Computational Screening of Two-Dimensional Lead-Free Halide Double Perovskites for Solar Cells

Lead halide perovskites have gained attention as affordable and high-performance photovoltaic absorbers while their practical application is limited by poor structural stability and the toxic nature of the heavy metal lead. In this study, we proposed a dimensional reduction strategy to modulate the electronic structures of lead-free halide double perovskites (HDPs). Through a theoretical photovoltaic-guided material screening workflow from 392 kinds of lead-free HDP monolayers, we identified one optimal perovskite Cs₄CuBiBr₈ monolayer with intrinsic thermodynamic stabilities, suitable bandgaps, and small charge carrier effective masses as promising candidate for replacing Pb-based photovoltaic absorbers. Our work provides valuable theoretical insights for experimental research and expedites the exploration of environmentally friendly candidates for photovoltaic devices.