Improvement of Chemical Stability of Perovskite Nanocrystals as a Photoelectrochemical Catalyst for Hydrogen Evolution Reaction

Abstract

Recent advances in the synthesis and processing of perovskite materials have led to significant improvements in their stability under harsh conditions, making them increasingly attractive for use as photo and photoelectrochemical catalysts. In particular, core-shell structured perovskite nanocrystals have greatly enhanced chemical stability, enabling their use in aqueous environments; however, their low conductivity remains a challenge. To address this issue, this study developed two-time cross-linkable core-shell perovskite nanocrystals using two types of silanes, resulting in excellent chemical stability and high conductivity. The first cross-linking reaction was spontaneously initiated in the solution state, forming an ultrathin Si-O-Si amorphous matrix on the surface of the perovskite nanocrystals. The second cross-linking reaction was intentionally induced in the film state by exposing it to UV light. The resulting cross-linked perovskite/SiO2 nanocrystal films exhibited a high packing density, and among four different dopants, the Ag-doped film demonstrated the lowest onset potential for HER in a 0.5 M H2SO4 aqueous solution due to effective band modulation. These findings suggest that the two-time cross-linking approach can significantly enhance the performance of perovskite nanocrystals in photoelectrochemical applications.