Luminescent performances of Mn4+ ions during the phase evolution from MgTiO3 to Mg2TiO4

TiO 2−x MgO: 0.1 at% Mn 4+ (1   ≤   x   ≤   2) red phosphors are synthesized through a traditional high temperature solid-state reaction method. The excitation and emission spectra indicate that 700   nm and 660   nm red emission peaks are ascribed to Mn 4+ ions doped in MgTiO 3 and Mg 2 TiO 4 , respectively. The Ti 4+ octahedron is connected in MgTiO 3 by O 2− ions of the octahedrons, while the Ti 4+ octahedron is separated in Mg 2 TiO 4 by Mg 2+ tetrahedron and Mg 2+ octahedron. This results that the quenching concentration is higher in Mg 2 TiO 4 than in MgTiO 3 leading the less luminous centers in MgTiO 3 . Detailed spectroscopic and crystal-field studies of the Mg 2 TiO 4 : Mn 4+ and MgTiO 3 : Mn 4+ is described in the present paper.