Copper-based perovskites and perovskite-like halides: A review from the perspective of molecular level

The toxicity of lead and instability are crucial factors hindering the commercialization of lead-based halide perovskite materials. In recent years, copper has been considered as one of the promising alternatives to lead in perovskites due to its abundance, environmental friendliness, and unique electronic structure. A bunch of new copper-based perovskite-like materials have been synthesized and their physical properties and chemical stabilities have been explored. However, there is still a lack of a comprehensive and systematic overview regarding copper-based perovskites and perovskite-like halides from the molecular level perspective. Therefore, focusing on the molecular structure, this review provides a summary of the crystal structures, electronic properties, and application principles of copper-based all-inorganic and organic-inorganic hybrid perovskites and perovskite-like halides. Furthermore, we have discussed the limitations of copper-based perovskites and perovskite-like halides, as well as provided our outlook on their future development directions.