Temperature-dependent nonradiative energy transfer from Gd3+ to Ce3+ ions in co-doped LuAG:Ce,Gd garnet scintillators

Energy transfer from donor Gd3+ to acceptor Ce3+ ions was studied in low doped lutetium aluminum garnet, LuAG:Ce,Gd. High purity single crystalline films were prepared by liquid phase epitaxy. The mechanism of nonradiative energy transfer from P-6(J) (Gd3+) multiplet to crystal field split (5)d(2) (D-2) states of Ce3+ was established as long-range dipole-dipole interaction and the average critical transfer distance between Gd3+ and Ce3+ ions was found similar to 14 angstrom at room temperature. It is shown that the single step energy transfer between donor-acceptor pairs is dominant while migration of excitation energy within the donor Gd3+ subsystem is only a small perturbation in the energy transfer mechanism in the studied low doped garnets. (C) 2015 Elsevier B.V. All rights reserved.