不同氣氛控制下所合成之 (Y1-xTbx)3Al5O12 固溶體的晶體結構與螢光性質

This study uses pH controlling to make the reactant well mixed and dispersed, and synthesizes (Y1-xTbx)3Al5O12 solid-solution with solid-state reaction in different atmosphere, discussing the relationships of crystal structure and fluorescence property. The first part synthesizes (Y1-xTbx)3Al5O12 solid-solution in air without ventilation, discussing the internal crystal structure changes from YAG to TAG, fluorescence property, and the influence of terbium concentration increased on the ion valence. Due to the Tb3+ is easy to lose one electron, the system would have both the Tb3+ and Tb4+. After 1600oC/ 16 h heat treatment, the pure phase of (Y1-xTbx)3Al5O12 solid-solution will be synthesized. The crystal structure is getting stable as the terbium concentration increases, so the valence of terbium will stabilize trivalence. The second part tries to synthesize (Y1-xTbx)3Al5O12 solid-solution by the different atmosphere controlling. Then compare with their crystal structure and fluorescence property. The pure phase of (Y1-xTbx)3Al5O12 solid-solution can be obtained after 1600oC/16 h heat treatment. The study shows that from the absorption spectrum, the intensity of PL spectrum, and the binding energy in ESCA can determine the Tb4+ content. If the system has more Tb4+, it will influence the cell parameters by terbium substituting yttrium. And it would be observed the different fluorescence effect in Raman spectrum. Furthermore, the Tb4+ substitutes the Y3+ would generate the vacancies to help the grain growth.