The photoluminescence (PL) intensity of MgGa2O 4:Mn2+ (MGM) nanophosphors synthesized by glycothermal reaction are ∼75 times higher than that of ZnGa2O 4:Mn2+ (ZGM) nanophosphors. We discuss this reason from the following points of view: (i) Mn contents, (ii) particle size, (iii) crystallinity, (iv) spontaneous pressure, (v) emission mechanism, and (vi) Mn2+ state. Judging from the results of the X-ray fluorescence analysis, transmission electron microscopy, X-ray diffractometry, PL spectroscopy, and electron paramagnetic resonance spectroscopy, the more homogeneous distribution of Mn2+ ions in the matrix of MGM is the predominant factor for determining the PL intensity. Mn2+ ions are more homogeneously incorporated into ZGM after post-heat-treatment at 1200°C for 1 h in Ar in comparison to MGM. This is explained by the geometrical reason: the order of ionic radius for tetrahedral coordination is Mg 2+ (71 pm) < Zn2+ (74 pm) < Mn2+ (80 pm). These results indicate that the glycothermal reaction promotes the incorporation of Mn2+ in MGM nanosphosphor, resulting in the higher PL intensity of MGM than that of ZGM. This is attributed to the formation of the low-crystallized MGM glycoxide precursor with the higher homogeneous mixture of different metallic ions.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry