Tb3+/Eu3+ codoping of Lu3+-stabilized Gd3Al5O12 for tunable photoluminescence via efficient energy transfer.

[(Gd 0.8 Lu 0.2 ) 0.9− x Tb 0.1 Eu x ] 3 Al 5 O 12 ( x = 0–0.1) garnet phosphors have been calcined from their coprecipitated carbonate precursors at 1300 °C. Detailed materials characterizations are done via XRD, FE-SEM, BET, particle sizing, PL/PLE, and fluorescence decay analyses. The phosphors, with excellent dispersion and uniform particle size and shape, simultaneously exhibit the characteristic Tb 3+ and Eu 3+ emissions with the strongest peaks located at 545 nm (green) and 592 nm (orange red) under the optimal excitation wavelength of 275 nm, which correspond to the 5 D 4 → 7 F 5 and 5 D 0 → 7 F 1 transitions of Tb 3+ and Eu 3+ , respectively. The emission intensities of both Tb 3+ and Eu 3+ remarkably vary with increasing Eu 3+ incorporation, and, as a consequence, the emission color can be readily tuned from approximately green to orange-red. At the optimal Eu 3+ concentration of x = 0.03, the energy transfer efficiency was calculated to be ∼83.2% and the mechanism of energy transfer was analyzed to be electric dipole–dipole interactions. The processes of energy migration among the optically active Gd 3+ , Tb 3+ , and Eu 3+ ions are discussed in detail. Fluorescence decay analysis found rapidly decreasing lifetime for the Tb 3+ emission, conforming to the Tb 3+ → Eu 3+ energy transfer, and the probability of energy transfer is calculated. The [(Gd 0.8 Lu 0.2 ) 0.9− x Tb 0.1 Eu x ] 3 Al 5 O 12 solid-solutions developed in this work may serve as a new type of phosphor that hopefully meets the requirements of various lighting, optical display, and scintillation applications. [ABSTRACT FROM AUTHOR]