Luminescence properties and efficient energy transfer in Ce3+ and Tb3+ co-doped Mg2La3[SiO4]2[PO4]O phosphor

A series of Ce3+, Tb3+ singly doped and Ce3+/Tb3+-co-doped Mg2La3[SiO4]2[PO4]O phosphors with the apatite-like structure were prepared by conventional solid-state reaction. The X-ray diffraction (XRD), photoluminescence excitation and emission spectra, luminescence decay curves and lifetimes were applied to characterize the samples. The efficient excitation energy transfer from Ce3+ to Tb3+ was verified by the excitation and emission spectra together with the luminescence decay curves. The Ce3+/Tb3+ co-doped phosphor shows an intense broad excitation band between 300 and 430 nm, which matches near-UV chip (350–420 nm). Under the excitation of near UV light, the Ce3+/Tb3+ co-doped sample exhibits two distinct luminescence bands: a blue one centered at about 415 nm originating from Ce3+ ions and a green-emitting at 543 nm from the 5D4→7F5 transition of Tb3+ ions. The emission can be tuned from the blue to the green color by changing the doping concentration of Tb3+. The energy transfer from Ce3+ to Tb3+ has been demonstrated to be the dipole–quadrupole mechanism, and the critical distance is calculated to be 16.04 Å.