Metal Halide Perovskite Nanocrystals for C–X Activation: Role of Halide Vacancies

Metal halide perovskite nanocrystals (NCs) possess immense potential in photocatalysis. However, deciphering the intricate surface chemistry that governs these catalytic processes remains a challenge. This study investigates C–X bond activation with CsPbBr3 NCs, focusing on elucidating the role of dynamic molecular domains in dictating catalytic activity. By manipulating surface interactions through ligand dynamics, we identify halide vacancies as critical sites for C–X bond activation. A systematic exploration of different ligand types reveals varying kinetics of C–X exchange, with oleyl amine-capped CsPbBr3 NCs demonstrating the highest reactivity. Temperature-dependent photoluminescence measurements corroborate these findings, highlighting the influence of ligand dynamics on surface interactions. Additionally, postsynthetic treatments, such as lead oleate modification, which leads to an increase in the density of active sites (halide vacancies), significantly enhance catalytic performance. Conversely, SOBr2 treatment, which repairs surface bromide vacancies, results in almost completely suppressed catalytic activity. So, by engineering surface environments, we demonstrate significant improvement in the catalytic performance of metal halide perovskite NCs, offering valuable insights for future development.