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Preparation of Y(PO3)3 polyphosphate was investigated by sol–gel process and solid state synthesis. Crystallization temperature range and purity of samples arising from both synthesis methods were compared. XRD patterns recorded from powders annealed at different temperature evidenced that the stability domain of Y(PO3)3 is much wider for sol–gel derived samples. Furthermore 31P NMR analysis demonstrated the presence of YPO4 impurity along with Y(PO3)3 resulting from solid state route for any sintering temperature. Regarding the sol–gel procedure, effects of the elimination of KCl by-product on the presence of carbon residues in the final materials was studied by IR and Raman spectroscopies as well as EPR measurements. It was shown that when KCl is removed at the end of the synthesis, the crystallization of Y(PO3)3 phase takes place over a very short domain and leads to grey black powder unsuitable for further optical investigations. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: Sol–gel TiO2 thin films have been loaded with platinum nano-particles via their immersion within a Pt4+ precursor liquid solution exposed to UV light. Mechanisms involved in the photo-induced formation of platinum particles have been studied by UV/visible spectroscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray analysis, scanning electron microscopy, and transmission electron microscopy. According to studied mechanisms, it is shown that the amount, size, and structural state of photo-generated platinum particles dispersed at a solid surface can flexibly be monitored. [Copyright &y& Elsevier]