Synthesis and study of Y0.9Ln0.1VO4 nanophosphors and Y0.9Ln0.1VO4@SiO2 luminescent nanocomposites with Ln=Eu, Dy, Er

Y0.9Ln0.1VO4 nanophosphors with Ln=Eu, Dy and Er samples were prepared by hydrothermal synthesis and covered with silica (SiO2) by the Stöber method using different reaction times. The synthesized samples were investigated by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and photoluminescence spectroscopy (PL). XRD patterns show diffraction maxima compatible with a zircon-type structure where more intense reflexions are observed in the XRD pattern of Y0.9Er0.1VO4 sample. FTIR spectra of Y0.9Ln0.1VO4@SiO2 samples reveal absorption bands which can be attributed to Si-O-Si and O-Si-O stretching bands and Si-O bending vibration. In all cases, TEM micrographs of Y0.9Ln0.1VO4 phosphors show spherical nanoparticles. Nanoparticles agglomerates covered by a silica were found in TEM micrographs of Y0.9Ln0.1VO4@SiO2 samples. The thickness of the silica coating is dependent on the reaction time. PL measurements show variation of the emission intensity related to the different thickness of the silica coating.