WorldWideScience
1

Silicon Thin-Film Solar Cells  

OpenAIRE

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...

Guy Beaucarne

2007-01-01

2

Advances in thin-film solar cells  

CERN Document Server

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

Dharmadasa, I M

2012-01-01

3

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)

4

Silicon Thin-Film Solar Cells  

Directory of Open Access Journals (Sweden)

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.

Guy Beaucarne

2007-12-01

5

Thin-film solar cells: an overview  

Energy Technology Data Exchange (ETDEWEB)

Thin film solar cells (TFSC) are a promising approach for terrestrial and space photovoltaics and offer a wide variety of choices in terms of the device design and fabrication. A variety of substrates (flexible or rigid, metal or insulator) can be used for deposition of different layers (contact, buffer, absorber, reflector, etc.) using different techniques (PVD, CVD, ECD, plasma-based, hybrid, etc.). Such versatility allows tailoring and engineering of the layers in order to improve device performance. For large-area devices required for realistic applications, thin-film device fabrication becomes complex and requires proper control over the entire process sequence. Proper understanding of thin-film deposition processes can help in achieving high-efficiency devices over large areas, as has been demonstrated commercially for different cells. Research and development in new, exotic and simple materials and devices, and innovative, but simple manufacturing processes need to be pursued in a focussed manner. Which cell(s) and which technologies will ultimately succeed commercially continue to be anybody's guess, but it would surely be determined by the simplicity of manufacturability and the cost per reliable watt. Cheap and moderately efficient TFSC are expected to receive a due commercial place under the sun. (author)

Chopra, K.L.; Dutta, V. [Indian Inst. of Technology, New Delhi (India). Photovolatic Lab.; Paulson, P.D. [Institute of Energy Conversion, Newark, Delaware (United States)

2004-07-01

6

Transparent conductive oxides for thin-film silicon solar cells  

OpenAIRE

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...

Lo?ffler, J.

2005-01-01

7

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

International Nuclear Information System (INIS)

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

8

Thin Film Solar Cells: Research in an Industrial Perspective  

OpenAIRE

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...

Edoff, Marika

2012-01-01

9

Copper zinc tin sulfide-based thin film solar cells  

CERN Document Server

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

Ito, Kentaro

2014-01-01

10

UV imprinting for thin film solar cell application  

OpenAIRE

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.

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

2012-01-01

11

Silver nanowire composite thin films as transparent electrodes for Cu(In,Ga)Se?/ZnS thin film solar cells.  

Science.gov (United States)

Solution processed silver nanowire indium-tin oxide nanoparticle (AgNW-ITONP) composite thin films were successfully applied as the transparent electrodes for Cu(In,Ga)Se? (CIGS) thin film solar cells with ZnS buffer layers. Properties of the AgNW-ITONP thin film and its effects on performance of CIGS/ZnS thin film solar cells were studied. Compared with the traditional sputtered ITO electrodes, the AgNW-ITONP thin films show comparable optical transmittance and electrical conductivity. Furthermore, the AgNW-ITONP thin film causes no physical damage to the adjacent surface layer and does not need high temperature annealing, which makes it very suitable to use as transparent conductive layers for heat or sputtering damage-sensitive optoelectronic devices. By using AgNW-ITONP electrodes, the required thickness of the ZnS buffer layers for CIGS thin film solar cells was greatly decreased. PMID:24922214

Tan, Xiao-Hui; Chen, Yu; Liu, Ye-Xiang

2014-05-20

12

Thin film solar cells and their optical properties  

OpenAIRE

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 ...

Stanislav Jurecka; Emil Pincik; Robert Brunner

2006-01-01

13

Single Source Precursors for Thin Film Solar Cells  

Science.gov (United States)

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.

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

2002-01-01

14

Indium tin oxide-silicon thin film solar cell  

International Nuclear Information System (INIS)

Heterojunction solar cells consisting of amorphous indium tin oxide (ITO) thin films on silicon films have been fabricated and studied. The results show that the devices give a photovoltaic effect and rectifying characteristics. One of the main characteristics of amorphous ITO thin films is better transparency (>85%) over the complete useful window of the solar spectrum. The polarity observed is found to be consistent with V/sub oc/ = 0.34 volt, I/sub sc/ = 22mA/cm/sup 2/ and fill factor = 0.48. An attempt has been made to understand the conduction mechanism of indium tin oxide - silicon heterojunction

15

Thin Film Solar Cells and their Optical Properties  

Directory of Open Access Journals (Sweden)

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.

Robert Brunner

2006-01-01

16

Low cost thin film poly-silicon solar cells  

Energy Technology Data Exchange (ETDEWEB)

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.

NONE

2005-07-01

17

Testing and failure analysis of thin film solar cells  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-10-15

18

Polycrystalline thin-film solar cells and modules  

Energy Technology Data Exchange (ETDEWEB)

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

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

1991-12-01

19

Thin-film silicon solar cell technology.  

Czech Academy of Sciences Publication Activity Database

Ro?. 12, - (2004), s. 113-142. ISSN 1062-7995 R&D Projects: GA MP 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

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

2004-01-01

20

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

OpenAIRE

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

Schropp, R. E. I.

2012-01-01

21

TCAD simulations for thin film solar cells with nanoplate structures.  

Science.gov (United States)

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

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

2012-07-01

22

CZTSSe thin film solar cells: Surface treatments  

Science.gov (United States)

Chalcopyrite semiconducting materials, specifically CZTS, are a promising alternative to traditional silicon solar cell technology. Because of the high absorption coefficient; films of the order of 1 micrometer thickness are sufficient for the fabrication of solar cells. Liquid based synthesis methods are advantageous because they are easily scalable using the roll to roll manufacturing techniques. Various treatments are explored in this study to enhance the performance of the selenized CZTS film based solar cells. Thiourea can be used as a sulfur source and can be used to tune band gap of CZTSSe. Bromine etching can be used to manipulate the thickness of sintered CZTSSe film. The etching treatment creates recombination centers which lead to poor device performance. Various after treatments were used to improve the performance of the devices. It was observed that the performance of the solar cell devices could not be improved by any of the after treatment steps. Other surface treatment processes are explored including KCN etching and gaseous H2S treatments. Hybrid solar cells which included use of CIGS nanoparticles at the interface between CZTSSe and CdS are also explored.

Joglekar, Chinmay Sunil

23

Photovoltaic technology: the case for thin-film solar cells  

Science.gov (United States)

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 example, to the roll-to-roll production possibilities for modules. Recent developments suggest that thin-film crystalline silicon (especially microcrystalline silicon) is becoming a prime candidate for future photovoltaics. PMID:10426984

Shah; Torres; Tscharner; Wyrsch; Keppner

1999-07-30

24

Thin-film polycrystalline silicon solar cells  

Science.gov (United States)

Twenty eight diffused junction solar cells were prepared. The largest group consisted of cells fabricated on bicrystal wafers and their single crystal controls. Cells were made on two different substrate types, ribbon silicon and cast silicon. The ribbon cells had an average efficiency of 6.1 percent, while the cast silicon cells had an average efficiency of 8.9 percent. A technique for observing grain boundaries was developed, i.e., the laser scan photoconductivity technique. In this method grain boundaries in bare silicon are observed by applying a small dc voltage across either end of a rectangular silicon bar. When the light spot crosses the grain boundary a large signal is observed. This method is useful for studying atomic hydrogen passivation, since a diffused junction is unnecessary. The liquid crystal method of observing grain boundaries is discussed. No correlation is found between grain boundary electrical activity and crystallographic orientation of the grains.

Faughnan, B. W.; Blanc, J.; Phillips, W.; Redfield, D.

1980-06-01

25

Nanowired Polymer Thin Film Solar Cells  

OpenAIRE

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.

Dr K Siddappa Naidu, Dr D. Bhattacharya

2013-01-01

26

Nanowired Polymer Thin Film Solar Cells  

Directory of Open Access Journals (Sweden)

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.

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

2013-12-01

27

TCOs for nip thin film silicon solar cells  

OpenAIRE

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 (c-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...

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

2009-01-01

28

Transparent conductive oxides for thin-film silicon solar cells  

Science.gov (United States)

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 150 C and 350 C, 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.

Lffler, J.

2005-04-01

29

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

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

Kodigala, Subba Ramaiah

2013-01-01

30

Laser annealing of thin film polycrystalline silicon solar cell  

Directory of Open Access Journals (Sweden)

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.

Chowdhury A.

2013-11-01

31

Transparent conducting oxide layers for thin film silicon solar cells  

OpenAIRE

Texture etching of ZnO:1%Al layers using diluted HCl solution provides excellent TCOs with crater type surface features for the front contact of superstrate type of thin film silicon solar cells. The texture etched ZnO:Al definitely gives superior performance than Asahi SnO2:F TCO in case of nanocrystalline silicon (nc-Si) type of solar cells. The stress of the ZnO:Al film changes from tensile to compressive with the increase in substrate temperature of sputter deposition and the rms roughnes...

Rath, J. K.; Liu, Y.; Jong, M. M.; Wild, J.; Schuttauf, J. A.; Brinza, M.; Schropp, R. E. I.

2010-01-01

32

Thin film solar cell including a spatially modulated intrinsic layer  

Science.gov (United States)

One or more thin film solar cells in which the intrinsic layer of substantially amorphous semiconductor alloy material thereof includes at least a first band gap portion and a narrower band gap portion. The band gap of the intrinsic layer is spatially graded through a portion of the bulk thickness, said graded portion including a region removed from the intrinsic layer-dopant layer interfaces. The band gap of the intrinsic layer is always less than the band gap of the doped layers. The gradation of the intrinsic layer is effected such that the open circuit voltage and/or the fill factor of the one or plural solar cell structure is enhanced.

Guha, Subhendu (Troy, MI); Yang, Chi-Chung (Troy, MI); Ovshinsky, Stanford R. (Bloomfield Hills, MI)

1989-03-28

33

Ultra-thin film nanostructured gallium arsenide solar cells  

Science.gov (United States)

State-of-the-art III-V cells have reached the highest energy conversion efficiency among all types of solar cells. However, these cells are not applicable to widespread terrestrial solar energy system yet due to the high cost of epitaxial growth. Ultra-thin film absorbers with advanced light management is one of the most promising solutions to drive down the cost. In this paper, we present an ultra-thin film nano-window gallium arsenide (GaAs) solar cell design. This ultrathin cell consists of a nano-structured Al0.8Ga0.2As window layer on the front side to reduce the reflection and to trap the light, and a metal reflector on the back side to further increase the light path. The 300 nm thick GaAs cell with Al0.8Ga0.2As nano-window shows a broad band absorption enhancement from visible to near infrared (NIR), achieving a spectrally averaged absorption of 94% under normal incidence. In addition, this cell shows excellent angular absorption properties, achieving over 85% spectral averaged absorption at up to 60 degree off normal incidence. Meanwhile, this structure with planar junction and nano-window has solved the issue of low fill factor and low open-circuit voltage in nano-structured GaAs solar cell. A nano-window cell with a 3 ?m thick GaAs junction demonstrated an open circuit voltage of 0.9V.

Kang, Yangsen; Chen, Yusi; Huo, Yijie; Zhao, Li; Jia, Jieyang; Deng, Huiyang; Harris, James S.

2014-11-01

34

Efficient optical absorption in thin-film solar cells.  

Science.gov (United States)

In order to improve the optical absorption of hydrogenated amorphous silicon (a-Si:H) thin film solar cells, a new structure consisted of ITO layer with the nonresonant nanoparticles embedded in it and a-Si:H layer, is proposed. By optimizing both the thickness of a-Si:H layer and nanoparticles size, the effects of Fabry-Perot resonance and the scattering of incident light are discussed and analyzed. It is demonstrated that the enhanced optical absorption can be achieved due to the coupling of incident light and nanostructure, simultaneously the proposed structure can be considered as gradient refractive index structure to restrain the reflection at the interface of ITO and a-Si:H thin film. PMID:21935260

Yang, Lili; Xuan, Yimin; Tan, Junjie

2011-09-12

35

Modeling of laser patterning of thin-film solar cells  

Science.gov (United States)

We report on theoretical models of the interaction of ultra-short laser pulses with multilayer structures used in thin-film solar cells. A finite-difference based optical model of light propagation within the thin-film system is used to determine the 3D-distribution of absorbed laser power in the structure. The model includes the evolution of the density of charge carriers which may be driven either by direct absorption of the laser radiation or multi-photon absorption and impact ionization of highly excited carriers. Depending on the excitation wavelength and pulse energy absorption occurs in different depths of the structure which has a large effect on the efficiency of the laser ablation process.

Peschel, Thomas; Matthus, G.; Nolte, S.; Eberhardt, R.; Tnnermann, A.

2014-03-01

36

Methods for fabricating thin film III-V compound solar cell  

Science.gov (United States)

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.

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

2011-08-09

37

New 3-dimensional nanostructured thin film silicon solar cells.  

Czech Academy of Sciences Publication Activity Database

Mnchen : 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 Mk(CZ) 7E09057 Grant ostatn: 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

Van??ek, Milan; Neykova, Neda; Babchenko, Oleg; Purkrt, Adam; Poruba, Ale; Reme, Zden?k; Holovsk, Jakub; Hruka, Karel; Meier, J.; Kroll, U.

38

Thin Film Solar Cells: Organic, Inorganic and Hybrid  

Science.gov (United States)

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.

Dankovich, John

2004-01-01

39

Silver Nanoparticle Enhanced Freestanding Thin-Film Silicon Solar Cells  

Science.gov (United States)

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

Winans, Joshua David

40

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

41

Thin film CdS/CdTe solar cells  

Science.gov (United States)

The effects of processes used in making thin film ITO/CdS/CdTe/Au heterojunction solar cells have been investigated. In particular, air annealing the ITO/CdS/CdTe layer is shown, from spectral evidence, to produce a heterojunction. XPS evidence shows that this heating forms CdO and TeO 2 on the CdTe surface and that these are removed by a KOH etch. A further bromine/methanol etch leaves a Te-rich surface which forms an injecting contact with the Au top electrode into which the Te mixes.

Danaher, W. J.; Lyons, L. E.; Morris, G. C.

1985-05-01

42

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

Directory of Open Access Journals (Sweden)

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.

???

2011-03-01

43

Earth abundant materials for high efficiency heterojunction thin film solar cells  

OpenAIRE

We investigate earth abundant materials for thin-film solar cells that can meet tens of terawatts level deployment potential. Candidate materials are identified by combinatorial search, large-scale electronic structure calculations, and literature reviews. We identified cuprous oxide (Cu2O) as a prototype candidate for investigation as an absorber layer in thin film solar cells. Cu2O thin films are deposited by reactive DC magnetron sputtering and characterized. In order to tailor electrical ...

Buonassisi, Tonio; Bertoni, Mariana I.; Chan, Maria K.; Ceder, Gerbrand; Lee, Yun Seog

2009-01-01

44

Laser structuring of thin-film solar cells on polymers  

OpenAIRE

Abstract A permanent growth of the thin-film electronics market stimulates the development of versatile technologies for patterning thin-film materials on flexible substrates. High repetition rate lasers with a short pulse duration offer new possibilities for high efficiency structuring of conducting, semi-conducting and isolating films. Lasers with the picosecond pulse duration were applied in structuring the complex multilayered Cu(InGa)Se (CIGS) solar cel...

Gec?ys, P.; Rac?iukaitis, G.; Gedvilas, M.; Selskis, A.

2009-01-01

45

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

46

Commercial Development Of Ovonic Thin Film Solar Cells  

Science.gov (United States)

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

Ovshinsky, Stanford R.

1983-09-01

47

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

Science.gov (United States)

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.

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

2014-09-01

48

Thin-film CdS/CdTe solar cells  

International Nuclear Information System (INIS)

A thin-film solar cell with the configuration soda-lime glass ITO/CdS/CdTe/Au was reported earlier to have more than 10% conversion efficiency. To further improve the low-cost potential of the device, an SnO/sub 2/ layer was developed to replace ITO, and a new contact to CdTe using Ni or stainless steel to replace Au. The contact also improves the stability of the device. A low-cost method for monolithic integration of these cells to make a module is discussed. By this method, a module of 32 cm/sup 2/ area and 8.5% efficiency was fabricated. A simple and effective ''cross-cut'' method for minimizing the effects of shorting defects is also described

49

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

Science.gov (United States)

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.

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

2014-09-01

50

Potential of thin-film solar cell module technology  

Science.gov (United States)

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.

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

1985-01-01

51

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.

52

Cuinse2 Thin Film For Solar Cell By Flash Evaporation  

Directory of Open Access Journals (Sweden)

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

A.H. Soepardjo

2009-11-01

53

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.

54

Nano-photonic Light Trapping In Thin Film Solar Cells  

Science.gov (United States)

Over the last several decades there have been significant advances in the study and understanding of light behavior in nanoscale geometries. Entire fields such as those based on photonic crystals, plasmonics and metamaterials have been developed, accelerating the growth of knowledge related to nanoscale light manipulation. Coupled with recent interest in cheap, reliable renewable energy, a new field has blossomed, that of nanophotonic solar cells. In this thesis, we examine important properties of thin-film solar cells from a nanophotonics perspective. We identify key differences between nanophotonic devices and traditional, thick solar cells. We propose a new way of understanding and describing limits to light trapping and show that certain nanophotonic solar cell designs can have light trapping limits above the so called ray-optic or ergodic limit. We propose that a necessary requisite to exceed the traditional light trapping limit is that the active region of the solar cell must possess a local density of optical states (LDOS) higher than that of the corresponding, bulk material. Additionally, we show that in addition to having an increased density of states, the absorber must have an appropriate incoupling mechanism to transfer light from free space into the optical modes of the device. We outline a portfolio of new solar cell designs that have potential to exceed the traditional light trapping limit and numerically validate our predictions for select cases. We emphasize the importance of thinking about light trapping in terms of maximizing the optical modes of the device and efficiently coupling light into them from free space. To further explore these two concepts, we optimize patterns of superlattices of air holes in thin slabs of Si and show that by adding a roughened incoupling layer the total absorbed current can be increased synergistically. We suggest that the addition of a random scattering surface to a periodic patterning can increase incoupling by lifting the constraint of selective mode occupation associated with periodic systems. Lastly, through experiment and simulation, we investigate a potential high efficiency solar cell architecture that can be improved with the nanophotonic light trapping concepts described in this thesis. Optically thin GaAs solar cells are prepared by the epitaxial liftoff process by removal from their growth substrate and addition of a metallic back reflector. A process of depositing large area nano patterns on the surface of the cells is developed using nano imprint lithography and implemented on the thin GaAs cells.

Callahan, Dennis M., Jr.

55

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

OpenAIRE

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 10ps 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...

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

2010-01-01

56

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

57

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

58

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

OpenAIRE

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...

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

2012-01-01

59

Enhanced light trapping in realistic thin film solar cells using one-dimensional gratings  

OpenAIRE

Finding the optimal structure to enhance light trapping in thin film silicon solar cells has attracted much attention in the previous decades. However, because of problems in integrating theory and experiment, there are only few comprehensive contributions that provide guidelines for the optimal design of such structures. In this work, a realistic thin film solar cell with almost conformal layers based on a one-dimensional metallic grating back-reflector is investigated through experiment and...

Naqavi, A.; Soederstroem, K.; Haug, F. -j; Paeder, V.; Scharf, T.; Herzig, H. P.; Ballif, C.

2011-01-01

60

Understanding of photocurrent enhancement in real thin film solar cells: towards optimal onedimensional gratings  

OpenAIRE

Despite the progress in the engineering of structures to enhance photocurrent in thin film solar cells, there are few comprehensive studies which provide general and intuitive insight into the problem of light trapping. Also, lack of theoretical propositions which are consistent with fabrication is an issue to be improved. We investigate a real thin film solar cell with almost conformal layers grown on a 1D grating metallic backreflector both experimentally and theoretically. Photocurrent inc...

Naqavi, Ali; So?derstro?m, Karin; Paeder, Vincent; Scharf, Toralf; Herzig, Hans Peter; Ballif, Christophe

2011-01-01

61

Environmental influences on the performance of thin film solar cells  

International Nuclear Information System (INIS)

The response of thin film photovoltaic devices to changes in the environment is not well understood. There are a large number of conflicting reports, reflecting largely the superimposed nature of the environmental effects. A separation of the effects is not often attempted mainly because of the lack of appropriate spectral data. An experimental system has been designed and operated to facilitate the separation of the environmental effects, including spectral effects. This involves measurements in a controlled laboratory environment as well as outdoor monitoring. Furthermore, a number of analysis tools have been developed and tested for their suitability. In order to develop a system model, the applicability of parametric models for thin film devices is probed. The thermal variation of the underlying physical parameters is investigated and problems of describing thin film devices with parametric models are discussed. It is shown that the magnitude of the spectral effects for thin film devices is potentially much more significant than for conventional crystalline silicon devices. This analysis is centred on the primary spectral effect, i.e. it is conducted purely on the basis of available light and does not consider any absorption profiles or device structures. It is also shown that there is a strong daily and seasonal variation in the fraction of the useful light for devices employing a larger band gap. Environmental effects are observed directly from outdoor measuremee observed directly from outdoor measurements. It is apparent that many of the reported idiosyncrasies occurring during the operation of thin film devices can be explained simply by including spectral effects. It is possible to show the secondary spectral effect for multi-junction devices, i.e. an effect that depends on the composition of the solar irradiance and not purely on the magnitude of spectrally useful irradiance. This effect impacts mainly on the short circuit current and to some extent on the fill factor. Finally, the findings of this work are brought together in a simulation code for thin film photovoltaic devices. It is shown that it is possible to simulate such a photovoltaic system using parametric models, as long as the spectrum is considered. This is used to investigate the operational losses for one particular device. (author)

62

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

Science.gov (United States)

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.

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

1989-01-01

63

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

Energy Technology Data Exchange (ETDEWEB)

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 CuInSe2. 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. CuInSe2 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.

Landis, G.A.; Bailey, S.G.; Flood, D.J.

1989-01-01

64

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

Science.gov (United States)

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).

Landis, Geoffrey A.

1991-01-01

65

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

OpenAIRE

The paper describes the way to transfer process technology of state-of-the-art high efficiency thin film silicon solar cells fabrication on cheap plastic (such as PET or PEN) substrates, by two completely different approaches: (i) by transfer process (Helianthos concept) of thin film silicon cells deposited at high substrate temperature, Ts (200 C) and (ii) direct deposition on temperature sensitive substrates at low Ts (100 C). Adaptation of the process parameters and cell processing to ...

Rath, J. K.; Brinza, M.; Liu, Y.; Borreman, A.; Schropp, R. E. I.

2010-01-01

66

Molybdenum Back-Contact Optimization for CIGS Thin Film Solar Cell  

Directory of Open Access Journals (Sweden)

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.

