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

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