Preparation And Characterization Of Rare Earth Doping YAG Phosphors And Y-TZP Nanopowder

In the present paper, a novel way named polyacrylamide gel method was employed to synthesize the rare earth doping YAG (yttrium aluminum garnet, Y₃Al₅O₁₂) nano-sized YAG: Eu³⁺, YAG: Ce³⁺ and YAG: Tb³⁺ phosphors at low temperature, respectively. Effects of the heating temperature and the doping concentration of the YAG nano-sized phosphor were evaluated. MOCVD (metal organic chemical vapor deposition) method was employed to prepare YAG: Eu³⁺ phosphors. Moreover, polyacrylamide gel method was employed to prepare Y-TZP (tetragonal zirconia polycrystals stabilized by Y₂O₃) nano-sized powder. The results and development are as follows:1. The rare earth element doping YAG nano-sized phosphors was prepared at a lower temperature by using polyacrylamide gel method. XRD and TG-DTA analyses demonstrated that YAP (YAlO₃) phase was observed at 800℃, and quickly converted to YAG phase with the heating temperature increased, phase-pure YAG was observed at 850℃. XRD and SEM analysis indicated the phosphor powders grain size increased and luminescence intensity enhanced with the rising heating temperature, but powders were well dispersed and still in nano-scale. Concentration quenching phenomenon appeared after the doping concentration of ions (Eu³⁺, Ce³⁺, Tb³⁺) into YAG lattices reaching a certain extent. The blue-shift in the spectra of ultrafine YAG: Eu³⁺ and YAG: Ce³⁺ phosphors powder was observed. Furthermore, we discussed the luminescence mechanism of YAG with the luminescence center.2. MOCVD method was employed to prepare the YAG: Eu³⁺ phosphor. RD, SEM and fluorescence spectrium characterizion indicated that the particles as prepared looked almost spherical with a mean diameter of about 1μm. The classic absorption and emission spectra of YAG: Eu³⁺ phosphor were clearly observed.3. The nano-sized Y-TZP powder was prepared at a lower temperature by using polyacrylamide gel method. The samples were characterized by XRD, SEM and fluorescence spectrometer. Results showed that the yttrium doping tetragonal phase nano-sized zirconia comprised Al₂O₃ appeared at 600℃, while slightly sintering and weak luminescence phenomenon were observed at 1 000℃.