In this work,lead phosphate glasses doubly doped with Tb^3+and Ln^3+(Ln=Eu,Sm)ions were prepared.The excitation and emission spectra of lanthanides ions were recorded.The luminescent properties of lead phosphate glass...In this work,lead phosphate glasses doubly doped with Tb^3+and Ln^3+(Ln=Eu,Sm)ions were prepared.The excitation and emission spectra of lanthanides ions were recorded.The luminescent properties of lead phosphate glasses containing various concentrations of acceptor ions were analyzed.It is observed that luminescence bands corresponding to characteristic transitions of rare earth ions are present on emission spectra measured under direct excitation of Tb^3+.From the emission spectra,the Commission Internationale de I’Eclairage(CIE)chromaticity coordinates(x,y)were calculated in relation to potential application studied systems for white LEDs.Luminescence lifetimes were also determined based on decay measurements and discussed in details.In general,the luminescence spectra and luminescence lifetimes depend on the relative concentrations of the optically active dopants.展开更多
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
基金Project supported by the National Science Centre(Poland)(2015/17/B/ST7/03730)
文摘In this work,lead phosphate glasses doubly doped with Tb^3+and Ln^3+(Ln=Eu,Sm)ions were prepared.The excitation and emission spectra of lanthanides ions were recorded.The luminescent properties of lead phosphate glasses containing various concentrations of acceptor ions were analyzed.It is observed that luminescence bands corresponding to characteristic transitions of rare earth ions are present on emission spectra measured under direct excitation of Tb^3+.From the emission spectra,the Commission Internationale de I’Eclairage(CIE)chromaticity coordinates(x,y)were calculated in relation to potential application studied systems for white LEDs.Luminescence lifetimes were also determined based on decay measurements and discussed in details.In general,the luminescence spectra and luminescence lifetimes depend on the relative concentrations of the optically active dopants.
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.
