14 0 obj 2,3) In comparison, the V OC of the highly efficient GaAs device has achieved 97.7% of the SQ limit with a similar bandgap. CdTe has long been well known as a leading thin-film PV material due to its near optimum bandgap of 1.44 eV and high absorption coefficient. The Digital Object Identifier for the article. << in 2008. 2.4. /odieresis /divide /oslash /ugrave /uacute /ucircumflex /udieresis /yacute /thorn /ydieresis] They employed an aqueous electrolyte solution containing metals salts of CuSO4, ZnSO4, SnSO4, and Na2S2O3 (sulfur source). prism /CrossMarkDomains#5B2#5D (springerlink.com) Recent progress in the development of CdTe TFSCs resulted in remarkable improvements in small-area conversion efficiencies. They found that films electrodeposited from unstirred baths were laterally inhomogeneous with respect to thickness and also composition. By varying the composition of the zinc content, the bandgap was varied between 2.42- 3.7 eV, thereby increasing the cell’s performance in the lower wavelength region, resulting in higher efficiency. Chan et al. A name object indicating whether the document has been modified to include trapping information endobj Conformance level of PDF/A standard CdTe thin film solar cell structure comprises of a p-type CdTe absorber layer and n-type CdS based window layer forming a heterojunction, which has an intermixed interface region. They found in films the presence of precipitates attributed to ZnS phases which contribute to high series resistance and reduced VOC and FF values of solar cell. 18.1. Due to the superstrate nature of CdTe solar cells, the CdTe layer is deposited on top of the CdS layer, often at higher temperatures than at which the CdS was deposited. endobj ID of PDF/X standard /doi (10.1007/s11664-015-3829-y) crossmark /igrave /iacute /icircumflex /idieresis /eth /ntilde /ograve /oacute /ocircumflex /otilde I-V characteristic of a nanopillar with CdS solar cells [22]. Prism Schema http://crossref.org/crossmark/1.0/ CdTe has been shown to be the most promising polycrystalline thin film material for producing PV solar cells because of its high absorption coefficient (α > 10 4 cm −1) and optimum band gap (1.5 eV). Cell Structure The band diagram for the high-efficiency CdTe solar cells at CSU with estimated band offsets is shown in Fig. internal /ZaDb 12 0 R high efficiency CdTe-based thin-film solar cells and on high efficiency a-Si-based thin-film solar cells. The absorber layer is made from direct band gap CdTe TFs. One drawback of very large-scale deployment of CdTe or CuInGaSe2 is the availability of the elemental constituents. Photovoltaic parameters of a CdTe solar cell using the RTP process [21]. URI >> Cu enters the CdTe interstitially forming a shallow donor, Cui centers and gives rise to deep acceptor CuCd centers via substitution [12–15]. A power conversion efficiency of 11.25% was obtained with an open-circuit voltage of 0.72 V, as shown in Table 2.4 [21]. The most successful types have been the heterojunctions where a wide bandgap semiconductor is used as the heterojunction partner or “window.” Cadmium sulfide (CdS) has been the most extensively studied and most apposite window material for CdTe solar cells to date. The improved process involved the use of the Cu/Sn/Cu/Zn sequential stacks, a rotating disk electrode (RDE) for improving the large-scale uniformity of deposited metal layers and a KCN etching solution to remove Cu-rich phases in CZTS thin films [123]. Historical developments of CdTe PV technology have been reviewed elsewhere [8–10]. Several types of CdTe solar cells such as Schottky barrier, homojunction, heterojunction, and p–i–n have been explored to date. 10 0 obj These observations inspired the development of a post deposition treatment (PDT) which led to increased efficiencies of >20% [16–18]. Another material that has been developed for thin film solar cells is copper indium gallium diselenide (CuInGaSe2, sometimes known as CIGS). However, developing a stable low-resistivity back contact to the CdTe solar cells is still an issue. Moreover, the perovskite solar cells can be deposited by low-temperature methods such as solution process viz. /Oslash /Ugrave /Uacute /Ucircumflex /Udieresis /Yacute /Thorn /germandbls /agrave /aacute There are various methods to deposit CdTe which includes close-spaced sublimation (CSS), vapor transport deposition, electrodeposition, physical vapor deposition, sputtering, etc. O’Connor and D. Phillips, Time-Correlated Single Photon Counting (Academic Press, San Diego, CA, 1984). B The acute health effects from inhalation of Cd include pneumonitis, pulmonary edema, and death and such effects are also associated with soluble cadmium compounds like CdCl2. part external However, in the state-of-the-art CdTe solar cells, the open-circuit voltage (V OC) is 880 mV, which is only 76.1% of the Shockley–Queisser (SQ) limit of 1157 mV. In the first step, we modified the conventional cell structure by substituting the CdS window layer with a CdS:O film having a wide band gap ranging from 2.42 to 3.17 eV. CdTe-based thin-film solar cell modules currently represent one of the fastest-growing segments of commercial module production. Fig. endobj In this study, a new CdTe solar cell structure was proposed, where Zinc Cadmium Sulfide (Zn. Therefore it is impossible for any vapors or dust to be generated when using PV modules. The main competition for crystalline silicon solar cells comes from a variety of thin film solar cells. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B9780128114797000105, URL: https://www.sciencedirect.com/science/article/pii/B9780128196106000028, URL: https://www.sciencedirect.com/science/article/pii/B9780128040041000099, URL: https://www.sciencedirect.com/science/article/pii/B9780128133514000468, URL: https://www.sciencedirect.com/science/article/pii/B9780124095489100922, URL: https://www.sciencedirect.com/science/article/pii/B9780128029534000020, URL: https://www.sciencedirect.com/science/article/pii/B9780128099216000355, URL: https://www.sciencedirect.com/science/article/pii/B978012811479700018X, URL: https://www.sciencedirect.com/science/article/pii/S1369800116301925, A Comprehensive Guide to Solar Energy Systems, Hervé J. Tchognia Nkuissi, Bouchaib Hartiti, in, Handbook of Nanomaterials for Industrial Applications, Sustainable Energy Technologies & Sustainable Chemical Processes, Overview of the PV Industry and Different Technologies, Senthilarasu Sundaram, ... Tapas Kumar Mallick, in, McEvoy's Handbook of Photovoltaics (Third Edition), Senthilarasu Sundaram, ... Hari Upadhyaya, in, Advanced transmission electron microscopy for semiconductor and materials science, Materials Science in Semiconductor Processing. 44.17 shows the top view SEM image of the CZTS thin film showing well-defined crystallites with small grain sizes of an average less than 0.5 µm, and the cross-sectional SEM view of CZTS layer deposited on Mo-coated SLG substrate showing also the regularly shaped and dense crystallites formed on the top of the Mo layer. �ꇆ��n���Q�t�}MA�0�al������S�x ��k�&�^���>�0|>_�'��,�G! It was found that the electroplated precursors exhibited two different reaction paths to form the Cu2SnS3 phase, depending on the metals ratios in the as-deposited films. • Zincblend structure • Direct energy gap 1.44 eV • Can be growth both p-type (VCd acceptors) or n-type (Cd i donors) • me = 0.1 m0 • µe = 1100 cm2/Vs in single crystals • Difficult extrinsic doping • ηth = 31% Source: Wikipedia. the open circuit voltage (Voc) of CdTe NC solar cells has stagnated below 0.7 V, which is significantly lower than most CdTe thin film solar cells fabricated by vacuum technology (around 0.8 V~0.9 V). springerlink.com May 2011 . Chen Li, ... Stephen J. Pennycook, in Materials Science in Semiconductor Processing, 2017. Integer Text internal endobj This may lead to secondary phase formation and may limit this technique to produce CZTS single phase. /Parent 5 0 R /Last 14 0 R external internal EPIR Technologies Bolingbrook, Illinois . Michael Carmody and Angelo Gilmore . springer.com Table 2.4. internal There are several thin film semiconductors that have been developed for solar cells. The total typical thickness of the p (25 nm)-i (500 nm)-n (30 nm) stack is within 1 micron and thus cannot absorb all the incident photons causing significant transmission losses. /rgid (PB:277928282_AS:241661968121856@1434628111146) The final zinc layer was deposited on the tin layer by Hydrion buffer using zinc chloride buffered to pH 3. e main stability issue for CdTe solar cells is the non-ohmic back contact and stability improvements have focused primarily on nding stable contacts without sacri cing e ciency []. uuid:0bff6cc0-edd6-442c-878b-06b189286d90 For this Final Report, highlights of the first two Phases will be provided and then detail will be given on the last year and a half of Phase III. SourceModified TCO layers are having prerequisite with an electron affinity below 4.5 eV to form an ohmic contact. 