Blue luminescence and structural properties of Ce(3+)-activated phosphosilicate apatite Sr5(PO4)2(SiO4)

Blue-emitting phosphors of the Ce(3+)-activated phosphosilicate Sr(5)(PO(4))(2)SiO(4) with an apatite structure were prepared via a conventional solid-state reaction method. The X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectra, time-resolved luminescence, thermal quenching and luminescence decay curves (lifetimes) were applied to characterize the phosphors. The effects of the Ce(3+) activator concentration on the phase evolution and luminescence properties were investigated. Sr(5-5x)Ce(5x)(PO(4))(2)SiO(4) (x = 0.03) exhibits the brightest blue emission with CIE coordinates of (x = 0.185, y = 0.165) and a quantum efficiency of 46%. The crystallographic site of the Ce(3+) ions in the Sr(5)(PO(4))(2)SiO(4) lattice was identified and discussed. There is only one distinguishable crystallographic Ce(3+) site occupied on a Sr(ii) site in the Sr(5)(PO(4))(2)SiO(4) lattices, which results in a typical doublet emission band. The wavelengths of the excitation and emission bands show a red shift with increasing Ce(3+) doping concentration. The luminescence features of the Ce(3+) ions were discussed on the base of the crystal structure. The thermal stability of the blue-emitting phosphors was evaluated by the temperature-dependent luminescence and the activation energy of the thermal quenching.