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Sample records for thin-film solar cells

  1. Thin-film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Aberle, Armin G., E-mail: armin.aberle@nus.edu.s [Solar Energy Research Institute of Singapore, Department of Electrical and Computer Engineering, National University of Singapore (Singapore)

    2009-07-01

    The rapid progress that is being made with inorganic thin-film photovoltaic (PV) technologies, both in the laboratory and in industry, is reviewed. While amorphous silicon based PV modules have been around for more than 20 years, recent industrial developments include the first polycrystalline silicon thin-film solar cells on glass and the first tandem solar cells based on stacks of amorphous and microcrystalline silicon films ('micromorph cells'). Significant thin-film PV production levels are also being set up for cadmium telluride and copper indium diselenide.

  2. Thin-film solar cells

    International Nuclear Information System (INIS)

    The rapid progress that is being made with inorganic thin-film photovoltaic (PV) technologies, both in the laboratory and in industry, is reviewed. While amorphous silicon based PV modules have been around for more than 20 years, recent industrial developments include the first polycrystalline silicon thin-film solar cells on glass and the first tandem solar cells based on stacks of amorphous and microcrystalline silicon films ('micromorph cells'). Significant thin-film PV production levels are also being set up for cadmium telluride and copper indium diselenide.

  3. Thin-film solar cell:

    OpenAIRE

    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...

  4. Silicon Thin-Film Solar Cells

    OpenAIRE

    Guy Beaucarne

    2007-01-01

    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 t...

  5. Deposition techniques for thin film solar cells

    International Nuclear Information System (INIS)

    Because of their high conversion efficiencies (?11%) reported in recent years, polycrystalline thin film solar cells have become strong contenders for low-cost solar electric generators (also known as photovoltaic modules). The low-cost potential for thin film solar cells has been recognized for quite sometimes. Because of this feature, amorphous silicon solar cells emerged in late seventies as potential candidates for mass scale production of solar modules and attracted significant interest and activity. During this period the efforts for the development thin film polycrystalline solar cells were rather limited. However, amorphous silicon solar cells have been observed to be unstable. This paper attempts briefly, to review the merits and short falls of various techniques for their suitability for large scale production solar modules

  6. Printable CIGS thin film solar cells

    Science.gov (United States)

    Fan, Xiaojuan

    2014-03-01

    Among the various thin film solar cells in the market, CuInGaSe thin film cells have been considered as the most promising alternatives to silicon solar cells because of their high photo-electricity efficiency, reliability, and stability. However, many fabrication of CIGS thin film are based on vacuum processes such as evaporation sputtering techniques which are not cost efficient. This work develops a method using paste or ink liquid spin-coated on glass that would be to conventional ways in terms of cost effective, non-vacuum needed, quick processing. A mixture precursor was prepared by dissolving appropriate amounts of chemicals. After the mixture solution was cooled, a viscous paste prepared and ready for spin-coating process. A slight bluish CIG thin film substrate was then put in a tube furnace with evaporation of metal Se by depositing CdS layer and ZnO nanoparticle thin film coating to a solar cell fabrication. Structure, absorption spectrum, and photo-conversion efficiency for the as-grown CIGS thin film solar cell under study.

  7. Advances in thin-film solar cells

    CERN Document Server

    Dharmadasa, I M

    2012-01-01

    This book concentrates on the latest developments in our understanding of solid-state device physics. The material presented is mainly experimental and based on CdTe thin-film solar cells. It extends these new findings to CIGS thin-film solar cells and presents a new device design based on graded bandgap multilayer solar cells. This design has been experimentally tested using the well-researched GaAs/AlGaAs system and initial devices have shown impressive device parameters. These devices are capable of absorbing all radiation (UV, visible, and infra-red) within the solar spectrum and combines

  8. Thin film solar cell technology in Germany

    International Nuclear Information System (INIS)

    Within the scope of limited nonrenewable energy resources and the limited capacity of the ecosystem for greenhouse gases and nuclear waste, sustainability is one important target in the future. Different energy scenarios showed the huge potential for photovoltaics (PV) to solve this energy problem. Nevertheless, in the last decade, PV had an average growth rate of over 20% per year. In 2002, the solar industry delivered more than 500 MWp/year of photovoltaic generators [A. Jaeger-Waldau, A European Roadmap for PV R and D, E-MRS Spring Meeting, (2003)]. More than 85% of the current production involves crystalline silicon technologies. These technologies still have a high cost reduction potential, but this will be limited by the silicon feedstock. On the other hand the so-called second generation thin film solar cells based on a-Si, Cu(In,Ga)(Se,S2 (CIGS) or CdTe have material thicknesses of a few microns as a result of their direct band gap. Also, the possibility of circuit integration offers an additional cost reduction potential. Especially in Germany, there are a few companies who focus on thin film solar cells. Today, there are two manufacturers with production lines: the Phototronics (PST) division of RWE-Schott Solar with a-Si thin film technology and the former Antec Solar GmbH (now Antec Solar Energy GmbH) featuring the CdTe technology. A pilot line based on CIGS technology is run by Wuerth Solar GmbH. There is also a variety of research activity at is also a variety of research activity at other companies, namely, at Shell Solar, Sulfurcell Solartechnik GmbH, Solarion GmbH and the CIS-Solartechnik GmbH. We will give an overview on research activity on various thin film technologies, as well as different manufacturing and production processes in the companies mentioned above. (Author)

  9. Light management in thin-film silicon solar cells:

    OpenAIRE

    Isabella, O.

    2013-01-01

    Solar energy can fulfil mankind’s energy needs and secure a more balanced distribution of primary sources of energy. Wafer-based and thin-film silicon solar cells dominate todays’ photovoltaic market because silicon is a non-toxic and abundant material and high conversion efficiencies are achieved with silicon-based solar cells. To stay competitive with bulk crystalline silicon and other thin-film solar cell technologies, thin-film silicon solar cells have to achieve a conversion efficie...

  10. Thin-film silicon solar cell technology

    Energy Technology Data Exchange (ETDEWEB)

    Shah, A.V.; Meier, J.; Kroll, U.; Droz, C.; Bailat, J. [University of Neuchatel (Switzerland). Inst. of Microtechnology; Schade, H. [RWE Schott Solar GmbH, Putzbrunn (Germany); Vanecek, M. [Academy of Sciences, Prague (Czech Republic). Inst. of Physics; Vallat Sauvain, E.; Wyrsch, N. [University of Neuchatel (Switzerland). Inst. of Microtechnology; Unaxis SPTec S A, Neuchatel (Switzerland)

    2004-07-01

    This paper describes the use, within p-i-n- and n-i-p-type solar cells, of hydrogenated amorphous silicon (a-Si:H) and hydrogenated microcrystalline silicon ({mu}c-Si:H) thin films (layers), both deposited at low temperatures (200{sup o}C) by plasma-assisted chemical vapour deposition (PECVD), from a mixture of silane and hydrogen. Optical and electrical properties of the i-layers are described. These properties are linked to the microstructure and hence to the i-layer deposition rate, that in turn, affects throughput in production. The importance of contact and reflection layers in achieving low electrical and optical losses is explained, particularly for the superstrate case. Especially the required properties for the transparent conductive oxide (TCO) need to be well balanced in order to provide, at the same time, for high electrical conductivity (preferably by high electron mobility), low optical absorption and surface texture (for low optical losses and pronounced light trapping). Single-junction amorphous and microcrystalline p-i-n-type solar cells, as fabricated so far, are compared in their key parameters (J{sub sc},FF,V{sub oc}) with the [theoretical] limiting values. Tandem and multijunction cells are introduced; the {mu}c-Si: H/a-Si: H or [micromorph] tandem solar cell concept is explained in detail, and recent results obtained here are listed and commented. Factors governing the mass-production of thin-film silicon modules are determined both by inherent technical reasons, described in detail, and by economic considerations. The cumulative effect of these factors results in distinct efficiency reductions from values of record laboratory cells to statistical averages of production modules. Finally, applications of thin-film silicon PV modules, especially in building-integrated PV (BIPV) are shown. In this context, the energy yields of thin-film silicon modules emerge as a valuable gauge for module performance, and compare very favourably with those of other PV technologies. (author)

  11. Silicon Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    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.

  12. Polycrystalline thin-film solar cells

    International Nuclear Information System (INIS)

    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

  13. Thin Film Solar Cells: Research in an Industrial Perspective

    OpenAIRE

    Edoff, Marika

    2012-01-01

    Electricity generation by photovoltaic conversion of sunlight is a technology in strong growth. The thin film technology is taking market share from the dominant silicon wafer technology. In this article, the market for photovoltaics is reviewed, the concept of photovoltaic solar energy conversion is discussed and more details are given about the present technological limitations of thin film solar cell technology. Special emphasis is given for solar cells which employ Cu(In,Ga)Se2 and Cu2ZnS...

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

    CERN Document Server

    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

  15. Broadband back grating design for thin film solar cells

    KAUST Repository

    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.

  16. UV imprinting for thin film solar cell application

    OpenAIRE

    Escarre, J.; Battaglia, C.; Soederstroem, K; Pahud, C.; Biron, R.; Cubero, O.; Haug, F.-J; Ballif, C.

    2012-01-01

    UV imprinting is an interesting, low cost technique to produce large area thin film solar cells incorporating nanometric textures. Here, we review and present new results confirming that replicas of the most common textures used in photovoltaics can be obtained by UV imprinting with an excellent fidelity. The use of these replicas as substrates for amorphous and micromorph thin film silicon solar cells is also shown, together with a comparison with devices obtained on the original textures.

  17. UV imprinting for thin film solar cell application

    International Nuclear Information System (INIS)

    UV imprinting is an interesting, low cost technique to produce large area thin film solar cells incorporating nanometric textures. Here, we review and present new results confirming that replicas of the most common textures used in photovoltaics can be obtained by UV imprinting with an excellent fidelity. The use of these replicas as substrates for amorphous and micromorph thin film silicon solar cells is also shown, together with a comparison with devices obtained on the original textures

  18. UV imprinting for thin film solar cell application

    Science.gov (United States)

    Escarré, J.; Battaglia, C.; Söderström, K.; Pahud, C.; Biron, R.; Cubero, O.; Haug, F.-J.; Ballif, C.

    2012-02-01

    UV imprinting is an interesting, low cost technique to produce large area thin film solar cells incorporating nanometric textures. Here, we review and present new results confirming that replicas of the most common textures used in photovoltaics can be obtained by UV imprinting with an excellent fidelity. The use of these replicas as substrates for amorphous and micromorph thin film silicon solar cells is also shown, together with a comparison with devices obtained on the original textures.

  19. Efficient light trapping structure in thin film silicon solar cells

    OpenAIRE

    Sheng, Xing; Liu, Jifeng; Kozinsky, Inna; Michel, Jurgen; Kimerling, Lionel C.; Agarwal, Anuradha Murthy

    2010-01-01

    Thin film silicon solar cells are believed to be promising candidates for continuing cost reduction in photovoltaic panels because silicon usage could be greatly reduced. Since silicon is an indirect bandgap semiconductor, its absorption coefficient is low for photons in the wavelength ranges between 600nm and 1100nm. For high efficiency thin film modules, effective light trapping is essential. Traditional schemes such as textured transparent conductive oxide (TCO) and metal reflector have se...

  20. Single Source Precursors for Thin Film Solar Cells

    Science.gov (United States)

    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.

  1. Development of A Thin Film Crystalline Silicon Solar Cell

    International Nuclear Information System (INIS)

    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

  2. Thin Film Solar Cells and their Optical Properties

    Directory of Open Access Journals (Sweden)

    Robert Brunner

    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.

  3. Low cost thin film poly-silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This report presents the results of a project to design and develop a high density plasma based thin-film poly-silicon (TFPS) deposition system based on PQL proprietary advanced plasma technology to produce semiconductor quality TFPS for fabricating a TFPS solar cell. Details are given of the TFPS deposition system, the material development programme, solar cell structure, and cell efficiencies. The reproducibility of the deposition process and prospects for commercial exploitation are discussed.

  4. Laser annealing of thin film polycrystalline silicon solar cell

    OpenAIRE

    Chowdhury A; Bahouka A.; Steffens S.; Schneider J; Dore J.; Mermet F.; Slaoui A.

    2013-01-01

    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 im...

  5. Light trapping effects in thin film silicon solar cells

    OpenAIRE

    Haug, Fj; So?derstro?m, T.; Domine?, D.; Ballif, C.

    2009-01-01

    We present advanced light trapping concepts for thin film silicon solar cells. When an amorphous and a microcrystalline absorber layers are combined into a micromorph tandem cell, light trapping becomes a challenge because it should combine the spectral region from 600 to 750 nm for the amorphous top cell and from 800 to 1100 for the microcrystalline bottom cell. Because light trapping is typically achieved by growing on textured substrates, the effect of interface textures on the material an...

  6. Thin-film crystalline silicon solar cells

    CERN Document Server

    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.

  7. High efficiency thin-film GaAs solar cells

    Science.gov (United States)

    Stirn, R. J.

    1977-01-01

    Several oxidation techniques are discussed which have been found to increase the open circuit (V sub oc) of metal-GaAs Schottky barrier solar cells, the oxide chemistry, attempts to measure surface state parameters, the evolving characteristics of the solar cell as background contamination (has been decreased, but not eliminated), results of focused Nd/YAG laser beam recrystallization of Ge films evaporated onto tungsten, and studies of AMOS solar cells fabricated on sliced polycrystalline GaAs wafers. Also discussed are projected materials availability and costs for GaAs thin-film solar cells.

  8. TCAD simulations for thin film solar cells with nanoplate structures.

    Science.gov (United States)

    Chang, S T; Lin, W K; Liu, Y C

    2012-07-01

    The novel thin film solar cell with a nanoplate structure that can solve the conflict between the light absorption and the carrier transport in amorphous silicon thin film solar cell was investigated by TCAD simulations. This new structure has n-type amorphous silicon nanoplate array on the substrate, and p-type amorphous silicon-carbon as window layer and intrinsic amorphous silicon as absorption layer are sequentially grown along the surface of each n-type amorphous silicon nanoplate. Under AM 1.5 G sunlight illumination, the light is absorbed along the vertical direction of nanoplate while the carrier transport is along the horizontal direction. Therefore, nanoplate with the larger height can absorb most of the sunlight. The advantage of this novel structure is that the thickness of the solar cell can be used as thin as possible for effective transport of photo-generated carriers in comparison with the planer one. PMID:22966571

  9. Thin-film silicon solar cell technology.

    Czech Academy of Sciences Publication Activity Database

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

    2004-01-01

    Ro?. 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 * hydrogenerated amorphous silicon(a-Si:H) * hydrogenerated microcrystalline (?c-Si:H) * transparent conductive oxydes(TCOs) * building - integrated photovoltaics ( BIPV ) Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.196, year: 2004

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

    Science.gov (United States)

    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.

  11. Optical confinement in recrystallised wafer equivalent thin film solar cells

    OpenAIRE

    Janz, S.; Kuenle, M.; Peters, M.; Lindekugel, S.; Mitchell, E. J.; Reber, S.

    2007-01-01

    Bragg reflectors were used to enhance rear-side optical confinement in crystalline silicon thin film solar cells. Besides the enhancement of reflectivity in the long wavelength region, the layer stack acts as a diffusion barrier. We designed two different Bragg reflectors which were deposited on different silicon substrates. By adjusting the thickness of the single layers and their refractive indices an optimum reflected wavelength region exceeding 800 nm can be created. The amount of reflect...

  12. TCOs for nip thin film silicon solar cells

    OpenAIRE

    Söderström, T.; Haug, F-J; Niquille, X; Ballif, C.

    2009-01-01

    Substrate configuration allows for the deposition of thin film silicon (Si) solar cells on non-transparent substrates such as plastic sheets or metallic foils. In this work, we develop processes compatible with low Tg plastics. The amorphous Si (a-Si:H) and microcrystalline Si (µc-Si:H) films are deposited by plasma enhanced chemical vapour deposition, at very high excitation frequencies (VHF-PECVD). We investigate the optical behaviour of single and triple ju...

  13. Nanowired Polymer Thin Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Dr. K. Siddappa Naidu1 , Dr. D. Bhattacharya2 , Mr. Vijay Albert William3

    2013-12-01

    Full Text Available The aspiration of the paper is to build up materials and processing techniques that will allow the production of low-cost multi-junction solar cells entirely by solution-processing or other low-cost techniques amenable to roll-to-roll (R2R fabrication such as lamination. Device modeling will help identify the best device structural design. Amalgamation of different types of materials (metals, oxides, semiconductors, polymers is one of the goals of this project.

  14. Transparent Conductive Oxides for Thin-Film Silicon Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Loeffler, J.

    2005-04-25

    This thesis describes research on thin-film silicon solar cells with focus on the transparent conductive oxide (TCO) for such devices. In addition to the formation of a transparent and electrically conductive front electrode for the solar cell allowing photocurrent collection with low ohmic losses, the front TCO plays an important role for the light enhancement of thin-film silicon pin type solar cells. If the TCO is rough, light scattering at rough interfaces in the solar cell in combination with a highly reflective back contact leads to an increase in optical path length of the light. Multiple (total) internal reflectance leads to virtual 'trapping' of the light in the solar cell structure, allowing a further decrease in absorber thickness and thus thin-film silicon solar cell devices with higher and more stable efficiency. Here, the optical mechanisms involved in the light trapping in thin-film silicon solar cells have been studied, and two types of front TCO materials have been investigated with respect to their suitability as front TCO in thin-film silicon pin type solar cells. Undoped and aluminum doped zinc oxide layers have been fabricated for the first time by the expanding thermal plasma chemical vapour deposition (ETP CVD) technique at substrate temperatures between 150C and 350C, and successfully implemented as a front electrode material for amorphous silicon pin superstrate type solar cells. Solar cells with efficiencies comparable to cells on Asahi U-type reference TCO have been reproducibly obtained. A higher haze is needed for the ZnO samples studied here than for Asahi U-type TCO in order to achieve comparable long wavelength response of the solar cells. This is attributed to the different angular distribution of the scattered light, showing higher scattering intensities at large angles for the Asahi U-type TCO. A barrier at the TCO/p interface and minor collection problems may explain the slightly lower fill factors obtained for the cells on ETP ZnO. The solar cells deposited on the first doped ZnO:Al layers suffered from collection problems reducing the fill factor, and from shunting. This is attributed to the steep trenches, sharp features and vertical steps that have been identified at the TCO surface. ZnO:Al layers with granular structure, deposited at higher argon flow through the cascaded arc plasma source, allowed for fill factors of the solar cells up to 0.70, comparable to cells on undoped ZnO. The best solar cell on doped ZnO:Al deposited by ETP CVD achieved an efficiency of 9.3 % which is comparable to the 9.4 % obtained on Asahi U-type SnO2:F. Fluorinated tin oxide has been deposited by Atmospheric Chemical Vapor Deposition (APCVD) on glass from three different tin precursors, tetramethyltin, monobutyltin trichloride, and tin tetrachloride (TTC). TTC is the Sn precursor which resulted in the TCO with the best performance of a-Si:H pin solar cells. In accordance with the conclusions from our experiments with solar cells on undoped and aluminum doped zinc oxide, a high surface roughness and haze do not necessarily lead to a lower diode quality, and vice versa.

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

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Mortensen, N. Asger

    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-film semiconducting material. For a particular case, we show that coupling to the same type of localized slab-waveguide modes can be obtained by a surface modulation consisting of purely dielectric strips. The purely dielectric device turns out to have a significantly higher broadband enhancement factor compared to its metallic counterpart. We show that the enhanced normalized short-circuit current for a cell with silicon strips can be increased 4 times compared to the best performance for strips of silver, gold, or aluminium. For this particular case, the simple dielectric grating may outperform its plasmonic counterpart due to the larger Ohmic losses associated with the latter.

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

    CERN Document Server

    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

  17. Laser annealing of thin film polycrystalline silicon solar cell

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    Czech Academy of Sciences Publication Activity Database

    Van??ek, Milan; Neykova, Neda; Babchenko, Oleg; Purkrt, Adam; Poruba, Aleš; Remeš, Zden?k; 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 Grant ostatní: EU FP7 N2P(XE) CP-IP 214134-2 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

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

    Science.gov (United States)

    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.

  1. Development of CIGS2 thin film solar cells

    International Nuclear Information System (INIS)

    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 diltion 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

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

    Directory of Open Access Journals (Sweden)

    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.

  3. ???????????????? Optimization of Amorphous Silicon Thin Film Solar Cells Production Process

    Directory of Open Access Journals (Sweden)

    ???

    2011-03-01

    Full Text Available ???????????????????????????????AZO???????Al???????????????????????????????????Minitab?????????????????????????????????????????????????Al???????????????????????????????????????????????AZO??????????Ar?????????????????????????????????????????????????????During the glass substrate amorphous silicon thin film solar cell production process, the laser scribe 2, sputtering AZO back reflected film, sputtering Al film, and laser scribe 3 etc. processes, have great effect on the maximum power (Pmax of the solar cell. In this paper, we use Minitab software to design factorial experiment and optimize the process parameters. By analyzing the experimental data, we get the conclusion that, between an acceptable range, the sputtering power of Al film has the greatest effect on the Pmax of the solar cell, which increases while the sputtering power increases?and the Pmax increases as the current of laser scribe 3, puttering power of Al films and flux of Ar increase. Otherwise, Pmax decreases as the current of laser scribe 2 increases. By using the factorial experiment, we get the optimum parameters of the process for the present production line.

  4. Transmission electron microscopy for thin film solar cells

    International Nuclear Information System (INIS)

    Thin-film amorphous and microcrystalline silicon are promising materials for photovoltaics as they have the potential to reduce the solar cell costs. In case of microcrystalline silicon the crystalline volume fraction is related to the efficiency factor of solar cells because it provides information about the microstructure of the material and the defect density. With Transmission Electron Microscopy of cross-sections it is possible to show the microstructure of the cells. However to determine the structure of the bulk it is necessary to analyse the diffraction of the electron beam. For the purpose of imaging diffraction patterns and displaying dark fields a new camera system has been installed in the Phillips CM200. With much higher sensitivity and a larger photoactive area it is possible to take images of the low-intensity diffraction and the dark field patterns.

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

    International Nuclear Information System (INIS)

    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

  6. Sputter-Deposited AlTiO Thin Films for Semi-Transparent Silicon Thin Film Solar Cells

    Science.gov (United States)

    Lee, Seung-Yun; Bang, Ki Su; Lim, Jung Wook

    2014-09-01

    This paper reports on sputter-deposited AlTiO (ATO) thin films and their effects on the performance of semi-transparent silicon thin film solar cells. The electrical resistivity and the transparency of the ATO films depend significantly on the flow ratio of oxygen to argon during the reactive sputtering process. With highly transparent ATO films, transmittances of over 80% were obtained by increasing this flow ratio. When the ATO films were used on silicon substrates, they exhibited an anti-reflection property, where the minimum reflectance at visible light wavelength was decreased to 1.2%. The introduction of ATO thin film layers into solar cells resulted in a 24% increase in transmittance at wavelengths of around 700 nm, due to the film's anti-reflection characteristic. In addition, the color of the cells changed from green to bright red as the ATO layers were adopted. These beneficial effects of the sputter-deposited ATO films suggest an effective pathway towards the semi-transparent silicon thin film solar cells for building-integrated photovoltaic system applications.

  7. Flexible carbon nanotube/mono-crystalline Si thin-film solar cells

    Science.gov (United States)

    Sun, Huanhuan; Wei, Jinquan; Jia, Yi; Cui, Xian; Wang, Kunlin; Wu, Dehai

    2014-09-01

    Flexible heterojunction solar cells were fabricated from carbon nanotubes (CNTs) and mono-crystalline Si thin films at room temperature. The Si thin films with thickness less than 50 ?m are prepared by chemically etching Si wafer in a KOH solution. The initial efficiency of the thin-film solar cell varies from approximately 3% to 5%. After doping with a few drops of 1 M HNO3, the efficiency increases to 6% with a short-circuit current density of 16.8 mA/cm2 and a fill factor of 71.5%. The performance of the solar cells depends on the surface state and thickness of Si thin films, as well as the interface of CNT/Si. The flexible CNT/Si thin-film solar cells exhibit good stability in bending-recovery cycles.

  8. Potential of thin-film solar cell module technology

    Science.gov (United States)

    Shimada, K.; Ferber, R. R.; Costogue, E. N.

    1985-01-01

    During the past five years, thin-film cell technology has made remarkable progress as a potential alternative to crystalline silicon cell technology. The efficiency of a single-junction thin-film cell, which is the most promising for use in flat-plate modules, is now in the range of 11 percent with 1-sq cm cells consisting of amorphous silicon, CuInSe2 or CdTe materials. Cell efficiencies higher than 18 percent, suitable for 15 percent-efficient flat plate modules, would require a multijunction configuration such as the CdTe/CuInSe2 and tandem amorphous-silicon (a-Si) alloy cells. Assessments are presented of the technology status of thin-film-cell module research and the potential of achieving the higher efficiencies required for large-scale penetration into the photovoltaic (PV) energy market.

  9. Numerical modeling of thin film Si:H solar cells

    International Nuclear Information System (INIS)

    A detailed numerical model incorporating exponential tail states and Gaussian-distributed dangling bond states and doping states in the gap is used to compute the performance characteristics of thin film Si:H solar cells. A one-to-one relationship between four-fold coordinated doping atoms and dangling bonds is included. A good match to experiment occurs if the front contact is treated as non-ohmic (i.e. with a non-infinite surface recombination velocity) and a critical capture cross section is taken much smaller than expected. The numerical model is also used to compute the dependence of dark conductivity on doping, which exhibits saturation at high doping levels as observed

  10. Boron-doped nanocrystalline silicon thin films for solar cells

    International Nuclear Information System (INIS)

    This article reports on the structural, electronic, and optical properties of boron-doped hydrogenated nanocrystalline silicon (nc-Si:H) thin films. The films were deposited by plasma-enhanced chemical vapour deposition (PECVD) at a substrate temperature of 150 deg. C. Crystalline volume fraction and dark conductivity of the films were determined as a function of trimethylboron-to-silane flow ratio. Optical constants of doped and undoped nc-Si:H were obtained from transmission and reflection spectra. By employing p+ nc-Si:H as a window layer combined with a p' a-SiC buffer layer, a-Si:H-based p-p'-i-n solar cells on ZnO:Al-coated glass substrates were fabricated. Device characteristics were obtained from current-voltage and spectral-response measurements.

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

    Science.gov (United States)

    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.

  12. Thin film, concentrator, and multijunction space solar cells: Status and potential

    Science.gov (United States)

    Flood, Dennis J.

    1991-01-01

    Recent, rapid advances in a variety of solar cell technologies offer the potential for significantly enhancing, or enabling entirely new, mission capabilities. Thin film solar cells are of particular interest. A review is provided of the status of those thin film cell technologies of interest for space applications, and the issues to be resolved before mission planners can consider them. A short summary of recent developments in concentrator and multijunction space solar cell and array technology is given.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    Science.gov (United States)

    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.

  16. Impedance spectroscopy of CdTe thin film solar cells

    International Nuclear Information System (INIS)

    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.

  17. Progress in Polycrystalline Thin-Film Cu(In,Ga)Se2 Solar Cells

    OpenAIRE

    Singh, Udai P.; Patra, Surya P.

    2010-01-01

    For some time, the chalcopyrite semiconductor CuInSe2 and its alloy with Ga and/or S [Cu(InGa)Se2 or Cu(InGa)(Se,S)2], 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 dep...

  18. Scribing of a-Si thin-film solar cells with picosecond laser

    OpenAIRE

    Gec?ys, P.; Rac?iukaitis, G.

    2010-01-01

    Abstract The thin-film technology is the most promising technology to achieve a significant cost reduction in solar electricity. Laser scribing is an important step to preserve high efficiency of photovoltaic devices on large areas. The high-repetition-rate laser with the pulse duration of 10 ps was applied in selective ablation of multilayer thin-film a-Si solar cells deposited on flexible and rigid substrates. Two types of solar cells with flexible an...

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

    International Nuclear Information System (INIS)

    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

    International Nuclear Information System (INIS)

    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. Charge carrier dynamics in thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. The Mott transition and optimal performance of transparent conducting oxides in thin-film solar cells

    OpenAIRE

    Slocombe, D.; Porch, A.; Pepper, M.; Edwards, Pp

    2012-01-01

    The performance of thin-film solar cells is critically dependent upon the effective operation of transparent conducting oxide (TCO) layers, which play a significant role in both optical and electrical power transmission through these photovoltaic devices. In this article, we model the optical and electrical power transmission through TCO layers in thin-film solar cells as a function of both the electron carrier density, n, and its mobility, ?. The electrical and optical properties of the TCO...

  3. Flexible carbon nanotube/mono-crystalline Si thin-film solar cells

    OpenAIRE

    Sun, Huanhuan; Wei, Jinquan; Jia, Yi; Cui, Xian; Wang, Kunlin; Wu, Dehai

    2014-01-01

    Flexible heterojunction solar cells were fabricated from carbon nanotubes (CNTs) and mono-crystalline Si thin films at room temperature. The Si thin films with thickness less than 50 ?m are prepared by chemically etching Si wafer in a KOH solution. The initial efficiency of the thin-film solar cell varies from approximately 3% to 5%. After doping with a few drops of 1 M HNO3, the efficiency increases to 6% with a short-circuit current density of 16.8 mA/cm2 and a fill factor of 71.5%. The...

  4. A novel semiconductor material for the thin film solar cells

    International Nuclear Information System (INIS)

    Thin films of the novel alloy, mercury zinc telluride Hg/sub 1-x/Zn/sub x/Te have been produced in polycrystalline form by using the co-evaporation of zinc telluride (ZnTe) and mercury telluride (HgTe). The layers were produced with bandgaps in the range of 0.5 to 2.25 eV by altering the alloy composition. The absorption coefficient alpha, was found to be greater than 10/sup 5/cm/sup -1/ in samples with bandgaps greater than 1.5 eV. The as-grown layers were p-type at room temperature (300 K) with low resistivities between 0.16 to 0.55 to 0.45 micro m. Arrhenius plots of the resistivities gave two straight lines corresponding to an activation energy of 50 +- 5 MeV for temperatures greater than 220 K and an activation energy of 7 +- 4 MeV or temperatures than 220 K. The significance of these results regarding the potential of Hg/sub 1-x/Zn/sub x/Te alloys for their use in multijunction solar cells is discussed. (author)

  5. Advances in thin-film solar cells for lightweight space photovoltaic power

    Science.gov (United States)

    Landis, Geoffrey A.; Bailey, Sheila G.; Flood, Dennis J.

    1989-01-01

    The present stature and current research directions of photovoltaic arrays as primary power systems for space are reviewed. There have recently been great advances in the technology of thin-film solar cells for terrestrial applications. In a thin-film solar cell the thickness of the active element is only a few microns; transfer of this technology to space arrays could result in ultralow-weight solar arrays with potentially large gains in specific power. Recent advances in thin-film solar cells are reviewed, including polycrystalline copper-indium selenide (CuInSe2) and related I-III-VI2 compounds, polycrystalline cadmium telluride and related II-VI compounds, and amorphous silicon:hydrogen and alloys. The best experimental efficiency on thin-film solar cells to date is 12 percent AMO for CuIn Se2. This efficiency is likely to be increased in the next few years. The radiation tolerance of thin-film materials is far greater than that of single-crystal materials. CuIn Se2 shows no degradation when exposed to 1 MeV electrons. Experimental evidence also suggests that most of all of the radiation damage on thin-films can be removed by a low temperature anneal. The possibility of thin-film multibandgap cascade solar cells is discussed, including the tradeoffs between monolithic and mechanically stacked cells. The best current efficiency for a cascade is 12.5 percent AMO for an amorphous silicon on CuInSe2 multibandgap combination. Higher efficiencies are expected in the future. For several missions, including solar-electric propulsion, a manned Mars mission, and lunar exploration and manufacturing, thin-film photovolatic arrays may be a mission-enabling technology.

  6. Influence of CuxS back contact on CdTe thin film solar cells

    International Nuclear Information System (INIS)

    We present a detailed study on CuxS polycrystalline thin films prepared by chemical bath method and utilized as back contact material for CdTe solar cells. The characteristics of the films deposited on Si-substrate are studied by XRD. The results show that as-deposited CuxS thin film is in an amorphous phase while after annealing, samples are in polycrystalline phases with increasing temperature. The thickness of CuxS thin films has great impact on the performance of CdS/CdTe solar cells. When the thickness of the film is about 75 nm the performance of CdS/CdTe thin film solar cells is found to be the best. The energy conversion efficiency can be higher than 12.19%, the filling factor is higher than 68.82% and the open-circuit voltage is more than 820 mV. (semiconductor devices)

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

    International Nuclear Information System (INIS)

    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%.

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

    Directory of Open Access Journals (Sweden)

    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 ?/?cm2, and reflecting (~ 55 % Mo thin film was observed at 1 mTorr working pressure and 100 W RF power.

  9. Review of thin film solar cell technology and applications for ultra-light spacecraft solar arrays

    Science.gov (United States)

    Landis, Geoffrey A.

    1991-01-01

    Developments in thin-film amorphous and polycrystalline photovoltaic cells are reviewed and discussed with a view to potential applications in space. Two important figures of merit are discussed: efficiency (i.e., what fraction of the incident solar energy is converted to electricity), and specific power (power to weight ratio).

  10. Lead Iodide Thin Film Crystallization Control for High-Performance and Stable Solution-Processed Perovskite Solar Cells.

    Science.gov (United States)

    Yang, Lijun; Wang, Jingchuan; Leung, Wallace Woon-Fong

    2015-07-15

    PbI2 thin film crystallization control is a prerequisite of high-quality perovskite thin film for sequentially solution-processed perovskite solar cells. An efficient and simple method has been developed by adding HCl to improve perovskite thin film quality, and an efficiency of 15.2% is obtained. This approach improves coverage, uniformity, and stability of pervoskite thin film. PMID:26108296

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

    International Nuclear Information System (INIS)

    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)

  12. Hydrogen passivation of polycrystalline Si thin film solar cells

    International Nuclear Information System (INIS)

    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.)

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

    CERN Document Server

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

    International Nuclear Information System (INIS)

    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)

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

    Czech Academy of Sciences Publication Activity Database

    Olejní?ek, Ji?í; Hubi?ka, Zden?k; Kohout, Michal; Kšírová, Petra; Kment, Št?pán; Brunclíková, Michaela; ?ada, Martin; Darveau, S.A.; Exstrom, C.L.

    2014-01-01

    Ro?. 1, ?. 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

  16. Effects of phosphorous doping to poly (methylphenyl silane) and fabrication of thin film solar cells

    Science.gov (United States)

    Nakagawa, Junya; Oku, Takeo; Suzuki, Atsushi; Akiyama, Tsuyoshi; Tokumitsu, Katsuhisa; Yamada, Masahiro; Nakamura, Mika

    2013-04-01

    Effects of phosphorus bromine (PBr3) doping to polysilane were investigated for spin-coating thin films. Phosphorus doped poly (methylphenyl silane) (PMPS) provided n-type semiconductor behavior, which was confirmed by Hall effect measurements. Desorption of phenyl and methyl groups in doped PMPS thin films was observed after annealing at 300 °C from Raman scattering measurements and theoretical calculations. The band gap energy of PMPS was measured to be 3.2 eV. Decrease of photoluminescence intensity of PMPS was observed by phosphorus doping. Microstructures of the doped PMPS thin films were investigated by using X-ray diffraction, which indicated doped PMPS had an amorphous structure after annealing. A solar cell with PMPS(PBr3):poly[3-hexylthiophene] bulk-heterojunction structure was fabricated, and provided a photovoltaic behavior. Formation mechanism and carrier transport mechanism of the doped PMPS thin films were proposed.

  17. Effects of phosphorous doping to poly (methylphenyl silane) and fabrication of thin film solar cells

    International Nuclear Information System (INIS)

    Effects of phosphorus bromine (PBr3) doping to polysilane were investigated for spin-coating thin films. Phosphorus doped poly (methylphenyl silane) (PMPS) provided n-type semiconductor behavior, which was confirmed by Hall effect measurements. Desorption of phenyl and methyl groups in doped PMPS thin films was observed after annealing at 300 °C from Raman scattering measurements and theoretical calculations. The band gap energy of PMPS was measured to be 3.2 eV. Decrease of photoluminescence intensity of PMPS was observed by phosphorus doping. Microstructures of the doped PMPS thin films were investigated by using X-ray diffraction, which indicated doped PMPS had an amorphous structure after annealing. A solar cell with PMPS(PBr3):poly[3-hexylthiophene] bulk-heterojunction structure was fabricated, and provided a photovoltaic behavior. Formation mechanism and carrier transport mechanism of the doped PMPS thin films were proposed.

  18. Study on AlxNiy Alloys as Diffusion Barriers in Flexible Thin Film Solar Cells

    International Nuclear Information System (INIS)

    Co-sputtered AlxNiy thin films were used as diffusion barriers between aluminum and hydrogenated microcrystalline silicon (?c-Si:H) for flexible thin film solar cells. The stoichiometric ratio of AlxNiy showed a significant effect on the structures of the films. The obtained Al3Ni2 film was amorphous, while polycrystalline films were obtained when the ratio of aluminum to nickel was 1:1 and 2:3. An auger electron spectroscope and four-point probe system were applied to test the resistance to the interdiffusion between aluminum and silicon, as well as the conductivities of the AlxNiy barriers. The data of auger depth profile showed that the content of silicon was the minimum in the aluminum layer after sputtering for 4 min using AlNi thin film as the barrier layer. Compared to other AlxNiy alloys, the AlNi thin film possessed the lowest sheet resistance.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    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. Cost-effective nanostructured thin-film solar cell with enhanced absorption

    Science.gov (United States)

    Wang, Peng Hui; Nowak, Regina-Elisabeth; Geißendörfer, Stefan; Vehse, Martin; Reininghaus, Nies; Sergeev, Oleg; von Maydell, Karsten; Brolo, Alexandre G.; Agert, Carsten

    2014-11-01

    Nanostructured transparent conductive electrodes are highly interesting for efficient light management in thin-film solar cells, but they are often costly to manufacture and limited to small scales. This work reports on a low-cost and scalable bottom-up approach to fabricate nanostructured thin-film solar cells. A folded solar cell with increased optical absorber volume was deposited on honeycomb patterned zinc oxide nanostructures, fabricated in a combined process of nanosphere lithography and electrochemical deposition. The periodicity of the honeycomb pattern can be easily varied in the fabrication process, which allows structural optimization for different absorber materials. The implementation of this concept in amorphous silicon thin-film solar cells with only 100 nm absorber layer was demonstrated. The nanostructured solar cell showed approximately 10% increase in the short circuit current density compared to a cell on an optimized commercial textured reference electrode. The concept presented here is highly promising for low-cost industrial fabrication of nanostructured thin-film solar cells, since no sophisticated layer stacks or expensive techniques are required.

  2. Thin-film filament-based solar cells and modules

    Science.gov (United States)

    Tuttle, J. R.; Cole, E. D.; Berens, T. A.; Alleman, J.; Keane, J.

    1997-04-01

    This concept paper describes a patented, novel photovoltaic (PV) technology that is capable of achieving near-term commercialization and profitability based upon design features that maximize product performance while minimizing initial and future manufacturing costs. DayStar Technologies plans to exploit these features and introduce a product to the market based upon these differential positions. The technology combines the demonstrated performance and reliability of existing thin-film PV product with a cell and module geometry that cuts material usage by a factor of 5, and enhances performance and manufacturability relative to standard flat-plate designs. The target product introduction price is 1.50/Watt-peak (Wp). This is approximately one-half the cost of the presently available PV product. Additional features include: increased efficiency through low-level concentration, no scribe or grid loss, simple series interconnect, high voltage, light weight, high-throughput manufacturing, large area immediate demonstration, flexibility, modularity.

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

    CERN Document Server

    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.

  4. Hydrogen passivation of polycrystalline Si thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    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.)

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

    OpenAIRE

    Alekhya Reddy, N.; Nikhilbharadwaj, V. V. S.

    2014-01-01

    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.

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

    OpenAIRE

    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...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    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/Cu2ZnSnS4 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

  9. Texture ZnO Thin-Films and their Application as Front Electrode in Solar Cells

    Directory of Open Access Journals (Sweden)

    Yue-Hui Hu

    2010-12-01

    Full Text Available In this paper, three kinds of textured ZnO thin-films (the first kind has the textured structure with both columnar and polygon, the second posses pyramid-like textured structure only, and the third has the textured structure with both crater-like and pyramid-like, were prepared by three kinds of methods, and the application of these ZnO thin-films as a front electrode in solar cell was studied, respectively. In the first method with negative bias voltage and appropriate sputtering parameters, the textured structure with columnar and polygon on the surface of ZnO thin-film are both existence for the sample prepared by direct magnetron sputtering. Using as a front electrode in solar cell, the photoelectric conversion efficiency Eff of 7.00% was obtained. The second method is that by sputtering on the ZnO:Al self-supporting substrate, and the distribution of pyramid-like was gained. Moreover, the higher (8.25% photoelectric conversion efficiency of solar cell was got. The last method is that by acid-etching the as-deposited ZnO thin-film which possesses mainly both columnar and polygon structure, and the textured ZnO thin-film with both crater-like and pyramid-like structure was obtained, and the photoelectric conversion efficiency of solar cell is 7.10% when using it as front electrode. These results show that the textured ZnO thin-film prepared on self-supporting substrate is more suitable for using as a front electrode in amorphous silicon cells.

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

    International Nuclear Information System (INIS)

    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.)

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

    OpenAIRE

    Zhang, Zhenhao

    2013-01-01

    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.

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

    International Nuclear Information System (INIS)

    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

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

    CERN Document Server

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Asymmetric intermediate reflector for tandem micromorph thin film silicon solar cells

    OpenAIRE

    So?derstro?m, T.; Haug, F. -j; Niquille, X.; Terrazzoni, V.; Ballif, C.

    2009-01-01

    The micromorph solar cell (stack of amorphous and microcrystalline cells) concept is the key for achieving high efficiency stabilized thin film silicon solar cells. We introduce a device structure that allows a better control of the light in-coupling into the two subcell components. It is based on an asymmetric intermediate reflector, which increases the effective thickness of the a-Si:H by a factor of more than three. Hence, the a- Si:H thickness reduction dimi...

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    OpenAIRE

    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...

  20. Designing optimized nano textures for thin-film silicon solar cells :

    OpenAIRE

    Ja?ger, K.; Fischer, M.; Swaaij, R. A. C. M. M.; Zeman, M.

    2013-01-01

    Thin-film silicon solar cells (TFSSC), which can be manufactured from abundant materials solely, contain nano-textured interfaces that scatter the incident light. We present an approximate very fast algorithm that allows optimizing the surface morphology of two-dimensional nano-textured interfaces. Optimized nano-textures scatter the light incident on the solar cell stronger leading to a higher short-circuit current density and thus efficiency. Our algorithm combines a recently developed scat...

  1. Single-layer organic–inorganic-hybrid thin-film encapsulation for organic solar cells

    International Nuclear Information System (INIS)

    We demonstrate an organic–inorganic-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 µm 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 organic–inorganic-hybrid thin film is promising for the encapsulation of organic solar cells. (paper)

  2. Porous nanocrystalline TiO2 thin films for dye-sensitized solar cells

    Science.gov (United States)

    Fan, Xiaojuan; Swanson, Claudia; Rogow, David; Tripathi, Akhilesh; Oliver, Scott

    2008-03-01

    We report a rapid and low cost method to fabricate porous TiO2 thin films used as anode electrodes for solid state dye-sensitized solar cells. Polymethylmethacrylate (PMMA) gel was used as template to define a network co-structure with alkali titanium oxide, then spin cast on substrates. After thermally removing polymer, smooth and crack-free large area TiO2 thin films with fine pores were generated. Thin film structures were detected by powder & grazing incident X-ray diffraction. Film thickness can be controlled over a range of tens of nanometers to several microns by precursor viscosity, spin coating speed and coating times. The SEM image shows the highest quality porous TiO2 film derived from a certain concentration of precursor. The above TiO2 thin films were then used to fabricate solid state dye sensitized solar cells. Porphyrine dye and poly(ethylene glycol) electrolyte with I^-/I3^- redox couple were used in the cells. Current-voltage curves were recorded. The open circuit voltage boosts to more than 1.0 V. The reasons for the high open circuit voltage probably will be discussed. Overall photo-electricity conversion efficiency reaches 2.05% under an illumination of one solar unit (AM1.5, 100 mW/cm^2).

  3. Perovskite Solar Cell Using a Two-Dimensional Titania Nanosheet Thin Film as the Compact Layer.

    Science.gov (United States)

    Li, Can; Li, Yahui; Xing, Yujin; Zhang, Zelin; Zhang, Xianfeng; Li, Zhen; Shi, Yantao; Ma, Tingli; Ma, Renzhi; Wang, Kunlin; Wei, Jinquan

    2015-07-22

    The compact layer plays an important role in conducting electrons and blocking holes in perovskite solar cells (PSCs). Here, we use a two-dimensional titania nanosheet (TNS) thin film as the compact layer in CH3NH3PbI3 PSCs. TNS thin films with thicknesses ranging from 8 to 75 nm were prepared by an electrophoretic deposition method from a dilute TNS/tetrabutylammonium hydroxide solution. The TNS thin films contact the fluorine-doped tin oxide grains perfectly. Our results show that a 8-nm-thick TNS film is sufficient for acting as the compact layer. Currently, the PSC with a TNS compact layer has a high efficiency of 10.7% and relatively low hysteresis behavior. PMID:26158908

  4. Improving thin-film crystalline silicon solar cell efficiencies with photonic crystals.

    Science.gov (United States)

    Bermel, Peter; Luo, Chiyan; Zeng, Lirong; Kimerling, Lionel C; Joannopoulos, John D

    2007-12-10

    Most photovoltaic (solar) cells are made from crystalline silicon (c-Si), which has an indirect band gap. This gives rise to weak absorption of one-third of usable solar photons. Therefore, improved light trapping schemes are needed, particularly for c-Si thin film solar cells. Here, a photonic crystal-based light-trapping approach is analyzed and compared to previous approaches. For a solar cell made of a 2 mum thin film of c-Si and a 6 bilayer distributed Bragg reflector (DBR) in the back, power generation can be enhanced by a relative amount of 24.0% by adding a 1D grating, 26.3% by replacing the DBR with a six-period triangular photonic crystal made of air holes in silicon, 31.3% by a DBR plus 2D grating, and 26.5% by replacing it with an eight-period inverse opal photonic crystal. PMID:19550990

  5. Optical Layers for Thin-film Silicon Solar Cells

    OpenAIRE

    Cuony, Peter

    2011-01-01

    In this work we develop and analyze optical layers for use in Micromorph solar cells, a tandem configuration with an amorphous silicon top cell and a microcrystalline silicon bottom cell. The morphology of the front electrode has a decisive role in maximizing the efficiency of a solar cell. To reach a better understanding of the requirements for the front electrode surface, we present a wide range of morphologies that can be obtained with as-grown rou...

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Selective Ablation of Thin Films with Picosecond-Pulsed Lasers for Solar Cells

    Science.gov (United States)

    Ra?iukaitis, G.; Ge?ys, P.; Gedvilas, M.; Regelskis, K.; Voisiat, B.

    2010-10-01

    Functional thin-films are of high importance in modern electronics for flat panel displays, photovoltaics, flexible and organic electronics. Versatile technologies are required for patterning thin-film materials on rigid and flexible substrates. The large-area applications of thin films such as photovoltaics need high speed and simple to use techniques. Ultra-short laser processing with its flexibility is one of the ways to achieve high quality material etching but optimization of the processes is required to meet specific needs of the applications. Lasers with picosecond pulse duration were applied in selective ablation of conducting, semi-conducting and isolating films in the complex multilayered thin-film solar cells based on amorphous Si and CuInxGa(1-x)Se2 (CIGS) deposited on glass and polymer substrates. Modeling of energy transition between the layers and temperature evolution was performed to understand the processes. Selection of the right laser wavelength was important to keep the energy coupling in a well defined volume at the interlayer interface. Ultra-short pulses ensured high energy input rate into absorbing material permitting peeling of the layers with no influence on the remaining material. Use of high repetition rate lasers with picosecond pulse duration offers new possibilities for high quality and efficiency patterning of advanced materials for thin-film electronics.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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

  11. Development of textured back reflector for n-i-p flexible silicon thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Ke; He, Qing; Zhang, Yi; Sun, Yun [Institute of Photo-electronics Thin Film Devices and Technique, Nankai University (China); Zhang, Dexian; Wang, Linshen; Zhao, Jingfang; Cai, Hongkun; Sui, Yanping; Qiao, Zaixiang [Department of Electronic Science and Technology, Nankai University (China)

    2010-05-15

    For silicon thin film solar cells, light trapping strategies, to increase the path length of incoming light, play a decisive role for device performance. In this work, a new way to develop textured back reflectors for n-i-p flexible solar cells is studied. ZnO:Ga films are deposited by DC magnetron sputtering system using two facing Ga-doped ZnO ceramic targets at room temperature. The influence of distance between substrate and plasma on the structure and etching characteristic of ZnO:Ga is investigated. Polyimide/textured ZnO:Ga/Al structure is used as the back reflector, and the morphological and optical analyses indicate that it is suitable to be used in the silicon thin film solar cells. (author)

  12. Development of transparent conductive oxide for thin-film silicon solar cells

    International Nuclear Information System (INIS)

    Gallium-doped zinc oxide (GZO) films were deposited by DC magnetron sputtering using a GZO ceramic target at various substrate temperatures from 298 to 573 K in order to apply the films to amorphous silicon thin film solar cells. A low resistivity (?4.28 x 10-4 ?cm) and a high transmittance (>90%) were obtained from the film deposited at 573 K. From X-ray diffraction, the films had columnar structures oriented along the c-axis, regardless of the substrate temperature. The lattice images and the grains were observed by using a field emission transmission electron microscope. A grain was overlapped by the crystallite of 10-15 nm, and the size of a grain was about 70 nm. Finally, the texturing conditions of the GZO films were optimized as a function of deposition temperature for potential applications to tandem solar cells and single junction amorphous silicon thin film solar cells.

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

    Science.gov (United States)

    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).

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

    Science.gov (United States)

    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

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

    International Nuclear Information System (INIS)

    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)

  16. Integration of solar sail and thin film solar cell using spectrum splitting technology for deep space exploration

    Science.gov (United States)

    Feng, Yudong; Zuo, Huaping; Wang, Zhimin

    It is very important to lighten weight for deep space exploration. Thin film type spacecrafts like solar sails may be the good choice. Due to the favourable photoelectric effect in weak light and light weight, flexible thin film solar sell will also be considered as new generation energy. In order to integrate thin film solar cell into solar sail perfectly, the spectrum splitting technology using optical multilayer film is employed to divide the solar spectrum. The transmissivity of the designed optical film is calculated by a developed computer program. It shows that that the transmissivity is larger than 95% in the range 400-1000nm, and obviously decrease above 400 nm, and below 1000 nm. The result given in this work will provide a new way to realize a low area mass of the solar sail.

  17. Flexible, Thin-Film Solar-Cell Blanket

    Science.gov (United States)

    Stella, Paul M.

    1992-01-01

    Much of available area used to absorb solar energy. Proposed blanket of solar photovoltaic cells mounted on exterior surface of equipment it powers. Readily conforms to irregular shapes. Does not require separate supporting structure and saves space. Not added on to equipment but constitutes an integral part of it. Interconnection wiring deposited on sheet photolithographically or by other suitable masking/fabrication methods. Complete blanket, including cells and interconnections, fabricated as rigid unit directly on, and supported by, nonplanar surface to be covered.

  18. Thin film solar cell inflatable ultraviolet rigidizable deployment hinge

    Science.gov (United States)

    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.

  19. Real time intelligent process control system for thin film solar cell manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    George Atanasoff

    2010-10-29

    This project addresses the problem of lower solar conversion efficiency and waste in the typical solar cell manufacturing process. The work from the proposed development will lead toward developing a system which should be able to increase solar panel conversion efficiency by an additional 12-15% resulting in lower cost panels, increased solar technology adoption, reduced carbon emissions and reduced dependency on foreign oil. All solar cell manufacturing processes today suffer from manufacturing inefficiencies that currently lead to lower product quality and lower conversion efficiency, increased product cost and greater material and energy consumption. This results in slower solar energy adoption and extends the time solar cells will reach grid parity with traditional energy sources. The thin film solar panel manufacturers struggle on a daily basis with the problem of thin film thickness non-uniformity and other parameters variances over the deposited substrates, which significantly degrade their manufacturing yield and quality. Optical monitoring of the thin films during the process of the film deposition is widely perceived as a necessary step towards resolving the non-uniformity and non-homogeneity problem. In order to enable the development of an optical control system for solar cell manufacturing, a new type of low cost optical sensor is needed, able to acquire local information about the panel under deposition and measure its local characteristics, including the light scattering in very close proximity to the surface of the film. This information cannot be obtained by monitoring from outside the deposition chamber (as traditional monitoring systems do) due to the significant signal attenuation and loss of its scattering component before the reflected beam reaches the detector. In addition, it would be too costly to install traditional external in-situ monitoring systems to perform any real-time monitoring over large solar panels, since it would require significant equipment refurbishing needed for installation of multiple separate ellipsometric systems, and development of customized software to control all of them simultaneously. The proposed optical monitoring system comprises AccuStrata’s fiber optics sensors installed inside the thin film deposition equipment, a hardware module of different components (beyond the scope of this project) and our software program with iterative predicting capability able to control material bandgap and surface roughness as films are deposited. Our miniature fiber optics monitoring sensors are installed inside the vacuum chamber compartments in very close proximity where the independent layers are deposited (an option patented by us in 2003). The optical monitoring system measures two of the most important parameters of the photovoltaic thin films during deposition on a moving solar panel - material bandgap and surface roughness. In this program each sensor array consists of two fiber optics sensors monitoring two independent areas of the panel under deposition. Based on the monitored parameters and their change in time and from position to position on the panel, the system is able to provide to the equipment operator immediate information about the thin films as they are deposited. This DoE Supply Chain program is considered the first step towards the development of intelligent optical control system capable of dynamically adjusting the manufacturing process “on-the-fly” in order to achieve better performance. The proposed system will improve the thin film solar cell manufacturing by improving the quality of the individual solar cells and will allow for the manufacturing of more consistent and uniform products resulting in higher solar conversion efficiency and manufacturing yield. It will have a significant impact on the multibillion-dollar thin film solar market. We estimate that the financial impact of these improvements if adopted by only 10% of the industry ($7.7 Billion) would result in about $1.5 Billion in savings by 2015 (at the assumed 20% improvement). This can b

  20. Thin film silicon solar cells in a semi-transparent micro-structured metal substrate configuration

    OpenAIRE

    Denizot, C.; Fay?, S.; Bailat, J.; Jensen, S.; Johansson, A.; Lillemose, M.; Bezzel, E.; Ballif, C.

    2009-01-01

    We present our work on the combination of thin film silicon solar cells and a commercial window shading device (MicroShadeTM, PhotoSolar) into a novel, glass integrated photovoltaic product for building integration. The development of amorphous silicon solar cells (a-Si:H) on the MicroShadeTM substrates was carried out following two simultaneous paths; First the deposition process for a-Si:H solar cells on this new perforated substrate was investigated and modified in order to achieve higher ...

  1. Angular behavior of the absorption limit in thin film silicon solar cells

    CERN Document Server

    Naqavi, Ali; Söderström, Karin; Battaglia, Corsin; Paeder, Vincent; Scharf, Toralf; Herzig, Hans Peter; Ballif, Christophe

    2013-01-01

    We investigate the angular behavior of the upper bound of absorption provided by the guided modes in thin film solar cells. We show that the 4n^2 limit can be potentially exceeded in a wide angular and wavelength range using two-dimensional periodic thin film structures. Two models are used to estimate the absorption enhancement; in the first one, we apply the periodicity condition along the thickness of the thin film structure but in the second one, we consider imperfect confinement of the wave to the device. To extract the guided modes, we use an automatized procedure which is established in this work. Through examples, we show that from the optical point of view, thin film structures have a high potential to be improved by changing their shape. Also, we discuss the nature of different optical resonances which can be potentially used to enhance light trapping in the solar cell. We investigate the two different polarization directions for one-dimensional gratings and we show that the transverse magnetic pola...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Thin film solar cell configuration and fabrication method

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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

  6. Measurements of Raman crystallinity profiles in thin-film microcrystalline silicon solar cells

    International Nuclear Information System (INIS)

    Wedge-polished thin film microcrystalline silicon solar cells are prepared and used for micro-Raman measurements. Thereby, the variations of the Raman crystallinity with depth are accessed easily. Depth resolution limits of the measurement set-up are established and calculations evidencing the role of optical limits are presented. Due to this new technique, Raman crystallinity profiles of two microcrystalline silicon cells give first hints for the optimization of the profile leading to improved electrical performance of such devices. (paper)

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

    OpenAIRE

    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-of...

  8. Advanced Light Management Approaches for Thin-Film Silicon Solar Cells :

    OpenAIRE

    Zeman, M.; Isabella, O.; Jäger, K.; Santbergen, R.; Solntsev, S.; Topic, M.; Krc, J.

    2012-01-01

    Light management is important for improving the performance of thin-film solar cells. Advanced concepts of efficient light scattering and trapping inside the cell structures need to be investigated. An important tool for design and optimisation of the concepts present optical modelling and simulation. In the article a model of light scattering at textured surfaces, which is based on first order Born approximation and the Fraunhofer diffraction, is presented. Another approach presents rigorous...

  9. Microcrystalline/micromorph silicon thin-film solar cells prepared by VHF-GD technique

    OpenAIRE

    Meier, Johannes; Vallat-sauvain, Evelyne; Dubail, S.; Kroll, U.; Dubail, J.; Golay, S.; Feitknecht, Luc; Torres, Pedro; Fay?, Sylvie; Fischer, D.; Shah, Arvind

    2008-01-01

    Hydrogenated microcrystalline silicon prepared at low temperatures by the glow discharge technique is examined here with respect to its role as a new thin-film photovoltaic absorber material. XRD and TEM characterisations reveal that microcrystalline silicon is a semiconductor with a very complex morphology. Microcrystalline p–i–n cells with open-circuit voltages of up to 560–580 mV could be prepared. “Micromorph” tandem solar cells show under outdoor conditions higher short-circuit...

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  12. Advanced characterization techniques for thin film solar cells

    CERN Document Server

    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

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

    International Nuclear Information System (INIS)

    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.

  14. Radiation resistance of thin-film solar cells for space photovoltaic power

    Science.gov (United States)

    Woodyard, James R.; Landis, Geoffrey A.

    1991-01-01

    Copper indium diselenide, cadmium telluride, and amorphous silicon alloy solar cells have achieved noteworthy performance and are currently being studied for space power applications. Cadmium sulfide cells had been the subject of much effort but are no longer considered for space applications. A review is presented of what is known about the radiation degradation of thin film solar cells in space. Experimental cadmium telluride and amorphous silicon alloy cells are reviewed. Damage mechanisms and radiation induced defect generation and passivation in the amorphous silicon alloy cell are discussed in detail due to the greater amount of experimental data available.

  15. TCAD studies of novel nanoplate amorphous silicon alloy thin-film solar cells

    International Nuclear Information System (INIS)

    A novel nanoplate-structured thin-film solar cell was investigated that could solve the conflict between light absorption and carrier transport in a p-type amorphous silicon carbide (a-SiC)/i-type amorphous silicon germanide (a-SiGe)/n-type amorphous silicon (a-Si) thin-film solar cell. This structure has an n-type a-Si nanoplate array on the substrate, a-SiC p-layer, and an a-SiGe i-layer which are sequentially grown along the surface of each n-type a-Si nanoplate. Under illumination by sunlight, light is absorbed along the vertical direction of the nanoplate, while the carrier transport is along the horizontal direction. The nanoplate structure may absorb most of the sunlight and provide a thinner film for the effective transport of photon-generated carriers as compared to the conventional planar structure.

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

    Energy Technology Data Exchange (ETDEWEB)

    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%.

  17. First principles study of Bi dopen CdTe thin film solar cells: electronic and optical properties

    OpenAIRE

    Semino?vski Pe?rez, Yohanna; Palacios Clemente, Pablo; Wahno?n Benarroch, Perla

    2011-01-01

    Nowadays, efficiency improvement of solar cells is one of the most important issues in photovoltaic systems and CdTe is one of the most promising thin film photovoltaic materials we can found. CdTe reported efficiencies in solar energy conversion have been as good as that found in polycrystalline Si thin film cell [1], besides CdTe can be easily produced at industrial scale.

  18. Periodic light coupler gratings in amorphous thin film solar cells

    International Nuclear Information System (INIS)

    Efficient light trapping structures for amorphous hydrogenated silicon (a-Si:H) solar cells have been realized using periodically structured aluminum doped zinc oxide (ZnO:Al) with periods between 390 and 980 nm as a transparent front contact. Atomic force microscopy, optical reflection, and diffraction efficiency measurements were applied to characterize solar cells deposited on such gratings. A simple formula for the threshold wavelength of total internal reflection is derived. Periodic light coupler gratings reduce the reflectance to a value below 10% in the wavelength range of 400 - 800 nm which is comparable to cells with an optimized statistical texture. Diffraction efficiency measurements and theoretical considerations indicate that a combination of transmission and reflection gratings contribute to the observed reduction of the reflectance. [copyright] 2001 American Institute of Physics

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

    Science.gov (United States)

    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 ?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 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.

  20. Admittance spectroscopy of Cu2ZnSnS4 based thin film solar cells

    OpenAIRE

    Fernandes, P. A.; Sartori, A. F.; Salome?, P. M. P.; Malaquias, J.; Cunha, A. F. Da; Grac?a, M. P. F.; Gonza?lez, J. C.

    2012-01-01

    In this report, we propose an AC response equivalent circuit model to describe the admittance measurements of Cu2ZnSnS4 thin film solar cell grown by sulphurization of stacked metallic precursors. This circuit describes the contact resistances, the back contact, and the heterojunction with two trap levels. The study of the back contact resistance allowed the estimation of a back contact barrier of 246 meV. The analysis of the trap series with varying temperature revealed defect...

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

    Czech Academy of Sciences Publication Activity Database

    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 ?R(CZ) GAP108/12/0814 Institutional support: RVO:61388955 Keywords : TiO2 * thin films * dye-sensitized solar cell Subject RIV: CG - Electrochemistry

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

    OpenAIRE

    Gabriel Onno; Kirner Simon; Klick Michael; Stannowski Bernd; Schlatmann Rutger

    2014-01-01

    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 ...

  3. CuInSe2 thin film solar cells synthesised from electrodeposited binary selenide precursors

    OpenAIRE

    Fischer, Johannes

    2012-01-01

    The box must contain a summary in a maximum of 1,700 characters, spaces included. The fabrication of a CuInSe2 thin film solar cell from an electrodeposited precursor stack consisting of indium selenide and copper selenide layers is demonstrated. A best conversion efficiency of 5.5% was achieved, a higher efficiency than previously reported in literature. The thesis focuses on three main parts: (i) electrochemistry of indium selenide: The incorporation of indium in the deposit require...

  4. Integrated photonic structures for light trapping in thin-film Si solar cells

    OpenAIRE

    Sheng, Xing; Johnson, Steven G.; Broderick, Lirong Z.; Michel, Jurgen; Kimerling, Lionel C.

    2012-01-01

    We explore the mechanisms for an efficient light trapping structure for thin-film silicon solar cells. The design combines a distributed Bragg reflector (DBR) and periodic gratings. Using photonic band theories and numerical simulations, we discover that light can be scattered into the DBR by gratings, with an unusual way of light trapping different from metal reflectors and photonic crystals. We further investigate the influence of DBR on generated photocurrent in different device configurat...

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

    Czech Academy of Sciences Publication Activity Database

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

    2014-01-01

    Ro?. 105, ?. 11 (2014), "111106-1"-"111106-4". ISSN 0003-6951 R&D Projects: GA ?R GA14-15357S; GA MŠk(CZ) LM2011026; GA MŠk 7E12029 Grant ostatní: 7FP FAST TRACK(XE) 283501 Institutional support: RVO:68378271 Keywords : light trapping * microcrystalline silicon * thin film solar cell * Raman spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.515, year: 2013

  6. Energy band alignment in chalcogenide thin film solar cells from photoelectron spectroscopy.

    Science.gov (United States)

    Klein, Andreas

    2015-04-10

    Energy band alignment plays an important role in thin film solar cells. This article presents an overview of the energy band alignment in chalcogenide thin film solar cells with a particular focus on the commercially available material systems CdTe and Cu(In,Ga)Se2. Experimental results from two decades of photoelectron spectroscopy experiments are compared with density functional theory calculations taken from literature. It is found that the experimentally determined energy band alignment is in good agreement with theoretical predictions for many interfaces. These alignments, in particular the theoretically predicted alignments, can therefore be considered as the intrinsic or natural alignments for a given material combination. The good agreement between experiment and theory enables a detailed discussion of the interfacial composition of Cu(In,Ga)Se2/CdS interfaces in terms of the contribution of ordered vacancy compounds to the alignment of the energy bands. It is furthermore shown that the most important interfaces in chalcogenide thin film solar cells, those between Cu(In,Ga)Se2 and CdS and between CdS and CdTe are quite insensitive to the processing of the layers. There are plenty of examples where a significant deviation between experimentally-determined band alignment and theoretical predictions are evident. In such cases a variation of band alignment of sometimes more than 1 eV depending on interface preparation can be obtained. This variation can lead to a significant deterioration of device properties. It is suggested that these modifications are related to the presence of high defect concentrations in the materials forming the contact. The particular defect chemistry of chalcogenide semiconductors, which is related to the ionicity of the chemical bond in these materials and which can be beneficial for material and device properties, can therefore cause significant device limitations, as e.g. in the case of the CuInS2 thin film solar cells or for new chalcogenide absorber materials. PMID:25767081

  7. High fidelity transfer of nanometric random textures by UV embossing for thin film solar cells applications

    OpenAIRE

    Escarre? Palou, Jordi; So?derstro?m, Karin; Battaglia, Corsin; Haug, Franz-josef; Ballif, Christophe

    2011-01-01

    We investigate the transfer of random nanostructures commonly used in thin film silicon solar cells onto inexpensive substrates, such as glass or flexible polyethylene sheets. Morphological and optical analyses of masters and replicas show the successful transfer of details with sizes much below 1 ?m. These high-quality replicas are obtained by UV nano-imprinting, avoiding the use of PDMS as intermediate mold which has been identified as being responsible for the lack of resolution fou...

  8. 3D Optical Simulation of Scattering in Thin Film Silicon Solar Cells

    OpenAIRE

    Peters, M.; Battaglia, C.; A. G. Aberle; Luther, J.; Bläsi, B; Glunz, S.

    2011-01-01

    Efficient light trapping is of great importance for thin-film silicon solar cells. Randomly textured TCO or glass substrates provide excellent light trapping and are frequently applied. Optical simulation of such textures is challenging due to a large variety of occurring geometrical features. In this paper we suggest an approach for the 3D optical simulation of scattering structures. This approach is based on a simulation and investigation of the constituting single structure features and su...

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

    Czech Academy of Sciences Publication Activity Database

    Pikna, Peter; Fejfar, Antonín; Ledinský, Martin; Vetushka, Aliaksi; Ko?ka, 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 ?R KAN400100701; GA MŠk LC510 Grant ostatní: FP7(XE) 240826 Institutional research plan: CEZ:AV0Z10100521 Keywords : polycrystalline silicon * thin film solar cells * water vapor passivation Subject RIV: BM - Solid Matter Physics ; Magnetism

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

    OpenAIRE

    Lipovšek, B.; Kr?, J.; Isabella, O.; Zeman, M.; M. Topi?

    2010-01-01

    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 optimi...

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

    OpenAIRE

    Werner, J.H.; Vetter, M; M. Grauvogl; R. M. Hausner; T. J. Rinke; R. B. Bergmann

    1999-01-01

    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 confir...

  12. Performance predictions for monolithic thin-film CdTe/Ge tandem solar cells

    Science.gov (United States)

    Pulfrey, D. L.; Dell, J.; Faraone, L.

    2010-06-01

    Cadmium telluride thin-film solar cells are now commercially available and are being widely deployed in terrestrial, photovoltaic, power plants. However, the price of electricity from such sources would be more competitive with conventionally generated electricity if the cell efficiency could be improved without compromising the generally low-cost nature of the fabrication process. Recognizing that laboratory cells appear to have reached an efficiency limit of about 16.5%, we propose to improve on this by adding a thin-film germanium cell in a monolithic, tandem arrangement. Here we report on simulations of the photovoltaic performance of this structure, and we indicate that an efficiency improvement in excess of 20% may be attainable.

  13. Positron annihilation study on CuInSe2 solar cell thin films

    International Nuclear Information System (INIS)

    Positron annihilation spectroscopy has been used to investigate CuInSe2 solar cell thin films. The films were grown on Mo-coated soda lime glass substrates by the electrochemical deposition processing technique. As-grown samples are found to contain large concentration of vacancy defects. The selenium (Se) atmosphere and sulfur (S) atmosphere annealing of as-grown samples at 800 K can dramatically reduce the number of vacancy defects and the film becomes crystalline. In addition, a defect layer of about 50 nm thickness was observed at the surface of the CuInSe2 thin film. This layer results from the electrochemical deposition method, but the defect concentration in the defect layer can be greatly reduced by annealing in selenium atmosphere. The Doppler broadening line shape parameter correlation plot provided evidence that the positron trapping defect states where in three samples. - Highlights: ? As-grown CuInSe2 thin films contain large concentration of defects. ? A defect layer of about 50 nm exists in the CuInSe2 thin film surface. ? The defect concentration in the defect layer can be greatly reduced.

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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 200°C 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 85°C) was found to be lower than that of the AZO and GZO thin films. The surface texture formation was carried out by wet-che formation was carried out by wet-chemical etching (in a 0.1% HCl solution at 25°C) 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 500°C 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.

  16. Modeling and Design of a Thin-Film CdTe/Ge Tandem Solar Cell

    Science.gov (United States)

    Sharp, James; Pulfrey, David; Umana-Membreno, Gilberto A.; Faraone, Lorenzo; Dell, John M.

    2012-10-01

    Thin-film cadmium telluride (CdTe) solar cells have found widespread application, with current commercially available module efficiencies reaching 14.4% and production costs falling as low as US 0.75/W_p. Despite the proliferation of this technology, there have been comparatively few developments in research circles in recent years. Rather than attempt to further advance the materials science of CdTe solar cells, it is proposed to realize an efficiency improvement over conventional cells by means of a novel tandem structure. Three such structures are examined herein, and results of simulation using Synopsys Sentaurus TCAD are presented.

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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 (22d 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

  19. 3D photonic crystal intermediate reflector for micromorph thin-film tandem solar cell

    Energy Technology Data Exchange (ETDEWEB)

    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.)

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

    Czech Academy of Sciences Publication Activity Database

    Fejfar, Antonín; Klapetek, P.; Zlámal, J.; Vetushka, Aliaksi; Ledinský, Martin; Ko?ka, 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 ?R 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

  1. Cross-sectional electrostatic force microscopy of thin-film solar cells

    International Nuclear Information System (INIS)

    In a recent work, we showed that atomic force microscopy (AFM) is a powerful technique to image cross sections of polycrystalline thin films. In this work, we apply a modification of AFM, namely, electrostatic force microscopy (EFM), to investigate the electronic properties of cleaved II--VI and multijunction thin-film solar cells. We cleave the devices in such a way that they are still working with their nominal photovoltaic efficiencies and can be polarized for the measurements. This allows us to differentiate between surface effects (work function and surface band bending) and bulk device properties. In the case of polycrystalline CdTe/CdS/SnO2/glass solar cells, we find a drop of the EFM signal in the area of the CdTe/CdS interface (±50 nm). This drop varies in amplitude and sign according to the applied external bias and is compatible with an n-CdS/p-CdTe heterojunction model, thereby invalidating the possibility of a deeply buried n-p CdTe homojunction. In the case of a triple-junction GaInP/GaAs/Ge device, we observe a variation of the EFM signal linked to both the material work-function differences and to the voltage bias applied to the cell. We attempt a qualitative explanation of the results and discuss the implications and difficulties of the EFM technique for the study of such thin-film devices

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

    Science.gov (United States)

    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.

  3. The role of front and back electrodes in parasitic absorption in thin-film solar cells

    OpenAIRE

    Boccard Mathieu; Cuony Peter; Hänni Simon; Stuckelberger Michael; Haug Franz-Josef; Meillaud Fanny; Despeisse Matthieu; Ballif Christophe

    2014-01-01

    When it comes to parasitic absorption in thin-film silicon solar cells, most studies focus on one electrode only, most of the time the substrate (in n-i-p configuration) or superstrate (in p-i-n configuration). We investigate here simultaneously the influence of the absorption in both front and back electrodes on the current density of tandem micromorph solar cells in p-i-n configuration. We compare four possible combinations of front and back electrodes with two different doping levels, but ...

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Hole-conductor-free perovskite organic lead iodide heterojunction thin-film solar cells: High efficiency and junction property

    Science.gov (United States)

    Shi, Jiangjian; Dong, Juan; Lv, Songtao; Xu, Yuzhuan; Zhu, Lifeng; Xiao, Junyan; Xu, Xin; Wu, Huijue; Li, Dongmei; Luo, Yanhong; Meng, Qingbo

    2014-02-01

    Efficient hole-conductor-free organic lead iodide thin film solar cells have been fabricated with a sequential deposition method, and a highest efficiency of 10.49% has been achieved. Meanwhile, the ideal current-voltage model for a single heterojunction solar cell is applied to clarify the junction property of the cell. The model confirms that the TiO2/CH3NH3PbI3/Au cell is a typical heterojunction cell and the intrinsic parameters of the cell are comparable to that of the high-efficiency thin-film solar cells.

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

    International Nuclear Information System (INIS)

    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. Chemical synthesis of p-type nanocrystalline copper selenide thin films for heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ambade, Swapnil B. [Department of Chemical Engineering, Vishwakarma Institute of Technology, Pune 411037 (India); Mane, R.S. [Inorganic Nanomaterials Laboratory, Department of Chemistry, Hanyang University, Sungdong-Ku, Haengdang-dong 17, Seoul 133-791 (Korea, Republic of); Kale, S.S. [Inorganic Nanomaterials Laboratory, Department of Chemistry, Hanyang University, Sungdong-Ku, Haengdang-dong 17, Seoul 133-791 (Korea, Republic of); Sonawane, S.H. [Department of Chemical Engineering, Vishwakarma Institute of Technology, Pune 411037 (India); Shaikh, Arif V. [Department of Electronic Science, AKI' s Poona College of Arts, Science and Commerce, Camp, Pune 411 001 (India); Han, Sung-Hwan [Inorganic Nanomaterials Laboratory, Department of Chemistry, Hanyang University, Sungdong-Ku, Haengdang-dong 17, Seoul 133-791 (Korea, Republic of)]. E-mail: shhan@hanyang.ac.kr

    2006-12-15

    Nanocrystalline thin films of copper selenide have been grown on glass and tin doped-indium oxide substrates using chemical method. At ambient temperature, golden films have been synthesized and annealed at 200 deg. C for 1 h and were examined for their structural, surface morphological and optical properties by means of X-ray diffraction (XRD), scanning electron microscopy and UV-vis spectrophotometry techniques, respectively. Cu{sub 2-x}Se phase was confirmed by XRD pattern and spherical grains of 30 {+-} 4 - 40 {+-} 4 nm in size aggregated over about 130 {+-} 10 nm islands were seen by SEM images. Effect of annealing on crystallinity improvement, band edge shift and photoelectrochemical performance (under 80 mW/cm{sup 2} light intensity and in lithium iodide electrolyte) has been studied and reported. Observed p-type electrical conductivity in copper selenide thin films make it a suitable candidate for heterojunction solar cells.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

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

    Science.gov (United States)

    Yoo, Su-Hyun; Butler, Keith T.; Soon, Aloysius; Abbas, Ali; Walls, John M.; Walsh, Aron

    2014-08-01

    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.

  11. CIGS2 Thin-Film Solar Cells on Flexible Foils for Space Power

    Science.gov (United States)

    Dhere, Neelkanth G.; Ghongadi, Shantinath R.; Pandit, Mandar B.; Jahagirdar, Anant H.; Scheiman, David

    2002-10-01

    CuIn(1-x)Ga(x)S2 (CIGS2) thin-film solar cells are of interest for space power applications because of the near optimum bandgap for AM0 solar radiation in space. CIGS2 thin film solar cells on flexible stainless steel (SS) may be able to increase the specific power by an order of magnitude from the current level of 65 Wkg-1. CIGS solar cells are superior to the conventional silicon and gallium arsenide solar cells in the space radiation environment. This paper presents research efforts for the development of CIGS2 thin-film solar cells on 127 micrometers and 20 micrometers thick, bright-annealed flexible SS foil for space power. A large-area, dual-chamber, inline thin film deposition system has been fabricated. The system is expected to provide thickness uniformity of plus or minus 2% over the central 5" width and plus or minus 3% over the central 6" width. During the next phase, facilities for processing larger cells will be acquired for selenization and sulfurization of metallic precursors and for heterojunction CdS layer deposition both on large area. Small area CIGS2 thin film solar cells are being prepared routinely. Cu-rich Cu-Ga/In layers were sputter-deposited on unheated Mo-coated SS foils from CuGa (22%) and In targets. Well-adherent, large-grain Cu-rich CIGS2 films were obtained by sulfurization in a Ar: H2S 1:0.04 mixture and argon flow rate of 650 sccm, at the maximum temperature of 475 C for 60 minutes with intermediate 30 minutes annealing step at 120 C. Samples were annealed at 500 C for 10 minutes without H2S gas flow. The intermediate 30 minutes annealing step at 120 C was changed to 135 C. p-type CIGS2 thin films were obtained by etching the Cu-rich layer segregated at the surface using dilute KCN solution. Solar cells were completed by deposition of CdS heterojunction partner layer by chemical bath deposition, transparent-conducting ZnO/ZnO: Al window bilayer by RF sputtering, and vacuum deposition of Ni/Al contact fingers through metal mask. PV parameters of a CIGS2 solar cell on 127 micrometers thick SS flexible foil measured under AM 0 conditions at NASA GRC were: Voc = 802.9 mV, Jsc = 25.07 mA per square centimeters, FF = 60.06%, and efficiency 0 = 8.84%. For this cell, AM 1.5 PV parameters measured at NREL were: Voc = 788 mV, Jsc = 19.78 mA per square centimeter, FF = 59.44%, efficiency 0 = 9.26%. Quantum efficiency curve showed a sharp QE cutoff equivalent to CIGS2 bandgap of approximately 1.50 eV, fairly close to the optimum value for efficient AM0 PV conversion in the space.

  12. CIGS2 Thin-Film Solar Cells on Flexible Foils for Space Power

    Science.gov (United States)

    Dhere, Neelkanth G.; Ghongadi, Shantinath R.; Pandit, Mandar B.; Jahagirdar, Anant H.; Scheiman, David

    2002-01-01

    CuIn(1-x)Ga(x)S2 (CIGS2) thin-film solar cells are of interest for space power applications because of the near optimum bandgap for AM0 solar radiation in space. CIGS2 thin film solar cells on flexible stainless steel (SS) may be able to increase the specific power by an order of magnitude from the current level of 65 Wkg(sup -1). CIGS solar cells are superior to the conventional silicon and gallium arsenide solar cells in the space radiation environment. This paper presents research efforts for the development of CIGS2 thin-film solar cells on 127 micrometers and 20 micrometers thick, bright-annealed flexible SS foil for space power. A large-area, dual-chamber, inline thin film deposition system has been fabricated. The system is expected to provide thickness uniformity of plus or minus 2% over the central 5" width and plus or minus 3% over the central 6" width. During the next phase, facilities for processing larger cells will be acquired for selenization and sulfurization of metallic precursors and for heterojunction CdS layer deposition both on large area. Small area CIGS2 thin film solar cells are being prepared routinely. Cu-rich Cu-Ga/In layers were sputter-deposited on unheated Mo-coated SS foils from CuGa (22%) and In targets. Well-adherent, large-grain Cu-rich CIGS2 films were obtained by sulfurization in a Ar: H2S 1:0.04 mixture and argon flow rate of 650 sccm, at the maximum temperature of 475 C for 60 minutes with intermediate 30 minutes annealing step at 120 C. Samples were annealed at 500 C for 10 minutes without H2S gas flow. The intermediate 30 minutes annealing step at 120 C was changed to 135 C. p-type CIGS2 thin films were obtained by etching the Cu-rich layer segregated at the surface using dilute KCN solution. Solar cells were completed by deposition of CdS heterojunction partner layer by chemical bath deposition, transparent-conducting ZnO/ZnO: Al window bilayer by RF sputtering, and vacuum deposition of Ni/Al contact fingers through metal mask. PV parameters of a CIGS2 solar cell on 127 micrometers thick SS flexible foil measured under AM 0 conditions at NASA GRC were: V(sub oc) = 802.9 mV, J(sub sc) = 25.07 mA per square centimeters, FF = 60.06%, and efficiency 0 = 8.84%. For this cell, AM 1.5 PV parameters measured at NREL were: V(sub oc) = 788 mV, J(sub sc) = 19.78 mA per square centimeter, FF = 59.44%, efficiency 0 = 9.26%. Quantum efficiency curve showed a sharp QE cutoff equivalent to CIGS2 bandgap of approximately 1.50 eV, fairly close to the optimum value for efficient AM0 PV conversion in the space.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Czech Academy of Sciences Publication Activity Database

    Van??ek, Milan; Poruba, Aleš; Remeš, Zden?k; 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 Grant ostatní: 7th FP EU N2P(XE) CP-IP 214134-2; 6FP EU ATHLET(XE) 019670 (SES6) Institutional research plan: CEZ:AV0Z10100521 Keywords : thin film silicon solar cells * amorphous silicon * nanostructure * high stable efficiency Subject RIV: BM - Solid Matter Physics ; Magnetism

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

    Czech Academy of Sciences Publication Activity Database

    Pikna, Peter; Fejfar, Antonín; Pí?, Vlastimil; Müller, Martin; Ledinský, Martin; Vetushka, Aliaksi; Ko?ka, 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 Grant ostatní: 7FP EU PolySiMode(XE) 240826 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

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

    International Nuclear Information System (INIS)

    This investigation elucidates the properties of indium-tin oxide (ITO) thin films used as antireflection front electrodes in ?c-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 ?c-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.

  17. Low-cost, deterministic quasi-periodic photonic structures for light trapping in thin film silicon solar cells

    OpenAIRE

    Sheng, Xing; Liu, Jifeng; Michel, Jurgen; Agarwal, Anuradha Murthy; Kimerling, Lionel C.

    2009-01-01

    Light trapping has been an important issue for thin film silicon solar cells because of the low absorption coefficient in the near infrared range. In this paper, we present a photonic structure which combines anodic aluminum oxide (AAO) and a distributed Bragg reflector (DBR) in the backside of thin film silicon. Simulation results show that this quasi-periodic AAO structure has a stronger light trapping effect than perfectly periodic diffractive gratings. As a proof of concept, we incorporat...

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

    Science.gov (United States)

    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-µm-thick solar cells with SiN (120 nm)/Si CNCG and 2-µm-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.

  19. Photonic and plasmonic structures for enhancing efficiency of thin film silicon solar cells

    Science.gov (United States)

    Pattnaik, Sambit

    Crystalline silicon solar cells use high cost processing techniques as well as thick materials that are ˜ 200µm thick to convert solar energy into electricity. From a cost viewpoint, it is highly advantageous to use thin film solar cells which are generally made in the range of 0.1-3µm in thickness. Due to this low thickness, the quantity of material is greatly reduced and so is the number and complexity of steps involved to complete a device, thereby allowing a continuous processing capability improving the throughput and hence greatly decreasing the cost. This also leads to faster payback time for the end user of the photovoltaic panel. In addition, due to the low thickness and the possibility of deposition on flexible foils, the photovoltaic (PV) modules can be flexible. Such flexible PV modules are well suited for building-integrated applications and for portable, foldable, PV power products. For economical applications of solar cells, high efficiency is an important consideration. Since Si is an indirect bandgap material, a thin film of Si needs efficient light trapping to achieve high optical absorption. The previous work in this field has been mostly based on randomly textured back reflectors. In this work, we have used a novel approach, a periodic photonic and plasmonic structure, to optimize current density of the devices by absorbing longer wavelengths without hampering other properties. The two dimensional diffraction effect generated by a periodic structure with the plasmonic light concentration achieved by silver cones to efficiently propagate light in the plane at the back surface of a solar cell, achieves a significant increase in optical absorption. Using such structures, we achieved a 50%+ increase in short circuit current in a nano-crystalline (nc-Si) solar cell relative to stainless steel. In addition to nc-Si solar cells on stainless steel, we have also used the periodic photonic structure to enhance optical absorption in amorphous cells and tandem junction amorphous/nano-crystalline cells. These structures have been fabricated on flexible plastic substrates. We will describe the use of periodic structures to achieve increased light absorption and enhanced photocurrents in thin film solar cells, and also compare them systematically with other textured substrates. We discuss the various technological aspects and obstacles faced before successful fabrication of such structure, and during the fabrication of solar cells on these structures. The ideas of periodic texturing and random texturing will be compared and an implementation of them together will be discussed.

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

    OpenAIRE

    Per I. Widenborg; Aberle, Armin G.

    2007-01-01

    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 metho...

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

    International Nuclear Information System (INIS)

    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 applicationB 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.

  2. Physical vapor deposition of CdTe thin films at low temperature for solar cell applications

    International Nuclear Information System (INIS)

    Cadmium telluride is successfully utilized as an absorber material for thin film solar cells. Industrial production makes use of high substrate temperatures for the deposition of CdTe absorber layers. However, in order to exploit flexible substrates and to simplify the manufacturing process, lower deposition temperatures are beneficial. Based on the phase diagram of CdTe, predictions on the stoichiometry of CdTe thin films grown at low substrate temperatures are made in this work. These predictions were verified experimentally using additional sources of Cd and Te during the deposition of the CdTe thin films at different substrate temperatures. The deposited layers were analyzed with energy-dispersive X-ray spectroscopy. In case of CdTe layers which were deposited at substrate temperatures lower than 200 C without usage of additional sources we found a non-stoichiometric growth of the CdTe layers. The application of the additional sources leads to a stoichiometric growth for substrate temperatures down to 100 C which is a significant reduction of the substrate temperature during deposition.

  3. Characterization of Optical Properties a-Si:H:B Thin Film For Solar Cell Material

    International Nuclear Information System (INIS)

    The a-Si:H:B thin films were deposited on the glass substrate using plasma DC sputtering technique. The deposition has been done with the following process parameters: the deposition time, gas pressure and substrate temperature with the aim to obtain the optical properties of a-Si:H:B thin films suitable for solar cell material. Variations of deposition time were 0.5 to 2-hour, gas pressure 1.1 to 1.4 x 10-1 Torr and substrate temperature 150 to 300 oC, while the flow rate of the reactive hydrogen was kept constant at 4-sccm. The targets of silicon material were mixed with boron for concentration at (0.1; 0.3; 0.5; 0.7 %). From the optical analysis using UV-Vis spectrophotometer, it was obtained that the maximum optical transmittance of a-Si:H:B thin film at 700 nm wavelength is 47 %. At this conditions, the absorption coefficient is 3.49 x 104 m-1 and the band gap energy of the a-Si:H:B is 1.77 eV. (author)

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

    Science.gov (United States)

    Hilali, Mohamed M.; Yang, Shuqiang; Miller, Mike; Xu, Frank; Banerjee, Sanjay; Sreenivasan, S. V.

    2012-10-01

    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.

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

    International Nuclear Information System (INIS)

    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-VOC values with decrease in FWHM of the TO Raman phonon of crystalline silicon. ? Solar cells were fabricated for I–V-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-VOC measurements and Raman spectroscopy. 1 cm2 cells were prepared for a selection of samples and characterized by I–V-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

  6. Shrinking and growing: grain boundary density reduction for efficient polysilicon thin-film solar cells.

    Science.gov (United States)

    Kim, Dong Rip; Lee, Chi Hwan; Weisse, Jeffrey M; Cho, In Sun; Zheng, Xiaolin

    2012-12-12

    Polycrystalline Si (poly-Si) thin-film, due to its low Si consumption, low substrate cost, and good stability, is an attractive candidate for cost-effective solar cells, but the as-deposited poly-Si typically has a columnar structure with grain boundaries in between, severely limiting the efficiency of the poly-Si. Here, we report a micropillar poly-Si solar cell that utilizes the columnar structure of the as-deposited poly-Si grains. We first formed submicrometer diameter poly-Si pillars, smaller than the initial grain sizes, and used these pillars as the seeds for the subsequent epitaxial growth of Si, which effectively reduces grain boundary density in the final poly-Si crystal. In addition, the vertically aligned micropillar arrays form radial p-n junctions that further mitigate the grain boundary recombination losses by improving the light absorption and charge-carrier collection efficiencies. Consequently, the maximum efficiency of micropillar poly-Si thin-film solar cells is 6.4%, that is, ?1.5 times higher than that of the planar cells. PMID:23167740

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

    International Nuclear Information System (INIS)

    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.

  8. Efficiency limitations of thermally evaporated thin-film SnS solar cells

    International Nuclear Information System (INIS)

    Thin-film solar cells with SnS as absorber material were prepared by thermal evaporation of SnS. The cells were built in a superstrate configuration using Al?:?ZnO coated glass as front contact with an intrinsic ZnO buffer layer and/or CdS window layer and a gold back contact. The IV-characteristics and external quantum efficiency of the devices were determined. The best CdS/SnS solar cell showed a conversion efficiency of 1.6%, a short circuit current density of 19 mA cm?2 and an open circuit voltage of 217 mV. Moreover, band alignments at the interfaces AZO/SnS, CdS/SnS and SnS/Au were determined with in situ x-ray photoelectron spectroscopy to correlate the open circuit voltage limitations of the investigated solar cell device structures. (paper)

  9. Absorbing photonic crystals for mono-crystalline silicon thin film solar cells

    Science.gov (United States)

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

    2012-06-01

    In this paper, we present the integration of an absorbing photonic crystal within a monocrystalline silicon thin film solar cell stack. Optical simulations performed on a complete solar cell revealed that patterning the epitaxial monocrystalline silicon active layer as a 1D and 2D photonic crystal enabled to increase its integrated absorption by 38%rel and 50%rel in the whole 300-1100 nm range, compared to a similar but unpatterned stack. In order to fabricate such promising cells, a specific fabrication process based on holographic lithography, inductively coupled plasma etching and reactive ion etching has been developed and implemented to obtain such photonic crystal patterned solar cells. Optical measurements performed on the patterned stacks highlight the significant absorption enhancement, as expected by simulation. A more advanced structuration combining a front and a rear 1D binary photonic patterning with different periods is designed, enabling a 60%abs larger absorption in silicon.

  10. Engineering polymer-fullerene thin films and solar cells with external fields

    Science.gov (United States)

    Cabral, Joao

    2014-03-01

    Trace amounts of nanoparticles, including fullerenes, can impart stability to thin polymer films against dewetting by the combined effects of pinning the contact lines of dewetting holes and by effectively altering the polymer-substrate interaction. Polymer nanocomposite (meta)stable thin films can yield well-defined morphologies from uniform to spinodal-like, via spontaneous polymer-nanoparticle phase separation and crystallization. Confinement breaks the structural isotropy and generally causes (partial) segregation of components orthogonally to the film surface. Surface energy patterning can thus modulate composition and morphology, both in plane and normal to the surface. Further, UV-visible, and even background, light exposure, in both solutions and melts, is shown to tune the solution stucture and morphology of dewetting and phase separating polymer-fullerene thin films. Neutron reflectivity allows us to locate the various constituents within the film. We find a coupling of fullerene photo-sensitivity and both self-assembly processes which results in controlled pattern formation, and we illustrate the potential with a model polymer-fullerene circuit pattern. We then translate this approach into the directed assembly of energy harvesting bulk heterojunctions thin films. Indeed, a key challenge to the commercialization of organic solar cells remains the achievement of morphological stability, particularly under thermal stress conditions. The directed assembly a blend polymer:PC60BM solar cells via a simple light processing step results in a 10-100 fold increase in device thermal stability and, under certain conditions, enhanced device performance. The enhanced stability is linked to the light-induced oligomerisation of PC60BM that effectively hinders diffusion and crystallization in blends. This effect appears to be general and promises to be an effective and cost-effective strategy to optimize fullerene-based solar cell performance.

  11. Thin-film AlGaAs-GaAs solar cells for the conversion of concentrated solar radiation

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-10-01

    The objective of the study is to investigate the possibility of using thin-film solar cells separated from the substrate for the conversion of concentrated solar radiation. In the thin-film AlGaAs-GaAs solar cells reported here, the p-region is led out to the back face of the cell by Zn diffusion through four radial grooves etched in the n-base. The mechanical strength of the 10-micron structures is achieved by bonding them to a glass plate with an epoxy adhesive before separating them from the substrate. It is shown that, in such a structure, the shading factor can be reduced to a minimum since it does not depend on the area of the p-contact and is determined solely by the area of the etched grooves in the thin (7 microns) GaAs n-layer.

  12. Laser-Induced Indium-Diffusion into Cadmium Sulfide Thin Film for Solar Cell Applications

    International Nuclear Information System (INIS)

    Laser-induced diffusion is employed to dope indium (In) into sputtering-deposited cadmium sulfide (CdS) thin films. The increased optical band gap energy from 2.52 to 2.60 eV with maintenance of high optical transmittance about 60 nm in the 200-nm-thick films, the enhanced mobility over 42.5 cm2/V·s, and the decreased resistivity to 1.42 × 10?3 ?·cm are successfully obtained to be advantageous for a window layer in solar cells

  13. Low temperature thin film silicon solar cells prepared by hot-wire chemical vapor deposition

    OpenAIRE

    Adachi, Michael M.

    2007-01-01

    Thin film amorphous silicon (a-Si) is a low cost alternative to crystalline silicon wafers used in solar cells. a-Si is advantageous in that it can be deposited onto low cost substrates such as glass or flexible polymers, is scalable to large areas, and uses low processing temperatures (< 250°C). The main drawback is that a-Si degrades upon exposure to light. Nanocrystalline silicon (nc-Si:H), on the other hand, deposited in the same method as a-Si but with added hydrogen gas, is stable a...

  14. Unlinking absorption and haze in thin film silicon solar cells front electrodes

    OpenAIRE

    Boccard, Mathieu; Cuony, Peter; Battaglia, Corsin; Despeisse, Matthieu; Ballif, Christophe

    2010-01-01

    We study the respective influence of haze and free carrier absorption (FCA) of transparent front electrodes on the photogenerated current of micromorph thin film silicon solar cells. To decouple the haze and FCA we develop bi-layer front electrodes: a flat indium tin oxide layer assures conduction and allows us to tune FCA while the haze is adjusted by varying the thickness of a highly transparent rough ZnO layer. We show how a minimum amount of FCA leads only to a few percents absorption for...

  15. Effects of defects in semiconductors on reproducibility and performance of thin-film photovoltaic solar cells

    International Nuclear Information System (INIS)

    Thin-film solar cells based on GaAs/AlxGa(1?x)As showing open circuit voltages of (1100–1170) mV and fill factors of (0.80–0.87) have been exposed to external electrical stresses, and current–voltage characteristics were monitored in order to study the effects of defects present in the device structure. It has been found that peculiar kinks, sudden jumps and various deformations occur in current–voltage curves which could be caused when the Fermi level moves position at the device interface. These changes occur when there is a group of defect levels and the Fermi level is forced to move across these levels. The reproducibility and performance of solar cells heavily depend on the properties of these defect structures, and external forces such as electrical stresses, illumination and temperature variations cause changes in the measured current–voltage characteristics. The observed variations during this work together with examples from the literature are presented and discussed in this paper. It is concluded that the control of these defects present in device structures is crucial in developing stable, durable and high-efficiency thin-film solar cells

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

    Science.gov (United States)

    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.

  17. Method of making a thin film cadmium telluride solar cell

    International Nuclear Information System (INIS)

    A method for making a photovoltaic cell is described comprising the steps of: (a) depositing a transparent or semi-transparent conductive window layer onto a substrate; (b) depositing a layer of cadmium telluride including phosphorus onto the window layer; (c) depositing a layer of lead telluride onto the layer of cadmium telluride; and (d) depositing a metallic electrode onto the lead telluride layer

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

    Science.gov (United States)

    Li, Da; Wittmann, Stephan; Kunz, Thomas; Ahmad, Taimoor; Gawehns, Nidia; Hessmann, Maik T.; Ebser, Jan; Terheiden, Barbara; Auer, Richard; Brabec, Christoph J.

    2015-05-01

    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 ?m 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.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  1. Asymmetric intermediate reflector for tandem micromorph thin film silicon solar cells

    Science.gov (United States)

    Söderström, T.; Haug, F.-J.; Niquille, X.; Terrazzoni, V.; Ballif, C.

    2009-02-01

    The micromorph solar cell (stack of amorphous and microcrystalline cells) concept is the key for achieving high efficiency stabilized thin film silicon solar cells. We introduce a device structure that allows a better control of the light in-coupling into the two subcell components. It is based on an asymmetric intermediate reflector, which increases the effective thickness of the a-Si:H by a factor of more than three. Hence, the a-Si:H thickness reduction diminishes the light induced degradation, and micromorph tandem cells with 11.2% initial and 9.8% stabilized efficiencies (1000 h, 50 °C, and 100 mW/cm2) are made on plastic substrates with Tg<180 °C.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    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 (?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 ?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%.

  4. Generation of electrical defects in ion beam assisted deposition of Cu(In,Ga)Se2 thin film solar cells

    International Nuclear Information System (INIS)

    Thin films of Cu(In,Ga)Se2 (CIGS) absorber layers for thin film solar cells have been manufactured on polyimide foil in a low temperature, ion beam assisted co-evaporation process. In the present work a set of CIGS thin films was produced with varying selenium ion energy. Solar cell devices have been manufactured from the films and characterized via admittance spectroscopy and capacitance-voltage profiling to determine the influence of the selenium ion energy on the electric parameters of the solar cells. It is shown that the impact of energetic selenium ions in the CIGS deposition process leads to a change in the activation energy and defect density and also in the spatial distribution of electrically active defects. For the interpretation of the results two defect models are taken into account.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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%.

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

    International Nuclear Information System (INIS)

    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 lfate). 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.

  9. The role of front and back electrodes in parasitic absorption in thin-film solar cells

    Science.gov (United States)

    Boccard, Mathieu; Cuony, Peter; Hänni, Simon; Stuckelberger, Michael; Haug, Franz-Josef; Meillaud, Fanny; Despeisse, Matthieu; Ballif, Christophe

    2014-07-01

    When it comes to parasitic absorption in thin-film silicon solar cells, most studies focus on one electrode only, most of the time the substrate (in n-i-p configuration) or superstrate (in p-i-n configuration). We investigate here simultaneously the influence of the absorption in both front and back electrodes on the current density of tandem micromorph solar cells in p-i-n configuration. We compare four possible combinations of front and back electrodes with two different doping levels, but identical sheet resistance and identical light-scattering properties. In the infrared part of the spectrum, parasitic absorption in the front or back electrode is shown to have a similar effect on the current generation in the cell, which is confirmed by modeling. By combining highly transparent front and back ZnO electrodes and high-quality silicon layers, a micromorph device with a stabilized efficiency of 11.75% is obtained.

  10. The role of front and back electrodes in parasitic absorption in thin-film solar cells

    Directory of Open Access Journals (Sweden)

    Boccard Mathieu

    2014-07-01

    Full Text Available When it comes to parasitic absorption in thin-film silicon solar cells, most studies focus on one electrode only, most of the time the substrate (in n-i-p configuration or superstrate (in p-i-n configuration. We investigate here simultaneously the influence of the absorption in both front and back electrodes on the current density of tandem micromorph solar cells in p-i-n configuration. We compare four possible combinations of front and back electrodes with two different doping levels, but identical sheet resistance and identical light-scattering properties. In the infrared part of the spectrum, parasitic absorption in the front or back electrode is shown to have a similar effect on the current generation in the cell, which is confirmed by modeling. By combining highly transparent front and back ZnO electrodes and high-quality silicon layers, a micromorph device with a stabilized efficiency of 11.75% is obtained.

  11. Exploring the possibility of semiconducting BaSi2 for thin-film solar cell applications

    Science.gov (United States)

    Suemasu, Takashi

    2015-07-01

    Semiconducting BaSi2 has attractive features for thin-film solar cell applications because both a large absorption coefficient and a long minority-carrier diffusion length can be utilized. In this article, we explore the possibility of semiconducting BaSi2 films for thin-film solar cell applications. Recent experimental results on the optical absorption coefficient, minority-carrier diffusion length, and minority-carrier lifetime in undoped n-BaSi2 films are presented. After that, the photoresponse spectra are calculated for a BaSi2 p+n abrupt homojunction diode based on the one-dimensional carrier continuity equation using previously reported experimental values. The individual contributions of the three layers, that is, the neutral p+-type layer, the depletion region, and the neutral n-type layer, to the total photoresponse are discussed. The photoresponse depends on parameters such as layer thickness, minority-carrier diffusion length, and surface recombination velocity. We further estimate the photocurrent density and the open-circuit voltage under AM 1.5 illumination.

  12. A fast deposition-crystallization procedure for highly efficient lead iodide perovskite thin-film solar cells.

    Science.gov (United States)

    Xiao, Manda; Huang, Fuzhi; Huang, Wenchao; Dkhissi, Yasmina; Zhu, Ye; Etheridge, Joanne; Gray-Weale, Angus; Bach, Udo; Cheng, Yi-Bing; Spiccia, Leone

    2014-09-01

    Thin-film photovoltaics based on alkylammonium lead iodide perovskite light absorbers have recently emerged as a promising low-cost solar energy harvesting technology. To date, the perovskite layer in these efficient solar cells has generally been fabricated by either vapor deposition or a two-step sequential deposition process. We report that flat, uniform thin films of this material can be deposited by a one-step, solvent-induced, fast crystallization method involving spin-coating of a DMF solution of CH3NH3PbI3 followed immediately by exposure to chlorobenzene to induce crystallization. Analysis of the devices and films revealed that the perovskite films consist of large crystalline grains with sizes up to microns. Planar heterojunction solar cells constructed with these solution-processed thin films yielded an average power conversion efficiency of 13.9±0.7% and a steady state efficiency of 13% under standard AM 1.5 conditions. PMID:25047967

  13. Development of high band gap protocrystalline material for p-i-n thin film silicon solar cells

    OpenAIRE

    Maurizio, Fabio

    2012-01-01

    High band gap thin film silicon solar cells are of high interest for the use as top cell in triple junctions solar cells. Protocrystalline silicon, in the transition phase between amorphous and microcrystalline silicon, is such a high band gap material. During this project, protocrystalline intrinsic layers have been developed and optimized in p-i-n single junction solar cells by plasma-enhanced chemical vapour deposition (PECVD) in a new multi-chamber deposition system. In the first series, ...

  14. Two-dimensional high efficiency thin-film silicon solar cells with a lateral light trapping architecture

    OpenAIRE

    Fang, Jia; Liu, Bofei; Zhao, Ying; Zhang, Xiaodan

    2014-01-01

    Introducing light trapping structures into thin-film solar cells has the potential to enhance their solar energy harvesting as well as the performance of the cells; however, current strategies have been focused mainly on harvesting photons without considering the light re-escaping from cells in two-dimensional scales. The lateral out-coupled solar energy loss from the marginal areas of cells has reduced the electrical yield indeed. We therefore herein propose a lateral light trapping structur...

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

    CERN Document Server

    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...

  16. In situ silicon oxide based intermediate reflector for thin-film silicon micromorph solar cells

    Science.gov (United States)

    Buehlmann, P.; Bailat, J.; Dominé, D.; Billet, A.; Meillaud, F.; Feltrin, A.; Ballif, C.

    2007-10-01

    We show that SiO-based intermediate reflectors (SOIRs) can be fabricated in the same reactor and with the same process gases as used for thin-film silicon solar cells. By varying input gas ratios, SOIR layers with a wide range of optical and electrical properties are obtained. The influence of the SOIR thickness in the micromorph cell is studied and current gain and losses are discussed. Initial micromorph cell efficiency of 12.2% (Voc=1.40V, fill factor=71.9%, and Jsc=12.1mA/cm2) is achieved with top cell, SOIR, and bottom cell thicknesses of 270, 95, and 1800nm, respectively.

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

    Science.gov (United States)

    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

  18. Electron-reflector strategy for cadmium telluride thin-film solar cells

    Science.gov (United States)

    Hsiao, Kuo-Jui

    The CdTe thin-film solar cell has a large absorption coefficient and high theoretical efficiency. Moreover, large-area photovoltaic panels can be economically fabricated. These features potentially make the CdTe thin-film solar cell the leading alternative energy source. However, the record CdTe efficiency (16.5%) is much less than its theoretical maximum efficiency (29%), primarily because the open-circuit voltage (0.845 V) is well below what is expected for its band gap (1.5 eV). The incorporation of an electron reflector is a strategy to improve the open-circuit voltage of solar cells, and thus a strong possibility to improve the efficiency of CdTe thin-film solar cells. An electron reflector is a conduction-band energy barrier at the back surface of the solar cell, which can reduce the recombination due to the electron flow to the back surface. Different methods to create an electron reflector are explained in the thesis: (1) expanded band gap, either an expanded-band-gap layer or a bulk-band-gap reduction, and (2) alteration to the band bending through a reversed back barrier or a heavily-doped back surface. Investigation shows that the expanded-band-gap layer is the most efficient and practical mechanism for an electron reflector, and the combination of any two mechanisms does not yield additional improvement. To have the optimal effect from the electron-reflector strategy, reasonable CdTe lifetime (1 ns or above) and full depletion of the CdTe layer are required to ensure high carrier collection. Furthermore, a good-quality reflector interface between the p-type CdTe layer and the electron-reflector layer is essential. Preliminary experimental evidence has shown that CdTe cells with a ZnTe back layer do have a slightly higher open-circuit voltage. An electron reflector should be particularly beneficial for thin (less than 2 microm) CdTe cells which have a fully-depleted CdTe absorber layer. Thin CdTe cells can also benefit from the optical reflection at the back surface. To investigate the possibility of still higher efficiency, both electron and optical reflection were numerically applied to the CdTe record-cell baseline model. However, there is little improvement for CdTe thicknesses greater than 2 microm. To have the optimal effect from combined electron and optical reflection, cells approximately one micron thick are required. Even without the improvement to the current quality of CdTe, cell efficiency above 19% should be achievable with a 0.2-eV electron reflector. Moreover, efficiency above 20% should be possible if one can also achieve large optical back reflection. At the same time, competitive CdTe cell performance at a thickness as thin as 0.4 um should be possible. This thesis gives a comprehensive numerical investigation of the electron-reflector strategy for CdTe thin-film solar cells.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Designing optimized nano textures for thin-film silicon solar cells.

    Science.gov (United States)

    Jäger, Klaus; Fischer, Marinus; van Swaaij, René A C M M; Zeman, Miro

    2013-07-01

    Thin-film silicon solar cells (TFSSC), which can be manufactured from abundant materials solely, contain nano-textured interfaces that scatter the incident light. We present an approximate very fast algorithm that allows optimizing the surface morphology of two-dimensional nano-textured interfaces. Optimized nano-textures scatter the light incident on the solar cell stronger leading to a higher short-circuit current density and thus efficiency. Our algorithm combines a recently developed scattering model based on the scalar scattering theory, the Perlin-noise algorithm to generate the nano textures and the simulated annealing algorithm as optimization tool. The results presented in this letter allow to push the efficiency of TFSSC towards their theoretical limit. PMID:24104492

  1. Possibility of Si-based new material for thin-film solar cell applications

    Science.gov (United States)

    Suemasu, T.

    2015-04-01

    We grow BaSi2 epitaxial films on Si(111) substrates by molecular beam epitaxy, and investigate their optical properties such as optical absorption coefficients, minority-carrier diffusion length, and minority-carrier lifetime. These are key parameters which determine the solar cell performance. The band gap of BaSi2 is measured to be approximately 1.3 eV. The absorption coefficient reaches approximately 3×104 cm?1 at 1.5 eV. The minority-carrier diffusion length and minority-carrier lifetime are found to be about 10 ?m and 8 ?s, respectively. These values are sufficiently large for thin-film solar cell applications. Internal photoresponse spectra are deduced from data obtained experimentally.

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

    International Nuclear Information System (INIS)

    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)

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

    CERN Document Server

    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.

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

    International Nuclear Information System (INIS)

    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

  5. CdS-photodoping in quantum efficiency spectra of chalcopyrite thin film solar cells

    International Nuclear Information System (INIS)

    Understanding the electronic properties of the CdS buffer layer typically employed in chalcopyrite thin film solar cells is a key challenge in the pursuit of high device performance. Photodoping of the CdS layer appears to alter the conduction band offset at the CdS/absorber interface by more than 100meV and causes substantial changes in the spectral shape of the external quantum efficiency under forward voltage bias. This contribution examines the nature of CdS-photodoping by means of quantum efficiency measurements for varied temperatures, photon flux densities and excitation frequencies. Rapid photodoping is linked to hole traps inside the CdS buffer similar to those believed to be responsible for cross-over in current-voltage-measurements. The results emphasize the strong influence of CdS-photodoping on chalcopyrite solar cell performance and grant insight into its dynamic nature.

  6. Enhancing light trapping properties of thin film solar cells by plasmonic effect of silver nanoparticles.

    Science.gov (United States)

    Jung, Junhee; Ha, Kyungyeon; Cho, Jaehyun; Ahn, Shihyun; Park, Hyeongsik; Hussain, Shahzada Qamar; Choi, Mansoo; Yi, Junsin

    2013-12-01

    The preparation of thin film silicon solar cells containing Ag nanoparticles is reported in this article. Ag nanoparticles were deposited on fluorine doped tin oxide coated glass substrates by the evaporation and condensation method. a-Si:H solar cells were deposited on these substrates by cluster type plasma enhanced chemical vapor deposition. We discuss the double textured surface effect with respect to both the surface morphology of the substrate and the plasmonic effect of the Ag nanoparticles. Ag nanoparticles of various sizes from 10 to 100 nm were deposited. The haze values of the Ag embedded samples increased with increasing particle size whereas the optical transmittance decreased at the same conditions. The solar cell with the 30 nm size Ag nanoparticles showed a short circuit current density of 12.97 mA/cm2, which is 0.53 mA/cm2 higher than that of the reference solar cell without Ag nanoparticles, and the highest quantum efficiency for wavelengths from 550 to 800 nm. When 30 nm size nanoparticles were employed, the conversion efficiency of the solar cell was increased from 6.195% to 6.696%. This study reports the application of the scattering effect of Ag nanoparticles for the improvement of the conversion efficiency of amorphous silicon solar cells. PMID:24266153

  7. Electron and hole drift mobility measurements on thin film CdTe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Long, Qi; Dinca, Steluta A.; Schiff, E. A. [Department of Physics, Syracuse University, Syracuse, New York 13244-1130 (United States); Yu, Ming; Theil, Jeremy [First Solar, Inc., 1035 Walsh Ave, Santa Clara, California 95050 (United States)

    2014-07-28

    We report electron and hole drift mobilities in thin film polycrystalline CdTe solar cells based on photocarrier time-of-flight measurements. For a deposition process similar to that used for high-efficiency cells, the electron drift mobilities are in the range of 10{sup ?1}–10{sup 0} cm{sup 2}/V s, and holes are in the range of 10{sup 0}–10{sup 1} cm{sup 2}/V s. The electron drift mobilities are about a thousand times smaller than those measured in single crystal CdTe with time-of-flight; the hole mobilities are about ten times smaller. Cells were examined before and after a vapor phase treatment with CdCl{sub 2}; treatment had little effect on the hole drift mobility, but decreased the electron mobility. We are able to exclude bandtail trapping and dispersion as a mechanism for the small drift mobilities in thin film CdTe, but the actual mechanism reducing the mobilities from the single crystal values is not known.

  8. Electron and hole drift mobility measurements on thin film CdTe solar cells

    International Nuclear Information System (INIS)

    We report electron and hole drift mobilities in thin film polycrystalline CdTe solar cells based on photocarrier time-of-flight measurements. For a deposition process similar to that used for high-efficiency cells, the electron drift mobilities are in the range of 10?1–100 cm2/V s, and holes are in the range of 100–101 cm2/V s. The electron drift mobilities are about a thousand times smaller than those measured in single crystal CdTe with time-of-flight; the hole mobilities are about ten times smaller. Cells were examined before and after a vapor phase treatment with CdCl2; treatment had little effect on the hole drift mobility, but decreased the electron mobility. We are able to exclude bandtail trapping and dispersion as a mechanism for the small drift mobilities in thin film CdTe, but the actual mechanism reducing the mobilities from the single crystal values is not known.

  9. Two-dimensional high efficiency thin-film silicon solar cells with a lateral light trapping architecture

    Science.gov (United States)

    Fang, Jia; Liu, Bofei; Zhao, Ying; Zhang, Xiaodan

    2014-08-01

    Introducing light trapping structures into thin-film solar cells has the potential to enhance their solar energy harvesting as well as the performance of the cells; however, current strategies have been focused mainly on harvesting photons without considering the light re-escaping from cells in two-dimensional scales. The lateral out-coupled solar energy loss from the marginal areas of cells has reduced the electrical yield indeed. We therefore herein propose a lateral light trapping structure (LLTS) as a means of improving the light-harvesting capacity and performance of cells, achieving a 13.07% initial efficiency and greatly improved current output of a-Si:H single-junction solar cell based on this architecture. Given the unique transparency characteristics of thin-film solar cells, this proposed architecture has great potential for integration into the windows of buildings, microelectronics and other applications requiring transparent components.

  10. Nanoimprint lithography for high-efficiency thin-film silicon solar cells.

    Science.gov (United States)

    Battaglia, Corsin; Escarré, Jordi; Söderström, Karin; Erni, Lukas; Ding, Laura; Bugnon, Grégory; Billet, Adrian; Boccard, Mathieu; Barraud, Loris; De Wolf, Stefaan; Haug, Franz-Josef; Despeisse, Matthieu; Ballif, Christophe

    2011-02-01

    We demonstrate high-efficiency thin-film silicon solar cells with transparent nanotextured front electrodes fabricated via ultraviolet nanoimprint lithography on glass substrates. By replicating the morphology of state-of-the-art nanotextured zinc oxide front electrodes known for their exceptional light trapping properties, conversion efficiencies of up to 12.0% are achieved for micromorph tandem junction cells. Excellent light incoupling results in a remarkable summed short-circuit current density of 25.9 mA/cm(2) for amorphous top cell and microcrystalline bottom cell thicknesses of only 250 and 1100 nm, respectively. As efforts to maximize light harvesting continue, our study validates nanoimprinting as a versatile tool to investigate nanophotonic effects of a large variety of nanostructures directly on device performance. PMID:21302973

  11. Cu(In,Ga)Se2 thin films processed by co-evaporation and their application into solar cells

    Scientific Electronic Library Online (English)

    J., Sastré-Hernández; M.E., Calixto; M., Tufiño-Velázquez; G., Contreras-Puente; A., Morales-Acevedo; G., Casados-Cruz; M.A., Hernández-Pérez; M.L., Albor-Aguilera; R., Mendoza-Pérez.

    2011-10-11

    Full Text Available Polycrystalline Cu(In,Ga)Se2 (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, makin [...] g 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 µm). 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 µm, 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.

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

    Science.gov (United States)

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

    2015-07-28

    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. PMID:26118756

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

    International Nuclear Information System (INIS)

    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 1.72–1.53 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 Voc = 700 mV, Jsc = 10.01 mA/cm2 and FF = 0.59.

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

    International Nuclear Information System (INIS)

    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 ? 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 ? cm) against a 20% cut in optical transmission

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

    Science.gov (United States)

    Mazur, M.; Szyma?ska, M.; Kaczmarek, D.; Kalisz, M.; Wojcieszak, D.; Domaradzki, J.; Placido, F.

    2014-05-01

    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.

  16. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Flexible Cu(In,Ga)Se2 thin-film solar cells for space application

    International Nuclear Information System (INIS)

    Thin film solar cells (TFSC) with Cu(In,Ga)Se2 (CIGS) as absorber layer have been produced on rigid glass substrates for the terrestrial market. There exist, however, different investigations for manufacturing of TFSC on flexible substrates in order to achieve very thin and highly flexible (rollable) solar cells. Besides their capability to open new terrestrial market segments, they are considered as competitive candidates for future flexible thin film space power generators compared to traditional crystalline solar cells. This paper explains the advantages of flexible TFSC for usage in space, including:-low mass and storage volume, -high power/mass ratio [>100 W/kg at array level], -high radiation resistance against proton and electron radiation and, -lower production costs. These cells can be produced on flexible conductive and insulating substrate materials and have efficiency potentials of up to 15%. We report on the current development steps to adopt the TFSC technology to space requirements as well as the first European industrial approach to the roll-to-roll production of flexible CIGS-TFSC on polyimide as substrate material. Stability issues in space environment concern not only the TFSC itself, but all system components such as interconnects, cell assembly and flexible blankets. The adhesion of the back-contact to the substrate, the emissivity control in the infrared wavelength range, the electrical contacting and interconnection as well as flexibling and interconnection as well as flexible encapsulation are currently under investigation and are discussed in the paper. The production costs for TFSC for space application can be further reduced by sharing resources for the production of flexible TFSC for the terrestrial market; namely by using both, the existing terrestrial investment in production facilities as well as the synergies in R and D

  18. Alkali-templated surface nanopatterning of chalcogenide thin films: a novel approach toward solar cells with enhanced efficiency.

    Science.gov (United States)

    Reinhard, Patrick; Bissig, Benjamin; Pianezzi, Fabian; Hagendorfer, Harald; Sozzi, Giovanna; Menozzi, Roberto; Gretener, Christina; Nishiwaki, Shiro; Buecheler, Stephan; Tiwari, Ayodhya N

    2015-05-13

    Concepts of localized contacts and junctions through surface passivation layers are already advantageously applied in Si wafer-based photovoltaic technologies. For Cu(In,Ga)Se2 thin film solar cells, such concepts are generally not applied, especially at the heterojunction, because of the lack of a simple method yielding features with the required size and distribution. Here, we show a novel, innovative surface nanopatterning approach to form homogeneously distributed nanostructures (<30 nm) on the faceted, rough surface of polycrystalline chalcogenide thin films. The method, based on selective dissolution of self-assembled and well-defined alkali condensates in water, opens up new research opportunities toward development of thin film solar cells with enhanced efficiency. PMID:25844923

  19. Fabrication of nanocrystal ink based superstrate-type CuInS2 thin film solar cells

    International Nuclear Information System (INIS)

    A CuInS2 (CIS) nanocrystal ink was applied to thin film solar cell devices with superstrate-type configuration. Monodispersed CIS nanocrystals were synthesized by a colloidal synthetic route and re-dispersed in toluene to form an ink. A spray method was used to coat CIS films onto conducting glass substrates. Prior to CIS film deposition, TiO2 and CdS thin films were also prepared as a blocking layer and a buffer layer, respectively. We found that both a TiO2 blocking layer and a CdS buffer layer are necessary to generate photoresponses in superstrate-type devices. The best power conversion efficiency (?1.45%) was achieved by the CIS superstrate-type thin film solar cell device with 200 and 100 nm thick TiO2 and CdS films, respectively. (paper)

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

    Science.gov (United States)

    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 %.

  1. Ion beam assisted sputter deposition of ZnO for silicon thin-film solar cells

    International Nuclear Information System (INIS)

    Ion beam assisted deposition (IBAD) is a promising technique for improving the material quality of ZnO-based thin films. The operation of an auxiliary Ar+ ion source during deposition of ZnO?:?Ga thin films by dc magnetron sputtering led to an improvement in crystalline texture, especially at low temperatures due to momentum transfer from the ions to the growing film. Etching of IBAD-ZnO?:?Ga films in diluted HCl revealed crater-like surface structures with crater diameters of up to 600 nm. These structures are usually achieved after deposition at high substrate temperatures. This is an indication that the grain structure was remarkably changed by bombarding these films during deposition in terms of increasing the compactness of the ZnO?:?Ga films. Subsequent annealing procedures led to an improvement in the electrical and optical properties. Hydrogenated microcrystalline silicon (µc-Si?:?H) solar cells exhibited enhanced efficiency as compared to cells on other low-temperature sputtered reference ZnO films. This improvement was ascribed to light trapping by the modified etching behaviour of the IBAD-ZnO?:?Ga films as well as improved transparency after the vacuum annealing step. (paper)

  2. Ion beam assisted sputter deposition of ZnO for silicon thin-film solar cells

    Science.gov (United States)

    Warzecha, M.; Köhl, D.; Wuttig, M.; Hüpkes, J.

    2014-03-01

    Ion beam assisted deposition (IBAD) is a promising technique for improving the material quality of ZnO-based thin films. The operation of an auxiliary Ar+ ion source during deposition of ZnO?:?Ga thin films by dc magnetron sputtering led to an improvement in crystalline texture, especially at low temperatures due to momentum transfer from the ions to the growing film. Etching of IBAD-ZnO?:?Ga films in diluted HCl revealed crater-like surface structures with crater diameters of up to 600 nm. These structures are usually achieved after deposition at high substrate temperatures. This is an indication that the grain structure was remarkably changed by bombarding these films during deposition in terms of increasing the compactness of the ZnO?:?Ga films. Subsequent annealing procedures led to an improvement in the electrical and optical properties. Hydrogenated microcrystalline silicon (µc-Si?:?H) solar cells exhibited enhanced efficiency as compared to cells on other low-temperature sputtered reference ZnO films. This improvement was ascribed to light trapping by the modified etching behaviour of the IBAD-ZnO?:?Ga films as well as improved transparency after the vacuum annealing step.

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

    International Nuclear Information System (INIS)

    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

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

    Czech Academy of Sciences Publication Activity Database

    Van??ek, Milan; Poruba, Aleš; Remeš, Zden?k; 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 Grant ostatní: EU FP7(XE) CP-IP 214134-2; EU FP6 ATHLET(XE) SES6-019670 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

  5. A study of the applicability of ZnO thin-films as anti-reflection coating on Cu2ZnSnS4 thin-films solar cell

    International Nuclear Information System (INIS)

    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 Cu2ZnSnS4 (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 MgF2. Sprayed ZnO thin-films as ARC show comparable performance with the sputtered samples.

  6. A study of the applicability of ZnO thin-films as anti-reflection coating on Cu2ZnSnS4 thin-films solar cell

    Science.gov (United States)

    Ray, Abhijit; Patel, Malkeshkumar; Tripathi, Brijesh; Kumar, Manoj

    2012-06-01

    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 Cu2ZnSnS4 (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 MgF2. Sprayed ZnO thin-films as ARC show comparable performance with the sputtered samples.

  7. Radiation damage of GaAs thin-film solar cells on Si substrates

    International Nuclear Information System (INIS)

    1-MeV electron irradiation damages in GaAs thin-film solar cells on Si substrates are examined for the first time. Damage constant for minority-carrier diffusion length in GaAs heteroepitaxial films on Si substrates is found to be the same as that in GaAs homoepitaxial films on GaAs substrates. This agreement suggests that GaAs/Si has the same defect introduction rate with radiation as GaAs/GaAs. The degradation of GaAs solar cells on Si with electron irradiation is less than that of GaAs solar cells on GaAs, because in the present, GaAs films on Si substrates have lower minority-carrier diffusion length compared to GaAs films on GaAs and these films are insensitive to radiation. The p+-p+-n AlGaAs-GaAs heteroface solar cell with junction depth of about 0.3 ?m is concluded to be useful for a high-efficiency and radiation-resistant solar cell fabricated on a Si substrate

  8. Reduced adverse effects on Si thin film solar cells caused by growth chamber air exposure

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Fan; Zhang, Lin; Zheng, Yi; Schimitt, Francimar; Tso, Alan; Li, Lipan; Tsuei, Lun; Yuan, Zheng; Shieh, Brian [Thin Film Solar Products Division, Applied Materials, Santa Clara, CA 95054 (United States)

    2010-06-15

    The cost of photovoltaic (PV) energy is reduced by increasing solar cell power conversion efficiency and decreasing manufacture cost. An effective way of lowering the cost of Si thin film solar cells (TFSC) is to grow panels on large-area substrates. In this paper we study the effect of air residual to Si TFSC grown on 5.7 m{sup 2} glass in plasma-enhanced chemical vapor deposition (PECVD) chambers. Structural and chemical analysis show that oxygen incorporated into the Si films behaved as impurity dopant in the hydrogenated microcrystalline Si ({mu}c-Si) layers and reduced the efficiency of amorphous Si (a-Si)/{mu}c-Si tandem junction solar cells when the film had oxygen concentration >2 x 10{sup 19} atoms/cm{sup 3}. Higher oxygen content further suppressed the {mu}c-Si crystallization. We found that hydrogen plasma treatment of process chamber before Si film deposition effectively reduced the adverse effects of air exposure and improved both film quality and solar cell performance. The hydrogen-treated chamber produced contamination-free, solar cells with consistent, initial efficiency >10%. (author)

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

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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. 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.

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

    Science.gov (United States)

    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.

  12. Polypyrrole thin films decorated with copper nanostructures as counter electrode for dye-sensitized solar cells

    Science.gov (United States)

    Ghani, Sheeba; Sharif, Rehana; Bashir, Saima; Zaidi, Azhar A.; Rafique, M. S.; Ashraf, Ayesha; Shahzadi, Shamaila; Rafique, Shaista; Kamboh, Afzal H.

    2015-05-01

    A two-step electrochemical polymerization method for the fabrication of polypyrrole (PPY) thin films decorated with copper nanostructures on a stainless steel has been employed. The PPY film thickness affects the size, shape, and the number density of the copper nanostructures and provides an easy approach to control the morphology of these nanostructures. SEM images show nanorod like structures of copper on 200 nm PPY film. By employing this composite film as counter electrode (CE), a dye-sensitized solar cell (DSSC) achieves a conversion efficiency of 7.42%, which is greater than Pt CE based DSSC (5.63%). The superior photovoltaic efficiency for the Cu-PPY film is attributed to unique porous PPY thin film and copper nanorods structure that leads to higher cathodic current density (5.38 mA/cm2), large electrocatalytic activity, and small charge transfer resistance(1.92 ? cm-2). Therefore, Cu-PPY composite can be considered a competitive and promising CE material with the traditional and expensive Pt CE, for large-scale DSSCs production.

  13. Electrodeposition of wide band gap InGaxSyOz thin films for solar cell applications

    International Nuclear Information System (INIS)

    Indium-Gallium-sulfide-oxide thin films were deposited onto F-doped SnO2-coated glass by electrochemical deposition from an aqueous bath. The films were deposited at three different ratios of gallium to indium in the precursor bath; namely [Ga/In] = 2/8, 5/5 and 8/2. The impact of the gallium content on the composition, optical transmission, structure, photosensitivity, electrical resistivity and morphology of the deposited films was investigated. The films deposited at [Ga/In] = 5/5 and 8/2 had an energy gap as high as 3.5 eV. The X-ray diffraction spectrum of the film deposited at [Ga/In] = 2/8 contained weak peaks of indium metal, but the In peaks were absent in the spectra of the films deposited at [Ga/In] = 5/5 and 8/2. The photosensitivity of the film was observed by means of photoelectrochemical measurements, which confirmed that all the films showed n-type conduction. Finally, the film has been used as a buffer layer to fabricate a SnS-based thin film solar cell.

  14. Formation of thin films of organic-inorganic perovskites for high-efficiency solar cells.

    Science.gov (United States)

    Stranks, Samuel D; Nayak, Pabitra K; Zhang, Wei; Stergiopoulos, Thomas; Snaith, Henry J

    2015-03-01

    Organic-inorganic perovskites are currently one of the hottest topics in photovoltaic (PV) research, with power conversion efficiencies (PCEs) of cells on a laboratory scale already competing with those of established thin-film PV technologies. Most enhancements have been achieved by improving the quality of the perovskite films, suggesting that the optimization of film formation and crystallization is of paramount importance for further advances. Here, we review the various techniques for film formation and the role of the solvents and precursors in the processes. We address the role chloride ions play in film formation of mixed-halide perovskites, which is an outstanding question in the field. We highlight the material properties that are essential for high-efficiency operation of solar cells, and identify how further improved morphologies might be achieved. PMID:25663077

  15. Study of thin-film silicon solar cells at irradiances above ten thousand suns

    International Nuclear Information System (INIS)

    We used a tightly focused Gaussian beam of a HeNe laser to study accelerated light-induced degradation (Staebler-Wronski effect) and high photocarrier generation rates in amorphous and microcrystalline silicon thin-film solar cells, at up to13 MW/m2 irradiance. For the experiments, the spot radius was varied from a minimum of 8.6 ?m in the focus to around 1 mm away from the focus. According to COMSOL'' (registered) simulations, even at these high power densities heat diffusion into a glass substrate aided by spreading conduction via the Ag back-contact restricts the temperature rise to less than 14 K. Short-circuit current can be measured directly over a range of irradiances, and the J-V characteristic may be estimated by taking into account shunting by the inactive part of the cell.

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

    International Nuclear Information System (INIS)

    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 ? 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 ? 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.

  17. Thin film solar energy collector

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Karaagac, Hakan, E-mail: hkaraagac@ucdavis.edu [Department of Electrical and Computer Engineering, University of California at Davis, Davis, CA 95616 (United States); Department of Physics, Middle East Technical University, 06531 Ankara (Turkey); Parlak, Mehmet [Department of Physics, Middle East Technical University, 06531 Ankara (Turkey); Yengel, Emre; Islam, M. Saif [Department of Electrical and Computer Engineering, University of California at Davis, Davis, CA 95616 (United States)

    2013-06-15

    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 AgGa{sub 0.5}In{sub 0.5}Se{sub 2} 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{sup ?2}, 63% and 5.50%, respectively. On the other hand, these respective parameters were 0.26 V, 3.18 mA cm{sup ?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.

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

    International Nuclear Information System (INIS)

    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

    International Nuclear Information System (INIS)

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

  2. Effective Ag doping by He-Ne laser exposure to improve the electrical and the optical properties of CdTe thin films for heterostructured thin film solar cells

    International Nuclear Information System (INIS)

    The cadmium telluride (CdTe) thin film solar cell is one of the strongest candidates due to the optimum band gap energy (about 1.4 eV) for solar energy absorption, high light absorption capability and lower cost requirements for solar cell production. However, the maximum efficiency of a CdTe thin film solar cell still remains just 16.5% despite its excellent absorption coefficient; i.e., the electrical properties of CdTe thin film, including the resistivity, must be improved to enhance the energy conversion efficiency. Silver (Ag) was doped by using helium-neon (He-Ne) laser (632.8 nm) exposure into sputtering-deposited p-type CdTe thin films. The resistivity of the Ag-doped CdTe thin films was reduced from 2.97 x 104 ?-cm to the order of 5.16 x 10'-'2 ?-cm. The carrier concentration of CdTe thin films had increased to 1.6 x 1018 cm-3 after a 15-minute exposure to the He-Ne laser. The average absorbance value of CdTe thin films was improved from 1.81 to 3.01 by the doping of Ag due to impurity-scattering. These improved properties should contribute to the efficiency of the photovoltaic effect of the photogenerated charged carriers. The methodology in this study is very simple and effective to dope a multilayered thin film solar cell with a relatively short process time, no wet-process, and selective treatment.

  3. Deposition and doping of CdS/CdTe thin film solar cells

    Science.gov (United States)

    Gorji, Nima E.

    2015-05-01

    1% oxygen is incorporated into both CdS and CdTe layers through RF sputtering of CdS/CdTe thin film solar cells. The optical and electrical parameters of the oxygenated and O2-free devices are compared after CdCl2 treatment and annealing in ambient Ar and/or air. The effects of ambient annealing on the electrical and optical properties of the films are investigated using current—voltage characterization, field emission scanning electron microscopy, X-ray diffraction, and optical transmission spectroscopy. The 1% oxygen content can slightly increase the grain size while the crystallinity does not change. Annealing in ambient Ar can increase the transmission rate of the oxygenated devices.

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

    International Nuclear Information System (INIS)

    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%.

  5. Spin Coated Plasmonic Nanoparticle Interfaces for Photocurrent Enhancement in Thin Film Si Solar Cells

    CERN Document Server

    Israelowitz, Miriam; Cong, Tao; Sureshkumar, Radhakrishna

    2013-01-01

    Nanoparticle (NP) arrays of noble metals strongly absorb light in the visible to infrared wavelengths through resonant interactions between the incident electromagnetic field and the metal's free electron plasma. Such plasmonic interfaces enhance light absorption and photocurrent in solar cells. We report a cost effective and scalable room temperature/pressure spin-coating route to fabricate broadband plasmonic interfaces consisting of silver NPs. The NP interface yields photocurrent enhancement (PE) in thin film silicon devices by up to 200% which is significantly greater than previously reported values. For coatings produced from Ag nanoink containing particles with average diameter of 40 nm, an optimal NP surface coverage of 7% was observed. Scanning electron microscopy of interface morphologies revealed that for low surface coverage, particles are well-separated, resulting in broadband PE. At higher surface coverage, formation of particle strings and clusters caused red-shifting of the PE peak and a narro...

  6. Light absorption enhancement in thin-film solar cells by embedded lossless silica nanoparticles

    International Nuclear Information System (INIS)

    Embedded silica nanoparticles in thin-film silicon solar cells have some advantages over metal nanoparticles in enhancing optical absorption of silicon such as no loss, better compatibility with antireflection coating and extremely low dangling bond densities and interface recombination velocities. To the best of our knowledge, we have carried out the first systematic study of optical absorption enhancement with silica nanoparticles of different radii, array periods and depths in the silica substrate with the finite-difference time-domain method, and we have obtained the optimum values of the nanoparticle parameters. We discuss the physical mechanism of the optical absorption enhancement in detail and attribute the enhancement to the superposition of the particle scattering effect and the Fabry–Perot resonance effect. (paper)

  7. Organic solar cells based on liquid crystalline and polycrystalline thin films

    Science.gov (United States)

    Yoo, Seunghyup

    This dissertation describes the study of organic thin-film solar cells in pursuit of affordable, renewable, and environmentally-friendly energy sources. Particular emphasis is given to the molecular ordering found in liquid crystalline or polycrystalline films as a way to leverage the efficiencies of these types of cells. Maximum efficiencies estimated based on excitonic character of organic solar cells show power conversion efficiencies larger than 10% are possible in principle. However, their performance is often limited due to small exciton diffusion lengths and poor transport properties which may be attributed to the amorphous nature of most organic semiconductors. Discotic liquid crystal (DLC) copper phthalocyanine was investigated as an easily processible building block for solar cells in which ordered molecular arrangements are enabled by a self-organization in its mesophases. An increase in photocurrent and a reduction in series resistance have been observed in a cell which underwent an annealing process. X-ray diffraction (XRD) and atomic force microscopy (AFM) measurements suggest that structural and morphological changes induced after the annealing process are related to these improvements. In an alternative approach, p-type pentacene thin films prepared by physical vapor deposition were incorporated into heterojunction solar cells with C60 as n-type layers. Power conversion efficiencies of 2.7% under broadband illumination (350--900 nm) with a peak external quantum efficiency of 58% have been achieved with the broad spectral coverage across the visible spectrum. Analysis using an exciton diffusion model shows this efficient carrier generation is mainly due to the large exciton diffusion length of pentacene films. Joint XRD and AFM studies reveal that the highly crystalline nature of pentacene films can account for the observed large exciton diffusion length. In addition, the electrical characteristics are studied as a function of light intensity using the equivalent circuit model used for inorganic pn-junction solar cells. Dependences of equivalent-circuit parameters on light intensity are further investigated using a modified equivalent circuit model, and their effects on the overall photovoltaic performance are discussed.

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

    OpenAIRE

    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...

  9. Overview and Challenges of Thin Film Solar Electric Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Ullal, H. S.

    2008-12-01

    In this paper, we report on the significant progress made worldwide by thin-film solar cells, namely, amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). Thin-film photovoltaic (PV) technology status is also discussed in detail. In addition, R&D and technology challenges in all three areas are elucidated. The worldwide estimated projection for thin-film PV technology production capacity announcements are estimated at more than 5000 MW by 2010.

  10. Electron backscatter diffraction: An important tool for analyses of structure-property relationships in thin-film solar cells

    OpenAIRE

    Abou-ras, D.; Kavalakkatt, J.; Nichterwitz, M.; Scha?fer, N.; Harndt, S.; Wilkinson, AJ; Tsyrulin, K.; Schulz, H.; Bauer, F.

    2013-01-01

    The present work gives an overview of the application of electron backscatter diffraction (EBSD) in the field of thin-film solar cells, which consist of stacks of polycrystalline layers on various rigid or flexible substrates. EBSD provides access to grain-size and local-orientation distributions, film textures, and grain-boundary types. By evaluation of the EBSD patterns within individual grains of the polycrystalline solar cell layers, microstrain distributions also can be obtained. These m...

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

    Science.gov (United States)

    Yuan, Ji-Ren; Shen, Hong-Lie; Zhou, Lang; Huang, Hai-Bin; Zhou, Nai-Gen; Deng, Xin-Hua; Yu, Qi-Ming

    2014-03-01

    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.

  12. Transparent sculptured titania films for enhanced light absorption in thin-film Si solar cells

    International Nuclear Information System (INIS)

    This study presents a description of the enhancement of light absorption in thin-film silicon (Si) solar cells by using sculptured titania (TiO2) films. We used an electron-beam evaporation system with a glancing angle deposition (GLAD) method to deposit porous TiO2 films on fluorine-doped SnO2 (FTO) substrates. The GLAD TiO2/FTO films were used as conductive electrodes in hydrogenated microcrystalline silicon (?c-Si:H) solar cells. Transmission electron microscopy revealed that the GLAD TiO2 films are composed of sculptured nano-pillars on an FTO surface, and this nanostructure provides a synergistic route for light scattering enhancement. The GLAD TiO2/FTO exhibited a 68% improvement of optical haze (at ? = 600 nm). The ?c-Si:H solar cells consisting of the GLAD-nanostructured TiO2 resulted in a 5% improvement of short-circuit current (Jsc) and yielded a cell efficiency of 6.6%.

  13. Electronic grain boundary properties in polycrystalline Cu(In,Ga)Se2 semiconductors for thin film solar cells

    International Nuclear Information System (INIS)

    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 ?3 GBs have a lower probability to possess a charged potential barrier than lower symmetric non-?3 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 ?3, could help to explain the large variations of potential barriers observed at GBs in polycrystalline CIGSe thin films.

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

    Science.gov (United States)

    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

  15. Dyadic Green’s functions of thin films: Applications within plasmonic solar cells

    DEFF Research Database (Denmark)

    Jung, Jesper; SØndergaard, Thomas

    2011-01-01

    Optimization and design of silicon solar cells by exploiting light scattering frommetal nanoparticles to increase the efficiency is addressed in the small particle limit from a fundamental point of view via the dyadic Green’s function formulation. Based on the dyadic Green’s function (Green’s tensor) of a three-layer geometry, light scattering from electric point dipoles (representing small metal scatterers) located within a thin layer sandwiched between a substrate and a superstrate is analyzed. Starting from the full dyadic Green’s function we derive analytical near- and far-field approximations. The far-field approximations enable efficient, exact, and separate evaluation of light scattering into waves that propagate in the substrate or the superstrate. Based on the near-field approximation we present a semianalytical expression for the total near-field absorption in the substrate. The theoretical approach is used to analyze realistic configurations for plasmon-assisted silicon solar cells. We showthat by embedding metal nanoscatterers in a thin film with a high refractive index (rutile TiO2 with n ? 2.5) on top of the silicon, the fraction of scattered light that couples into the solar cell can become larger than 96%, and an optical path length enhancement of more than 100 can be achieved.

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

    International Nuclear Information System (INIS)

    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.

  17. Efficient light scattering in plasmonic light trapping designs for thin film solar cells

    Science.gov (United States)

    Ji, Liming; Varadan, Vasundara V.

    2015-04-01

    Plasmonic structures have been proposed for enhancing light absorption in thin film solar cells, for which insufficient light absorption is a limiting factor for further improvement of efficiency. The optical path of light in the absorber layer of a solar cell is increased due to the enhanced light scattering by plasmonic structures at resonance. This process involves two steps of energy conversion: light-electron and then electron-light. The first step couples optical energy into the kinetic energy of collective electron motions in plasmonic structures, forming oscillating current. This step is easy to implement as long as plasmonic structures are at resonance. The second step releases the energy from electrons to photons. An efficient release of photon energy is a must for solar cell applications and it is dependent on the two competing effects: light scattering and field localization that results in heat loss. Theoretical discussions and simulation work are provided in the paper. The scattering of light by a plasmonic structure is analyzed based on the antenna radiation theory. Three factors are found to be important for the efficiency of a plasmonic light trapping design: the radiation of each unit structure, the array factor and the energy feeding of the structure. An efficient plasmonic light trapping design requires proper considerations of all the three factors.

  18. Modification of opto-electronic properties of ZnO by incorporating metallic tin for buffer layer in thin film solar cells

    Science.gov (United States)

    Deepu, D. R.; Jubimol, J.; Kartha, C. Sudha; Louis, Godfrey; Kumar, K. Rajeev; Vijayakumar, K. P.

    2015-06-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Nanostructured p-type CZTS thin films prepared by a facile solution process for 3D p-n junction solar cells.

    Science.gov (United States)

    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

    2015-06-18

    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. PMID:26061271

  1. Band offset of high efficiency CBD-ZnS/CIGS thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Nakada, Tokio; Hongo, Masashi; Hayashi, Eiji

    2003-05-01

    The band offset at the CBD-ZnS/Cu(In,Ga)Se{sub 2} (CIGS) interface and solar cells performance were investigated by means of X-ray photoelectron spectroscopy (XPS). The valence band maximum and valence band offset at the chemical bath deposition (CBD)-ZnS/CIGS interface region was directly measured using a XPS spectral multiplot. We found that the conduction band offset (CBO) at the CBD-ZnS/CIGS (ordered vacancy compound, OVC) interface was smaller than that of the evaporated ZnS/CIGS (OVC) interface. However, the CBO for the CBD-ZnS/CIGS (OVC) interface was still quite large for fabrication of high efficiency devices, although, in fact, high efficiency CBD-ZnS/CIGS devices were fabricated with good run-to-run reproducibility. The bandgap dependence of cell performance for CBD-ZnS/CIGS devices (large CBO) showed a tendency similar to that of CBD-CdS/CIGS devices (small CBO). Therefore, the observed decrease in cell performance for high bandgap devices is not interpreted in terms of the CBO. These results suggest that the band offset is not the predominant factor in achieving high efficiency CBD-ZnS/CIGS thin film solar cells. This finding suggests that the recombination mechanism of those wide-gap alloys is a bulk recombination.

  2. Band offset of high efficiency CBD-ZnS/CIGS thin film solar cells

    International Nuclear Information System (INIS)

    The band offset at the CBD-ZnS/Cu(In,Ga)Se2 (CIGS) interface and solar cells performance were investigated by means of X-ray photoelectron spectroscopy (XPS). The valence band maximum and valence band offset at the chemical bath deposition (CBD)-ZnS/CIGS interface region was directly measured using a XPS spectral multiplot. We found that the conduction band offset (CBO) at the CBD-ZnS/CIGS (ordered vacancy compound, OVC) interface was smaller than that of the evaporated ZnS/CIGS (OVC) interface. However, the CBO for the CBD-ZnS/CIGS (OVC) interface was still quite large for fabrication of high efficiency devices, although, in fact, high efficiency CBD-ZnS/CIGS devices were fabricated with good run-to-run reproducibility. The bandgap dependence of cell performance for CBD-ZnS/CIGS devices (large CBO) showed a tendency similar to that of CBD-CdS/CIGS devices (small CBO). Therefore, the observed decrease in cell performance for high bandgap devices is not interpreted in terms of the CBO. These results suggest that the band offset is not the predominant factor in achieving high efficiency CBD-ZnS/CIGS thin film solar cells. This finding suggests that the recombination mechanism of those wide-gap alloys is a bulk recombination

  3. Modelling of two-and four-terminal thin-film silicon tandem solar cells

    International Nuclear Information System (INIS)

    We have performed semi-empirical modelling of amorphous silicon/microcrystalline silicon thin-film solar cells in tandem optical configuration, under series (two-terminal) and independent (four-terminal) electrical connection. The four-terminal connection relaxes the constraint of current matching between the cells. Computer simulations indicate an increase in maximum initial efficiency from 10.0% (two-terminal) to 10.8% (four-terminal). Following degradation of the amorphous silicon top-cell the figures are 8.5% and 9.8% respectively, with an optimum top-cell absorber layer thickness in four-terminal connection of 150 nm. Changes in solar spectral quality have been simulated by applying weighted spectra, and improvements in efficiency favouring four-terminal connection occur under red- and blue-rich conditions. However, these typically convey only a small fraction of the total annual insolation, and gains of 5% or less in annual electrical output are predicted. Possible increased optical and electrical losses due to additional contact layers in four-terminal connection are not taken into account.

  4. Quantitative analysis of the contribution of nanocone gratings to the efficiency of crystalline Si thin-film solar cells

    International Nuclear Information System (INIS)

    Quantitative analysis of the contribution from different physics mechanisms induced by nanocone gratings (NCG) to the efficiency of crystalline Si thin-film solar cells is systematically demonstrated through the performance comparison of such a nanotextured Si solar cell, an equivalent reflection planar Si solar cell, an equivalent volume planar Si solar cell and an actually planar Si solar cell, when their back-interface is a perfect-matched layer or air and their thickness is 1 µm or 10 µm. The results indicate that the contribution of each physics mechanism to the ultimate efficiency and their total contribution are significantly influenced by the thickness of their active layer. When the height of the NCG structure is comparable to the thickness of the active layer, the contribution from each physics mechanism to the efficiency must be considered. In that respect, the contribution from the guided-mode resonance effect is the largest, and even surpasses the contribution of the active layer itself. When the active layer is significantly thicker than the height of the NCG structure, the contribution from antireflection induced by such a nanostructure rises up to the most, and the volume reduction effect can be ignored. In addition, the cavity-resonance effect exhibits a weak contribution and seems to be insensitive to the active layer thickness and interface reflection. Such an investigation provides a methodology to optimize nanostructure-textured thin-film solar nanostructure-textured thin-film solar cells. Furthermore, the comparison of efficiency between a 1 µm thick NCG-textured solar cell and a 10 µm thick planar solar cell indicates that higher efficiency can be achieved in a thinner Si solar cell by the use of the optimized NCG structure, which just fulfils the expectation of third generation of Si solar cells. (paper)

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

    OpenAIRE

    So?derstro?m, Karin; Bugnon, Gre?gory; 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...

  6. Thin-film silicon solar cells applying optically decoupled back reflectors

    International Nuclear Information System (INIS)

    Thin-film silicon solar cells often apply a metal back reflector (BR) separated from the silicon layers by a thin rear dielectric of thickness around 80 nm or a white paint combined with a thick rear dielectric of several micrometers. In this work, we investigate the optical performance of microcrystalline silicon (?c-Si:H) solar cells applying BRs of various topographies. In contrast to a standard 80 nm-ZnO/Ag BR design, for which the BR nearly strictly follows the texture of the underlying ?c-Si:H layers, placing the Ag BR far from the ?c-Si:H layers allows for a variation of the BR topography. Irrespective of the investigated BR topographies and also for a conventional white paint BR, long distances (of several micrometers) between the BR and the ?c-Si:H layers are found to be detrimental for the light trapping. Optical simulations based on both rigorous and scalar scattering theory have been performed to understand the impact of the diverse BR designs on the optical cell performance

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

  9. Preparation of CulnS2 Thin Films on the Glass Substrate by DC Sputtering for Solar Cell Component

    International Nuclear Information System (INIS)

    The CuInS2 alloys were deposited on glass substrate using plasma DC sputtering technique. A CuInS2 alloy target was made from Cu, In, Se powder with impurity of 99.998%. The deposition process was done with the following process parameter variations: deposition time and substrate temperature were the range of 15 to 45 min and 150 to 300 ?, the gas pressure was kept at 1.4x10-1 Torr. The purpose of the research is to obtain the solar cell component of CuInS2 thin films. The electrical and optical properties measurement has been done by four-point probe and UV-Vis. Crystal structure was analyzed using X-ray diffraction (XRD). The result shows that minimum resistance of CuInS2 thin films is 35.7 k? and optical transmittance is 14.7 %. The crystal structure of CuInS2 is oriented at (112) plane and by Touc-plot method was obtained that the band gap energy of thin films is 1.45 eV. It could be concluded that the CuInS2 thin film can be used as a solar cell component. (author)

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

    Science.gov (United States)

    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.

  11. AgSb(SxSe1?x)2 thin films for solar cell applications

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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)

  13. Characterisation of photovoltaic modules based on thin film solar cells in environmental operating conditions of Algerian Sahara

    Science.gov (United States)

    Agroui, K.; Hadj Mahammed, I.; Hadj Arab, A.; Belghachi, A.

    2008-08-01

    This paper summarizes the electrical and thermal characterizations of thin film PV modules based on amorphous triple junctions (3J: a-Si) and Copper Indium Selenide (CIS) thin film solar cells. Tests are operated in outdoor exposure and under natural sunlight of Ghardaia, Algeria) as specific desert climate environment, characterized by high irradiation and temperature levels. Data acquired from Environmental Operating Conditions (EOC) was converted into solar module output characteristics at Standard Test Conditions (STC) by using three method suggested by Anderson and Mermoud as well as the equations already standardized as IEC 60891. Then, based on the investigation results of the conversion equations, differences among the converting methods (range of application, specificity of solar cell material, and experimental test conditions) were studied.

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

    International Nuclear Information System (INIS)

    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. CdTe thin film solar cells with reduced CdS film thickness

    International Nuclear Information System (INIS)

    A study was performed to reduce the CdS film thickness in CdTe thin film solar cells to minimize losses in quantum efficiency. Using close space sublimation deposition for CdS and CdTe a maximum efficiency of ? 9.5% was obtained with the standard CdS film thickness of ? 160 nm. Reduction of the film CdS thickness to less than 100 nm leads to poor cell performance with ? 5% efficiency, mainly due to a lower open circuit voltage. An alternative approach has been tested to reduce the CdS film thickness (? 80 nm) by depositing a CdS double layer. The first CdS layer was deposited at high substrate temperature in the range of 520-540 deg. C and the second CdS layer was deposited at low substrate temperature of ? 250 deg. C. The cell prepared using a CdS double layer show better performance with cell efficiency over 10%. Quantum efficiency measurement confirmed that the improvement in the device performance is due to the reduction in CdS film thickness. The effect of double layer structure on cell performance is also observed with chemical bath deposited CdS using fluorine doped SnO2 as substrate.

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

    Directory of Open Access Journals (Sweden)

    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.

  17. Electrophoretic deposited TiO2 pigment-based back reflectors for thin film solar cells.

    Science.gov (United States)

    Bills, Braden; Morris, Nathan; Dubey, Mukul; Wang, Qi; Fan, Qi Hua

    2015-02-01

    Highly reflective coatings with strong light scattering effect have many applications in optical components and optoelectronic devices. This work reports titanium dioxide (TiO2) pigment-based reflectors that have 2.5 times higher broadband diffuse reflection than commercially produced aluminum or silver based reflectors and result in efficiency enhancements of a single-junction amorphous Si solar cell. Electrophoretic deposition is used to produce pigment-based back reflectors with high pigment density, controllable film thickness and site-specific deposition. Electrical conductivity of the pigment-based back reflectors is improved by creating electrical vias throughout the pigment-based back reflector by making holes using an electrical discharge / dielectric breakdown approach followed by a second electrophoretic deposition of conductive nanoparticles into the holes. While previous studies have demonstrated the use of pigment-based back reflectors, for example white paint, on glass superstrate configured thin film Si solar cells, this work presents a scheme for producing pigment-based reflectors on complex shape and flexible substrates. Mechanical durability and scalability are demonstrated on a continuous electrophoretic deposition roll-to-roll system which has flexible metal substrate capability of 4 inch wide and 300 feet long. PMID:25836255

  18. Numerical 3D-simulation of micromorph silicon thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Geissendoerfer, Stefan; Lacombe, Juergen; Maydell, Karsten von; Agert, Carsten [EWE-Forschungszentrum fuer Energietechnologie e.V. NEXT ENERGY, Carl-von-Ossietzky-Str. 15, 26129 Oldenburg (Germany)

    2011-07-01

    In this contribution 3-dimensional simulations of micromorph silicon thin film solar cells, which have a tandem structure consisting of amorphous and microcrystalline subcells, are presented. The variety of different active layers leads to a very complex structure. Additionally, randomly textured surfaces and interfaces have to be taken into account. Our goal is to create physical models to describe the coupled optical and electrical behaviour of the whole structure in three dimensions to determine the theoretical limits and dominant material parameters. To simulate solar cells with rough interfaces, the surfaces topography was measured via atomic force microscopy (AFM) and transferred to the commercial software Sentaurus TCAD from the company Synopsys. The virtual structure includes layer thicknesses and optoelectronic parameters. Results of the space resolved optical generation rates by using the optical solver ''Raytracer'' are presented. The space resolved optical generation rate inside the semiconductor layers depends on the structure of the TCO interface. Therefore, regions with higher charge carrier densities can be observed which has an influence on the current transport through the stack. These investigations and the influence to the IV characteristic are presented.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    Gerlach, D; Wimmer, M; Wilks, R G; Félix, R; Kronast, F; Ruske, F; Bär, 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. Quantitative determination of element distributions in silicon based thin film solar cells using SNMS

    Energy Technology Data Exchange (ETDEWEB)

    Gastel, M. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen; Breuer, U. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen; Holzbrecher, H. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen; Becker, J.S. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen; Dietze, H.J. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen; Kubon, M. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Schicht- und Ionentechnik; Wagner, H. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Schicht- und Ionentechnik

    1995-10-01

    The determination of elemental distributions in thin film solar cells based on amorphous silicon using electron beam SNMS is possible by quantifying the measured ion intensities. The relative sensitivity factors (RSFs) for all elements measured have to be known. The RSFs have been determined experimentally using implantation and bulk standards with known concentrations of the interesting elements. The measured RSFs have been compared with calculated RSFs. The model used for the calculation of the RSFs takes into account the probability for electron impact ionization and the dwell time of the neutrals inside the postionization region. The comparison between measured and calculated RSF shows, that this model is capable to explain the RSFs for most elements. Differences between calculated and measured values can be explained by the formation of hydride and fluoride molecules (in case of H and F) and influences of the angular distribution of the sputtered neutrals in case of Al. The experimentally determined RSFs have been used for a quantification of depth profiles of the i-, buffer-, p- and front contact layers of a-Si solar cells. (orig.)

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

    OpenAIRE

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

    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 ...

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

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

    Tripathi, Brijesh; Patel, Malkesh; Ray, Abhijit; Kumar, Manoj

    2013-05-01

    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.

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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 ? 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    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})

  8. Fabrication and photovoltaic characteristics of Cu2O/TiO2 thin film heterojunction solar cell

    International Nuclear Information System (INIS)

    A p-Cu2O/n-TiO2 thin film heterojunction solar cell has been fabricated by electrodeposition of Cu2O on radio-frequency sputtered n-TiO2 thin film. The heterojunction solar cell was characterized by X-ray diffraction, scanning electron microscopy and UV spectroscopy. Capacitance–voltage (C–V) and current–voltage measurements were performed. The values of barrier height and carrier concentration were estimated from the reverse bias C–V. The transport mechanism is related to space charge limited current and a trapped charge limited current having slope values of 1.95 and 3.5. Impedance measurement showed that electrical resistance decreases when the voltage is increased. The energy band diagram shows that the main-band discontinuity forms in the valence band. The ideality factor, barrier height and series resistance, fill factor and efficiency were also measured. The heterojunction solar cell exhibits a maximum fill factor and a power conversion efficiency of about 0.35 and 0.15% respectively. - Highlights: ? p-Cu2O/n-TiO2 thin film heterojunction was fabricated. ? Conduction and valance band discontinuities were measured. ? The maximum efficiency of solar cell was measured to be 0.15%. ? The defects, band discontinuity and large mismatch caused low efficiency.

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

    CERN Document Server

    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.

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

    International Nuclear Information System (INIS)

    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)

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

    Directory of Open Access Journals (Sweden)

    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.

  12. Advances in Evaporated Solid-Phase-Crystallized Poly-Si Thin-Film Solar Cells on Glass (EVA)

    OpenAIRE

    A. G. Aberle; Wong, J; Ouyang, Z.; Kunz, O.

    2008-01-01

    Polycrystalline silicon thin-film solar cells on glass obtained by solid-phase crystallization (SPC) of PECVD-deposited a-Si precursor diodes are capable of producing large-area devices with respectable photovoltaic efficiency. This has not yet been shown for equivalent devices made from evaporated Si precursor diodes (“EVA” solar cells). We demonstrate that there are two main problems for the metallization of EVA solar cells: (i) shunting of the p-n junction when the air-side metal...

  13. Unlinking absorption and haze in thin film silicon solar cells front electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Boccard, Mathieu; Cuony, Peter; Battaglia, Corsin; Despeisse, Matthieu; Ballif, Christophe [Ecole Polytechnique Federale de Lausanne (EPFL), Institute of Microengineering (IMT), Photovoltaics and Thin Film Electronics Laboratory, Rue A.-L. Breguet 2, 2000 Neuchatel (Switzerland)

    2010-11-15

    We study the respective influence of haze and free carrier absorption (FCA) of transparent front electrodes on the photogenerated current of micromorph thin film silicon solar cells. To decouple the haze and FCA we develop bi-layer front electrodes: a flat indium tin oxide layer assures conduction and allows us to tune FCA while the haze is adjusted by varying the thickness of a highly transparent rough ZnO layer. We show how a minimum amount of FCA leads only to a few percents absorption for a single light path but to a strong reduction of the cell current in the infrared part of the spectrum. Conversely, a current enhancement is shown with increasing front electrode haze up to a saturation of the current gain. This saturation correlates remarkably well with the haze of the front electrode calculated in silicon. This allows us to clarify the requirements for the front electrodes of micromorph cells. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Novel R2R Manufacturable Photonic-Enhanced Thin Film Solar Cells; January 28, 2010 -- January 31, 2011

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. A blazed grating for light trapping in a-Si thin-film solar cells

    International Nuclear Information System (INIS)

    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)

  16. Broadband light trapping in thin film solar cells with self-organized plasmonic nano-colloids

    Science.gov (United States)

    Mendes, Manuel J.; Morawiec, Seweryn; Mateus, Tiago; Lyubchyk, Andriy; Águas, Hugo; Ferreira, Isabel; Fortunato, Elvira; Martins, Rodrigo; Priolo, Francesco; Crupi, Isodiana

    2015-03-01

    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.

  17. Selective ablation with UV lasers of a-Si:H thin film solar cells in direct scribing configuration

    OpenAIRE

    Lauzurica Santiago, Sara; García-Ballesteros Ramírez, Juan José; Colina Brito, Mónica; Sanchez Aniorte, Maria Isabel; Molpeceres Alvarez, Carlos Luis

    2011-01-01

    Monolithical series connection of silicon thin-film solar cells modules performed by laser scribing plays a very important role in the entire production of these devices. In the current laser process interconnection the two last steps are developed for a configuration of modules where the glass is essential as transparent substrate. In addition, the change of wavelength in the employed laser sources is sometimes enforced due to the nature of the different materials of the multilayer structure...

  18. Thin-film monocrystalline-silicon solar cells based on a seed layer approach with 11% efficiency

    Science.gov (United States)

    Gordon, I.; Qiu, Y.; Van Gestel, D.; Poortmans, J.

    2010-09-01

    Solar modules made from thin-film crystalline-silicon layers of high quality on glass substrates could lower the price of photovoltaic electricity substantially. Almost half of the price of wafer-based silicon solar modules is currently due to the cost of the silicon wafers themselves. Using crystalline-silicon thin-film as the active material would substantially reduce the silicon consumption while still ensuring a high cell-efficiency potential and a stable cell performance. One way to create a crystalline-silicon thin film on glass is by using a seed layer approach in which a thin crystalline-silicon layer is first created on a non-silicon substrate, followed by epitaxial thickening of this layer. In this paper, we present new solar cell results obtained on 10-micron thick monocrystalline-silicon layers, made by epitaxial thickening of thin seed layers on transparent glass-ceramic substrates. We used thin (001)-oriented silicon single-crystal seed layers on glass-ceramic substrates provided by Corning Inc. that are made by a process based on anodic bonding and implant-induced separation. Epitaxial thickening of these seed layers was realized in an atmospheric-pressure chemical vapor deposition system. Simple solar cell structures in substrate configuration were made from the epitaxial mono-silicon layers. The Si surface was plasma-textured to reduce the front-side reflection. No other light trapping features were incorporated. Efficiencies of up to 11% were reached with Voc values above 600 mV indicating the good electronic quality of the material. We believe that by further optimizing the material quality and by integrating an efficient light trapping scheme, the efficiency potential of these single-crystal silicon thin films on glass-ceramics should be higher than 15%.

  19. Micromorph thin-film silicon solar cells with transparent high-mobility hydrogenated indium oxide front electrodes

    OpenAIRE

    Battaglia, Corsin; Erni, Lukas; Boccard, Mathieu; Barraud, Loris; Escarre?, Jordi; So?derstro?m, Karin; Bugnon, Gre?gory; Billet, Adrian; Ding, Laura; Despeisse, Matthieu; Haug, Franz-josef; Wolf, Stefaan; Ballif, Christophe

    2011-01-01

    We investigate the performance of hydrogenated indium oxide as a transparent front electrode for micromorph thin-film silicon solar cells on glass. Light trapping is achieved by replicating the morphology of state-of-the-art zinc oxide electrodes, known for their outstanding light trapping properties, via ultraviolet nanoimprint lithography. As a result of the high electron mobility and excellent near-infrared transparency of hydrogenated indium oxide, the short-circuit current density of the...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Enhanced omni-directional performance of copper zinc tin sulfide thin film solar cell by gradient index coating

    Science.gov (United States)

    Ge, Zhongyang; Rajbhandari, Pravakar; Hu, Junjie; Emrani, Amin; Dhakal, Tara P.; Westgate, Charles; Klotzkin, David

    2014-03-01

    Many types of thin-film solar cells have a top, transparent conducting oxide (TCO) coating (such as aluminum-doped zinc oxide (AZO)) through which light is transmitted and current collected. In this paper, we demonstrate an effective antireflective coating for TCO surfaces using a gradient index coating formed from co-sputtered AZO and silicon dioxide (SiO2) targets that reduces reflection loss from the TCO. When applied to an active solar device, the power conversion efficiency of the solar cell increased by >10% when measured at normal incidence and >20% at angles 10° or greater.

  2. Double-layer indium doped zinc oxide for silicon thin-film solar cell prepared by ultrasonic spray pyrolysis

    International Nuclear Information System (INIS)

    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 6.82×10?3 ?·cm and particle grains. The double-layers structure is designed to fabricate the ZnO:In thin film with low resistivity (2.58×10?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)

  3. CdS quantum dots sensitized Cu doped ZnO nanostructured thin films for solar cell applications

    Science.gov (United States)

    Poornima, K.; Gopala Krishnan, K.; Lalitha, B.; Raja, M.

    2015-07-01

    ZnO nanorods and Cu doped ZnO nanorods thin films have been prepared by simple hydrothermal method. CdS quantum dots are sensitized with Cu doped ZnO nanorod thin films using successive ionic layer adsorption and reaction (SILAR) method. The X-ray diffraction study reveals that ZnO nanorods, and CdS quantum dot sensitized Cu doped ZnO nanorods exhibit hexagonal structure. The scanning electron microscope image shows the presence of ZnO nanorods. The average diameter and length of the aligned nanorod is 300 nm and 1.5 ?m respectively. The absorption spectra shows that the absorption edge of CdS quantum dot sensitized ZnO nanorod thin film is shifted toward longer wavelength region when compared to the absorption edge of ZnO nanorods film. The conversion efficiency of the CdS quantum dot sensitized Cu doped ZnO nanorod thin film solar cell is 1.5%.

  4. Characterization of Thin Films for Polymer Solar Cells : Stability and Response to Concentrated Light

    DEFF Research Database (Denmark)

    Tromholt, Thomas

    2012-01-01

    The field of polymer solar cells has undergone an extensive development in recent years after the invention of semiconducting polymers in 1991. Efficiencies have gradually increased to above 10 %, and high throughput processing methods such as roll-to-roll coating allow for production of thousands of solar cells with low embedded time, material, and energy consumption as compared to silicon solar cells. Consequently, different demonstration products of small mobile gadgets based on polymer solar cells have been produced, which are fully competitive with conventional energy technologies, illustrating the maturity of the technology. However, a limiting factor in terms of full commercialization is the stability of polymer solar cells. While is has been estimated that 10 years lifetime is needed, existing technologies only provide stabilities up to 1 year. Degradation of polymer solar cell is a 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 which the life time of the cell is highly increased. An alternative approach is to increase the photo stability of the cell components, and especially the light absorbing conjugated polymer has been subject to extensive attention. The photo stability of conjugated polymers varies by orders of magnitude from type to type depending on the chemical structure of the material and consequently, the lifetime is highly influenced by the polymer stability. Photochemical degradation of polymers, i.e. degradation of thin films of polymer in the ambient under light exposure, is a technique normally applied to evaluate polymer stabilities. Hereby, an extensive list of stabilities of different materials has been established providing an understanding of the stability of the individual building blocks of polymer. While being a highly practical tool, no rigorous reports on the photochemical degradation as a technique exist where the technique is validated and different pit-falls identified. Consequently, a rigorous study on the validation and maturing of this technique was performed during this PhD work (Chapter 2). Furthermore, as research gradually increases the lifetime of polymers to months or years, stability evaluations at standard degradation conditions become impractical. Accelerated degradation has been performed with heat and different gases by which the timeframe of stability evaluations have been reduced by up to a factor of 20. However, light, which appears at the most intuitive acceleration 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 was one of the main topics during this PhD, where the construction and development of light concentrators, both by sun light as well as artificial light, was given extensive attention. This resulted in three different light concentrators, a lens based solar concentrator, a mirror based solar concentrator, and an artificial light concentrator for indoor use (Chapter 3). With these concentration setups, acceleration factors of up to 1200 were obtained for degradation of typical conjugated polymers thus significantly reducing the timeframe of stability evaluations. The potential of this approach is that stability evaluation can become a routine characterization techniquefor novel conjugated polymers, when these are applied to polymer solar cells and their efficiencies are reported. By making the polymer stability practically accessible, development of polymer stability can become significantly more transparent and focused (Chapter 4). A direct alternative application of concentrated light is the application to polymer solar cells. Stabilities of polyme

  5. A pilot investigation on laser annealing for thin-film solar cells: Crystallinity and optical properties of laser-annealed CdTe thin films by using an 808-nm diode laser

    Science.gov (United States)

    Kim, Nam-Hoon; Park, Chan Il; Park, Jinseong

    2013-02-01

    Compared to conventional furnace and rapid thermal annealing, laser annealing for heterojunctioned thin-film solar cells has several advantages including excellent annealing selectivity to the under-layers with a localized high temperature for a short process time. A continuous wave 808-nm diode laser was used for the laser annealing process of CdTe thin films for various output powers. The grains in the laser-annealed CdTe thin films grew along the C (111), H (110), and C (311) planes. Laser annealing resulted in an increase in grain size and a decrease in surface roughness. The optical band gap energy of the CdTe thin films was affected directly by the grain size, showing 1.460 eV and 1.415 eV for the as-deposited and laser-annealed CdTe thin films, respectively. The absorbance of the CdTe thin films with better crystallinity showed an improved value of 99.5-99.9% in the visible spectral region after laser annealing at an output power of 0.91 W.

  6. Damp-Heat Induced Degradation of Transparent Conducting Oxides for Thin-Film Solar Cells: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Pern, F. J.; Noufi, R.; Li, X.; DeHart, C.; To, B.

    2008-05-01

    The stability of intrinsic and Al-doped single- and bi-layer ZnO for thin-film CuInGaSe2 solar cells, along with Al-doped Zn1-xMgxO alloy and Sn-doped In2O3 (ITO) and F-doped SnO2, was evaluated by direct exposure to damp heat (DH) at 85oC and 85% relative humidity. The results show that the DH-induced degradation rates followed the order of Al-doped ZnO and Zn1-xMgxO >> ITO > F:SnO2. The degradation rates of Al:ZnO were slower for films of higher thickness, higher substrate temperature in sputter-deposition, and with dry-out intervals. As inferred from the optical micro-imaging showing the initiation and propagation of degrading patterns and regions, the degradation behavior appears similar for all TCOs, despite the obvious difference in the degradation rate. A degradation mechanism is proposed to explain the temporal process involving thermal hydrolysis.

  7. Depth profile analysis of thin film solar cells using SNMS and SIMS

    Energy Technology Data Exchange (ETDEWEB)

    Gastel, M. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen; Breuer, U. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen; Holzbrecher, H. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen; Becker, J.S. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen; Dietze, H.J. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen; Wagner, H. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Schicht- und Ionentechnik

    1997-05-01

    SNMS (sputtered neutrals mass spectrometry) and SIMS (secondary ion mass spectrometry) are used for the depth profile analysis of thin film solar cells based on amorphous silicon. In order to enhance depth resolution, model systems are analyzed only representing parts of the layered system. Results concerning the TCO (transparent conducting oxide)/p interface and the n/i interface are presented. To minimize matrix effects, SNMS is used when the sample consists of layers with different matrices. Examples are the TCO/p interface (where the transition lengths of the depth profiles are found to be sharper when ZnO is used as TCO compared to SnO{sub 2}) and SnO{sub 2}/ZnO interfaces in coated TCO layers (where a Sn contamination inside the ZnO layer is found depending on the plasma pressure during the ZnO deposition). SIMS is used when the limits of detection reached by SNMS are not sufficient. Examples are H depth profiles in ZnO layers or P depth profiles near the n/i-interface. (orig.). With 6 figs.

  8. Photon confinement in high-efficiency, thin-film III-V solar cells obtained by epitaxial lift-off

    International Nuclear Information System (INIS)

    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 alrea 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

  9. Characterization of nanocrystalline SnO2 thin film fabricated by electrodeposition method for dye-sensitized solar cell application

    International Nuclear Information System (INIS)

    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 ?A/cm2, fill factor (FF = 0.4), photovoltage (Voc = 0.21 V) and overall conversion efficiency (?) 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.

  10. Co-electroplated Kesterite Bifacial Thin-Film Solar Cells: A Study of Sulfurization Temperature.

    Science.gov (United States)

    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

  11. Characterization of Optic Properties ZnO:Al Thin Film on Glass Substrate for Solar Cell Window

    International Nuclear Information System (INIS)

    It has been characterized a ZnO:Al thin film growth using sputtering technique for solar cell window. The aims of this research is to get a ZnO:Al thin film that can be used as a TCO (Transparent Conducting Oxide) on amorphous silicon solar cell. To get an optimum properties, deposition process has been done for various parameters, such as composition/concentration of Al, substrate temperature, gas pressure and deposition time. Based on experiments result, it is found that the optimum result was achieved at temperature 450 oC, gas pressure 6 x 10 -2 torr and time 1.5 hours. From optical properties (transmittance) measurements using UV-vis, it was found that the optimum results was achieved at temperature 450 oC. At this conditions, wave length (500 - 800) nm, the transmittance was (50 - 82) %, at pressure 6 x 10 -2 torr the transmittance was (50 - 80) % and at deposition time 1.5 hours was (49 - 81) %. For ZnO thin film, was at wave length (500 - 800) nm, the transmittance was (78 - 80) %. From micro structure analysis using SEM, it was found that the thickness layer of ZnO was 1.5 ?m and 1.3 ?m for ZnO: Al. While from surface morphology it was found that for ZnO thin layer the grains was distributed homogeneously, while for ZnO: Al the grains was distributed unhomogeneously. (author)

  12. Further investigations in optical confinement and solar cell processing for crystalline silicon thin film solar cells

    OpenAIRE

    Lindekugel, S.; Mitchell, E. J.; Ku?nle, M.; Janz, S.; Reber, S.

    2009-01-01

    This paper presents the investigations in the performance of different SiC and SiO2 intermediate layer (IL) configurations during a zone melting recrystallisation (ZMR) step. The goal is to implement an IL consisting of an electrically conductive all-SiC multilayer stack in Recrystallised Wafer Equivalents (RexWE) solar cells. We tested stoichiometric SiC layers, carbon rich SiC layers and silicon rich SiC layers embedded in SiO2 layers, temperature pretreatments and several multilayer system...

  13. Combined model of non-conformal layer growth for accurate optical simulation of thin-film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Copper oxide thin film and nanowire as a barrier in ZnO dye-sensitized solar cells

    International Nuclear Information System (INIS)

    The ZnO dye-sensitized solar cells (DSSCs) with different photoelectrodes were studied on the effect of CuO layer as a barrier layer toward power conversion characteristics. The structures of DSSCs based on ZnO as a photoelectrode, Eosin-Y as a dye sensitizer, iodine/iodide solution as an electrolyte and Pt/FTO as a counterelectrode. CuO powder, nanowire prepared by oxidation reaction of copper powder and CuO thin film prepared by evaporation copper thin film, were used as a layer on the top of ZnO layer to form blocking layer. The photocurrent, photovoltage and power conversion efficiency characteristics for DSSCs were measured under illumination of simulated sunlight obtained from a solar simulator with the radiant power of 100 mW/cm2. It was found that ZnO DSSCs with CuO thin film exhibited highest current density of 5.10 mA/cm2 and highest power conversion efficiency of 0.92% than those of CuO powder and nanowire. The enhancement of the power conversion efficiency can be explained in terms of the retardation of the interfacial recombination dynamics of CuO blocking layer.

  15. In situ silicon oxide based intermediate reflector for thin-film silicon micromorph solar cells

    OpenAIRE

    Buehlmann, Peter; Bailat, J.; Domine?, Didier; Billet, Adrian; Meillaud, F.; Feltrin, Andrea; Ballif, Christophe

    2008-01-01

    We show that SiO-based intermediate reflectors (SOIRs) can be fabricated in the same reactor and with the same process gases as used for thin-film silicon solar cells. By varying input gas ratios, SOIR layers with a wide range of optical and electrical properties are obtained. The influence of the SOIR thickness in the micromorph cell is studied and current gain and losses are discussed. Initial micromorph cell efficiency of 12.2% (Voc=1.40 V, fill factor=71.9%, and Jsc=12.1 mA/cm2) is achiev...

  16. Electronic grain boundary properties in polycrystalline Cu(In,Ga)Se{sub 2} semiconductors for thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    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 ?3 GBs have a lower probability to possess a charged potential barrier than lower symmetric non-?3 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 ?3, could help to explain the large variations of potential barriers observed at GBs in polycrystalline CIGSe thin films.

  17. Characterization of deep defects in CdS/CdTe thin film solar cells using deep level transient spectroscopy

    International Nuclear Information System (INIS)

    The presence of deep defects in CdS/CdTe thin film solar cells strongly affects the electrical properties and as a result the performance of the cells. Therefore, it is desirable to understand the role of these defect states. This paper describes the detection of electron traps in CdS/CdTe thin film solar cells using deep level transient spectroscopy. Two series of samples with a different activation step (activation in air vs. activation in vacuum) are compared. Electrical injection DLTS uses an electrical pulse to inject electrons in the CdTe. This way a new electron trap could be characterized at 0.44 eV below conduction band in the air activated cells. Optical DLTS uses an optical laser pulse (?=635 nm) to create minority carriers. In this case minority traps are found in both kinds of samples. In the air activated cells two closely spaced defects are detected (0.44 and 0.42 eV below conduction band) with concentrations of a few percent of the background concentration. In the vacuum activated cells a broad band is detected. However, not fully characterized, it is located at approximately 0.4 eV below conduction band. Using the DLTS results, simulations were performed to explain the forward J-V-characteristics of the solar cells. These simulations are in close agreement with the experimental results if the concentrations of the deep traps are taken sufficiently high

  18. Scattering matrix analysis for evaluating the photocurrent in hydrogenated-amorphous-silicon-based thin film solar cells.

    Science.gov (United States)

    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

  19. Determination of the optical constants and dielectric functions of thin film a-Si : H solar cell layers

    Energy Technology Data Exchange (ETDEWEB)

    Stutenbaeumer, Ulrich; Mesfin, Belayneh; Beneberu, Solomon [Department of Physics, Addis Ababa University, PO Box 1176, Addis Ababa (Ethiopia)

    1999-02-22

    The transmittance spectra of thin film a-Si : H p-i-n solar cells and a combination of different layers were measured in the visible and near-infrared spectral regions. With the help of computer assisted optical spectroscopy, the spectra were analysed and the optical constants of the different layers of the layer stack systems were determined. The index of refraction, the energy gap, the layer thickness and the complex dielectric functions of the p- and n-doped layers and the intrinsic a-Si : H layer were calculated with the Forouhi and Bloomer model. This method allows a very fast and accurate optical characterisation of photovoltaic cells

  20. Sulfur-doped nickel oxide thin film as an alternative to Pt for dye-sensitized solar cell counter electrodes

    Energy Technology Data Exchange (ETDEWEB)

    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)

  1. Preparation and characterization of CuInSe2 particles via the hydrothermal route for thin-film solar cells

    International Nuclear Information System (INIS)

    Highlights: ? A new hydrothermal process for preparing copper indium diselenide (CuInSe2). ? Well-crystallized CuInSe2 particles are obtained at 180 deg. C for 1 h. ? Densified CuInSe2 thin films are prepared from ink printing. ? Increasing temperatures result in an improvement of properties of CuInSe2 films. - Abstract: CuInSe2 powders with a chalcopyrite structure used in thin-film solar cells were successfully prepared via a hydrothermal method at low temperatures within short durations. Well-crystallized CuInSe2 particles were formed via the hydrothermal reaction at 180 deg. C for 1 h. The concentrations of stabilizer, triethanolamine (TEA), significantly affected the purity, morphology and particle sizes of the prepared powders. Increasing the reaction duration and temperatures led to decrease the amount of second phase In(OH)3 and resulted in the formation of pure CuInSe2. Densified CuInSe2 thin films were prepared from ink printing with the addition of the flux. Increasing the selenization temperatures increased the grain size and improved the crystallinity of CuInSe2 films.

  2. Opto-electronic properties of rough LP-CVD ZnO:B for use as TCO in thin-film silicon solar cells

    International Nuclear Information System (INIS)

    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%

  3. Radial n-i-p structure SiNW-based microcrystalline silicon thin-film solar cells on flexible stainless steel

    OpenAIRE

    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 ...

  4. Impact of contamination on hydrogenated amorphous silicon thin films and solar cells

    Energy Technology Data Exchange (ETDEWEB)

    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 c

  5. ZnO thin films fabricated by chemical bath deposition, used as buffer layer in organic solar cells

    International Nuclear Information System (INIS)

    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.

  6. A comparative study of solution-processed low- and high-band-gap chalcopyrite thin-film solar cells

    International Nuclear Information System (INIS)

    Low-cost and printable chalcopyrite thin-film solar cells were fabricated by a precursor solution-based coating method with a multi-step heat-treatment process (oxidation, sulfurization, and selenization). The high-band-gap (1.57 eV) Cu(InxGa1?x)S2 (CIGS) solar cell showed a high open-circuit voltage of 787 mV, whereas the low-band-gap (1.12 eV) Cu(InxGa1?x)(S1?ySey)2 (CIGSSe) cell exhibited a high short-circuit current density of 32.6 mA cm?2. The energy conversion efficiencies were 8.28% for CIGS and 8.81% for CIGSSe under standard irradiation conditions. Despite similar efficiencies, the two samples showed notable differences in grain size, surface morphology, and interfacial properties. Low-temperature transport and admittance characteristics of the samples clearly revealed how their structural differences influenced their photovoltaic and electrical properties. Such analyses provide insight into the enhanced solar cell performance of the solution-processed chalcopyrite thin films. (paper)

  7. A comparative study on the performance of Kesterite based thin film solar cells using SCAPS simulation program

    Science.gov (United States)

    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.

  8. Absorptive carbon nanotube electrodes: Consequences of optical interference loss in thin film solar cells

    Science.gov (United States)

    Tait, Jeffrey G.; de Volder, Michaël F. L.; Cheyns, David; Heremans, Paul; Rand, Barry P.

    2015-04-01

    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 ? ?-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.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 ? ?-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. Electronic supplementary information (ESI) available: An animation of the MWCNT spray coating process, and five figures, including: a photograph of completed devices with MWCNT electrodes, performance metrics for devices with photoactive layer thickness up to 3000 nm, contour plots of simulated devices used to build Fig. 5, simulation data for perovskite devices, and a contour plot of the simplified equation of photoactive layer thickness required to attain a specified photocurrent ratio (x-axis) and absorption coefficient (y-axis). See DOI: 10.1039/c5nr01119a

  9. Dipolar and Quadrupolar Modes of SiO2/Au Nanoshell Enhanced Light Trapping in Thin Film Solar Cells

    International Nuclear Information System (INIS)

    Dipolar and quadrupolar resonance wavelengths of SiO2/Au nanoshell surface plasmons are designed at 560 nm to enhance the light trapping in thin film solar cells. In order to quantitatively describe the light trapping effect, the forward-scattering efficiency (FSE) and the light trapping efficiency (LTE) are proposed by considering the light scattering direction of SiO2/Au nanoshells. Based on the Mie theory, the FSE and the LTE are calculated for SiO2/Au nanoshells of different dimensions, and the contributions of the dipolar and quadrupolar modes to the light trapping effect are analyzed in detail. When the surface coverage of nanoshells is 5%, the LTEs are 21.7% and 46.9% for SiO2/Au nanoshells with sizes of (31 nm, 69 nm) and (53 nm, 141 nm), respectively. The results indicate that the SiO2/Au nanoshell whose quadrupolar mode peak is designed to the strongest solar energy flux density of the solar spectrum facilitates the further enhancement of light harvesting in thin film solar cells. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  10. Light coupling into the Whispering Gallery Modes of a fiber array thin film solar cell for fixed partial Sun tracking

    Science.gov (United States)

    Mariano, Marina; Rodríguez, Francisco J.; Romero-Gomez, Pablo; Kozyreff, Gregory; Martorell, Jordi

    2014-01-01

    We propose the use of whispering gallery mode coupling in a novel configuration based on implementing a thin film cell on the backside of an array of parallel fibers. We performed numerical calculations using the parameters of a thin film organic cell which demonstrate that light coupling becomes more effective as the angle for the incident light relative to the fiber array normal increases up to an optimal angle close to 55?deg. At this angle the power conversion efficiency of the fiber array solar cell we propose becomes 30% times larger than the one from an equivalent planar cell configuration. We demonstrate that the micro fiber array solar cell we propose may perform an effective partial tracking of the sun movement for over 100?degrees without any mechanical help. In addition, in the event that such fiber array cell would be installed with the adequate orientation on a vertical façade, an optimal photon-to-charge conversion would be reached for sunlight incident at 55?deg with respect to the horizon line, very close to the yearly average position for the sun at Latitude of 40?deg.

  11. Simulation of nanostructure-based and ultra-thin film solar cell devices beyond the classical picture

    CERN Document Server

    Aeberhard, Urs

    2014-01-01

    In this paper, an optoelectronic device simulation framework valid for arbitrary spatial variation of electronic potentials and optical modes, and for transport regimes ranging from ballistic to diffusive, is used to study non-local photon absorption, photocurrent generation and carrier extraction in ultra-thin film and nanostructure-based solar cell devices at the radiative limit. Among the effects that are revealed by the microscopic approach and which are inaccessible to macroscopic models is the impact of structure, doping or bias induced nanoscale potential variations on the local photogeneration rate and the photocarrier transport regime.

  12. ZnO nanorod arrays for highly efficient thin film a-Si and micromorph solar cells.

    Czech Academy of Sciences Publication Activity Database

    Neykova, Neda; Hruška, Karel; Remeš, Zden?k; Van??ek, 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 ?R(CZ) GAP108/11/0937 Grant ostatní: FP7(XE) CP-IP 214134-2 Institutional research plan: CEZ:AV0Z10100521 Keywords : ZnO nanocolumns * thin film solar cells * EBL Subject RIV: BM - Solid Matter Physics ; Magnetism

  13. Natural Sensitizer for Dye-Sensitized Solar Cells Using Three Layers of Photoelectrode Thin Films with a Schottky Barrier

    OpenAIRE

    Ho Chang; Mu-Jung Kao; Tien-Li Chen; Hin-Guo Kuo; Kun-Ching Choand; Xiu-Ping Lin

    2011-01-01

    Problem statement: This study combines Au nanoparticles with TiO2 nanoparticles to form a Schottky barrier and applies it to the photo electrode thin film of Dye-Sensitized Solar Cells (DSSCs). Approach: First, commercial TiO2 powder (Degussa P25) was put into the alkaline solution to prepare TiO nano tubes (Tnt) by a hydrothermal process. Tnt were sintered at 550° to obtain TntC550 particles and fabricated into a translucent sol by two hydrothermal treatments and ...

  14. Light trapping efficiency of periodic and quasiperiodic back-reflectors for thin film solar cells: A comparative study

    Science.gov (United States)

    Micco, A.; Ricciardi, A.; Pisco, M.; La Ferrara, V.; Mercaldo, L. V.; Delli Veneri, P.; Cutolo, A.; Cusano, A.

    2013-08-01

    Recently, great efforts have been carried out to design optimized metallic nano-grating back-reflectors to improve the light absorption in thin film solar cells. In this work, we compare the performances of deterministic aperiodic backreflectors in the form of 1-D nanogratings based on the generalized Fibonacci deterministic aperiodic sequence with a standard periodic one. The case of study here analyzed relies on a realistic solar cell model, where light absorption is evaluated only in the intrinsic region of an amorphous silicon P-I-N junction. We found that the results of comparison are strongly influenced by the amorphous silicon extinction coefficient within the near-infrared wavelength range, where most photonic-plasmonic modes (responsible for the light absorption enhancement typically observed when structured metal nanogratings are employed) are excited. In particular, with device-grade hydrogenated amorphous silicon, we demonstrate that Fibonacci-like backreflectors are able to provide an absorption enhancement of about 4% and 20% with respect to periodic and flat metallic backreflectors, respectively. We also found that aperiodic gratings guarantee better results in terms of robustness to the incident angle of the incoming radiation. Overall, our results confirm that aperiodic geometries are effectively able to offer some intriguing perspectives to enhance light trapping capability in thin film solar cells especially thanks to the large set of patterns employable to enable a proper design of resonant modes number and their spectral locations.

  15. New strategies in laser processing of TCOs for light management improvement in thin-film silicon solar cells

    Science.gov (United States)

    Lauzurica, S.; Lluscà, M.; Canteli, D.; Sánchez-Aniorte, M. I.; López-Vidrier, J.; Hernández, S.; Bertomeu, J.; Molpeceres, C.

    2014-10-01

    Light confinement strategies play a crucial role in the performance of thin-film (TF) silicon solar cells. One way to reduce the optical losses is the texturing of the transparent conductive oxide (TCO) that acts as the front contact. Other losses arise from the mismatch between the incident light spectrum and the spectral properties of the absorbent material that imply that low energy photons (below the bandgap value) are not absorbed, and therefore can not generate photocurrent. Up-conversion techniques, in which two sub-bandgap photons are combined to give one photon with a better matching with the bandgap, were proposed to overcome this problem. In particular, this work studies two strategies to improve light management in thin film silicon solar cells using laser technology. The first one addresses the problem of TCO surface texturing using fully commercial fast and ultrafast solid state laser sources. Aluminum doped Zinc Oxide (AZO) samples were laser processed and the results were optically evaluated by measuring the haze factor of the treated samples. As a second strategy, laser annealing experiments of TCOs doped with rare earth ions are presented as a potential process to produce layers with up-conversion properties, opening the possibility of its potential use in high efficiency solar cells.

  16. Interface characteristics of CdS/Cu(In,Ga)Se2 thin-film solar cells by using photoreflectance spectroscopy

    International Nuclear Information System (INIS)

    We investigated the CdS/Cu(In,Ga)Se2 interface characteristics of Cu(In,Ga)Se2 (CIGS) thin film solar cells by using photoreflectance spectroscopy and their influence on the photovoltaic performance. We prepared CIGS solar cells with CdS and CIGS layers fabricated by using different methods of chemical bath deposition (CBD). The thiourea concentration in the CBD-CdS process was varied from 0.025 M to 0.1 M. The final In-Ga-Se deposition time for the CIGS film's deposition was varied from 300 s to 490 s. We fabricated solar cells with thin films fabricated by using a combination of these conditions. The transition energies changed from 2.277 eV to 2.387 eV and the conversion efficiencies changed from 14.13% to 15.81% depending on the fabrication process. The formation of different states in CdS/CIGS resulted in different conversion efficiencies, as well as different band alignments at the CdS/CIGS interface.

