Xiaoluan Liang

Luminescence properties of Tb3+–Sm3+ codoped glasses for white light emitting diodes

Photoluminescence properties of silicate and borosilicate glasses codoped with Tb3+ and Sm3+ ions have been characterized by excitation and emission spectroscopies. When excited by ultraviolet light the glasses emit a combination of green and orange-red wavelengths giving white light. The ratio of the intensities of orange-red to green emissions can be tuned by varying both the concentration of the Sm3+ ion and an the composition of the glass matrix. The excitation and emission spectra show a self-quenching effect for the Sm3+ ions and an energy transfer from Tb3+ (D45) to Sm3+ (G5∕24).

Green emission from Eu{sup 2+}/Dy{sup 3+} codoped SrO-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3} glass-ceramic by ultraviolet light and femtosecond laser irradiation

A spectroscopic investigation of Eu{sup 2+}/Dy{sup 3+} codoped SrO-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3} glass-ceramic is presented. The sample exhibits green emission excited by ultraviolet (UV) light and near-IR femtosecond (fs) laser. The emission profile obtained by near-IR fs laser irradiation is similar to that by UV excitation, indicating that both of the emissions come from 5d {yields} 4f transition of the Eu{sup 2+} ions. The relationship between the upconversion luminescence (UCL) intensity and pump power reveals a two-photon process in the conversion of near-IR radiation to the green emission. The possible mechanism of UCL from such glass-ceramic is proposed.