterite phase. Among the derived quaternary compounds, Cu2ZnSnS4 (CZTS) is one of the ideal candidate absorber materials for thin-film solar cells with an optimal band gap, high absorption coefficient, abundant elemental components, and is adaptable to various growth techniques. It was performed a series of first-principles electronic structure calculations for CZTS. Also it was found that in the ground state kesterite structure, (i) the chemical potential region that CZTS can form is very small. Therefore, it will be very difficult to obtain high quality stoichiometric CZTS samples; (ii) The dominant p-type acceptor in CZTS is CuZn, however, the associated acceptor level is relatively high, suggesting that p-type doping in CZTS is more difficult than ternary compounds such as CuInSe2; (iii) The formation of the self-compensated defect pair [CuZn+ZnCu] will not lead to a strong carrier separation, and thus will not contribute the same beneficial effect observed in ternary chalcopyrite compounds; (iv) We predict that to avoid the aforementioned issues in (ii) and (iii), it will be optimal to grow the sample under Cu-poor/Zn-rich conditions, so VCu and ZnCu become the dominant defects in the system. However, in this case, non-equilibrium growth techniques may be required to avoid the formation of secondary phases. All predictions will be compared with available experiments

  20. UV micro-imprint patterning for tunable light trapping in p-i-n thin-film silicon solar cells

    Wang, Yanfeng; Zhang, Xiaodan; Han, Bing; Bai, Lisha; Zhao, Huixu; Yang, Fu; Liang, Junhui; Huang, Qian; Chen, Xinliang; Zhao, Ying

    2015-11-01

    In this paper, we used UV micro-imprint lithography periodic patterning combined with self-textured BZO films with a wide range of texture distributions for light trapping in thin-film silicon solar cells. It was found that the feature size of the periodic textures has a significant influence on the light trapping capacity of the glass substrate and the external quantum efficiency (EQE) of microcrystalline silicon (?c-Si:H) solar cells. Microcrystalline silicon solar cells, deposited on periodic textures of 5 ?m, showed an improved photocurrent density without any loss in the open-circuit voltage and fill factor; hence, resulting in an overall efficiency increase of 6.28%.

  1. Structural and optical properties of electrodeposited culnSe2 thin films for photovoltaic solar cells

    Optical an structural properties of electrodeposited copper indium diselenide, CulnSe2, thin films were studied for its application in photovoltaic devices. X-ray diffraction patterns showed that thin films were grown in chalcopyrite phase after suitable treatments. Values of Eg for the CulnSe2 thin films showed a dependence on the deposition potential as determined by optical measurements. (Author) 47 refs

  2. Thin-Film Solar Array Earth Orbit Mission Applicability Assessment

    Hoffman, David J.; Kerslake, Thomas W.; Hepp, Aloysius F.; Raffaelle, Ryne P.

    2002-10-01

    This is a preliminary assessment of the applicability and spacecraft-level impact of using very lightweight thin-film solar arrays with relatively large deployed areas for representative Earth orbiting missions. The most and least attractive features of thin-film solar arrays are briefly discussed. A simple calculation is then presented illustrating that from a solar array alone mass perspective, larger arrays with less efficient but lighter thin-film solar cells can weigh less than smaller arrays with more efficient but heavier crystalline cells. However, a proper spacecraft-level systems assessment must take into account the additional mass associated with solar array deployed area: the propellant needed to desaturate the momentum accumulated from area-related disturbance torques and to perform aerodynamic drag makeup reboost. The results for such an assessment are presented for a representative low Earth orbit (LEO) mission, as a function of altitude and mission life, and a geostationary Earth orbit (GEO) mission. Discussion of the results includes a list of specific mission types most likely to benefit from using thin-film arrays. NASA Glenn's low-temperature approach to depositing thin-film cells on lightweight, flexible plastic substrates is also briefly discussed to provide a perspective on one approach to achieving this enabling technology. The paper concludes with a list of issues to be addressed prior to use of thin-film solar arrays in space and the observation that with their unique characteristics, very lightweight arrays using efficient, thin-film cells on flexible substrates may become the best array option for a subset of Earth orbiting missions.

  3. Silicon nitride and intrinsic amorphous silicon double antireflection coatings for thin-film solar cells on foreign substrates

    Hydrogenated intrinsic amorphous silicon (a-Si:H) was investigated as a surface passivation method for crystalline silicon thin film solar cells on graphite substrates. The results of the experiments, including quantum efficiency and current density-voltage measurements, show improvements in cell performance. This improvement is due to surface passivation by an a-Si:H(i) layer, which increases the open circuit voltage and the fill factor. In comparison with our previous work, we have achieved an increase of 0.6% absolute cell efficiency for a 40 μm thick 4 cm2 aperture area on the graphite substrate. The optical properties of the SiNx/a-Si:H(i) stack were studied using spectroscopic ellipsometer techniques. Scanning transmission electron microscopy inside a scanning electron microscope was applied to characterize the cross section of the SiNx/a-Si:H(i) stack using focus ion beam preparation. - Highlights: • We report a 10.8% efficiency for thin-film silicon solar cell on graphite. • Hydrogenated intrinsic amorphous silicon was applied for surface passivation. • SiNx/a-Si:H(i) stacks were characterized by spectroscopic ellipsometer techniques. • Cross-section micrograph was obtained by scanning transmission electron microscopy. • Quantum efficiency and J-V measurements show improvements in the cell performance

  4. Silicon nitride and intrinsic amorphous silicon double antireflection coatings for thin-film solar cells on foreign substrates

    Li, Da; Kunz, Thomas [Bavarian Center for Applied Energy Research (ZAE Bayern), Division: Photovoltaics and Thermosensoric, Haberstr. 2a, 91058 Erlangen (Germany); Wolf, Nadine [Bavarian Center for Applied Energy Research (ZAE Bayern), Division: Energy Efficiency, Am Galgenberg 87, 97074 Wuerzburg (Germany); Liebig, Jan Philipp [Materials Science and Engineering, Institute I, University of Erlangen-Nuremberg, Martensstr. 5, 91058 Erlangen (Germany); Wittmann, Stephan; Ahmad, Taimoor; Hessmann, Maik T.; Auer, Richard [Bavarian Center for Applied Energy Research (ZAE Bayern), Division: Photovoltaics and Thermosensoric, Haberstr. 2a, 91058 Erlangen (Germany); Göken, Mathias [Materials Science and Engineering, Institute I, University of Erlangen-Nuremberg, Martensstr. 5, 91058 Erlangen (Germany); Brabec, Christoph J. [Bavarian Center for Applied Energy Research (ZAE Bayern), Division: Photovoltaics and Thermosensoric, Haberstr. 2a, 91058 Erlangen (Germany); Institute of Materials for Electronics and Energy Technology, University of Erlangen-Nuremberg, Martensstr. 7, 91058 Erlangen (Germany)

    2015-05-29

    Hydrogenated intrinsic amorphous silicon (a-Si:H) was investigated as a surface passivation method for crystalline silicon thin film solar cells on graphite substrates. The results of the experiments, including quantum efficiency and current density-voltage measurements, show improvements in cell performance. This improvement is due to surface passivation by an a-Si:H(i) layer, which increases the open circuit voltage and the fill factor. In comparison with our previous work, we have achieved an increase of 0.6% absolute cell efficiency for a 40 μm thick 4 cm{sup 2} aperture area on the graphite substrate. The optical properties of the SiN{sub x}/a-Si:H(i) stack were studied using spectroscopic ellipsometer techniques. Scanning transmission electron microscopy inside a scanning electron microscope was applied to characterize the cross section of the SiN{sub x}/a-Si:H(i) stack using focus ion beam preparation. - Highlights: • We report a 10.8% efficiency for thin-film silicon solar cell on graphite. • Hydrogenated intrinsic amorphous silicon was applied for surface passivation. • SiN{sub x}/a-Si:H(i) stacks were characterized by spectroscopic ellipsometer techniques. • Cross-section micrograph was obtained by scanning transmission electron microscopy. • Quantum efficiency and J-V measurements show improvements in the cell performance.

  5. Wide-spectrum Mg and Ga co-doped ZnO TCO thin films for solar cells grown via magnetron sputtering with H2 introduction

    Highlights: • Hydrogenated Mg and Ga co-doped ZnO thin films are obtained. • Low resistivity and high optical transmittances in wide spectrum range are achieved. • Solar cells with HMGZO layer present higher quantum efficiency. - Abstract: Wide-spectrum Mg and Ga co-doped ZnO transparent conductive oxide (TCO) thin films are deposited via magnetron sputtering at various H2 flow rates on glass substrates. The structural, electrical, and optical properties of MGZO thin films are investigated with different H2 flow rates. The experiment results show that the MGZO thin films are polycrystalline with a hexagonal wurtzite structure exhibiting a preferred (0 0 2) crystal plane orientation. The carrier concentration remarkably increases from 5.15 × 1019 cm−3 to 2.12 × 1020 cm−3 with increasing the H2 flow rate from 0 sccm to 4.0 sccm and then decreases when further increasing the H2 flow rate. The glass/MGZO thin film deposited at the H2 flow rate of 4.0 sccm exhibits the lowest resistivity of 1.96 × 10−3 Ω cm (film thickness d ∼ 548 nm) and an average transmittance (Ta) of 80.5% in the wavelength range from 340 nm to 1100 nm. Optical measurements indicate that the optical band gap (Eg) of MGZO thin films varies from 3.45 eV to 3.78 eV with adjusting H2 flow rate from 0 sccm to 12.0 sccm. The obtained MGZO thin films with an appropriate thickness are preliminarily applied in p–i–n type hydrogenated amorphous silicon (a-Si:H) thin film solar cells. The a-Si:H solar cell with MGZO layer presents higher quantum efficiency in the short wavelength region than that with GZO layer, resulting from widened optical band gap

  6. Thin-Film Photovoltaic Solar Array Parametric Assessment

    Hoffman, David J.; Kerslake, Thomas W.; Hepp, Aloysius F.; Jacobs, Mark K.; Ponnusamy, Deva

    2000-01-01

    This paper summarizes a study that had the objective to develop a model and parametrically determine the circumstances for which lightweight thin-film photovoltaic solar arrays would be more beneficial, in terms of mass and cost, than arrays using high-efficiency crystalline solar cells. Previous studies considering arrays with near-term thin-film technology for Earth orbiting applications are briefly reviewed. The present study uses a parametric approach that evaluated the performance of lightweight thin-film arrays with cell efficiencies ranging from 5 to 20 percent. The model developed for this study is described in some detail. Similar mass and cost trends for each array option were found across eight missions of various power levels in locations ranging from Venus to Jupiter. The results for one specific mission, a main belt asteroid tour, indicate that only moderate thin-film cell efficiency (approx. 12 percent) is necessary to match the mass of arrays using crystalline cells with much greater efficiency (35 percent multi-junction GaAs based and 20 percent thin-silicon). Regarding cost, a 12 percent efficient thin-film array is projected to cost about half is much as a 4-junction GaAs array. While efficiency improvements beyond 12 percent did not significantly further improve the mass and cost benefits for thin-film arrays, higher efficiency will be needed to mitigate the spacecraft-level impacts associated with large deployed array areas. A low-temperature approach to depositing thin-film cells on lightweight, flexible plastic substrates is briefly described. The paper concludes with the observation that with the characteristics assumed for this study, ultra-lightweight arrays using efficient, thin-film cells on flexible substrates may become a leading alternative for a wide variety of space missions.

  7. Ecofriendly and Nonvacuum Electrostatic Spray-Assisted Vapor Deposition of Cu(In,Ga)(S,Se)2 Thin Film Solar Cells.

    Hossain, Md Anower; Wang, Mingqing; Choy, Kwang-Leong

    2015-10-14

    Chalcopyrite Cu(In,Ga)(S,Se)2 (CIGSSe) thin films have been deposited by a novel, nonvacuum, and cost-effective electrostatic spray-assisted vapor deposition (ESAVD) method. The generation of a fine aerosol of precursor solution, and their controlled deposition onto a molybdenum substrate, results in adherent, dense, and uniform Cu(In,Ga)S2 (CIGS) films. This is an essential tool to keep the interfacial area of thin film solar cells to a minimum value for efficient charge separation as it helps to achieve the desired surface smoothness uniformity for subsequent cadmium sulfide and window layer deposition. This nonvacuum aerosol based approach for making the CIGSSe film uses environmentally benign precursor solution, and it is cheaper for producing solar cells than that of the vacuum-based thin film solar technology. An optimized CIGSSe thin film solar cell with a device configuration of molybdenum-coated soda-lime glass substrate/CIGSSe/CdS/i-ZnO/AZO shows the photovoltaic (j-V) characteristics of Voc=0.518 V, jsc=28.79 mA cm(-2), fill factor=64.02%, and a promising power conversion efficiency of η=9.55% under simulated AM 1.5 100 mW cm(-2) illuminations, without the use of an antireflection layer. This demonstrates the potential of ESAVD deposition as a promising alternative approach for making thin film CIGSSe solar cells at a lower cost. PMID:26390182

  8. Fabrication and evaluation of CdS/PbS thin film solar cell by chemical bath deposition technique

    Saikia, Dulen, E-mail: dulen.s@rediffmail.com; Phukan, Pallabi

    2014-07-01

    A solar cell with the structure glass/SnO{sub 2}/CdS/PbS/HgTe has been fabricated where both window (CdS) and absorber (PbS) layers were deposited by a chemical bath deposition technique which is completely free from any complexing agents. The films were prepared by in-situ thermolysis of precursors confined in polyvinyl alcohol matrix (PVA). As the method is free of any complexing agent, hence no need to control the pH of the solution. The as-prepared films were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and UV–Vis absorption spectroscopy. The surface morphology clearly shows that as synthesized CdS/PVA and PbS/PVA thin films were nanostructured, almost homogeneous, without any pinholes or cracks and covered the substrate well. The photovoltaic parameters of the cell were measured with the Keithley 2400 source meter under one sun illumination and efficiency of the cell was found to be 1.668%. - Highlights: • Polyvinyl alcohol matrix-capped PbS thin film from a complexing agent free system • Fabrication of CdS/PbS solar cell based on chemical bath deposition technique • An efficiency of 1.668% is achieved under one SUN illumination.

