Facile preparation of highly efficient Te4+-doped Rb2SnCl6 perovskites for white light-emitting diodes

Lead-free vacancy‐ordered halide double perovskite microcrystals are new alternatives to lead-based halide perovskite materials for lighting applications; however, they are limited by harsh synthesis conditions and low quantum efficiency. Hence, a facile solution recrystallization method was used to synthesize Te4+-doped Rb2SnCl6 phosphors. Via Te4+ doping, the phosphors show a yellow–green emission at 550 nm and a broadband emission line width of approximately 97 nm, achieving a high photoluminescence quantum yield of 74.2%, arising from the Te4+ 1S0 →3P1 self-trapping exciton transition. The Te4+-doped Rb2SnCl6 microcrystals are subsequently used to fabricate a white light-emitting diode device, which shows a high color-rendering index of 97.1 and a correlated color temperature of 4739 K. This work reports a facile method to synthesize alloy double perovskite phosphors, opening up new avenues for the development of environment-friendly lighting applications.