Charge Transfer Boosting Moisture Resistance of Seminude Perovskite Nanocrystals via Hierarchical Alumina Modulation.

Boosting the stability improvement of cesium lead halide (CsPbX) perovskite nanocrystals (NCs) remains a serious challenge. In this work, CsPbX NCs are effectively anchored on a hierarchical (-) alumina (AlO) substrate to form seminude CsPbX@-AlO composites, which can emit strong green light even after being stored in water for 30 days, in sharp contrast to the pure CsPbBr NCs. Other oxides, such as TiO, ZnO, and SiO, have no boosting effect on the moisture resistance of perovskite NCs. Subsequent density functional theory calculations reveal a significant charge transfer and strong Coulomb attraction between CsPbBr and AlO. The substantial charge transfer via alumina substrate modulation not only can enhance the internal stability of CsPbBr but also can cause CsPbBr to be insensitive to water adsorption. These findings are expected to deepen our understanding of improving the stability of CsPbBr NCs and shed light on the design of novel perovskite composites for long-term stable optoelectronic devices.