In Situ Compositing CsPbBr₃ with Exfoliated Layered-Perovskite CsCa₂Ta₃O₁₀: Interfacial Interaction and Enhanced...

Cesium lead halide (CsPbX₃, X = Cl, Br, I) perovskite quantum dots (QDs) have been intriguing optoelectronic materials for applications in various devices owing to their superior electronic and optical properties. However, poor resistance to humidity and light irradiation impedes their promotion. Herein, bulk perovskite-type layered CsCa₂Ta₃O₁₀ is exfoliated into two-dimensional (2D) negatively charged Ca₂Ta₃O₁₀^- (CTO) nanosheets as seeds to in situ synthesize and composite CsPbBr₃. The as-synthesized CsPbBr₃/CTO nanocomposites possess improved green emission with apparently prolonged decay time with reference to bare CsPbBr₃ QDs. The decay time can retrieve to a normal state when the nanocomposites are treated with some water. It is found that the CTO acts as a defect to trap the bound exciton of the loaded CsPbBr₃. Protons from water can preferably replace Cs⁺ at the interface of the nanocomposites, resulting in the separation of the nanosheets and CsPbBr₃ and retrieving the decay time. X-ray photoelectron spectroscopy results also indicate the strong interaction between CsPbBr₃ and CTO with reference to the physical mixing sample of bare CsPbBr₃ QDs and CTO nanosheets. The decoration of ultrathin 2D charge-bearing oxide nanosheets on the QDs benefits significant improvements in humidity resistance and photostability performance in light-emitting diode devices. This research offers a distinct strategy to modify the surface of perovskite QDs.