Study On The Preparation Techniques Of Gadolinium Oxysulfide Powder Doped With Rare Earth

Rare earth oxysulfide?RE₂O₂S?is an important optical functional material with hexagonal crystal structure.Among them,gadolinium oxysulfide?Gd2O2S?owns good chemical stability and thermal stability which make Gd2O2S be a potential luminescent matrix material.Pr³⁺ions and Tb³⁺ions doped Gd₂O₂S show important applications in high resolution computer tomography detector display and intensifying screen.In this thesis,a series of rare earth doped gadolinium oxysulfide were synthesized by co-precipitation and flux fusion method.The prepared powder was analyzed.The research contents are as follows:?1?The precursor was prepared by co-precipitation method,and the thermogravimetry-differential scanning calorimetry analysis was carryed out to determine the crystal transition temperature of the precursor.The structure and morphology of the precursor were characterized by X-ray diffraction and scanning electron microscopy.The Gd2O2S powder was prepared by high temperature calcining by flux fusion method.The Gd2O2S powder prepared at different calcining temperatures and holding time was tested by X-ray diffraction and scanning electron microscope,and the influence of different calcining temperatures and holding time on the crystal formation process was analyzed.The results showed that the optimal crystal structure could be obtained at 1250?for 2 h calcining,and the particle size of the prepared powder was about 2-5?m.The luminescence performance of Gd₂O₂S:Pr³⁺powder was systematically studied.Under the excitation of313 nm ultraviolet light,the main emission peak was 512 nm.The optimal doping concentration of Pr³⁺ions and the quenching mechanism were discussed.?2?Gd₂O₂S:Tb³⁺powder was prepared.Based on the analysis of the structure and morphology of Gd₂O₂S:Tb³⁺powder,the luminescence performance of the prepared powder was studied by excitation spectrum and emission spectrum analysis.Under the excitation of 292 nm ultraviolet light,the main emission peak was 544 nm,and the influence of the doping concentration of Tb³⁺ions on the luminescence performance was studied,and the quenching mechanism of Tb³⁺ion concentration was discussed in detail.?3?Gd₂O₂S:Tb³⁺,Pr³⁺co-doped powders were prepared,and the luminescence properties of Gd₂O₂S:Tb³⁺,Pr³⁺co-doped powders were studied.The energy transfer mechanism between Tb³⁺-Pr³⁺was analyzed.The energy transfer efficiency between Tb³⁺-Pr³⁺was calculated by the fluorescence lifetime,and the machanism of the energy transfer was finally confirmed as dipole-dipole reaction.Gd₂O₂S:Tb³⁺,Pr³⁺co-doped powders exhibit good green light emission under ultraviolet excitation,and the prepared rare earth doped gadolinium oxysulfide powder has potential application value in the field of computed tomography.