Structure-Dependent Interfacial Electronic Behavior in CsPbBr ₃ /SiO ₂ Heterostructures: Theoretical and Experimental Insights

Perovskite nanocrystals are promising for optoelectronics, yet environmental degradation under humidity, light, and thermal stress hinders commercialization. Although silica (SiO 2 ) encapsulation improves stability, the interfacial adhesion and charge redistribution mechanisms at the perovskite/SiO 2 heterostructure remain unclear. Here, we combine density functional theory (DFT) calculations and experimental characterization to investigate the CsPbBr 3 /SiO 2 heterostructure, with the CsSnBr 3 /SiO 2 system included as a computational reference. The PbBr-OSi interface exhibits the highest binding energy, which induces significant charge redistribution at the interface. Charge density difference and Bader analyses further reveal directional electron transfer from the perovskite to SiO 2, accompanied by enhanced visible-UV optical absorption. X-ray diffraction (XRD) and elemental mapping confirm the formation of a well-defined CsPbBr 3 /SiO 2 heterostructure, while X-ray photoelectron spectroscopy (XPS) reveals negative shifts in Si 2p and O 1s and positive shifts in Pb 4f and Br 3d, directly validating the predicted electron migration. This work establishes a structure–property relationship between atomic-scale interface structure and electronic behavior, providing guidance for the rational design of stable perovskite/SiO 2 heterostructures.