Lead-free rare-earth double perovskite Cs2AgIn1−γ−xBixLaγCl6 nanocrystals with highly efficient warm-white emission

Lead-free double perovskite nanocrystals (NCs), such as Cs2AgInCl6, have attracted considerable attention stable and non-toxic alternatives to lead-based perovskites. However, the low photoluminescence (PL) intensity of pristine Cs2AgInCl6 limits its practical applications. In this study, a series Cs2AgIn1−γ−xBixLaγCl6 NCs were synthesized break parity-forbidden transition modify associated optical functionalities. A broadband bright warm-white emission in visible region was achieved, with an excellent PL quantum yield 60%. The dynamic mechanism, involving ultrafast transient absorption, suggests that high-efficiency is induced by triplet self-trapping exciton emission. incorporation La3+-Bi3+ facilitated singlet-triplet increasing lifetime quickening intersystem crossing process. This finding provides reliable method for optimizing properties emerging lead-free halide NCs.