Thin-film intermediate band photovoltaics: advanced concepts for chalcopyrite solar cells

We have studied the potential of thin-film photovoltaic devices provided with an intermediate band (IB). Cu-containing chalcopyrites appear as promising candidates, with maximum theoretical efficiencies above 45% under ideal conditions. This figure has been re-evaluated by considering a number of non-idealities, like optical and current losses and non-radiative recombination that affect current chalcopyrite-based devices. Strategies for the practical implementation of IBs in chalcopyrite hosts will be discussed, including the incorporation of foreign impurities in the chalcopyrite structure at substitutional sites of the cation sublattice and the realisation of nanostructured devices. (c) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim