Hydrothermal synthesis of α-Zn<inf>2</inf>SiO<inf>4</inf>:V phosphor, determination of oxidation states and structural localization of vanadium ions

© 2016 Elsevier LtdThe monophase morphologically homogeneous phosphor α-Zn2SiO4:V has been produced by the hydrothermal method. With the use of energy-dispersive analysis and X-ray powder diffraction analysis, it was established that the ratio of cations Zn:Si:V corresponded to the formula Zn2Si0.9V0.1O4. The charge state of vanadium ions was determined by the spectroscopic methods. Maxima of the bands in the luminescence spectra correspond to V5+ (523 nm) and V3+ (720 nm) centers. The small width of the EPR signal hyperfine structure components indicates the presence of single V4+ centers, their contribution is not greater than 0.1% of the total vanadium content. The presence of a broad structureless component in the EPR spectrum was explained by the fact that the main amount of the dopant ion was united in the areas containing V5+, V4+ and V3+ ions. V4+ ions and V5+ ions with high probability occupy silicon positions in the lattice