  9. A glass thinning and texturing method for light incoupling in thin-film polycrystalline silicon solar cells application

    Cui, Hongtao; Campbell, Patrick R. [School of Photovoltaic and Renewable Energy Engineering, UNSW, Sydney NSW 2052 (Australia)

    2012-08-15

    For polycrystalline silicon (poly-Si) thin-film solar cells on {proportional_to}3 mm borosilicate glass, glass thinning reduces the glass absorption and light leaking to neighbouring cells; the glass texturing of the sun-facing side suppresses reflection. In this Letter, a labour-free wet etching method is developed to texture and thin the glass at the same time in contrast to conventionally separated labour-intensive glass thinning and texturing processes. For 2 cm{sup 2} size poly-Si thin-film solar cells on glass superstrate, this wet etching successfully thins down the glass from 3 mm to 0.5 mm to check the ultimate benefit of the process and introduces a large micron texture on the sun-facing glass surface. The process enhances J{sub sc} by 6.3% on average, with the optimal J{sub sc} enhancement of 8%, better than the value of 4.6% found in the literature. This process also reduces the loss in external quantum efficiency (EQE loss), which is due to light leaking to neighbouring cells, dramatically. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. Analysis of radiation resistance of InGaP/GaAs dual-junction thin-film space solar cell

    Thin-film III-V multi-junction solar cells can realize the advantages of being high-efficiency and light-weight, as such these cells meets the requirement for higher specific power and lower stowage volume solar panels. Here we report the development results of an InGaP/GaAs thin-film dual-junction (TF2J) solar cell. In this paper, we study the radiation resistance of the TF2J cells with efficiency of 20-23% under AM0.1 sun at 25degC. The cells were subjected to proton irradiation with an energy range of 100keV-10MeV. The results were compared with the radiation resistance of a conventional InGaP/GaAs/Ge triple-junction (3J) cell. In the proton energy range of 200-400keV, radiation resistance of the TF2J cell is superior to that of the 3J cell. Particularly, the 1sc of the TF2J cell is significantly higher than that of the 3J cell after exposure to 380keV protons, which results in higher remaining factor of Pmax for the TF2J cell. In additions, Voc of the cells after the irradiations are almost equivalent, even though the TF2J cell is a dual-junction structure. The higher 1sc of the TF2J cell after irradiation is due to higher radiation resistance of the GaAs subcell according to the comparison of the spectral response. (author)

  11. Modification of opto-electronic properties of ZnO by incorporating metallic tin for buffer layer in thin film solar cells

    In this report, the effect of incorporation of metallic tin (Sn) on opto-electronic properties of ZnO thin films is presented. ZnO thin films were deposited through ‘automated chemical spray pyrolysis’ (CSP) technique; later different quantities of ‘Sn’ were evaporated on it and subsequently annealed. Vacuum annealing showed a positive effect on crystallinity of films. Creation of sub band gap levels due to ‘Sn’ diffusion was evident from the absorption and PL spectra. The tin incorporated films showed good photo response in visible region. Tin incorporated ZnO thin films seem to satisfy the desirable criteria for buffer layer in thin film solar cells

  12. Influence of intermediate layers on the surface condition of laser crystallized silicon thin films and solar cell performance

    The intermediate layer (IL) between glass substrate and silicon plays a significant role in the optimization of multicrystalline liquid phase crystallized silicon thin film solar cells on glass. This study deals with the influence of the IL on the surface condition and the required chemical surface treatment of the crystallized silicon (mc-Si), which is of particular interest for a-Si:H heterojunction thin film solar cells. Two types of IL were investigated: sputtered silicon nitride (SiN) and a layer stack consisting of silicon nitride and silicon oxide (SiN/SiO). X-ray photoelectron spectroscopy measurements revealed the formation of silicon oxynitride (SiOxNy) or silicon oxide (SiO2) layers at the surface of the mc-Si after liquid phase crystallization on SiN or SiN/SiO, respectively. We propose that SiOxNy formation is governed by dissolving nitrogen from the SiN layer in the silicon melt, which segregates at the crystallization front during crystallization. This process is successfully hindered, when additional SiO layers are introduced into the IL. In order to achieve solar cell open circuit voltages above 500 mV, a removal of the formed SiOxNy top layer is required using sophisticated cleaning of the crystallized silicon prior to a-Si:H deposition. However, solar cells crystallized on SiN/SiO yield high open circuit voltage even when a simple wet chemical surface treatment is applied. The implementation of SiN/SiO intermediate layers facilitates the production of mesa type solar cells with open circuit voltages above 600 mV and a power conversion efficiency of 10%

  13. Dual-Layer Nanostructured Flexible Thin-Film Amorphous Silicon Solar Cells with Enhanced Light Harvesting and Photoelectric Conversion Efficiency.

    Lin, Yinyue; Xu, Zhen; Yu, Dongliang; Lu, Linfeng; Yin, Min; Tavakoli, Mohammad Mahdi; Chen, Xiaoyuan; Hao, Yuying; Fan, Zhiyong; Cui, Yanxia; Li, Dongdong

    2016-05-01

    Three-dimensional (3-D) structures have triggered tremendous interest for thin-film solar cells since they can dramatically reduce the material usage and incident light reflection. However, the high aspect ratio feature of some 3-D structures leads to deterioration of internal electric field and carrier collection capability, which reduces device power conversion efficiency (PCE). Here, we report high performance flexible thin-film amorphous silicon solar cells with a unique and effective light trapping scheme. In this device structure, a polymer nanopillar membrane is attached on top of a device, which benefits broadband and omnidirectional performances, and a 3-D nanostructure with shallow dent arrays underneath serves as a back reflector on flexible titanium (Ti) foil resulting in an increased optical path length by exciting hybrid optical modes. The efficient light management results in 42.7% and 41.7% remarkable improvements of short-circuit current density and overall efficiency, respectively. Meanwhile, an excellent flexibility has been achieved as PCE remains 97.6% of the initial efficiency even after 10 000 bending cycles. This unique device structure can also be duplicated for other flexible photovoltaic devices based on different active materials such as CdTe, Cu(In,Ga)Se2 (CIGS), organohalide lead perovskites, and so forth. PMID:27052357

  14. Polymer assisted solution processing of Ti-doped indium oxide transparent conducting thin films for organic solar cells

    Highlights: • Polymer assisted solution process. • Ti-doped indium oxide (TIO) transparent conducting films. • Replacement of sputtered ITO with polymer-assisted-solution-coated TIO films. • High mobility transparent conducting films. • Application of polymer-assisted-solution-coated TIO films to organic solar cells. - Abstract: We report the preparation and evaluation of Ti-doped indium oxide (TIO) transparent conducting films by a polymer-assisted solution (PAS) process, as well as the evaluation of this type of film as a transparent cathode in an inverted organic solar cell (IOCS). Both Ti- and In-PASs have been synthesized by coordinating Ti- and In-anionic complexes with polyethyleneimine. The final TIO–PAS was formed by mixing Ti-PAS into In-PAS with a Ti concentration between 1 at.% and 7 at.%. The TIO–PAS was spin-coated onto glass substrates to form uniform thin films of Ti-doped indium oxide, which were then annealed at high temperature. The optimum Ti concentration to achieve the best electrical and optical properties of PAS–TIO films was found to be 3 at.%. With the film thickness of 650 nm, PAS–TIO films had a sheet resistance of 65 Ω/sq and an optical transmittance greater than 85%. The feasibility of PAS-coated TIO thin film as a transparent electrode was evaluated by applying it to the fabrication of IOSCs, which showed the energy conversion efficiency of 4.60%

  15. Evaluation of electrical and optical characteristics of ZnO/CdS/CIS thin film solar cell

    Hadi, Zarei; Rasoul, Malekfar

    2016-02-01

    In this study, device modeling and simulation are conducted to explain the effects of each layer thickness and temperature on the performance of ZnO/CdS/CIS thin film solar cells. Also, the thicknesses of the CIS and CdS absorber layers are considered in this work theoretically and experimentally. The calculations of solar cell performances are based on the solutions of the well-known three coupling equations: the continuity equation for holes and electrons and the Poisson equation. Our simulated results show that the efficiency increases by reducing the CdS thickness. Increasing the CIS thickness can increase the efficiency but it needs more materials. The efficiency is more than 19% for a CIS layer with a thickness of 2 μm. CIS nanoparticles are prepared via the polyol route and purified through centrifugation and precipitation processes. Then nanoparticles are dispersed to obtain stable inks that could be directly used for thin-film deposition via spin coating. We also obtain x-ray diffraction (XRD) peak intensities and absorption spectra for CIS experimentally. Finally, absorption spectra for the CdS window layer in several deposition times are investigated experimentally.

  16. Thin film absorber for a solar collector

    Wilhelm, William G. (Cutchogue, NY)

    1985-01-01

    This invention pertains to energy absorbers for solar collectors, and more particularly to high performance thin film absorbers. The solar collectors comprising the absorber of this invention overcome several problems seen in current systems, such as excessive hardware, high cost and unreliability. In the preferred form, the apparatus features a substantially rigid planar frame with a thin film window bonded to one planar side of the frame. An absorber in accordance with the present invention is comprised of two thin film layers that are sealed perimetrically. In a preferred embodiment, thin film layers are formed from a metal/plastic laminate. The layers define a fluid-tight planar envelope of large surface area to volume through which a heat transfer fluid flows. The absorber is bonded to the other planar side of the frame. The thin film construction of the absorber assures substantially full envelope wetting and thus good efficiency. The window and absorber films stress the frame adding to the overall strength of the collector.

  17. The effect of dopant concentration on properties of transparent conducting Al-doped ZnO thin films for efficient Cu2ZnSnS4 thin-film solar cells prepared by electrodeposition method

    Mkawi, E. M.; Ibrahim, K.; Ali, M. K. M.; Farrukh, M. A.; Mohamed, A. S.

    2015-11-01

    Al-doped ZnO (AZO) thin films were potentiostatically deposited on indium tin oxide substrates. The influence of the doping level of the ZnO:Al films was investigated. The results of the X-ray diffraction and scanning electron microscopy analysis revealed that the structural properties of the AZO films were found polycrystalline with a hexagonal wurtzite-type structure along the (002) plane. The grain size of the AZO films was observed as approximately 3 μm in the film doping with 4 mol% ZnO:Al concentration. The thin films also exhibited an optical transmittance as high as 90 % in the wavelength range of 100-1,000 nm. The optical band gap increased from 3.33 to 3.45 eV. Based on the Hall studies, the lowest resistivity (4.78 × 10-3 Ω cm) was observed in the film doping with 3 mol% ZnO:Al concentration. The sheet resistant, carrier concentration and Hall mobility values were found as 10.78 Ω/ square, 9.03 × 1018 cm-3 and 22.01 cm2/v s, respectively, which showed improvements in the properties of AZO thin films. The ZnO:Al thin films were used as a buffer layer in thin-film solar cells with the structure of soda-lime glass/Mo/Cu2ZnSnS4/ZnS/ZnO/Al grid. The best solar cell efficiency was 2.3 % with V OC of 0.430 V, J SC of 8.24 mA cm-2 and FF of 68.1 %.