J.R. Ray

2011-01-01

67

Nanosized Structural Anti-Reflection Layer for Thin Film Solar Cells  

Science.gov (United States)

A nanosized pattern layer was formed on the front surface (glass side) of the thin film solar cell using nanoimprint lithography with a Ni based moth-eye imprint mold in order to increase the total conversion efficiency of the amorphous silicon based thin film solar cell. The imprinted pattern layer had nanosized protrusions, which suppressed the reflection of light on the glass surfaces. The nanopatterns were formed using a methacryloxypropyl terminated poly(dimethylsiloxane) (MPDMS) based hard polymeric resin. The reflectance of the thin film solar cell significantly decreased because of the nanosized structural anti-reflection layer, and the total conversion efficiency of the cell increased about 3% compared to the identical solar cell without the nanosized pattern layer. Moreover, the surface exhibited a hydrophobic nature because of the surface nanopatterns and the self-assembled monolayer coating, and this hydrophobicity provided the solar cell with a self-cleaning functionality.

Han, Kang-Soo; Shin, Ju-Hyeon; Kim, Kang-In; Lee, Heon

2011-02-01

68

Polycrystalline silicon thin-film solar cell prepared by the solid phase crystallization (SPC) method  

Energy Technology Data Exchange (ETDEWEB)

A solid phase crystallization (SPC) method was applied to the fabrication of thin-film polycrystalline silicon (poly-Si) for solar cells for the first time. Among crystalline silicon solar cells crystallized at a low temperature of less than 600 C, the world`s highest conversion efficiency of 8.5% was achieved in a solar cell using thin-film poly-Si with only 10 {micro}m thickness prepared by the SPC method. This solar cell showed high photosensitivity in the long-wavelength region of more than 800 nm and also exhibited no light-induced degradation after light exposure.

Baba, T.; Matsuyama, T.; Sawada, T.; Takahama, T.; Wakisaka, K.; Tsuda, S.; Nakano, S. [Sanyo Electric Co., Ltd., Hirakata, Osaka (Japan). New Materials Research Center

1994-12-31

69

Molybdenum back-contact optimization for CIGS thin film solar cell  

OpenAIRE

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 ...

Ray, J. R.; Shah, N. M.; Desai, M. S.; Panchal, C. J.

2011-01-01

70

Characterization, modelling and optimization of industrial silicon thin film solar cells  

OpenAIRE

This PhD thesis has been mostly developed at T-Solar Global S.A., a factory of silicon thin film photovoltaic modules. The main objectives are divided in three lines of action. On the one hand, we have characterised the optical and electrical properties of silicon thin film layers and transparent conductive oxides, as well as 1cm2 research solar cells deposited in substrates of 2.6 m x 2.2 m size used in the T-Solar production line. To characterize the solar cells, we have mainly measured the...

Rodri?guez Gonza?lez, Jose? Antonio

2013-01-01

71

Analyzing periodic and random textured silicon thin film solar cells by Rigorous Coupled Wave Analysis  

Science.gov (United States)

A simple and fast method was developed to determine the quantum efficiency and short circuit current of thin-film silicon solar cells prepared on periodically or randomly textured surfaces. The optics was studied for microcrystalline thin-film silicon solar cells with integrated periodic and random surface textures. Rigorous Coupled Wave Analysis (RCWA) was used to investigate the behaviour of the solar cells. The analysis of the periodic and random textured substrates allows for deriving optimal surface textures. Furthermore, light trapping in periodic and randomly textured substrates will be compared.

Dewan, Rahul; Jovanov, Vladislav; Hamraz, Saeed; Knipp, Dietmar

2014-08-01

72

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

Czech Academy of Sciences Publication Activity Database

Ro?. 1, ?. 3 (2014), s. 135-137. ISSN 2336-2626 R&D Projects: GA Mk 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

Olejn?ek, Ji?; Hubi?ka, Zden?k; Kohout, Michal; Krov, Petra; Kment, t?pn; Brunclkov, Michaela; ?ada, Martin; Darveau, S.A.; Exstrom, C.L.

2014-01-01

73

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)

74

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.

75

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

Directory of Open Access Journals (Sweden)

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.

Morteza Eslamian

2014-01-01

76

Hydrogen passivation of polycrystalline Si thin film solar cells  

Energy Technology Data Exchange (ETDEWEB)

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.)

Gorka, Benjamin

2010-12-15

77

Light absorption enhancement in thin-film solar cells using whispering gallery modes in dielectric nanospheres  

Energy Technology Data Exchange (ETDEWEB)

A novel approach to increasing light absorption in thin-film solar cells is demonstrated. This new method involves redirecting the incident sunlight into the cell via coupling to the whispering gallery modes of dielectric spheres, which lie atop the cell. Such a scheme leads to a predicted current enhancement of >12% for a-Si.

Grandidier, Jonathan; Callahan, Dennis M; Munday, Jeremy N; Atwater, Harry A.

2011-01-01

78

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

OpenAIRE

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...

Morteza Eslamian

2014-01-01

79

Fabrication of nanocrystal ink based superstrate-type CuInS? thin film solar cells.  

Science.gov (United States)

A CuInS? (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, TiO? and CdS thin films were also prepared as a blocking layer and a buffer layer, respectively. We found that both a TiO? 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 TiO? and CdS films, respectively. PMID:22699212

Cho, Jin Woo; Park, Se Jin; Kim, Woong; Min, Byoung Koun

2012-07-01

80

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

81

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.)

82

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

OpenAIRE

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.

Zhang, Zhenhao

2012-01-01

83

?????????????????? Research Progress of Surface Plasmon Applied in Thin Film Solar Cells  

Directory of Open Access Journals (Sweden)

Full Text Available ????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????In order to transfer light to electricity efficiently, thin film solar cells with the structure of supporting surface plasmons in metal particles are designed. Due to the surface plasmons can guide and localize lights, the physical thickness of solar photovoltaic absorbing layer can be decreased as well as the absorption in photovoltaic devices can be improved. This technology plays an important role in fabricating low-cost and high-efficiency thin film solar cells. In this review, the latest progress of the application of plasmonics in solar cells is researched, the mechanism of the intersection of plasmonics and photovoltaics is expounded, and an outlook on the future of solar cells based on these principles is offered.

???

2011-10-01

84

Method of forming particulate materials for thin-film solar cells  

Science.gov (United States)

A method for preparing particulate materials useful in fabricating thin-film solar cells is disclosed. Particulate materials is prepared by the method include for example materials comprising copper and indium and/or gallium in the form of single-phase, mixed-metal oxide particulates; multi-phase, mixed-metal particulates comprising a metal oxide; and multinary metal particulates.

Eberspacher, Chris; Pauls, Karen Lea

2004-11-23

85

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

CERN Document Server

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.

Wang, DongLin; Su, Gang

2015-01-01

86

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

Directory of Open Access Journals (Sweden)

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.

Udai P. Singh

2010-01-01

87

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

88

Photovoltaic Technology: The Case for Thin-Film Solar Cells  

OpenAIRE

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...

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

2013-01-01

89

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

Energy Technology Data Exchange (ETDEWEB)

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 PVâ??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.

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

2012-06-11

90

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

Science.gov (United States)

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.

Wang, Qi; Iwaniczko, Eugene

2006-10-17

91

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

OpenAIRE

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 parameter...

Yue-Hui Hu; Yi-Chuan Chen; Hai-Jun Xu; Hao Gao; Wei-Hui Jiang; Fei Hu; Yan-Xiang Wang

2010-01-01

92

Local versus global absorption in thin-film solar cells with randomly textured surfaces  

Science.gov (United States)

Enhanced light absorption in amorphous silicon thin films deposited on randomly textured zinc-oxide surfaces is investigated by means of a rigorous diffraction theory taking into account measured surface profiles and near-field optical data. Global absorption enhancement is obtained in the calculations for particular modifications of the random texture. We furthermore spatially resolve local domains of the surface texture, which show the strongest contribution to the absorption. Criteria on how random surfaces should look like to enhance absorption in thin-film solar cells are derived.

Rockstuhl, C.; Fahr, S.; Lederer, F.; Bittkau, K.; Beckers, T.; Carius, R.

2008-08-01

93

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

OpenAIRE

Thin-film photovoltaic modules based on Cu-In-Ga-Se-S (CIS) and CdTe are already being produced with high-quality and solar conversion efficiencies of around 10%, with values up to 14% expected in the near future. The integrated interconnection of single cells into large-area modules of 0.6×1.2m2 enables low-cost mass production, so that thin-film modules will soon be able to compete with conventional silicon-wafer-based modules. This contribution provides an overview of the basic tec...

Dieter Bonnet; Michael Powalla

2007-01-01

94

Optical Layers for Thin-film Silicon Solar Cells  

OpenAIRE

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...

Cuony, Peter

2011-01-01

95

On the Scalar Scattering Theory for Thin-Film Solar Cells:  

OpenAIRE

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

Ja?ger, K.

2012-01-01

96

Effect of electrode separation on PECVD deposited nanocrystalline silicon thin film and solar cell properties  

Energy Technology Data Exchange (ETDEWEB)

Hydrogenated silicon thin films were prepared at different electrode separations and total gas flow rates. Nanocrystalline Si:H films with similar crystalline volume fraction deposited at lower electrode separation have lower microstructural factor. Quality of the absorber layer and solar cell performance improve as electrode separation and deposition power density simultaneously decrease. Maximum efficiency of 6.9% is obtained for solar cell with absorber layer deposited at an electrode separation of 1 cm. (author)

Chowdhury, Amartya; Mukhopadhyay, Sumita; Ray, Swati [Energy Research Unit, Indian Association for the Cultivation of Science, Kolkata-700 032 (India)

2010-09-15

97

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

OpenAIRE

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...

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

2013-01-01

98

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

Science.gov (United States)

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 m thick hybrid film. Efficiency decay is not observed in the inverted organic solar cell coated with this thin film after exposure to air for 3600 h in contrast, the efficiency of the unencapsulated counterpart degrades rapidly and fails after exposure to air for 120 h. The obtained results show that this organic-inorganic-hybrid thin film is promising for the encapsulation of organic solar cells.

Li, Yun-Shiuan; Tsai, Chih-Hung; Kao, Shao-Hsuan; Wu, I.-Wen; Chen, Jian-Zhang; Wu, Chih-I.; Lin, Ching-Fuh; Cheng, I.-Chun

2013-10-01

99

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

International Nuclear Information System (INIS)

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

100

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

Science.gov (United States)

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

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

2007-12-10

101

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

Directory of Open Access Journals (Sweden)

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 (55C 110C 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.

Peter Pikna

2014-10-01

102

Thin film solar cells using impure polycrystalline silicon  

OpenAIRE

Epitaxial solar cells have been studied with the view of using rather impure upgraded metallurgical grade (UMG)-Si as a substrate material. It is confirmed that transition elements have segregated during ingot growth and that impurities such as B, P, Al do not diffuse from substrate to epilayers, so that the latter have resistivity and electron diffusion length adequate to produce good solar cells. 10.3 % efficiency cells have been obtained. By spectral response measurements, interpreted thro...

Rodot, M.; Barbe, M.; Bouree, J. E.; Perraki, V.; Revel, G.; Kishore, R.; Pastol, J. L.; Mertens, R.; Caymax, M.; Eyckmans, M.

1987-01-01

103

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1992-04-01

104

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

105

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

Energy Technology Data Exchange (ETDEWEB)

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.

Fahr, Stephan

2011-11-22

106

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)

107

Light-trapping design of graphene transparent electrodes for efficient thin-film silicon solar cells.  

Science.gov (United States)

In this paper, the performance of solar cells with graphene transparent electrodes is compared with cells using conventional indium tin oxide (ITO) electrodes, and it is demonstrated the optical absorption of solar cells with bare graphene structure is worse than that of bare ITO structure because of the higher refractive index of graphene. To enhance the light trapping of graphene-based thin-film solar cells, a simple two-layer SiO(2)/SiC structure is proposed as antireflection coatings deposited on top of graphene transparent electrodes, and the thickness of each layer is optimized by differential evolution in order to enhance the optical absorption of a-Si:H thin-film solar cells to the greatest degree. The optimization results demonstrate the optimal SiO(2)/SiC/graphene structure can obtain 37.30% enhancement with respect to bare ITO structure, which has obviously exceeded the light-trapping enhancement of 34.15% for the optimal SiO(2)/SiC/ITO structure. Therefore, with the aid of the light-trapping structure, the graphene films are a very promising indium-free transparent electrode substitute for the conventional ITO electrode for use in cost-efficient thin-film silicon solar cells. PMID:22945173

Zhao, Yongxiang; Chen, Fei; Shen, Qiang; Zhang, Lianmeng

2012-09-01

108

Thin film solar cell inflatable ultraviolet rigidizable deployment hinge  

Science.gov (United States)

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.

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

109

Advanced Light Trapping of High-Efficiency Thin Film Silicon Solar Cells  

Science.gov (United States)

Kaneka has been proposing and developing the advanced super-light trapping (ASLT) structure for thin film silicon solar cells, which incorporates tailored light confinement structures in tandem thin film silicon solar cells to selectively enhance light trapping in top and bottom subcells. In this paper, we present the results of the development of intermediate reflectors with very low refractive index and the design and implementation of nanoimprinted substrates. We demonstrate that significant current gains are possible by reducing the refractive index of the interlayer beyond state-of-the-art values. In addition, we show that the transparent conductive oxide angular scattering properties correlate with the solar cell performance in the infrared part of the spectrum.

Meguro, Tomomi; Feltrin, Andrea; Suezaki, Takashi; Ichikawa, Mitsuru; Kuchiyama, Takashi; Adachi, Daisuke; Inaki, Osamu; Yoshikawa, Kunta; Koizumi, Gensuke; Uzu, Hisashi; Ueda, Hiroaki; Uto, Toshihiko; Fujimoto, Takahisa; Irie, Toru; Hayakawa, Hironori; Nakanishi, Naoaki; Yoshimi, Masashi; Yamamoto, Kenji

2012-10-01

110

Thin-Film Solar Cell Fabricated on a Flexible Metallic Substrate  

Science.gov (United States)

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).

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

2006-05-30

111

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

Science.gov (United States)

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.

Feng, Yudong; Zuo, Huaping; Wang, Zhimin

112

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

1997-11-01

113

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

CERN Document Server

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...

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

2013-01-01

114

Thin film solar cell configuration and fabrication method  

Science.gov (United States)

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.

Menezes, Shalini

2009-07-14

115

Development of thin-film polycrystalline silicon solar cells by a solid phase crystallization (SPC) method  

Energy Technology Data Exchange (ETDEWEB)

Polycrystalline silicon (poly-Si) thin films prepared by the solid phase crystallization (SPC) method were studied for photovoltaic materials. To improve the properties of the poly-Si thin film, a-Si films suited to the solid phase crystallization were investigated. It was found that TA/TO (peak height ratio of TA peak and TO peak) in Raman spectra of a-Si films had the good correlation with the average grain size, and a factor for the enlargement of grain size was an increase of distortion energy stored in a-Si films. The first adoption of a textured substrate was also performed, which had effects on the enlargement of grain size in poly-Si thin films by the SPC method. By applying the a-Si films with large TA/TO value on textured substrate, the n-type poly-Si thin-film with the grain size of 6 {micro}m was fabricated and this film showed the Hall mobility of 623 cm{sup 2}/Vs (electron density: 3.0 {times} 10{sup 15} cm{sup {minus}3}). A new heterojunction technology, which was called Artificially Constructed Junction (ACJ), was developed by depositions of thin a-Si films on single-crystalline silicon (c-Si). In a solar cell using this technology, a high conversion efficiency of 18.7% was achieved. This is the highest value ever reported for solar cells in which the junctions were fabricated at a low temperature of less than 200 C. In a thin-film poly-Si solar cell (thickness: 10 {micro}m) applying this technology, a conversion efficiency of 6.3% was also obtained and a collection efficiency of 51% was achieved at a wavelength of 900 nm. This high value attributes to the hole diffusion length of 11 {micro}m, which is longer than the poly-Si thickness.

Matsuyama, Takao; Baba, Toshiaki; Tanaka, Makoto; Isomura, Masao; Tsuda, Shinya; Nakano, Shoichi; Kuwano, Yukinori [Sanyo Electric Co., Ltd., Hirakata, Osaka (Japan). Functional Materials Research Center

1993-12-31

116

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

117

Advanced characterization techniques for thin film solar cells  

CERN Document Server

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

Rau, Uwe; Kirchartz, Thomas

2011-01-01

118

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

OpenAIRE

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...

Dreyer, Philippe; Morales-masis, Monica; Nicolay, Sylvain; Ballif, Christophe; Perruisseau-carrier, Julien

2013-01-01

119

Light absorption enhancement in thin-film solar cells using whispering gallery modes in dielectric nanospheres  

Energy Technology Data Exchange (ETDEWEB)

Freely propagating sunlight can be diffractively coupled and transformed into several guided whispering gallery modes within an array of wavelength scale dielectric spheres. Incident optical power is then transferred to the thin-film cell by leaky mode coupling into a thin solar cell absorber layer and significantly enhances its efficiency by increasing the fraction of incident light absorbed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Grandidier, Jonathan; Callahan, Dennis M.; Munday, Jeremy N.; Atwater, Harry A. [Thomas J. Watson Laboratories of Applied Physics, California Institute of Technology, Pasadena, CA 91125 (United States)

2011-03-11

120

Oxide and sulfide semiconductor thin films for solar cells and spintronic devices  

Science.gov (United States)

This dissertation will present the synthesis and characterization of the doped-zinc oxide (ZnO) thin films deposited by various techniques for their potential applications in spintronics devices and solar cells. The research work shows room temperature ferromagnetism in transition metal doped zinc oxide dilute magnetic semiconductors in highly crystalline nanostructured and polycrystalline forms. A spin field effect transistor working as a resistive switch was simulated based on the conductance modulation of the electron channel formed by magnetic impurity doped ZnO. Light scattering properties of nanostructured doped ZnO films has been simulated using Mie scattering theory in view of possible application in light harvesting in solar cells. Band gap bowing effect was achieved in sulfur-alloyed ZnO (zinc oxysulfide) films and a new bowing parameter and stress effect gave a better understanding of the sulfur alloyed effect in these polycrystalline thin films synthesized by chemical spray pyrolysis technique. A novel nanostructure was developed with sulfur-doping of ZnO in the ZnO core and zinc oxysulfide (ZnO1-xSx) shell form. For the first time the ZnO-ZnO1-xSx core-shell nanorods were applied to develop 3-dimenstional organic-inorganic hybrid solar cells. The performance of organic-inorganic hybrid solar cells based on ZnO-ZnO 1-xSx core-shell nanorods thin films was evaluated using the current-voltage characteristics. Further, the role of flux induced crystallization of Cu2ZnSnS4 (CZTS) thin films by chemical spray pyrolysis technique is explored. This dissertation also investigates the interface effects and heterojunction properties of cadmium sulfide/CZTS heterojunction solar cells.

Ramachandran Thankalekshmi, Ratheesh

121

IR-imaging and non-destructive loss analysis on thin film solar modules and cells  

Science.gov (United States)

CIGS thin film solar modules, despite their high efficiency, may contain three different kinds of macroscopic defects referred to as bulk defects, interface defects and interconnect defects. These occur due to the film's sensitivity to inhomogeneities during the manufacturing process and decreasing the electrical power output from a cell or module. In this study, we present infrared (IR) imaging and contactless loss analyses of defects contained in commercially manufactured thin film solar modules. We investigated different relations between the emitted IR-signal (using illuminated lock-in thermography ILIT) and the respective open circuit cell voltage (Voc) as well as the maximum power point (Pmpp). A simulation study, using the 2D finite element method (FEM), provides a deeper understanding as to the impact on electrical performance when defects are present on the cell or module.

Adams, Jens; Fecher, Frank W.; Hoga, Felix; Vetter, Andreas; Buerhop, Claudia; Brabec, Christoph J.

2014-10-01

122

Large area thin film cadmium telluride heterojunction solar cells  

Science.gov (United States)

Cadmium telluride films have been deposited by the direct combination of the elements on the surface of heated substrates in hydrogen. The resistivity of p-type films was controlled by (1) using a cadmium-deficient reaction mixture, and (2) adding a dopant to a nearly stoichiometric reaction mixture. Heterojunction solar cells were prepared from p-type cadmium telluride films by using cadmium oxide, cadmium sulfide, tin-doped indium oxide, and zinc oxide, deposited by ion-beam sputtering, spray pyrolysis, or vacuum evaporation, as the window material. Thus far, n-ITO/p-CdTe solar cells have the highest AMl efficiency, 8.1 percent for cells of 1 sq cm area. All heterojunction cells exhibit some degradation under continuous illumination, which may be minimized by passivation.

Chu, T. L.; Chu, S. S.; Firszt, F.; Nassem, H. A.; Stawski, R.

123

Quantum efficiency enhancement in selectively transparent silicon thin film solar cells by distributed Bragg reflectors.  

Science.gov (United States)

This work demonstrated a-Si:H thin-film solar cells with backside TiO(2) / SiO(2) distributed Bragg reflectors (DBRs) for applications involving building-integrated photovoltaics (BIPVs). Selectively transparent solar cells are formed by adjusting the positions of the DBR stop bands to allow the transmission of certain parts of light through the solar cells. Measurement and simulation results indicate that the transmission of blue light (430 ~500 nm) with the combination of three DBR mirrors has the highest increase in conversion efficiency. PMID:23326830

Kuo, M Y; Hsing, J Y; Chiu, T T; Li, C N; Kuo, W T; Lay, T S; Shih, M H

2012-11-01

124

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

Science.gov (United States)

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.

Woodyard, James R.; Landis, Geoffrey A.

1991-01-01

125

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

Energy Technology Data Exchange (ETDEWEB)

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.

Chang, S.T., E-mail: stchang@dragon.nchu.edu.tw; Hsieh, B.-F.

2011-12-30

126

Plasmonic absorption in textured silver back reflectors of thin film solar cells  

Science.gov (United States)

We study the influence of different textures and dielectric environments on the excitation of surface plasmon resonances on silver because textured metallic films often serve as back contacts of silicon thin film solar cells. For coupling between light and the surface plasmon excitation we use a periodic sinusoidal structure that enables us to sample the dispersion relation at well defined conditions with a simple spectral reflection measurement. We use three layer samples of amorphous silicon/ZnO/silver to mimic the behavior of the back contact in a thin film silicon solar cell; the measurements suggest that losses due to plasmon excitation can very well extend in the spectral region where optimum reflectance is desired. An appropriate thickness of ZnO is able to reduce absorption losses. Our findings on periodic structures are also found useful to explain the behavior of surface plasmon excitation on randomly textured ZnO/Ag reflector layers.

Haug, F.-J.; Sderstrm, T.; Cubero, O.; Terrazzoni-Daudrix, V.; Ballif, C.

2008-09-01

127

Highly crystallized sputtered silicon with textured morphology for thin-film solar cells  

Science.gov (United States)

A light-trapping structure with textured morphology for thin-film solar cell is demonstrated in this paper. It is fabricated through Al evaporation, and has a root-mean-roughness (Rms) of about 120 nm and lateral width of about 1 ?m for single bulge. A Mo layer is introduced to be a barrier layer. Subsequently sputtered amorphous silicon film is 100% crystallized by Cu induced crystallization. Reflectivity of samples with different silicon thickness is studied to reveal the light-trapping efficiency and the reflectivity as low as 10% is obtained with only 840 nm thick silicon film. This is a low-cost structure promising for future thin-film solar cells with high efficiency.

