Synthesis and luminescence properties of oxyapatite-type ZnLa4(SiO4)3O:Dy3+ yellow-emitting phosphor for high thermal stability in WLED

The pursuit of white light-emitting diodes (WLEDs) with high color rendering index (CRI) and stable chromaticity remains a significant challenge. This work presents a novel oxyapatite-type ZnLa 4 (SiO 4 ) 3 O:Dy 3+ phosphors as a key component to address this issue. Under 387 nm excitation, the optimized ZnLa 4 (SiO 4 ) 3 O:2 mol%Dy 3+ phosphor exhibits intense emissions at 480, 572, and 663 nm, corresponding to the electronic transitions from the 4 F 9/2 level to the 6 H 15/2 , 6 H 13/2 , and 6 H 11/2 levels, respectively. The concentration quenching mechanism is identified as dipole–dipole interaction, with the optimal doping level at 2 mol%. The phosphor demonstrates excellent color stability, emitting in the yellow region. More importantly, the WLED fabricated with this phosphor exhibited a high CRI ( R a  = 89), a favorable correlated color temperature (CCT = 5740 K), and CIE (Commission International de L’ Eclairage) coordinates (0.327, 0.334) remarkably close to pure white light (0.333, 0.333). These results underscore the great potential of ZnLa 4 (SiO 4 ) 3 O:Dy 3+ phosphors for high-quality solid-state lighting.