Synthesis and luminescence properties of Sr3(VO4)2:Eu3+ phosphor and emission enhancement by co-doping Li+ ion

Sr3(VO4)2:Eu3+ and Sr3(VO4)2:Eu3+, Li+ phosphors are synthesized by solid-state reaction method in air. X-ray diffraction patterns indicate that all samples are pure phase Sr3(VO4)2. The host Sr3(VO4)2 with excitation 348 nm emits yellow-green light. Emission spectrum of Sr3(VO4)2:Eu3+ phosphor with excitation 335 nm contains a broad emission band peaking at ∼540 nm due to V5+ → O2− charge transfer and some narrow emission bands owing to the 4f – 4f electron transations of Eu3+ ion in the range of 400–780 nm. With excitation 394 nm, only emision bands derived from Eu3+ ion are observed. Emission intensity of Sr3(VO4)2:Eu3+ phosphor can be improved obviously due to charge compensation and fluxing agent role of Li+ ion when Li+ ion is co-doped. The optimal Eu3+ doping concentration is ∼5 mol%. The energy transfer process between [VO4]3− group and Eu3+ ion is observed and analyzed by emission spectrum in Sr3(VO4)2:Eu3+ phosphor. The luminous mechanism of Sr3(VO4)2:Eu3+ phosphor is explained by energy transfer and energy level diagram of [VO4]3− group and Eu3+ ion.