Recent developments of lead-free halide-perovskite Cs3Cu2X5 (X = Cl, Br, I): Synthesis, modifications, and applications

In recent years, metal halide perovskites have attracted extensive attention due to their excellent properties in fields of solar cells, light-emitting diodes, high-energy ray detectors, and medical imaging devices, etc. At present, lead halide perovskites are the most widely used one in photoelectric devices among all kinds of perovskites. However, the toxicity of lead halide perovskites to humans and the environment and their poor stability to light, heat, and humidity hinder their application and commercialization. Therefore, low-toxic and environmentally benign lead-free perovskites are continuously researched and developed to replace lead halide perovskites. Due to the advantages of lead-free, cheap, and high stability for Cu+, Cs3Cu2X5 (X = Cl, Br, I) has been broadly studied in the past five years, showing excellent properties as Cu-based perovskites. In this review, a comprehensive overview of Cs3Cu2X5 are reported. Here, the synthesis, doping, and encapsulation methods, and luminescence mechanisms in Cs3Cu2X5 are discussed and their exciting potential applications are highlighted. The current challenges and futural prospects of Cs3Cu2X5 in multi-purpose potential applications are summarized and proposed.