Preparation and Photoluminescence Properties of Eu²⁺−Doped Oxyapatite-Type Sr_xLa_10−x (SiO₄)₆O_3−x/2

Eu²⁺−doped oxyapatite Sr_xLa_10−x(SiO₄)₆O_3−x/2 phosphors are prepared by solid-state reaction at high temperatures under reducing atmosphere. Their crystal structures and photoluminescence are investigated by x-ray diffraction (XRD) and fluorescence spectroscopy, respectively. The XRD results indicate that the samples are pure oxyapatite phase (P6₃/m space group). The fluorescence spectra show two peaks corresponding to two sites (4f and 6h sites) for Eu²⁺ in the host lattice. As the Eu²⁺ content influences the intensity ratio of the two observed emission peaks, the photoluminescence mechanism is discussed.