Tunable emission, energy transfer and charge compensation in Sr3(VO4)2:Sm(3+),P(5+),Na(+) phosphor

A series of Sr3(VO4)2:Sm(3+),P(5+),Na(+) phosphors are synthesized by using solid-state reaction method in air. The strongest emission band peaking at ∼600 nm is assigned to the (4)G5/2→(6)H7/2 transition of Sm(3+) ion, and the strong excitation peak at ∼402 nm due to (6)H5/2→(4)F7/2 transition indicates that these phosphors can be excited by near ultraviolet light emitting diode chip. Energy transfer (ET) between VO4(3-) group and Sm(3+) ion can be observed. Sr3(VO4)2:Sm(3+) phosphor with excitation 320 nm exhibits a systematically varied hues from green to yellow by changing Sm(3+) ion concentration from 0 to 6 mol%. The luminous mechanism of Sr3(VO4)2:Sm(3+) phosphor is explained by using the energy level diagrams of VO4(3-) group and Sm(3+) ion. The luminescence properties of Sr3(VO4)2:Sm(3+) phosphor can be improved and tuned by codoping the P(5+) and Na(+) ions due to ET and charge compensation. Lifetimes of Sr2.925Sm0.05(VO4)2, Sr2.925Sm0.05(V0.9P0.1O4)2, and Sr2.9Na0.05Sm0.05(V0.9P0.1O4)2 phosphors are 1.208, 1.219, and 0.796 ms, respectively. The experiment results are helpful to adjust the luminescence properties of Sm(3+)-doped other phosphors.