Color-tunable properties based on complex anion substitution in Eu2+ doped Ca8Sc2(PO4)6-y(SiO4)1+y phosphor

We synthesized and investigated the effect of Eu 2+ ions doping in a novel phosphor-silicate Ca 8 Sc 2 (PO 4 ) 6 (SiO 4 ) phosphor. The structure and photoluminescence properties were determined by X-ray powder diffraction Rietveld refinement , diffuse reflection spectra, emission-excitation spectra, decay curves and temperature dependence spectra. The phosphors showed an asymmetric broad-band blue emission (Eu 2+ ) with peak at 470 nm. Furthermore, we presented the Ca 7.96 Sc 2 (PO 4 ) 6- y (SiO 4 ) 1+ y :0.04Eu 2+ phosphors by co-substituting [Eu 2+ -Si 4+ ] for [Ca 2+ -P 5+ ], and different behaviors of luminescence evolution in response to structural variation were verified among the series of phosphors. The results were attributed to the presence of multi Ca 2+ sites, resulting in the mixing of blue and green emissions for Eu 2+ ions. The complex anion substitution of [PO 4 ] 3- by [SiO 4 ] 4- induced an increased crystal field splitting of the Eu 2+ ions, which caused a decrease in emission energy from the 5d excited state to the 4f ground state and a resultant red-shift from 470 nm to 520 nm. All the properties indicated that the Ca 8 Sc 2 (PO 4 ) 6 (SiO 4 ):Eu 2+ phosphors have potential application for color-tunable WLEDs .