Decoding device physics in lead-free CsSnBr₃ perovskite solar cells: The interplay of material quality and electrical dynamics

Abstract Renewable energy has emerged as one of the most considerable and sustainable alternatives to conventional fossil fuels, with solar photovoltaics (PV) playing a leading role in this transition. Among the different PV technologies, perovskite solar cells (PSCs) have gained remarkable attention due to their excellent optoelectronic properties, tunable bandgap, and low fabrication cost. However, stability and toxicity issues associated with lead-based perovskites have encouraged researchers to explore lead-free alternatives. In this work, we present a simulation-based investigation of a tin-based double perovskite solar cell with the structure FTO/CdS/CsSnBr₃/MoO₃/C using the SCAPS-1D environment. A comprehensive analysis was performed by systematically varying critical device parameters, including absorber thickness, donor and acceptor concentrations, ETL and HTL thicknesses, temperature, back contact work function, and both shunt and series resistances. The optimized device exhibited a remarkable power conversion efficiency (PCE) of 23.87%, with an open-circuit voltage (Voc) of 1.44 V, a short-circuit current density (Jsc) of 19.67 mA/cm², and a fill factor (FF) of 83.97%. Furthermore, a comparison with various reported studies revealed that our proposed device demonstrates strong agreement with existing literature, validating the reliability of both the simulation and experimental results. Overall, the findings highlight the significant potential of CsSnBr₃-based lead-free double PSCs for future commercialization.