Dual-Band-Tunable White-Light Emission from Bi 3+ /Te 4+ Emitters in Perovskite-Derivative Cs 2 SnCl 6 Microcrystals.

Luminescent metal halides have attracted considerable attention in next-generation solid-state lighting because of their superior optical properties and easy solution processibility. Herein, we report a new class of highly efficient and dual-band-tunable white-light emitters based on Bi 3+ /Te 4+ co-doped perovskite derivative Cs 2 SnCl 6 microcrystals. Owing to the strong electron-phonon coupling and efficient energy transfer from Bi 3+ to Te 4+ , the microcrystals exhibited broad dual-band white-light emission originating from the inter-configurational 3 P 0,1 → 1 S 0 transitions of Bi 3+ and Te 4+ , with good stability and a high photoluminescence (PL) quantum yield of up to 68.3 %. Specifically, a remarkable transition in Bi 3+ -PL lifetime from milliseconds at 10 K to microseconds at 300 K was observed, as solid evidence for the isolated Bi 3+ emission. These findings provide not only new insights into the excited-state dynamics of Bi 3+ and Te 4+ in Cs 2 SnCl 6 , but also a general approach to achieve single-composition white-light emitters based on lead-free metal halides through ns 2 -metal ion co-doping.