Hu, Qiang; Wang, Jian; Zhao, Yong; Li, Dejie

2011-03-01

128

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

Science.gov (United States)

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

Yin, J.; Zhu, H.; Wang, Y.; Wang, Z.; Gao, J.; Mai, Y.; Ma, Y.; Wan, M.; Huang, Y.

2012-10-01

129

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

Science.gov (United States)

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.

Junghanns, Marcus; Plentz, Jonathan; Andr, Gudrun; Gawlik, Annett; Hger, Ingmar; Falk, Fritz

2015-02-01

130

Microcrystalline silicon for thin-film solar cells  

OpenAIRE

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

Gordijn, Aad

2005-01-01

131

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

Czech Academy of Sciences Publication Activity Database

Ro?. 105, ?. 11 (2014), "111106-1"-"111106-4". ISSN 0003-6951 R&D Projects: GA ?R GA14-15357S; GA Mk(CZ) LM2011026; GA Mk 7E12029 Grant ostatn: 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

Ledinsk, Martin; Moulin, E.; Bugnon, G.; Ganzerov, Kristna; Vetushka, Aliaksi; Meillaud, F.; Fejfar, Antonn; Ballif, C.

2014-01-01

132

Peel-and-Stick: Fabricating Thin Film Solar Cell on Universal Substrates  

OpenAIRE

Fabrication of thin-film solar cells (TFSCs) on substrates other than Si and glass has been challenging because these nonconventional substrates are not suitable for the current TFSC fabrication processes due to poor surface flatness and low tolerance to high temperature and chemical processing. Here, we report a new peel-and-stick process that circumvents these fabrication challenges by peeling off the fully fabricated TFSCs from the original Si wafer and attaching TFSCs to vi...

Chi Hwan Lee; Dong Rip Kim; In Sun Cho; Nemeth William; Qi Wang; Xiaolin Zheng

2012-01-01

133

Chemical Etching of Zinc Oxide for Thin-Film Silicon Solar Cells  

OpenAIRE

Chemical etching is widely applied to texture the surface of sputter-deposited zinc oxide for light scattering in thin-film silicon solar cells. Based on experimental findings from the literature and our own results we propose a model that explains the etching behavior of ZnO depending on the structural material properties and etching agent. All grain boundaries are prone to be etched to a certain threshold, that is defined by the deposition conditions and etching solutio...

Hu?pkes, Ju?rgen; Owen, Jorj I.; Pust, Sascha E.; Bunte, Eerke

2011-01-01

134

Excitation of plasmon and guided-mode resonances in thin film silicon solar cells  

OpenAIRE

Thin film silicon solar cells are an attractive option for the production of sustainable energy but their low response at long wavelengths requires additional measures for absorption enhancement. The most successful concepts are based on light scattering interface textures whose understanding is greatly facilitated by considering a superposition of periodic textures that diffract the light into oblique angles, ideally beyond the critical angle of total internal reflection. Because the thickne...

Haug, Franz-josef

2011-01-01

135

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

Science.gov (United States)

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.

Klein, Andreas

2015-04-01

136

Plasmon supported defect absorption in amorphous silicon thin film solar cells and devices  

OpenAIRE

In this thesis the influence of metallic nanoparticles on the absorption of hydrogenated amorphous silicon (a-Si:H) thin film solar cell devices is investigated. Small metal nanostructures with lateral dimensions well below 100 nm accompany strong absorption and large electric field amplitudes in their vicinity. This is caused by the localized surface plasmon (LSP) resonances that are excited upon interaction of light with the nanostructures. By combining silver nanoparticles (Ag NPs) with am...

Lu?kermann, Florian

2013-01-01

137

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)

138

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.

139

Inline RF sputtered TAZO films for applications in hydrogenated amorphous silicon thin film solar cells  

Science.gov (United States)

In this paper, we aim to evaluate feasibility of replacing tin oxide (SnO2) films by in-line sputtered (titanium, aluminum)-doped zinc oxide (TAZO) as a front electrode of hydrogenated amorphous silicon (a-Si:H) thin film solar cells. The HCl wet-etching process and the device performances are investigated and optimized. The results show that the textured TAZO can have a lower sheet resistance of 7 ?/square and a higher haze of 22% compared to commercial Asahi-U SnO2 films. The a-Si:H solar cells with a TAZO front contact is found to have a low fill factor due to a poor TAZO/p-a-Si:H interface. However, the interface problem can be significantly improved by inserting a microcrystalline p-layer silicon thin-film. In addition, the reproducibility of the wet-etching process is investigated. The fluctuation in the haze of the etched TAZO films can be obviously reduced when a multi-step wet-etching process is used. Moreover, the light soaking test is performed on the TAZO films. Only slight degradation in film properties indicates high stability with respect to time. These results encourage potential adoption of cost-effective in-line sputtered TAZO films as an alternative for the front contact of a-Si:H thin film solar cells.

Lien, Shui-Yang; Hsu, Chia-Hsun; Chang, Chia-Hung; Wu, Hsin-Yu; Hsieh, In-Cha; Wang, Da-Yung

2014-02-01

140

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

Science.gov (United States)

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

Minami, Tadatsugu; Miyata, Toshihiro; Nomoto, Jun-ichi

2012-04-01

141

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

142

Microscopic characterizations of nanostructured silicon thin films for solar cells.  

Czech Academy of Sciences Publication Activity Database

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 Mk(CZ) LC06040; GA Mk(CZ) MEB061012; GA AV ?R KAN400100701; GA Mk LC510 Grant ostatn: 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

Fejfar, Antonn; Klapetek, P.; Zlmal, J.; Vetushka, Aliaksi; Ledinsk, Martin; Ko?ka, Jan

143

Si nanostructures thin films for 3rd generation of solar cells  

OpenAIRE

The combination of third generation solar cell concepts in second generation thin film materials has been identified as an efficient way to solve the global energy needs. The quantum confinement effects observed from Si nanostructures are promising towards integration in a third generation solar cell such as an 'All-Si tandem cell'. This thesis focuses on understanding the formation of Si quantum dots (i.e Si- nanoparticles) in two kinds of dielectric matrix: SiO2 and Silicon nitride, in mono...

Nalini, R. P.

2012-01-01

144

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

145

Microcrystalline silicon for thin-film solar cells  

Science.gov (United States)

Microcrystalline silicon (?c-Si:H) is a material that is promising for application in solar cells and that has interesting material properties. This thesis reports on the study of the plasma properties in the growth process, the optoelectronic material properties, and the device application of both doped and intrinsic ?c-Si:H. Microcrystalline silicon p- and n-type doped layers have been developed by layer-by-layer (LbL) deposition using very high frequency chemical vapor deposition (VHF PECVD) at high temperature. The LbL deposition consists of alternating amorphous silicon depositions and crystallization by hydrogen plasma treatments. Device quality ?c-Si:H p- and n-type doped thin layers have been developed in a temperature range from 250 to 400 C, whereas in standard continuous PECVD the addition of a dopant gas reduces the crystallinity. Etching, abstraction and hydrogen diffusion are analyzed and it is concluded that our observations support the nucleation model that is based on hydrogen diffusion in the growth zone. Test solar cells demonstrate the temperature stability and the resistance to high atomic hydrogen fluxes of these ?c-Si:H doped layers. Plasma conditions involving high pressures and high RF powers (high-pressure depletion (HPD) regime) for high-rate deposition by VHF PECVD of ?c-Si:H are explored by studying the optical emission spectra (OES) of the plasma. With an adapted electrode configuration with a shower head gas inlet and a small electrode distance, ?c-Si:H can be deposited at a high rate. Correlations between the material properties and the optical emission spectra of the plasma were found. Source gas depletion is found to be favorable to reduce the loss of atomic hydrogen to abstraction reactions in the gas phase at high pressures. The optoelectronic properties of microcrystalline silicon layers with different crystalline fractions have been studied with the aim to develop an intrinsic material for i-layer application in p-i-n solar cells. It is observed that ?c-Si:H deposited close to the transition to a-Si:H shows the best intrinsic behavior and the highest photo-to-dark conductivity ratio. At higher crystalline fractions, the dark conductivity increases while the dark conductivity activation energy decreases. The oxygen concentration in the layers is around 1019 cm-3. Microcrystalline silicon based p-i-n solar cells are deposited by VHF PECVD under HPD conditions using a shower head cathode. The i-layers made near the transition from amorphous to crystalline are optimized in solar cells. It was found that the performance is very sensitive to the TCO morphology. At an i-layer deposition rate of 0.45 nm/s an efficiency of 9.9% is obtained (Voc = 0.52 V, FF = 0.73) on texture-etched ZnO:Al; the performance is stable under light soaking. In spite of the presence of oxygen contamination a good infrared response is obtained. The i-layer deposition rate was increased up to 4.5 nm/s by increasing the RF power and the total gas flow such that the depletion condition remains similar. This resulted in an efficiency of 6.4% on texture-etched ZnO:Al. It was observed that the performance of cells deposited at these high rates improves upon light soaking.

Gordijn, Aad

2005-04-01

146

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

147

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

148

Analysis of the p+/p window layer of thin film solar cells by simulation  

International Nuclear Information System (INIS)

The application of a p+/p configuration in the window layer of hydrogenated amorphous silicon thin film solar cells is simulated and analyzed utilizing an AMPS-1D program. The differences between p+?pin configuration solar cells and pin configuration solar cells are pointed out. The effects of dopant concentration, thickness of p+-layer, contact barrier height and defect density on solar cells are analyzed. Our results indicate that solar cells with a p+?pin configuration have a better performance. The open circuit voltage and short circuit current were improved by increasing the dopant concentration of the p+ layer and lowering the front contact barrier height. The defect density at the p/i interface which exceeds two orders of magnitude in the intrinsic layer will deteriorate the cell property. (semiconductor materials)

149

Broad-band anti-reflection coupler for a : Si thin-film solar cell  

International Nuclear Information System (INIS)

This work numerically demonstrates a new anti-reflection coupler (ARC) with high coupling efficiency in a Si substrate solar cell. The ARC in which the grating is integrated on a glass encapsulation and a three-layer impedance match layer is proposed. A coupling efficiency of 90% is obtained at wavelengths between 350 and 1200 nm in the TE and TM modes when the incident angle is less than 300. In comparison with a 1?m absorber layer, the integrated absorption of an a-Si thin-film solar cell without a new ARC is doubled, at long wavelengths (750 nm ? ? ? 1200 nm), as calculated by FDTD method

150

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

OpenAIRE

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 ...

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

2014-01-01

151

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

Directory of Open Access Journals (Sweden)

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.

Gabriel Onno

2014-02-01

152

Commercial white paint as back surface reflector for thin-film solar cells  

Energy Technology Data Exchange (ETDEWEB)

In this work, commercially available white paint is applied as a pigmented diffuse reflector (PDR) on the rear surface of thin-film crystalline silicon (c-Si) solar cells with a silicon thickness in the 1-2 {mu}m range. We show that white paint increases the short-circuit current density of the solar cells enormously, with a boost of 41% observed for very thin planar solar cells illuminated with the global AM1.5 solar spectrum. We also show that white paint is a better back surface reflector (BSR) than aluminium, air, a transparent conductive oxide (TCO)/aluminium stack, and even a detached aluminium mirror. While previous studies have investigated the influence of PDRs on silicon solar cells with thicknesses of over 27 {mu}m, this work closes the gap that has existed for much thinner cells. (author)

Berger, Olaf; Inns, Daniel; Aberle, Armin G. [Photovoltaics Centre of Excellence, The University of New South Wales, UNSW, Sydney, NSW 2052 (Australia)

2007-08-15

153

Characteristics of p-type nanocrystalline silicon thin films developed for window layer of solar cells  

Energy Technology Data Exchange (ETDEWEB)

Different rf-power and chamber pressures have been used to deposit boron doped hydrogenated silicon films by the PECVD method. The optoelectronic and structural properties of the silicon films have been investigated. With the increase of power and pressure the crystallinity of the films increases while the absorption decreases. As a very thin p-layer is needed in p-i-n thin film solar cells the variation of properties with film thickness has been studied. The fraction of crystallinity and thus dark conductivity vary also with the thickness of the film. Conductivity as high as 2.46 S cm{sup -1} has been achieved for 400 A thin film while for 3000 A thick film it is 21 S cm{sup -1}. Characterization of these films by XRD, Raman Spectroscopy, TEM and SEM indicate that the grain size, crystalline volume fraction as well as the surface morphology of p-layers depend on the deposition conditions as well as on the thickness of the film. Optical band gap varies from 2.19 eV to 2.63 eV. The thin p-type crystalline silicon film with high conductivity and wide band gap prepared under high power and pressure is suitable for application as window layer for Silicon thin film solar cells. (author)

Adhikary, Koel; Ray, Swati [Indian Association for the Cultivation of Science, Energy Research Unit, Jadavpur, Kolkata 700032, West Bengal (India)

2007-07-01

154

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

Science.gov (United States)

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.

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

155

Electron beam evaporation deposition of cadmium sulphide and cadmium telluride thin films: Solar cell applications  

International Nuclear Information System (INIS)

Cadmium sulphide (CdS) and cadmium telluride (CdTe) thin films are deposited by electron beam evaporation. Atomic force microscopy (AFM) reveals that the root mean square (RMS) roughness values of the CdS films increase as substrate temperature increases. The optical band gap values of CdS films increase slightly with the increase in the substrate temperature, in a range of 2.422.48 eV. The result of Hall effect measurement suggests that the carrier concentration decreases as the substrate temperature increases, making the resistivity of the CdS films increase. CdTe films annealed at 300C show that their lowest transmittances are due to their largest packing densities. The electrical characteristics of CdS/CdTe thin film solar cells are investigated in dark conditions and under illumination. Typical rectifying and photovoltaic properties are obtained. (interdisciplinary physics and related areas of science and technology)

156

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

Science.gov (United States)

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 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 2- xSe 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 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.

Ambade, Swapnil B.; Mane, R. S.; Kale, S. S.; Sonawane, S. H.; Shaikh, Arif V.; Han, Sung-Hwan

2006-12-01

157

Electron beam evaporation deposition of cadmium sulphide and cadmium telluride thin films: Solar cell applications  

Science.gov (United States)

Cadmium sulphide (CdS) and cadmium telluride (CdTe) thin films are deposited by electron beam evaporation. Atomic force microscopy (AFM) reveals that the root mean square (RMS) roughness values of the CdS films increase as substrate temperature increases. The optical band gap values of CdS films increase slightly with the increase in the substrate temperature, in a range of 2.42-2.48 eV. The result of Hall effect measurement suggests that the carrier concentration decreases as the substrate temperature increases, making the resistivity of the CdS films increase. CdTe films annealed at 300C show that their lowest transmittances are due to their largest packing densities. The electrical characteristics of CdS/CdTe thin film solar cells are investigated in dark conditions and under illumination. Typical rectifying and photovoltaic properties are obtained.

Fang, Li; Chen, Jing; Xu, Ling; Su, Wei-Ning; Yu, Yao; Xu, Jun; Ma, Zhong-Yuan

2013-09-01

158

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

159

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)

160

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

161

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

Directory of Open Access Journals (Sweden)

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

Dieter Bonnet

2007-09-01

162

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

Science.gov (United States)

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.

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

2002-01-01

163

Rigorous optical simulation of rough interface light trapping structures in thin film silicon solar cells  

Energy Technology Data Exchange (ETDEWEB)

Thin film silicon solar cells suffer from the disadvantage of a low absorption coefficient of silicon in important spectral regions. In the case of a flat multilayer cell layout a considerable part of the incident light is reflected back out of the cell due to the low absorber thickness. It is therefore desirable to introduce scattering elements that prolong the average photon path length inside the solar cell's absorber. Rough interfaces between the layers of a solar cell have proven to provide efficient and industrially producible light trapping structures. As the scattering structures and the layer thicknesses are in the order of only a few ten wavelengths coherence effects have to be taken into account in the simulation and optimization of such structures. We employ the finite element method for rigorous simulation of Maxwell's equations on 2D and 3D geometries to investigate light trapping effects produced by rough interfaces in thin film silicon solar cells. To approximate an extended rough surface we examine the influence of boundary conditions and a finite computational domain size on the absorption. We apply Monte Carlo sampling over sets of surface representations to obtain averaged measurement quantities. Simulations of 2- and 3-dimensional rough surface geometries are compared.

Lockau, Daniel [Helmholtz-Zentrum Berlin, Berlin (Germany); Zuse-Institut Berlin, Berlin (Germany); Burger, Sven; Zschiedrich, Lin; Schmidt, Frank [Zuse-Institut Berlin, Berlin (Germany); JCMwave GmbH, Berlin (Germany); Rech, Bernd [Helmholtz-Zentrum Berlin, Berlin (Germany)

2010-07-01

164

Electrodeposition of antimony selenide thin films and application in semiconductor sensitized solar cells.  

Science.gov (United States)

Sb2Se3 thin films are proposed as an alternative light harvester for semiconductor sensitized solar cells. An innovative electrodeposition route, based on aqueous alkaline electrolytes, is presented to obtain amorphous Sb2Se3. The amorphous to crystalline phase transition takes place during a soft thermal annealing in Ar atmosphere. The potential of the Sb2Se3 electrodeposited thin films in semiconductor sensitized solar cells is evaluated by preparing TiO2/Sb2Se3/CuSCN planar heterojunction solar cells. The resulting devices generate electricity from the visible and NIR photons, exhibiting the external quantum efficiency onset close to 1050 nm. Although planar architecture is not optimized in terms of charge carrier collection, photocurrent as high as 18 mA/cm(2), under simulated (AM1.5G) solar light, is achieved. Furthermore, the effect of the Sb2Se3 thickness and microstructural properties on the photocurrent is analyzed, suggesting the hole transport is the main limiting mechanism. The present findings provide significant insights to design efficient semiconductor sensitized solar cells based on advanced architectures (e.g., nanostructured and tandem), opening wide possibilities for progresses in this emerging photovoltaics technology. PMID:24437500

Ngo, T Tuyen; Chavhan, Sudam; Kosta, Ivet; Miguel, Oscar; Grande, Hans-Jurgen; Tena-Zaera, Ramn

2014-02-26

165

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

Science.gov (United States)

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

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

2014-12-01

166

Mode coupling by plasmonic surface scatterers in thin-film silicon solar cells  

Science.gov (United States)

We demonstrate effective mode coupling by light scattering from periodic Ag nanoparticle arrays printed onto a completed thin-film a-Si:H solar cell. Current-voltage measurements show a photocurrent enhancement of 10% compared to a flat reference cell with a standard antireflection coating. External quantum efficiency measurements for the nanopatterned cells show clear infrared photocurrent enhancement peaks, corresponding to coupling to discrete waveguide modes in the a-Si:H layer. The data are in good agreement with three-dimensional finite element simulations, which are used to further optimize the design. We show that broadband photocurrent enhancement can be obtained over the 450-750 nm spectral range.

van Lare, M.; Lenzmann, F.; Verschuuren, M. A.; Polman, A.

2012-11-01

167

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-09-15

168

Growth, Etching, and Stability of Sputtered ZnO:AI for Thin-Film Silicon Solar Cells  

OpenAIRE

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 ...

Owen, Jorj Ian

2011-01-01

169

Thin Film intermediate band chalcopyrite solar cells: Theoretical Analysis of device performance and prospects for their realisation  

OpenAIRE

The feasibility of implementing the intermediate-band (IB) concept into a relevant thin-film technology has been assessed. Compounds belonging to the group of I-III-VI2 chalcopyrites, currently used as absorbers in the leading thin-film technology, appear as promising candidates for the realization of IB-devices. In this paper we first analyze the expected performance of such a thin-film intermediate band solar cell (TF-IBSC) by considering different levels of idealization. In the second...

Fuertes Marro?n, David; Marti? Vega, Antonio; Tablero Crespo, Ce?sar; Antoli?n Ferna?ndez, Elisa; Ca?novas Di?az, Enrique; Garci?a-linares Fontes, Pablo; Luque Lo?pez, Antonio

2009-01-01

170

Progress towards high efficiency polycrystalline thin-film GaAs AMOS solar cells  

Science.gov (United States)

Results of Ge film recrystallization using focused laser beams and GaAs film growth on such layers in the making of high efficiency thin-film AMOS solar cells are discussed. Since a conversion efficiency of 14% was obtained for an AMOS cell fabricated on sliced bulk polycrystalline GaAs, high efficiency cells are being developed by chemically vapor-depositing GaAs films on previously recrystallized evaporated Ge films to minimize the grain boundary (GB) effects. Schottky barrier solar cells made on sliced polycrystalline GaAs wafers were studied to investigate the effects of grain boundaries on cell properties and the potential efficiency of GaAs thin-film cells. Ge film recrystallization and the chemical vapor deposition (CVD) of the 2 to 3 micron thick GaAs films are described. AMOS solar cells with 100 Angstrom thick Ag metallization were made on CVD GaAs/recrystallized Ge/W substrates with an energy conversion efficiency of 8%.

Yeh, Y. C. M.; Ernest, F. P.; Stirn, R. J.

1978-01-01

171

Fabrication of solution processed 3D nanostructured CuInGaS? thin film solar cells.  

Science.gov (United States)

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

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

2014-03-28

172

Comparison between periodic and stochastic parabolic light trapping structures for thin-film microcrystalline Silicon solar cells  

OpenAIRE

Light trapping is of very high importance for silicon photovoltaics (PV) and especially for thin-film silicon solar cells. In this paper we investigate and compare theoretically the light trapping properties of periodic and stochastic structures having similar geometrical features. The theoretical investigations are based on the actual surface geometry of a scattering structure, characterized by an atomic force microscope. This structure is used for light trapping in thin-film microcrystallin...

Peters, M.; Battaglia, C.; Forberich, K.; Blaesi, B.; Sahraei, N.; Aberle, A. G.

2012-01-01

173

Analysis of thin-film silicon solar cells with white paint back reflectors  

Energy Technology Data Exchange (ETDEWEB)

In this work, we investigate the concept of transparent conductive oxide (TCO)/white paint (WP) back reflectors as an alternative to the conventional textured metal-based reflectors in thin-film silicon solar cells. The optical characterisation results show that WP back reflectors exhibit good reflectivity and excellent light scattering properties which can lead to enhanced light confinement within the thin absorber layers of the cell. To confirm this, ZnO:Al/WP reflectors with WP films of different pigment volume concentration and thickness are tested in thin-film amorphous silicon solar cells. The external quantum efficiency measurements indicate that by employing ZnO:Al/WP reflectors, good solar cell performance can be achieved, which is comparable to the performance of the cell with the conventional TCO/Ag reflector. Finally, optical simulations are employed to study the potential for further improvements in cell performance as a result of the optimisation of TCO/WP reflectors. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Lipovsek, Benjamin; Krc, Janez; Topic, Marko [University of Ljubljana, Faculty of Electrical Engineering, Trzaska 25, 1000 Ljubljana (Slovenia); Isabella, Olindo; Zeman, Miro [Delft University of Technology - Electrical Energy Conversion Unit/DIMES, P.O. Box 5053, 2600 GB Delft (Netherlands)

2010-04-15

174

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

Science.gov (United States)

Crystalline silicon solar cells use high cost processing techniques as well as thick materials that are 200m 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 0.1-3m 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.

