All-inorganic perovskite photovoltaics for power conversion efficiency of 31%

The lead-free perovskite halides emerge as the great alternative for highly efficient and environment friendly photovoltaics due to the inherent optoelectronic properties. In this paper, the numerical study of all-inorganic regular n-i-p structured perovskite photovoltaics using solar cells capacitance simulator (SCAPS-1D) has been performed. The optimised device structure using rGO provided best performance compared to the other hole transport layers (HTLs) like CuI, CuSCN, Cu2O, NiO, WSe2, MoO3 with CsSnI3 as an active material and TiO2 as electron transport layer (ETL). Furthermore, WS2 as an ETL compared to TiO2, Li-TiO2, ZnO, Al-ZnO, etc. provided the best performance with rGO as HTL and CsSnI3 as active material. Therefore, the optimized solar cell structure (FTO/WS2/CsSnI3/rGO/Pt) showed best photovoltaic performance with power conversion efficiency (PCE) of 31%, fill factor (FF) of 88.48%, open circuit voltage (VOC) of 1.15 V, and short circuit current density (JSC) of 30.47 mA/cm2, respectively. Consequently, the effect of variation of temperature, thickness, defect density, doping density of active layer and variation of illumination intensity on the photovoltaic performance of the optimised device are also analysed. Furthermore, this study is also focused on the analysis of photovoltaic parameters for the optimized structure using concept of ideality factor associated with the illumination intensity. Therefore, this analysis suggests a route for further development of all-inorganic, lead-free perovskite photovoltaics experimentally with improved photovoltaic performance.