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.