13 0 obj This structure achieved by rotating 90o in the base line structure that suggests high efficiency due to the high current density. Text >> By varying the amounts of copper, indium, and gallium, the bandgap of this material can be changed, and this can be used to tailor the thin film for a specific application. The solar cell fabricated using CZTS layer prepared via the electrodeposition route showed a VOC of 295 mV, a JSC of 8.7 mA/cm2, a FF of 32%, and an efficiency of 0.8% PCE [66]. internal Text Today, CIGS solar cells employ either ITO or, more frequently, RF-sputtered Al-doped ZnO. Theoretical efficiency versus energy bandgap of photovoltaic device. << A name object indicating whether the document has been modified to include trapping information /Info (sRGB IEC61966-2.1) /Length 2574 CdTe is a group II–VI compound semiconductor, and one of those whose electrical conductivity can be controlled between n-type and p-type. H���yTSw�oɞ����c [���5la�QIBH�ADED���2�mtFOE�.�c��}���0��8�׎�8G�Ng�����9�w���߽��� �'����0 �֠�J��b� If used as a dc:identifier, the URI form should be captured, and the bare identifier should also be captured using prism:doi. %���� ..... 94 . This electrolyte has a high conductivity and a good potential window of 2.5 V (−1.25 to +1.25 V) required for electrochemical applications. << NREL has a world-class assembly of CdTe photovoltaic research tools and expertise. http://ns.adobe.com/pdf/1.3/ NOTE: PRISM recommends against the use of the #other value allowed in the PRISM Platform controlled vocabulary. The CZTS films had a single-phase CZTS and were Zn-rich and S-poor. effects of ITO layers of various thicknesses on the performance of CdS/CdTe solar cells are also studied. In this paper, results of studies on the e ect of Cu doping on the low-temperature front side PL of stream They sequentially deposited metal layers of Cu, Sn, and Zn on Mo-coated SLG substrates at room temperature without stirring. They suggested that the use of an RDE can control the ion flux to the surface deposition and can therefore yield uniform films in thickness as well as in composition [124]. Date when document was last modified Comparing the rate of increase in perovskite solar cell efficiencies with the other thin-film PV technologies [19]. [1] A typical structure of CdTe solar cell can be glass superstrate/ TCO layer/ HRT Finally, the large area solar cell has a backing applied to create a module. Text Typically this will be used to provide the name of the magazine an article appeared in as metadata for the article, along with information such as the article title, the publisher, volume, number, and cover date. The CdTe solar cell has a similar structure. Schematic presentation of CdTe/CdS solar cell in “superstrate” configuration showing different layers and their nomenclature. The II-IV semiconductor compound, CdTe, has suitable electrical and optical properties as photovoltaic and high-energy radiation sensor material. The intrinsic (i) form of a-Si thin film can be doped as p-type or n-type to form a p-n junction, however, initial p-n junction device trials could not result in a solar cell action. /CrossmarkDomainExclusive (true) Then a layer of p-type CdTe is added. /Dest (Title) /PageLabels 7 0 R CrossmarkDomainExclusive 2015-05-20T12:39:25+05:30 /Subtype /Type1 Sputtering [] . Schurr et al. http://ns.adobe.com/pdfx/1.3/ In general the hierarchy of controls includes engineering controls, personal protective equipment, and work practices. /ModDate (D:20150520123958+05'30') So far, the highest efficiencies have been achieved