Tunable Luminescence and Energy Transfer properties of Sr3AlO4F: RE3+ (RE = Tm/Tb, Eu, Ce) Phosphors

Sr3AlO4F:RE3+ (RE = Tm/Tb, Eu, Cc) phosphors were prepared by the conventional solid-state reaction. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), photoluminescence (PL) spectra, as well as lifetimes were utilized to characterize samples. Under the excitation of UV light, Sr3AlO4F:Tm3+, Sr3AlO4F:Tb3+, and Sr3AlO4F:Eu3+ exhibit the characteristic emissions of Tm3+ (D-1(2)-> F-3(4), blue), Tb3+ (D-5(4)-> E-7(5), green), and Eu3+ (D-5(0)-> F-7(2), red), respectively. By adjusting the doping concentration of Eu3+ ions in Sr3AlO4F:0.10Tm(3+), 0.10Tb(3+), zEu(3+), a white emission in a single composition was obtained under the excitation of 360 nm, in which an energy transfer from Tb3+ to Eu3+ was observed. For Sr3AlO4F:Ce3+,Tb3+ samples, the energy transfer from Ce3+ to Tb3+ is efficient and demonstrated to be a resonant type via a dipole-quadrupole interaction by comparing the experimental data and theoretical calculation. Furthermore, the critical distance of the Ce3+ and Tb3+ ions has also been calculated to be 9.05 angstrom. The corresponding luminescence and energy transfer mechanisms have been proposed in detail. These phosphors might be promising for use in near-UV LEDs.