Tunable dual-emission of Sb, HoCo-doped CsNaScClsingle crystals for light-emitting diodes.

Lead-free halide double perovskites are considered as one of the most promising materials in optoelectronic devices, such as solar cells, photodetectors, and light-emitting diodes (LEDs), due to their environmental friendliness and chemical stability. However, the extremely low photoluminescence quantum yield (PLQY) of self-trapped excitons (STEs) emission from lead-free halide double perovskites impedes their applications. Herein, Sbions were doped into rare-earth-based double perovskite CsNaScClsingle crystals (SCs), resulting in a large enhancement of PLQY from 12.57% to 87.37%. Moreover, by co-doping Sband Hointo CsNaScClSCs, the emission color can be tuned from blue to red, due to an efficient energy transfer from STEs to Hoions. Finally, the synthesized sample was used in multicolor LED, which exhibited excellent stability and optical properties. This work not only provides a new strategy for improving the optical properties of CsNaScClSCs, but also suggests its potential application in multicolor LEDs.