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

Abstract

In the Li 2 OTa 2 O 5 TiO 2 system, Li 1+x¹y Ta 1¹x¹3y Ti x+4y O 3 (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 Mn 4+ ion. The phosphor emitted at around 685 nm excited by 493 nm. The photoluminescence (PL) intensity closely related to the ratio of Mn 4+ /Mn 3+ 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.