Recent promise of lead-free halide perovskites in optoelectronic applications

Organic-inorganic halide perovskites have gathered vast interest in emerging optoelectronic technologies because of their unique optical and electrical properties recently. The toxicity in these lead halide perovskites has become a stumbling roadblock that limits their wide-scale application. Therefore, developing lead-free (Pb-free) alternative perovskites without sacrificing performance and stability is highly desired in these optoelectronic devices. Here we present a comprehensive review of recent advances in Pb-free perovskites in various optoelectronic applications. A snapshot of the crystal structure and composition diversity for these Pb-free perovskites is first provided. To better grasp the innate character of these perovskites, the crystallographic, optical, and electronic properties are concisely summarized and elaborated in the second section. A systematic overview of the Pb-free perovskite optoelectronic applications of solar cells, photodetectors, light-emitting diodes, photocatalysis, and sensors is critically presented. The challenges and perspectives for the future development of Pb-free perovskite optoelectronics are outlined, which are believed to be vital for expediting the commercial implementation of these emerging technologies.