A Single‐Component Sb/Ho: Cs₂Na_0.9Ag_0.1(In/Bi)Cl₆ White Phosphor with a Record Color Rendering Index of 97.4

Abstract

Abstract The study on phosphors‐converted white light‐emitting diodes (pc‐WLEDs) using lead‐free double perovskites (DPs) as single‐component white phosphors is widely concerned. However, the photoluminescence quantum yields (PLQY) of white luminescence and color rendering index (CRI) of WLED are not satisfactory. Herein, a new Sb/Ho: Cs 2 Na 0.9 Ag 0.1 (In/Bi)Cl 6 single‐component white phosphor with the highest PLQY of 93% and a record CRI of 97.4 is reported. Experimental data and theoretical calculations evidence that in addition to broadband yellow emission of the self‐trapped exciton (STE) recombination, the material also exhibits blue emission from Sb 3+ : 3 P 1 → 1 S 0 transition and red one assigned to Ho 3+ : 5 F 5 → 5 I 8 transition. Steady‐state and time‐resolved PL spectra verify the existence of two energy transfer channels from both Sb 3+ and STE to Ho 3+ dopants. As a demo, Sb/Ho: Cs 2 Na 0.9 Ag 0.1 (In/Bi) Cl6‐based WLED is constructed, showing excellent comprehensive optical performance with specially improved saturation red index R9 and blue one R12. This work provides a novel single‐component rare‐earth doped DP white phosphor for high CRI full‐spectrum solid‐state lighting.