Sol-gel preparation of efficient red phosphor Mg2TiO4:Mn~(4+) and XAFS investigation on the substitution of Mn~(4+) for TiTi04

摘要

An efficient red phosphor based on the substitution of Mn~(4+) for Ti~(4+) in the lattice of Mg2TiO4 was prepared through a sol-gel route. The phosphor was characterized by X-ray diffraction (XRD), electron paramagnetic resonance (EPR) and UV-vis spectroscopy and the luminescent properties of the samples with varying Mn~(4+) concentrations were investigated. The photoluminescence of the sol-gel prepared Mg2TiO4:Mn~(4+) phosphor was compared with the corresponding sample prepared via solid-state reaction and the commercial CaAISiNsiEu~(4+). X-ray absorption fine structure (XAFS) Investigation reveals the oxidation state and coordination environment of the Mn ion in the crystal structure of Mg2TiO4 and indicates the substitution of Mn~(4+) for Ti-sites. Moreover, a decrease in lattice parameter was observed with the increase of Mn~(4+) content in Mg2TiO4, further confirming the replacement of Ti~(4+) ions by smaller Mn~(4+) ions in the host lattice.