Luminescence properties and energy transfer in La6Ba4(SiO4)6F2:Ce3+,Tb3+ phosphors

A series of new luminescent emission-tunable phosphors La6Ba4(SiO4)6F2:Ce3+,Tb3+ with apatite structure have been synthesized by a high temperature solid-state reaction. X-ray diffraction, photoluminescence (PL) emission and excitation spectra, lifetime, as well as the effect of Tb3+ concentration were employed to characterize the resulting samples. The PL spectrum of La6Ba4(SiO4)6F2:Ce3+,Tb3+ phosphor contains both the asymmetric broad-band blue emission (Ce3+ ion) and the line-type green emission (Tb3+ ion). The increased Tb3+ concentration induced the emitting colors to shift from blue to green region by the naked eye. Meanwhile, the energy transfer between Ce3+ and Tb3+ is thoroughly investigated, and the energy-transfer efficiency from Ce3+ to Tb3+ ion is also calculated. The results indicated that these phosphors could be considered as double emission phosphors for n-UV excited white light-emitting diodes.