Sb3+ and Sm3+ co-doped lead-free Cs2NaInCl6 double perovskite nanocrystals for single-component cold white emitter

Metal halide perovskites exhibit promising prospect in light-emitting diodes, solar cells, photodetectors and bioimaging. However, the workhorse of metal halide perovskites relies on toxicity lead element, which severely damages human body and environment. Among lead-free perovskites, Cs2NaInCl6 double perovskite is one of the most promising candidates because of its great stability and easy synthesis, but suffers inadequate optical performance. Here, we doped Sb3+ and Sm3+ into Cs2NaInCl6 nanocrystals by a hot injection method. Cs2NaInCl6:Sb3+ exhibits blue emission at 447 nm. Cs2NaInCl6:Sm3+,Sb3+ nanocrystals simultaneously generate the blue emission of Sb3+ and the multiple emissions of Sm3+ at 565, 602, 650 and 710 nm. With the increase of Sm3+ feed ratio, the emission color of Cs2NaInCl6:Sm3+,Sb3+ gradually moves to cold white region at (0.27, 0.28) in CIE chromaticity diagram and correlated color temperature of 11,840 K. This work shows the potential application of Cs2NaInCl6:Sm3+,Sb3+ nanocrystals as a single-component cold white emitter.