Photovoltaic properties of narrow-bandgap Cu2SnS3 (CTS) are studied for the first time by employing a superstrate solar cell structure of fluorine-doped tin oxide (FTO) glass/TiO2/ln(2)S(3)/CTS/Mo. The structural, optical, and electronic characteristics of the CTS make it great potential as bottom cell absorber material for low-cost thin film tandem solar cell application. Furthermore, by inserting a thin low temperature deposited ln(2)S(3) layer between the ln(2)S(3) buffer layer and the CTS absorber layer, an enhancement in the performance of the solar cell can be achieved, leading to about 75% improvement (eta = 1.92%) over the unmodified device (eta = 1.10%). (C) 2012 Elsevier Inc. All rights reserved.