Comprehensive Numerical Analysis of High Efficient Lead-Free CH3NH3SnI3 based Perovskite Solar Cell

Perovskite solar cells (PSCs) have been among the most promising highly efficient next-generation photovoltaic devices with bandgap tunability and low production cost. However, lead toxicity, architectural limitations, along with defect-induced recombination hinder their commercialization. To address these limitations, this study investigates CH3NH3SnI3 as a non-toxic absorber in an FTO/WSe2/CH3NH3SnI3/NiO/Au device architecture. Through systematic numerical simulations using SCAPS-1D, the key design parameters—layer thicknesses, doping densities and defect concentrations—are carefully optimized. The resulting device structure shows a high power conversion efficiency of 34.74%, with Voc of 1.1084 V, Jsc of 36.7788 mA/cm2, fill factor of 85.22% and peak quantum efficiency of 99.95% at 390 nm wavelength under AM 1.5G illumination. Sensitivity analysis reveals that both bulk (Nt>1014 cm-3) and interface (Nint>1017 cm-3) defects drastically degrade the performance, particularly at the CH3NH3SnI3/WSe2 interface. These findings have significant implications for the design principles required for high-efficiency lead-free PSCs.