Synthesis and photoluminescence properties of garnet red emitting CaY2Al4SiO12:Eu3+ phosphors

Abstract

Eu3+ doped CaY2Al4SiO12 garnet phosphors were synthesized by using the sol-gel method. The crystal structure of the synthesized phosphors was characterized by X-ray diffraction and Rietveld refinements. The results of X-ray diffraction and Rietveld refinements of the powders sintered at 1400 °C showed the formation of a single phase and the effective concentration of Eu3+ ions in this garnet host lattice.The composition of the substitutional solid solutions of CaY2-xEuxAl4SiO12 (x = 0.01, 0.03, 0.06, 0.09, 0.12, and 0.15) exhibit efficient red photoluminescence peaking at 596 nm, which can be assigned to the 5D0 → 7F1 intra-configurational transition of Eu3+ located at the dodecahedral site in the garnet structure. The photoluminescence properties, such as excitation and emission spectra, decay curves, and quantum yield, are presented. The thermal stability of the as-prepared phosphors was determined. Additionally, the optical bandgap for the samples was estimated with UV–visible diffuse reflectance spectra using the Tauc relation. The correlation between the structural features and luminescence properties was determined. These phosphors with high thermal stability and high color purity can be potentially used in white-light-emitting diodes.