Efficacy of perovskite photocatalysis: challenges to overcome

Having gained prominence in the design of high-efficiency solar cells, metal halide perovskites have taken center stage in photocatalysis. Despite the demonstrations of photocatalytic activity in inducing reduction and oxidation processes through visible-light excitation, the long-term stability of CsPbBr3 and other perovskite nanocrystals and nanostructures still poses a challenge. This Perspective discusses how factors such as instability arising from labile ligands, ease of halide exchange, halide mobility under photoirradiation, chemical and morphological transformations in polar solvents, and difficulty in designing heterostructures pose major hurdles in developing halide perovskites as photocatalysts. The key examples of organic and inorganic transformations as well as interfacial charge-transfer processes discussed here present some unique features of perovskite photocatalysts and highlight the complexity in their utilization for future chemical conversion processes. Strategies to protect the perovskite surface are needed to maintain the required long-term stability in practical applications.