Synthesis and characterization of Ce3+ doped silica (SiO2) nanoparticles

A series of silica doped with different mol percentages of Ce3+ concentration was synthesized using a sol–gel method to determine the dependence of photoluminescence wavelengths and intensity on the concentrations of the dopants. Sol–gel glasses are porous networks that have been densified through chemical processing and heat treatment. Rare-earths (REs) are insoluble in silica; due to this insolubility RE ions in silicate glasses enter as network modifiers and compete for non-bridging oxygen in order to complete their coordination. The morphological, structural, thermal and optical properties of the phosphors were characterized by X-ray diffraction, scanning electron microscopy, UV–vis absorption, photoluminescence, thermogravimetric analyses and differential scanning calorimeter. Silica (SiO2) gel containing Ce3+ ions was sputter coated with Au (gold) in order to monitor surface morphology of the samples. The highest emission intensity was found for the sample with a composition of 0.5 mol% Ce3+. Cerium doped silica glasses had broad blue emission corresponding to the 2D3/2–2FJ transition at 448 nm but exhibited apparent concentration quenching above concentrations of 0.5 mol% Ce3+.