摘要：Intrinsic broadband photoluminescence(PL)of self-trapped excitons(STEs)are systematically studied in lead-free double perovskite nanocrystals(NCs).It is clarified that bandgap(direct/indirect)has important influence on the PL properties of STEs:indirect bandgap NCs exhibit strong exciton-phonon coupling which results in non-radiative STEs,while direct bandgap NCs exhibit moderate exciton-phonon coupling,inducing bright STE ***,by alloying K+and Li+ions in Cs2AgInCl6 NCs,the NCs exhibit broadband white-light ***-carrier dynamics study indicates that the efficient white-light emission originates from the further suppressed non-radiative processes of the STEs in the direct bandgap *** work may deepen the understanding of STEs and guide the design of highperformance lead-free perovskites.