Spectroscopic properties of Ce doped silica annealed at different temperatures

Ce³⁺-doped silica was synthesized by sol-gel technique. The absorption band at 252 nm of Ce³⁺-doped silica is close to the main absorption band of Ce(NO₃)₃ solution. Three different luminescence bands were observed in the samples annealed at temperatures from 100 to 1200 °C, and the intensity of these luminescence bands changed with the alteration of the heat-treating temperatures. In addition to two well-known main luminescence bands of 4f-5d transition of Ce³⁺ with the wavelength at 357 and 450 nm, a rarely reported luminescent band with the wavelength at 344 nm was also observed, which was attributed to some kind of oxygen-related defects of silica.