Efficient and tunable photoluminescence for terbium-doped rare-earth-based Cs2NaYCl6 double perovskite

Lead-free double perovskite materials with efficient and stable self-trapped exciton (STE) emissions show enormous potential for next-generation solid-state lighting. However, the low-emission efficiency and difficulty of spectral regulation are two major obstacles to their application. Here, all-inorganic rare-earth-based double perovskite Cs 2 NaYCl 6 single crystals with strong blue emissions were reported as effective hosts to accommodate lanthanide ion doping. By controlling the introduction of Tb 3 + ions and efficient energy transfer from the STEs to the dopants, the emission color of Cs 2 NaYCl 6 single crystals was flexibly modulated from blue to green. The quantum yields were also significantly improved from 10% to 78.81% by optimizing the Tb 3 + ion concentration. Further, stable light-emitting diode prototypes based on Cs 2 NaYCl 6 color conversion materials were fabricated to demonstrate the practical applications of rare-earth-based double perovskite.