  18. Non-toxic and environmentally friendly route for preparation of copper indium sulfide based thin film solar cells

    Sankir, Nurdan Demirci, E-mail: nsankir@etu.edu.tr; Aydin, Erkan; Ugur, Esma; Sankir, Mehmet

    2015-08-15

    Highlights: • Substrate structure of spray pyrolyzed CuInS{sub 2}/In{sub 2}S{sub 3} heterojunction solar cells. • Low cost and environmentally friendly fabrication of CuInS{sub 2} based solar cells. • Low RF power deposition of TCO layer. • AZO–Ag–AZO sandwich structure. • Effect of the thickness of buffer layer on the photovoltaic performance. - Abstract: In this study, copper based thin film solar cells with substrate structure have been built via spray pyrolysis method. Toxic material usage was avoided during the material deposition and the post-treatment steps. Novel device configuration of Mo/CuInS{sub 2}/In{sub 2}S{sub 3}/ZnO/AZO–Ag–AZO was studied as a function of the In{sub 2}S{sub 3} buffer layer thickness. In order to utilize the zinc oxide (ZnO) and aluminum doped zinc oxide (AZO) transparent conductive layers, deposited by physical vapor deposition (PVD), on top of the spray pyrolyzed thin films, the RF power was lowered to 30 W. Although this minimized the unwanted penetration of the highly energetic particles, created during PVD process, sheet resistivity of the AZO films increased enormously. Hence very thin silver layer has been deposited between two AZO films. This resulted the decrease in the sheet resistivity more than 10{sup 6} times. Electrical measurements under illumination revealed that short circuit current density (J{sub sc}), open circuit voltage (V{sub oc}), fill factor (FF) and efficiency (η) of the Mo/CuInS{sub 2}/In{sub 2}S{sub 3}/ZnO/AZO–Ag–AZO type solar cells increased with increasing the thickness of the In{sub 2}S{sub 3} layer. The maximum J{sub sc} of 9.20 mA/cm{sup 2}, V{sub oc} of 0.43 V, FF of 0.44 have been observed for the 0.94 μm-thick In{sub 2}S{sub 3} layer. Extraordinarily thick buffer layer provided better diffusion barrier between the absorber and the TCO layers and also resulted better photosensitivity. These could be the key factors to produce substrate configuration of the spray pyrolyzed thin film solar cells.

  19. Non-toxic and environmentally friendly route for preparation of copper indium sulfide based thin film solar cells

    Highlights: Substrate structure of spray pyrolyzed CuInS2/In2S3 heterojunction solar cells. Low cost and environmentally friendly fabrication of CuInS2 based solar cells. Low RF power deposition of TCO layer. AZOAgAZO sandwich structure. Effect of the thickness of buffer layer on the photovoltaic performance. - Abstract: In this study, copper based thin film solar cells with substrate structure have been built via spray pyrolysis method. Toxic material usage was avoided during the material deposition and the post-treatment steps. Novel device configuration of Mo/CuInS2/In2S3/ZnO/AZOAgAZO was studied as a function of the In2S3 buffer layer thickness. In order to utilize the zinc oxide (ZnO) and aluminum doped zinc oxide (AZO) transparent conductive layers, deposited by physical vapor deposition (PVD), on top of the spray pyrolyzed thin films, the RF power was lowered to 30 W. Although this minimized the unwanted penetration of the highly energetic particles, created during PVD process, sheet resistivity of the AZO films increased enormously. Hence very thin silver layer has been deposited between two AZO films. This resulted the decrease in the sheet resistivity more than 106 times. Electrical measurements under illumination revealed that short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF) and efficiency (?) of the Mo/CuInS2/In2S3/ZnO/AZOAgAZO type solar cells increased with increasing the thickness of the In2S3 layer. The maximum Jsc of 9.20 mA/cm2, Voc of 0.43 V, FF of 0.44 have been observed for the 0.94 ?m-thick In2S3 layer. Extraordinarily thick buffer layer provided better diffusion barrier between the absorber and the TCO layers and also resulted better photosensitivity. These could be the key factors to produce substrate configuration of the spray pyrolyzed thin film solar cells

  20. Fabrication of Cu2ZnSnS4 thin films using oxides nanoparticles ink for solar cell

    Chen, Guilin; Yuan, Chenchen; Liu, Jiwan; Huang, Zhigao; Chen, Shuiyuan; Liu, Weifeng; Jiang, Guoshun; Zhu, Changfei

    2015-02-01

    Oxides nanoparticles-based process is one of the successful approaches to CuIn1-xGaxSe2 (CIGS) formation. To explore systematically the possibility of application of the similar methods to high quality Cu2ZnSnS4 (CZTS), an oxides nanoparticles-based process for preparation of CZTS films is described. The CZTS films are prepared by sulfurizing oxides precursor. Thermodynamic appreciation of sulfurization of oxides precursor is first studied. The development of the CZTS formation with increasing temperature is also investigated. Through optimizing the sulfurization, phase-pure CZTS films with very large grains are obtained. The loss of tin can be avoided, due to the stability of oxides. Finally, preliminary CZTS thin-film solar cells with efficiencies of 1.47% have been fabricated. This study provides basis for low-cost and large area CZTS solar cells.

  1. Pulsed electrically detected magnetic resonance study of spin relaxation and recombination in thin-film silicon solar cells

    Fehr, Matthias; Behrends, Jan; Schnegg, Alexander; Lips, Klaus; Rech, Bernd [Helmholtz-Zentrum Berlin, Silizium Photovoltaik, Berlin (Germany); Astakhov, Oleksander; Finger, Friedhelm [Forschungszentrum Juelich (Germany). IEF-5 Photovoltaik

    2009-07-01

    We have investigated the influence of paramagnetic states on electronic transport processes in thin-film pin solar cells with pulsed Electrically Detected Magnetic Resonance (pEDMR) at X-Band frequency and low temperature (10 K). The solar cells consist of an intrinsic microcrystalline absorber layer and amorphous or microcrystalline n/p contacting layers. In addition to the identification of the participating paramagnetic centres by their g-factors, pEDMR can be used to study the dynamics of the electronic processes in detail. We present measurements of modified EPR pulse sequences in order to identify the dominating relaxation mechanisms within correlated solid-state spin-pairs. By this technique a monitoring of the spin and charge motion is possible. In the outlook we present measurements of the electron spin echo envelope and critically discuss modulations in terms of dipolar coupling within the spin-pairs or hyperfine couplings to surrounding nuclei.

  2. Easily accessible polymer additives for tuning the crystal-growth of perovskite thin-films for highly efficient solar cells

    Dong, Qingqing; Wang, Zhaowei; Zhang, Kaicheng; Yu, Hao; Huang, Peng; Liu, Xiaodong; Zhou, Yi; Chen, Ning; Song, Bo

    2016-03-01

    For perovskite solar cells (Pero-SCs), one of the key issues with respect to the power conversion efficiency (PCE) is the morphology control of the perovskite thin-films. In this study, an easily-accessible additive polyethylenimine (PEI) is utilized to tune the morphology of CH3NH3PbI3-xClx. With addition of 1.00 wt% of PEI, the smoothness and crystallinity of the perovskite were greatly improved, which were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). A summit PCE of 14.07% was achieved for the p-i-n type Pero-SC, indicating a 26% increase compared to those of the devices without the additive. Both photoluminescence (PL) and alternating current impedance spectroscopy (ACIS) analyses confirm the efficiency results after the addition of PEI. This study provides a low-cost polymer additive candidate for tuning the morphology of perovskite thin-films, and might be a new clue for the mass production of Pero-SCs.For perovskite solar cells (Pero-SCs), one of the key issues with respect to the power conversion efficiency (PCE) is the morphology control of the perovskite thin-films. In this study, an easily-accessible additive polyethylenimine (PEI) is utilized to tune the morphology of CH3NH3PbI3-xClx. With addition of 1.00 wt% of PEI, the smoothness and crystallinity of the perovskite were greatly improved, which were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). A summit PCE of 14.07% was achieved for the p-i-n type Pero-SC, indicating a 26% increase compared to those of the devices without the additive. Both photoluminescence (PL) and alternating current impedance spectroscopy (ACIS) analyses confirm the efficiency results after the addition of PEI. This study provides a low-cost polymer additive candidate for tuning the morphology of perovskite thin-films, and might be a new clue for the mass production of Pero-SCs. Electronic supplementary information (ESI) available: J-V curves & characteristics of Pero-SCs, UV-vis spectra and AFM images. See DOI: 10.1039/c6nr00206d

  3. Ultra-Lightweight Hybrid Thin-Film Solar Cells: A Survey of Enabling Technologies for Space Power Applications

    Hepp, Aloysius F.; McNatt, Jeremiah S.; Bailey, Sheila G.; Dickman, John E.; Raffaelle, Ryne P.; Landi, Brian J.; Anctil, Annick; DiLeo, Roberta; Jin, Michael H.-C.; Lee, Chung-Young; Friske, Theresa J.; Sun, Sam-S.; Zhang, Cheng; Choi, S.; Ledbetter, Abram; Seo, Kang; Bonner, Carl E.; Banger, Kulbinder K.; Castro, Stephanie L.; Rauh, David

    2007-01-01

    The development of hybrid inorganic/organic thin-film solar cells on flexible, lightweight, space-qualified, durable substrates provides an attractive solution for fabricating solar arrays with high mass specific power (W/kg). Next generation thin-film technologies may well involve a revolutionary change in materials to organic-based devices. The high-volume, low-cost fabrication potential of organic cells will allow for square miles of solar cell production at one-tenth the cost of conventional inorganic materials. Plastic solar cells take a minimum of storage space and can be inflated or unrolled for deployment. We will explore a cross-section of in-house and sponsored research efforts that aim to provide new hybrid technologies that include both inorganic and polymer materials as active and substrate materials. Research at University of Texas at Arlington focuses on the fabrication and use of poly(isothianaphthene-3,6-diyl) in solar cells. We describe efforts at Norfolk State University to design, synthesize and characterize block copolymers. A collaborative team between EIC Laboratories, Inc. and the University of Florida is investigating multijunction polymer solar cells to more effectively utilize solar radiation. The National Aeronautics and Space Administration (NASA)/Ohio Aerospace Institute (OAI) group has undertaken a thermal analysis of potential metallized substrates as well as production of nanoparticles of CuInS2 and CuInSe2 in good yield at moderate temperatures via decomposition of single-source precursors. Finally, preliminary work at the Rochester Institute of Technology (R.I.T.) to assess the impact on performance of solar cells of temperature and carbon nanotubes is reported. Technologies that must be developed to enable ultra-lightweight solar arrays include: monolithic interconnects, lightweight array structures, and new ultra-light support and deployment mechanisms. For NASA applications, any solar cell or array technology must not only meet weight and AMO efficiency goals, but also must be durable enough to survive launch conditions and space environments.

  4. Effect of load voltage on thin film cuprous sulfide: Cadmium sulfide solar cells thermally cycled in a simulated space environment

    Smithrick, J. J.; Thomas, R. D.

    1971-01-01

    Thin-film Cu2S-CdS solar cells, loaded at various fixed values of load resistance, were thermally cycled for 1429 cycles in a simulated space environment. Cell performance was measured under controlled conditions in air before and after thermal cycling. These data were used to determine the effect of load voltage on cell performance. The performance of the cells was relatively independent of load voltage up to about 0.39 volt. This appears to be a threshold voltage, beyond which there was a significant loss in cell performance. Fortunately, this threshold voltage appears to be sufficiently higher than the maximum power voltage of 0.33 volt so that it can be avoided in most applications.

  5. Loss mechanisms influence on Cu2ZnSnS4/CdS-based thin film solar cell performance

    Courel, Maykel; Andrade-Arvizu, J. A.; Vigil-Galán, O.

    2015-09-01

    One of the most important issues in kesterite Cu2ZnSnS4 (CZTS)-based thin film solar cells is low open circuit voltage, which is mainly related to loss mechanisms that take place in both CZTS bulk material and CdS/CZTS interface. A device model for CZTS/CdS solar cell which takes into account loss mechanisms influence on solar cell performance is presented. The simulation results showed that our model is able to reproduce experimental observations reported for CZTS/CdS-based solar cells with the highest conversion efficiencies, measured under room temperature and AM1.5 intensity. The comparison of simulation results to experimental observations demonstrated that among the different loss mechanisms, trap-assisted tunneling losses are the major hurdle to boost open circuit voltage. Under this loss mechanism, a solar cell efficiency enhancement up to 10.2% with CdS donor concentration decrease was reached. Finally, the possible path toward a further solar cell efficiency improvement is discussed.

  6. Estimation of local built-in potential of amorphous silicon thin-film solar cells by Kelvin force microscopy

    Itoh, Takashi; Ito, Takanori; Kuriyama, Hiroshi; Nonomura, Shuichi

    2016-04-01

    The local surface potential of pin-type hydrogenated amorphous silicon (a-Si:H) thin-film solar cells has been evaluated by Kelvin force microscopy (KFM). We have also estimated the local built-in potential of the solar cells by KFM. In the surface morphology image of the solar cells, large convex grains related to the textured structure of the substrate were found. The surface potential distribution related to the surface morphology was observed in the solar cells. A similar surface potential distribution was also found in an n-type hydrogenated microcrystalline Si (µc-Si:H) film. The surface potential of the solar cells was not the same as that of the n-type film. The difference in average surface potential between the n-type hydrogenated microcrystalline Si (µc-Si:H) film and the solar cells increased with increasing built-in potential. The difference in local surface potential on large convex grains was smaller than that in the region between the large convex grains.

