Broadband Green-Yellow KGaSi2O6:Eu2+ Phosphor with Excellent Thermal Stability for Near Ultraviolet-Pumped White-Light-Emitting Diodes

Various types of Eu2+ activated phosphors show potential applications in light emitting diodes. In this work, the Eu2+ activated KGaSi2O6 phosphors were synthesized using high-temperature solid-state reactions. The crystallization and oxidation states, luminescence spectra, decay characteristics, and thermal stability were researched. Depending on excitation of NUV light, the Eu2+ activated KGaSi2O6 phosphors emitted green-yellow light originating from the 4f65d1 → 4f7 transitions of Eu2+. In the light of emission data measured at different temperatures, the activation energy was calculated as 0.33 eV. The warm white light with a correlated color temperature of 3909 K and a color rendering index of 81.9 was emitted by the WLED device consisting of near ultraviolet LED chips, KGaSi2O6:Eu2+ and CaAlSiN3:Eu2+ phosphors.