An ultra-broadband green-emitting phosphor K2ZnSi3O8:Eu2+ with excellent thermal recovery for high-quality WLEDs

An ultra-broadband green-emitting phosphor K 2 ZnSi 3 O 8 :Eu 2+ with FWHM of 111.8 nm was developed via multi-site occupation of Eu 2+ . • Mg 2+ substitution for Zn 2+ induces local lattice stiffening and defect passivation, boosting PL intensity by 120% . • The optimized phosphor exhibits enhanced thermal stability with increased activation energy (0.261 eV vs. 0.251 eV) and complete intensity recovery after thermal cycling. • A warm WLED fabricated with KZn 0.99 Mg 0.01 SiO 8 :0.01Eu 2+ and commercial red phosphor achieves high color rendering index (Ra = 94.2) and low CCT (3552 K). • This cationic substitution strategy offers an effective route to simultaneously enhance luminescence efficiency, thermal stability, and moisture resistance in rare-earth-doped phosphors. Efficient broadband green-emitting phosphors are essential for human-centric healthy lighting. Herein, an ultra-broadband green-emitting phosphor, K 2 ZnSi 3 O 8 :Eu 2+ , was synthesized by high temperature solid-state reaction method for high-quality white light-emitting diodes (WLEDs). Under ultraviolet excitation, the phosphor exhibits a broad emission band spanning from 400 to 750 nm, peaking at 505 nm with a full width at half maximum (FWHM) of 111.8 nm, which originates from the multi-site occupation of Eu 2+ ions. Moreover, structural engineering via Mg 2+ substitution for Zn 2+ effectively enhances the material's performance. K 2 Zn 0.99 Mg 0.01 Si 3 O 8 :Eu 2+ , shows a 120% increase in emission intensity and improved thermal stability. Finally, a warm WLED fabricated this phosphor with a commercial red phosphor exhibits excellent color rendering index (Ra = 94.2) and a warm correlated color temperature (CCT) of 3552 K, demonstrating its promising application in high-quality healthy solid-state lighting.