  7. Development of a rapid thermal annealing process for polycrystalline silicon thin-film solar cells on glass

    In this report, we discuss the influence of rapid thermal annealing (RTA) on the performance of polycrystalline Si (poly-Si) thin-film solar cells on glass where the poly-Si layers are differently prepared. The first part presents a comprehensive study of RTA treatments on poly-Si thin-films made by solid phase crystallization (SPC) (standard material of CSG Solar AG, Thalheim). By varying both plateau temperature (up to 1050 deg. C) and duration (up to 1000 s) of the annealing profile, we determined the parameters for a maximum open-circuit voltage (VOC). In addition, we applied our standard plasma hydrogenation treatment in order to passivate the remaining intra-grain defects and grain boundaries by atomic hydrogen resulting in a further increase of VOC. We found, that the preceding RTA treatment increases the effect of hydrogenation already at comparable low RTA temperatures. The effect on hydrogenation increases significantly with RTA temperature. In a second step we investigated the effect of the RTA and hydrogenation on large-grained poly-Si films based on the epitaxial thickening of poly-Si seed layers.

  8. Cu(In,Ga)S2, Thin-Film Solar Cells Prepared by H2S Sulfurization of CuGa-In Precursor

    Dhere, Neelkanth G.; Kulkarni, Shashank R.; Chavan, Sanjay S.; Ghongadi, Shantinath R.

    2005-01-01

    Thin-film CuInS2 solar cell is the leading candidate for space power because of bandgap near the optimum value for AM0 solar radiation outside the earth's atmosphere, excellent radiation hardness, and freedom from intrinsic degradation mechanisms unlike a-Si:H cells. Ultra-lightweight thin-film solar cells deposited on flexible polyimide plastic substrates such as Kapton(trademark), Upilex(trademark), and Apical(trademark) have a potential for achieving specific power of 1000 W/kg, while the state-of-art specific power of the present day solar cells is 66 W/kg. This paper describes the preparation of Cu-rich CuIn(sub 1-x)Ga(sub x)S(sub 2) (CIGS2) thin films and solar cells by a process of sulfurization of CuGa-In precursor similar to that being used for preparation of large-compact-grain CuIn(sub 1-x)Ga(sub x)Se2 thin films and efficient solar cells at FSEC PV Materials Lab.

  9. Development of natively textured surface hydrogenated Ga-doped ZnO-TCO thin films for solar cells via magnetron sputtering

    Highlights: ? Natively textured surface hydrogenated gallium-doped zinc oxide (HGZO) thin films have been deposited via magnetron sputtering on glass substrates. ? The directly deposited HGZO thin films present rough crater-type surface morphology. ? Typical HGZO thin film exhibits a high electron mobility of 41.3 cm2/V s and a relative low sheet resistance of ?7.0 ?. ? These HGZO thin films have high optical transmittances in the visible and near infrared region (?3801100 nm). ? A gradient H2 growth method for fabricating HGZO thin films has been proposed in magnetron sputtering process. - Abstract: The main purposes are to obtain high quality transparent conductive oxide (TCO) based on zinc oxide (ZnO) thin films with high optical transparency in the visible and near infrared spectral range, high electrical conductivity and good light-scattering capability to enhance the path of the light inside the Si-based thin film solar cells. Natively textured surface hydrogenated gallium-doped ZnO (HGZO) thin films have been deposited via pulsed direct current (DC) magnetron sputtering on glass substrates at a substrate temperature of 553 K. These natively textured HGZO thin films exhibit high optical transmittance (over 80%) in the visible and near infrared region (? = 3801100 nm) and excellent electrical properties. The optimized HGZO thin film with crater-type textured surface obtained at the hydrogen flow rate of ?2.0 sccm exhibits a high electron mobility of 41.3 cm2/V s and a relatively low sheet resistance of ?7.0 ?. The influences of hydrogen flow rates on the surface morphology, electrical and optical properties of HGZO thin films were investigated in detail. In addition, we put forward a method of gradient H2 growth technique for fabricating HGZO thin films so as to obtain rough surface structure with good light-scattering capability and high electrical conductivity. Crater-like surface feature size and optical transmittance can be improved through gradient H2 growth technique.

  10. CdTe thin film solar cells produced using a chamberless inline process via metalorganic chemical vapour deposition

    Cd1−xZnxS and CdTe:As thin films were deposited using a recently developed chamberless inline process via metalorganic chemical vapour deposition (MOCVD) at atmospheric pressure and assessed for fabrication of CdTe photovoltaic (PV) solar cells. Initially, CdS and Cd1−xZnxS coatings were applied onto 15 × 15 cm2 float glass substrates, characterised for their optical properties, and then used as the window layer in CdTe solar cells which were completed in a conventional MOCVD (batch) reactor. Such devices provided best conversion efficiency of 13.6% for Cd0.36Zn0.64S and 10% for CdS which compare favourably to the existing baseline MOCVD (batch reactor) devices. Next, sequential deposition of Cd0.36Zn0.64S and CdTe:As films was realised by the chamberless inline process. The chemical composition of a 1 μm CdTe:As/150 nm Cd0.36Zn0.64S bi-layer was observed via secondary ions mass spectroscopy, which showed that the key elements are uniformly distributed and the As doping level is suitable for CdTe device applications. CdTe solar cells formed using this structure provided a best efficiency of 11.8% which is promising for a reduced absorber thickness of 1.25 μm. The chamberless inline process is non-vacuum, flexible to implement and inherits from the legacy of MOCVD towards doping/alloying and low temperature operation. Thus, MOCVD enabled by the chamberless inline process is shown to be an attractive route for thin film PV applications. - Highlights: • CdS, CdZnS and CdTe thin films grown by a chamberless inline process • The inline films assessed for fabricating CdTe solar cells • 13.6% conversion efficiency obtained for CdZnS/CdTe cells

  11. Quantitative analysis of spatially resolved electroluminescence of Cu(In,Ga)Se2 and a-Si:H thin-film solar cells and modules0

    Tran, Thi-Minh-Hang

    2015-01-01

    Electroluminescence (EL) is the reciprocal process of the standard operational mode of a solar cell. EL imaging technique allows a fast detection of defects in solar cells and modules with low noise and high resolution. Recently, EL has become one of the most commonly used characterization tools for photovoltaic devices. There has been a significant amount of research into the interpretation and analysis of EL of silicon wafers, solar cells and modules, but very little, to date, on thin-film ...

  12. Optimization of processing and modeling issues for thin film solar cell devices: Final report, February 3, 1997--September 1, 1998

    Birkmire, R. W.; Phillips, J. E.; Shafarman, W. N.; Hegedus, S. S.; McCandless, B. E.

    2000-02-28

    This final report describes results achieved under a 20-month NREL subcontract to develop and understand thin-film solar cell technology associated to CuInSe{sub 2} and related alloys, a-Si and its alloys, and CdTe. Modules based on all these thin films are promising candidates to meet DOE's long-range efficiency, reliability and manufacturing cost goals. The critical issues being addressed under this program are intended to provide the science and engineering basis for the development of viable commercial processes and to improve module performance. The generic research issues addressed are: (1) quantitative analysis of processing steps to provide information for efficient commercial-scale equipment design and operation; (2) device characterization relating the device performance to materials properties and process conditions; (3) development of alloy materials with different bandgaps to allow improved device structures for stability and compatibility with module design; (4) development and improved window/heterojunction layers and contacts to improve device performance and reliability; and (5) evaluation of cell stability with respect to device structure and module encapsulation.

  13. Thin-Film Solar Cells with InP Absorber Layers Directly Grown on Nonepitaxial Metal Substrates

    Zheng, Maxwell

    2015-08-25

    The design and performance of solar cells based on InP grown by the nonepitaxial thin-film vapor-liquid-solid (TF-VLS) growth technique is investigated. The cell structure consists of a Mo back contact, p-InP absorber layer, n-TiO2 electron selective contact, and indium tin oxide transparent top electrode. An ex situ p-doping process for TF-VLS grown InP is introduced. Properties of the cells such as optoelectronic uniformity and electrical behavior of grain boundaries are examined. The power conversion efficiency of first generation cells reaches 12.1% under simulated 1 sun illumination with open-circuit voltage (VOC) of 692 mV, short-circuit current (JSC) of 26.9 mA cm-2, and fill factor (FF) of 65%. The FF of the cell is limited by the series resistances in the device, including the top contact, which can be mitigated in the future through device optimization. The highest measured VOC under 1 sun is 692 mV, which approaches the optically implied VOC of ≈795 mV extracted from the luminescence yield of p-InP. The design and performance of solar cells based on indium phosphide (InP) grown by the nonepitaxial thin-film vapor-liquid-solid growth technique is investigated. The cell structure consists of a Mo back contact, p-InP absorber layer, n-TiO2 electron selective contact, and an indium tin oxide transparent top electrode. The highest measured open circuit voltage (VOC) under 1 sun is 692 mV, which approaches the optically implied VOC of ≈795 mV extracted from the luminescence yield of p-InP.

  14. Photoelectrode thin film of dye-sensitized solar cell fabricated by anodizing method and spin coating and electrochemical impedance properties of DSSC

    Chang, Ho, E-mail: f10381@ntut.edu.tw [Graduate Institute of Manufacturing Technology, National Taipei University of Technology, Taipei 10608, Taiwan (China); Chen, Chih-Hao [Department of Thoracic Surgery, Mackay Memorial Hospital, Taipei 10419, Taiwan (China); Graduate Institute of Mechanical and Electrical Engineering, National Taipei University of Technology, Taipei 10608, Taiwan (China); Kao, Mu-Jung [Department of Vehicle Engineering, National Taipei University of Technology, Taipei 10608, Taiwan (China); Chien, Shu-Hua [Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan (China); Chou, Cheng-Yi [Graduate Institute of Manufacturing Technology, National Taipei University of Technology, Taipei 10608, Taiwan (China)

    2013-06-15

    The paper studies the photoelectrode thin film of dye-sensitized solar cell (DSSC) fabricated by anodizing method, explores the structure and properties of the fabricated photoelectrode thin film, measures the photoelectric conversion efficiency of DSSC, and finds the electrochemical impedance properties of DSSCs assembled by photoelectrode thin films in different thicknesses. Besides, in order to increase the specific surface area of nanotubes, this paper deposits TiO{sub 2} nanoparticles (TNP) on the surface of titanium oxide nanotube (TNT). As shown in experimental results, the photoelectric conversion efficiency of the DSSC fabricated by the study rises to 6.5% from the original 5.43% without TnB treatment, with an increase of photoelectric conversion efficiency by 19.7%. In addition, when the photoelectrode thin film is fabricated with mixture of TNTs and TNP in an optimal proportion of 2:8 and the photoelectrode thin film thickness is 15.5 μm, the photoelectric conversion efficiency can reach 7.4%, with an increase of 36.7% from the original photoelectric conversion efficiency at 5.43%. Besides, as found in the results of electrochemical impedance analysis, the DSSC with photoelectrode thin film thickness at 15.5 μm has the lowest charge-conduction resistance (R{sub k}) value 9.276 Ω of recombined electron and conduction resistance (R{sub w}) value 3.25 Ω of electrons in TiO{sub 2}.

  15. Photoelectrode thin film of dye-sensitized solar cell fabricated by anodizing method and spin coating and electrochemical impedance properties of DSSC

    The paper studies the photoelectrode thin film of dye-sensitized solar cell (DSSC) fabricated by anodizing method, explores the structure and properties of the fabricated photoelectrode thin film, measures the photoelectric conversion efficiency of DSSC, and finds the electrochemical impedance properties of DSSCs assembled by photoelectrode thin films in different thicknesses. Besides, in order to increase the specific surface area of nanotubes, this paper deposits TiO2 nanoparticles (TNP) on the surface of titanium oxide nanotube (TNT). As shown in experimental results, the photoelectric conversion efficiency of the DSSC fabricated by the study rises to 6.5% from the original 5.43% without TnB treatment, with an increase of photoelectric conversion efficiency by 19.7%. In addition, when the photoelectrode thin film is fabricated with mixture of TNTs and TNP in an optimal proportion of 2:8 and the photoelectrode thin film thickness is 15.5 μm, the photoelectric conversion efficiency can reach 7.4%, with an increase of 36.7% from the original photoelectric conversion efficiency at 5.43%. Besides, as found in the results of electrochemical impedance analysis, the DSSC with photoelectrode thin film thickness at 15.5 μm has the lowest charge-conduction resistance (Rk) value 9.276 Ω of recombined electron and conduction resistance (Rw) value 3.25 Ω of electrons in TiO2.

  16. New diarylmethanofullerene derivatives and their properties for organic thin-film solar cells

    Daisuke Sukeguchi

    2009-02-01

    Full Text Available A number of diarylmethanofullerene derivatives were synthesized. The cyclopropane ring of the derivatives has two aryl groups substituted with electron-withdrawing and -donating groups, the latter with long alkyl chains to improve solubility in organic solvents, an important property in processing cells. First reduction potentials of most derivatives were less negative than that of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM, which is possibly ascribed to their electron-withdrawing nature. Organic thin-film photovoltaic cells fabricated with poly(3-hexylthiophene (P3HT as the electron-donor and diarylmethanofullerene derivatives as the electron-acceptor material were examined. The {(methoxycarbonylphenyl[bis(octyloxyphenyl]methano}fullerene showed power conversion efficiency as high as PCBM, but had higher solubility in a variety of organic solvents than PCBM. The Voc value was higher than that of PCBM, which is derived from the electron-donating (octyloxyphenyl group, possibly raising the LUMO level. Photovoltaic effects of the devices fabricated with the derivatives having some electron-withdrawing groups were also examined.

