Photoluminescence in GdVO4:Bi3+, Eu3+ red phosphor

The doubly doped (Bi³⁺ and Eu³⁺) GdVO₄ powder is synthesized by hydrolyzed colloid reaction (HCR) technique and formation of material is confirmed by XRD measurement. Surface morphology has been studied by SEM measurement and the result shows uniform surface morphology. The average particle size observed by SEM is about 1 7m. The Fritsch particle sizer is used to study the particle size distribution. It distributes from O.15 to 3.57 7m. The small particle size (less than 5 7m) and the narrow particle size distribution, are the necessary requirements of good phosphor material. Photoluminescence result shows a narrow emission line of Eu³⁺ ion (4 nm FWHM) at 618 nm. The Eu³⁺ emission intensity is enhanced by a factor of five with the addition of small amount of Bi³⁺. The emission bands of VO₄^3- and Bi³⁺ partially overlap with the excitation band of Eu³⁺. The process of energy transfer from Bi³⁺ to Eu³⁺ is discussed here. The energy transfer probability is strongly dependent upon the Bi³⁺ and Eu³⁺ concentrations, with a maximum for 0.2 mol % of Bi³⁺ and 3 mol % of Eu³⁺. It drastically decreases for higher concentrations. For photoluminescent applications, the quantum efficiency (QE) of a phosphor material is an important parameter. The QE of GdVO₄:Bi,Eu(0.2,3) is 76%. The GdVO₄:Bi,Eu(0.2,3) material is proposed as an efficient photoluminescent phosphor.