Sol–gel derived Y(PO3)3 polyphosphate: Synthesis and characterization

The yttrium polyphosphate Y(PO3)3 has been synthesized by an all-alkoxide sol–gel route and characterized by X-ray diffraction and IR spectroscopy. The spectroscopic properties of 5% Eu3+ doped samples prepared by the sol–gel process were investigated under site-selective laser excitation in the 5D0 and 5D2 levels of trivalent europium ions, and compared with those of similar compounds synthesized through the conventional solid state reaction. Results showed that one distorted crystallographic site is occupied by Eu3+ ions when spectra are recorded at room temperature. A second site appeared for low temperature measurements in agreement with a phase transition evidenced by a differential scanning calorimetry analysis. These optical results are in disagreement with the already known monoclinic structure of Y(PO3)3 where four sites have been identified at room temperature for lanthanide ions.