Vapor‐Phase Deposition of CsPbBr 3 Shells on Iodide‐Rich Perovskite Cores in SiO 2 for Efficient and Robust Red Emission
Chao Fan, Luyue Niu, Xudong Cheng, Haoxin Wang, Mengda He, Yichen Qu, Mengyuan Zhang, Baolong Jing, Jiayuan Wei, Xuejing Wang, Daibin Kuang, Liang LiABSTRACT
While high‐temperature solid‐phase confined synthesis has established itself as a viable approach for producing ultra‐stable halide perovskite nanocrystals (NCs), the photoluminescence quantum yield (PLQY) of the resulting red‐emitting NCs, whether pure‐iodide or mixed‐halide, remains unsatisfactory. In this work, we introduce a high‐temperature vapor‐phase deposition for the controlled synthesis of CsPbI 3 /CsPbBr 3 and CsPb(Br/I) 3 /CsPbBr 3 heterostructure NCs encapsulated within a robust SiO 2 matrix. This method spatially separates the CsPbBr 3 shell precursor from the preformed iodine‐rich core in the vapor phase, effectively suppressing undesirable halide diffusion during high‐temperature processing at 700°C. By leveraging the strong Br─Cs/Pb interactions, the CsPbBr 3 vapor promotes preferential interfacial deposition on CsPbI 3 or CsPb(Br/I) 3 cores. The resulting NCs display highly efficient red emission, achieving a PLQY as high as 85%. Furthermore, benefiting from the dual protection of the SiO 2 matrix and the heterostructure, these red‐emitting materials exhibit outstanding environmental stability while retaining their high performance.