Lead vs. tin in the preparation of metal halide perovskites: is this the real fight for the future of solar energy?

Abstract

Metal halide perovskites (MHPs) have gained attention as a viable alternative to crystalline silicon solar cells, offering comparable power conversion efficiencies exceeding 26%. However, their large-scale adoption remains limited by several challenges, most notably, the reliance on toxic post-transition metals like lead. While efforts have been made to replace lead with less hazardous metals such as tin, a comprehensive evaluation of the environmental trade-offs has often been overlooked. This study presents, for the first time, a quantitative comparison of the environmental and human health impacts associated with lead and tin precursors in the fabrication of two benchmark perovskite active layers: MAPbI₃ and MASnI₃. The results show that tin accounts for 27.6% of the total manufacturing impact, compared to only 18.8% for lead. The endpoint single score analysis further highlights that tin is 1.6–1.8 times more impactful than lead. Based on the LCA data, a tin-based device would at least require a PCE of ca. 42% to match the environmental and PCE performance of its lead-based counterpart.