Pattnaik, Sambit

175

A new technique for large-area thin film CdS/CdTe solar cells  

Energy Technology Data Exchange (ETDEWEB)

The atmospheric pressure CSS method has been developed as a reproducible and efficient process. Thin film CdTe grown under atmospheric pressure has a rough surface morphology. The density of carbon black powder in the graphite carbon paste for screen printing is a key factor in reducing the series resistance of the device with rough surface CdTe. Using graphite carbon paste with 7 wt% carbon black powder has resulted in cells with a relatively low back contact resistance. A highly efficient large-area CdS/CdTe solar cell (11.0%, 5327 cm{sup 2}) sub-module has been fabricated using the new technique. (Author)

Aramoto, T.; Adurodija, F.; Nishiyama, Y.; Arita, T.; Hanafusa, A.; Omura, K.; Morita, A. [Matsushita Battery Industrial Co. Ltd., PV R and D Center, Osaka (Japan)

2003-01-01

176

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.

177

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.

178

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)

179

Spectroscopic aspects of front transparent conductive films for a-Si thin film solar cells  

Science.gov (United States)

This work demonstrates a method to optimize the indium tin oxide (ITO) thin films as front transparent electrode to maximize the efficiency of substrate type amorphous silicon (a-Si) based thin film solar cells. It shows that the total light intensity absorbed by the a-Si layer can be predicted by combining a multilayer optical simulation with the nonuniform solar spectrum and the spectroscopic response of the absorption coefficient of the a-Si film. Consequently, an optimized ITO film can be identified. The photovoltaic performances of experimentally obtained a-Si single junction solar cells confirm the simulation results, indicating an ITO film about 56 nm thick leads to the highest efficiency. Furthermore, it is shown that the ITO films should be deposited at relatively low temperature around 132 C to avoid damage to the a-Si top p-layer and p-i-n junction. It is found that introducing a small fraction, 0.61% flow ratio, of O2 in the sputtering Ar gas reduces the sheet resistivity of the ITO film and improves its transmittance, leading to higher efficiency a-Si solar cells.

Fan, Qi Hua; Chen, Changyong; Liao, Xianbo; Xiang, Xianbi; Cao, Xinmin; Ingler, William; Adiga, Nirupama; Deng, Xunming

2010-02-01

180

Defect annealing processes for polycrystalline silicon thin-film solar cells  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-05-15

181

Polycrystalline ZnO: B grown by LPCVD as TCO for thin film silicon solar cells  

International Nuclear Information System (INIS)

Conductive zinc oxide (ZnO) grown by low pressure chemical vapor deposition (LPCVD) technique possesses a rough surface that induces an efficient light scattering in thin film silicon (TF Si) solar cells, which makes this TCO an ideal candidate for contacting such devices. IMT-EPFL has developed an in-house LPCVD process for the deposition of nanotextured boron doped ZnO films used as rough TCO for TF Si solar cells. This paper is a general review and synthesis of the study of the electrical, optical and structural properties of the ZnO:B that has been performed at IMT-EPFL. The influence of the free carrier absorption and the grain size on the electrical and optical properties of LPCVD ZnO:B is discussed. Transport mechanisms at grain boundaries are studied. It is seen that high doping of the ZnO grains facilitates the tunnelling of the electrons through potential barriers that are located at the grain boundaries. Therefore, even if these potential barriers increase after an exposition of the film to a humid atmosphere, the heavily doped LPCVD ZnO:B layers show a remarkable stable conductivity. However, the introduction of diborane in the CVD reaction induces also a degradation of the intra-grain mobility and increases over-proportionally the optical absorption of the ZnO:B films. Hence, the necessity to finely tune the doping level of LPCVD ZnO:B films is highlighted. Finally, the next challenges to push further the optimization of LPCVD ZnO:B films for thin film sition of LPCVD ZnO:B films for thin film silicon solar cells are discussed, as well as some remarkable record cell results achieved with LPCVD ZnO:B as front electrode.

182

Light trapping with plasmonic back contacts in thin-film silicon solar cells  

Energy Technology Data Exchange (ETDEWEB)

Trapping light in silicon solar cells is essential as it allows an increase in the absorption of incident sunlight in optically thin silicon absorber layers. This way, the costs of the solar cells can be reduced by lowering the material consumption and decreasing the physical constraints on the material quality. In this work, plasmonic light trapping with Ag back contacts in thin-film silicon solar cells is studied. Solar cell prototypes with plasmonic back contacts are presented along with optical simulations of these devices and general design considerations of plasmonic back contacts. Based on three-dimensional electromagnetic simulations, the conceptual design of plasmonic nanostructures on Ag back contacts in thin-film silicon solar cells is studied in this work. Optimizations of the nanostructures regarding their ability to scatter incident light at low optical losses into large angles in the silicon absorber layers of the thin-film silicon solar cells are presented. Geometrical parameters as well as the embedding dielectric layer stack of the nanostructures on Ag layers are varied. Periodic as well as isolated hemispherical Ag nanostructures of dimensions above 200 nm are found to scatter incident light at high efficiencies and low optical losses. Hence, these nanostructures are of interest for light trapping in solar cells. In contrast, small Ag nanostructures of dimension below 100 nm are found to induce optical losses. At the surface of randomly textured Ag back contacts small Ag nanostructures exist which induce optical losses. In this work, the relevance of these localized plasmon induced optical losses as well as optical losses caused by propagating plasmons are investigated with regard to the reflectance of the textured back contacts. In state-of-the-art solar cells, the plasmon-induced optical losses are shifted out of the relevant wavelength range by incorporating a ZnO:Al interlayer of low refractive index at the back contact. The additional but small potential for increasing the reflection at the back contact with dielectric interlayers of even lower refractive index, such as SiO{sub 2} and air, is demonstrated. The light-trapping effect of two types of plasmonic back contacts, which make use of large and efficiently scattering Ag nanostructures, is studied in thin-film silicon solar cell prototypes. The first type of plasmonic back contact applies 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. Measured reflectance spectra of the Ag back contacts with non-ordered nanostructures are correlated with reflectance spectra derived from three-dimensional electromagnetic simulations of isolated nanostructures on Ag back contacts. A microcrystalline silicon solar cell fabricated on one type of plasmonic Ag back contact with non-ordered Ag nanostructures shows a significantly enhanced plasmonic light trapping when compared with a flat solar cell. The second type of plasmonic back contact applies periodic arrangements of plasmonic Ag nanostructures in a square lattice at the surface of the Ag back contact. It is called a plasmonic reflection grating back contact. A particular advantage of this device is the control of the scattering angles via the diffraction orders of the grating while taking advantage of the efficient plasmon-induced light scattering at the Ag nanostructures. The plasmonic reflection grating back contacts are prepared with a nanoimprint process. The prototype microcrystalline silicon solar cells exhibit a very good light-trapping effect. Even in comparison with solar cells with a state-of-the-art random texture for light trapping, an enhanced light-trapping effect is demonstrated for a solar sell with a plasmonic reflection grating of optimized period. Based on electromagnetic simulations, the light-trapping effect is explained from the intuitive perspective of geometrical optics as well as from the perspective of leaky waveguides.

Paetzold, Ulrich Wilhelm

2013-02-08

183

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

Science.gov (United States)

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.

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

2012-06-01

184

Back contact buffer layer for thin-film solar cells  

Science.gov (United States)

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.

Compaan, Alvin D.; Plotnikov, Victor V.

2014-09-09

185

Positive ion irradiation of CdS/Cu2S thin film solar cells  

International Nuclear Information System (INIS)

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

186

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

OpenAIRE

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...

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

2010-01-01

187

Properties of the new absorber antimony tin sulphide thin films for solar cell applications  

International Nuclear Information System (INIS)

The new absorber layer antimony tin sulphide thin film was deposited by physical vapor deposition (PVD) using two source simultaneous deposition techniques for solar cell applications. The structural properties were measured by using XRD techniques. The quantum efficiency was measured by photoconductivity spectrometer shows the photo-activeness of the material. The thickness, band gap, refractive index and transmittance were calculated by using ellipsometry techniques. The transmittance of the material was above the visible range which decreases with the increase in wavelength. The material has n-type conductivity measured with hot probe technique. (author)

188

Self-organized broadband light trapping in thin film amorphous silicon solar cells.  

Science.gov (United States)

Nanostructured glass substrates endowed with high aspect ratio one-dimensional corrugations are prepared by defocused ion beam erosion through a self-organized gold (Au) stencil mask. The shielding action of the stencil mask is amplified by co-deposition of gold atoms during ion bombardment. The resulting glass nanostructures enable broadband anti-reflection functionality and at the same time ensure a high efficiency for diffuse light scattering (Haze). It is demonstrated that the patterned glass substrates exhibit a better photon harvesting than the flat glass substrate in p-i-n type thin film a-Si:H solar cells. PMID:23633473

Martella, C; Chiappe, D; Delli Veneri, P; Mercaldo, L V; Usatii, I; Buatier de Mongeot, F

2013-06-01

189

Resonant and nonresonant plasmonic nanoparticle enhancement for thin-film silicon solar cells  

Energy Technology Data Exchange (ETDEWEB)

This paper investigates the influence of resonant and nonresonant plasmonic nanostructures, such as arrays of silver and aluminum nanoparticles in the forward scattering configuration, on the optical absorption in a thin-film amorphous silicon solar cell. It is demonstrated that nonresonant coupling of the incident sunlight with aluminum nanoparticles results in higher optical absorption in the photoactive region than resonant coupling with silver nanoparticle arrays. In addition, aluminum nanoparticles are shown to maintain a net positive enhancement of the optical absorption in amorphous silicon, as compared to a negative effect by silver nanoparticles, when the nanoparticles are oxidized.

Akimov, Yu A; Koh, W S, E-mail: kohws@ihpc.a-star.edu.sg [Advanced Photonics and Plasmonics Team, Computational Electronics and Photonics Programme, Institute of High Performance Computing, 1 Fusionopolis Way, 16-16 Connexis, 138632 (Singapore)

2010-06-11

190

Resonant and nonresonant plasmonic nanoparticle enhancement for thin-film silicon solar cells  

International Nuclear Information System (INIS)

This paper investigates the influence of resonant and nonresonant plasmonic nanostructures, such as arrays of silver and aluminum nanoparticles in the forward scattering configuration, on the optical absorption in a thin-film amorphous silicon solar cell. It is demonstrated that nonresonant coupling of the incident sunlight with aluminum nanoparticles results in higher optical absorption in the photoactive region than resonant coupling with silver nanoparticle arrays. In addition, aluminum nanoparticles are shown to maintain a net positive enhancement of the optical absorption in amorphous silicon, as compared to a negative effect by silver nanoparticles, when the nanoparticles are oxidized.

191

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

Science.gov (United States)

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/Vs, and the decreased resistivity to 1.42 10-3 ?cm are successfully obtained to be advantageous for a window layer in solar cells.

Kim, Nam-Hoon; Myung Kuk, Do; Lee, Woo-Sun

2012-12-01

192

Cu2SnS3 as a potential absorber for thin film solar cells  

Science.gov (United States)

The properties of pure Cu2SnS3 thin films synthesized by direct liquid coating method have been studied for application in TFSCs. The films have band gap of 1.12 eV and an absorption coefficient of 105 cm-1. They are p-type with electrical conductivity of 0.5 S/cm and show photoconductivity. TFSCs made of these p-CTS films and n-CdS have been analyzed. The maximum efficiency of CTS solar cells is 33% with VOC and ISC of 0.75 V and 40 mA/cm.

Tiwari, Devendra; Chaudhuri, T. K.; Shripathi, T.; Deshpande, U.

2012-06-01

193

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/Vs, and the decreased resistivity to 1.42 10?3 ?cm are successfully obtained to be advantageous for a window layer in solar cells

194

Mixed phase silicon oxide layers for thin-film silicon solar cells  

OpenAIRE

Lower absorption, lower refractive index and tunable resistance are three advantages of doped silicon oxide containing nanocrystalline silicon grains (nc-SiOx) compared to doped microcrystalline silicon, for the use as p- and n-type layers in thin-film silicon solar cells. In this study we show how optical, electrical and microstructural properties of nc-SiOx layers depend on precursor gas ratios and we propose a growth model to explain the phase separation in such films into Si-rich and O-ri...

Cuony, Peter; T L Alexander, Duncan; Lo?fgren, Nils Linus; Krumrey, Michael; Marending, Michael; Despeisse, Matthieu; Ballif, Christophe

2011-01-01

195

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

Science.gov (United States)

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 1eV 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

Klein, Andreas

2015-04-10

196

Self-organized broadband light trapping in thin film amorphous silicon solar cells  

Science.gov (United States)

Nanostructured glass substrates endowed with high aspect ratio one-dimensional corrugations are prepared by defocused ion beam erosion through a self-organized gold (Au) stencil mask. The shielding action of the stencil mask is amplified by co-deposition of gold atoms during ion bombardment. The resulting glass nanostructures enable broadband anti-reflection functionality and at the same time ensure a high efficiency for diffuse light scattering (Haze). It is demonstrated that the patterned glass substrates exhibit a better photon harvesting than the flat glass substrate in p-i-n type thin film a-Si:H solar cells.

Martella, C.; Chiappe, D.; Delli Veneri, P.; Mercaldo, L. V.; Usatii, I.; Buatier de Mongeot, F.

2013-06-01

197

Self-organized broadband light trapping in thin film amorphous silicon solar cells  

International Nuclear Information System (INIS)

Nanostructured glass substrates endowed with high aspect ratio one-dimensional corrugations are prepared by defocused ion beam erosion through a self-organized gold (Au) stencil mask. The shielding action of the stencil mask is amplified by co-deposition of gold atoms during ion bombardment. The resulting glass nanostructures enable broadband anti-reflection functionality and at the same time ensure a high efficiency for diffuse light scattering (Haze). It is demonstrated that the patterned glass substrates exhibit a better photon harvesting than the flat glass substrate in pin type thin film a-Si:H solar cells. (paper)

198

Localized plasmonic losses at metal back contacts of thin-film silicon solar cells  

Science.gov (United States)

Investigations of optical losses induced by localized plasmons in protrusions on silver back contacts of thin-film silicon solar cells are presented. The interaction of electromagnetic waves with nanoprotrusions on flat silver layers is simulated with a three-dimensional numerical solver of Maxwell's equations. Spatial absorption profiles and spatial electric field profiles as well as the absorption inside the protrusions are calculated. The results presented here show that the absorption of irradiated light at nanorough silver layers can be strongly enhanced by localized plasmonic resonances in Ag nanoprotrusions. Especially, localized plasmons in protrusions with a radius below 60 nm induce strong absorption, which can be several times the energy irradiated on the protrusion's cross section. The localized plasmonic resonances in single protrusions on Ag layers are observed to shift to longer wavelengths with increasing refractive index of the surrounding material. At wavelengths above 500 nm localized plasmonic resonances will increase the absorption of nanorough ?c-Si:H/Ag interfaces. The localized plasmon induced absorption at nanorough ZnO/Ag interfaces lies at shorter wavelengths due to the lower refractive index of ZnO. For wavelengths above 500 nm, a high reflectivity of the silver back contacts is essential for the light-trapping of thin-film silicon solar cells. Localized-plasmon induced losses at silver back contacts can explain the experimentally observed increase of the solar cell performance when applying a ZnO/Ag back contact in comparison to a ?c-Si:H/Ag back contact.

Paetzold, U. W.; Hallermann, F.; Pieters, B. E.; Rau, U.; Carius, R.; von Plessen, G.

2010-05-01

199

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

Science.gov (United States)

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

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

2014-06-30

200

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

International Nuclear Information System (INIS)

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

201

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-03-15

202

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

Science.gov (United States)

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

Fang, Fang

2011-12-01

203

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

Science.gov (United States)

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.

Gmez, D.; Menndez, A.; Snchez, P.; Martnez, A.; Andrs, L. J.; Menndez, M. F.; Campos, N.; Garca, A.; Snchez, B.

2011-09-01

204

Fabrication, characterization and interface study of CdS/CdTe thin film solar cells  

International Nuclear Information System (INIS)

Thin films of CdTe and ZnTe are optically and electrically characterized during the course of this research work. Various samples are of CdS/CdTe solar cells are prepared on glass and copper substrate. These samples are then subjected to electrical measurements. For the interface study of CdS/CdTe junction, thin films of CdS CdTe are fabricated on single crystal Si substrate to form CdTe/CdS/Si and ZnTe/CdTe/CdS/Si samples. These samples are analyzed for interface study by using Auger Electron Spectroscopy. Finally, the results obtained by interface study are compared with that for electrical measurements obtained earlier, and it is found that the open circuit voltage for the solar cells is close to the optimum value but the short circuit current values for the same cells are away from the optimum value. The is because of the formation of a resistive layer in the vicinity of the junction of the cell due to unwanted mixing taking place in these samples especially in the CdTe/CdS junction. (author)

205

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

Energy Technology Data Exchange (ETDEWEB)

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.)

Wagner, H.

2001-07-01

206

Light trapping in thin film solar cells using photonic engineering device concepts  

Science.gov (United States)

In this era of uncertainty concerning future energy solutions, strong reservations have arisen over the continued use and pursuit of fossil fuels and other conventional sources of energy. Moreover, there is currently a strong and global push for the implementation of stringent measures, in order to reduce the amount of green house gases emitted by every nation. As a consequence, there has emerged a sudden and frantic rush for new renewable energy solutions. In this world of renewable energy technologies is where we find photovoltaic (PV) technology today. However, as is, there are still many issues that need to be addressed before solar energy technologies become economically viable and available to all people, in every part of the world. This renewed interest in the development of solar electricity, has led to the advancement of new avenues that address the issues of cost and efficiency associated with PV. To this end, one of the prominent approaches being explored is thin film solar cell (TFSC) technology, which offers prospects of lower material costs and enables larger units of manufacture than conventional wafer based technology. However, TFSC technologies suffer from one major problem; they have lower efficiencies than conventional wafer based solar cell technologies. This lesser efficiency is based on a number of reasons, one of which is that with less material, there is less volume for the absorption of incident photons. This shortcoming leads to the need for optical light trapping; which is concerned with admitting the maximum amount of light into the solar cell and keeping the light within the structure for as long as possible. In this thesis, I present the fundamental scientific ideas, practice and methodology behind the application of photonic engineering device concepts to increase the light trapping capacity of thin film solar cells. In the introductory chapters, I develop the basic ideas behind light trapping in a sequential manner, where the effects of the inclusion of various structures on the front and back surfaces of solar cells are examined. This framework is then adapted as a basis for the development of more advanced topics, such as the inclusion of micro and nano scale surface textures, diffraction gratings and photonic bandgap structures. Analyses of the effects of these light trapping structures is undertaken using performance metrics, such as the short circuit current characteristics and a band-edge enhancement factor, which all serve to quantitatively demonstrate the effects of the optical enhancements. I begin this thesis with an investigation of one dimensional photonic crystals, which are used as selective light filters between vertically stacked tandem multi-junction solar cells. These ideas are then further developed for single junction stand alone thin film solar cells, where the optical enhancement is shown to be very significant. A further investigation on the application of engineered photonic crystal materials as angular selective light filters is then presented; these filters are shown to overcome the physical limitations of light trapping that are imposed by the optical properties of materials; specifically limitations associated with total internal reflection. In the next part of this thesis, I present a fundamental redesign approach to multiple period distributed Bragg reflectors (DBR's) and their applications to solar cell light trapping. As it turns out, multiple period DBR's, which are required for high back surface reflectance - which is especially necessary in thin film solar cells - present formidable challenges in terms of cost and complexity when considered for high volume manufacturing. To this end, I show that when a single period DBR is combined with a phase matching and metallic layer, the combined structure can achieve high back surface reflectance that is comparable to that of a DBR structure with many more layers. This new structure reduces the back reflector complexity and is hence, amenable to large scale fabrication processes. In the latter sections of this thes

Mutitu, James Gichuhi

207

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%.

208

Light Trapping in Thin Film Silicon Solar Cells on Plastic Substrates  

Science.gov (United States)

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 130-140C. At 130C 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%.

de Jong, M. M.

2013-01-01

209

Embedded biomimetic nanostructures for enhanced optical absorption in thin-film solar cells.  

Science.gov (United States)

Light-management is critical to thin film solar cells due to their usually limited optical absorption in the active layer. Conventional approaches involve employing separate techniques for anti-reflection and light trapping. Here, we demonstrate an embedded biomimetic nanostructure (EBN) that achieves both effects for hydrogenated amorphous silicon (a-Si:H) solar cells. The fabrication of EBNs is accomplished by patterning an index-matching silicon-nitride layer deposited on a glass substrate using polystyrene nanospheres lithography, followed by reactive ion etching. The profile of EBN is then reproduced layer by layer during the deposition of a-Si:H cells. We show that a solar cell with an optimized EBN exhibits a broadband enhanced external quantum efficiency due to both anti-reflection and light-trapping, with respect to an industrial standard cell using an Asahi U glass substrate which is mostly optimized for light trapping. Overall, the cell with an optimized EBN achieves a large short-circuit current density of 17.74 mA/cm(2), corresponding to a 37.63% enhancement over a flat control cell. The power conversion efficiency is also increased from 5.36% to 8.32%. Moreover, the light management enabled by the EBN remains efficient over a wide range of incident angles up to 60, which is particularly desirable for real environments with diffused sun light. The novel patterning method is not restricted to a-Si:H solar cells, but is also widely applicable to other thin film materials. PMID:21747544

Tsai, Min-An; Han, Hao-Wei; Tsai, Yu-Lin; Tseng, Ping-Chen; Yu, Peichen; Kuo, Hao-Chung; Shen, Chang-Hong; Shieh, Jia-Min; Lin, Shiuan-Huei

2011-07-01

210

Effect of CdCl2 annealing treatment on CdS thin films and CdTe/CdS thin film solar cells  

International Nuclear Information System (INIS)

In order to study the effect of CdCl2 annealing treatment on thin CdS films and CdTe/CdS thin film solar cells, a comparative study was carried out on three types of CdTe/CdS solar cells, which had different kinds of CdS window layer: as-deposited CdS, air-annealed CdS without CdCl2 pre-coating, and CdCl2-annealed CdS. When annealed in air the CdS film was partially oxidated to CdO and CdSO4. These oxides increased the series resistance of the CdTe solar cell and led to the lowest fill factor. The presence of CdCl2 on the surface of a CdS thin film during heat treatment in air protected it from oxidation and promoted the recrystallization of the CdS film, resulting in large and closely packed grains with a grain size of ? 50 -150 nm. CdTe/CdS solar cell with such a kind of CdS window layer showed the largest short circuit current and highest conversion efficiency of 12.4%. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

211

Effect of CdCl{sub 2} annealing treatment on CdS thin films and CdTe/CdS thin film solar cells  

Energy Technology Data Exchange (ETDEWEB)

In order to study the effect of CdCl{sub 2} annealing treatment on thin CdS films and CdTe/CdS thin film solar cells, a comparative study was carried out on three types of CdTe/CdS solar cells, which had different kinds of CdS window layer: as-deposited CdS, air-annealed CdS without CdCl{sub 2} pre-coating, and CdCl{sub 2}-annealed CdS. When annealed in air the CdS film was partially oxidated to CdO and CdSO{sub 4}. These oxides increased the series resistance of the CdTe solar cell and led to the lowest fill factor. The presence of CdCl{sub 2} on the surface of a CdS thin film during heat treatment in air protected it from oxidation and promoted the recrystallization of the CdS film, resulting in large and closely packed grains with a grain size of {proportional_to} 50 -150 nm. CdTe/CdS solar cell with such a kind of CdS window layer showed the largest short circuit current and highest conversion efficiency of 12.4%. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Bai, Zhizhong; Wan, Lei; Hou, Zerong; Wang, Deliang [Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2011-02-15

212

Fabrication of thin film nanocrystalline silicon solar cell with low light-induced degradation  

Energy Technology Data Exchange (ETDEWEB)

Nanocrystalline silicon thin films have been deposited at different total gas flow rates and plasma excitation frequencies and samples with similar crystalline volume fraction have been compared. In hydrogenated nanocrystalline silicon solar cells, amorphous component is not necessarily the only determining factor for light-induced degradation. Smaller grain size less than 3 nm diameter and intermediate range order provide a better stability in the i-layer near the p/i interface, thus improving the overall stability of the solar cell. Light-induced degradation (LID) of efficiency of the cell mainly depends on the light-induced degradation of short-circuit current density and light-induced degradation of fill factor (FF). Degradation of open-circuit voltage is less than 1%. Minimum degradation of efficiency obtained in this work is 2%. (author)

Chowdhury, Amartya; Mukhopadhyay, Sumita; Ray, Swati [Energy Research Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)

2009-05-15

213

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

Directory of Open Access Journals (Sweden)

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.

