Synthesis of Li–Ta–Ti–O new red phosphors with Mn⁴⁺ as activator and the relationship between photoluminescence intensity and crystal structure

抄録

In the Li₂O–Ta₂O₅–TiO₂ system, Li_1+x−yTa_1−x−3yTi_x+4yO₃ (0.14 ≤ x ≤ 0.175, 0.04 ≤ y ≤ 0.175) forms a superstructure by periodical insertion of an intergrowth layer in a matrix having a trigonal structure. In this study, to apply this unique structure as a host material of phosphor, new phosphors with a red emission color were synthesized by doping Mn⁴⁺ ion. The phosphor emitted at around 685 nm excited by 493 nm. The photoluminescence (PL) intensity closely related to the ratio of Mn⁴⁺/Mn³⁺ ion because the ratio changed by sintering temperature and/or Ti content in the matrix. The relationship between PL intensity and crystal structure was investigated using X-ray diffraction, a transmission electron microscope, and X-ray absorption fine structure.