STUDY OF EU-3+-DOPED LUMINESCENCE GLASSES PREPARED BY A SOL-GEL PROCESS

The formation of Eu3+-doped luminescence glasses prepared by sol-gel techniques and the spectroscopic properties of Eu3+ ions in dried gels and gel glasses were investigated. The results showed that most residual water and organic molecules in the dried gel had vaporized in the temperature range from room temperature to 200-degrees-C, and careful heat treatment of the dried gel in a lower temperature range was required to obtain bulk Eu3+-doped luminescence glass. It was also found that the ratio of emission intensities of the 5D0 --> F-7(1) transition and 5D0 --> F-7(2) transition in dried gels was very different from that in gel glasses. The dependence of concentration on the Eu3+ emission intensity in dried gels and gel glasses was also investigated. In gel glasses, the dependence of concentration on the luminescence in the range 0.5-4 mol% Eu2O3 did not reveal any concentration quenching. Conversely, the optimum concentration of Eu2O3 for maximum luminescence intensity in dried gels was approximately 1 mol%. The phonon-assisted resonant energy transfer theory is expected to explain the concentration quenching of Eu3+ ion luminescence in dried gels.