In present work, the optical and structural properties of silica sol-gel glasses and glass-ceramic materials singly- and dou- bly-doped with Eu3＋ and Gd3＋ ions were investigated. The optical properties of studied sy...In present work, the optical and structural properties of silica sol-gel glasses and glass-ceramic materials singly- and dou- bly-doped with Eu3＋ and Gd3＋ ions were investigated. The optical properties of studied systems were determined based on absorption, excitation and emission spectra as well as luminescence decay analysis. Conducted studies clearly indicated a significant enhance- ment of visible emission originated from Eu3＋ ions as a result of changing the excitation mechanism, via Gd3＋Eu3＋ energy transfer. The luminescence intensity R-ratio was analyzed before and after heat-treatment process upon excitation at λex=393 nm and λex=273 nm. Moreover, the influence of excitation wavelength on luminescence decay time of the 5D0 excited state was also analyzed. The GdS＋-Eu3＋ energy transfer efficiencies for precursor and annealed samples were calculated based on luminescence lifetime of the 6p7/2 level of Gd3＋ ions. The X-ray diffraction measurements were conducted to verify the nature of obtained sol-gel materials. In re- sult, the formation of orthorhombic GdF3 nanocrystal phase dispersed in amorphous silica glass host was identified after annealing. Obtained results clearly indicated an incorporation of Eu3＋ activators into formed GdF3 nanocrystals. Thus, conducted heat-treatment process led to considerable changes in surrounding environment around Eu3＋ ions. Actually, it was found that en- ergy transfer phenomenon and heat-treatment process were responsible for significant improvement of Eu3＋ luminescence in stud- ied sol-gel samples.展开更多
文摘In present work, the optical and structural properties of silica sol-gel glasses and glass-ceramic materials singly- and dou- bly-doped with Eu3＋ and Gd3＋ ions were investigated. The optical properties of studied systems were determined based on absorption, excitation and emission spectra as well as luminescence decay analysis. Conducted studies clearly indicated a significant enhance- ment of visible emission originated from Eu3＋ ions as a result of changing the excitation mechanism, via Gd3＋Eu3＋ energy transfer. The luminescence intensity R-ratio was analyzed before and after heat-treatment process upon excitation at λex=393 nm and λex=273 nm. Moreover, the influence of excitation wavelength on luminescence decay time of the 5D0 excited state was also analyzed. The GdS＋-Eu3＋ energy transfer efficiencies for precursor and annealed samples were calculated based on luminescence lifetime of the 6p7/2 level of Gd3＋ ions. The X-ray diffraction measurements were conducted to verify the nature of obtained sol-gel materials. In re- sult, the formation of orthorhombic GdF3 nanocrystal phase dispersed in amorphous silica glass host was identified after annealing. Obtained results clearly indicated an incorporation of Eu3＋ activators into formed GdF3 nanocrystals. Thus, conducted heat-treatment process led to considerable changes in surrounding environment around Eu3＋ ions. Actually, it was found that en- ergy transfer phenomenon and heat-treatment process were responsible for significant improvement of Eu3＋ luminescence in stud- ied sol-gel samples.
