LAUSR

Abstract Incorporation of SnS as a blocking layer at the interface of TiO2 and CH3NH3PbI3(MAPbI3) perovskite has been investigated. With respect to the control, the inclusion of a 3 nm SnS layer via thermal evaporation leads to an improved power conversion efficiency as well as stability, under similar storage conditions. The highest power conversion efficiency of approx. 13.6% is achieved for the champion cell (average 12%) and stability study over the period of 4 weeks revealed the retention of approximately 85% of its initial efficiency (average 83%). The surface photovoltage spectroscopy (SPV) measurements confirmed that the improvement in the photovoltaic performance is due to the lower photogenerated electron lifetime exhibited by devices with the SnS blocking layer which in turn is attributed to the reduction of trap states at the TiO2-perovskite interface, decreasing the interfacial charge recombination. Electrical impedance spectroscopy (EIS) and photoluminescence (PL) spectroscopy, additionally endorse the reduction of traps and recombination centers.