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

In this work, we systematically study the spectroscopic properties of Tb 3+ /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 Ω 2 and Ω 4 /Ω 6 of the phosphate glass as host for Tb 3+ are calculated as 21.60 × 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. Tb 3+ /Dy 3+ co-doped phosphate glass shows promising potential for phosphors and lasing operation at visible wavelengths.