Investigations on the effect of buffer layer on CMTS based thin film solar cell using SCAPS 1-D

Research in the field of thin film photovoltaic has been stimulated because of the low production cost and less material consumption and it has been accelerating after the exploration of chalcogenide materials viz. CIS, CIGS, CdTe and CZTS. But, toxicity of Cadmium, high cost of Indium and Gallium and plenty of barriers in improvement of efficiency in case of CZTS gave rise to research in similar and less explored chalcogenide materials and candidate material among them. Copper Manganese Tin Sulphide (CMTS) is one of the promising chalcogenide materials for development of low-cost, thin-film solar cells. However, being a new material, there are not many reports on the optimisation of device structure for this materials system. Particularly there is no systematic studies on the material-compatibility as far as the buffer layer is concerned for the CMTS based solar cell. In this work, we studied the effect of the buffer layer (CdS, Zn(O,S) and SnS2) on the performance of the CMTS based thin film solar cell device by using SCAPS 1-D simulation. We report that the device with SnS2 as a buffer layer shows comparatively high power conversion efficiency, that is 20.26%. Subsquently, the device structure of CMTS solar cell with SnS2 buffer layer was optimized for various physical parameters, viz. Thickness of the absorber and buffer layer, acceptor density of the absorber layer, donor density of the buffer (SnS2) layer, and the defect density. These results could be helpful in designing and experimentally implementing the CMTS based low-cost thin-film solar cell with Cd-free buffer layer.