Preparation, morphology and luminescence properties of Gd₂O₂S:Tb with different Gd₂O₃ raw materials

The sulfide fusion method was used to synthesize Gd₂O₂S:Tb phosphors using commercial Gd₂O₃ and freshly prepared Gd₂O₃, respectively. The freshly prepared Gd₂O₃ was synthesized from Gd₂O(CO₃)₂·H₂O precursor prepared by homogeneous precipitation method. The structure and morphology of the composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The result shows that the Gd₂O₂S:Tb phosphor prepared by commercial Gd₂O₃ (GOST-A) presents agglomerated particles with average particle size of 2.1 µm; however, Gd₂O₂S:Tb produced from as-prepared Gd₂O₃ (GOST-B) tends to form regular hexagon particles with the average particle size of 1 µm. Furthermore, Gd³⁺ and Tb³⁺ contents in GOST-B are higher than that in GOST-A. In addition, fluorescent properties were analyzed by fluorescent spectrophotometer. It is indicated that similar excitation and emission spectra can be obtained from the two phosphors, but the luminescence intensity of GOST-B is higher than that of GOST-A.