Visible emission and energy transfer in Tb3+/Dy3+co-doped phosphate glasses

In this work, we systematically study the spectroscopic properties of Tb3+/Dy(3+)co-doped phosphate glasses in the visible spectral region and explore the sensitization role of Dy(3+)in the enhancement of visible fluorescence of Tb(3+)ions. Judd-Ofelt parameters omega(2)and omega(4)/omega(6)of the phosphate glass as host for Tb(3+)are calculated as 21.60 x 10(-20) cm(2)and 0.73, respectively, based on the measured spectral absorption. Multiple energy transfer (ET) routes from Dy(3+)to Tb(3+)and their efficiencies are characterized, and the enhanced fluorescence properties of Tb(3+)are investigated, including the emission spectral strength and the spontaneous emission lifetime as functions of Dy(3+)doping concentration. The efficient nonradiative ET processes between Dy(3+)and Tb(3+)allow a moderate concentration level of Tb(3+)to achieve favorably stronger spectral absorption at blue and ultraviolet wavelengths. Tb3+/Dy(3+)co-doped phosphate glass shows promising potential for phosphors and lasing operation at visible wavelengths.