Photoluminescence study of ZnO–SiO2 nanostructures grown in silica matrix obtained via sol–gel method

ZnO–SiO2 nanocomposite consisting of ZnO nanostructures grown in SiO2 (silica) host matrix was obtained via hydrolysing Tetraethylorthosilicate (TEOS) with ethanolic solution of Zinc nitrate hexahydrate using Sol–gel method. Systematic study of the key parameters (precursor, concentration, and heat treatment conditions) has been taken into account that influences the growth mechanism and morphology of the as formed nanostructures. X-ray diffraction (XRD) analysis was used to determine the crystallinity, particle size and lattice parameter. Scanning electron microscopy (SEM) of the sample reveals the formation of ZnO nanostructures in silica matrix. Room temperature Photoluminescence (PL) measurement of the sample was done to understand the nature of possible defect level transition responsible for visible and rarely observed orange–red emissions in ZnO. This study reveals the usefulness of the nanocomposites as a luminescent material.

► ZnO nanostructures embedded in SiO2 matrix is synthesized by sol–gel method. ► XRD confirms the formation of ZnO–SiO2 composite and no phase of Zn2SiO4 is found. ► Luminescence property of the material depends on the nanostructures formed. ► PL spectrum covers full visible range with orange–red band as the dominant one. ► NBE excitonic UV emission band is absent in the PL emission spectra.