Synthesis and Luminescence Properties of YTaO4:RE3+ (RE = Eu, Dy) Phosphors

YTaO4:RE3+ (RE = Eu or Dy) phosphor powders with different concentrations of activator ions were prepared using the solid-state reaction method. The effects of the concentration of activator ions on the structural, morphological, and photoluminescent properties of the yttrium tantalate phosphors were investigated. The XRD patterns demonstrated that the synthesized phosphors had two mixed phases of YTaO4 and YTa7O19. The size and shape of the crystalline particles were estimated using scanning electron microscopy, and the particles showed a tendency to agglomerate. The emission spectra of the Eu3+-doped YTaO4 phosphors under excitation at 398 nm were composed of an intense red band at 615 nm and three weak bands centered at 596, 653, and 709 nm, respectively, indicating that most Eu3+ ions in the YTaO4 host lattice occupied sites without inversion symmetry. The intensities of all the emission bands reached maxima for the sample doped with 10 mol% of Eu3+ ions. For the Dy3+-doped YTaO4 phosphors, two major emission bands, one at 484 nm and the other at 580 nm, were observed. The results suggest that intense emission and color tunability can be achieved for the phosphors by doping the host lattice with the appropriate amount and type of rare-earth element.