Red-Shifted Absorption of a Mn4+-Doped Germanate Phosphor by Crystal Distortion

摘要

A Mn4+-doped germanate red-emitting phosphor, in which TiO2 is partially substituted for GeO2, was synthesized by a solid-state reaction. The proportional composition of the compound was 3.5MgO-Ge1-xTixO2-0.5MgF(2): Mn4+. The main X-ray diffraction peak exhibited a gradual shift to lower angles depending on the synthesis temperature and the extent of Ti substitution. Substitution of GeO2 with TiO2 yielded a redshift of the broad excitation band (380-500 nm), which resulted from the (4)A(2) - T-4(2) transition of Mn4+. Compared with the sample containing only GeO2, the relative luminescence of the sample in which GeO2 was partially replaced with TiO2 was increased by 19.3% for excitation at 450 nm. (c) The Author(s) 2017. Published by ECS. All rights reserved.