Characterization of ZnGa2O4:Mn2+ nanophosphor synthesized by the solvothermal method in 1,4-butanediol–water system

We characterized ZnGa2O4:Mn2+ (ZnGa2O4—zinc gallate) nanophosphor synthesized by the solvothermal method in 1,4-butanediol-containing water to increase the amount of Mn2+ ions incorporated in the ZnGa2O4 matrix without post-heat treatment. We investigated the influence of water content in the solvent on the photoluminescence (PL) intensity and the Mn amount, the latter being measured by X-ray fluorescence analysis and electron paramagnetic resonance spectroscopy. The PL intensity per Mn amount reached the maximum at the 50 wt% water content. The addition of water promotes repeated dissolution and precipitation, resulting in homogeneous Mn2+ distribution in the ZnGa2O4 matrix. This suggests that the solvothermal method in the 1,4-butanediol–water system is useful for increasing the amount of Mn2+ ions incorporated in the ZnGa2O4 matrix without post-heat treatment. At the water content >50 wt%, the decrease in PL intensity is attributed to the optical absorption of the by-product, MnOOH.