in “superstrate” configuration for CdTe. Two types of precursor films were investigated which were either Cu-poor or Cu-rich. First Solar Inc. (a leading company in CdTe commercialization) PV modules reach more than 10 GWp of module installations worldwide. A variant of CIGS is copper indium diselenide. springerlink.com Solar Frontier (Japan) leads the production on CIS technology with annual production capacity over 1 GW and has plans to enter BIPV market with the use of aluminium in place of glass to reduce the weight of the modules. It is quite notable that even though important dissimilarities exist, the performances attained are independent to processing illustrating the versatility of CdTe and its superior prospects in the PV technologies. DocumentID /Kids [17 0 R 18 0 R 19 0 R 20 0 R 21 0 R 22 0 R 23 0 R] In contrast, silicon is one of the most abundant elements on the planet. DOI Electrochemical deposition is an attractive approach that is low cost and scalable to industrial levels, developed as an alternative to vacuum sputtering [66]. /Count 7 The aggregation type specifies the unit of aggregation for a content collection. The bandgap of CdTe directly influences the quantum efficiency of CdTe solar cells as shown in Fig. 4) The lower carrier lifetime in CdTe is considered to be responsible for the huge V OC deficit. doi:10.1007/s11664-015-3829-y No oxide impurities were found in films, contrary to those electrodeposited from aqueous solutions. The downside of this technology is the processing of the absorber at relatively higher temperatures >450°C. /BaseFont /Helvetica /Encoding << It is also now purported to be the lowest cost per watt technology, have the shortest energy payback time and be the least carbon intensive in production. amd /CreationDate (D:20150520123853+05'30') Figure 44.17. internal endobj endobj The first synthesis of CZTS using electrochemical deposition was done by Scragg et al. CdTe Solar Cells November 19, 2009 — January 31, 2011 . A range of the deposition parameters is included in Table 1. When the thickness of the ITO window layer is 325 nm, V oc = 0.82 V, J sc = 17 mA/cm2, and FF = 57.4%, the highest power conversion efficiency (PCE) is 8.6%. Indium is also available in limited quantities via the refining of a variety of metals such as zinc, copper, iron, and lead, and is in demand for liquid crystal displays and a variety of coatings. internal /quoteright /quotesinglbase /trademark /fi /fl /Lslash /OE /Scaron /Ydieresis /Zcaron All the CdS/CdTe solar cells were … Journal of Materials Chemistry C 2015 , 3 (17) , 4227-4234. /Lang (EN) >> Fig. Area and personal monitoring would provide information on the type and extent of employees’ exposure, assist in identifying potential sources of exposure, and gather data on the effectiveness of the controls. Device efficiencies on the lab scale have now exceed 22% [3] and modules have reached 18.6%, in excess of multicrystalline silicon modules (Fig. Text /Font << Text url 8 0 obj Panasonic manufactured a cell of “practical size” (101 cm2) with an efficiency of 26.7% [7]. true The short circuit current was reached up to the value of 37.6 ± 0.8 mA/cm2 from 20.3 ± 0.6 mA/cm2, as shown in Fig. Text >> publicationName The as-electroplated samples were then washed in milliQ water and dried under nitrogen. Amorphous silicon is a form of silicon with no crystal structure that is produced using thin film techniques. A cross section of a CdTe solar cell is shown in Fig. 2.7 [22]. The structure of CdTe solar cell is similar in structure as above. /Encoding 10 0 R Cadmium telluride (CdTe) solar cells have quietly established themselves as a mass market PV technology. MajorVersionDate The low cell efficiency was attributed to high series resistance and high shunt conductance which strongly affected mainly the VOC and FF values. /Type /Metadata Lacking detailed assessments for individual compounds, OSHA considers all cadmium compounds to be toxic, and, as a general guidance, all facilities working with any such compounds should control the indoors concentrations of CdTe dust or fumes to below the Permissible Exposure Level-Time Weighted Average (PEL-TWA) concentration of 0.005 mg/m3.