  17. Development of thin film space solar cells with multi-junction

    The present and future state of research and development in JAXA are introduced on the downsizing and weight reduction of solar panels. The circumstance of development, special feature and efficiency in the latest solar cells are explained. Further, its radiation resistance is shown by comparison with the three-junction solar cells used at present. (M.H.)

  18. Effect of fluorine plasma treatment with chemically reduced graphene oxide thin films as hole transport layer in organic solar cells

    The inorganic materials such as V2O5, MoO3 and WO3 were investigated to replace PEDOT:PSS as hole transport layer (HTL) in organic electronic devices such as organic solar cells (OSCs) and organic lighting emission diodes. However, these methods require vacuum techniques that are long time process and complex. Here, we report about plasma treatment with SF6 and CF4 using reactive ion etching on reduced graphene oxide (rGO) thin films that are obtained using an eco-friendly method with vitamin C. The plasma treated rGO thin films have dipoles since they consist of covalent bonds with fluorine on the surface of rGO. This means it is possible to increase the electrostatic potential energy than bare rGO. Increased potential energy on the surface of rGO films is worth applying organic electronic devices as HTL such as OSCs. Consequently, the power conversion efficiency of OSCs increased more than the rGO films without plasma treatment.

  19. Manipulating Crystallization of Organolead Mixed-Halide Thin Films in Antisolvent Baths for Wide-Bandgap Perovskite Solar Cells.

    Zhou, Yuanyuan; Yang, Mengjin; Game, Onkar S; Wu, Wenwen; Kwun, Joonsuh; Strauss, Martin A; Yan, Yanfa; Huang, Jinsong; Zhu, Kai; Padture, Nitin P

    2016-01-27

    Wide-bandgap perovskite solar cells (PSCs) based on organolead (I, Br)-mixed halide perovskites (e.g., MAPbI2Br and MAPbIBr2 perovskite with bandgaps of 1.77 and 2.05 eV, respectively) are considered as promising low-cost alternatives for application in tandem or multijunction photovoltaics (PVs). Here, we demonstrate that manipulating the crystallization behavior of (I, Br)-mixed halide perovskites in antisolvent bath is critical for the formation of smooth, dense thin films of these perovskites. Since the growth of perovskite grains from a precursor solution tends to be more rapid with increasing Br content, further enhancement in the nucleation rate becomes necessary for the effective decoupling of the nucleation and the crystal-growth stages in Br-rich perovskites. This is enabled by introducing simple stirring during antisolvent-bathing, which induces enhanced advection transport of the extracted precursor-solvent into the bath environment. Consequently, wide-bandgap planar PSCs fabricated using these high quality mixed-halide perovskite thin films, Br-rich MAPbIBr2, in particular, show enhanced PV performance. PMID:26726763

  20. Enhanced electrical properties at boundaries including twin boundaries of polycrystalline CdTe thin-film solar cells.

    Li, H; Liu, X X; Lin, Y S; Yang, B; Du, Z M

    2015-05-01

    The effect of grain boundaries (GBs), in particular twin boundaries (TBs), on CdTe polycrystalline thin films is studied by conductive atomic force microscopy (C-AFM), electron-beam-induced current (EBIC), scanning Kelvin probe microscopy (SKPM), electron backscatter diffraction (EBSD), and scanning transmission electron microscopy (STEM). Four types of CdTe grains with various densities of {111} ?3 twin boundaries (TBs) are found in Cl-treated CdTe polycrystalline thin films: (1) grains having multiple {111} ?3 TBs with a low angle to the film surface; (2) grains having multiple {111} ?3 TBs parallel to the film surfaces; (3) small grains on a scale of not more than 500 nm, composed of Cd, Cl, Te, and O; and (4) CdTe grains with not more than two {111} ?3 TBs. Grain boundaries (including TBs) exhibit enhanced current transport phenomena. However, the {111} ?3 TB is much more beneficial to micro-current transport. The enhanced current transport can be explained by the lower electron potential at GBs (including TBs) than the grain interiors (GIs). Our results open new opportunities for enhancing solar cell performances by controlling the grain boundaries, and in particular TBs. PMID:25857742

  1. Effect of fluorine plasma treatment with chemically reduced graphene oxide thin films as hole transport layer in organic solar cells

    Yu, Youn-Yeol; Kang, Byung Hyun; Lee, Yang Doo; Lee, Sang Bin; Ju, Byeong-Kwon, E-mail: bkju@korea.ac.kr

    2013-12-15

    The inorganic materials such as V{sub 2}O{sub 5}, MoO{sub 3} and WO{sub 3} were investigated to replace PEDOT:PSS as hole transport layer (HTL) in organic electronic devices such as organic solar cells (OSCs) and organic lighting emission diodes. However, these methods require vacuum techniques that are long time process and complex. Here, we report about plasma treatment with SF{sub 6} and CF{sub 4} using reactive ion etching on reduced graphene oxide (rGO) thin films that are obtained using an eco-friendly method with vitamin C. The plasma treated rGO thin films have dipoles since they consist of covalent bonds with fluorine on the surface of rGO. This means it is possible to increase the electrostatic potential energy than bare rGO. Increased potential energy on the surface of rGO films is worth applying organic electronic devices as HTL such as OSCs. Consequently, the power conversion efficiency of OSCs increased more than the rGO films without plasma treatment.

  2. Effect of fluorine plasma treatment with chemically reduced graphene oxide thin films as hole transport layer in organic solar cells

    Yu, Youn-Yeol; Kang, Byung Hyun; Lee, Yang Doo; Lee, Sang Bin; Ju, Byeong-Kwon

    2013-12-01

    The inorganic materials such as V2O5, MoO3 and WO3 were investigated to replace PEDOT:PSS as hole transport layer (HTL) in organic electronic devices such as organic solar cells (OSCs) and organic lighting emission diodes. However, these methods require vacuum techniques that are long time process and complex. Here, we report about plasma treatment with SF6 and CF4 using reactive ion etching on reduced graphene oxide (rGO) thin films that are obtained using an eco-friendly method with vitamin C. The plasma treated rGO thin films have dipoles since they consist of covalent bonds with fluorine on the surface of rGO. This means it is possible to increase the electrostatic potential energy than bare rGO. Increased potential energy on the surface of rGO films is worth applying organic electronic devices as HTL such as OSCs. Consequently, the power conversion efficiency of OSCs increased more than the rGO films without plasma treatment.

  3. Improving Si solar cell performance using Mn:ZnSe quantum dot-doped PLMA thin film

    Cheng, Dan-Chen; Hao, Hong-Chen; Zhang, Miao; Shi, Wei; Lu, Ming

    2013-06-01

    Poly(lauryl methacrylate) (PLMA) thin film doped with Mn:ZnSe quantum dots (QDs) was spin-deposited on the front surface of Si solar cell for enhancing the solar cell efficiency via photoluminescence (PL) conversion. Significant solar cell efficiency enhancements (approximately 5% to 10%) under all-solar-spectrum (AM0) condition were observed after QD-doped PLMA coatings. Furthermore, the real contribution of the PL conversion was precisely assessed by investigating the photovoltaic responses of the QD-doped PLMA to monochromatic and AM0 light sources as functions of QD concentration, combined with reflectance and external quantum efficiency measurements. At a QD concentration of 1.6 mg/ml for example, among the efficiency enhancement of 5.96%, about 1.04% was due to the PL conversion, and the rest came from antireflection. Our work indicates that for the practical use of PL conversion in solar cell performance improvement, cautions are to be taken, as the achieved efficiency enhancement might not be wholly due to the PL conversion.

  4. Process for fabricating polycrystalline semiconductor thin-film solar cells, and cells produced thereby

    Wu, Xuanzhi; Sheldon, Peter

    2000-01-01

    A novel, simplified method for fabricating a thin-film semiconductor heterojunction photovoltaic device includes initial steps of depositing a layer of cadmium stannate and a layer of zinc stannate on a transparent substrate, both by radio frequency sputtering at ambient temperature, followed by the depositing of dissimilar layers of semiconductors such as cadmium sulfide and cadmium telluride, and heat treatment to convert the cadmium stannate to a substantially single-phase material of a spinel crystal structure. Preferably, the cadmium sulfide layer is also deposited by radio frequency sputtering at ambient temperature, and the cadmium telluride layer is deposited by close space sublimation at an elevated temperature effective to convert the amorphous cadmium stannate to the polycrystalline cadmium stannate with single-phase spinel structure.

  5. Growth, etching, and stability of sputtered ZnO:Al for thin-film silicon solar cells

    Owen, Jorj Ian

    2011-07-01

    Aluminum-doped zinc oxide (ZnO:Al) can fulfill many requirements in thin-film solar cells, acting as (1) a transparent contact through which the incident light is transmitted, (2) part of the back reflector, and (3) a source of light scattering. Magnetron sputtered ZnO:Al thin-films are highly transparent, conductive, and are typically texturized by post-deposition etching in a dilute hydrochloric acid (HCl) solution to achieve light scattering. The ZnO:Al thin-film electronic and optical properties, as well as the surface texture after etching, depend on the deposition conditions and the post-deposition treatments. Despite having been used in thin-film solar cells for more than a decade, many aspects regarding the growth, effects of heat treatments, environmental stability, and etching of sputtered ZnO:Al are not fully understood. This work endeavors to further the understanding of ZnO:Al for the purpose improving silicon thin-film solar cell efficiency and reducing ZnO:Al production costs. With regard to the growth of ZnO:Al, the influence of various deposition conditions on the resultant electrical and structural properties and their evolution with film thickness were studied. The surface electrical properties extracted from a multilayer model show that while carrier concentration of the surface layer saturates already at film thickness of 100 nm, the surface mobility continues to increases with film thickness, and it is concluded that electronic transport across grain boundaries limits mobility in ZnO:Al thin films. ZnO:Al deposited onto a previously etched ZnO:Al surface grows epitaxially, preserving both the original orientation and grain structure. Further, it is determined that a typical ZnO:Al used in thin-film silicon solar cells grows Zn-terminated on glass substrates. Concerning the affects of heat treatments and stability, it is demonstrated that a layer of amorphous silicon can protect ZnO:Al from degradation during annealing, and the mobility of ZnO:Al films can be increased up to 76 cm{sup 2}/Vs by annealing at high temperatures. Further, it is observed that this annealing process does not affect the morphology of the film and increases the total transmission in the solar cell relevant portion of the spectrum. Accelerated aging in a damp-heat is shown to affect the mobility primarily, and is thus likely related to poor transport across grain boundaries. Using deuterium as an isotopic marker, it is observed that the deuterium uptake was fairly linear with time and penetrated the whole film within 24 hours. Additionally, the deuterium is quickly replaced by hydrogen upon damp-heat treatment in water. It is concluded that the electrical degradation is related to the penetration of water via grain boundaries, and that the bulk of the reactions causing this degradation are fairly weak, such as the formation of zinc hydroxide. Additionally, the annealed high-mobility ZnO:Al films prove to be very stable in the damp-heat environment, exhibiting electron mobilities above 70 cm{sup 2}/Vs after 1000 hours of exposure. The initial points of attack during HCl etching of ZnO:Al, and the long-term etch evolution are shown to be related to certain grain boundaries built into the film during growth. The density of craters from an HCl etch is controllable by altering the temperature and concentration of the etching solution. It is further demonstrated that most acids exhibit etching behavior similar to that of HCl. Hydrofluoric acid (HF), however, exhibits unique etching characteristics with higher crater densities and sharper features. The crater density and shape are also shown to be controllable by etching in various concentrations of HF and in various mixtures of HF and HCl. Additional etching experiments are made to develop a polycrystalline ZnO:Al etching model. It is shown that basic and acidic solutions attack the same points on a polycrystalline ZnO:Al sample. The dependence of crater density on the acid concentration, temperature, and type holds true for single crystal ZnO. Planar and cross-sectional transmission electron microscopy (TEM) measurements confirmed grain boundaries as the most prevalent catalysts for etching. A three-postulate etching model is proposed, the basics of which are: (1) every grain boundary has certain potential to etch, and this potential depends on the compactness of the grain boundary;(2) the etchant solution and conditions define an etching threshold, and grain boundaries with etching potentials above the threshold are actively etched; and (3) the vertical and horizontal etch rates are defined by the solution, and vertically limited etching leads to the characteristic crater opening angles while a horizontal limited etch yields sharper structures. Examples on how the better understanding of ZnO:Al can lead to more efficient solar cells and more reliable ZnO:Al film preparation are also given.

  6. Polycrystalline-thin-film thermophotovoltaic cells

    Dhere, Neelkanth G.

