Harnessing Pb–S Interactions for Long‐Term Water Stability in Cesium Lead Halide Perovskite Nanocrystals

Abstract

AbstractLead halide perovskite nanocrystals (LHP NCs) have garnered attention as promising light‐harvesting materials for optoelectronics and photovoltaic devices, attributed to their impressive optoelectronic properties. However, their susceptibility to moisture‐induced degradation has hindered their practical applications. Despite various encapsulation strategies, challenges persist in maintaining their stability and optoelectronic performance simultaneously. Here, a ligand exchange approach is proposed using (11‐mercaptoundecyl)‐N,N,N‐trimethylammonium bromide (MUTAB) to enhance the stability and dispersibility of CsPbBr3 (CPB) NCs in aqueous environments. MUTAB enables effective surface passivation of the CPB NCs via robust Pb–S interactions at the S‐terminal while concurrently directing water molecules through the unbound cationic N‐terminal or vice versa, ensuring water dispersibility and stability. Spectroscopic analysis confirms retained structural and optical integrity post‐ligand exchange. Crucially, MUTAB‐bound CPB NCs exhibit sustained charge transfer properties, demonstrated by aqueous colloidal oxidation reactions. This ligand exchange strategy offers a promising pathway for advancing LHP NCs toward practical optoelectronic and photocatalytic applications.