Characterization and optical properties of ZnGa2O4:Eu3+ nanophosphor grown by hydrothermal method

ZnGa2O4 phosphor doped with Eu3+ ions was synthesized by hydrothermal method using two concentrations: 3.34 mol% and 1.67 mol% of Eu3+. The crystal structure was investigated by means of X-ray diffraction, scanning electron microscopy and atomic force microscopy. The results indicate that the material consisting of ZnGa2O4:Eu3+ nanoparticles exhibits good crystalinity, with cubic spinel structure. The powders were found to have 4.74 eV of ZnGa2O4:Eu3+ (3.34 mol%) and 4.69 eV of ZnGa2O4:Eu3+ (1.67 mol%) band gaps, respectively. The luminescent analysis of the materials shows that the trivalent europium ions doped in this material are localized in different sites, substituting both Zn2+ and Ga3+. The emission spectra of the europium-doped samples, originating from 5D0–7FJ (J = 0–4) transitions, suggests the existence of three different site symmetry of Eu3+ ions, tetrahedral (Zn2+), distorted octahedral (Ga3+) and low octahedral (Ga3+) sites, respectively.