    1996-02-01

    Thermophotovoltaic (TPV) cells convert thermal energy to electricity. Modularity, portability, silent operation, absence of moving parts, reduced air pollution, rapid start-up, high power densities, potentially high conversion efficiencies, choice of a wide range of heat sources employing fossil fuels, biomass, and even solar radiation are key advantages of TPV cells in comparison with fuel cells, thermionic and thermoelectric convertors, and heat engines. The potential applications of TPV systems include: remote electricity supplies, transportation, co-generation, electric-grid independent appliances, and space, aerospace, and military power applications. The range of bandgaps for achieving high conversion efficiencies using low temperature (1000-2000 K) black-body or selective radiators is in the 0.5-0.75 eV range. Present high efficiency convertors are based on single crystalline materials such as In1-xGaxAs, GaSb, and Ga1-xInxSb. Several polycrystalline thin films such as Hg1-xCdxTe, Sn1-xCd2xTe2, and Pb1-xCdxTe, etc., have great potential for economic large-scale applications. A small fraction of the high concentration of charge carriers generated at high fluences effectively saturates the large density of defects in polycrystalline thin films. Photovoltaic conversion efficiencies of polycrystalline thin films and PV solar cells are comparable to single crystalline Si solar cells, e.g., 17.1% for CuIn1-xGaxSe2 and 15.8% for CdTe. The best recombination-state density Nt is in the range of 10-15-10-16 cm-3 acceptable for TPV applications. Higher efficiencies may be achieved because of the higher fluences, possibility of bandgap tailoring, and use of selective emitters such as rare earth oxides (erbia, holmia, yttria) and rare earth-yttrium aluminium garnets. As compared to higher bandgap semiconductors such as CdTe, it is easier to dope the lower bandgap semiconductors. TPV cell development can benefit from the more mature PV solar cell and opto-electronic (infrared detectors, lasers, and optical communications) technologies. Low bandgaps and larger fluences employed in TPV cells result in very high current densities which make it difficult to collect the current effectively. Techniques for laser and mechanical scribing, integral interconnection, and multi-junction tandem structures which have been fairly well developed for thin-film PV solar cells could be further refined for enhancing the voltages from TPV modules. Thin-film TPV cells may be deposited on metals or back-surface reflectors. Spectral control elements such as indium-tin oxide or tin oxide may be deposited directly on the TPV convertor. It would be possible to reduce the cost of TPV technologies based on single-crystal materials being developed at present to the range of US 2-5 per watt so as to be competitive in small to medium size commercial applications. However, a further cost reduction to the range of US 35- 1 per watt to reach the more competitive large-scale residential, consumer, and hybrid-electric car markets would be possible only with the polycrystalline-thin film TPV cells.

  7. Improving low pressure chemical vapor deposited zinc oxide contacts for thin film silicon solar cells by using rough glass substrates

    Compared to zinc oxide grown (ZnO) on flat glass, rough etched glass substrates decrease the sheet resistance (Rsq) of zinc oxide layers grown on it. We explain this Rsq reduction from a higher thickness and an improved electron mobility for ZnO layers deposited on rough etched glass substrates. When using this etched glass substrate, we also obtain a large variety of surface texture by changing the thickness of the ZnO layer grown on it. This new combination of etched glass and ZnO layer shows improved light trapping potential compared to ZnO films grown on flat glass. With this new approach, Micromorph thin film silicon tandem solar cells with high total current densities (sum of the top and bottom cell current density) of up to 26.8 mA cm?2 were fabricated.

  8. Preparation of aluminium doped zinc oxide thin films for the transparent conducting electrode application for hydrogenated amorphous solar cells

    Transparent conducting thin films of undoped and aluminium doped zinc oxide have been deposited by spray pyrolysis technique. The substrate temperature, solution spray rate and aluminium concentration have been identified as the important deposition parameters and their effects on the electrical optical and microstructural properties have been studied. Films having Al/Zn ratio of 1.75 at. %, deposited under optimized condition exhibit good transparent conducting properties (T/sub v/ is approx. equal to 83 % and R/sub s/ is approx. equal to 12-20 omega/square). zinc oxide based hydrogenated amorphous silicon solar cells (Glass/ZnO: Al/Pin/Al) have been fabricated by PECVD (Plasma enhanced chemical vapour deposition) technique. The measurement of I-V characteristic and spectral response of these cells has been investigated. (author)

  9. Growth of Cu2ZnSnS4 absorber layer on flexible metallic substrates for thin film solar cell applications

    In this work, Cu2ZnSnS4 (CZTS) absorber layers were fabricated using a two-stage process. Sequentially deposited Cu–Zn–Sn thin film layers on metallic foils were annealed in an Ar + S2(g) atmosphere. We aimed to investigate the role of flexible titanium and molybdenum foil substrates in the growth mechanism of CZTS thin films. The Raman spectra and X-ray photoelectron spectroscopy analyses of the sulfurized thin films revealed that, except for the presence of Sn-based secondary phases, nearly pure CZTS thin films were obtained. Additionally, the intense and sharp X-ray diffraction peak from the (112) plane provided evidence of good crystallinity. Electron dispersive spectroscopy analysis indicated sufficient sulfur content but poor Zn atomic weight percentage in the films. Absorption and band-gap energy analyses were carried out to confirm the suitability of CZTS thin films as the absorber layer in solar cell applications. Hall effect measurements showed the p-type semiconductor behavior of the CZTS samples. Moreover, the back contact behavior of these metallic flexible substrates was investigated and compared. We detected formation of cracks in the CZTS layer on the molybdenum foils, which indicates the incompatibility of molybdenum's thermal expansion coefficient with the CZTS structure. We demonstrated the application of the magnetron sputtering technique for the fabrication of CZTS thin films on titanium foils having lightweight, flexible properties and suitable for roll-to-roll manufacturing for high throughput fabrication. Titanium foils are also cost competitive compared to molybdenum foils. - Highlights: • Growth of CZTS layer for thin film solar cell applications • CZTS growth on metallic flexible foil substrates by magnetron sputtering technique • Lightweight and flexible substrate is feasible for roll-to-roll manufacturing. • Crack formation on Mo foil substrate due to mismatch of CTE between Mo and CZTS • Ti foil is preferred due to its low cost and with nearly equal CTE to that of CZTS

  10. Wide-spectrum Mg and Ga co-doped ZnO TCO thin films for solar cells grown via magnetron sputtering with H2 introduction

    Chen, Xin-liang; Liu, Jie-ming; Ni, Jian; Zhao, Ying; Zhang, Xiao-dan

    2015-02-01

    Wide-spectrum Mg and Ga co-doped ZnO transparent conductive oxide (TCO) thin films are deposited via magnetron sputtering at various H2 flow rates on glass substrates. The structural, electrical, and optical properties of MGZO thin films are investigated with different H2 flow rates. The experiment results show that the MGZO thin films are polycrystalline with a hexagonal wurtzite structure exhibiting a preferred (0 0 2) crystal plane orientation. The carrier concentration remarkably increases from 5.15 1019 cm-3 to 2.12 1020 cm-3 with increasing the H2 flow rate from 0 sccm to 4.0 sccm and then decreases when further increasing the H2 flow rate. The glass/MGZO thin film deposited at the H2 flow rate of 4.0 sccm exhibits the lowest resistivity of 1.96 10-3 ? cm (film thickness d ? 548 nm) and an average transmittance (Ta) of 80.5% in the wavelength range from 340 nm to 1100 nm. Optical measurements indicate that the optical band gap (Eg) of MGZO thin films varies from 3.45 eV to 3.78 eV with adjusting H2 flow rate from 0 sccm to 12.0 sccm. The obtained MGZO thin films with an appropriate thickness are preliminarily applied in p-i-n type hydrogenated amorphous silicon (a-Si:H) thin film solar cells. The a-Si:H solar cell with MGZO layer presents higher quantum efficiency in the short wavelength region than that with GZO layer, resulting from widened optical band gap.

  11. Highly transparent front electrodes with metal fingers for p-i-n thin-film silicon solar cells

    Moulin Etienne

    2015-01-01

    Full Text Available The optical and electrical properties of transparent conductive oxides (TCOs, traditionally used in thin-film silicon (TF-Si solar cells as front-electrode materials, are interlinked, such that an increase in TCO transparency is generally achieved at the cost of reduced lateral conductance. Combining a highly transparent TCO front electrode of moderate conductance with metal fingers to support charge collection is a well-established technique in wafer-based technologies or for TF-Si solar cells in the substrate (n-i-p configuration. Here, we extend this concept to TF-Si solar cells in the superstrate (p-i-n configuration. The metal fingers are used in conjunction with a millimeter-scale textured foil, attached to the glass superstrate, which provides an antireflective and retroreflective effect; the latter effect mitigates the shadowing losses induced by the metal fingers. As a result, a substantial increase in power conversion efficiency, from 8.7% to 9.1%, is achieved for 1-?m-thick microcrystalline silicon solar cells deposited on a highly transparent thermally treated aluminum-doped zinc oxide layer combined with silver fingers, compared to cells deposited on a state-of-the-art zinc oxide layer.

  12. Highly transparent front electrodes with metal fingers for p-i-n thin-film silicon solar cells

    Moulin, Etienne; Mller, Thomas Christian Mathias; Warzechac, Marek; Hoffmann, Andre; Paetzold, Ulrich Wilhelm; Aeberhard, Urs

    2015-03-01

    The optical and electrical properties of transparent conductive oxides (TCOs), traditionally used in thin-film silicon (TF-Si) solar cells as front-electrode materials, are interlinked, such that an increase in TCO transparency is generally achieved at the cost of reduced lateral conductance. Combining a highly transparent TCO front electrode of moderate conductance with metal fingers to support charge collection is a well-established technique in wafer-based technologies or for TF-Si solar cells in the substrate (n-i-p) configuration. Here, we extend this concept to TF-Si solar cells in the superstrate (p-i-n) configuration. The metal fingers are used in conjunction with a millimeter-scale textured foil, attached to the glass superstrate, which provides an antireflective and retroreflective effect; the latter effect mitigates the shadowing losses induced by the metal fingers. As a result, a substantial increase in power conversion efficiency, from 8.7% to 9.1%, is achieved for 1-?m-thick microcrystalline silicon solar cells deposited on a highly transparent thermally treated aluminum-doped zinc oxide layer combined with silver fingers, compared to cells deposited on a state-of-the-art zinc oxide layer.

  13. Textured surface boron-doped ZnO transparent conductive oxides on polyethylene terephthalate substrates for Si-based thin film solar cells

    Textured surface boron-doped zinc oxide (ZnO:B) thin films were directly grown via low pressure metal organic chemical vapor deposition (LP-MOCVD) on polyethylene terephthalate (PET) flexible substrates at low temperatures and high-efficiency flexible polymer silicon (Si) based thin film solar cells were obtained. High purity diethylzinc and water vapors were used as source materials, and diborane was used as an n-type dopant gas. P-i-n silicon layers were fabricated at ∼ 398 K by plasma enhanced chemical vapor deposition. These textured surface ZnO:B thin films on PET substrates (PET/ZnO:B) exhibit rough pyramid-like morphology with high transparencies (T ∼ 80%) and excellent electrical properties (Rs ∼ 10 Ω at d ∼ 1500 nm). Finally, the PET/ZnO:B thin films were applied in flexible p-i-n type silicon thin film solar cells (device structure: PET/ZnO:B/p-i-n a-Si:H/Al) with a high conversion efficiency of 6.32% (short-circuit current density JSC = 10.62 mA/cm2, open-circuit voltage VOC = 0.93 V and fill factor = 64%).

  14. Broadband photocurrent enhancement and light-trapping in thin film Si solar cells with periodic Al nanoparticle arrays on the front

    Uhrenfeldt, C.; Villesen, T. F.; Tetu, A.; Johansen, B.; Larsen, A. Nylandsted

    2015-01-01

    front of a thin film Si test solar cell. It is demonstrated that the resonances from the Al nanoparticle array cause a broadband photocurrent enhancement ranging from the ultraviolet to the infrared with respect to a reference cell. From the experimental results as well as from numerical simulations it......Plasmonic resonances in metal nanoparticles are considered candidates for improved thin film Si photovoltaics. In periodic arrays the influence of collective modes can enhance the resonant properties of such arrays. We have investigated the use of periodic arrays of Al nanoparticles placed on the...

  15. Performance enhancement of thin film silicon solar cells based on distributed Bragg reflector & diffraction grating

    R. S. Dubey

    2014-12-01

    Full Text Available The influence of various designing parameters were investigated and explored for high performance solar cells. Single layer grating based solar cell of 50 ?m thickness gives maximum efficiency up to 24 % whereas same efficiency is achieved with the use of three bilayers grating based solar cell of 30 ?m thickness. Remarkably, bilayer grating based solar cell design not only gives broadband absorption but also enhancement in efficiency with reduced cell thickness requirement. This absorption enhancement is attributed to the high reflection and diffraction from DBR and grating respectively. The obtained short-circuit current were 29.6, 32.9, 34.6 and 36.05 mA/cm2 of 5, 10, 20 and 30 ?m cell thicknesses respectively. These presented designing efforts would be helpful to design and realize new generation of solar cells.

