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Transparent Back Contacts for CdTe Solar Cells: Criteria and Investigation of Oxide Materials
R.S. Hall, D.A. Lamb, A. Pockett, S.K. Thomas, M.J. Carnie, S.J.C. Irvine
Perovskites and Other Non-Silicon Materials, MJs and Tandems
Subtopic: CI(G)S, CdTe and Related Thin Films
Event: 37th European Photovoltaic Solar Energy Conference and Exhibition
Session: 3CO.8.2
ISBN: 3-936338-73-6
0,00 EUR
Document(s): presentation


CdTe is the leading commercial thin film solar cell technology with record cell efficiency of over 22%, still well below the Shockley-Queisser limit. There is an emerging consensus that 25% cell efficiency can be achieved1. This requires firstly the front contact recombination to be reduced without affecting the short-circuit current, and secondly back interface recombination must also be reduced. One means of increasing module efficiency is to allow additional radiation to enter the absorber through the back contact, i.e. a bifacial cell; another is to use a tandem cell with a CdTe top cell and a lower band gap bottom cell. A third possibility is to use transmitted infrared radiation in a heat engine. Ultimately, each of these applications might require a different optimization of the CdTe solar cell stack. This work discusses the criteria required for transparent back contacts, both optical and electrical. We seek to identify and develop potential back contact materials for exploitation either in bifacial or tandem cells. However, in many cases a fundamental study of the back contact material interface with CdTe is necessary.