Color-tunable photoluminescence phosphors of Ce3+ and Tb3+ co-doped Sr2La8(SiO4)6O2 for UV w-LEDs

A series of new luminescent emission-tunable phosphors Sr2La8(SiO4)(6)O-2:Ce3+, Tb3+ with apatite structure have been synthesized by a high temperature solid-state reaction. The phase structure, photoluminescence emission and excitation spectra, lifetime, as well as the effect of Tb3+ concentration are investigated to characterize the resulting samples. The critical distance was calculated to be 8.26 A by using the concentration quenching method. The intense green emission was observed in the Sr2La8(SiO4)(6)O-2:Ce3+, Tb3+ phosphors on the basis of the efficient energy transfer from Ce3+ to Tb3+ with an efficiency of 68.55%. And a possible mechanism of the energy-transfer from Ce3+ to Tb3+ ion is also proposed. The results indicate that Sr2La8(SiO4)(6)O-2:Ce3+, Tb3+ phosphors have potential applications to be used as near UV-convertible phosphors for white light-emitting diodes because of the broad excitation in the near-ultraviolet range and the efficient green emission light. (C) 2014 Elsevier Inc. All rights reserved.