ASnX3—Better than Pb‐based Perovskite

Abstract Organic‐inorganic halide perovskite solar cells (PSCs) have drawn tremendous attention as their power conversion efficiency (PCE) has soared to 25.2%. Yet the most efficient halide perovskite materials all contain the toxic element lead (Pb). The search for an alternative element is a crucial research direction. Among all candidates, tin (Sn) appears to be the most promising one for its nontoxicity and physical similarity to lead (Pb). Herein, we review and summarize recent advancements in this emerging research area of Sn‐based perovskites. First, we discuss the photophysical dynamics of the Sn‐based perovskites and the relatively high efficiency of corresponding PSCs and other applications. Then, the attention is focused on the fabrication process and methods to improve the performance of Sn‐based photovoltaic devices. Despite the fact that the stabilities of the materials and related devices are far from perfect, the Sn‐based perovskites are still the best candidates with vast potential among all the Pb‐free perovskites for PSC application.