By a News Reporter-Staff News Editor at Science Letter -- A new study on Science is now available. According to news reporting originating in Dubendorf, Switzerland, by NewsRx journalists, research stated, "Thin-film photovoltaic devices based on chalcopyrite Cu(In,Ga)Se-2 (CIGS) absorber layers show excellent light-to-power conversion efficiencies exceeding 20% (refs 1,2). This high performance level requires a small amount of alkaline metals incorporated into the CIGS layer, naturally provided by soda lime glass substrates used for processing of champion devices(3)."
The news reporters obtained a quote from the research from Swiss Federal Laboratories for Materials Science and Technology (EMPA), "The use of flexible substrates requires distinct incorporation of the alkaline metals, and so far mainly Na was believed to be the most favourable element, whereas other alkaline metals have resulted in significantly inferior device performance(4,5). Here we present a new sequential post-deposition treatment of the CIGS layer with sodium and potassium fluoride that enables fabrication of flexible photovoltaic devices with a remarkable conversion efficiency due to modified interface properties and mitigation of optical losses in the CdS buffer layer. The described treatment leads to a significant depletion of Cu and Ga concentrations in the CIGS near-surface region and enables a significant thickness reduction of the CdS buffer layer without the commonly observed losses in photovoltaic parameters(6)."
According to the news reporters, the research concluded: "Ion exchange processes, well known in other research areas(7-13), are proposed as underlying mechanisms responsible for the changes in chemical composition of the deposited CIGS layer and interface properties of the heterojunction."
For more information on this research see: Potassium-induced surface modification of Cu(In,Ga)Se-2 thin films for high-efficiency solar cells. Nature Materials, 2013;12(12):1107-1111. Nature Materials can be contacted at: Nature Publishing Group, Macmillan Building, 4 Crinan St, London N1 9XW, England. (Nature Publishing Group - www.nature.com/; Nature Materials - www.nature.com/nmat/)
Our news correspondents report that additional information may be obtained by contacting A. Chirila, Empa, Swiss Fed Labs Mat Sci & Technol, Center Electron Microscopy, CH-8600 Dubendorf, Switzerland. Additional authors for this research include P. Reinhard, F. Pianezzi, P. Bloesch, A.R. Uhl, C. Fella, L. Kranz, D. Keller, C. Gretener, H. Hagendorfer, D. Jaeger, R. Erni, S. Nishiwaki, S. Buecheler and A.N. Tiwari (see also Science).
Keywords for this news article include: Europe, Science, Dubendorf, Treatment, Switzerland, Electronics, Photovoltaic
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