Analysis of Tb3+ luminescence by direct transfer and migration in YPO4

The photoluminescence behavior of (Y1-xTbx)PO4 phosphor was investigated by measuring emission and excitation spectra, and decay curves. The relative emission intensity and the decay time have been monitored as a function of Tb3+ concentration for both D-5(4) - F-7(j) and D-5(3) - F-7(j) transitions . The decay behavior of D-5(4) - F-7(j) transition, for which well known cr oss-relaxation has been accepted as a main factor was analyzed by direct qu enching mechanism on the basis of dipole-dipole interaction. It is. however , impossible to characterize the D-5(4) - F-7(j) transition using the direc t quenching scheme. In fact, the decay curves of D-5(4) - F-7(j) transition could be analyzed by intercenter energy migration. Another type of cross-r elaxation was suggested to explain the quenching of D-5(4) F-7(j) transitio n. (C) 2000 The Electrochemical Society. S0013-4651(99)11-095-4. All rights reserved.