Novel efficient Eu3+-activated Ca3Zr2Ga2SiO12 garnet-type red phosphors for WLEDs

To address the practical need for high-efficiency red-emitting phosphors in near-ultraviolet (n-UV) chip-powered white light-emitting diodes (WLEDs), Eu 3+ -doped Ca 3 Zr 2 Ga 2 SiO 12 (CZGSO: x Eu 3+ ) red phosphors were prepared using a conventional high-temperature solid-state reaction method. Subsequently, the optimized phosphor was incorporated with commercial blue and green phosphors to develop a n-UV excited white light-emitting diode (WLED) prototype. A systematic investigation was conducted on the crystal structure, photoluminescence behavior of the phosphors, as well as the practical performance of the device. The findings reveal that Eu 3+ ions successfully occupy the Ca 2+ crystallographic sites within the CZGSO matrix, and all samples retain a single-phase cubic garnet structure with homogeneously distributed constituent elements. The Eu 3+ ions are located in a highly asymmetric local crystal field environment. Under 393 nm excitation, the phosphor exhibits intense red emission centered at 610 nm, dominated by electric dipole transitions, showing good spectral matching with n-UV chips. The optimized composition, CZGSO:0.25Eu 3+ , demonstrates excellent luminescence performance, with a lifetime of 2.19 ms and an IQE of 70.1%. Additionally, this phosphor shows good thermal stability, retaining 85.1% of its initial emission intensity at 423 K, and possesses an activation energy of 0.18 eV. A WLED prototype constructed using this phosphor emits stable white light, achieving a correlated color temperature of 4989 K and a color rendering index of 88.2. Moreover, the spectral profile and color performance remain stable over a wide current range of 100–700 mA. These results suggest that CZGSO:Eu 3+ serves as a highly promising red-emitting phosphor for n-UV pumped WLEDs, representing a competitive option for advanced solid-state lighting.