Recent development in metal halide perovskites synthesis to improve their charge-carrier mobility and photocatalytic efficiency

Over the past decade, all-inorganic metal halide perovskites (MHPs, CsPbX3: X = Cl, Br, I) have been widely investigated as promising materials for optoelectronic devices such as solar cells and light-emitting diodes. MHPs are defect-tolerant, which allows tuning of their bandgap without altering their photophysical properties. From a fundamental point of view, MHPs are excellent candidates for photocatalytic reactions due to their light-harvesting capability, high photogenerated charge-carrier mobility, long diffusion lengths, and tunable bandgap energy. In this review, we provide an overview of various MHP engineering strategies (e.g., surface, morphological, and structural modifications, heterojunction coupling, and encapsulation) which are directly linked to the charge-carrier mobility and lifetimes, and then to the photo-catalytic efficiency. Specifically, we outline different synthetic approaches resulting in surface and morphological modifications, anion/cation substitution, metallic doping, coupling, and encapsulation that tremendously influence MHPs' stability, optical properties, and charge-carrier dynamics at variable time scales (from fs to µs). We also provide an in-depth evaluation of the MHPs for variable photoredox reactions, discussing how the optical and electronic properties help to improve their stability and efficiency.