Hydrothermal synthesis and luminescence properties of YW 2O 6(OH) 3:Tb 3+ green phosphors

YW2O6(OH)3:Tb3+ green phosphors were synthesized at different pH values via a facile hydrothermal method. The structure and optical properties of as-synthesized samples were studied by X-ray diffractometer (XRD), scanning electron microscopy (SEM), photoluminescence spectra and luminescence decay curve. The results showed that pure monoclinic YW2O6(OH)3:Tb3+ green phosphors could be obtained at pH 2–5. Uniform spherical micro-phosphors of ∼5 μm in diameter with narrow size distribution could be prepared at pH 5. pH value had dramatic influence on morphologies, which could be ascribed to the various spatial configurations of different poly-tungstates existing at different pH values. The emission spectra under 261 nm excitation exhibited dominant green emission at 546 nm. The green emission intensity reached the maximum value at pH 5 due to the high packing density of the obtained phosphor.