Effect of annealing on fluorescence of Ce³⁺-doped silica prepared by sol-gel process

Abstract

We prepared Ce 3+ -doped silica by the sol-gel method and studied the effect of annealing on fluorescence of these samples. Different fluorescence was observed for samples annealed at different temperatures, changing gradually from solution like fluorescence to fluorescence similar to that observed in the Ce 3+ -doped silica prepared by chemical vapor deposition. It was found that the emission intensity first decreased with increasing annealing temperature until 500°C, and then increased with the temperature ranging from 500 to 950°C. Meanwhile, the emission peak showed a large red shift and an obvious broadening. These changes were attributed to the annealing-induced structural evolution in silica: Ce 3+ ions changed from coordinating with water and terminal OH-groups to embedding in silica network.