Abstract: (La,Gd)PO₄:RE³⁺ (RE=Eu or Tb) phosphors were prepared by co-precipitation method. It was found that the IR spectra of LaPO₄ and GdPO₄ were quite similar, the difference was that both stretching frequencies and bending frequencies of GdPO₄ were higher than those of LaPO₄. The VUV excitation intensity of (La,Gd)PO₄:RE³⁺ is enhanced with the increasing of Gd³⁺ content, implying the intermediate role of Gd³⁺ in energy transfer from host absorption band to RE³⁺. It was also found from XPS that the LaPO₄ valance band was formed by the 2p level of O^2-, whereas the GdPO₄ valance band was composed of the 2p level of O^2-and the 4f level of Gd³⁺, showing the differences in band structures between LaPO₄ and GdPO₄, which may have influence on the VUV spectroscopic properties of (La,Gd)PO₄:RE³⁺.

Key words: (La,Gd)PO₄：RE³⁺, IR, Vaccum ultraviolet(VUV) spectrum, Energy transfer, XPS