Tracking Carrier Dynamics in Halogen‐Mixed CsPb(Br/I)3 Quantum Dots in Glass

Abstract Halogen‐mixed CsPb(Br/I) 3 perovskite quantum dots (PeQDs) embedded glass can address the issue of stability, but suffers from low photoluminescence quantum yields (PLQYs) for the hindered in situ nucleation/growth inside the robust glass network. Uncovering the exact mechanism is highly desirable to develop high‐performance CsPb(Br/I) 3 @glass for commercial applications, but the topic remains unexplored. Here, based on femtosecond transient (fs‐TA) absorption, temperature‐dependent PL spectra, and theoretical calculations, a comprehensive understanding on heat‐treatment (HT) temperature‐induced modification of microstructures and carrier dynamics in the CsPb(Br/I) 3 @glass is build. It is evidenced that high‐temperature HT will promote more I − ions diffusion from glass matrix into CsPb(Br/I) 3 lattice, leading to the retarded hot carrier (HC) cooling, and improved exciton recombination. This is attributed to the synergistic effect of the reduced effect carrier mass, the weakened carrier‐phonon coupling, the inhibited Klemens channel, and the eliminated defect states. Revealing these underlying mechanisms will empower to exert precise control and optimize PLQY of CsPb(Br/I) 3 @glass up to near unity.