Comparative Numerical Analysis of Lead-Free Perovskite Solar Cells Using SCAPS-1D

A comprehensive numerical study of lead-free perovskite solar cells was conducted using the SCAPS-1D simulation framework with the device architecture ITO/SnO2/Perovskites/NiOx/Au. The work investigates the replacement of the central Pb cation with Sn, Ge, and Bi, followed by absorber-layer thickness optimization to enhance device performance. The impact of systematic Pb substitution on key photovoltaic parameters was first evaluated. Among the candidates, FASnI3-based devices exhibited the most promising performance, achieving a power conversion efficiency (PCE) of 26.48%, with a short-circuit current density (Jsc) of 19.31 mAcm^-2, an open -circuit voltage (Voc) of 1.57 V, and a fill factor (FF) of 87.29%. Further optimization of absorber thickness revealed an optimal value of 1600 nm, yielding an enhanced PCE of 27.15%. These results highlight the strong potential of Pb-free perovskites for next-generation eco-friendly photovoltaic technologies.