Structural characterization of SiO2/Zn2SiO4:Ce nanocomposite obtained by sol gel method

Abstract

Ce-doped ZnO nanopowder and ZnO:Ce/silica nanocomposite were synthesized by sol– gel process under supercritical drying (temperature and pressure) of ethanol. Annealing at 1200 C under atmospheric pressure has been achieved for the prepared ZnO:Ce/silica nanocomposite. Xray diffraction (XRD) showed good crystallinity and a ZnO hexagonal wurtzite structure of the as-prepared powder. The average crystallite size is of the order of 78 nm. Crystallites agglomerate to form spheres, hexagons and/or hexagons inserted in tori. The introduction of ZnO:Ce in silica leads to the formation of zinc silicate even before annealing. The heat treatment reduces the intensity of the diffraction peaks and enhanced the formation of this new phase. Photoluminescence (PL) spectra showed that the introduction of ZnO:Ce in silica before annealing reduces the UV lines and red shifts the entire emission. After annealing the PL intensity of the nanocomposite is significantly reduced.