Enhancement of Multicolor Luminescence of GdVO4 Core-Shell Structure via TiO2 Interlayer

By using sodium citrate as complexing and capping agent, GdVO4 core-shell structures (CSSs) were prepared via hydrothermal method, with Dy3+ and Eu3+ doped into the core and shell layer, respectively. The as-prepared CSSs were then annealed at 600 degrees C for 2 h in muffle furnace. XRD and TEM results show that crystalline phase of the well-dispersed CSSs is tetragonal phase. To avoid interdiffusion of Dy3+ and Eu3+ during annealing process, i.e., to prevent energy transfer from Dy3+ to Eu3+, TiO2 interlayer was inserted between the core and shell layer. The normalized emission spectra at the excitation wavelength of 253 or 340 nm prove that TiO2 interlayer can significantly enhance luminescence of Dy3+ ions. Besides, CIE (x, y) chromaticity coordinate diagram analysis shows that the CSS with TiO2 interlayer provide much better multicolor luminescence performance than other materials. The experimental scheme presented in the context provides a feasible way to find high-quality phosphors for UV-excitated white light-emitting diod (WLED).