The role of excess MgO in the intensity increase of red emission of Mn4+-activated Mg2TiO4 phosphors

• Published in: Journal of materials science. Materials in electronics Vol. 31; no. 10; pp. 7555 - 7564
• Main Authors: Borkovska, L., Khomenkova, L., Vorona, I., Nosenko, V., Stara, T., Gudymenko, O., Kladko, V., Labbé, C., Cardin, J., Kryvko, A., Kryshtab, T.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2020; Springer Nature B.V; Springer Verlag
• Subjects: Characterization and Evaluation of Materials; Chemical Sciences; Chemistry and Materials Science; Computational Physics; Condensed Matter; Crystal lattices; Efficiency; Electromagnetism; Electron paramagnetic resonance; Emission spectra; Engineering Sciences; Fluorides; Investigations; Light emitting diodes; Luminescence quenching; Magnesium; Magnesium oxide; Manganese ions; Material chemistry; Materials; Materials Science; Micro and nanotechnologies; Microelectronics; Optical and Electronic Materials; Optics; Phosphors; Photoluminescence; Photonic; Physics; Semiconductors; Sintering; Superconductors (materials); Synthesis; Titanium dioxide
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-020-03143-x

The influence of magnesium oxide (MgO) content on the intensity of red photoluminescence (PL) of Mn 4+ ions in Mn-doped phosphors Mg 2 TiO 4 :Mn produced by solid-state reaction at 1200 °C has been investigated by PL, optical absorption, X-ray diffraction, and electron paramagnetic resonance methods. The phosphors synthesized with excess MgO show an increase of Mn 4+ red emission compared with those of stoichiometric composition. The magnitude of this increase depends on both MgO and Mn content. The largest increase of PL intensity is found for the phosphors synthesized under 3:1 molar ratios of MgO to TiO 2 . For these phosphors, the PL intensity increases from time 1.1 to time 3 when Mn concentration decreases from 1.0 to 0.0001 mol%. The phosphors produced under 6:1 molar ratios demonstrate a decrease of PL intensity at any Mn concentration. It is shown that excess MgO promotes stabilization of Mg 2 TiO 4 phase against decomposition, hinders formation of Mn 2+ centers, and enhances Mn 4+ ions incorporation in the Mg 2 TiO 4 crystal lattice. The latter together with reduced concentration quenching are supposed to be the main reasons of PL enhancement, which leads to the conclusion that excess MgO is necessary to produce an efficient red phosphor.