  17. Plasmonic back contacts with non-ordered Ag nanostructures for light trapping in thin-film silicon solar cells

    International Nuclear Information System (INIS)

    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 light–matter 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

  18. Plasmonic back contacts with non-ordered Ag nanostructures for light trapping in thin-film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    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 light–matter 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.

  19. Synthesis and characterization of Zn(O,OH)S and AgInS2 layers to be used in thin film solar cells

    International Nuclear Information System (INIS)

    In this paper AgInS2 and Zn(O,OH)S thin films were synthesized and characterized. AgInS2 layers were grown by co-evaporation from metal precursors in a two-step process, and, Zn(O,OH)S thin films were deposited from chemical bath containing thiourea, zinc acetate, sodium citrate and ammonia. X-ray diffraction measurements indicated that AgInS2 thin films grown with chalcopyrite structure, and the as-grown Zn(O,OH)S thin films were polycrystalline. It was also found that the AgInS2 films presented p-type conductivity, a high absorption coefficient (greater than 104 cm-1) and energy band-gap Eg of about 1.95 eV, Zn(O,OH),S thin films presented Eg of about 3.89 eV. Morphological analysis showed that under this synthesis conditions Zn(O,OH),S thin films coated uniformly the absorber layer. Additionally, the Zn(O,OH)S kinetic growth on AgInS2 layer was studied also. Finally, the results suggest that these layers possibly could be used in one-junction solar cells and/or as top cell in a tandem solar cell.

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

    DEFF Research Database (Denmark)

    Soppe, W.; Haug, F.-J.

    2011-01-01

    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/ c-Si tandem cells with more than 11% efficiency.

  1. Severe test of a dangling bond only model of thin film silicon p-i-n solar cell degradation

    International Nuclear Information System (INIS)

    This paper uses a model that links previous research into the metastable defects found in undoped thin film Si:H or a-Si:H (TFS) films to the light-induced degradation of TFS solar cells. The fill factor changes of two experimental studies are modeled. The first series is a group of 704, 4-cm2 p-i-n solar cells with eleven different i-layer thicknesses ranging from 1000A to 200,000A. The second series is a group of 144, 4-cm2 p-i-n solar cells all made in the same deposition and then exposed under different illumination levels and temperatures. The dangling bond model is shown to be an incomplete explanation of the fill factor changes due to light soaking. Data for the short time region and long time region cannot both be fit with the same parameters

  2. Fabrication of polycrystalline CdTe thin-film solar cells using carbon electrodes with carbon nanotubes

    Science.gov (United States)

    Okamoto, Tamotsu; Hayashi, Ryoji; Ogawa, Yohei; Hosono, Aikyo; Doi, Makoto

    2015-04-01

    The effects of adding carbon nanotubes (CNTs) to carbon back electrodes in polycrystalline CdTe thin-film solar cells were investigated. The CNTs were prepared by arc discharge under atmospheric pressure. The conductivity of the obtained CNT film with a density of 1.65 g/cm3 was approximately 2.6 × 103 S/cm. In the CdTe solar cells using carbon back electrodes with CNTs, the fill factor (FF) was improved as a result of adding CNTs with a concentration of 1 to 5 wt %. The improvement of FF was mainly due to the decrease in the series resistance of the CdTe solar cell. Furthermore, the open-circuit voltage (VOC) was improved by the CNT addition. The improvement of VOC was probably due to the reduction of the back barrier at the back contact.

  3. Optical properties of Cd1-xZnxS thin films for CuInGaSe2 solar cell application

    International Nuclear Information System (INIS)

    The photovoltaic Cd1-xZnxS thin films, fabricated by chemical bath deposition, were successfully used as n-type buffer layer in CuInGaSe2 (CIGS) solar cells. Comprehensive optical properties of the Cd1-xZnxS thin films were measured and modeled by spectroscopic ellipsometry (SE), which is proven to be an excellent and non-destructive technique to determine optical properties of thin films. The optical band gap of Cd1-xZnxS thin films can be tuned from 2.43 eV to 3.25 eV by controlling the Zn content (x) and deposition conditions. The wider-band-gap Cd1-xZnxS film was found to be favorable to improve the quantum efficiency in the wavelength range of 450-550 nm, resulting in an increase of short-circuits current for solar cells. From the characterization of quantum efficiency (QE) and current-voltage curve (J-V) of CIGS cells, the Cd1-xZnxS films (x = 0.32, 0.45) were demonstrated to significantly enhance the photovoltaic performance of CIGS solar cell. The highest efficiency (10.5%) of CIGS solar cell was obtained using a dense and homogenous Cd0.68Zn0.32S thin film as the buffer layer.

  4. Modified co-evaporation process for fabrication of 4 cm × 4 cm large area flexible CIGS thin film solar cells on polyimide substrate

    Science.gov (United States)

    Li, Zhiguo; Liu, Yiming; Liu, Wei; Li, Zuliang; Cheng, Long; Qin, Xiaotong; Li, Xiaodong; Zhou, Zhiqiang; Zhang, Yi; He, Qing; Sun, Yun

    2015-04-01

    A modified three-stage co-evaporation process has been studied in our work for the fabrication of large area Cu(In,Ga)Se2 (CIGS) thin-film solar cells on flexible polyimide substrates. According to our results, the open circuit voltage and fill factor are improved significantly by using the modified process. In order to quantitatively analyze the effects of the modified band-gap gradient in CIGS thin film, a modeling investigation is carried out by employing a simulation program, wxAMPS. The simulation indicates that the device improvement is not only attributed to the refined Ga gradient profile, but also to the better crystalline quality. The elemental evaporation rates and the content of Cu are found to be key factors for the large-area solar cell preparation. Finally, 16 cm2 CIGS thin-film solar cells on PI substrates are fabricated, and the highest cell efficiency has achieved 7%.

  5. Analysis of radiation resistance of InGaP/GaAs dual-junction thin-film space solar cell

    International Nuclear Information System (INIS)

    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)

  6. Structural and optical properties of electrodeposited culnSe2 thin films for photovoltaic solar cells

    International Nuclear Information System (INIS)

    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

  7. Deep level transient spectroscopy investigation of deep levels in CdS/CdTe thin film solar cells with Te:Cu back contact

    International Nuclear Information System (INIS)

    Deep levels in Cds/CdTe thin film solar cells have a potent influence on the electrical property of these devices. As an essential layer in the solar cell device structure, back contact is believed to induce some deep defects in the CdTe thin film. With the help of deep level transient spectroscopy (DLTS), we study the deep levels in CdS/CdTe thin film solar cells with Te:Cu back contact. One hole trap and one electron trap are observed. The hole trap H1, localized at Ev + 0.128 eV, originates from the vacancy of Cd (VCd). The electron trap E1, found at Ec ?0.178 eV, is considered to be correlated with the interstitial Cuj+ in CdTe. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  8. Characterization of CdS Thin-Film in High Efficient CdS/CdTe Solar Cells

    Science.gov (United States)

    Tsuji, Miwa; Aramoto, Tetsuya; Ohyama, Hideaki; Hibino, Takeshi; Omura, Kuniyoshi

    2000-07-01

    Cadmium sulfide (CdS) thin films are the most commonly used window materials for high efficient cadmium telluride (CdTe) and chalcopyrite polycrystalline thin-film photovoltaic devices. High efficient CdS/CdTe solar cells with thin CdS films have been developed using ultrathin CdS films with a thickness of less than 0.1 ?m. CdS films were deposited on transparent conductive oxide (TCO)/glass substrates by the metal organic chemical vapor deposition (MOCVD) technique. CdTe films were subsequently deposited by the close-spaced sublimation (CSS) technique. The screen printing and sintering method fabricated carbon and silver electrodes. Cell performance depends primarily on the electrical and optical properties of CdS films. Therefore we started to develop higher-quality CdS films and found clear differences between high- and low-quality CdS films from the analyses of scanning electron microscope (SEM), atomic force microscope (AFM), secondary ion mass spectroscopy (SIMS), thermal desorption spectrometry (TDS) and Fourier transforms-infrared spectrometry (FT-IR) measurements. As a result of controlling the quality of CdS films, a photovoltaic conversion efficiency of 10.5% has been achieved for size of 1376 cm2 of the solar cells under the Air Mass (AM) 1.5 conditions of the Japan Quality Assurance Organization.

  9. Thin film silicon solar cells and modules: From R and D Lab developments to large-area production tools

    Energy Technology Data Exchange (ETDEWEB)

    Kroll, Ulrich [Oerlikon Solar-Lab SA, Neuchatel (Switzerland)

    2009-07-01

    Up-scaling of thin film silicon solar cells to industrial commercial products of 1 m{sub 2} module area is a highly challenging task. Hereby, the transfer of high efficiency device results obtained in small area research-type equipments to large area high performance R and D and high productivity mass fabrication equipment are important issues needed to be solved. Especially the PECVD (Plasma Enhanced Chemical Vapor Deposition) equipment in the thin film production line is one of the most important key elements to bring the module efficiency up and to reduce manufacturing costs. In a first step, deposition processes are developed and optimized in smaller R and D KAI systems. These process parameters are then transferred to industrial size reactors of 1.4 m{sub 2}. Following this strategy we achieved recently amorphous silicon p-i-n single-junction and Micromorph (amorphous/ microcrystalline silicon) tandem junction 1.4 m{sub 2} R and D solar modules with initial aperture module efficiencies of 9.63% respectively of 9.6 %. These remarkable efficiencies clearly demonstrate the high potential of our PECVD systems. Based on these results, Oerlikon Solar as an equipment manufacturer is installing production facilities for amorphous silicon and Micromorph PV modules in the range well above several 100 MW capacities for all its customers worldwide.

  10. Influence of oblique-angle sputtered transparent conducting oxides on performance of Si-based thin film solar cells

    International Nuclear Information System (INIS)

    The transparent conducting oxide (TCO) films with low-refractive-index (low-n) are fabricated by the oblique-angle sputtering method. By using the experimentally measured physical data of the fabricated low-n TCO films as the simulation parameters, the effect of low-n TCOs on the performance of a-Si:H/?c-Si:H tandem thin film solar cells is investigated using Silvaco ATLAS. The Al-doped zinc oxide, indium tin oxide (ITO), and Sb-doped tin oxide films are deposited at the flux incidence angles of ?i = 0 (normal sputtering) and ?i = 80 from the sputtering target during the sputtering process. The oblique-angle sputtered films at ?i = 80 show the inclined columnar nanostructures compared to those at ?i = 0 , modifying the optical properties of the films. This is caused mainly by the increase of porosity within the film which leads to its low-n characteristics. The a-Si:H/?c-Si:H tandem thin film solar cell incorporated with the low-n ITO film exhibits an improvement in the conversion efficiency of ?1% under AM1.5g illumination because of its higher transmittance and lower absorption compared to that with the ITO film at ?i = 0 , indicating a conversion efficiency of 13.75%. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Characterization of CdS thin film in high efficient CdS/CdTe solar cells

    Science.gov (United States)

    Tsuji, Miwa; Aramoto, Tetsuya; Ohyama, Hideaki; Hibino, Takeshi; Omura, Kuniyoshi

    2000-06-01

    Cadmium sulfide (CdS) thin film is the most commonly used window material for high-efficient cadmium telluride (CdTe) thin-film photovoltaic devices. High-efficient CdS/CdTe solar cells have been developed using ultra-thin CdS films having a thickness of below 0.1 ?m. CdS film is deposited on transparent conductive oxide (TCO) film coated glass substrates by the metal organic chemical vapor deposition (MOCVD) technique, CdTe film is subsequently deposited by the close-spaced sublimation (CSS) technique. Finally, carbon and Ag-In electrodes are fabricated by the screen printing and sintering method. Cell performance depends primarily on the electrical and optical properties of CdS film, and hence we started to develop higher quality CdS film and found out clear differences between high- and low-quality CdS films from various analyses: SEM, AFM, SIMS, TDS and FT-IR. As a result of controlling qualities of CdS films, photovoltaic conversion efficiency of 10.5% has been achieved for a size of 1376 cm 2 of the solar module under air mass (AM) 1.5 conditions by the Japan Quality Assurance Organization (JQA).

  12. Development of thin film amorphous silicon oxide/microcrystalline silicon double-junction solar cells and their temperature dependence

    Energy Technology Data Exchange (ETDEWEB)

    Sriprapha, K.; Piromjit, C.; Limmanee, A.; Sritharathikhun, J. [Institute of Solar Energy Technology Development (SOLARTEC), National Science and Technology Development Agency (NSTDA), 111 Thailand Science Park, Phahonyothin Road, Klong 1, Klong Luang, Pathumthani 12120 (Thailand)

    2011-01-15

    We have developed thin film silicon double-junction solar cells by using micromorph structure. Wide bandgap hydrogenated amorphous silicon oxide (a-SiO:H) film was used as an absorber layer of top cell in order to obtain solar cells with high open circuit voltage (V{sub oc}), which are attractive for the use in high temperature environment. All p, i and n layers were deposited on transparent conductive oxide (TCO) coated glass substrate by a 60 MHz-very-high-frequency plasma enhanced chemical vapor deposition (VHF-PECVD) technique. The p-i-n-p-i-n double-junction solar cells were fabricated by varying the CO{sub 2} and H{sub 2} flow rate of i top layer in order to obtain the wide bandgap with good quality material, which deposited near the phase boundary between a-SiO:H and hydrogenated microcrystalline silicon oxide ({mu}c-SiO:H), where the high V{sub oc} can be expected. The typical a-SiO:H/{mu}c-Si:H solar cell showed the highest initial cell efficiency of 10.5%. The temperature coefficient (TC) of solar cells indicated that the values of TC for conversion efficiency ({eta}) of the double-junction solar cells were inversely proportional to the initial V{sub oc}, which corresponds to the bandgap of the top cells. The TC for {eta} of typical a-SiO:H/{mu}c-Si:H was -0.32%/ C, lower than the value of conventional a-Si:H/{mu}c-Si:H solar cell. Both the a-SiO:H/{mu}c-Si:H solar cell and the conventional solar cell showed the same light induced degradation ratio of about 20%. We concluded that the solar cells using wide bandgap a-SiO:H film in the top cells are promising for the use in high temperature regions. (author)

  13. Broadband grating couplers for efficient thin film solar cells. Final report; Breitband-Gitterkoppler fuer effiziente Duennschichtsolarzellen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Stutzmann, M.; Nebel, C.E.; Eisele, C.; Klein, S.; Carius, R.; Finger, F.; Schubert, M.

    2002-08-01

    Efficient thin film solar cells usually require a dedicated light trapping strategy in order to achieve an optimum absorption of the solar spectrum. At present, mainly statistically textured transparent conducting electrodes are used for this purpose (TCO layers, e.g. ZnO). One aim of this project was the preparation and characterization of microstructured periodic grating couplers for the efficient trapping of weakly absorbed light in silicon thin film cells. In addition, a preliminary investigation concerning the feasibility of thin SiGe-alloy films on glass as an alternative absorber layer for tandem solar cells was to be performed. Periodically structured TCO electrodes were prepared by holographic laser patterning. These electrode layers are transparent up to the UV spectral range and can be easily structured into sub-micron gratings using HCl etching. In cooperation with the Institute for Photovoltaics (IPV), the resulting light trapping structures were overgrown by amorphous silicon solar cells using PECVD. The electrical and optical properties of these solar cells with integrated grating couplers were investigated in a systematic way, with special emphasis on the possible enhancement of the internal electric field caused by the microstructure. In addition, the growth of amorphous and microcrystalline silicon solar cell structures by hot wire CVD on both, structured as well as unstructured substrates was studied at the IPV. A second part of the project was concerned with the deposition of ultrapure amorphous Si, SiGe, and Ge films on glass by evaporation in an ultra high vacuum, followed by laser recrystallization and hydrogen passivation. For this purpose, a dedicated UHV deposition system was built. The deposited films were recrystallized with a variety of different laser techniques in order to achieve a first optimization of crystallite sizes and electronic properties. Main results of the project: (i) Grating couplers indeed can provide an efficient and tunable means of coupling sunlight into thin film solar cells. While the best results achieved so far do not give rise to a noticeable improvement compared to light trapping strategies based on statistical texture, the transferability of the process developed here to other solar cell structures is an important advantage. (ii) Thin microcrystalline SiGe-layers on glass produced by evaporation and laser crystallization exhibit promising electronic and optical properties with respect to applications as absorber layers in thin film solar cells. However, to this end, a further optimization of the crystallization process and the ensuing material properties will be necessary. (orig.) [German] Fuer Duennschicht-Solarzellen ist im Allgemeinen eine integrierte Lichtfallenstruktur notwendig, um eine moeglichst vollstaendige Absorption des Sonnenspektrums zu erzielen. Gegenwaertig werden hierfuer fast ausschliesslich statistisch texturierte transparente Elektrodenschichten (z.B. aus ZnO) eingesetzt. Ziel dieses Projektes war die Herstellung und Untersuchung mikrostrukturierter periodischer Gitterkoppler zur gezielten Einkopplung schwach absorbierten Lichtes. Zusaetzlich sollten erste Versuche zum Einsatz von kristallinen SiGe-Duennschicht-Filmen auf Glas als stark absorbierendes Halbleitermaterial fuer den Einsatz in Tandem-Solarzellen exploratorisch durchgefuehrt werden. Im Rahmen des Forschungsprojektes wurden strukturierte Elektroden aus TCO hergestellt, die hohe optische Transparenz bis ins UV aufweisen. Zur effizienten Lichteinkopplung wurden erfolgreich Beugungsgitter im Submikrometerbereich hergestellt, die als Lichtfallen wirken. In Zusammenarbeit mit dem Institut fuer Photovoltaik (IPV) wurden diese Lichtfallen in Solarzellen integriert. Die elektrischen und optischen Eigenschaften dieser Solarzellen mit Gitterkoppler-Strukturen wurden systematisch untersucht, insbesondere auch hinsichtlich einer durch die Strukturierung bewirkten internen Feldverstaerkung. Zusaetzlich wurden am Institut fuer Photovoltaik des Forschungszentrums Juelich grundlagenorientierte Untersu

  14. Multilayer nanoparticle arrays for broad spectrum absorption enhancement in thin film solar cells

    CERN Document Server

    Krishnan, Aravind; Krishna, Siva Rama; Khan, Mohammed Zafar Ali

    2013-01-01

    In this paper, we present a theoretical study on the absorption efficiency enhancement of a thin film amorphous Silicon (a-Si) photovoltaic cell over a broad spectrum of wavelengths using multiple nanoparticle arrays. The light absorption efficiency is enhanced in the lower wavelengths by a nanoparticle array on the surface and in the higher wavelengths by another nanoparticle array embedded in the active region. The efficiency at intermediate wavelengths is enhanced by the constructive interference of plasmon coupled light. We optimize this design by tuning the radius of particles in both arrays, the period of the array and the distance between the two arrays. The optimization results in 61.44% increase in total quantum efficiency for a 500 nm thick a-Si substrate.

  15. Development of natively textured surface hydrogenated Ga-doped ZnO-TCO thin films for solar cells via magnetron sputtering

    International Nuclear Information System (INIS)

    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 (?380–1100 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 (? = 380–1100 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 exhite 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.

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

    Science.gov (United States)

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

    2014-07-01

    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 11.6% were achieved. Finally, the project demonstrated the industrial scale feasibility of the developed technologies and materials. Cost of ownership calculations showed that implementation of these technologies on large scale would enable the production of these high efficiency solar modules at manufacturing cost of 0.65 €/Wp with encapsulation costs (0.20 €/Wp) being the dominant costs. Life cycle analysis showed that large scale production of modules based on the technologies developed in Silicon-Light would have an energy payback time of 0.85 years in Central European countries.

  17. Evaluation of back contact in spray deposited SnS thin film solar cells by impedance analysis.

    Science.gov (United States)

    Patel, Malkeshkumar; Ray, Abhijit

    2014-07-01

    The role of back metal (M) contact in sprayed SnS thin film solar cells with a configuration Glass/F:SnO2/In2S3/SnS/M (M = Graphite, Cu, Mo, and Ni) was analyzed and discussed in the present study. Impedance spectroscopy was employed by incorporating constant phase elements (CPE) in the equivalent circuit to investigate the degree of inhomogeneity associated with the heterojunction and M/SnS interfaces. A best fit to Nyquist plot revealed a CPE exponent close to unity for thermally evaporated Cu, making it an ideal back contact. The Bode phase plot also exhibited a higher degree of disorders associated with other M/SnS interfaces. The evaluation scheme is useful for other emerging solar cells developed from low cost processing schemes like spray deposition, spin coating, slurry casting, electrodeposition, etc. PMID:24882468

  18. New layered structures of cuprous chalcogenides as thin film solar cell materials: Cu2Te and Cu2Se.

    Science.gov (United States)

    Nguyen, Manh Cuong; Choi, Jin-Ho; Zhao, Xin; Wang, Cai-Zhuang; Zhang, Zhenyu; Ho, Kai-Ming

    2013-10-18

    The stable crystal structures of two cuprous chalcogenides of Cu2X (X=Te or Se) are predicted using an adaptive genetic algorithm in combination with first-principles density functional theory calculations. Both systems are found to prefer a unique and previously unrecognized layered structure, with the total energies much lower than all structures proposed in the literature so far. The newly discovered structures are further shown to be dynamically and mechanically stable, and possess electronic properties consistent with existing experimental observations. In particular, their layered nature is expected to prevail over other structural forms at the interfaces of thin-film solar cells, and knowledge about the precise atomic structures of the interfaces is a prerequisite for achieving long-term stability and high efficiency of CdTe and Cu(In,Ga)Se2 solar cells. PMID:24182279

  19. Band alignment of SnS/Zn(O,S) heterojunctions in SnS thin film solar cells

    Science.gov (United States)

    Sun, Leizhi; Haight, Richard; Sinsermsuksakul, Prasert; Bok Kim, Sang; Park, Helen H.; Gordon, Roy G.

    2013-10-01

    Band alignment is critical to the performance of heterojunction thin film solar cells. In this letter, we report band alignment studies of SnS/Zn(O,S) heterojunctions with various compositions of Zn(O,S). Valence band offsets (VBOs) are measured by femtosecond laser pump/probe ultraviolet photoelectron spectroscopy (fs-UPS) from which conduction band offsets (CBOs) are calculated by combining with band gaps obtained by optical transmission/reflection measurements. The SnS/Zn(O,S) heterojunctions with S/Zn ratios of 0.37 and 0.50 have desirable small positive CBOs, while a ratio of 0.64 produces an undesirable large positive CBO. The results are consistent with the device performance of SnS/Zn(O,S) solar cells.

  20. Numerical Analysis of Efficiency Enhancement in Plasmonic Thin-Film Solar Cells by Using the SILVACO TCAD Simulator

    International Nuclear Information System (INIS)

    A physical model for simulating plasmonic solar cells (SCs) using the SILVACO TCAD simulator is established and the effects of some factors on the efficiency enhancement of the amorphous silicon thin film SCs are simulated. Through this simulation, it is demonstrated that our method can successfully simulate the optical and electrical properties of plasmonic solar cells without the overestimation of the characteristics and without the neglect of parameter change in the device operation process. It is shown that not only the size and kind of metal nanoparticles but also other factors, such as the surrounding medium, the distance from the bottom of particles to the device surface, and the light incident angle, play important roles in the optical and electrical properties of plasmonic SCs. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  1. Ultra-Lightweight Hybrid Thin-Film Solar Cells: A Survey of Enabling Technologies for Space Power Applications

    Science.gov (United States)

    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.

  2. Photoelectrode thin film of dye-sensitized solar cell fabricated by anodizing method and spin coating and electrochemical impedance properties of DSSC

    International Nuclear Information System (INIS)

    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 ?m, 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 ?m has the lowest charge-conduction resistance (Rk) value 9.276 ? of recombined electron and conduction resistance (Rw) value 3.25 ? of electrons in TiO2.

  3. High surface textured SnO2 hybrid thin films fabricated using the nozzle-spraying process for solar cell applications

    Science.gov (United States)

    Chou, Li-Wei; Lin, Yang-Yi; Wu, Albert T.

    2013-07-01

    High-texture surface tin oxide transparent conductive oxide thin films were directly deposited using the atmospheric pressure chemical vapor deposition technique on nanoparticle-coated glass substrates. A simple nozzle-spraying process was developed for the tin oxide nanoparticle coating process for the high-texture tin oxide thin films. The nozzle-spraying process caused the surface morphology of the tin oxide films to change from a pyramidal shape to a flower-like double texture. The optimum nanoparticle-coated tin oxide thin films have a haze value of 35.0 ± 4.0% and an average visible optical transmittance of 80.6 ± 2.2% in the wavelength range of 400-900 nm. The carrier concentration and mobility of the film were 1.3 ± 0.3 × 1020 cm-3 and 4.0 ± 0.6 cm2 V-1 s-1, respectively. The morphological evolution of the tin oxide thin films was apparent on the hetero-surface of the amorphous glass and multicrystalline tin oxide nanoparticle. This result indicates that the crystalline tin oxide nanoparticle has an important role in the fabrication of the flower-like double texture, and the texture tin oxide thin films are promising transparent conductive oxide materials for thin film solar cells.

  4. Solution Processing of Cadmium Sulfide Buffer Layer and Aluminum-Doped Zinc Oxide Window Layer for Thin Films Solar Cells

    Science.gov (United States)

    Alam, Mahboob; Islam, Mohammad; Achour, Amine; Hayat, Ansar; Ahsan, Bilal; Rasheed, Haroon; Salam, Shahzad; Mujahid, Mohammad

    2014-07-01

    Cadmium sulfide (CdS) and aluminum-doped zinc oxide (Al:ZnO) thin films are used as buffer layer and front window layer, respectively, in thin film solar cells. CdS and Al:ZnO thin films were produced using chemical bath deposition (CBD) and sol-gel technique, respectively. For CBD CdS, the effect of bath composition and temperature, dipping time and annealing temperature on film properties was investigated. The CdS films are found to be polycrystalline with metastable cubic crystal structure, dense, crack-free surface morphology and the crystallite size of either few nanometers or 12-17 nm depending on bath composition. In case of CdS films produced with 1:2 ratio of Cd and S precursors, spectrophotometer studies indicate quantum confinement effect, owing to extremely small crystallite size, with an increase in Eg value from 2.42 eV (for bulk CdS) to 3.76 eV along with a shift in the absorption edge toward 330 nm wavelength. The optimum annealing temperature is 400°C beyond which film properties deteriorate through S evaporation and CdO formation. On the other hand, Al:ZnO films prepared via spin coating of precursor sols containing 0.90-1.10 at.% Al show that, with an increase in Al concentration, the average grain size increases from 28 nm to 131 nm with an associated decrease in root-mean-square roughness. The minimum value of electrical resistivity, measured for the films prepared using 0.95 at.% Al in the precursor sol, is 2.7 × 10-4 ? ? cm. The electrical resistivity value rises upon further increase in Al doping level due to introduction of lattice defects and Al segregation to the grain boundary area, thus limiting electron transport through it.

  5. Determination of optical and mechanical properties of Nb{sub 2}O{sub 5} thin films for solar cells application

    Energy Technology Data Exchange (ETDEWEB)

    Mazur, M. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, Wroc?aw (Poland); Szyma?ska, M., E-mail: magdalena.szymanska@its.waw.pl [Centre for Material Testing and Mechatronics, Motor Transport Institute, Jagiellonska 80, Warsaw (Poland); Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, Warsaw (Poland); Kaczmarek, D. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, Wroc?aw (Poland); Kalisz, M. [Centre for Material Testing and Mechatronics, Motor Transport Institute, Jagiellonska 80, Warsaw (Poland); Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, Warsaw (Poland); Wojcieszak, D.; Domaradzki, J. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, Wroc?aw (Poland); Placido, F. [University of the West of Scotland, High Street, Paisley, PA1 2BE, and SUPA, Scottish Universities Physics Alliance (United Kingdom)

    2014-05-01

    Highlights: • Niobium pentoxide films were prepared by microwave assisted magnetron sputtering. • Optical and mechanical properties of Nb{sub 2}O{sub 5} thin films were investigated. • The surface of thin films was homogenous, crack free and exhibited low RMS roughness. • Prepared Nb{sub 2}O{sub 5} 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 Nb{sub 2}O{sub 5} 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 Nb{sub 2}O{sub 5} 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 Nb{sub 2}O{sub 5} thin films were scratch resistant.

  6. Dependence of charge collection in thin-film CdTe solar cells on the absorber layer parameters

    International Nuclear Information System (INIS)

    Charge collection efficiency in thin-film CdS/CdTe solar cells is discussed taking into consideration losses caused by a finite thickness of the p-CdTe layer, as well as recombination losses at the front and back surfaces. The dependences of the drift and diffusion components of the short-circuit current on the uncompensated acceptor concentration, charge carrier lifetime, recombination velocities at the CdS–CdTe interface and the back surface of the CdTe layer, as well as on its thickness, have been determined and discussed. It is shown that practically the total collection of charges generated by AM1.5 solar radiation, the uncompensated acceptor concentration, electron lifetime and thickness of the CdTe absorber layer should be equal to 1015–1016 cm?3, 10?9–10?8 s and several tens of micrometres, respectively

  7. Polycrystalline-thin-film thermophotovoltaic cells

    Science.gov (United States)

    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.

  8. Thin-film copper indium gallium selenide solar cell based on low-temperature all-printing process.

    Science.gov (United States)

    Singh, Manjeet; Jiu, Jinting; Sugahara, Tohru; Suganuma, Katsuaki

    2014-09-24

    In the solar cell field, development of simple, low-cost, and low-temperature fabrication processes has become an important trend for energy-saving and environmental issues. Copper indium gallium selenide (CIGS) solar cells have attracted much attention due to the high absorption coefficient, tunable band gap energy, and high efficiency. However, vacuum and high-temperature processing in fabrication of solar cells have limited the applications. There is a strong need to develop simple and scalable methods. In this work, a CIGS solar cell based on all printing steps and low-temperature annealing is developed. CIGS absorber thin film is deposited by using dodecylamine-stabilized CIGS nanoparticle ink followed by printing buffer layer. Silver nanowire (AgNW) ink and sol-gel-derived ZnO precursor solution are used to prepare a highly conductive window layer ZnO/[AgNW/ZnO] electrode with a printing method that achieves 16 ?/sq sheet resistance and 94% transparency. A CIGS solar cell based on all printing processes exhibits efficiency of 1.6% with open circuit voltage of 0.48 V, short circuit current density of 9.7 mA/cm(2), and fill factor of 0.34 for 200 nm thick CIGS film, fabricated under ambient conditions and annealed at 250 °C. PMID:25180569

  9. Textured surface boron-doped ZnO transparent conductive oxides on polyethylene terephthalate substrates for Si-based thin film solar cells

    International Nuclear Information System (INIS)

    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 ? 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%).

  10. Study of working pressure on the optoelectrical properties of Al–Y codoped ZnO thin-film deposited using DC magnetron sputtering for solar cell applications

    International Nuclear Information System (INIS)

    Low cost transparent conductive Al–Y codoped ZnO (AZOY) thin-films were prepared on a glass substrate using a DC magnetron sputtering technique with various working pressures in the range of 5–13 mTorr. The relationship among the structural, electrical, and optical properties of sputtered AZOY films was studied as a function of working pressure. The XRD measurements show that the crystallinity of the films degraded as the working gas pressure increased. The AZOY thin-film deposited at a working pressure of 5 mTorr exhibited the lowest electrical resistivity of 4.3 × 10?4 ? cm, carrier mobility of 30 cm2/V s, highest carrier concentration of 4.9 × 1020 cm?3, and high transmittance in the visible region (400–800 nm) of approximately 90%. Compared with Al doped ZnO (AZO) thin-films deposited using DC or RF magnetron sputtering methods, a high carrier mobility was observed in our AZOY thin-films. This result can be used to effectively decrease the absorption of near infrared-rays in solar cell applications. The mechanisms are attributed to the larger transition energy between Ar atoms and sputtering particles and the size compensation of the dopants. Finally, the optimal quality AZOY thin-film was used as an emitter layer (or window layer) to form AZOY/n-Si heterojunction solar cells, which exhibited a stable conversion efficiency (?) of 9.4% under an AM1.5 illumination condition.

  11. Self-assembled hollow nanosphere arrays used as low Q whispering gallery mode resonators on thin film solar cells for light trapping.

    Science.gov (United States)

    Yin, Jun; Zang, Yashu; Yue, Chuang; He, Xu; Li, Jing; Wu, Zhihao; Fang, Yanyan

    2013-10-21

    Optical micro/nano-spherical cavities can be designed to confine light by generating resonances in whispering gallery modes (WGM) and then couple them into the substrate through leaky modes, which can be potentially used in thin film solar cells for absorption enhancements. In this work, the transparent ZnO electrodes in a hollow nanosphere (HNS) structure were proposed as WGM resonators to trap sunlight for the absorption enhancement in silicon thin film solar cells. A low cost and high throughput template based technology was developed to fabricate the ZnO HNS arrays on the Si substrates. Significant simulated absorption enhancement has been demonstrated on the ZnO HNS arrays decorated thin film solar cell with an active layer down to 250 nm in thickness. A 9.3% enhancement in the short circuit current density can be achieved theoretically by comparing the ZnO HNS array modified amorphous Si thin film solar cell with an anti-reflection layer configured cell. PMID:23999602

  12. Spray pyrolysed microporous TiO2 thin films by optimisation of substrate temperature for ‘all sprayed’ solar cells

    Science.gov (United States)

    Santhosh, M. V.; Deepu, D. R.; Geethu, R.; Rajeev Kumar, K.; Sudha Kartha, C.; Vijayakumar, K. P.

    2014-11-01

    Titanium dioxide thin films were deposited on glass substrate at temperatures ranging from 300 °C to 500 °C by a simple, cost effective spray pyrolysis method using commercially available TiO2 powder (Degussa P25). Analyses using scanning electron microscopy (SEM) and atomic force microscopy (AFM) reveal the microporous nature of the films at 350 °C. X-ray diffraction (XRD) and Raman studies reveal that these films are amorphous in nature. The films were subsequently annealed at 500 °C for 2 h, resulting in crystallisation (the tetragonal anatase phase). XPS analysis was effectively used to study the chemical composition of the samples. Finally, optimized microporous TiO2 thin films were used for the fabrication of an ‘all-sprayed’ solar cell utilizing well-established CuInS2 as the absorber layer. The best device under this study has an open-circuit voltage of 409 mV and a short-circuit current density of 3.90 mA cm?2. The efficiency and fill factor were 0.61% and 38%, respectively.

  13. Enhanced electrical properties at boundaries including twin boundaries of polycrystalline CdTe thin-film solar cells.

    Science.gov (United States)

    Li, H; Liu, X X; Lin, Y S; Yang, B; Du, Z M

    2015-04-21

    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

  14. Effect of fluorine plasma treatment with chemically reduced graphene oxide thin films as hole transport layer in organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Effect of fluorine plasma treatment with chemically reduced graphene oxide thin films as hole transport layer in organic solar cells

    International Nuclear Information System (INIS)

    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.

  16. The effect of the transparent conductive oxide on the performance of thin film CdS/CdTe solar cells

    International Nuclear Information System (INIS)

    Thin film CdS/CdTe solar cells fabricated on SnOx -coated glass have been found to give higher efficiencies than similar cells produced on indium-tin oxide (ITO) coated glass substrates. Further investigation implicated the CdS/ITO interface as the cause of the problem; current-voltage measurements revealed that on heating in air the CdS/ITO junction became rectifying. This is consistent with recently reported findings which show that the work function of ITO is raised above that of CdS by oxidative treatments (such as heating in air) which would make the ITO/CdS junction rectifying rather than ohmic. (author)

  17. Improving low pressure chemical vapor deposited zinc oxide contacts for thin film silicon solar cells by using rough glass substrates

    International Nuclear Information System (INIS)

    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.

  18. Improving low pressure chemical vapor deposited zinc oxide contacts for thin film silicon solar cells by using rough glass substrates

    Energy Technology Data Exchange (ETDEWEB)

    Steinhauser, J., E-mail: jerome.steinhauser@oerlikon.com; Boucher, J.-F.; Omnes, E.; Borrello, D.; Vallat-Sauvain, E.; Monteduro, G.; Marmelo, M.; Orhan, J.-B.; Wolf, B.; Bailat, J.; Benagli, S.; Meier, J.; Kroll, U.

    2011-12-01

    Compared to zinc oxide grown (ZnO) on flat glass, rough etched glass substrates decrease the sheet resistance (R{sub sq}) of zinc oxide layers grown on it. We explain this R{sub sq} 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{sup -2} were fabricated.

  19. Structural and Optical Properties Analysis of Sputtered ZnO: Al Thin Films for Cigs Based Solar Cells

    International Nuclear Information System (INIS)

    Al-doped zinc oxide (ZnO: Al) is an outstanding transparent conductive oxide, material with higher bandgap for CIGS based solar cells. Promising results on the optical properties and morphology of deposited ZnO: Al were investigated. Al-dope zinc oxide (ZnO: Al) targets have been deposited on top of ITO coated substrates by RF magnetron sputtering with different thickness. The characterized of films by UV-Vis was show that the transmittances of the films in the visible range are greater than 85 %. From XRD result was indicated that the data of deposited films shows polycrystalline nature with hexagonal wurtzite structure and dominant peak were obtained with preferential orientation (101). Numerous the influences of ZnO:Al investigated which can lead to the fabrication of high efficiency CIGS thin film soar cells. (author)

  20. New diarylmethanofullerene derivatives and their properties for organic thin-film solar cells

    Directory of Open Access Journals (Sweden)

    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.

  1. A Study on the Development of Organic Thin Film Solar Cell Device With Optimized Hole Transfer Layer of PEDOT:PSS

    Directory of Open Access Journals (Sweden)

    Paik-Kyun Shin

    2013-10-01

    Full Text Available Organic thin film solar cells show generally lower power conversion efficiencies than those of the solar cells based on inorganic active materials. To solve the problem diverse research works have been tried: development of new organic semiconductors; modification of internal structure of active layers by means of organic solvent; design and fabrication of vertical device structure; introduction of buffer layer on the side of cathode electrode. Nevertheless, the buffer layer on the side of anode has not been fully optimized. This study is focused on the representative anode-side-buffer layer of Poly(3,4-ethylenedioxythiophene(PEDOT: poly(styrenesulfonate (PSS. PEDOT:PSS is an excellent conducting polymer material with favorably high optical transparency for almost entire range of visible wavelength, which is widely used for organic thin film solar cells as well as for other organic material based electronic devices such as organic light emitting diodes. Aiming for further performance enhancement of organic thin film solar cell device, an optimized condition was studied on the PEDOT:PSS by means of the thickness control and modification of the internal structure via addition of different organic solvents in mixture solution for thin film process.

  2. Highly transparent front electrodes with metal fingers for p-i-n thin-film silicon solar cells

    Science.gov (United States)

    Moulin, Etienne; Müller, 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.

  3. Highly transparent front electrodes with metal fingers for p-i-n thin-film silicon solar cells

    Directory of Open Access Journals (Sweden)

    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.

  4. Development of thin film space solar cells with multi-junction

    International Nuclear Information System (INIS)

    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.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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 transmissio

  6. Evaluation of electrical shunt resistance in laser scribed thin-films for CIGS solar cells on flexible substrates

    Science.gov (United States)

    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.

  7. Conducting glasses recovered from thin film transistor liquid crystal display wastes for dye-sensitized solar cell cathodes.

    Science.gov (United States)

    Chen, C-C; Chang, F-C; Peng, C Y; Wang, H Paul

    2014-11-27

    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 Ni(2+)-?-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

  8. Photoluminescence of epitactical and polycrystalline CuInS2 layers for thin-film solar cells

    International Nuclear Information System (INIS)

    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

  9. Determination of Optimum Film Thickness and Composition of Cu(InAlSe2 Thin Films as anAbsorber for Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Balakrishnan Kavitha

    2011-12-01

    Full Text Available Cu(InAlSe2 [CIAS] thin films have been prepared by chemical bath deposition [CBD] technique. X-ray diffraction [XRD] and Energy dispersive X-ray analysis [EDAX] spectra have been employed to confirm the structure and composition of the prepared films. The structural parameters have been estimated from XRD and EDAX spectra and their variation with film thickness and composition has been discussed in this paper in detail. From the discussion we enabled to find the optimum film thickness and composition of CIAS thin films for solar cell applications.

  10. Tuning of undoped ZnO thin film via plasma enhanced atomic layer deposition and its application for an inverted polymer solar cell

    OpenAIRE

    Mi-jin Jin; Junhyeon Jo; Neupane, Guru P.; Jeongyong Kim; Ki-Seok An; Jung-Woo Yoo

    2013-01-01

    We studied the tuning of structural and optical properties of ZnO thin film and its correlation to the efficiency of inverted solar cell using plasma-enhanced atomic layer deposition (PEALD). The sequential injection of DEZn and O2 plasma was employed for the plasma-enhanced atomic layer deposition of ZnO thin film. As the growth temperature of ZnO film was increased from 100?°C to 300?°C, the crystallinity of ZnO film was improved from amorphous to highly ordered (002) direction ploy-c...

  11. The investigation of ZnO:Al2O3/metal composite back reflectors in amorphous silicon germanium thin film solar cells

    International Nuclear Information System (INIS)

    Different aluminum-doped ZnO (AZO)/metal composite thin films, including AZO/Ag/Al, AZO/Ag/nickel—chromium alloy (NiCr), and AZO/Ag/NiCr/Al, are utilized as the back reflectors of p—i—n 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%

  12. Efficient light incoupling into silicon thin-film solar cells by anti-reflecting MgO/high-compact-AZO with air-side textured glass

    International Nuclear Information System (INIS)

    Light incoupling effects have been enhanced at front interfaces of silicon (Si) thin-film solar cells. Firstly, a MgO thin film was introduced at glass substrate/Al-doped ZnO (AZO) interface for anti-reflection effect. We additionally found that the surface morphology of AZO films grown on MgO film after texture-etching is dependent on the compactness of AZO. For high-compact AZO films, the texture-etched MgO/AZO double layer exhibited significantly enhanced light-scattering capability. Secondly, we made textured surfaces at air/glass interface through simple plasma-etching without sacrificial layers or masks by optimizing the etching pressure. The additional air-side texture contributed to further improvement of total light scattering from the MgO/AZO-coated glass substrate. Fabricated microcrystalline Si thin-film solar cells employing the MgO coated glass with air-side surface texture showed decreased cell reflectance and increased quantum efficiency. The Jsc increased from 21.7 to 26.5 mA cm?2 and final efficiency of 9.49% was achieved. Based on our experimental results, the suggested structure, the MgO coating on glass substrate of which air-side surface is texture-etched, can offer a promising approach to improve the light incoupling and efficiency of Si thin-film solar cells. (paper)

  13. Damp-Heat Induced Degradation of Transparent Conducting Oxides for Thin Film Solar Cells (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Pern, J.; Noufi, R.; Li, X.; DeHart, C.; To, B.

    2008-05-01

    The objectives are: (1) To achieve a high long-term performance reliability for the thin-film CIGS PV modules with more stable materials, device structure designs, and moisture-resistant encapsulation materials and schemes; (2) to evaluate the DH stability of various transparent conducting oxides (TCOs); (3) to identify the degradation mechanisms and quantify degradation rates; (4) to seek chemical and/or physical mitigation methods, and explore new materials. It's important to note that direct exposure to DH represents an extreme condition that a well-encapsulated thin film PV module may never experience.

  14. Performance enhancement of thin film silicon solar cells based on distributed Bragg reflector & diffraction grating

    Directory of Open Access Journals (Sweden)

    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.

  15. Performance enhancement of thin film silicon solar cells based on distributed Bragg reflector & diffraction grating

    Science.gov (United States)

    Dubey, R. S.; Saravanan, S.; Kalainathan, S.

    2014-12-01

    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. Potential of diffraction gratings for implementation as a metal back reflector in thin-film silicon solar cells

    International Nuclear Information System (INIS)

    In thin-film silicon solar cells, novel approaches of light management are important in order to further improve the light confinement in the cells. In this work the potential of the metal periodic diffraction gratings as a back reflector in a microcrystalline silicon-based solar cell is investigated by means of two-dimensional numerical simulations. Two different shapes of the gratings - rectangular and triangular - are included. A de-coupled analysis of two effects, related to the shape and the size of the gratings are investigated: a) the enhancement of the light scattering due to grating and b) the effect of decreased total reflectance (increased optical losses) in the realistic metal silver grating. The results on the partial solar cell structures show significant increase in the scattering, (up to 130 - 180% increased absorptance) especially for the periods around 1- and 2-times the effective light wavelength in the microcrystalline silicon absorber. However, high reductions in the total reflectance (up to 40%) are indicated for the realistic silver gratings, compared to the flat silver back reflector. Triangular diffraction gratings exhibit the potential for optimization over a longer wavelengths range than rectangular gratings

  17. Influence of titania thin film morphology on the photovoltaic action of hybrid titania-P3HT solar cell

    International Nuclear Information System (INIS)

    We report the effects of surface properties of a titania (TiO2) interconnected network structure for photovoltaic applications of organic thin-film solar cell. The electron acceptor layer was obtained by annealing after spin coating of mixture of polyethylene glycol (PEG), Poly(3-hexylthiophene) (P3HT) and Poly(methylmethacrylate) (PMMA) with titania sol-gel solution. The fabrication method was simple and efficient for the increase of titania surface area. The size and height of nanocrystal titania was controlled by spin-coating speed of mixed solution and components of mixed polymer. The bulk-heterojunction solar cells consist of a nanocrystalline titania. In addition, P3HT solar cell showed strong dependence upon surface morphology and the best performance of cell was produced an open circuit voltage of 0.55 V, a short circuit current density of 0.78 mA/cm2, a fill factor of 0.51 and corresponding to a power efficiency of 0.22% (air mass 1.5)

  18. Comparative study on the annealing types on the properties of Cu2ZnSnS4 thin films and their application to solar cells

    Science.gov (United States)

    Hong, Chang Woo; Shin, Seung Wook; Gurav, K. V.; Vanalakar, S. A.; Yeo, Soo Jung; Yang, Han Seung; Yun, Jae Ho; Kim, Jin Hyeok

    2015-04-01

    Comparative studies on the properties of Cu2ZnSnS4 (CZTS) thin films and performance of CZTS thin film solar cells (TFSCs) prepared by different sulfurization types such as commerical furnace (CF) and rapid thermal annealing (RTA) systems have been investigated. The CZTS thin film prepared using CF showed the dense microstructure with many voids and secondary phases, while that prepared using RTA showed the dense microstructure without void and with some secondary phases. The RTA annealed CZTS TFSC have shown better performance than that prepared using CF. The best performance of CZTS TFSC using RTA was 1.9% efficiency (Voc: 505 mV, Jsc: 7.5 mA/cm2 and FF: 50.2%).

  19. Thin films of polyfluorene:fullerene blends - Morphology and its role in solar cell performance

    OpenAIRE

    Björström Svanström, Cecilia

    2007-01-01

    The sun provides us daily with large quantities of energy in the form of light. With the world’s increasing demand of electrical energy the prospect of converting this solar light into electricity is highly tempting. In the strive towards mass-production and low cost solar cells, new types of solar cells are being developed, e.g. solar cells completely based on organic molecules and polymers. These materials offer a promising potential of low cost and large scale manufacturing and have the ad...

  20. Solar control on irradiated Ta2O2 thin films

    International Nuclear Information System (INIS)

    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

  1. Spray Deposited Thin Film Metal Oxide Based Heterojunction for Solar Cell Application

    Directory of Open Access Journals (Sweden)

    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.

  2. Nano-level characterization of silicon thin films and solar cells.

    Czech Academy of Sciences Publication Activity Database

    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: AV?R(CZ) M100101217 Institutional support: RVO:68378271 Keywords : silicon * thin films * atomic force microscopy * photoresponse Subject RIV: BM - Solid Matter Physics ; Magnetism

  3. Advances in Evaporated Solid-Phase-Crystallized Poly-Si Thin-Film Solar Cells on Glass (EVA

    Directory of Open Access Journals (Sweden)

    A. G. Aberle

    2009-01-01

    Full Text Available Polycrystalline silicon thin-film solar cells on glass obtained by solid-phase crystallization (SPC of PECVD-deposited a-Si precursor diodes are capable of producing large-area devices with respectable photovoltaic efficiency. This has not yet been shown for equivalent devices made from evaporated Si precursor diodes (“EVA” solar cells. We demonstrate that there are two main problems for the metallization of EVA solar cells: (i shunting of the p-n junction when the air-side metal contact is deposited; (ii formation of the glass-side contact with low contact resistance and without shunting. We present a working metallization scheme and first current-voltage and quantum efficiency results of 2 cm2 EVA solar cells. The best planar EVA solar cells produced so far achieved fill factors up to 64%, series resistance values in the range of 4-5 Ωcm2, short-circuit current densities of up to 15.6 mA/cm2, and efficiencies of up to 4.25%. Using numerical device simulation, a diffusion length of about 4 μm is demonstrated for such devices. These promising results confirm that the device fabrication scheme presented in this paper is well suited for the metallization of EVA solar cells and that the electronic properties of evaporated SPC poly-Si materials are sufficient for PV applications.

  4. Efficient water-splitting device based on a bismuth vanadate photoanode and thin-film silicon solar cells.

    Science.gov (United States)

    Han, Lihao; Abdi, Fatwa F; van de Krol, Roel; Liu, Rui; Huang, Zhuangqun; Lewerenz, Hans-Joachim; Dam, Bernard; Zeman, Miro; Smets, Arno H M

    2014-10-01

    A hybrid photovoltaic/photoelectrochemical (PV/PEC) water-splitting device with a benchmark solar-to-hydrogen conversion efficiency of 5.2% under simulated air mass (AM) 1.5 illumination is reported. This cell consists of a gradient-doped tungsten-bismuth vanadate (W:BiVO4 ) photoanode and a thin-film silicon solar cell. The improvement with respect to an earlier cell that also used gradient-doped W:BiVO4 has been achieved by simultaneously introducing a textured substrate to enhance light trapping in the BiVO4 photoanode and further optimization of the W gradient doping profile in the photoanode. Various PV cells have been studied in combination with this BiVO4 photoanode, such as an amorphous silicon (a-Si:H) single junction, an a-Si:H/a-Si:H double junction, and an a-Si:H/nanocrystalline silicon (nc-Si:H) micromorph junction. The highest conversion efficiency, which is also the record efficiency for metal oxide based water-splitting devices, is reached for a tandem system consisting of the optimized W:BiVO4 photoanode and the micromorph (a-Si:H/nc-Si:H) cell. This record efficiency is attributed to the increased performance of the BiVO4 photoanode, which is the limiting factor in this hybrid PEC/PV device, as well as better spectral matching between BiVO4 and the nc-Si:H cell. PMID:25138735

  5. Structural, morphological, optical and compositional characterization of spray deposited Ga doped ZnO thin film for Dye-Sensitized Solar Cell application

    Science.gov (United States)

    Amala Rani, A.; Ernest, Suhashini

    2014-11-01

    Zinc Oxide and Gallium doped Zinc Oxide films have been deposited by the Spray Pyrolysis method onto preheated glass substrates using Zinc acetate and Gallium (III) acetyl acetonate as precursors for Zn and Ga ions, respectively. The effect of ZnO and Ga doping on the structural, morphological, optical and chemical properties of sprayed ZnO and Gallium doped ZnO thin films were investigated. XRD studies reveal that the films are crystalline with hexagonal (wurtzite) crystal structure. The average transparency in the visible range was around 75% for the thin film deposited using Gallium doping. X-ray Photoelectron Spectroscopy (XPS) was utilized to view the changes in the oxidation state of ZnO and Gallium doped ZnO thin films. The ZnO and Gallium doped ZnO thin film has been deposited above the Indium Tin Oxide (ITO) coated glass substrate. The efficiency of the obtained DSSC measured for 0.1 M ZnO thin film by sensitizing for 12 h was, ? = 2.5%. Similarly for Gallium doped Zinc Oxide, the efficiency ? is found to be 3.9%, 4.1% and 4.3% for every increase in doping of Gallium concentrations which is utilized for the application of Dye-Sensitized Solar Cell.

  6. Pyrolysis preparation of Cu2ZnSnS4 thin film and its application to counter electrode in quantum dot-sensitized solar cells

    International Nuclear Information System (INIS)

    The Cu2ZnSnS4 (CZTS) thin films with uniform and porous surface feature with the pore size of 100-200 nm were successfully prepared by pyrolysis procedure using the methanol solution containing copper chloride dihydrate (0.06 mol dm?3), zinc chloride (0.03 mol dm?3), stannous chloride dihydrate (0.03 mol dm?3), thiourea (0.48 mol dm?3) and deionized water (1.92 mol dm?3) as precursor solution at 380°C in air atmosphere. Electrochemical impedance spectroscopy was applied to evaluate the electrochemical catalytic activity of the pyrolysis CZTS thin films for redox couple of Sn2-/S2? and the charge transfer resistance was 64.08 ? using the pyrolysis CZTS thin film obtained by repeating the procedure of dipping the FTO substrate into the precursor solution and heating at 380°C for 7 cycles. The assembled quantum dot-sensitized solar cells gave an open-circuit photovoltage of 0.52 V, a short-circuit photocurrent density of 12.96 mA cm?2, and a fill factor of 0.38, corresponding to the photoelectric conversion efficiency of 2.56%. Because the pyrolysis procedure was a facile, low cost and vacuum-free process, and had the advantage of obtaining various porous microstructure thin films and allowing deposition over large areas, the pyrolysis CZTS thin films can serve as an effective counter electrode for QDSCs

  7. Effect of film thickness on the structural, optical and electrical properties of SnO2: F thin films prepared by spray ultrasonic for solar cells applications

    Science.gov (United States)

    Benhaoua, Boubaker; Abbas, Soumaia; Rahal, Achour; Benhaoua, Atmane; Aida, M. S.

    2015-07-01

    In this work, undoped tin dioxide (SnO2) and fluorine doped tin dioxide (SnO2: F) thin films were deposited on 480 °C heated glass using spray ultrasonic technique. SnCl2 and NH4F were used as sources of SnO2 and fluorine doping respectively. Effects of films thickness on the optical, structural and opto-electrical properties of undoped and 6 wt.% fluorine doped SnO2 (FTO) thin films were investigated. Optical transmittance spectra of the films showed high transparency of about 76-84% in visible region. The optical gap, for SnO2 and 6 wt.% F doped SnO2 thin films, were found to be in 3.77-3.93 eV range. X-ray diffraction (XRD) patterns showed that both SnO2 and SnO2: F films were polycrystalline with cassiterite tetragonal crystal structure. The preferential orientation for undoped SnO2 was along (2 1 1) plane whereas F doped SnO2 preferential orientations were along (2 0 0) planes. The calculated grain sizes were in 25.63-33.53 nm average. Figure of merit for FTO thin films revealed maximum value about 9.04 × 10-3 (?-1) at ? = 800 nm. The high conducting and transparent elaborated FTO thin films are promising to be used as window layer in solar cells.

  8. Towards high efficiency thin-film crystalline silicon solar cells: The roles of light trapping and non-radiative recombinations

    International Nuclear Information System (INIS)

    Thin-film solar cells based on silicon have emerged as an alternative to standard thick wafers technology, but they are less efficient, because of incomplete absorption of sunlight, and non-radiative recombinations. In this paper, we focus on the case of crystalline silicon (c-Si) devices, and we present a full analytic electro-optical model for p-n junction solar cells with Lambertian light trapping. This model is validated against numerical solutions of the drift-diffusion equations. We use this model to investigate the interplay between light trapping, and bulk and surface recombination. Special attention is paid to surface recombination processes, which become more important in thinner devices. These effects are further amplified due to the textures required for light trapping, which lead to increased surface area. We show that c-Si solar cells with thickness of a few microns can overcome 20% efficiency and outperform bulk ones when light trapping is implemented. The optimal device thickness in presence of light trapping, bulk and surface recombination, is quantified to be in the range of 10–80??m, depending on the bulk quality. These results hold, provided the effective surface recombination is kept below a critical level of the order of 100?cm/s. We discuss the possibility of meeting this requirement, in the context of state-of-the-art techniques for light trapping and surface passivation. We show that our predictions are within the capability of present day silicon technologies

  9. Atomic-scale distribution of impurities in CuInSe2-based thin-film solar cells

    International Nuclear Information System (INIS)

    Atom Probe Tomography was employed to investigate the distribution of impurities, in particular sodium and oxygen, in a CuInSe2-based thin-film solar cell. It could be shown that sodium, oxygen, and silicon diffuse from the soda lime glass substrate into the CuInSe2 film and accumulate at the grain boundaries. Highly dilute concentrations of sodium and oxygen were measured in the bulk. Selenium was found to be depleted at the grain boundaries. These observations could be confirmed by complementary energy dispersive X-ray spectroscopy studies. Our results support the model proposed by Kronik et al. (1998) , which explains the enhanced photovoltaic efficiency of sodium containing CuInSe2 solar cells by the passivation of selenium vacancies at grain boundaries. -- Research highlights: ? Atom Probe Tomography was employed to investigate the elemental distribution in the CIS absorber layer. ? Na and O atoms were found to be distributed homogeneously in the CuInSe2 grains. ? Correlated enrichments of Na and O atoms were detected, presumably at a grain boundary. ? These enrichments are accompanied by Se depletion in agreement with the 'defect chemical model' proposed by Kronik. ? The 'Na effect' in our CIS-based solar cell can be explained by the passivation of VSe (detrimental donor defects) by O, where Na acts as a catalyst.

  10. In-depth elemental characterization of Cu(In,Ga)Se2 thin film solar cells by means of RBS and PIXE techniques

    Science.gov (United States)

    Karydas, A. G.; Bogdanovic Radovic, I.; Streeck, C.; Kaufmann, C.; Caballero, R.; Rissom, T.; Kanngießer, B.; Beckhoff, B.; Jaksic, M.; Barradas, N. P.

    2014-07-01

    Thin films based on Cu(In,Ga)Se2 are used as absorber cells in photovoltaic devices. In and Ga graded depth profiles are designed to optimize the solar cell performance. Simultaneous Rutherford Backscattering Spectrometry (RBS) and Particle Induced X-ray Emission (PIXE) with 3 MeV 4He ions were used in conjunction to determine the depth profile of all the heavy elements in Cu(In,Ga)Se2 absorbers and complete solar cells. The RBS and PIXE data from one sample were analyzed synergistically, providing reliable depth profiles that satisfy all the data collected. An uncertainty analysis was done, probing the sensitivity of the analysis to different assumptions. The analytical possibilities of the combined RBS/PIXE alpha beam measurements of the CIGSe thin film solar cells, as well as the uncertainties induced in the quantitative methodology are discussed and critically assessed.

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

    Science.gov (United States)

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

    2005-01-01

    Dual junction amorphous silicon (a-Si) solar cells produced on polyimide substrate have been selected as the best candidate to produce a lightweight solar array for the PowerSphere program. The PowerSphere concept features a space-inflatable, geodetic solar array approximately 0.6 meters in diameter and capable of generating about 20W of electrical power. Trade studies of various wiring concepts and connection methods led to an interconnect design with a copper contact that wraps around the edge, to the back of the solar cell. Applying Plasma Vapor Deposited (PVD) copper film to both sides and the edge of the solar cell produces the wrap around contact. This procedure results in a contact pad on the back of the solar cell, which is then laser welded to a flex circuit material. The flex circuit is constructed of copper in a custom designed routing pattern, and then sandwiched in a Kapton insulation layer. The flex circuit then serves as the primary power distribution system between the solar cells and the spacecraft. Flex circuit material is the best candidate for the wiring harness because it allows for low force deployment of the solar cells by the inflatable hinges on the PowerSphere. An additional frame structure, fabricated and assembled by ILC Dover, will reinforce the wrap around contact-flex blanket connection, thus providing a mechanically robust solar cell interconnect for the PowerSphere multifunctional program. The PowerSphere team will use the wraparound contact design approach as the primary solution for solar cell integration and the flex blanket for power distribution.

  12. Cocktails of paste coatings for performance enhancement of CuInGaS(2) thin-film solar cells.

    Science.gov (United States)

    An, Hee Sang; Cho, Yunae; Park, Se Jin; Jeon, Hyo Sang; Hwang, Yun Jeong; Kim, Dong-Wook; Min, Byoung Koun

    2014-01-22

    To fabricate low-cost and printable wide-bandgap CuInxGa1-xS2 (CIGS) thin-film solar cells, a method based on a precursor solution was developed. In particular, under this method, multiple coatings with two pastes with different properties (e.g., viscosity) because of the different binder materials added were applied. Paste A could form a thin, dense layer enabling a high-efficiency solar cell but required several coating and drying cycles for the desired film thickness. On the other hand, paste B could easily form one-micrometer-thick films by means of a one-time spin-coating process but the porous microstructure limited the solar cell performance. Three different configurations of the CIGS films (A + B, B + A, and A + B + A) were realized by multiple coatings with the two pastes to find the optimal stacking configuration for a combination of the advantages of each paste. Solar cell devices using these films showed a notable difference in their photovoltaic characteristics. The bottom dense layer increased the minority carrier diffusion length and enhanced the short-circuit current. The top dense layer could suppress interface recombination but exhibited a low optical absorption, thereby decreasing the photocurrent. As a result, the A + B configuration could be suggested as a desirable simple stacking structure. The solar cell with A + B coating showed a highly improved efficiency (4.66%) compared to the cell with a film prepared by paste B only (2.90%), achieved by simple insertion of a single thin (200 nm), dense layer between the Mo back contact and a thick porous CIGS layer. PMID:24377257

  13. Single and multijunction silicon based thin film solar cells on a flexible substrate with absorber layers made by hot-wire CVD

    OpenAIRE

    Li, Hongbo

    2007-01-01

    With the worldwide growing concern about reliable energy supply and the environmental problems of fossil and nuclear energy production, the need for clean and sustainable energy sources is evident. Solar energy conversion, such as in photovoltaic systems, can play a major role in the urgently needed energy transition in electricity production. Solar cells based on thin film silicon and its alloys are a promising candidate that is capable of fulfilling the fast increasing demand of a reliable ...

  14. Light trapping in thin film solar cells using textured photonic crystal

    Science.gov (United States)

    Yi, Yasha (Somerville, MA); Kimerling, Lionel C. (Concord, MA); Duan, Xiaoman (Amesbury, MA); Zeng, Lirong (Cambridge, MA)

    2009-01-27

    A solar cell includes a photoactive region that receives light. A photonic crystal is coupled to the photoactive region, wherein the photonic crystal comprises a distributed Bragg reflector (DBR) for trapping the light.

  15. Light trapping in thin film silicon solar cells by Raman spectroscopy.

    Czech Academy of Sciences Publication Activity Database

    Ganzerová, Kristína; Ledinský, Martin; Fejfar, Antonín; Ko?ka, Jan

    Tokyo : ACEEES, Tokyo Institute of Technology, 2013. s. 1-2. [International Education Forum on Enviroment and Energy Science /2./. 13.12.2013-17.12.2013, Los Angeles] R&D Projects: GA MPO FR-TI2/736; GA MŠk(CZ) LM2011026 Grant ostatní: AV?R(CZ) M100101216; AV ?R(CZ) M100101217 Institutional support: RVO:68378271 Keywords : Raman spectroscopy * thin film Subject RIV: BM - Solid Matter Physics ; Magnetism

  16. Optical management in high-efficiency thin-film silicon micromorph solar cells with a silicon oxide based intermediate reflector

    Energy Technology Data Exchange (ETDEWEB)

    Domine, Didier; Buehlmann, Peter; Bailat, Julien; Billet, Adrian; Feltrin, Andrea; Ballif, Christophe [Institute of Microtechnology (IMT), University of Neuchatel (Switzerland)

    2008-08-15

    In the effort to increase the stable efficiency of thin film silicon micromorph solar cells, a silicon oxide based intermediate reflector (SOIR) layer is deposited in situ between the component cells of the tandem device. The effectiveness of the SOIR layer in increasing the photo-carrier generation in the a-Si:H top absorber is compared for p-i-n devices deposited on different rough, highly transparent, front ZnO layers. High haze and low doping level for the front ZnO strongly enhance the current density (J{sub sc}) in the {mu}c-Si:H bottom cell whereas J{sub sc} in the top cell is influenced by the angular distribution of the transmitted light and by the reflectivity of the SOIR related to different surface roughness. A total J{sub sc} of 26.8 mA/cm{sup 2} and an initial conversion efficiency of 12.6% are achieved for 1.2 cm{sup 2} cells with top and bottom cell thicknesses of 300 nm and 3 {mu}m, and without any anti-reflective coating on the glass. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Semiconductor heterostructures and optimization of light-trapping structures for efficient thin-film solar cells

    International Nuclear Information System (INIS)

    Sub-wavelength photonic structures and nanoscale materials have the potential to greatly improve the efficiencies of solar cells by enabling maximum absorption of sunlight. Semiconductor heterostructures provide versatile opportunities for improving absorption of infrared radiation in photovoltaic devices, which accounts for half of the power in the solar spectrum. These ideas can be combined in quantum-well solar cells and related structures in which sub-wavelength metal and dielectric scattering elements are integrated for light trapping. Measurements and simulations of GaAs solar cells with less than one micron of active material demonstrate the benefits of incorporating In(Ga)As quantum-wells and quantum-dots to improve their performance. Simulations that incorporate a realistic model of absorption in quantum-wells show that the use of broadband photonic structures with such devices can substantially improve the benefit of incorporating heterostructures, enabling meaningful improvements in their performance

  18. Towards high-efficiency thin-film silicon solar cells with the “micromorph” concept

    OpenAIRE

    Meier, Johannes; Dubail, S.; Platz, R.; Torres, Pedro; Kroll, U.; Anna Selvan, J. A.; Pellaton Vaucher, N.; Hof, Ch; Fischer, D.; Keppner, Herbert; Flu?ckiger, R.; Shah, Arvind; Shklover, V.; Ufert, K. -d

    2008-01-01

    Tandem solar cells with a microcrystalline silicon bottom cell (1 eV gap) and an amorphous-silicon top cell (1.7 eV gap) have recently been introduced by the authors; they were designated as “micromorph” tandem cells. As of now, stabilised efficiencies of 11.2% have been achieved for micromorph tandem cells, whereas a 10.7% cell is confirmed by ISE Freiburg. Micromorph cells show a rather low relative temperature coefficient of 0.27%/K. Applying the grain-boundary trapping model so far de...

  19. Physical vapor deposition and analysis of copper indium aluminum diselenide thin films for high band gap solar cells

    Science.gov (United States)

    Haimbodi, Moses Warotua

    CuInSe2 films and related alloys have been used to fabricate the highest efficiency thin film solar cells. Alloying CuInSe2 with CuAlSe2 provides a way to engineer the band gap of the resulting films from 1 to 2.7 eV, thereby providing a pathway for improving device performance. In this work, thin films of CuIn1-xAlxSe 2 obtained by multi-source PVD were characterized and investigated for their potential use as high band gap solar cells. The band gap of the films was varied by controlling the [Al]/[Al + In] ratio. Deposition of these films with varying [Cu]/[Al + In] ratios and thickness (1--4 mum) was carried out at substrate temperatures from 350--530°C. CuIn1-xAlxSe2 based solar cells have been fabricated using the structure glass/Mo/CuIn1-xAl xSe2/CdS/ZnO/grid. The effect of varying the band gap on device performance will be discussed. The highest efficiency obtained in this work is 11% using a film with Eg ? 1.3 eV. For high Al content, x > 0.3, device-performance decreases mainly due to poor FF similar to that observed in CuIn1-xGaxSe2 devices and is attributed to poor minority carrier collection. For CuIn1-xAlxSe2 films with x = 1, data is analyzed and presented with respect to [Cu]/[Al] and Se to total metal flux ratio, RSe/RM. Phase analysis shows that the resulting films contain different phases that depend on these parameters. Several of these films also contain concentrations of oxygen varying from 12 to 60 at. % as the [Cu]/[Al] ratio decreases. For RSe/R M > 10, a new structure we label as CuxAlySe z was observed. The oxygen content in all of the films obtained under RSe/RM > 10 vary between 1--3 at. %. Based on the Cu-Se, Al-Se, Cu-Al binary and the Cu2Se-Al2Se 3 pseudo-binary phase diagrams, a phenomenological film growth model is presented showing that the film growth kinetics are controlled by the delivery of Se.

  20. Mixed-phase p-type silicon oxide containing silicon nanocrystals and its role in thin-film silicon solar cells

    Science.gov (United States)

    Cuony, P.; Marending, M.; Alexander, D. T. L.; Boccard, M.; Bugnon, G.; Despeisse, M.; Ballif, C.

    2010-11-01

    Lower absorption, lower refractive index, and tunable resistance are three advantages of amorphous silicon oxide containing nanocrystalline silicon grains (nc-SiOx) compared to microcrystalline silicon (?c-Si), when used as a p-type layer in ?c-Si thin-film solar cells. We show that p-nc-SiOx with its particular nanostructure increases ?c-Si cell efficiency by reducing reflection and parasitic absorption losses depending on the roughness of the front electrode. Furthermore, we demonstrate that the p-nc-SiOx reduces the detrimental effects of the roughness on the electrical characteristics, and significantly increases ?c-Si and Micromorph cell efficiency on substrates until now considered too rough for thin-film silicon solar cells.

  1. Hybrid organic/inorganic thin-film multijunction solar cells exceeding 11% power conversion efficiency.

    Science.gov (United States)

    Roland, Steffen; Neubert, Sebastian; Albrecht, Steve; Stannowski, Bernd; Seger, Mark; Facchetti, Antonio; Schlatmann, Rutger; Rech, Bernd; Neher, Dieter

    2015-02-18

    Hybrid multijunction solar cells comprising hydrogenated amorphous silicon and an organic bulk heterojunction are presented, reaching 11.7% power conversion efficiency. The benefits of merging inorganic and organic subcells are pointed out, the optimization of the cells, including optical modeling predictions and tuning of the recombination contact are described, and an outlook of this technique is given. PMID:25581318

  2. Depth Profile Analysis of Amorphous Silicon Thin Film Solar Cells by Pulsed Radiofrequency Glow Discharge Time of Flight Mass Spectrometry

    Science.gov (United States)

    Alvarez-Toral, Aitor; Sanchez, Pascal; Menéndez, Armando; Pereiro, Rosario; Sanz-Medel, Alfredo; Fernández, Beatriz

    2015-02-01

    Among the different solar cell technologies, amorphous silicon (a-Si:H) thin film solar cells (TFSCs) are today very promising and, so, TFSCs analytical characterization for quality control issues is increasingly demanding. In this line, depth profile analysis of a-Si:H TFSCs on steel substrate has been investigated by using pulsed radiofrequency glow discharge-time of flight mass spectrometry (rf-PGD-TOFMS). First, to discriminate potential polyatomic interferences for several analytes (e.g., 28Si+, 31P+, and 16O+) appropriate time positions along the GD pulse profile were selected. A multi-matrix calibration approach, using homogeneous certified reference materials without hydrogen as well as coated laboratory-made standards containing hydrogen, was employed for the methodological calibration. Different calibration strategies (in terms of time interval selection on the pulse profile within the afterglow region) have been compared, searching for optimal calibration graphs correlation. Results showed that reliable and fast quantitative depth profile analysis of a-Si:H TFSCs by rf-PGD-TOFMS can be achieved.

  3. Study of the junction and carrier lifetime properties of a spray-deposited CZTS thin-film solar cell

    International Nuclear Information System (INIS)

    The Cu2ZnSnS4 (CZTS) thin-film solar cell fabricated entirely by a spray pyrolysis process was investigated under diffused white light in the present study. A CdS layer was developed as a heterojunction partner. The structural, morphological and photovoltaic characterization of an as-prepared stoichiometric CZTS film was carried out. The diode ideality factor n was found to be in the range of 1.2–5.6 in the forward bias region and it is explained by the Frenkel–Poole conduction model. The solar cell exhibited open-circuit voltage (Voc) of 157.25 mV, short-circuit current density (Jsc) of 3.024 mA cm?2 and fill factor (FF) of 24.77% at an incident irradiance of 200 W m?2 from the white LED source. The effective minority carrier lifetime of 263 ?s was confirmed by the open-circuit voltage decay fitting under pulsed monochromatic LED excitation. (paper)

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

    Directory of Open Access Journals (Sweden)

    Soppe W.

    2014-07-01

    Full Text Available 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 11.6% were achieved. Finally, the project demonstrated the industrial scale feasibility of the developed technologies and materials. Cost of ownership calculations showed that implementation of these technologies on large scale would enable the production of these high efficiency solar modules at manufacturing cost of 0.65 €/Wp with encapsulation costs (0.20 €/Wp being the dominant costs. Life cycle analysis showed that large scale production of modules based on the technologies developed in Silicon-Light would have an energy payback time of 0.85 years in Central European countries.

  5. Electron energy-loss spectroscopy of boron-doped layers in amorphous thin film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Duchamp, M.; Boothroyd, C.B.; Dunin-Borkowski, R.E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Gruenberg Institute (PGI), Forschungszentrum Juelich, D-52425 Juelich (Germany); Moreno, M.S. [Centro Atomico Bariloche, 8400 - S. C. de Bariloche (Argentina); Van Aken, B.B.; Soppe, W.J. [ECN Solar Energy, High Tech Campus, Building 5, 5656 AE Eindhoven (Netherlands)

    2013-03-07

    Electron energy-loss spectroscopy (EELS) is used to study p-doped layers in n-i-p amorphous thin film Si solar cells grown on steel foil substrates. For a solar cell in which an intrinsic amorphous hydrogenated Si (a-Si-H) layer is sandwiched between 10-nm-thick n-doped and p-doped a-Si:H layers, we assess whether core-loss EELS can be used to quantify the B concentration. We compare the shape of the measured B K edge with real space ab initio multiple scattering calculations and show that it is possible to separate the weak B K edge peak from the much stronger Si L edge fine structure by using log-normal fitting functions. The measured B concentration is compared with values obtained from secondary ion mass spectrometry, as well as with EELS results obtained from test samples that contain ?200-nm-thick a-Si:H layers co-doped with B and C. We also assess whether changes in volume plasmon energy can be related to the B concentration and/or to the density of the material and whether variations of the volume plasmon line-width can be correlated with differences in the scattering of valence electrons in differently doped a-Si:H layers.

  6. Analysis of impact of non-uniformities on thin-film solar cells and modules with two-dimesional simulations

    Science.gov (United States)

    Koishiyev, Galymzhan T.

