Environmentally Friendly Perovskite‐Based Photovoltaics and Luminescence: Lead Less or Lead Free

Lead‐based metal halide perovskite materials have been rapidly developed for light‐emitting diodes, solar cells, and photodetectors owing to their excellent optoelectronic properties. Nevertheless, the presence of lead in these materials raises critical concerns regarding their environmental impact and potential toxicity, hindering their commercial development. In response to these concerns, researchers have devoted considerable effort toward the development of environmentally friendly perovskites. In this review, the theoretical evolution path and characteristics of lead‐substituted perovskites are first emphasized, as they contribute to the development of high‐performance lead‐free halide perovskites. Additionally, the current investigation of lead‐less and lead‐free perovskites including synthesis, optoelectronic properties, and applications is systematic summarized. Notably, the positive effects of both lead‐less and lead‐free perovskites on structure, optoelectronic properties, and associated devices in comparison to their lead‐based counterpart are emphasized. Finally, potential opportunities and challenges for future research into environmentally friendly perovskites and their applications are identified.