Thermally robust garnet yellow-green phosphors with near-unity quantum yield for white light-emitting diodes

Broadband green-yellow phosphors remain critical for achieving high-performance white light-emitting diodes (WLEDs), particularly in addressing spectral gaps and improving color rendering. Herein, a novel garnet-type Y 3 Sc 2 Al 3 O 12 :Ce 3 + phosphor is developed via a high-temperature solid-state method, exhibiting intense broadband emission centered at 545 nm with a full width at half-maximum of 115 nm. Structural and spectral analyses reveal that Ce 3+ ions initially occupy Y 3+ sites and progressively substitute Sc 3+ sites at higher doping concentrations, giving rise to multiple luminescent centers. The optimized Y 3 Sc 2 Al 3 O 12 :0.02Ce 3+ sample exhibits a near-unity photoluminescence quantum yield (98.3%) and excellent thermal stability, retaining 85% of its initial emission intensity at 425 K. A prototype WLED fabricated by combining this phosphor with commercial CaAlSiN 3 :Eu 2+ red phosphor and a blue LED chip delivers warm white light with a color rendering index of 87.1 and a correlated color temperature of 4073 K. In addition, the laser-driven luminescence behavior of the phosphor ceramic sheet prepared by hot-pressing sintering were preliminarily investigated. This work provides a new and highly efficient garnet candidate material for WLEDs, and also offers guidance for the further development of high-power solid-state lighting.