Elsevier, Solar Energy Materials and Solar Cells, (134), p. 340-345
DOI: 10.1016/j.solmat.2014.10.041
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In this paper, we examine photoluminescence spectra (PL) of Cu2ZnSnSe4/CdS/ZnO solar cells, based on an absorber layer fabricated by selenization of sputtered Cu, Zn, Sn multilayers, via temperature-dependent and illumination power-dependent measurements. We observe anomalous emission behavior: the PL peak initially decreases with increasing temperature (red shift) in the temperature range 10-60 K, followed by a blue shift at higher temperature in the range 60-180 K. A recombination model is proposed that is able to explain both temperature dependent PL as well as power-dependent PL The important aspect of the proposed model is taking into account the presence of strong potential fluctuations in the absorber layer, which can also contribute to the low V-oc values generally observed in Cu2ZnSnSe4, based solar cells. (C) 2014 Elsevier B.V. All rights reserved. ; Cu2ZnSnSe4/CdS/ZnO; solar cells; photoluminescence spectra (PL); recombination; potential fluctuations; donor–acceptor pairs DAP; quasi-donor–acceptor pairs Q-DAP