Luminescent properties of Eu3+ in nano-matrix of SiO2

Eu3+-doped SiO2 matrix materials were prepared by sol-gel technique. The samples were characterized by the modern analysis techniques such as the fluorescence spectrum, atomic force microscope (AFM) and scanning electron microscope (SEM) and so on. The influences of annealing temperature and doping concentration on the luminescent properties were studied systematically, and the luminescence mechanism was investigated. When the films were excited at 258 nm, double peak at 620 nm and 667 nm were observed, which was rarely seen, and at 620 nm the emission intensity reached the strongest, which suggested Eu3+ ions lay in the coordination environment of the lower symmetry. The annealing temperature made great effect on the emission spectroscopy, the luminescence intensity of the film annealed at 900°C was the strongest. With the variations of doping concentration, the distance between Eu3+ and O2 was changed. At the same UV excitation, the outer electron of O2-migrated to the 4f orbit of Eu3+ caused the energy changed, and the spectrum position removed.