Host Sensitized White Luminescence from ZnGa2O4 : Dy3 + Phosphor

Abstract

Dysprosium-doped zinc gallate phosphors with the nominal formulas were prepared by the high-temperature conventional solid-state reaction technique, the dopant concentration being varied in the range . and samples were also prepared for comparison for a dopant concentration of . Only the intrinsic self-activated emission of the host is observed in the photoluminescence emission spectra of , while both the host emission band and characteristic emission lines of are observed for and phosphors. The luminescent intensity differs in the phosphors due to the different energy-transfer rates from the respective hosts to the luminescent centers. Photoluminescent studies reveal the fact that ions replace ions in the host lattice at their octahedral sites. The source of white luminescence in the doped samples is the nonradiative resonant energy transfer via exchange interaction between the host and the activator. The CIE coordinates of the 2.5 atom % -doped sample (0.32, 0.33) matches well with achromatic white (0.33, 0.33) on the chromaticity diagram.