Photoluminescence and time-resolved luminescence spectroscopy of novel NaBa4(BO3)3:Tb3+ phosphor

This paper reports the photoluminescence (PL) properties of Tb3+ in NaBa4(BO3)(3), as well as the time-resolved luminescence properties. The PL excitation spectrum exhibits intense f -> f transition absorption; the PL emission spectrum shows the strongest D-5(4) -> 7F5 emission at 540 nm. The relative intensity of D-5(3) emission is much weaker than that of D-5(4) emission even in the samples with lower Tb3+ concentration. The D-5(3). D-5(4) cross-relaxation produces a marked increase in the D-5(3) decay rate with increasing Tb3+ concentrations and introduces a non-exponential component into the initial part of the decay. The dipole-dipole interaction is found to be responsible for the cross-relaxation. The decay curves of D-5(4) -> 7F5 transition exhibit an initial rise phenomenon. The two exponential fitting indicates that the initial slow rise is attributed to the D-5(3) -> D-5(4) cross-relaxation process. (C) 2011 Elsevier B. V. All rights reserved.