Fluorescence properties with red-shift of Eu2+ emission in novel phosphor-silicate apatite Sr3LaNa(PO4)2SiO4 phosphors

A series of Eu2+-activated novel phosphor-silicate apatite Sr3LaNa(PO4)2SiO4 phosphors were synthesized by solid-state reaction. The X-ray diffraction (XRD) and Rietveld refinement, diffuse reflectance spectra, luminescent spectra, decay curves and thermal quenching properties were applied to characterize the obtained phosphors. The XRD result revealed that all the samples possessed only a single phase with hexagonal structure and the doping of Eu2+ ions were successfully incorporated into the crystal lattice. The reflectance spectra showed an obvious red-shift of the wavelength from 400 to 700 nm with increasing Eu2+ ion concentration. The three different crystallographic sites of Eu2+ ions had been confirmed by their lifetimes. All the samples exhibited broad absorption bands from 200 to 450 nm, revealing the phosphor-silicate phosphor interesting for application in the near-UV used phosphor-converted LED chips. These results suggested that the Eu2+-activated phosphor-silicate Sr3LaNa(PO4)2SiO4 phosphors have the potential for near-UV pumped white-light-emitting diodes (w-LEDs).