Abstract: Rare earth Tb³⁺ doped gadolinium phosphate (GdPO₄) green phosphor is a potential phosphor for white LED, while the preparation by conventional hydrothermal method has some problems, such as long reaction time and low doping amount of Tb³⁺. A series of Gd_1-xPO₄∶xTb³⁺ (x=0, 1%, 5%, 11%, 13%, 15%, 17%, 19%) samples were prepared by hydrothermal method combined with high temperature sintering. The phase structure, morphology, elemental composition, optical absorption and luminescence properties of samples were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM)-energy spectrometer (EDS), infrared spectrometer (FT-IR) and fluorescence spectrophotometer. The results show that, all the synthesized samples are pure phase of GdPO₄ belonging to monoclinic monazite structure, and the Tb³⁺ are uniformly distributed in GdPO₄ matrix and cause lattice shrinkage. Under 274 nm photoexcitation, GdPO₄∶Tb³⁺ phosphors have the strongest emission peak at 545 nm, which belongs to ⁵D₄→⁷F₅ transition of Tb³⁺. The fluorescence quenching concentration of Tb³⁺ was determined to be 15% (molar ratio), and this sample (GdPO₄∶15%Tb³⁺) exhibits excellent green light emission and good thermal stability.

Key words: gadolinium phosphate, Tb³⁺ doping, hydrothermal method, high temperature sintering, luminescent property, green phosphor