Boccard Mathieu

2014-07-01

214

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

Science.gov (United States)

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.

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

2014-07-01

215

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

OpenAIRE

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, ...

Maurizio, Fabio

2012-01-01

216

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

CERN Document Server

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...

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

2013-01-01

217

N/I buffer layer for substrate microcrystalline thin film silicon solar cell  

Science.gov (United States)

The influence of the substrate surface morphology on the performance of microcrystalline silicon solar cells in the substrate or n-i-p (nip) configuration is studied in this paper. The experiments are carried out on glass substrates coated with naturally textured films of ZnO deposited by low pressure chemical vapor deposition which serves as backcontact and as template for the light trapping texture. The film surface morphology can be modified with a plasma treatment which smoothens the V-shaped valleys to a more U-shaped form. We investigate, first, the influence of different substrates morphologies on the performance of microcrystalline (?c-Si:H) thin film silicon solar cells deposited by very high frequency plasma enhanced chemical vapor deposition. The V-shaped morphologies are found to have strong light trapping capabilities but to be detrimental for the ?c-Si:H material growth and lead to degraded open circuit voltage (Voc) and fill factor (FF) of the solar cells. Hence, in Sec. III B, we introduce a buffer layer with a higher amorphous fraction between the n doped and intrinsic layer. Our study reveals that the buffer layer limits the formation of voids and porous areas in the ?c-Si:H material on substrates with strong light trapping capabilities. Indeed, this layer mitigates Voc and FF losses which enhances the performance of the ?c-Si:H solar cell. Finally, by applying our findings, we report an efficiency of 9% for a nip ?c-Si:H thin film silicon cell with a thickness of only 1.2 ?m.

Sderstrm, T.; Haug, F.-J.; Terrazzoni-Daudrix, V.; Niquille, X.; Python, M.; Ballif, C.

2008-11-01

218

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

Directory of Open Access Journals (Sweden)

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.

Pfeiffer W.

2013-03-01

219

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

Science.gov (United States)

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.

Omelyanovich, M.; Ovchinnikov, V.; Simovski, C.

2015-02-01

220

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

CERN Document Server

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.

Omelyanovich, Mikhail; Simovski, Constantin

2014-01-01

221

Hybrid light trapping structures in thin-film silicon solar cells  

Science.gov (United States)

Enhancing light absorption in thin-film silicon solar cells is important for improving efficiency and reducing cost. We introduce a hybrid light trapping structure, where front grating and backside Ag nanoparticles are optimized for antireflection and light trapping. The solar cell with this optimized structure yields a photocurrent of 29.7 mA cm-2 within an active layer equivalent thickness of 1 ?m, close to the theoretical limit. This approach is robust to various incident angles and is applicable to different thicknesses in the range of a few micrometers. Two other similar hybrid structures are also proved to be effective light trapping schemes. Moreover, we illustrate that the device implementation could be realized in low-cost technologies.

Shi, Yanpeng; Wang, Xiaodong; Liu, Wen; Yang, Tianshu; Yang, Fuhua

2014-07-01

222

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

Science.gov (United States)

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

Park, Seungil; Parida, Bhaskar; Kim, Keunjoo

2013-05-01

223

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

Science.gov (United States)

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

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

2013-12-01

224

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?1100 cm2/V s, and holes are in the range of 100101 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.

225

Electrical impact of MoSe2 on CIGS thin-film solar cells.  

Science.gov (United States)

The CIGS solar cell is one of the most promising photovoltaic devices due to the achievement of the highest conversion efficiency (>20%) among all thin-film solar cells. The CIGS cell has a glass/Mo/CIGS/CdS/TCO configuration, and the CIGS-Mo interface is a Schottky barrier to holes. During the sulfurization-after-selenization (SAS) CIGS formation process with H2Se gas, the Mo surface transforms naturally into MoSe2 at the CIGS-Mo interface. In this work, the electrical impact of MoSe2 on CIGS solar cells was investigated. Different CIGS-Mo interfaces were prepared with two CIGS processes. One is SAS, and the other is the sequential-sputtering-selenization CIGS process with Se gas. Formation of MoSe2 is hardly observed in the latter process. Samples were characterized by XRD, the van der Pauw method, reflectance, and visual inspection. Besides, Schottky barrier heights of cells were extracted from J-V-T measurements. For the first time, it was experimentally shown that the existence of thin MoSe2 film can decrease the apparent Schottky barrier height of CIGS solar cells. In addition, 1-dimensional numerical simulation showed that a larger barrier height affects both the fill factor and open-circuit voltage. Therefore, the formation of MoSe2 during the CIGS process should minimize the negative effect of Schottky barrier on solar-cell performances, especially with large Schottky barrier. PMID:24068110

Hsiao, Kuo-Jui; Liu, Jing-Da; Hsieh, Hsing-Hua; Jiang, Ting-Shiuan

2013-11-01

226

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

Science.gov (United States)

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.

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

2014-08-01

227

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in english 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 m). 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 m, 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.

J., Sastr-Hernndez; M.E., Calixto; M., Tufio-Velzquez; G., Contreras-Puente; A., Morales-Acevedo; G., Casados-Cruz; M.A., Hernndez-Prez; M.L., Albor-Aguilera; R., Mendoza-Prez.

2011-10-11

228

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

Directory of Open Access Journals (Sweden)

Full Text Available Polycrystalline Cu(In,GaSe2 (CIGS solar cells are attractive because low cost techniques can be used to obtain high efficiency thin film photovoltaic devices. Several research groups around the world have developed CIGS/CdS solar cells with efficiencies larger than 15% [1] using evaporation, making it an attractive and reliable technique for thin film deposition. Our PVD system is provided with MBE-type Knudsen cells to deposit CIGS thin films on glass/Molibdenum (Mo substrates. The deposition conditions for each metal source have been established by doing a deposition profile of temperature data vs. growth rate by co-evaporation to obtain CIGS thin film for solar cells. Characterization of the co-evaporated CIGS thin films was performed by X-ray diffraction (X-RD, scanning electron microscopy (SEM and energy dispersive x-ray spectroscopy (EDS techniques. Good quality polycrystalline films were obtained as shown by X-RD patterns. SEM micrographs show films having a very uniform appearance with large grain sizes (1 m. 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 m, 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.

J. Sastr\\u00E9-Hern\\u00E1ndez

2011-01-01

229

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

Science.gov (United States)

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.

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

2014-05-01

230

Peel-and-stick: fabricating thin film solar cell on universal substrates.  

Science.gov (United States)

Fabrication of thin-film solar cells (TFSCs) on substrates other than Si and glass has been challenging because these nonconventional substrates are not suitable for the current TFSC fabrication processes due to poor surface flatness and low tolerance to high temperature and chemical processing. Here, we report a new peel-and-stick process that circumvents these fabrication challenges by peeling off the fully fabricated TFSCs from the original Si wafer and attaching TFSCs to virtually any substrates regardless of materials, flatness and rigidness. With the peel-and-stick process, we integrated hydrogenated amorphous silicon (a-Si:H) TFSCs on paper, plastics, cell phone and building windows while maintaining the original 7.5% efficiency. The new peel-and-stick process enables further reduction of the cost and weight for TFSCs and endows TFSCs with flexibility and attachability for broader application areas. We believe that the peel-and-stick process can be applied to thin film electronics as well. PMID:23277871

Lee, Chi Hwan; Kim, Dong Rip; Cho, In Sun; William, Nemeth; Wang, Qi; Zheng, Xiaolin

2012-01-01

231

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 600nm. 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 (c-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)

232

Titanium oxide thin film improving efficiency in polymer/fullerene solar cells  

Energy Technology Data Exchange (ETDEWEB)

Full text. Polymer/fullerene based solar cells are of great interest in polymer-based photovoltaic due to low cost fabrication in large areas and on flexible substrates, and roll-to-roll manufacturing. Standard power conversion efficiencies of about 5 - 8% are reported in such organic photovoltaic cells (OPVC) but in order to improve device performance new materials and device architectures are needed. Our OPVC thin films consists of blend of P3HT-PCBM (1:1 by weight) and are spin-coated over indium tin oxide (ITO)-glass substrate covered with poly(3,4-ethylenedioxylenethiophene) polystyrene sulfonic acid (PEDOT:PSS) forming the hole electrode. The collector electrode is a lower-work-function metal, which is in our case Al. Many papers reported the use of lithium fluoride (LiF) layer for a better ohmic contact, but this insulating layer can also reduce the electron collection efficiency if its thickness is above few nanometers. From current-voltage curves in dark and under illumination we show an improvement in the fill factor (FF) and better quality of an OPVC when LiF layer is replaced by titanium oxide (TiO) thin film. The final device is annealed to 150 deg C well below the crystallization temperature for TiO{sub 2} (anatase), resulting in an amorphous phase of this oxide but keeping good conductive quality.

Feu, W.H.M.; Martins, R.F.; Krambrock, K.; Cury, L.A.; Guimaraes, P.S.S. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisica; Reis, G.A.; Franchello, F.; Dias, I.F.L. [Universidade Estadual de Londrina (UEL), PR (Brazil). Dept. de Fisica

2011-07-01

233

Material aspects of ZnO to make surface texture growth for light trapping for thin film solar cells  

Energy Technology Data Exchange (ETDEWEB)

The efficiency of thin film solar cells can be increased through the process of light trapping by having thin films of surface-textured transparent conducting oxides (as a window and back contact), and particularly by using doped zinc oxide (ZnO) for this. Apart from aiming at high electrical conductivity and high optical transmission in the visible light range, the growth of ZnO films with textured surfaces is of main interest in the context of thin-film solar cells. In this work, we present the material aspects of ZnO that play an important role in growing ZnO films with textured surfaces. The surface texture growth of ZnO under different deposition conditions, by both sputtering and by chemical vapour deposition (CVD), is presented. (orig.)

Selvan, J.A.A.; Keppner, H.; Kroll, U.; Cuperus, J.; Shah, A. [Neuchatel Univ. (Switzerland). Inst. de Microtechnique; Adatte, T. [Neuchatel Univ. (Switzerland). Inst. de Geologie; Ketterer, C. [Centre Suisse d' Electronique et de Microtechnique SA, Neuchatel (Switzerland)

1997-07-01

234

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

235

Tailoring randomly rough textures for light trapping in thin-film solar cells  

Science.gov (United States)

In this contribution, we use a rigorous electro-optical model to study randomly rough crystalline silicon solar cells with the absorber thickness ranging from 1 to 100 ?m. We demonstrate a significant efficiency enhancement, particularly strong for thin cells. We estimate the "region of interest" for thin-film photovoltaics, namely the thickness range for which the energy conversion efficiency reaches maximum. This optimal thickness results from the opposite trends of current and voltage as a function of the absorber thickness. Finally, we focus on surface recombination. In our design, the cell efficiency is limited by recombination at the rear (silicon absorber/back reflector) interface, and therefore engineering the front surface to a large extent does not reduce the efficiency. The presented model of roughness adds a significant functionality to previous approaches, for it allows performing rigorous calculations at a much reduced computational cost.

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

2014-05-01

236

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

Science.gov (United States)

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

Li, Wei; Varlamov, Sergey; Xue, Chaowei

2014-09-01

237

Surface Plasmon Polaritons in Metallic Nanostructures: Fundamentals and Their Application to Thin-Film Solar Cells  

Science.gov (United States)

A surface plasmon polariton is a hybrid excitation where the electromagnetic field is resonantly coupled to a free carrier oscillation in noble metals. Once excited, a large enhancement of the local electromagnetic field and the amount of scattered light can be observed. Since both properties are beneficial for the purpose ofphoton management, in the past several years an increasing share of research was devoted to exploit such effects in solar cells. In this contribution, we review the fundamentals of surface plasmon polaritons and outline different approaches how to incorporate metallic nanostructures into solar cells. We detail to which extent they are useful to enhance the solar cell efficiency and describe different schemes for their experimental implementation. Emphasis is put on thin-film solar cells, since in this class of solar cells metallic nanostructures may have the largest impact. This chapter is written with the intention to make researchers from either the field of plasmonics or the field of photovoltaics familiar with their respective counterpart to foster research in this applied domain.

Rockstuhl, Carsten; Fahr, Stephan; Lederer, Falk

238

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.

239

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

Science.gov (United States)

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.

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

2012-06-01

240

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.

241

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

Science.gov (United States)

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.

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

2014-10-01

242

Interfacial alkali diffusion control in chalcopyrite thin-film solar cells.  

Science.gov (United States)

Alkali elements, specifically sodium (Na), are key materials to enhance the energy conversion efficiencies of chalcopyrite and related thin-film photovoltaic solar cells. Recently, the effect of potassium (K) has also attracted attention because elemental K has unique effects different from Na as well as a similar beneficial effect in improving device performance. In this study, the control of selective alkali K and Na diffusion into chalcopyrite thin-films from soda-lime glass substrates, which serve as the monolithic alkali source material and contain both K and Na, is demonstrated using ternary CuGaSe2. Elemental K is found to be incorporated in the several ten nanometer thick Cu-deficient region, which is formed on the CuGaSe2 film surface, while Na is ejected, although both K and Na diffuse from the substrate to the CuGaSe2 film surface during growth. The alkali [K]/[Na] concentration ratio in the surface region of CuGaSe2 films strongly depends on the film structure and can be controlled by growth parameters under the same substrate temperature conditions. The results we present here offer new concepts necessary to explore and develop emerging new chalcopyrite and related materials and optimize their applications. PMID:25004458

Ishizuka, Shogo; Yamada, Akimasa; Fons, Paul J; Shibata, Hajime; Niki, Shigeru

2014-08-27

243

Three dimensionally structured interdigitated back contact thin film heterojunction solar cells  

Science.gov (United States)

Three dimensionally structured thin film photovoltaic devices based on interdigitated arrays of microscale electrodes are examined by external quantum efficiency simulations, indicating considerable JSC enhancement is possible through elimination of the front contact and window layer required in planar geometry devices. Electrode parameters including, pitch, width, height, and material are modeled and experimentally probed, demonstrating experimentally and capturing in models dependence on intrinsic material properties and electrode dimensions. In contrast to analogous silicon wafer back contact solar cells where the electrodes are placed on the silicon absorber at the end of processing, in this design the semiconductor is deposited on the electrodes, taking advantage of the thin film processing already required. Electrodeposited CdS/CdTe heterojunction devices approach 1% efficiencies with simulations as well as optical measurements indicating significant potential for improvement. Suboptimal performance is attributed to unintended materials reactions that preclude annealing at the temperatures required for absorber optimization as well as the Schottky barrier formation on the nonoptimal electrode materials. The test bed structures and absorber synthesis processes are amenable to an array of deposition techniques for fabrication and measurements of three dimensionally structured semiconductors, contact materials, and photovoltaic devices subject to processing feasibility and materials compatibility.

Hangarter, C. M.; Hamadani, B. H.; Guyer, J. E.; Xu, H.; Need, R.; Josell, D.

2011-04-01

244

Ag-doped CuGaSe 2 as a precursor for thin film solar cells  

Science.gov (United States)

For the preparation of p-CuGaSe 2 thin film absorbers, powder of single-phase CuGaSe 2 with defined optical and electrical properties is required as precursor material for solar cells. The motivation for this work was that thin films shall be produced by a chemical vapour transport method using iodine as transport agent. Here we report on an optimised synthesis method of this precursor material and discuss the effect of Ag-doping using Ag, AgSe 2 and AgJ as dopants. Crystalline material was characterised by intensity-dependent photoluminescence (PL), X-ray diffraction (XRD) and time resolved microwave conductivity (TRMC). PL-measurements at T=10 K of undoped CuGaSe 2 show a dominating emission at E=1.67 eV which is attributed to a free-to-bound transition where the acceptor bound state is assigned to copper vacancies. Ag-doped samples showed a dominating emission at E=1.61 eV which is attributed to a donor acceptor pair-transition with copper vacancies as acceptors and selenium vacancies as donors. XRD-measurements showed good single-phase quality of CuGaSe 2. TRMC-measurements reveal an increase of the hole mobility of Ag-doped material compared to undoped CuGaSe 2.

Weiss, T.; Birkholz, M.; Saad, M.; Bleyhl, S.; Kunst, M.; Jger-Waldau, A.; Lux-Steiner, M. Ch.

1999-03-01

245

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

Science.gov (United States)

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.

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

2015-03-01

246

Perovskite solar cells based on nanocolumnar plasma-deposited ZnO thin films.  

Science.gov (United States)

ZnO thin films having a nanocolumnar microstructure are grown by plasma-enhanced chemical vapor deposition at 423 K on pre-treated fluorine-doped tin oxide (FTO) substrates. The films consist of c-axis-oriented wurtzite ZnO nanocolumns with well-defined microstructure and crystallinity. By sensitizing CH3NH3PbI3 on these photoanodes a power conversion of 4.8% is obtained for solid-state solar cells. Poly(triarylamine) is found to be less effective when used as the hole-transport material, compared to 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD), while the higher annealing temperature of the perovskite leads to a better infiltration in the nanocolumnar structure and an enhancement of the cell efficiency. PMID:24643984

Ramos, F Javier; Lpez-Santos, Maria C; Guilln, Elena; Nazeeruddin, Mohammad Khaja; Grtzel, Michael; Gonzalez-Elipe, Agustin R; Ahmad, Shahzada

2014-04-14

247

Thin film solar energy collector  

Science.gov (United States)

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.

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

1983-11-22

248

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

International Nuclear Information System (INIS)

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

249

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

Science.gov (United States)

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

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

2002-01-01

250

Research on polycrystalline thin-film CuGaInSe2 solar cells  

Science.gov (United States)

This report describes research to fabricate high-efficiency CdZnS/CuInGaSe2 (CIGS) thin-film solar cells, and to develop improved transparent conductor window layers such as ZnO. A specific technical milestone was the demonstration of an air mass (AM) 1.5 global, 13 percent efficient, 1-sq cm total-area CIGS thin-film solar cell. Our activities focused on three areas. First, a CIGS deposition system was modified to double its substrate capacity, thus increasing throughput, which is critical to speeding the process development by providing multiple substrates from the same CIGS run. Second, new tooling was developed to enable an investigation of a modified aqueous CdZnS process. The goal was to improve the yield of this critical step in the device fabrication process. Third, our ZnO sputtering system was upgraded to improve its reliability, and the sputtering parameters were further optimized to improve its properties as a transparent conducting oxide. The characterization of the new CIGS deposition system substrate fixturing was completed, and we produced good thermal uniformity and adequately high temperatures for device-quality CIGS deposition. Both the CIGS and ZnO deposition processes were refined to yield a ZnO / Cd(0.82)Zn(0.18)S / CuIn(0.80)Ga(0.20)Se2 cell that was verified at NREL under standard testing conditions at 13.1 percent efficiency with V(sub oc) = 0.581 V, J(sub sc) = 34.8 mA/sq cm, FF = 0.728, and a cell area of 0.979 sq cm.

Stanbery, B. J.; Chen, W. S.; Devaney, W. E.; Stewart, J. W.

1992-11-01

251

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

Energy Technology Data Exchange (ETDEWEB)

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)

Tiwari, A. N.; Romanyuk, Y.

2010-01-15

252

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 FabryPerot resonance effect. (paper)

253

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

CERN Document Server

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...

Israelowitz, Miriam; Cong, Tao; Sureshkumar, Radhakrishna

2013-01-01

254

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%.

255

Absorbance enhancement of thin film solar cells with front double dielectric and back metallic grating  

Science.gov (United States)

We present finite difference time domain (FDTD) and rigorous coupled-wave analysis (RCWA) simulations to analyze the optical absorption enhancement of thin film solar cells (TFSCs) employing front double dielectric and back plasmonic grating structures. Simulation results show that the combination of a subwavelength aperture and a double nano-structured dielectric grating with back triangle metallic grating results in an enhancement in total optical absorption. The absorption of the planar structure is enhanced thanks to an increase of the optical path length of the red and near-infrared photons, causing a proportional enhancement of the absorption in this spectral range. 90.85% Average harvesting (on TE and TM) can be achieved by the optimized structure in the spectrum range from 300 to 1100 nm. The designed SC has high integrated absorption and is weakly dependent on incident angle, which should be useful for application in film photovoltaics, photodetectors and infrared imaging.

Zheng, Gaige; Zhang, Wei; Xu, Linhua; Chen, Yunyun; Liu, Yuzhu

2014-11-01

256

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.

257

Selective ablation of thin Mo and TCO films with femtosecond laser pulses for structuring thin film solar cells  

International Nuclear Information System (INIS)

We report on recent results on selective ablation of TCO (SnO2,ZnO) and metallic layers as a possible process for structuring thin film solar cells. The multipulse ablation thresholds determined for substrate and various thin films show a parameter window where the films can be completely removed by a single scan without at the same time damaging the underlying material. By employing ultrashort pulsed lasers, nonthermal ablation at repetition rates up to the megahertz regime enables high quality structuring combined with process speeds meeting industrial demands. (orig.)

258

Roll to roll fabrication process of thin film silicon solar cells on steel foil  

Energy Technology Data Exchange (ETDEWEB)

ECN is developing a novel fabrication process for thin film silicon solar cells on steel foil. Key features in this process chain are: (1) application of an insulating barrier layer which enables texturization of the rear contact with submicron structures for light trapping; (2) Si deposition with remote, linear PECVD; and (3) series interconnection by laser scribing and printing after deposition of the layers (reducing the total number of process steps). The barrier layer is primarily an enabler for monolithic series interconnection of cells, but we show that we can also fabricate any arbitrary sub-micron structure in this layer by hot embossing to achieve optimum light trapping in the solar cells. For deposition of doped and intrinsic silicon layers we use novel remote and linear plasma sources, which are excellently suited for continuous rollto- roll processing. We have been able to fabricate devicequality amorphous and microcrystalline silicon layers with these sources. First pin a-Si solar cells have been made on FTO glass, yielding initial efficiencies up to 4.5%. First n-i-p a-Si cells made on steel foil plus textured barrier layer yielded efficiencies of about 3.7%.

