Preparation And Luminescence Properties Of RE³⁺(RE=Eu, Tb) And Ga³⁺ Co-doped SiO₂ Materials

In Cathode Ray Tube and Tri-phosphor, Cathode Ray Tube lacks blue fluorescence especially. RE³⁺(RE=Eu, Tb) and Ga³⁺ co-doped SiO₂ materials were prepared by sol-gel method and the structure of the materials were investigated by IR and XRD. The results indicate that materials were in amorphous phase and SiO₂ net structure was still observed in annealed samples, the doped concentration of RE³⁺ and Ga³⁺ were too low to influence the SiO₂ network structure. The three dimension fluorescence spectra, excitation and emission spectra were used to characterize the RE³⁺ and Ga³⁺ co-doped SiO₂ luminescent materials. The results indicate that the three dimension fluorescence spectra were according with excitation and emission spectra. In Ga³⁺ and Eu³⁺ co-doped SiO₂ materials, it is approve that 400℃annealed sample excited by 393 nm showed the characteristic emission of Eu³⁺ at 576 nm(5D0-7F0), 588 nm(5D0-7F1), 612 nm(5D0-7F2). And it is found that emission from 5D0-7F1 quenches with high temperature. Doped with Ga³⁺ can be made the sample radiate blue fluorescence at 460 nm. It has less influence with emission intensity of Eu³⁺ but has great effect with blue fluorescence intensity of Ga³⁺ when sample exited by 270, 290, 318 and 380 nm. So materials can be made to radiate different color fluorescence by varying excitation wavelength. In Tb³⁺ and Ga³⁺ co-doped materials, the three dimension fluorescence spectra confirm the emission wavelength of 544 nm and excitation wavelength of 230 nm. When excited by 230 nm, 5D4-7FJ(J=4,5,6) and ⁵D₃-⁷F₆ transition were obtained in emission spectra. It is found that emission from ⁵D₃-⁷F₆ quenches with high temperature. 5D4-7F6 and ⁵D₄-⁷F₅ transition of sample were all activated, but induce the intensity of blue fluorescence at 460 nm. In order to investigate the influence factors of luminescence intensity, annealing temperature, Ga³⁺ ions and RE³⁺ ions concentration in RE³⁺ and Ga³⁺ co-doped silicate materials were discussed, respectively.