There is an increasing interest in lead-free perovskite materials for solar cell applications, attributed to their exceptional performance and non-toxic properties. This research presents a comprehensive examination of the photovoltaic performance of \(\hbox {FASnI}_3\) -based perovskite solar cell configurations utilizing SCAPS-1D. The architectural design of FTO/ \(\hbox {WO}_3\) / \(\hbox {FASnI}_3\) /CuI/Au demonstrates significant reliability, accomplished by meticulous optimization of parameters including thicknesses, acceptor densities, defect densities, interfacial defect densities, and both series and shunt resistances across all layers. The simulations yielded notable results, demonstrating a short-circuit current density of 31.82 mA/ \(\hbox {cm}^2\) , an open-circuit voltage of 1.14 V, a fill factor of 79.74%, and a power conversion efficiency of 28.90%. Furthermore, we employed impedance spectroscopy, a method that offers significant insights for the evaluation and analysis of perovskite solar cells. The research utilized an extensive range of frequency spanning \(10^{-2}\) – \(10^{7}\) Hz to examine the performance and diffusion processes associated with PSC. Furthermore, the equivalent circuit for the solar cell utilizing ZSimpWin software have been developed, resulting in accurate alignment and minimal discrepancies. This combination suggests the possibility of creating environmentally sustainable perovskite solar cells, which could aid in the advancement of thin and efficient devices to address future challenges in renewable energy applications.