Van Aken, B.B.; Doerenkaemper, M.; Devilee, C.; Heijna, M.C.R.; Loeffler, J.; Soppe, W.J. [ECN Solar Energy, Petten (Netherlands)

2009-06-15

259

Roll to roll fabrication process of thin film silicon solar cells on steel foil  

Energy Technology Data Exchange (ETDEWEB)

ECN is developing a novel fabrication process for thin film silicon solar cells on steel foil. Key features in this process chain are: (1) application of an insulating barrier layer which enables texturization of the rear contact with submicron structures for light trapping; (2) Si deposition with remote, linear PECVD; (3) series interconnection by laser scribing and printing after deposition of the layers (reducing the total number of process steps). The barrier layer is primarily an enabler for monolithic series interconnection of cells, but we show that we can also fabricate any arbitrary sub-micron structure in this layer by hot embossing to achieve optimum light trapping in the solar cells. For deposition of doped and intrinsic silicon layers we use novel remote and linear plasma sources, which are excellently suited for continuous roll-to-roll processing. We have been able to fabricate device-quality amorphous and microcrystalline silicon layers with these sources. First pin a-Si solar cells have been made on FTO glass, yielding initial efficiencies up to 4.5%. First nip a-Si cells made on steel foil plus textured barrier layer yielded efficiencies of about 3.7%.

Soppe, W.J.; Van Aken, B.B.; Doerenkaemper, M.S.; Devilee, C.; Heijna, M.; Loeffler, J. [ECN Solar Energy, Petten (Netherlands)

2009-09-15

260

Overview and Challenges of Thin Film Solar Electric Technologies  

Energy Technology Data Exchange (ETDEWEB)

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.

Ullal, H. S.

2008-12-01

261

Plasmonic rear reflectors for thin-film solar cells: design principles from electromagnetic modelling  

Science.gov (United States)

The use of plasmonic structures to enhance light trapping in solar cells has recently been the focus of significant research, but these structures can be sensitive to various design parameters or require complicated fabrication processes. Nanosphere lithography can produce regular arrays of nanoscale features which could enhance absorption of light into thin films such as those used in novel solar cell designs. Finite-difference-time-domain simulations are used to model a variety of structures producible by this technique and compare them against the use of mirrors as rear reflectors. Through analysis of these simulations, sensitivity of device performance to parameters has been investigated. Variables considered include the feature size and array period, as well as metal and absorber materials selection and thickness. Improvements in idealized photocurrent density are calculated relative to the use of rear mirrors that are a standard for solar cells. The maximum simulated increase to photocurrent density was 3.58mA/cm2 or 21.61% for a 2?m thick Si cell relative to the case where a silver mirror is used as a rear reflector. From this, an initial set of design principles for such structures are developed and some avenues for further investigation are identified.

Disney, Claire E. R.; Pillai, Supriya; Johnson, Craig M.; Xu, Qi; Green, Martin A.

2014-10-01

262

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%.

263

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.

264

Correlation between Microstructure and Photovoltaic Performance of Polycrystalline Silicon Thin Film Solar Cells  

Science.gov (United States)

Intrinsic polycrystalline silicon (poly-Si) thin films have been prepared by plasma enhanced chemical vapor deposition at a very high excitation frequency (100 MHz) for the development of p-i-n junction solar cells. The correlation between poly-Si microstructure and photovoltaic performance of poly-Si solar cells has been investigated as a function of deposition parameters such as deposition pressure, SiH4 flow rate and SiH4 concentration. It is found that the poly-Si microstructure including crystalline volume fraction, Xc, and crystallographic orientation is closely related to the atomic hydrogen flux during film growth, which is evidenced by plasma diagnostics in the in situ measurement of optical emission spectroscopy. Basically, with an increase in Xc, open circuit voltage tends to decrease, while poly-Si with Xc > 50% and (220) preferential orientation is essential for high short circuit current. Based on these results, the role of poly-Si microstructure in the photovoltaic performance of poly-Si solar cells is discussed.

Matsui, Takuya; Tsukiji, Masaharu; Saika, Hiroyuki; Toyama, Toshihiko; Okamoto, Hiroaki

2002-01-01

265

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

Science.gov (United States)

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

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

2014-12-10

266

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2014-09-15

267

Dyadic Greens functions of thin films: Applications within plasmonic solar cells  

DEFF Research Database (Denmark)

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 Greens function formulation. Based on the dyadic Greens function (Greens 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 Greens 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.

Jung, Jesper; Sndergaard, Thomas

2011-01-01

268

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.

269

Efficient simulation of plasmonic structures for thin film silicon solar cells  

Energy Technology Data Exchange (ETDEWEB)

Thin film silicon solar cells suffer from the disadvantage of a low absorption coefficient of silicon in important spectral regions. In the case of a flat multilayer cell layout a considerable part of the incident light is reflected back out of the cell due to the low absorber thickness. It is therefore desirable to introduce scattering elements that prolong the average photon path length inside the solar cell's absorber. Plasmonic structures are an upcoming area of research in this field. They might be better suited for optimization than other means of light trapping. The influences of periodic arrays of metal scatters on cell absorption can be very well assessed by different simulation methods. We employ the finite element method for 3D simulations of Maxwell's equations. The setup for our simulations has been proposed by Rockstuhl et al. who numerically studied absorption enhancement in a thin bulk of amorphous silicon due to scattering on a periodic array of silver discs. Using the same setup we show that our method is very time and memory efficient for the simulation of such plasmonic structures. Absorption enhancement is shown for wavelengths above 500 nm compared to the absorption without silver discs.

Lockau, Daniel [Helmholtz-Zentrum Berlin, Berlin (Germany); Zuse-Institut Berlin, Berlin (Germany); Burger, Sven; Zschiedrich, Lin; Schmidt, Frank [Zuse-Institut Berlin, Berlin (Germany); JCMwave GmbH, Berlin (Germany); Rech, Bernd [Helmholtz-Zentrum Berlin, Berlin (Germany)

2010-07-01

270

CIGSS Thin Film Solar Cells: Final Subcontract Report, 10 October 2001-30 June 2005  

Energy Technology Data Exchange (ETDEWEB)

This report describes the I-III-VI2 compounds that are developing into a promising material to meet the energy requirement of the world. CuInSe2 (CIS) and its alloy with Ga and S have shown long-term stability and highest conversion efficiency of 19.5%. Among the various ways of preparing CuIn1-xGaxSe2-ySy (CIGSS)/CdS thin-film solar cells, co-evaporation and sputtering techniques are the most promising. Sputtering is an established process for very high-throughput manufacturing. ARCO Solar, now Shell Solar, pioneered the work in CIS using the sputtering technique. The two-stage process developed by ARCO Solar involved sputtering of a copper and indium layer on molybdenum-coated glass as the first step. In the second step, the copper-indium layers were exposed to a selenium-bearing gas such as hydrogen selenide (H2Se) mixed with argon. The hydrogen selenide breaks down and leaves selenium, which reacts and mixes with the copper and indium in such a way to produce very high-quality CIS absorber layer. Sputtering technology has the added advantage of being easily scaled up and promotes roll-to-roll production on flexible substrates. Preliminary experiments were carried out. ZnO/ZnO:Al deposition by RF magnetron sputtering and CdS deposition by chemical-bath deposition are being carried out on a routine basis.

Dhere, N. G.

2006-02-01

271

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

272

Roll to roll fabrication of thin film silicon solar cells on nano-textured substrates.  

Science.gov (United States)

ECN is developing a novel fabrication process for thin film silicon solar cells on steel foil. Key features in this process are: (1) application of an insulating barrier layer which enables monolithic interconnection and texturization of the rear contact with submicron structures for light trapping; (2) Si deposition with remote, linear PECVD; (3) series interconnection by laser scribing and printing after deposition of all layers, which reduces the total number of process steps. The barrier layer is essential for the monolithic series interconnection of cells, but we show that it also enables optimum light trapping in the solar cells. We can fabricate any arbitrary sub-micron surface profile by hot embossing the barrier layer. For deposition of doped and intrinsic silicon layers we use novel remote, linear plasma sources, which are excellently suited for continuous roll-to-roll processing. We have been able to fabricate device-quality amorphous and microcrystalline silicon layers with these sources. The first nip a-Si cells were made on steel substrates with flat barrier layer and had initial efficiencies of 6.3%, showing the potential of the concept. PMID:22408957

Soppe, W J; Borg, H; Van Aken, B B; Devilee, C; Drenkmper, M; Goris, M; Heijna, M C R; Lffler, J; Peeters, P

2011-12-01

273

Surface textured ZnO:Al thin films by pulsed DC magnetron sputtering for thin film solar cells applications  

Science.gov (United States)

Transparent conducting thin films of ZnO:Al (Al-doped ZnO, AZO) were prepared via pulsed DC magnetron sputtering with good transparency and relatively lower resistivity. The AZO films with 800 nm in thickness were deposited on soda-lime glass substrates keeping at 473 K under 0.4 Pa working pressure, 150 W power, 100 ?s duty time, 5 ?s pulse reverse time, 10 kHz pulse frequency and 95% duty cycle. The as-deposited AZO thin films has resistivity of 6.39 10 -4 ? cm measured at room temperature with average visible optical transmittance, Ttotal of 81.9% under which the carrier concentration and mobility were 1.95 10 21 cm -3 and 5.02 cm 2 V -1 s -1, respectively. The films were further etched in different aqueous solutions, 0.5% HCl, 5% oxalic acid, 33% KOH, to conform light scattering properties. The resultant films etched in 0.5% HCl solution for 30 s exhibited high Ttotal = 78.4% with haze value, HT = 0.1 and good electrical properties, ? = 8.5 10 -4 ? cm while those etched in 5% oxalic acid for 150 s had desirable HT = 0.2 and relatively low electrical resistivity, ? = 7.9 10 -4 ? cm. However, the visible transmittance, Ttotal was declined to 72.1%.

Yen, W. T.; Lin, Y. C.; Ke, J. H.

2010-11-01

274

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

International Nuclear Information System (INIS)

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

275

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

OpenAIRE

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

Franken, R. H. -j

2006-01-01

276

Indium phosphide/cadmium sulfide thin-film solar cells. Semiannual report, July 1980-December 1980  

Energy Technology Data Exchange (ETDEWEB)

InP thin films were deposited by planar reactive deposition on recyrstallized CdS (RXCdS) and semi-insulating (100) InP substrates and evaluated as potential layers for an all-thin-film solar cell. Films prepared on RXCdS at approximately 330/sup 0/C contained a mixture of grains having both large and submicron lateral dimensions. SIMS analysis showed the interdiffusion profiles to be well behaved and, within the resolution of the analysis, no significant difference in the profiles between structures prepared at 330/sup 0/C and 380/sup 0/C. Be-doped epitaxial films, deposited on semi-insulating InP at 330/sup 0/C, showed both n- and p-type behavior. Films prepared at higher and lower temperatures with a freshly Be-charged In source were p-type and n-type, respectively; the n-type behavior is associated with an excess of n-type native defects. SIMS analyses confirmed the presence of Be in all Be-doped films. Growth with deviation from stoichiometry was initiated at 330/sup 0/C to reduce the concentration of native defects. Growth of Be-doped films at higher substrate temperature with the same Be-doped source after several runs eventually resulted in n-type films. Analyses of the In source and films were initiated to determine the cause of the transient doping. As an alternative to Be doping, p-type Zn-doped InP films were prepared on InP semi-insulating substrates with room-temperature carrier concentration and mobilities of 6 x 10/sup 16/ cm/sup -3/, and 80 cm/sup 2//Vsec, respectively.

Zanio, K.

1981-03-01

277

Surface treatments and properties of CuGaSe2 thin films for solar cell applications  

International Nuclear Information System (INIS)

Polycrystalline CuGaSe2 (CGS) films with slightly Ga-rich composition were prepared on Mo/soda-lime substrates by the 'bi-layer' process. The film surfaces were modified by chemical bath treatment with In2(SO4)3, thioacetamid, and triethanolamin to improve the performance in solar cell applications. The film compositions were characterized by X-ray fluorescence and the surface of treated films was investigated by X-ray photoelectron spectroscopy (XPS). Solar cells with ZnO/CdS/CGS/Mo/soda-lime glass structure were fabricated, and the current-voltage properties and the quantum efficiency were analyzed. Improvement of the spectral response, especially in the long wavelength region, was observed for the samples treated with the chemical bath, which results in increase in a short circuit current density. An increase in the parallel and series resistance of the cells was also observed with the treatment. The surface compositions of the CGS thin films modified by the chemical bath are discussed on the base of the results of XPS

278

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 6080 C in air for 1 h to improve ohmic contact. Analysis of JV 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

279

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

Science.gov (United States)

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

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

2014-05-01

280

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

Science.gov (United States)

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.

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

2015-02-01

281

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

Directory of Open Access Journals (Sweden)

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.

Walder Cordula

2015-01-01

282

Inverted polymer solar cells with sol-gel derived cesium-doped zinc oxide thin film as a buffer layer  

Science.gov (United States)

An inverted structure of polymer solar cells based on Poly(3-hexylthiophene)(P3HT):[6-6] Phenyl-(6) butyric acid methyl ester (PCBM) with thin films of sol-gel derived Cesium doped ZnO (Cs:ZnO) was developed as an efficient cathode buffer layer. Doped and undoped thin films were deposited using a less studied method, doctor blade, which was compatible with Roll-2-Roll printing method. By comparing the effect of Cs:ZnO thin films with various dopant ratio on the performance of inverted polymer solar cells, 0.5% Cs doped ZnO was found as the most effective doping level among the selected doping ratios. Using 30 nm thickness of 0.5% Csn:ZnO thin film as an electron transport layer led to the average efficiency which was significantly higher than (9%) that of similar devices employing the same thickness of undoped ZnO film. Results showed that the devices fabricated with 1% and 2% cesium doped ZnO yielded lower power conversion efficiency, which could be due to the lower FF. Also, the influence of dopant incorporation on the optical transmittance and electrical conductivity of ZnO films was investigated.

Ahmadi, Mehdi; Mirabbaszadeh, Kavoos; Salari, Saeid; Fatehy, Hamed

2014-09-01

283

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)

284

Thin film silicon solar cells for space applications: Study of proton irradiation and thermal annealing effects on the characteristics of solar cells and individual layers  

OpenAIRE

The paper reports on the effects of a proton irradiation campaign on a series of thin-film silicon solar cells (single- and double-junction). The effect of subsequent thermal annealing on solar cells degraded by proton irradiation is investigated. A low-temperature annealing behaviour can be observed (at temperatures around 100 to 160C) for microcrystalline silicon solar cells. To further explore this effect, a second proton irradiation campaign has been carried out, but this time on microc...

Kuendig, J.; Goetz, M.; Shah, Arvind; Gerlach, L.; Fernandez, E.

2008-01-01

285

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

OpenAIRE

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...

So?derstro?m, Karin; Bugnon, Gre?gory; Biron, Re?mi; Pahud, Ce?line; Meillaud, Fanny; Haug, Franz-josef; Ballif, Christophe

2012-01-01

286

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.

287

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

Science.gov (United States)

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.

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

2008-08-01

288

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

Directory of Open Access Journals (Sweden)

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 15100 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.

Yun Jae Sung

2014-07-01

289

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

290

Semi-coherent optical modelling of thin film silicon solar cells  

Energy Technology Data Exchange (ETDEWEB)

At NEXT ENERGY the experimental investigation of thin film silicon solar cells is combined with numerical simulations using the software Sentaurus TCAD from Synopsys. We present the results of optical modelling with Sentaurus TCAD based on the one-dimensional semi-coherent optical model by Janez Krc. The idea of this model is that after interacting with a rough interface the incident light is split into a direct coherent part treated as electromagnetic waves and in a diffuse incoherent part treated as light beams. The proportion of either direct or diffuse part is determined by the haze parameter which can be obtained from spectrometer data. In order to describe the scattering effects at rough interfaces the intensities of the diffuse light are scaled with angular distribution functions. These functions are obtained from angle resolved scattering measurements. The optical model will be verified by experimental data and compared to the Raytracer and the Transfer Matrix Model. Furthermore the influence of different angles of incidence and of the spectral dependency on the solar cell performance will be investigated.

Walder, Cordula; Lacombe, Juergen; Maydell, Karsten von; Agert, Carsten [EWE-Forschungszentrum fuer Energietechnologie e.V., Carl-von-Ossietzky-Strasse 15, 26129 Oldenburg (Germany)

2011-07-01

291

Effect of p-layer properties on nanocrystalline absorber layer and thin film silicon solar cells  

Energy Technology Data Exchange (ETDEWEB)

The influence of the p-layer on the crystallinity of the absorber layer and nanocrystalline silicon thin film solar cells has been studied. Boron doped Si : H p-layers of different crystallinities have been prepared under different power pressure conditions using the plasma enhanced chemical vapour deposition method. The crystalline volume fraction of p-layers increases with the increase in deposition power. Optical absorption of the p-layer reduces as the crystalline volume fraction increases. Structural studies at the p/i interface have been done by Raman scattering studies. The crystalline volume fraction of the i-layer increases as that of the p-layer increases, the effect being more prominent near the p/i interface. Grain sizes of the absorber layer decrease from 9.2 to 7.2 nm and the density of crystallites increases as the crystalline volume fraction of the p-layer increases and its grain size decreases. With increasing crystalline volume fraction of the p-layer solar cell efficiency increases.

Chowdhury, Amartya; Adhikary, Koel; Mukhopadhyay, Sumita; Ray, Swati [Energy Research Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)], E-mail: ray_swati2004@yahoo.co.in

2008-07-07

292

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

Science.gov (United States)

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

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

2015-02-01

293

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

Science.gov (United States)

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

Meng, Xianqin; Depauw, Valrie; Gomard, Guillaume; El Daif, Ounsi; Trompoukis, Christos; Drouard, Emmanuel; Jamois, Ccile; Fave, Alain; Dross, Frdric; Gordon, Ivan; Seassal, Christian

2012-07-01

294

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

Science.gov (United States)

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

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

2014-12-21

295

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

Energy Technology Data Exchange (ETDEWEB)

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})

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

296

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)

297

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

Science.gov (United States)

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 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).

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

2008-05-01

298

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-12-15

299

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)

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.

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

2013-05-01

300

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.

301

Processing and modeling issues for thin-film solar cell devices. Annual subcontract report, January 16, 1993--January 15, 1994  

Energy Technology Data Exchange (ETDEWEB)

The overall objective of the research presented in this report is to advance the development and acceptance of thin-film photovoltaic modules by increasing the understanding of film growth and processing and its relationship to materials properties and solar cell performance. The specific means toward meeting this larger goal include: (1) investigating scalable, cost-effective deposition processes; (2) preparing thin-film materials and device layers and completed cell structures; (3) performing detailed material and device analysis; and (4) participating in collaborative research efforts that address the needs of PV-manufacturers. These objectives are being pursued with CuInSe{sub 2}, CdTe and a-Si based solar cells.

Birkmire, R.W.; Phillips, J.E.; Buchanan, W.A.; Hegedus, S.S.; McCandless, B.E.; Shafarman, W.N.; Yokimcus, T.A. [Institute of Energy Conversion, Newark, DE (United States)

1994-09-01

302

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

Science.gov (United States)

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 350 nm-800 nm, the conversion efficiency of solar cells can be further enhanced.

Wang, Donglin; Su, Gang

2014-11-01

303

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

Science.gov (United States)

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 350 nm-800 nm, the conversion efficiency of solar cells can be further enhanced. PMID:25418477

Wang, DongLin; Su, Gang

2014-01-01

304

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)

305

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. Capacitancevoltage (CV) and currentvoltage measurements were performed. The values of barrier height and carrier concentration were estimated from the reverse bias CV. 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.

306

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

CERN Document Server

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.

Wang, DongLin

2014-01-01

307

Selective ablation of thin films in latest generation CIGS solar cells with picosecond pulses  

Science.gov (United States)

Recent developments in Cu(In,Ga)Se2 (CIGS) thin film photovoltaics enabled the manufacturers to produce highly efficient solar modules. Nevertheless, the production process still lacks a competitive process for module patterning. Today, the industry standard for the serial interconnection of cells is still based on mechanical scribing for the P2 and P3 process. A reduction of the non-productive "dead zone" between the P1 and P3 scribes is crucial for further increasing module efficiency. Compact and affordable picosecond pulsed laser sources are promising tools towards all-laser scribing of CIGS solar modules. We conducted an extensive parameter study comprising picosecond laser sources from 355 to 1064 nm wavelength and 10 to 50 ps pulse duration. Scribing results were analyzed by laser scanning microscope, scanning electron microscope and energy dispersive X-ray spectroscopy. We developed stable and reliable processes for the P1, P2 and P3 scribe. The best parameter sets were then used for the production of functional mini-modules. For comparison, the same was done for a selection of nanosecond pulsed lasers. Standardized analysis of the modules has shown superior electrical performance of the interconnections and confirmed the feasibility of a dead zone width of less than 200 m on an entire mini module.

Burn, Andreas; Romano, Valerio; Muralt, Martin; Witte, Reiner; Frei, Bruno; Bcheler, Stephan; Nishiwaki, Shiro

2012-03-01

308

NANO-IMPRINT TECHNIQUE FOR BACK REFLECTOR IN HIGH EFFICIENCY N-I-P THIN FILM SILICON SOLAR CELLS  

OpenAIRE

In this contribution, the replication of nano-textures enhancing the short circuit current of thin film silicon solar cells onto low cost substrates (glass or PolyEthylene Naphtalate (PEN)) is studied. Optical and morphological analysis is performed to asses the quality of these replicas. Single and tandem a-Si:H solar cells are deposited on top of the master and replica structures to verify their suitability to be used as substrates for solar cells in substrate (n-i-p) configuration. We find...

So?derstro?m, Karin; Escarre Palou, Jordi; Biron, Re?mi; Eminian, Ce?line; Haug, Franz-josef; Ballif, Christophe; Garcia, Cubero; Jesus, Oscar

2010-01-01

309

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

Energy Technology Data Exchange (ETDEWEB)

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.

Slafer, D.; Dalal, V.

2012-03-01

310

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)

311

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

Science.gov (United States)

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.

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

2015-03-01

312

Simulation approach for studying the performances of original superstrate CIGS thin films solar cells  

International Nuclear Information System (INIS)

In this work, we report on the performances of superstrate Cu(In,Ga)Se2 (CIGS) thin film solar cells with an alternative SLG/SnO2:F/CIGS/In2Se3/Zn structure using AMPS-1D (Analysis of Microelectronic and Photonic structures) device simulator. An inverted surface layer, n-type CIGS layer, is inserted between the In2Se3 buffer and CIGS absorber layers and the SnO2:F layer is just a transparent conducting oxide (TCO). The simulation has been carried out by lighting through SnO2:F. The obtained results show that the existence of so-called 'ordered defect compound' (ODC) layer in such a structure is the critical factor responsible for the optimization of the performances. Photovoltaic parameters were determined using the current density-voltage (J-V) curve. An optimal absorber and ODC layer thickness has been estimated, that improve significantly the devices efficiency exceeding 15% AM1.5 G. The variation of carrier density in In2Se3 layer has an influence on the superstrate CIGS cells performances. Moreover, the quantum efficiency (Q.E.) characteristics display a maximum value of about 80% in the visible range.

