Sr8ZnSc(PO4)7:Eu2+,Hf4+: A Novel Single-Host White Light-Emitting Phosphor Based on Defect Engineering

Single-host white light-emitting phosphors have been one of the research hotspots in the field of white light-emitting diodes (WLEDs) in recent years. Herein, white light emission is realized in Sr 8 ZnSc(PO 4 ) 7 :Eu 2+ phosphor by using the defect engineering strategy, i.e. the heterovalent substitution of Sc 3+ with Hf 4+ . Based on the charge compensation mechanism of the substitution, electron paramagnetic resonance (EPR) analysis confirms a positive correlation between cation vacancy concentration and dopant content. Photoluminescence spectra indicates that there are two different emissions at 408 and 520 nm in the phosphor. Under 335 nm excitation, the SZSP:0.02Eu 2+ ,0.03Hf 4+ exhibits cold white light emission with CIE coordinates (0.2992, 0.3214) and an enhanced color rendering index (Ra = 80.02), showing superior performance compared to commercial YAG:Ce 3+ phosphor. This work not only elucidates the critical role of Hf 4+ dopants in defect engineering but also establishes a novel material for developing high-efficiency phosphors with tunable color temperature for WLED applications.