  16. Performance enhancement of thin film silicon solar cells based on distributed Bragg reflector and diffraction grating

    The influence of various designing parameters were investigated and explored for high performance solar cells. Single layer grating based solar cell of 50 μm thickness gives maximum efficiency up to 24 % whereas same efficiency is achieved with the use of three bilayers grating based solar cell of 30 μm thickness. Remarkably, bilayer grating based solar cell design not only gives broadband absorption but also enhancement in efficiency with reduced cell thickness requirement. This absorption enhancement is attributed to the high reflection and diffraction from DBR and grating respectively. The obtained short-circuit current were 29.6, 32.9, 34.6 and 36.05 mA/cm2 of 5, 10, 20 and 30 μm cell thicknesses respectively. These presented designing efforts would be helpful to design and realize new generation of solar cells

  17. Electrical properties and surface morphology of electron beam evaporated p-type silicon thin films on polyethylene terephthalate for solar cells applications

    Ang, P. C.; Ibrahim, K.; Pakhuruddin, M. Z. [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, Minden 11800 Penang (Malaysia)

    2015-04-24

    One way to realize low-cost thin film silicon (Si) solar cells fabrication is by depositing the films with high-deposition rate and manufacturing-compatible electron beam (e-beam) evaporation onto inexpensive foreign substrates such as glass or plastic. Most of the ongoing research is reported on e-beam evaporation of Si films on glass substrates to make polycrystalline solar cells but works combining both e-beam evaporation and plastic substrates are still scarce in the literature. This paper studies electrical properties and surface morphology of 1 µm electron beam evaporated Al-doped p-type silicon thin films on textured polyethylene terephthalate (PET) substrate for application as an absorber layer in solar cells. In this work, Si thin films with different doping concentrations (including an undoped reference) are prepared by e-beam evaporation. Energy dispersion X-ray (EDX) showed that the Si films are uniformly doped by Al dopant atoms. With increased Al/Si ratio, doping concentration increased while both resistivity and carrier mobility of the films showed opposite relationships. Root mean square (RMS) surface roughness increased. Overall, the Al-doped Si film with Al/Si ratio of 2% (doping concentration = 1.57×10{sup 16} atoms/cm{sup 3}) has been found to provide the optimum properties of a p-type absorber layer for fabrication of thin film Si solar cells on PET substrate.

  18. Transmission Electron Microscopy of the Textured Silver Back Reflector of a Thin Film Silicon Solar Cell: From Crystallography to Optical Absorption

    Duchamp, Martial; Söderström, K.; Jeangros, Q.; Boothroyd, Chris; Kovacs, A.; Kasama, Takeshi; Haug, F.-J; Ballif, C.; Dunin-Borkowski, Rafal E.; Ossenbrink, H.; Jager-Waldau, A.; Helm, P.

    The study of light trapping in amorphous, microcrystalline and micromorph thin-film Si solar cells is an important and active field of investigation. It has been demonstrated that the use of a rough Ag back-reflector lead to an increase of short circuit current but also to losses through the crea...

  19. Electrical properties and surface morphology of electron beam evaporated p-type silicon thin films on polyethylene terephthalate for solar cells applications

    One way to realize low-cost thin film silicon (Si) solar cells fabrication is by depositing the films with high-deposition rate and manufacturing-compatible electron beam (e-beam) evaporation onto inexpensive foreign substrates such as glass or plastic. Most of the ongoing research is reported on e-beam evaporation of Si films on glass substrates to make polycrystalline solar cells but works combining both e-beam evaporation and plastic substrates are still scarce in the literature. This paper studies electrical properties and surface morphology of 1 µm electron beam evaporated Al-doped p-type silicon thin films on textured polyethylene terephthalate (PET) substrate for application as an absorber layer in solar cells. In this work, Si thin films with different doping concentrations (including an undoped reference) are prepared by e-beam evaporation. Energy dispersion X-ray (EDX) showed that the Si films are uniformly doped by Al dopant atoms. With increased Al/Si ratio, doping concentration increased while both resistivity and carrier mobility of the films showed opposite relationships. Root mean square (RMS) surface roughness increased. Overall, the Al-doped Si film with Al/Si ratio of 2% (doping concentration = 1.57×1016 atoms/cm3) has been found to provide the optimum properties of a p-type absorber layer for fabrication of thin film Si solar cells on PET substrate

  20. Reflectance improvement by thermal annealing of sputtered Ag/ZnO back reflectors in a-Si:H thin film silicon solar cells

    Haug, Franz-Josef; Söderström, Karin; Pahud, Céline; Biron, Rémi; Escarré, Jordi; Duchamp, Martial; Dunin-Borkowski, Rafal E.; Ballif, Christophe

    2011-01-01

    Silver can be used as the back contact and reflector in thin film silicon solar cells. When deposited on textured substrates, silver films often exhibit reduced reflectance due to absorption losses by the excitation of surface plasmon resonances. We show that thermal annealing of the silver back...

  1. Electrical properties and surface morphology of electron beam evaporated p-type silicon thin films on polyethylene terephthalate for solar cells applications

    Ang, P. C.; Ibrahim, K.; Pakhuruddin, M. Z.

    2015-04-01

    One way to realize low-cost thin film silicon (Si) solar cells fabrication is by depositing the films with high-deposition rate and manufacturing-compatible electron beam (e-beam) evaporation onto inexpensive foreign substrates such as glass or plastic. Most of the ongoing research is reported on e-beam evaporation of Si films on glass substrates to make polycrystalline solar cells but works combining both e-beam evaporation and plastic substrates are still scarce in the literature. This paper studies electrical properties and surface morphology of 1 m electron beam evaporated Al-doped p-type silicon thin films on textured polyethylene terephthalate (PET) substrate for application as an absorber layer in solar cells. In this work, Si thin films with different doping concentrations (including an undoped reference) are prepared by e-beam evaporation. Energy dispersion X-ray (EDX) showed that the Si films are uniformly doped by Al dopant atoms. With increased Al/Si ratio, doping concentration increased while both resistivity and carrier mobility of the films showed opposite relationships. Root mean square (RMS) surface roughness increased. Overall, the Al-doped Si film with Al/Si ratio of 2% (doping concentration = 1.571016 atoms/cm3) has been found to provide the optimum properties of a p-type absorber layer for fabrication of thin film Si solar cells on PET substrate.

  2. Evaluation of electrical shunt resistance in laser scribed thin-films for CIGS solar cells on flexible substrates

    Markauskas, E.; Ge?ys, P.; Ra?iukaitis, G.

    2015-03-01

    Formation of serial interconnects in thin-film solar cells is an important step for upscaling production yield over large areas. Laser scribing is a promising tool for monolithic interconnect formation in CIGS solar cell module. However, evaluation of alterations in electrical properties of the cells during the laser scribing is not a trivial task, especially for cells with flexible substrates when production is based on roll-to-roll processes. We applied the technique of nested circular scribes proposed by K. Zimmer et. al. for the in-line quality evaluation of the P3 scribing processes in CIGS solar cells on polyimide. Scribing experiments were performed using picosecond laser working at 532 nm wavelength. Parallel resistance values of the cells during the formation of P3 scribes were extracted by analyzing I-V characteristics of the measured photovoltaic devices. Integration of laser scribing experiments with the on-line electrical characterization facilitated optimization of the laser processes and increased the measurement accuracy of shunt formation during the laser scribing.

  3. On the physics of microcrystalline silicon thin film solar cells. From the material to devices with high conversion efficiences

    Vetterl, C.

    2001-08-01

    VHF-PECVD was used to prepare doped and undoped microcrystalline silicon for applications in thin-film solar cells. In addition, device preparation processes on glass substrates, covered with texture-etched zinc-oxide films, were developed. High conversion efficiencies of up to 8.7% and 10% for single junction solar cells and stacked solar cells were achieved, respectively. The deposition conditions of the intrinsic absorber layer were varied over a wide range and material properties such as crystalline volume content, conductivity and optical absorption as well as corresponding solar cell properties were investigated. It was found that the structural composition of the material is closely related to transport and recombination properties, resulting in optimum device performance under unexpected conditions close to the transition to amorphous growth. In particular, the dark conductivity of the material decreases upon approaching this transition starting from the highly crystalline range, e.g. by changing the dilution ratio of silane in hydrogen, while the efficiency of corresponding solar cells improves due to increasing open-circuit voltages. Simultaneously, the drawback of recombination losses observed for highly crystalline conditions, which can be attributed to a high defect density, is much improved. The upper limit of the efficiency improvement is reached at the set-in of amorphous growth. This transition occurs very abruptly in the solar cells due to local epitaxy on the doped contact layers. Beyond this point the beneficial increase of open-circuit voltage is overcompensated by a significant reduction of charge carrier generation and extraction efficiency. It is concluded that growth conditions close to the transition to amorphous growth, which in the solar cell still result in structurally homogeneous and highly crystalline material, are most suitable with respect to the device performance. (orig.)

  4. Photoluminescence of epitactical and polycrystalline CuInS2 layers for thin-film solar cells

    The present thesis deals with one- and polycrystalline CuInS2 absorber layers for thin-film solar cells and especially with their optical and structural characterization. By means of detailed temperature- and power-dependent photoluminescence measurements in epitactical and polycrystalline absorber layers different radiative transitions could be analyzed and identified. The spectra were dominated by broad luminescence bands of deep perturbing levels. The implantation of hydrogen at low energies led to a passivation of these perturbing levels. On the base of the optical studies on epitactical and polycrystalline absorber layers a new improved defect model for CuInS2 could be developed. The model contains two donor and two acceptor levels with following ionization energies: D-1=46 meV, D-2=87 meV, A-1=70 meV, and A-2=119 meV

  5. Manipulation of MWCNT Concentration in MWCNT/TiO2 Nanocomposite Thin Films for Dye-Sensitized Solar Cell

    Huda Abdullah; Mohd Zikri Razali; Sahbudin Shaari; Mohd Raihan Taha

    2014-01-01

    Dye-sensitized solar cell (DSSC) using multiwalled carbon nanotube/titanium dioxide (MWCNT/TiO2) was successfully synthesized using sol-gel method. In this method, it has been performed under various acid treatments MWCNT concentration level at (a) 0.00 g, (b) 0.01 g, (c) 0.02 g, and (d) 0.03 g. Atomic force microscopy (AFM) was used to study surface roughness of the MWCNT/TiO2 thin films. The average roughness results for 0.00 g, 0.01 g, 0.02 g, and 0.03 g were 10.995, 18.308, 24.322, and 25...

  6. Fabrication of dye sensitized solar cell using Cr doped Cu-Zn-Se type chalcopyrite thin film

    Joseph, D. Paul; Venkateswaran, C. [Materials Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai-600 025 (India); Ganesan, S.; Suthanthiraraj, S. Austin; Maruthamuthu, P. [Department of Energy, University of Madras, Guindy Campus, Chennai 600 025 (India); Kovendhan, M. [Department of Physics, Presidency College, Chennai 600 005 (India)

    2011-09-15

    Chalcopyrites are a versatile class of semiconductors known for their potential in photovoltaic applications. Considering the well established CuInSe{sub 2} as a prototype system, a new compound of the chalcopyrite type, Cu{sub 1-x}Zn{sub 1-y}Se{sub 2-{delta}}, by replacing In with Zn, has been prepared (both undoped and 2% Cr doped) by the metallurgical method. Thin films have been deposited by the thermal evaporation technique using the stabilized polycrystalline compounds as charge. Structural, compositional, morphological, and optical properties of the films are analyzed and reported. Use of these films as electrodes in dye sensitized solar cell (DSSC) is demonstrated. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Surface Modification of Polycrystalline Cu(In,Ga)Se2 Thin-Film Solar Cell Absorber Surfaces for PEEM Measurements

    Wilks, R. G.; Contreras, M. A.; Lehmann, S.; Herrero-Albillos, J.; Bismaths, L. T.; Kronast, F.; Noufi, R.; Bar, M.

    2011-01-01

    We present a thorough examination of the {micro}m-scale topography of Cu(In, Ga)Se{sub 2} ('CIGSe') thin-film solar cell absorbers using different microscopy techniques. We specifically focus on the efficacy of preparing smooth sample surfaces - by etching in aqueous bromine solution - for a spatially resolved study of their chemical and electronic structures using photoelectron emission microscopy (PEEM). The etching procedure is shown to reduce the CIGSe surface roughness from ca. 40 to 25 nm after 40s etching, resulting in an increase in the quality of the obtained PEEM images. Furthermore we find that the average observed grain size at the etched surfaces appears larger than at the unetched surfaces. Using a liftoff procedure, it is additionally shown that the backside of the absorber is flat but finely patterned, likely due to being grown on the finely-structured Mo back contact.

  8. Conducting glasses recovered from thin film transistor liquid crystal display wastes for dye-sensitized solar cell cathodes.

