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

The study on phosphors-converted white light-emitting diodes (pc-WLEDs) using lead-free double perovskites (DPs) as single-component white phosphors has been 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: Cs₂Na_0.9Ag_0.1(In/Bi)Cl₆ 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 Sb³⁺: ³P₁→¹S₀ transition and red one assigned to Ho³⁺: ⁵F₅→⁵I₈ transition. Steady-state and time-resolved PL spectra verify the existence of two energy transfer channels from both Sb³⁺ and STE to Ho³⁺ dopants. As a demo, Sb/Ho: Cs₂Na_0.9Ag_0.1(In/Bi)Cl₆ based WLED has been 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.

DOI: https://doi.org/10.1002/adfm.202407584