Tunable white light and energy transfer of Eu2+-Tb3+-Eu3+ tri-activated glasses synthesized in air

An ever increasing demand for white light-emitting diodes (W-LEDs) results in the gradual growth of research on functionalized luminescent glasses. In this paper, single-composition tunable white-emitting Eu2+-Tb3+-Eu3+ tri-activated glasses were synthesized by melt quenching method without additional reducing atmosphere. The coexistence of Eu2+ and Eu3+ was confirmed by ultraviolet-visible transmission spectra, photoluminescent spectra, fluorescence decay curves, and X-ray photoelectron spectroscopy. Tb3+ can act as bridge to connect Eu2+-Eu3+ luminescent centers by energy transfer. Tone-tunable white light can be achieved by coupling the emission centered at 412, 541, and 612 nm contributed from Eu2+, Tb3+, and Eu3+, respectively. By adjusting the relative content of Eu2+/Tb3+/Eu3+, ideal chromaticity coordinates of (0.33, 0.33) can be achieved under excitation of ultraviolet light. High thermal stability and tiny chromaticity shift were exhibited in samples. These results suggest that Eu2+-Tb3+-Eu3+ tri-activated glasses have great potential application in ultraviolet-driven W-LEDs.