    Chen, C-C; Chang, F-C; Peng, C Y; Wang, H Paul

    2015-01-01

    Transparent conductive glasses such as thin film transistor (TFT) array and colour filter glasses were recovered from the TFT-liquid crystal display panel wastes by dismantling and sonic cleaning. Noble metals (i.e. platinum (Pt)) and indium tin oxide (ITO) are generally used in the cathode of a dye-sensitized solar cell (DSSC). To reduce the DSSC cost, Pt was replaced with nano nickel-encapsulated carbon-shell (Ni@C) nanoparticles, which were prepared by carbonization of Ni²⁺-β-cyclodextrin at 673 K for 2 h. The recovered conductive glasses were used in the DSSC electrodes in the substitution of relatively expensive ITO. Interestingly, the efficiency of the DSSC having the Ni@C-coated cathode is as high as 2.54%. Moreover, the cost of the DSSC using the recovered materials can be reduced by at least 24%. PMID:25399759

  9. Nano-scale texturing of borosilicate glasses using CF4-based plasma discharge for application in thin film solar cells.

    Kim, Hyung Soo; Lim, Jung Wook; Yun, Sun Jin; Lee, Heon; Lee, Hee Chul

    2012-04-01

    Random plasma treatment techniques were used as a texturing method to reduce the surface reflection of glass substrates in thin film solar cells. Various gas mixtures were used for the plasma discharge in an effort to examine the texturing mechanism. Using a plasma treatment comprising CF4/O2 and CF4/Ar with a gas flow ratio of 1 to 2, the surface reflectance could be decreased to 6.83% and 6.82%, respectively. The surface treatment was very effective with the use of a low RF power of 50 W and an optimal time of 5 min. It is considered that the optical characteristics of the glass substrate are highly correlated to its surface morphology which can be produced not only through nano-scale chemical reactions with radicals but also through ion flux bombardment. PMID:22849147

  10. XPS characterization of sensitized n-TiO2 thin films for dye-sensitized solar cell applications

    TiO2 thin films, employed in dye-sensitized solar cells, were prepared by the sol-gel method or directly by Degussa P25 oxide and their surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The effect of adsorption of the cis-[Ru(dcbH2)2(NCS)2] dye, N3, on the surface of films was investigated. From XPS spectra taken before and after argon-ion sputtering procedure, the surface composition of inner and outer layers of sensitized films was obtained and a preferential etching of Ru peak in relation to the Ti and N ones was identified. The photoelectrochemical parameters were also evaluated and rationalized in terms of the morphological characteristics of the films

  11. Influence of contaminations on the performance of thin-film silicon solar cells prepared after in situ reactor plasma cleaning

    This paper addresses the influence of the chemical memory effect (CME) of in situ plasma cleaning by using the fluorinated gases on the properties of subsequently deposited thin-film silicon solar cells and discusses methods to avoid or reduce this effect. Secondary ion mass spectrometry (SIMS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) profiles analysis showed a high impurity concentration in the intrinsic (i)-layer of p-i-n solar cells prepared directly after in situ cleaning. With increasing number of cell depositions these contaminations decrease and the solar cell performance recovers to the standard value. Restoring solar cell performance is accompanied by a decrease of contaminants concentration in the i-layer. The intentional variation of the F-content in the i-layer obtained by adding SiF4 to the process gas mixture during a-Si:H i-layer preparation reveals that for solar cells a fluorine content above 1.5 x 1019 cm-3 is critical. We applied NF3 or SF6 + O2 as cleaning gases and optimized the cleaning procedure. In case of using NF3 as the cleaning gas, the CME was less pronounced as compared to the SF6 + O2 case and by additional procedures, like increasing the total gas flow rate during deposition, hydrogen plasma treatment of reaction chamber, the high solar cell quality could be achieved directly after in situ reactor cleaning. Low concentration of impurities in such cells was observed. Also the long-term illumination test (light-soaking for 1000 h, AM1.5 radiation) shows the same stabilized efficiency as compared to reference cells

  12. Significant light absorption enhancement in silicon thin film tandem solar cells with metallic nanoparticles

    Cai, Boyuan; Li, Xiangping; Zhang, Yinan; Jia, Baohua

    2016-05-01

    Enhancing the light absorption in microcrystalline silicon bottom cell of a silicon-based tandem solar cell for photocurrent matching holds the key to achieving the overall solar cell performance breakthroughs. Here, we present a concept for significantly improving the absorption of both subcells simultaneously by simply applying tailored metallic nanoparticles both on the top and at the rear surfaces of the solar cells. Significant light absorption enhancement as large as 56% has been achieved in the bottom subcells. More importantly the thickness of the microcrystalline layer can be reduced by 57% without compromising the optical performance of the tandem solar cell, providing a cost-effective strategy for high performance tandem solar cells.

  13. Significant light absorption enhancement in silicon thin film tandem solar cells with metallic nanoparticles.

    Cai, Boyuan; Li, Xiangping; Zhang, Yinan; Jia, Baohua

    2016-05-13

    Enhancing the light absorption in microcrystalline silicon bottom cell of a silicon-based tandem solar cell for photocurrent matching holds the key to achieving the overall solar cell performance breakthroughs. Here, we present a concept for significantly improving the absorption of both subcells simultaneously by simply applying tailored metallic nanoparticles both on the top and at the rear surfaces of the solar cells. Significant light absorption enhancement as large as 56% has been achieved in the bottom subcells. More importantly the thickness of the microcrystalline layer can be reduced by 57% without compromising the optical performance of the tandem solar cell, providing a cost-effective strategy for high performance tandem solar cells. PMID:27040376

  14. Steady state minority carrier lifetime and defect level occupation in thin film CdTe solar cells

    Cheng, Zimeng; Delahoy, Alan E.; Su, Zhaoqian; Chin, Ken K.

    2014-05-02

    A model consisting of Shockley Read Hall (SRH) recombination under steady state conditions of constant photon injection is proposed in this work to study the steady state minority carrier lifetime in CdS/CdTe thin film solar cells. The SRH recombination rate versus optical injection level is analytically approximated in the junction and neutral regions. In the neutral region, it is found that the recombination rate through certain defect levels has one constant value under lower optical injection conditions and another constant value under higher optical injection conditions with the transition occurring at a critical optical injection level. By simultaneously solving the equations of charge neutrality, charge conservation and SRH recombination in the neutral region, it is found that the compensation of doping and the reduction of minority carrier lifetime by donors in the p-type semiconductor can each be remedied by optical injection. It is also demonstrated that this optical-dependent SRH recombination is significant in large bandgap thin films. The measured minority carrier diffusion length in a CdS/CdTe solar cells, as determined from the steady-state photo-generated carrier collection efficiency, shows the predicted transition of minority carrier lifetime versus optical injection level. A numerical fitting of the indirectly-measured minority carrier lifetime by assuming the minority carrier mobility gives a non-intuitive picture of the p–n junction with a low free hole concentration but a narrow depletion region width. - Highlights: • Minority carrier lifetimes under different optical injections are solved. • Simplifications of Shockley–Read–Hall recombination equation are discussed. • The compensation of donor can be remedied with optical injection. • The recombination efficiency of donor can be remedied with optical injection. • The minority carrier lifetime transition under illumination was experimentally observed.

  15. Steady state minority carrier lifetime and defect level occupation in thin film CdTe solar cells

    A model consisting of Shockley Read Hall (SRH) recombination under steady state conditions of constant photon injection is proposed in this work to study the steady state minority carrier lifetime in CdS/CdTe thin film solar cells. The SRH recombination rate versus optical injection level is analytically approximated in the junction and neutral regions. In the neutral region, it is found that the recombination rate through certain defect levels has one constant value under lower optical injection conditions and another constant value under higher optical injection conditions with the transition occurring at a critical optical injection level. By simultaneously solving the equations of charge neutrality, charge conservation and SRH recombination in the neutral region, it is found that the compensation of doping and the reduction of minority carrier lifetime by donors in the p-type semiconductor can each be remedied by optical injection. It is also demonstrated that this optical-dependent SRH recombination is significant in large bandgap thin films. The measured minority carrier diffusion length in a CdS/CdTe solar cells, as determined from the steady-state photo-generated carrier collection efficiency, shows the predicted transition of minority carrier lifetime versus optical injection level. A numerical fitting of the indirectly-measured minority carrier lifetime by assuming the minority carrier mobility gives a non-intuitive picture of the p–n junction with a low free hole concentration but a narrow depletion region width. - Highlights: • Minority carrier lifetimes under different optical injections are solved. • Simplifications of Shockley–Read–Hall recombination equation are discussed. • The compensation of donor can be remedied with optical injection. • The recombination efficiency of donor can be remedied with optical injection. • The minority carrier lifetime transition under illumination was experimentally observed

  16. Spray Deposited Thin Film Metal Oxide Based Heterojunction for Solar Cell Application

    John Bosco Balaguru Rayappan

    2012-01-01

    Full Text Available In the present study, thin film heterojunction based on n-CdO/p-NiO was fabricated on glass substrate by home built spray pyrolysis technique under optimized condition. Cadmium acetate dihydrate and Nickel chloride were used as precursors. Structural, surface morphology, optical and photovoltaic properties were analyzed and reported.

  17. Nano-level characterization of silicon thin films and solar cells

    Fejfar, Antonín

    Tokyo : Ohmsha, 2013 - (Konagai, M.), s. 468-478 ISBN 978-4-274-21399-1 R&D Projects: GA MŠk(CZ) LM2011026 Grant ostatní: AVČR(CZ) M100101217 Institutional support: RVO:68378271 Keywords : silicon * thin films * atomic force microscopy * photoresponse Subject RIV: BM - Solid Matter Physics ; Magnetism

  18. The investigation of ZnO:Al2O3/metal composite back reflectors in amorphous silicon germanium thin film solar cells

    Different aluminum-doped ZnO (AZO)/metal composite thin films, including AZO/Ag/Al, AZO/Ag/nickelchromium alloy (NiCr), and AZO/Ag/NiCr/Al, are utilized as the back reflectors of pin amorphous silicon germanium thin film solar cells. NiCr is used as diffusion barrier layer between Ag and Al to prevent mutual diffusion, which increases the short circuit current density of solar cell. NiCr and NiCr/Al layers are used as protective layers of Ag layer against oxidation and sulfurization, the higher efficiency of solar cell is achieved. The experimental results show that the performance of a-SiGe solar cell with AZO/Ag/NiCr/Al back reflector is best. The initial conversion efficiency is achieved to be 8.05%

  19. Solar control on irradiated Ta2O2 thin films

    Thin films consisting of Ta2O5 have been used in industry in applications related to thin-film capacitors, optical waveguides, and antireflection coatings on solar cells. Ta2O5 films are used for several special applications as highly refractive material and show different optical properties depending on the deposition methods. Sol-gel technique has been used for the preparation of Ta2O5 thin films. Ta2O5 thin films were prepared by sol-gel proses on glass substrates to obtain good quality films. These films were exposed to gamma radiation from Co-60 radioisotope. Ta2O5 coated thin films were placed against the source and irradiated for 8 different gamma doses; between 0.35 and 21.00 kGy at room temperature. Energetic gamma ray can affect the samples and change its colour. On the other hand some of the Ta2O5 coated thin films were irradiated with beta radiation from Sr-90 radioisotope. The effect of gamma irradiation on the solar properties of Ta2O5 films is compared with that of beta irradiation. The solar properties of the irradiated thin films differ significantly from those of the unirradiated ones. After the irradiation of the samples transmittance and reflectance are measured for solar light between 300 and 2100 nm, by using Perkin Elmer Lambda 9 UV/VIS/NIR Spectrophotometer. Change in the direct solar transmittance, reflectance and absorptance with absorbed dose are determined. Using the optical properties, the redistribution of the absorbed component of the solar radiation and the shading coefficient (SC) are calculated as a function of the convective heat-transfer coefficient. Solar parameters are important for the determination of the shading coefficient. When the secondary internal heat transfer factor (qi), direct solar transmittance (□e), and solar factor (g) are known, it is possible to determine shading coefficient via the dose rates. The shading coefficient changes as the dose rate is increased. In this study, the shading coefficient is related to the colour centres, which are both present as intrinsic defects in structure and created induced defects by irradiation. The optical absorption bands were investigated depending on the gamma and beta irradiation. The changes of solar properties on irradiated Ta2O5 films are associated with the formation of defect centers and radiolytic electrons or holes. Under irradiation, the defects centers are formed as a result of charge trapping by radiolytic electrons or holes. It can be said that the control of solar energy is possible while the shading coefficient decreases in the irradiation condition

  20. Preparation and Characterization of Cu2ZnSnS4 Thin Films and Solar Cells Fabricated from Quaternary Cu-Zn-Sn-S Target

    Min Xie; Daming Zhuang; Ming Zhao; Zuolong Zhuang; Liangqi Ouyang; Xiaolong Li; Jun Song

    2013-01-01

    CZTS thin films were fabricated through sputtering from a quaternary Cu-Zn-Sn-S target, followed by a sulfurization process. CZTS thin-film solar cells were also fabricated and a highest efficiency of 4.04% was achieved. It has been found that obvious Zn loss occurs during the sputtering and poorly crystallized CZTS are formed in the sputtered films. The Zn loss leads to the appearance of SnS. A sulfurization process can obviously improve the crystallinity of CZTS and films with grain size of...