Metal Halide Perovskite Alloy: Fundamental, Optoelectronic Properties and Applications

Metal halide perovskites (MHPs) have demonstrated great advances for photovoltaic and optoelectronic applications. However, owing to the presence of the synergy from lattice strain, defects of MHPs, and environment, MHPs suffer from phase transitions and degradation, resulting in the restriction of their practical applications and further commercialization. Multiple metal elements can coexist in MHPs to form alloys due to the high tolerance of lattice and the composition replaceability, which provides a novel strategy for improvement of performance and stability. In this review, the recent advances of alloy engineering of MHPs, focusing on the cation and the metal ion (A- and B-site) alloy strategies, are reviewed. The alloy effects on the crystalline structure, optoelectronic properties, ferroelectricity, carrier dynamics, and stability of perovskites are interpreted. Finally, the prospect of this study is the challenges in the MHPs alloy engineering.