    Clean and environmentally friendly photovoltaic (PV) technologies are now generally recognized as an alternative solution to many global-scale problems such as energy demand, pollution, and environment safety. The cost ($/kWh) is the primary challenge for all PV technologies. In that respect, thin-film polycrystalline PV technology (CdTe, Cu(In,Ga)Se2, etc), due to its fast production line, large area panels and low material usage, is one of the most promising low-cost technologies. Due to their granular structure, thin-film solar cells are inherently non-uniform. Also, inevitable fluctuations during the multistep deposition process of large area thin-film solar panels and specific manufacturing procedures such as scribing result in non-uniformities. Furthermore, non-uniformities can occur, become more severe, or increase in size during the solar-panel's life cycle due to various environmental conditions (i.e. temperature variation, shading, hail impact, etc). Non-uniformities generally reduce the overall efficiency of solar cells and modules, and their effects therefore need to be well understood. This thesis focuses on the analysis of the effect of non-uniformities on small size solar cells and modules with the help of numerical simulations. Even though the 2-D model developed here can analyze the effect of non-uniformities of any nature, only two specific types of microscopic non-uniformities were addressed here: shunts and weak-diodes. One type of macroscopic non-uniformity, partial shading, was also addressed. The circuit model developed here is a network of diodes, current-sources, and transparent-conductive-oxide (TCO) resistors. An analytic relation between the TCO-resistor, which is the primary model parameter, and TCO sheet resistance rhoS, which is the corresponding physical parameter, was derived. Based on the model several useful general results regarding a uniform cell were deduced. In particular, a global parameter delta, which determines the performance of a uniform solar cell depending on sheet resistance rhoS, cell length L, and other basic parameters, was found. The expression for the lumped series resistance in terms of physical parameters was also derived. Primary power loss mechanisms in the uniform case and their dependence on rhoS, L, and light generated current JL were determined. Similarly, power losses in a small-area solar cell with either a shunt or a weak-microdiode were identified and their dependence on rho S, JL, and location of the non-uniformity with respect to the current collecting contact was studied. The impact of multiple identical non-uniformities (shunts or weak-diodes) on the performance of a module was analyzed and estimates of efficiency loss were presented. It was found that the efficiency of the module strongly depends not only on the severity and fractional area of non-uniformities but also on their distribution pattern. A numerical parameter characterizing distribution pattern of non-uniformities was introduced. The most and least favorable distribution patterns of shunts and weak-diodes over the module area were determined. Experimentally, non-uniformities may be detected with the help of spatially resolved measurements such as electroluminescence (EL). The 2-D circuit model was also used to develop the general framework to extract useful information from experimental EL data. In particular, a protocol that can help distinguish a shunt from a weak-diode and estimate the severity of the non-uniformity based on the EL data was developed. Parts of these simulation results were verified with experimental EL data obtained by other authors. The thesis also discusses the effect of partial shading (a macroscopic nonuniformity) on the operation and safety of thin-film solar panels. A detailed analysis of the current-voltage characteristics of partially shaded module was performed. Conditions that result in a shaded cell experiencing high reverse voltage were shown. A mathematical formalism was developed to distinguish two extremes: when reverse-bias shunting or breakdown dominates

  7. Grazing incidence X-ray fluorescence analysis of buried interfaces in periodically structured crystalline silicon thin-film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Eisenhauer, David; Preidel, Veit; Becker, Christiane [Young Investigator Group Nanostructured Silicon for Photovoltaic and Photonic Implementations (Nano-SIPPE), Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany); Pollakowski, Beatrix; Beckhoff, Burkhard [Physikalisch-Technische Bundesanstalt, Berlin (Germany); Baumann, Jonas; Kanngiesser, Birgit [Institut fuer Optik und Atomare Physik, Technische Universitaet Berlin (Germany); Amkreutz, Daniel; Rech, Bernd [Institut Silizium Photovoltaik, Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany); Back, Franziska; Rudigier-Voigt, Eveline [SCHOTT AG, Mainz (Germany)

    2015-03-01

    We present grazing incidence X-ray fluorescence (GIXRF) experiments on 3D periodically textured interfaces of liquid phase crystallized silicon thin-film solar cells on glass. The influence of functional layers (SiO{sub x} or SiO{sub x}/SiC{sub x}) - placed between glass substrate and silicon during crystallization - on the final carbon and oxygen contaminations inside the silicon was analyzed. Baring of the buried structured silicon surface prior to GIXRF measurement was achieved by removal of the original nano-imprinted glass substrate by wet-chemical etching. A broad angle of incidence distribution was determined for the X-ray radiation impinging on this textured surface. Optical simulations were performed in order to estimate the incident radiation intensity on the structured surface profile considering total reflection and attenuation effects. The results indicate a much lower contamination level for SiO{sub x} compared to the SiO{sub x}/SiC{sub x} interlayers, and about 25% increased contamination when comparing structured with planar silicon layers, both correlating with the corresponding solar cell performances. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Grazing incidence X-ray fluorescence analysis of buried interfaces in periodically structured crystalline silicon thin-film solar cells

    International Nuclear Information System (INIS)

    We present grazing incidence X-ray fluorescence (GIXRF) experiments on 3D periodically textured interfaces of liquid phase crystallized silicon thin-film solar cells on glass. The influence of functional layers (SiOx or SiOx/SiCx) - placed between glass substrate and silicon during crystallization - on the final carbon and oxygen contaminations inside the silicon was analyzed. Baring of the buried structured silicon surface prior to GIXRF measurement was achieved by removal of the original nano-imprinted glass substrate by wet-chemical etching. A broad angle of incidence distribution was determined for the X-ray radiation impinging on this textured surface. Optical simulations were performed in order to estimate the incident radiation intensity on the structured surface profile considering total reflection and attenuation effects. The results indicate a much lower contamination level for SiOx compared to the SiOx/SiCx interlayers, and about 25% increased contamination when comparing structured with planar silicon layers, both correlating with the corresponding solar cell performances. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. High efficiency thin-film GaAs solar cells. First interim report, March 1--August 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Stirn, R.J.

    1977-12-01

    The objective is to demonstrate the feasibility of producing high-efficiency (15% or greater) thin-film GaAs solar cells with costs suitable for terrestrial solar electric power generation. The approach is that of growing GaAs by organio-metallic chemical vapor deposition on recrystallized germanium (Ge) films previously deposited on metal substrates and fabricating AMOS (Antireflecting Metal-Oxide-Semiconductor) solar cells on the GaAs. Previously it had been determined that a water vapor-grown native oxide (temperature = 25/sup 0/C) was the most useful native oxide for AMOS cells. A new chemical surface preparation prior to oxide growth led to more uniform oxides and reduced interface contamination, yielding lower reverse saturation current densities, a near-unity diode ideality factor, and better reproducibility. Substituting silver (Ag) for gold metallization showed no change in starting cell efficiency, but did greatly improve high temperature stability of the AMOS solar cell. A new study was completed on antireflection coatings on AMOS GaAs solar cells, taking into account the spectral response of the cell and nature of the solar spectra, and the results submitted for publication. XPS (X-ray Photoelectron Spectroscopy) studies had found earlier that the more efficient native oxides had primarily As/sub 2/O/sub 3/ and Ga/sub 2/O/sub 3/ with little GaAsO/sub 4/. A new chemical step etching was developed which can be used to profile the oxide in 5- to 7-A/sup 0/ steps without modifying the oxide chemistry as does ion sputtering. A new Schottky barrier structure is described which can give cell efficiencies up to 16% without oxide interfacial layer effects and 20 to 22% with a moderate interfacial layer effect. AMOS solar cells fabricated on sliced polycrystalline GaAs wafers with 100- to 500-..mu..m grains using Sb/sub 2/O/sub 3/ deposited oxides showed 14% cell efficiency compared to 16.2% in a region with few grains.

  10. Development of rear surface passivated Cu(In,Ga)Se-2 thin film solar cells with nano-sized local rear point contacts

    OpenAIRE

    Vermang, Bart; Fja?llstro?m, Viktor; Pettersson, Jonas; Salome?, Pedro; Edoff, Marika

    2013-01-01

    For the first time, a novel rear contacting structure for copper indium gallium (di)selenide (CIGS) thin film solar cells is discussed theoretically, developed in an industrially viable way, and demonstrated in tangible devices. The proposed cell design reduces back contacting area by combining a rear surface passivation layer and nano-sized local point contacts. Atomic layer deposition (ALD) of Al2O3 is used to passivate the CIGS surface and the formation of nano-sphere shaped precipitates i...

  11. Potential of thin-film silicon solar cells by using high haze TCO superstrates

    International Nuclear Information System (INIS)

    Potential improvements in the performance of tandem amorphous silicon/microcrystalline silicon (a-Si:H/?c-Si:H) solar cells, related to the TCO superstrates with enhanced scattering properties are studied. In particular, optical effects of a high haze double textured (W-textured) SnO2:F TCO superstrate are analyzed and compared to the properties of the pyramidal type SnO2:F TCO superstrate. Solar cell with W-textured superstrate exhibits higher long-wavelength external quantum efficiency of the bottom ?c-Si:H cell than the one with pyramidal type TCO superstrate. Optical simulations are employed to study the potential improvements of the solar cell performance if ideal haze parameter (H = 1) and/or a broad angular distribution function (Lambertian) of scattered light are applied to textured interfaces in the solar cell structure. Simulations reveal significant improvements in long-wavelength quantum efficiencies if a broad angular distribution function of scattered light is applied. Optical losses in the cells with enhanced scattering properties are analysed and evaluated in terms of short-circuit current losses in the supporting layers and losses due to reflected light.

  12. Efficient hole-blocking layer-free planar halide perovskite thin-film solar cells.

    Science.gov (United States)

    Ke, Weijun; Fang, Guojia; Wan, Jiawei; Tao, Hong; Liu, Qin; Xiong, Liangbin; Qin, Pingli; Wang, Jing; Lei, Hongwei; Yang, Guang; Qin, Minchao; Zhao, Xingzhong; Yan, Yanfa

    2015-01-01

    Efficient lead halide perovskite solar cells use hole-blocking layers to help collection of photogenerated electrons and to achieve high open-circuit voltages. Here, we report the realization of efficient perovskite solar cells grown directly on fluorine-doped tin oxide-coated substrates without using any hole-blocking layers. With ultraviolet-ozone treatment of the substrates, a planar Au/hole-transporting material/CH3NH3PbI3-xClx/substrate cell processed by a solution method has achieved a power conversion efficiency of over 14% and an open-circuit voltage of 1.06?V measured under reverse voltage scan. The open-circuit voltage is as high as that of our best reference cell with a TiO2 hole-blocking layer. Besides ultraviolet-ozone treatment, we find that involving Cl in the synthesis is another key for realizing high open-circuit voltage perovskite solar cells without hole-blocking layers. Our results suggest that TiO2 may not be the ultimate interfacial material for achieving high-performance perovskite solar cells. PMID:25798925

  13. Chemical interaction at the buried silicon/zinc oxide thin-film solar cell interface as revealed by hard X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Highlights: •We used HAXPES to identify chemical interactions at the buried silicon/aluminum-doped zinc oxide thin-film solar cell interface. •The results indicate a diffusion of zinc and aluminum into the silicon upon annealing procedures which are part of the solar cell processing. •The contamination of the silicon may be detrimental for the solar cell performance. -- Abstract: Hard X-ray photoelectron spectroscopy (HAXPES) is used to identify chemical interactions (such as elemental redistribution) at the buried silicon/aluminum-doped zinc oxide thin-film solar cell interface. Expanding our study of the interfacial oxidation of silicon upon its solid-phase crystallization (SPC), in which we found zinc oxide to be the source of oxygen, in this investigation we address chemical interaction processes involving zinc and aluminum. In particular, we observe an increase of zinc- and aluminum-related HAXPES signals after SPC of the deposited amorphous silicon thin films. Quantitative analysis suggests an elemental redistribution in the proximity of the silicon/aluminum-doped zinc oxide interface – more pronounced for aluminum than for zinc – as explanation. Based on these insights the complex chemical interface structure is discussed

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

    OpenAIRE

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

    2014-01-01

    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 1...

  15. Characterization of defects induced by Ar beam irradiation in thin films used for solar cell devices

    International Nuclear Information System (INIS)

    The novel technique of Ion Mixing (IM), using 300 keV 40Ar+ ion irradiation, was used to induce defects in thin films Ge vacuum deposited onto Si wafer substrates. The defects are characterized by Thermoluminescence (TL) and structural changes are investigated by Rutherford backscattering (RBS). Evidence of new defect states are observed with Ar doses reaching 3x1016 ions/cm2. Kinetic analysis of a series of observed glow (GL-) curves are deconvoluted to determine the trapping parameters (activation energy, E, kinetic order, b, and concentration of electrons, no) associated with charge transfer processes

  16. Mapping electronic properties of the thin films for solar cells with nanometer resolution.

    Czech Academy of Sciences Publication Activity Database

    Fejfar, Antonín; Rezek, Bohuslav; Mates, Tomáš; Honda, Shinya; ?ermák, Jan; Ledinský, Martin; Vetushka, Aliaksi; Stuchlík, Ji?í; Stuchlíková, The-Ha; Šípek, Emil; Ko?ka, Jan

    Tokyo : Japan Society for the Promotion of Science, 2008, s. 62-66. [Workshop on the Future Direction of Photovoltaics /4./. Aogaku Kaikan, Tokyo (JP), 06.03.2008-07.03.2008] R&D Projects: GA MŠk(CZ) LC06040; GA AV ?R KAN400100701; GA MŠk LC510; GA MŽP(CZ) SN/3/172/05 Institutional research plan: CEZ:AV0Z10100521 Keywords : silicon * thin films * photovoltaics Subject RIV: BM - Solid Matter Physics ; Magnetism

  17. Chemically deposited lead sulfide and bismuth sulfide thin films and Bi2S3/PbS solar cells

    International Nuclear Information System (INIS)

    Solar cells with a short-circuit current density (Jsc) of 6 mA/cm2, an open circuit voltage (Voc) of 280 mV and a conversion efficiency of 0.5% under a 1000 W/m2 solar radiation were prepared by sequential chemical deposition of Bi2S2 (160 nm) and PbS (400 nm) thin films. The optical band gap (Eg) of Bi2S3 (160 nm) decreased from 1.67 to 1.61 eV upon heating the as-deposited film at 250 oC in air for 15 min to make it crystalline, but also reduced its thickness to 100 nm. Photoconductivity of this film is 0.003 (? cm)-1. The Eg of PbS film (200 nm) deposited at 25 oC (24 h) is 0.57 eV, and is 0.49 eV for the film deposited at 40 oC. The electrical conductivity of the latter is 0.48 (? cm)-1. The photo-generated current density for a Bi2S3(100 nm)/PbS(300 nm) absorber stack is above 40 mA/cm2 under AM 1.5 G (1000 W/m2) solar radiation. However, the optical losses in the cell structure reduces the Jsc. Spectral sensitivity of the external quantum efficiency of the cell establishes the contribution of Bi2S3 and PbS to Jsc. The energy level diagram of the cell structure suggests a built-in potential of 470 mV for the present case. Six series-connected cells gave the Voc of 1.4 V and Jsc of 5 mA/cmsc of 5 mA/cm2.

  18. Development of a Wide Bandgap Cell for Thin Film Tandem Solar Cells: Final Technical Report, 6 November 2003 - 5 January 2007

    Energy Technology Data Exchange (ETDEWEB)

    Shafarman, W.; McCandless, B.

    2008-08-01

    The objective of this research program was to develop approaches for a transparent wide-bandgap cell to be used in a thin-film tandem polycrystalline solar cell that can ultimately attain 25% efficiency. Specific goals included the research and development of Cu(InGa)(SeS)2 and Cd1-xZnxTe alloys with a bandgap from 1.5 to 1.8 eV, demonstrating the potential of a 15% cell efficiency with a transparent contact, and supporting the High Performance PV Program. This Final Report presents results that emphasize the 3rd phase of the program.

  19. Micromorph thin-film silicon solar cells with transparent high-mobility hydrogenated indium oxide front electrodes

    Science.gov (United States)

    Battaglia, Corsin; Erni, Lukas; Boccard, Mathieu; Barraud, Loris; Escarré, Jordi; Söderström, Karin; Bugnon, Grégory; Billet, Adrian; Ding, Laura; Despeisse, Matthieu; Haug, Franz-Josef; Wolf, Stefaan De; Ballif, Christophe

    2011-06-01

    We investigate the performance of hydrogenated indium oxide as a transparent front electrode for micromorph thin-film silicon solar cells on glass. Light trapping is achieved by replicating the morphology of state-of-the-art zinc oxide electrodes, known for their outstanding light trapping properties, via ultraviolet nanoimprint lithography. As a result of the high electron mobility and excellent near-infrared transparency of hydrogenated indium oxide, the short-circuit current density of the cells is improved with respect to indium tin oxide and zinc oxide electrodes. We assess the potential for further current gains by identifying remaining sources of parasitic absorption and evaluate the light trapping capacity of each electrode. We further present a method, based on nonabsorbing insulating silicon nitride electrodes, allowing one to directly relate the optical reflectance to the external quantum efficiency. Our method provides a useful experimental tool to evaluate the light trapping potential of novel photonic nanostructures by a simple optical reflectance measurement, avoiding complications with electrical cell performance.

  20. Inline deposited thin-film silicon solar cells on imprinted foil

    Energy Technology Data Exchange (ETDEWEB)

    Van Aken, B.B.; Heijna, M.C.R.; Loffler, J.; Soppe, W.J. [ECN Solar Energy, P.O. Box 1, NL-1755 ZG Petten (Netherlands)

    2011-09-15

    ECN is developing n-i-p solar cells based on a-Si and {mu}c-Si absorber layers deposited with inline PECVD, using linear plasma sources, on an imprint-textured UV curable coating layer on foil. We show that solar cells deposited on foil with random texture can achieve good light trapping (J{sub sc} {approx} 15-16 mA/cm{sup 2} for a-Si cells). Furthermore, we show that a-Si nip cells on foil, processed in dynamic mode in an industrial pilot roll-to-roll system for 30 cm wide foils, can achieve efficiencies of over 7%. Future work will focus on developing and implementing optimised periodic nanotextures for {mu}c-Si and micromorph tandem.

  1. Dynamically deposited thin-film silicon solar cells on imprinted foil

    Energy Technology Data Exchange (ETDEWEB)

    Van Aken, B.B.; Heijna, M.C.R.; Loffler, J.; Soppe, W.J. [ECN Solar Energy, P.O. Box 1, NL-1755 ZG Petten (Netherlands)

    2011-12-23

    The Energy research Centre of the Netherlands (ECN) is developing n-i-p solar cells based on a-Si and {mu}c-Si absorber layers deposited with inline PECVD, using linear plasma sources, on an imprint-textured UV curable coating layer on foil. We show that solar cells deposited on foil with random texture can achieve good light trapping (Jsc {approx} 15-16 mA/cm{sup 2} for a-Si cells). Furthermore, we show that a-Si nip cells on foil, processed in dynamic mode in an industrial pilot roll-to-roll system for 30 cm wide foils, can achieve efficiencies (of over 7%). Future work will focus on developing and implementing optimised periodic nanotextures for {mu}c-Si and micromorph tandem.

  2. Multi-junction Thin-film Solar Cells on Flexible Substrates for Space Power

    Science.gov (United States)

    Hepp, Aloysius F.; Smith, Mark; Scofield, John H.; Dickman, John E.; Lush, Gregory B.; Morel, Donald L.; Ferekides, Christos; Dhere, Neelkanth G.

    2002-01-01

    The ultimate objective of the thin-film program at NASA GRC is development of a 20 percent AM0 thin-film device technology with high power/weight ratio. Several approaches are outlined to improve overall device efficiency and power/weight ratio. One approach involves the use of very lightweight flexible substrates such as polyimides (i.e., Kapton(Trademark)) or metal foil. Also, a compound semiconductor tandem device structure that can meet this objective is proposed and simulated using Analysis of Microelectronic and Photonic Structures (AMPS). AMPS modeling of current devices in tandem format indicate that AM0 efficiencies near 20 percent can be achieved. And with improvements in materials, efficiencies approaching 25 percent are achievable. Several important technical issues need to be resolved to realize these complex devices: development of a wide bandgap material with good electronic properties, development of transparent contacts, and targeting a 2-terminal device structure (with more complicated processing and tunnel junction) or 4-terminal device. Recent progress in the NASA GRC program is outlined.

  3. Ultrasonically sprayed and inkjet printed thin film electrodes for organic solar cells

    International Nuclear Information System (INIS)

    Thin film pi-conjugated poly(3,4ethylenedioxythiophene): poly(styrenesulphonate) (PEDOT:PSS) as a hole transport layer on indium tin oxide is a key element in some of the most efficient organic photovoltaic and light emitting devices to date. Films are typically deposited by spincoating, which is not readily scalable. In this paper we investigate the critical parameters for both inkjet and ultrasonic spray deposition of PEDOT:PSS thin films on commercial indium tin oxide as a potentially scalable approach to contact formation. Inkjet parameters investigated include drop spacing and substrate temperature. Ultrasonic spray coating parameters investigated include substrate temperature and solution flow rate. We also show that the ink viscosity has a Newtonian character, making it well suited for inkjet printing. Films were characterized via optical profilometry, sheet resistance and atomic force microscopy. Optimized inkjet printed and ultrasonic sprayed PEDOT:PSS films were then compared to spincast layers in a prototypical bulk heterojunction photovoltaic device employing a poly(3-hexylthiophene) and [6,6]-PCBM (6,6-phenylC61-butric acid-methyl ester) blend as the absorber. Practically all three approaches produced devices of comparable efficiency. Efficiencies were 3.6%, 3.5% and 3.3% for spin, spray and inkjet depositions respectively

  4. Thin film solar cells by selenization sulfurization using diethyl selenium as a selenium precursor

    Science.gov (United States)

    Dhere, Neelkanth G.; Kadam, Ankur A.

    2009-12-15

    A method of forming a CIGSS absorber layer includes the steps of providing a metal precursor, and selenizing the metal precursor using diethyl selenium to form a selenized metal precursor layer (CIGSS absorber layer). A high efficiency solar cell includes a CIGSS absorber layer formed by a process including selenizing a metal precursor using diethyl selenium to form the CIGSS absorber layer.

  5. Three dimensional optical modeling of amorphous silicon thin film solar cells using the finite-difference time-domain method including real randomly surface topographies

    Science.gov (United States)

    Lacombe, Jürgen; Sergeev, Oleg; Chakanga, Kambulakwao; von Maydell, Karsten; Agert, Carsten

    2011-07-01

    In this paper, modeling of light propagation in silicon thin film solar cells without using any fitting parameter is presented. The aim is to create a realistic view of the light trapping effects and of the resulting optical generation rate in the absorbing semiconductor layers. The focus is on real three dimensional systems. Our software Sentaurus tcad, developed by Synopsys, has the ability to import real topography measurements and to model the light propagation using the finite-difference time-domain method. To verify the simulation, we compared the measured and simulated angular distribution functions of a glass/SnO2:F transparent conducting oxide system for different wavelengths. The optical generation rate of charge carriers in amorphous silicon thin film solar cells including rough interfaces is calculated. The distribution of the optical generation rate is correlated with the shape of the interface, and the external quantum efficiencies are calculated and compared to experimental data.

  6. Fabrication and characterization methods for growth of CZTS as a promising material for thin film solar cells

    Science.gov (United States)

    Emrani, Amin

    Current research trends are moving towards earth-abundant and low toxicity materials. Cu2ZnSnS4 (CZTS), which consists not only earth-abundant and non-toxic elemental constituents, but also possesses a nearly optimum band gap of 1.5 eV and a high absorption coefficient, has the potential to be a leading material for large scale generation of solar energy. Although theoretical calculations estimated the feasibility of achieving an efficiency between 30 to 40 %, for CZTS solar cells, unfortunately, there is no standard approach to fabricate CZTS cells to reach an efficiency even close to these numbers. In this dissertation, several potential methods from vacuum based techniques such as sputtering to a new solution-based process to deposit CZTS films have been explored, studied and developed. To further improve the CZTS solar cell performance, other layers essential for CZTS solar cells have also been analyzed and optimized. Lastly, the performance and efficiencies of the final integrated cells are presented. First, we report a two-step process with sputtering of elemental precursors followed by sulfurization in dilute H2S. Structural and optical properties of CZTS thin films at various temperatures are studied. The CZTS films formed at 550°C exhibited a compact void-free structure yields the highest efficiency of 5.75%. Since long duration annealing processes are not practical for industry and result in the formation of voids due to the sublimation of secondary phases, fast annealing under sulfur vapor atmosphere has further been investigated. Since the H2S annealing is cleaner and more controllable than dealing with sulfur vapor pressure. We report a two-step process with sputtering of elemental precursors followed by fast sulfurization in dilute H2S. The electrical characteristics and the efficiencies of the respective solar cells were analyzed and compared. The films annealed at 580°C for 30 minutes exhibited the highest efficiency of 3.8%. Another approach to form a uniform precursor is the use of a target consisting of Zn, Sn and Cu. Here we studied the practical issues of using an alloy targets (particularly Cu-Sn alloy target) to deposit CZT layers. Although high-vacuum techniques have already shown promising results, the complex equipment required for such the processes results in costly implementation to scale up. CZTS growth by solution-based methods could potentially provide a low-cost alternative method to fabricate CZTS solar cells in large scale. Here, we introduced and developed a new non-toxic solution-based method to deposit CZTS. Efficiencies of 1.3% have been achieved up to now.

  7. Nanostructured three-dimensional thin film silicon solar cells with very high efficiency potential

    Science.gov (United States)

    Vanecek, Milan; Babchenko, Oleg; Purkrt, Adam; Holovsky, Jakub; Neykova, Neda; Poruba, Ales; Remes, Zdenek; Meier, Johannes; Kroll, Ulrich

    2011-04-01

    We report on the experimental realization of amorphous/microcrystalline silicon tandem solar cells (Micromorph) based on our three-dimensional design. An enhancement is reached in the short-circuit current by 40%, with an excellent open-circuit voltage of 1.41V and a fill factor of 72%. We have used nanoholes or microholes dry etched into the ZnO front contact layer. Monte Carlo optical modeling shows that stable efficiency of amorphous silicon p-i-n solar cells in over 12% range is possible. For the Micromorph cells, efficiency over 15% with the thickness of amorphous Si below 200 nm and of microcrystalline Si around 500 nm is possible.

  8. A NOVEL LOW THERMAL BUDGET THIN-FILM POLYSILICON FABRICATION PROCESS FOR LARGE-AREA, HIGH-THROUGHPUT SOLAR CELL PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Yue Kuo

    2010-08-15

    A novel thin-film poly-Si fabrication process has been demonstrated. This low thermal budget process transforms the single- and multi-layer amorphous silicon thin films into a poly-Si structure in one simple step over a pulsed rapid thermal annealing process with the enhancement of an ultrathin Ni layer. The complete poly-Si solar cell was fabricated in a short period of time without deteriorating the underneath glass substrate. The unique vertical crystallization process including the mechanism is discussed. Influences of the dopant type and process parameters on crystal structure will be revealed. The poly-Si film structure has been proved using TEM, XRD, Raman, and XPS methods. The poly-Si solar cell structure and the performance have been examined. In principle, the new process is potentially applicable to produce large-area thin-film poly-Si solar cells at a high throughput and low cost. A critical issue in this process is to prevent the excessive dopant diffusion during crystallization. Process parameters and the cell structure have to be optimized to achieve the production goal.

  9. High-temperature CVD processes for crystalline silicon thin-film and wafer solar cells

    OpenAIRE

    Schmich, Evelyn Karin

    2008-01-01

    In this thesis, novel in-situ CVD processes have been investigated that promise to decrease the costs and increase cell efficiencies at the same time. The central approach is the epitaxial wafer-equivalent cell structure, consisting of an epitaxial layer deposited on a low-cost silicon substrate. This epitaxial wafer-equivalent (EpiWE) is then processed using a standard solar cell process. The main goal of this thesis project was to improve the quality and the electrical properties of the dep...

  10. Optimal design of one-dimensional photonic crystal back reflectors for thin-film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Peizhuan; Hou, Guofu, E-mail: gfhou@nankai.edu.cn; Zhang, Jianjun, E-mail: jjzhang@nankai.edu.cn; Zhang, Xiaodan; Zhao, Ying [Institute of Photoelectronics and Tianjin Key Laboratory of Photoelectronic Thin-film Devices and Technique, Nankai University, Tianjin 300071 (China)

    2014-08-14

    For thin-film silicon solar cells (TFSC), a one-dimensional photonic crystal (1D PC) is a good back reflector (BR) because it increases the total internal reflection at the back surface. We used the plane-wave expansion method and the finite difference time domain (FDTD) algorithm to simulate and analyze the photonic bandgap (PBG), the reflection and the absorption properties of a 1D PC and to further explore the optimal 1D PC design for use in hydrogenated amorphous silicon (a-Si:H) solar cells. With identified refractive index contrast and period thickness, we found that the PBG and the reflection of a 1D PC are strongly influenced by the contrast in bilayer thickness. Additionally, light coupled to the top three periods of the 1D PC and was absorbed if one of the bilayers was absorptive. By decreasing the thickness contrast of the absorptive layer relative to the non-absorptive layer, an average reflectivity of 96.7% was achieved for a 1D PC alternatively stacked with a-Si:H and SiO{sub 2} in five periods. This reflectivity was superior to a distributed Bragg reflector (DBR) structure with 93.5% and an Ag film with 93.4%. n-i-p a-Si:H solar cells with an optimal 1D PC-based BR offer a higher short-circuit current density than those with a DBR-based BR or an AZO/Ag-based BR. These results provide new design rules for photonic structures in TFSC.

  11. Optimal design of one-dimensional photonic crystal back reflectors for thin-film silicon solar cells

    Science.gov (United States)

    Chen, Peizhuan; Hou, Guofu; Zhang, Jianjun; Zhang, Xiaodan; Zhao, Ying

    2014-08-01

    For thin-film silicon solar cells (TFSC), a one-dimensional photonic crystal (1D PC) is a good back reflector (BR) because it increases the total internal reflection at the back surface. We used the plane-wave expansion method and the finite difference time domain (FDTD) algorithm to simulate and analyze the photonic bandgap (PBG), the reflection and the absorption properties of a 1D PC and to further explore the optimal 1D PC design for use in hydrogenated amorphous silicon (a-Si:H) solar cells. With identified refractive index contrast and period thickness, we found that the PBG and the reflection of a 1D PC are strongly influenced by the contrast in bilayer thickness. Additionally, light coupled to the top three periods of the 1D PC and was absorbed if one of the bilayers was absorptive. By decreasing the thickness contrast of the absorptive layer relative to the non-absorptive layer, an average reflectivity of 96.7% was achieved for a 1D PC alternatively stacked with a-Si:H and SiO2 in five periods. This reflectivity was superior to a distributed Bragg reflector (DBR) structure with 93.5% and an Ag film with 93.4%. n-i-p a-Si:H solar cells with an optimal 1D PC-based BR offer a higher short-circuit current density than those with a DBR-based BR or an AZO/Ag-based BR. These results provide new design rules for photonic structures in TFSC.

  12. Optimal design of one-dimensional photonic crystal back reflectors for thin-film silicon solar cells

    International Nuclear Information System (INIS)

    For thin-film silicon solar cells (TFSC), a one-dimensional photonic crystal (1D PC) is a good back reflector (BR) because it increases the total internal reflection at the back surface. We used the plane-wave expansion method and the finite difference time domain (FDTD) algorithm to simulate and analyze the photonic bandgap (PBG), the reflection and the absorption properties of a 1D PC and to further explore the optimal 1D PC design for use in hydrogenated amorphous silicon (a-Si:H) solar cells. With identified refractive index contrast and period thickness, we found that the PBG and the reflection of a 1D PC are strongly influenced by the contrast in bilayer thickness. Additionally, light coupled to the top three periods of the 1D PC and was absorbed if one of the bilayers was absorptive. By decreasing the thickness contrast of the absorptive layer relative to the non-absorptive layer, an average reflectivity of 96.7% was achieved for a 1D PC alternatively stacked with a-Si:H and SiO2 in five periods. This reflectivity was superior to a distributed Bragg reflector (DBR) structure with 93.5% and an Ag film with 93.4%. n-i-p a-Si:H solar cells with an optimal 1D PC-based BR offer a higher short-circuit current density than those with a DBR-based BR or an AZO/Ag-based BR. These results provide new design rules for photonic structures in TFSC

  13. Rapid Thermal Annealing and Hydrogen Passivation of Polycrystalline Silicon Thin-Film Solar Cells on Low-Temperature Glass

    Directory of Open Access Journals (Sweden)

    Armin G. Aberle

    2007-12-01

    Full Text Available The changes in open-circuit voltage (Voc, short-circuit current density (Jsc, and internal quantum efficiency (IQE of aLuminum induced crystallization, ion-assisted deposition (ALICIA polycrystalline silicon thin-film solar cells on low-temperature glass substrates due to rapid thermal anneal (RTA treatment and subsequent remote microwave hydrogen plasma passivation (hydrogenation are examined. Voc improvements from 130 mV to 430 mV, Jsc improvements from 1.2 mA/cm2 to 11.3 mA/cm2, and peak IQE improvements from 16% to > 70% are achieved. A 1-second RTA plateau at 1000°C followed by hydrogenation increases the Jsc by a factor of 5.5. Secondary ion mass spectroscopy measurements are used to determine the concentration profiles of dopants, impurities, and hydrogen. Computer modeling based on simulations of the measured IQE data reveals that the minority carrier lifetime in the absorber region increases by 3 orders of magnitude to about 1 nanosecond (corresponding to a diffusion length of at least 1 μm due to RTA and subsequent hydrogenation. The evaluation of the changes in the quantum efficiency and Voc due to RTA and hydrogenation with computer modeling significantly improves the understanding of the limiting factors to cell performance.

  14. Physical properties of disordered Chalcogenide solar cell from Pb20GexSe80-x thin films

    International Nuclear Information System (INIS)

    The preparation and study of homogeneous p-n junctions from amorphous chalcogenide Pb20GexSe80-x by thermal evaporation are presented. Such p-n junction is a novel module since no one had fabricated such homogeneous cell from these amorphous compounds yet. The p-type layer is Pb20Ge20Se60 and the n-type is Pb20Ge25Se55 elemental analysis of n- and p-types of Pb20GexSe80-x is confirmed by energy dispersive X-ray analysis. Optical energy gaps were determined from transmission spectra in the range of 300 to 2500 nm; these values was 1.9 eV for p-Pb20Ge20Se60 and 2.0 eV for n-Pb20Ge25Se55 thin films. The J-V characteristics in the dark are exhibited rectification in the reverse voltage resulting from junction. The reverse current under illumination shows no saturation with voltage. From I-V characteristics under illumination and the spectral response the open circuit voltage Voc and Isc were measured. Capacitance measurements are the main method to evaluate doping concentration through the solar cell. The distribution of charged carriers across the depletion region was calculated and interpreted. (authors)

  15. GaAs CLEFT solar cells for space applications. [CVD thin film growth technology

    Science.gov (United States)

    Fan, J. C. C.; Mcclelland, R. W.; King, B. D.

    1984-01-01

    Although GaAs solar cells are radiation-resistant and have high conversion efficiencies, there are two major obstacles that such cells must overcome before they can be widely adopted for space applications: GaAs wafers are too expensive and cells made from these wafers are too heavy. The CLEFT process permits the growth of thin single-crystal films on reusable substrates, resulting in a drastic reduction in both cell cost and cell weight. Recent advances in CLEFT technology have made it possible to achieve efficiencies of about 14 percent AM0 for 0.51-sq cm GaAs solar cells 5 microns thick with a 41-mil-thick coverglass. In preliminary experiments efficiencies close to 19 percent AM1 have been obtained for 10-micron-thick cells. It is suggested that the CLEFT technology should yield inexpensive, highly efficient modules with a beginning-of-life specific power close to 1 kW/kg (for a coverglass thickness of 4 mils).

  16. SnX (X = S, Se) thin films as cost-effective and highly efficient counter electrodes for dye-sensitized solar cells.

    Science.gov (United States)

    Liu, Feng; Zhu, Jun; Xu, Yafeng; Zhou, Li; Li, Yi; Hu, Linhua; Yao, Jianxi; Dai, Songyuan

    2015-05-11

    Solution-deposited SnSe and SnS thin films demonstrate excellent electrocatalytic activity toward the triiodide reduction in dye-sensitized solar cells (DSCs), even better than that of the conventional noble Pt electrode used in DSCs. An enhanced photovoltaic efficiency with the maximum value of 9.4% was thus achieved, higher than that with Pt (9.0%). PMID:25869882

  17. Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se2 thin-film solar cell absorbers

    Science.gov (United States)

    Lehmann, Jascha; Lehmann, Sebastian; Lauermann, Iver; Rissom, Thorsten; Kaufmann, Christian A.; Lux-Steiner, Martha Ch.; Bär, Marcus; Sadewasser, Sascha

    2014-12-01

    Currently, Cu-containing chalcopyrite-based solar cells provide the highest conversion efficiencies among all thin-film photovoltaic (PV) technologies. They have reached efficiency values above 20%, the same performance level as multi-crystalline silicon-wafer technology that dominates the commercial PV market. Chalcopyrite thin-film heterostructures consist of a layer stack with a variety of interfaces between different materials. It is the chalcopyrite/buffer region (forming the p-n junction), which is of crucial importance and therefore frequently investigated using surface and interface science tools, such as photoelectron spectroscopy and scanning probe microscopy. To ensure comparability and validity of the results, a general preparation guide for "realistic" surfaces of polycrystalline chalcopyrite thin films is highly desirable. We present results on wet-chemical cleaning procedures of polycrystalline Cu(In1-xGax)Se2 thin films with an average x = [Ga]/([In] + [Ga]) = 0.29, which were exposed to ambient conditions for different times. The hence natively oxidized sample surfaces were etched in KCN- or NH3-based aqueous solutions. By x-ray photoelectron spectroscopy, we find that the KCN treatment results in a chemical surface structure which is - apart from a slight change in surface composition - identical to a pristine as-received sample surface. Additionally, we discover a different oxidation behavior of In and Ga, in agreement with thermodynamic reference data, and we find indications for the segregation and removal of copper selenide surface phases from the polycrystalline material.

  18. Spray deposition and characterization of nanostructured Li doped NiO thin films for application in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Transparent conducting Li (0-5 wt%) doped NiO thin films with preferential growth along the (111) plane were deposited onto glass substrates by pyrolytic decomposition of nickel nitrate and lithium chloride precursors at 500 deg. C in air. The effect of Li concentration on the structural, optical and transport properties of NiO thin films was studied by x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), spectral transmittance, photoluminescence and linear four-probe resistivity. Activation energies as a function of Li concentration were deduced from the temperature dependent resistivity data measured in the range 300-448 K. The figure of merit was deduced by combining the spectral transmittance and sheet resistance values. The variation in properties of NiO thin film due to Li doping are discussed based on the above results. A dye-sensitized solar cell has also been fabricated for the optimized Li doped NiO thin film and the results are presented.

  19. High-performance a-SiGe:H thin