Comparative Analysis Using the SCAPS-1D Software on the Stability and Toxcity of the Perovskites FAPbI3, and FASnI3

Abstract

Hybrid organometallic perovskites such as FAPbI₃ (formamidinium lead iodide) and FASnI3 (formamidinium tin iodide) are recognized as promising materials for the next generation of high-efficiency solar cells. FAPbI₃ is particularly valued for its stability and excellent optoelectronic properties. However, the toxicity of lead and the resulting environmental concerns drive the search for alternatives like FASnI₃, where tin, a less toxic and more abundant element, replaces lead, which is the objective of this study. The lead-free structure simulated using SCAPS-1D software is as follows: FTO/TiO₂/FASnI₃/Spiro-OMeTAD/Ag. The research presented here shows that optimizing several parameters can achieve a power conversion efficiency (PCE) of 22.49%. We opted for TiO₂ as the ETL due to its wide bandgap (~3.2 eV for the anatase phase), which effectively blocks holes and prevents their recombination with electrons, thus promoting better charge separation. Moreover, the favorable energy level alignment of TiO₂ with the perovskites facilitates the transfer of electrons to the silver (Ag) electrode. For the HTL, we chose Spiro-OMeTAD, whose valence band level is well aligned with that of the perovskites, making it easier to extract holes to the upper silver electrode. Using the SCAPS-1D simulator, we then compared the electrical and optical properties of the devices, focusing on key parameters such as short-circuit current density (Jsc), open-circuit voltage (Voc), fill factor (FF), and power conversion efficiency (PCE). The best results obtained after optimizing the aforementioned parameters are Jsc of 30.65 mA/cm2 , Voc of 0.8469 V, FF of 86.63%, and PCE of 22.49%. Additionally, the structure studied in this article could be a good candidate for future research on lead-free perovskite solar cells.