313

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

Science.gov (United States)

The intense light scattered from metal nanoparticles sustaining surface plasmons makes them attractive for light trapping in photovoltaic applications. However, a strong resonant response from nanoparticle ensembles can only be obtained if the particles have monodisperse physical properties. Presently, the chemical synthesis of colloidal nanoparticles is the method that produces the highest monodispersion in geometry and material quality, with the added benefits of being low-temperature, low-cost, easily scalable and of allowing control of the surface coverage of the deposited particles. In this paper, novel plasmonic back-reflector structures were developed using spherical gold colloids with appropriate dimensions for pronounced far-field scattering. The plasmonic back reflectors are incorporated in the rear contact of thin film n-i-p nanocrystalline silicon solar cells to boost their photocurrent generation via optical path length enhancement inside the silicon layer. The quantum efficiency spectra of the devices revealed a remarkable broadband enhancement, resulting from both light scattering from the metal nanoparticles and improved light incoupling caused by the hemispherical corrugations at the cells' front surface formed from the deposition of material over the spherically shaped colloids. PMID:25760231

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

2015-03-27

314

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

Energy Technology Data Exchange (ETDEWEB)

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.

Zhang, Wendi

2013-10-01

315

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

OpenAIRE

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) heterojuncti...

Sun, Leizhi; Haight, Richard; Sinsermsuksakul, Prasert; Bok Kim, Sang; Park, Helen Hejin; Gordon, Roy Gerald

2013-01-01

316

HUMID ENVIRONMENT STABILITY OF LPCVD ZNO:B USED AS TRANSPARENT ELECTRODES IN THIN FILM SILICON SOLAR CELLS  

OpenAIRE

The stability in humid environment of low pressure chemical vapor deposited boron doped zinc oxide (LPCVD ZnO:B) used as transparent conductive oxide in thin film silicon solar cells is investigated. Damp heat treatment (exposition to humid and hot atmosphere) induces a degradation of the electrical properties of unprotected LPCVD ZnO:B layers. By combining analyses of the electrical and optical properties of the films, we are able to attribute this behavior to an increase of electron grain b...

Steinhauser, Je?ro?me; Meyer, Stefan; Schwab, Marle?ne; Fay?, Sylvie; Ballif, Christophe; Kroll, U.; Borrello, D.

2008-01-01

317

Improved Thin Film Solar Cells Made by Vapor Deposition of Earth-Abundant Tin(II) Sulfide  

OpenAIRE

Tin(II) sulfide (SnS) is an earth-abundant, inexpensive, and non-toxic absorber material for thin film solar cells. SnS films are deposited by atomic layer deposition (ALD) through the reaction of a tin precursor, bis(N,N'-diisopropylacetamidinato)tin(II), and hydrogen sulfide. The SnS films demonstrate excellent surface morphology, crystal structure, phase purity, stoichiometry, elemental purity, and optical and electrical properties.

Sun, Leizhi

2014-01-01

318

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

OpenAIRE

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...

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

319

Mimicry of sputtered i-ZnO thin films using chemical bath deposition for solution-processed solar cells.  

Science.gov (United States)

Solution processing provides a versatile and inexpensive means to prepare functional materials with specifically designed properties. The current challenge is to mimic the structural, optical, and/or chemical properties of thin films fabricated by vacuum-based techniques using solution-based approaches. In this work we focus on ZnO to show that thin films grown using a simple, aqueous-based, chemical bath deposition (CBD) method can mimic the properties of sputtered coatings, provided that the kinetic and thermodynamic reaction parameters are carefully tuned. The role of these parameters toward growing highly oriented and dense ZnO thin films is fully elucidated through detailed microscopic and spectroscopic investigations. The prepared samples exhibit bulk-like optical properties, are intrinsic in their electronic characteristics, and possess negligible organic contaminants, especially when compared to ZnO layers deposited by sol-gel or from nanocrystal inks. The efficacy of our CBD-grown ZnO thin films is demonstrated through the effective replacement of sputtered ZnO buffer layers within high efficiency solution processed Cu2ZnSnS4xSe4(1-x) solar cells. PMID:25506738

Della Gaspera, Enrico; van Embden, Joel; Chesman, Anthony S R; Duffy, Noel W; Jasieniak, Jacek J

2014-12-24

320

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 6.8210?3 ?cm and particle grains. The double-layers structure is designed to fabricate the ZnO:In thin film with low resistivity (2.5810?3 ?cm) and good surface morphology. It is found that the surface morphology of the double-layer ZnO:In film strongly depends on the substrate-layer, and the second-layer plays a large part in the resistivity of the double-layer ZnO:In thin film. Both total and direct transmittances of the double-layer ZnO:In film are above 80% in the visible light region. Single junction a-Si:H solar cell based on the double-layer ZnO:In as front electrode is also investigated. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

321

Development of Commercial Technology for Thin Film Silicon Solar Cells on Glass: Cooperative Research and Development Final Report, CRADA Number CRD-07-209  

Energy Technology Data Exchange (ETDEWEB)

NREL has conducted basic research relating to high efficiency, low cost, thin film silicon solar cell design and the method of making solar cells. Two patents have been issued to NREL in the above field. In addition, specific process and metrology tools have been developed by NREL. Applied Optical Sciences Corp. (AOS) has expertise in the manufacture of solar cells and has developed its own unique concentrator technology. AOS wants to complement its solar cell expertise and its concentrator technology by manufacturing flat panel thin film silicon solar cell panels. AOS wants to take NREL's research to the next level, using it to develop commercially viable flat pane, thin film silicon solar cell panels. Such a development in equipment, process, and metrology will likely produce the lowest cost solar cell technology for both commercial and residential use. NREL's fundamental research capability and AOS's technology and industrial background are complementary to achieve this product development.

Sopori, B.

2013-03-01

322

Photoelectrochemical (PEC) solar cell properties of chemically deposited cadmium selenide thin films with heteropolyacids  

Energy Technology Data Exchange (ETDEWEB)

The photoelectrochemical (PEC) solar cell properties of chemically deposited cadmium selenide thin films with heteropolyacids have been studied. It has been shown that the PEC solar cell parameters change with the concentration of silicotungstic acid (STA) or phosphotungstic acid (PTA). The best performances are obtained on the electrodes fabricated with 10{sup -5} M STA or 10{sup -5} M PTA. Without STA or PTA, the CdSe film in 0.45 M SeSO{sub 3}{sup 2-} electrolyte showed an open-circuit voltage (V{sub oc}) of 510 mV, a short circuit photocurrent density (J{sub sc}) of 2.7 mA cm{sup -2}, a fill factor of 0.48 and a cell efficiency ({eta}) of 1.6%. The film when grown with 10{sup -5} M PTA showed the following PEC solar cell parameters: V{sub oc}=570 mW; J{sub sc}=7.6 mA. cm{sup -2}, fill factor, 0.55 and {eta}, 5.9%. The CdSe film deposited with 10{sup -5} M STA showed for superior I-V properties with a V{sub oc} of 600 mV, a J{sub sc} of 11.8 mA. cm{sup -2}, a fill factor of 0.68 and a {eta} of 11.7%. The determination of the chemical composition of the films by X-ray diffraction, XPS and neutron activation analysis have shown the presence of WO{sub 3} in the films deposited with HPAs. The improvements of the PEC solar cell properties have been ascribed to the formation of the n-CdSe/n-WO{sub 3} heterojunction which enhances the charge transfer at the semiconductor/electrolyte interface. These results indicated for the first time the interesting effects of STA and PTA on the chemically deposited CdSe films. This opens up a new method to develop mixed electrodes having improved physical properties and PEC solar cells performances. (orig.).

Savadogo, O.; Mandal, K.C. (Dept. de Metallurgie et de Genie des Materiaux, Ecole Polytechnique de Montreal, Quebec (Canada))

1992-06-01

323

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2008-05-01

324

Polycrystalline silicon thin film solar cells prepared by PECVD-SPC  

Energy Technology Data Exchange (ETDEWEB)

Among the most promising technological alternatives for the development of photovoltaic modules and cells of a low cost, good energetic conversion and feasibility for mass production, polycrystalline silicon thin film solar cells deposited directly on a transparent substrate are currently being considered the best. We have developed in our laboratory a PECVD reactor capable of producing the deposition of amorphous hydrogenated silicon at rates of above 2 nm/seg, allowing a significant production per line on the plant. Discharge gas is silane, to which diborane or phosphine is added so as to form the cell. Basically, work is done on a structure of cell type TCO/n+/p-/p+/M, which has 2 {mu}m of total thickness. Schott AF-37 glass is used as a substrate, for their ability to withstand temperatures of up to 800 C. The amorphous cell is subsequently annealed at gradual temperatures of 100 C to achieve dehydrogenation up to 650-700 C for 12 h until their complete crystallization is achieved. Our results show a complete crystallization of silicon with a grain size of less than a micron, with a dehydrogenation process at 500 C, leaving a remainder of less than 1% in hydrogen as monohydrate. The parameters of the cell estimated from the IV curve yield low values, FF<0.55, Icc <200 {mu}A and Voc<420 mV. The high series resistance is due to the grain size and defect density, which will be attempted to be improved by post-hydrogenation and rapid thermal annealing (RTA) methods at high temperatures. (author)

Buitrago, R.H.; Risso, G.A.; Cutrera, M.; Battioni, M.; De Bernardez, L.; Schmidt, J.A.; Arce, R.D.; Koropecki, R.R. [Instituto de Desarrollo Tecnologico para la Industria Quimica, CONICET-UNL, Guemes 3450, CP 3000, Santa Fe (Argentina)

2008-07-15

325

Processing and modeling issues for thin-film solar cell devices: Annual subcontract report, January 16, 1995 -- January 15, 1996  

Energy Technology Data Exchange (ETDEWEB)

The overall mission of the Institute of Energy Conversion is the development of thin film photovoltaic cells, modules, and related manufacturing technology and the education of students and professionals in photovoltaic technology. The objectives of this four-year NREL subcontract are to advance the state of the art and the acceptance of thin film PV modules in the areas of improved technology for thin film deposition, device fabrication, and material and device characterization and modeling, relating to solar cells based on CuInSe{sub 2} and its alloys, on a-Si and its alloys, and on CdTe. In the area of CuInSe{sub 2} and its alloys, EEC researchers have produced CuIn{sub 1-x}GaxSe{sub 2} films by selenization of elemental and alloyed films with H{sub 2}Se and Se vapor and by a wide variety of process variations employing co-evaporation of the elements. Careful design, execution and analysis of these experiments has led to an improved understanding of the reaction chemistry involved, including estimations of the reaction rate constants. Investigation of device fabrication has also included studies of the processing of the Mo, US and ZnO deposition parameters and their influence on device properties. An indication of the success of these procedures was the fabrication of a 15% efficiency CuIn{sub 1-x}GaxSe{sub 2} solar cell.

Birkmire, R W; Phillips, J E; Buchanan, W A; Eser, E; Hegedus, S S; McCandless, B E; Meyers, P V; Shafarman, W N [Univ. of Delaware, Newark, DE (United States)

1996-08-01

326

Efficiency limitations of polycrystalline thin film solar cells: case of Cu(In,Ga)Se2  

International Nuclear Information System (INIS)

Small-area Cu(In,Ga)Se2 thin film solar cells have reached more than 19% efficiencies. Compared to other polycrystalline materials this efficiency value is remarkable. Nevertheless, the 19% for Cu(In,Ga)Se2 range more than 6% (absolute) below the world's best single-crystalline Si cells and almost 14% below the upper theoretical limit of 33% for an ideal black body cell with infinitely large mobility and radiative recombination only. About 4% out of the 14% are of optical nature, additional 3% stem from the limited mobility/diffusion length and from band gap fluctuations with a standard deviation no. sigmano. gno. approxno. 50 meV due to spatial variations of composition and stoichiometry of the quaternary compound Cu(In,Ga)Se2. Thus, about 26% efficiency would be possible if there were only these band gap fluctuations. Additional, voltage-dependent electrostatic potential fluctuations push down the efficiency further to 19%: The polycrystalline Cu(In,Ga)Se2 which is unavoidably structurally inhomogeneous due to dislocations, grain boundaries, point defects, etc. is also electrostatically inhomogeneous because of charged defects. Electrostatic potential fluctuations at the valence and conduction band edge may be not only responsible for a high saturation current density but also for the ideality factor in the current/voltage curve. The band gap and electrostatic potential fluctuations make the effective band gap wfluctuations make the effective band gap which controls the intrinsic carrier density smaller than the average optical gap. The (zero bias) electrostatic potential fluctuations are here derived from the ideality factors of the current/voltage curve. The ideality factor reflects the voltage-induced electrostatic homogenization of the sample. For the world's best Cu(In,Ga)Se2 cells with an ideality factor of n id=1.5, we estimate zero bias electrostatic potential fluctuations with a standard deviation no. sigmano. elecno. approxno. 140 meV

327

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

Science.gov (United States)

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. PMID:25811493

Tait, Jeffrey G; De Volder, Michal F L; Cheyns, David; Heremans, Paul; Rand, Barry P

2015-04-01

328

Experimental study of Cu2ZnSn(Se,S)4 thin films for solar cell applications  

OpenAIRE

Cu2ZnSn(Se,S)4 (CZT(Se,S)) has recently been shown to be a promising material to use in thin film solar cells. It has a band gap of between 1eV (CZTSe) and 1.5eV (CZTS). CZT(Se,S) solar cells have reached 10% efficiency. The aim of this project was to find an effective way to selenise metallic Cu, Zn, Sn films in order to produce Cu2ZnSnSe4 (CZTSe) films, without destroying the metallic molybdenum (Mo) back contact. Another aim was to make films containing both Se and S and to study the po...

Engman, Jessica

2011-01-01

329

Optimized nano-textured interfaces for thin-film silicon solar cells: identifying the limit of randomly textured interfaces  

Science.gov (United States)

Thin-film solar cells contain nano-textured interfaces that scatter the incident light, leading to increased absorption and hence increased current densities in the solar cell. In this manuscript we systematically study optimized random nano-textured morphologies for three different cases: amorphous hydrogenated silicon solar cells (a-Si:H, bandgap 1.7 eV), nano-crystalline silicon solar cells (nc-Si:H, bandgap 1.1 eV) and tandem solar cells consisting of an a-Si:H and a nc-Si:H junction. For the optimization we use the Perlin texture algorithm, the scalar scattering theory, and a semi-coherent optical device simulator.

Jger, Klaus; Linssen, Dane N. P.; Isabella, Olindo; Zeman, Miro

2014-05-01

330

Cu (In,Ga)Se2 thin films and solar cells prepared by selenization of metallic precursors  

International Nuclear Information System (INIS)

CuIn(1-x)GaxSe2 (CIGS) thin films with Ga ratio, x, ranging from 0.55 to 0.75 were grown on Mo/glass substrates by the selenization of metallic precursors in a H2Se atmosphere. Without a postdeposition annealing step the films were found to have a highly graded composition that became Ga rich near the absorber/Mo interface. A high-temperature annealing step promoted diffusion of Ga to the surface region of the films. These absorbers were used to fabricate glass/Mo/CIGS/CdS/ZnO thin-film solar cells with open-circuit voltages ranging from 0.4 to 0.74 V and efficiencies approaching 12%. Devices, as well as the absorber layers, were characterized. copyright 1996 American Vacuum Society

331

Progress toward 20% efficiency in Cu(In,Ga)Se{sub 2} polycrystalline thin-film solar cells  

Energy Technology Data Exchange (ETDEWEB)

This short communication reports on achieving 18.8% total-area conversion efficiency for a ZnO/CdS/Cu(In,Ga)Se{sub 2}/Mo polycrystalline thin-film solar cells. We also report a 15%-efficient, Cd-free device fabricated via physical vapor deposition methods. The Cd-free cell includes no buffer layer, and it is fabricated by direct deposition of ZnO on the Cu(In,Ga)Se{sub 2} thin film absorber. Both results have been measured at the National Renewable Energy Laboratory under standard reporting conditions (1000 W/m{sup 2}, 25degC, ASTM E 892 Global). The 18.8% conversion efficiency represents a new record for such devices (Notable Exceptions) and makes the 20% performance level by thin-film polycrystalline materials much closer to reality. We allude to the enhancement in performance of such cells as compared to previous record cells, and we discuss possible and realistic routes to enhance the performance toward the 20% efficiency level. (Author)

Contreras, Miguel A.; Egaas, Brian; Ramanathan, K.; Swartzlander, A.; Hasoon, F.; Noufi, Rommel [National Renewable Energy Lab., Golden, CO (United States); Hiltner, J. [Colorado State Univ., Dept. of Physics, Fort Collins, CO (United States)

1999-07-01

332

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

333

Doped and multi-compound ZnO-based transparent conducting oxides for silicon thin film solar cells  

OpenAIRE

[eng] The objective of the present work is to provide a better understanding of magnetron sputtered transparent conducting oxides based on ZnO in order to use them as electrodes in thin film silicon solar cells at the Grup d'Energia Solar of the Universitat de Barcelona. This thesis presents the properties of magnetron sputtered aluminium and gallium doped ZnO as well as the properties of multi-compound materials deposited by the co-sputtering of zinc oxide and indium tin oxide. The applicati...

Carreras Segui?, Paz

2013-01-01

334

Characterization of CdS/CdTe and CdS/CuInSe2 thin film solar cells  

Science.gov (United States)

A study on low cost polycrystalline thin film CdS/CdTe and CdS/CuInSe2 solar cells using measurements of spectral response and capacitance-voltage-frequency relationships was performed. Because of high concentrations of localized levels in the energy gap existing in materials and at interfaces, the redistribution of charge among the levels due to illumination plays an important role in the collection of light-generated current in these cells. The results illustrate some related phenomena observed in these cells.

Cheng, L. J.; Nguyen, T. T.; Shyu, C. M.; Basol, B. M.; Yoo, H. I.

1984-01-01

335

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

OpenAIRE

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...

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

2008-01-01

336

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

Energy Technology Data Exchange (ETDEWEB)

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.

Baier, Robert

2012-06-25

337

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

Science.gov (United States)

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

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

2014-03-01

338

Cd-free heterojunctions in chalcopyrite based thin film solar cells; Cd-freie Heterokontakte in Chalkopyrit-basierten Duennschichtsolarzellen  

Energy Technology Data Exchange (ETDEWEB)

This thesis took care of the problem to replace the buffer layers Cds and i-ZnO in thin-film solar cells of the layer system p-Cu(In,Ga)(Se,S){sub 2}/CdS/i-ZnO/n{sup +} by a Cd-free buffer layer. The synthesis of the material layers. The synthesis was carried out by the method of cathode sputtering established in the deposition of the n{sup +}-ZnO window layer. Aim was to modify the electronic properties of the studied materials either by the choice of the applied bonding elements or by the choice of the composition in such a way that the basic conditions for buffer layers are fulfilled: Optical transparency and suited band fitting to the absorber material. The analysis of the interfaces between the potential buffer materials and the Cu(In,Ga)(Se,S){sub 2} absorber material considering the conduction-band fitting important for solar cells formed a main topic. Finally suited materials came into application as buffer layers in Cu(In,Ga)(Se,S){sub 2}-based thin-film solar cells. Thereby was of interest, whether efficient solar cells can be fabricated, and whether the photovoltaic parameters open-circuit voltage and short-circuit current density are dominantly influenced by possible interface defects, as they are especially discussed in connection with the sputtering deposition.

Kieven, David

2012-02-06

339

Thin-Film Silicon Solar Cells with Integrated Metal Nanoparticles and Metal Nanostructures for an Enhanced Light Absorption - Impedance Measurements and Simulations of Thin-Film Solar Cells  

OpenAIRE

Photovoltaic technology offers the possibility of environmentally friendly production of electricity based on an almost infinite source of energy, the sun. Today most commercially available solar cells are made of crystalline or polycrystalline silicon. Such solar cells can achieve efficiencies of up to 24.7 % for unconcentrated light. However, their disadvantages are the high material cost and the high energy consumption during production...

Moulin, Etienne

2009-01-01

340

Impacts of electron irradiation on the optical and electrical properties of CIGS thin films and solar cells  

International Nuclear Information System (INIS)

Full text : A thin film solar cell composed of polycrystalline Cu(In,Ga)Se2 (CIGS) is essentially light-weight and shows high conversion efficiency and excellent radiation tolerance. These characteristics lead to CIGS solar cells very attractive for space applications. However, only a few irradiation studies have been carried out on CIGS thin films and entire solar cell structure, resulting in limited knowledge on the mechanisms responsible for the irradiation-induced damage. In addition, the cell performance is known to change due to the damp heat and/or light soaking effects. Accordingly, understanding the degradation mechanisms of CIGS, ZnO, a buffer, Mo, and even glass components is necessary for not only space use but also commercial use. In this presentation, electron irradiation effects will be discussed for CIGS solar cells and each layer that composed the CIGS solar cell structure such as CIGS, CdS, undoped ZnO, and Ga- or Al-doped ZnO films. Electron irradiation experiments were carried out using the DYNAMITRON electron accelerator. The electron energy was fixed at 2 MeV and the fluence was varied between 1 * 1013 and 1 * 1018 cm-2. All the irradiated CIGS films exhibited common PL peaks originating from donor to acceptor transitions. PL peak intensity due to Cu-related point defects, which did not affect solar cell performance significantly, increased in CIGS thin films with increasing electron irradiation. Converth increasing electron irradiation. Conversely, transmittance spectra of all the irradiated ZnO and ZnO:Al films did not change by the electron irradiation up to 6 * 1017 cm-2. The normalized performance parameters of the irradiated CIGS solar cell such as Voc, Jsc, and ? are shown in article as a function of irradiation fluence. ? tended to decrease in comparison with Voc and Jsc for large irradiation fluence. Shunt resistance and series resistance of the CIGS solar cells degraded even though the resistivity of each layer did not change after electron irradiation. The result indicates that CdS/CIGS interface or another heterojunction tended to degrade easily in comparison with each bulk of solar cell composed of semiconductors

341

Thin film silicon solar cells for space applications. Study of proton irradiation and thermal annealing effects on the characteristics of solar cells and individual layers  

Energy Technology Data Exchange (ETDEWEB)

The paper reports on the effects of a proton irradiation campaign on a series of thin-film silicon solar cells (single- and double-junction). The effect of subsequent thermal annealing on solar cells degraded by proton irradiation is investigated. A low-temperature annealing behaviour can be observed (at temperatures around 100 to 160C) for microcrystalline silicon solar cells. To further explore this effect, a second proton irradiation campaign has been carried out, but this time on microcrystalline silicon layers. The effect of proton irradiation and subsequent thermal annealing on the optical and electronic properties of microcrystalline silicon is, thus, thoroughly investigated.

