A Potential Checkmate to Lead: Bismuth in Organometal Halide Perovskites, Structure, Properties, and Applications

The remarkable optoelectronic properties and considerable performance of the organo lead‐halide perovskites (PVKs) in various optoelectronic applications grasp tremendous scientific attention. However, the existence of the toxic lead in these compounds is threatening human health and remains a major concern in the way of their commercialization. To address this issue, numerous nontoxic alternatives have been reported. Among these alternatives, bismuth‐based PVKs have emerged as a promising substitute because of similar optoelectronic properties and extended environmental stability. This work communicates briefly about the possible lead‐alternatives and explores bismuth‐based perovskites comprehensively, in terms of their structures, optoelectronic properties, and applications. A brief description of lead‐toxification is provided and the possible Pb‐alternatives from the periodic table are scrutinized. Then, the classification and crystal structures of various Bi‐based perovskites are elaborated on. Detailed optoelectronic properties of Bi‐based perovskites are also described and their optoelectronic applications are abridged. The overall photovoltaic applications along with device characteristics (i.e., V (OC), J (SC), fill factor, FF, and power conversion efficiency, PCE), fabrication method, device architecture, and operational stability are also summarized. Finally, a conclusion is drawn where a brief outlook highlights the challenges that hamper the future progress of Bi‐based optoelectronic devices and suggestions for future directions are provided.