Opportunities and Challenges of Lead-Free Perovskite Optoelectronic Devices

Organic–inorganic hybrid halide lead-based perovskites have attracted tremendous attention as novel active materials in solar cells due to their superior optical and electrical properties, with power conversion efficiencies (PCEs) reaching 23.7%. However, the toxicity of Pb-based perovskite materials still hinders their commercialization. Therefore, finding alternative ions to lead in perovskite materials to form environmentally friendly materials is highly desirable. In this review, promising candidates as lead substitutes are presented and discussed as applied to perovskite solar cells (PSCs), light-emitting diodes (LEDs), and photodetectors. The fabrication processes and methods that could improve the stability of lead-free perovskite materials are also included. Our findings reveal the spectacular performance of lead-free perovskites. Moreover, the present status and future perspectives are also discussed.