Kuendig, J.; Goetz, M.; Shah, A. [Institute of Microtechnology (IMT), Thin-film silicon and Photovoltaic group, University of Neuchatel, A.-L. Breguet 2, 2000 Neuchatel (Switzerland); Gerlach, L.; Fernandez, E. [ESA-ESTEC, Keplerlaan 1, NL 2200 AG Noordwijk, The (Netherlands)

2003-09-30

342

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

Energy Technology Data Exchange (ETDEWEB)

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

Woerdenweber, Jan

2011-09-26

343

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%

344

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.

345

Quadruple-junction thin-film silicon-based solar cells with high open-circuit voltage  

Science.gov (United States)

We have fabricated a-SiOx:H/a-Si:H/nc-Si:H/nc-Si:H quadruple-junction thin-film silicon-based solar cells (4J TFSSCs) to obtain high spectral utilization and high voltages. By processing the solar cells on micro-textured superstrates, extremely high open-circuit voltages for photovoltaic technology based on thin-film silicon alloys up to 2.91 V have been achieved. Optical simulations of quadruple-junction solar cells using an advanced in-house model are a crucial tool to effectively tackle the challenging task of current matching among the individual sub-cells in such devices. After optimizing the optical design of the device and the absorber thicknesses, an energy conversion efficiency of 11.4% has been achieved. The open-circuit voltage, short-circuit current density, and fill factor were 2.82 V, 5.49 mA/cm2, and 73.9%, respectively. Based on this demonstration, strategies for further development of highly efficient 4J TFSSCs are proposed.

Si, Fai Tong; Kim, Do Yun; Santbergen, Rudi; Tan, Hairen; van Swaaij, Ren A. C. M. M.; Smets, Arno H. M.; Isabella, Olindo; Zeman, Miro

2014-08-01

346

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 (1.57eV) Cu(InxGa1?x)S2 (CIGS) solar cell showed a high open-circuit voltage of 787mV, whereas the low-band-gap (1.12eV) Cu(InxGa1?x)(S1?ySey)2 (CIGSSe) cell exhibited a high short-circuit current density of 32.6mAcm?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)

347

Solution-processed highly efficient Cu2ZnSnSe4 thin film solar cells by dissolution of elemental Cu, Zn, Sn, and Se powders.  

Science.gov (United States)

Solution deposition approaches play an important role in reducing the manufacturing cost of Cu2ZnSnSe4 (CZTSe) thin film solar cells. Here, we present a novel precursor-based solution approach to fabricate highly efficient CZTSe solar cells. In this approach, low-cost elemental Cu, Zn, Sn, and Se powders were simultaneously dissolved in the solution of thioglycolic acid and ethanolamine, forming a homogeneous CZTSe precursor solution to deposit CZTSe nanocrystal thin films. Based on high-quality CZTSe absorber layer, pure selenide CZTSe solar cell with a photoelectric conversion efficiency of 8.02% has been achieved without antireflection coating. PMID:25494493

Yang, Yanchun; Wang, Gang; Zhao, Wangen; Tian, Qingwen; Huang, Lijian; Pan, Daocheng

2015-01-14

348

Light-scattering effectiveness of two-dimensional disordered surface textures in thin-film silicon solar cells.  

Science.gov (United States)

To compare the light-scattering effectiveness of surface-textured solar cells of various design parameters such as density, diameter, refractive index, and location, this study used a new parameter, optical path length gain (OPLG), that is more sensitive than Haze. By modeling two-dimensional disordered textures as a structure that comprises many randomly distributed, small, spherical scatterers, ray-tracing simulations of surface-textured thin-film silicon solar cells were performed. The simulation results suggest that: (1) the optimal scatterer diameter for hydrogenated amorphous silicon (a-Si:H) solar cells is ~50 nm, producing an average OPLG of 3.5; and (2) the optimal scatterer diameter for a-Si:H/?c-Si:H (hydrogenated microcrystalline silicon) tandem cells is ~75 nm, producing an average OPLG of 3.4 and an increase in the bandwidth of the absorption spectrum of 14.5%. PMID:24921870

Yeh, Pinghui S; Chen, Chien-Wei; Yang, Bing-Ru; Hong, Lu-Sheng

2014-05-01

349

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)

350

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

Science.gov (United States)

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 faade, 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.

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

2014-01-01

351

Low pressure chemical vapor deposited Zinc Oxide for thin film silicon solar cells: optical and electrical properties  

OpenAIRE

Transparent conductive oxides (TCO), such as LPCVD ZnO:B (low pressure chemical vapor deposited zinc oxide doped with boron), play a major role as contacts in thin film silicon photovoltaic solar cells. This document study the "LPCVD ZnO:B layers, from the deposition process to the final application" and focus especially on their electrical and optical properties. This work intended on understanding the physics of the LPCVD ZnO:B film properties in order to efficiently optimize its characteri...

Steinhauser, Je?ro?me; Ballif, Christophe

2009-01-01

352

The optical near-field of randomly textured light trapping structures for thin-film solar cells  

Science.gov (United States)

Randomly textured zinc oxide surfaces with and without amorphous silicon deposited on top are studied by near-field scanning optical microscopy. By virtue of a three dimensions it allows to access the local light intensity in the entire spatial domain above the structures. Measurements are compared with large scale finite-difference time-domain simulations. This study provides new insight into light trapping in thin-film silicon solar cells on a nanoscopic scale. Light localization on the surface of the textured interface and a focusing of light by the structure further away are observed as the key features characteristic for such surfaces.

Beckers, T.; Bittkau, K.; Rockstuhl, C.; Fahr, S.; Lederer, F.; Carius, R.

2008-04-01

353

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

Czech Academy of Sciences Publication Activity Database

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 ostatn: 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

Neykova, Neda; Hruka, Karel; Reme, Zden?k; Van??ek, Milan

354

Ion-beam and plasma etching of a conical-pores photonic crystal for thin-film solar cell  

Science.gov (United States)

Conical holes bored in the active layer of a thin-film silicon solar cell by ion-beam lithography (IBL) show increase of effective optical absorption in the underlying silicon active layer. The optical properties are numerically simulated by the 3D finite-difference time-domain method (3D-FDTD), showing wideband increase of the UV, visible, and IR quantum efficiency. An experimental fabrication procedure is developed using IBL for high wide- area repeatability. A further optimization on the cone shapes is performed in order to make fabrication feasible with plasma etching techniques.

Gervinskas, Gediminas; Rosa, Lorenzo; Juodkazis, Saulius

2013-12-01

355

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

CERN Document Server

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.

Aeberhard, Urs

2014-01-01

356

Rapid crystallization of amorphous silicon utilizing a very-high-frequency microplasma jet for Si thin-film solar cells  

Energy Technology Data Exchange (ETDEWEB)

The rapid crystallization of amorphous silicon utilizing a very-high-frequency thermal microplasma jet of argon is demonstrated. Highly crystallized microcrystalline Si films were fabricated on textured a-Si:H:B/SnO{sub 2}/glass by adjusting the translational velocity of the substrate stage. The crystallization of amorphous silicon was promoted from the bottom surface with no significant inter diffusions of B and Sn from Si:H:B/SnO{sub 2} layers to intrinsic crystallized Si layer. The preliminary result of p-i-n Si thin-film solar cell is demonstrated using the microcrystalline Si films fabricated by the plasma annealing. (author)

Saha, Jhantu Kumar [Japan Science and Technology Agency (JST), 2-1-6 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Haruta, Koji; Yeo, Mina; Shirai, Hajime [The Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama 338-8570 (Japan); Koabayshi, Tomohiro [The Institute of Physics and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

2009-06-15

357

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.

358

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

Science.gov (United States)

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.

Lauzurica, S.; Llusc, M.; Canteli, D.; Snchez-Aniorte, M. I.; Lpez-Vidrier, J.; Hernndez, S.; Bertomeu, J.; Molpeceres, C.

2014-10-01

359

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 lightmatter interaction of these nanostructures is given by localized surface plasmons and, thus, the measured diffuse reflectance of the back contacts is attributed to plasmon-induced light scattering. A significant plasmonic light-trapping effect in n-i-p substrate-type ?c-Si:H thin-film solar cell prototypes which apply a Ag back contact with non-ordered nanostructures is identified when compared with flat reference solar cells

360

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

Science.gov (United States)

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 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.

Wang, Fei; Chen, Xin-liang; Geng, Xin-hua; Zhang, De-kun; Wei, Chang-chun; Huang, Qian; Zhang, Xiao-dan; Zhao, Ying

2012-09-01

361

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

DEFF Research Database (Denmark)

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.

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

2011-01-01

362

Enhanced performance of flexible nanocrystalline silicon thin-film solar cells using seed layers with high hydrogen dilution.  

Science.gov (United States)

Flexible hydrogenated nanocrystalline (nc-Si:H) thin-film solar cells were prepared by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD), and the effect of highly crystalline intrinsic Si seed layers at the initial growth stage of i nc-Si:H absorbers on their structural and electrical properties and on the performance of solar cells was investigated. The crystallization of i nc-Si:H absorbers was significantly enforced by the introduction of highly crystalline seed layers, resulting in the reduction of defect-dense a-Si:H grain boundary and incubation layer thickness. The open circuit voltage of the nc-Si:H solar cells with the seed layers was improved by the decrease of charged defect density in the defect-rich amorphous region. PMID:24266159

Lee, Ji-Eun; Kim, Donghwan; Yoon, Kyung Hoon; Cho, Jun-Sik

2013-12-01

363

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

Science.gov (United States)

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.

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

2015-04-01

364

Nanoimprinted backside reflectors for a-Si:H thin-film solar cells: critical role of absorber front textures.  

Science.gov (United States)

The development of optimal backside reflectors (BSRs) is crucial for future low cost and high efficiency silicon (Si) thin-film solar cells. In this work, nanostructured polymer substrates with aluminum coatings intended as BSRs were produced by positive and negative nanoimprint lithography (NIL) techniques, and hydrogenated amorphous silicon (a-Si:H) was deposited hereon as absorbing layers. The relationship between optical properties and geometry of front textures was studied by combining experimental reflectance spectra and theoretical simulations. It was found that a significant height variation on front textures plays a critical role for light-trapping enhancement in solar cell applications. As a part of sample preparation, a transfer NIL process was developed to overcome the problem of low heat deflection temperature of polymer substrates during solar cell fabrication. PMID:24922373

Tsao, Yao-Chung; Fisker, Christian; Pedersen, Thomas Garm

2014-05-01

365

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.

366

Synthesis and characterization of Zn(O,OH)S and AgInS{sub 2} layers to be used in thin film solar cells  

Energy Technology Data Exchange (ETDEWEB)

In this paper AgInS{sub 2} and Zn(O,OH)S thin films were synthesized and characterized. AgInS{sub 2} 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 AgInS{sub 2} thin films grown with chalcopyrite structure, and the as-grown Zn(O,OH)S thin films were polycrystalline. It was also found that the AgInS{sub 2} films presented p-type conductivity, a high absorption coefficient (greater than 10{sup 4} cm{sup -1}) and energy band-gap E{sub g} of about 1.95 eV, Zn(O,OH),S thin films presented E{sub g} 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 AgInS{sub 2} 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.

Vallejo, W., E-mail: wavallejol@unal.edu.co [Departamento de Quimica, Universidad Nacional de Colombia, Cra 30 No 45-03, Bogota (Colombia); Arredondo, C.A.; Gordillo, G. [Departamento de Fisica, Universidad Nacional de Colombia, Cra 30 No 45-03, Bogota (Colombia)

2010-11-01

367

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

368

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.

369

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)

370

Non-destructive Evaluation of Compound Semiconductor Thin-Film Solar Cells by Photothermal Beam Deflection Technique  

Science.gov (United States)

In this paper, it is demonstrated that the photothermal beam deflection technique can be used for measuring the series resistance, optimum load resistance, and conversion efficiency of thin-film solar cells. This technique is also used for determining the carrier transport properties of an absorber and window layer of -based solar cells during different stages of cell fabrication. Transport properties such as the carrier mobility, lifetime, and surface recombination velocity of the individual absorber and window layer are shown to influence the open-circuit voltage and short-circuit current of the final photovoltaic device. The cell parameters measured using the photothermal technique agree well with the electrical measurements. The principle of the technique is explained on the basis of the "mirage effect" and maximum power transfer theorem.

Warrier, Anita R.; Sebastian, Tina; Kartha, C. Sudha; Vijayakumar, K. P.

2015-01-01

371

Preparation routes based on magnetron sputtering for tungsten disulfide (WS2) films for thin-film solar cells  

International Nuclear Information System (INIS)

The semiconductor tungsten disulfide (WS2) exhibits van der Waals bonding, crystallizes in a layer-type structure and is of interest as an absorber layer for thin-film solar cells. In this review article different preparation routes for WS2 thin films, based on magnetron sputtering, are reviewed. Films prepared by direct magnetron sputtering, though exhibiting quite a good structural quality, are not or only poorly photoactive. This can be attributed to the generation of recombination centers, especially sulfur vacancies, during the ion bombardment of the films, due to the low defect-formation energy of tungsten disulfide, an intrinsic property of transition metal dichalcogenides. A promising preparation route, which leads to photoactive WS2 films, is a two-step process, where, in a first step, a sulfur-rich, X-ray amorphous tungsten sulfide is deposited at low substrate temperatures onto a thin metal film (Ni, Co). This film sandwich is after wards annealed in an ampoule in a sulfur atmosphere or in flowing gas with a sufficient H2S partial pressure. From in-situ transmission electron microscopy and energy-dispersive X-ray diffraction, it was found that the WS2 film crystallization with a pronounced (001) texture is closely related to the formation of the liquid (eutectic) metal-sulfur phase. Based on these in-situ investigations the growth of the 2-dimensional WS2 nanosheets from an amorphous WS3sub> nanosheets from an amorphous WS3+x precursor can be described as an amorphous solid-liquid-crystalline solid process (SLS), somewhat similar to the well-known vapor-liquid-solid (VLS) process for the growth of whiskers or nanorods and nanotubes. Research opportunities, to overcome current limitations for a broad use of WS2 (and MoS2) as thin-film solar cell absorbers are given. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

372

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)

373

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

CERN Document Server

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.

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

2013-01-01

374

Broadband absorption enhancement in a-Si:H thin-film solar cells sandwiched by pyramidal nanostructured arrays.  

Science.gov (United States)

A new thin-film solar cell structure with a broadband absorption enhancement is proposed. The active a-Si:H film is sandwiched by two periodic pyramidal structured layers. The upper dielectric pyramidal layer acts as matching impedance by gradual change of the effective refractive index to enhance the absorption of the active layer in the short wavelength range. The lower metallic pyramidal layer traps light by the excitation of Fabry-Perot (FP) resonance, waveguide (WG) resonance and surface plasmon (SP) mode to enhance the absorption in the long wavelength range. With the cooperation of the two functional layers, a broadband absorption enhancement is realized. The structure parameters are designed by the cavity resonance theory, which shows that the results are accordant with the finite-difference time-domain (FDTD) simulation. By optimizing, the absorption of the sandwich structure is enhanced up to 48% under AM1.5G illumination in the 350-900 nm wavelength range compared to that of bare thin-film solar cells. PMID:23037526

Li, Chuanhao; Xia, Liangping; Gao, Hongtao; Shi, Ruiying; Sun, Chen; Shi, Haofei; Du, Chunlei

2012-09-10

375

The effect of dopant concentration on properties of transparent conducting Al-doped ZnO thin films for efficient Cu2ZnSnS4 thin-film solar cells prepared by electrodeposition method  

Science.gov (United States)

Al-doped ZnO (AZO) thin films were potentiostatically deposited on indium tin oxide substrates. The influence of the doping level of the ZnO:Al films was investigated. The results of the X-ray diffraction and scanning electron microscopy analysis revealed that the structural properties of the AZO films were found polycrystalline with a hexagonal wurtzite-type structure along the (002) plane. The grain size of the AZO films was observed as approximately 3 ?m in the film doping with 4 mol% ZnO:Al concentration. The thin films also exhibited an optical transmittance as high as 90 % in the wavelength range of 100-1,000 nm. The optical band gap increased from 3.33 to 3.45 eV. Based on the Hall studies, the lowest resistivity (4.78 10-3 ? cm) was observed in the film doping with 3 mol% ZnO:Al concentration. The sheet resistant, carrier concentration and Hall mobility values were found as 10.78 ?/ square, 9.03 1018 cm-3 and 22.01 cm2/v s, respectively, which showed improvements in the properties of AZO thin films. The ZnO:Al thin films were used as a buffer layer in thin-film solar cells with the structure of soda-lime glass/Mo/Cu2ZnSnS4/ZnS/ZnO/Al grid. The best solar cell efficiency was 2.3 % with V OC of 0.430 V, J SC of 8.24 mA cm-2 and FF of 68.1 %.

Mkawi, E. M.; Ibrahim, K.; Ali, M. K. M.; Farrukh, M. A.; Mohamed, A. S.

2015-01-01

376

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

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Natively textured surface hydrogenated gallium-doped zinc oxide (HGZO) thin films have been deposited via magnetron sputtering on glass substrates. Black-Right-Pointing-Pointer The directly deposited HGZO thin films present rough crater-type surface morphology. Black-Right-Pointing-Pointer Typical HGZO thin film exhibits a high electron mobility of 41.3 cm{sup 2}/V s and a relative low sheet resistance of {approx}7.0 {Omega}. Black-Right-Pointing-Pointer These HGZO thin films have high optical transmittances in the visible and near infrared region ({approx}380-1100 nm). Black-Right-Pointing-Pointer A gradient H{sub 2} 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 ({lambda} = 380-1100 nm) and excellent electrical properties. The optimized HGZO thin film with crater-type textured surface obtained at the hydrogen flow rate of {approx}2.0 sccm exhibits a high electron mobility of 41.3 cm{sup 2}/V s and a relatively low sheet resistance of {approx}7.0 {Omega}. 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 H{sub 2} 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 H{sub 2} growth technique.

Wang, Fei [Institute of Photo-electronic Thin Film Devices and Technology, Nankai University, Tianjin 300071 (China); Tianjin Key laboratory of Photo-electronic Thin Film Devices and Technology, Nankai University, Tianjin 300071 (China); Key laboratory of Opto-electronic Information Science and Technology for Ministry of Education, Nankai University, Tianjin 300071 (China); Chen, Xin-liang, E-mail: cxlruzhou@163.com [Institute of Photo-electronic Thin Film Devices and Technology, Nankai University, Tianjin 300071 (China); Tianjin Key laboratory of Photo-electronic Thin Film Devices and Technology, Nankai University, Tianjin 300071 (China); Key laboratory of Opto-electronic Information Science and Technology for Ministry of Education, Nankai University, Tianjin 300071 (China); Geng, Xin-hua; Zhang, De-kun; Wei, Chang-chun; Huang, Qian; Zhang, Xiao-dan; Zhao, Ying [Institute of Photo-electronic Thin Film Devices and Technology, Nankai University, Tianjin 300071 (China); Tianjin Key laboratory of Photo-electronic Thin Film Devices and Technology, Nankai University, Tianjin 300071 (China); Key laboratory of Opto-electronic Information Science and Technology for Ministry of Education, Nankai University, Tianjin 300071 (China)

2012-09-01

377

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 (?3801100 nm). ? A gradient H2 growth method for fabricating HGZO thin films has been proposed in magnetron sputtering process. - Abstract: The main purposes are to obtain high quality transparent conductive oxide (TCO) based on zinc oxide (ZnO) thin films with high optical transparency in the visible and near infrared spectral range, high electrical conductivity and good light-scattering capability to enhance the path of the light inside the Si-based thin film solar cells. Natively textured surface hydrogenated gallium-doped ZnO (HGZO) thin films have been deposited via pulsed direct current (DC) magnetron sputtering on glass substrates at a substrate temperature of 553 K. These natively textured HGZO thin films exhibit high optical transmittance (over 80%) in the visible and near infrared region (? = 3801100 nm) and excellent electrical properties. The optimized HGZO thin film with crater-type textured surface obtained at the hydrogen flow rate of ?2.0 sccm 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.

378

Cu(In,Ga)S2, Thin-Film Solar Cells Prepared by H2S Sulfurization of CuGa-In Precursor  

Science.gov (United States)

Thin-film CuInS2 solar cell is the leading candidate for space power because of bandgap near the optimum value for AM0 solar radiation outside the earth's atmosphere, excellent radiation hardness, and freedom from intrinsic degradation mechanisms unlike a-Si:H cells. Ultra-lightweight thin-film solar cells deposited on flexible polyimide plastic substrates such as Kapton(trademark), Upilex(trademark), and Apical(trademark) have a potential for achieving specific power of 1000 W/kg, while the state-of-art specific power of the present day solar cells is 66 W/kg. This paper describes the preparation of Cu-rich CuIn(sub 1-x)Ga(sub x)S(sub 2) (CIGS2) thin films and solar cells by a process of sulfurization of CuGa-In precursor similar to that being used for preparation of large-compact-grain CuIn(sub 1-x)Ga(sub x)Se2 thin films and efficient solar cells at FSEC PV Materials Lab.

Dhere, Neelkanth G.; Kulkarni, Shashank R.; Chavan, Sanjay S.; Ghongadi, Shantinath R.

2005-01-01

379

Development of CdxZn1-xTe alloy thin films for tandem solar cell applications  

International Nuclear Information System (INIS)

We report our development efforts for CdxZn1-xTe alloy thin films for tandem solar cells. We used three aspects of CdTe solar cell fabrication considered key to high performance: high-temperature deposition, post-deposition CdCl2 heat treatment, and use of O2 ambient during device processing. We used bilayers of CdTe and ZnTe as the basis for the formation of CdxZn1-xTe alloy. Use of oxygen at any stage of the processing proved to be problematic due to the formation of ZnO, which resulted in two-phase mixture of CdTe and ZnO. These results can explain the poor performance of CdxZn1-xTe alloy thin-film solar cells reported by several groups. We carried out oxygen free processing of the bilayer stacks and post-deposition heat treatments. Heat treatment in the presence of CdCl2 vapor resulted in the interaction between ZnTe and CdCl2 and the loss of Zn in the form of ZnCl2. Heat treatments of the stack in He ambient resulted in the interdiffusion of the two layers. The composition profiles of the intermixed alloy region were influenced mainly by temperature and the time of the treatment. It is possible to obtain either uniform or graded alloy profiles by adjusting the two parameters. It is possible to adjust the composition of the resulting alloy by adjusting the thickness ratio of CdTe and ZnTe layers. We discuss suitability of the alloy formation usiuss suitability of the alloy formation using the CdTe/ZnTe bilayers for the top cell fabrication of two-junction tandem solar cells. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

380

Effect of load voltage on thin film cuprous sulfide: Cadmium sulfide solar cells thermally cycled in a simulated space environment  

Science.gov (United States)

Thin-film Cu2S-CdS solar cells, loaded at various fixed values of load resistance, were thermally cycled for 1429 cycles in a simulated space environment. Cell performance was measured under controlled conditions in air before and after thermal cycling. These data were used to determine the effect of load voltage on cell performance. The performance of the cells was relatively independent of load voltage up to about 0.39 volt. This appears to be a threshold