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

[(Gd0.8Lu0.2)(0.9-x)Tb0.1Eux](3)Al5O12 (x = 0-0.1) garnet phosphors have been calcined from their coprecipitated carbonate precursors at 1300 degrees 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 Tb3+ and Eu3+ 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 D-5(4)-> F-7(5) and D-5(0)-> F-7(1) transitions of Tb3+ and Eu3+, respectively. The emission intensities of both Tb3+ and Eu3+ remarkably vary with increasing Eu3+ incorporation, and, as a consequence, the emission color can be readily tuned from approximately green to orange-red. At the optimal Eu3+ concentration of x = 0.03, the energy transfer efficiency was calculated to be similar to 83.2% and the mechanism of energy transfer was analyzed to be electric dipoleedipole interactions. The processes of energy migration among the optically active Gd3+, Tb3+, and Eu3+ ions are discussed in detail. Fluorescence decay analysis found rapidly decreasing lifetime for the Tb3+ emission, conforming to the Tb3+/Eu3+ energy transfer, and the probability of energy transfer is calculated. The [(Gd0.8Lu0.2)(0.9-x)Tb0.1Eux](3)Al5O12 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. (C) 2016 Elsevier B.V. All rights reserved.