Host-sensitized emission of LiInW2O8 wolframites: From red-Eu to white-Dy phosphors

The LiInW₂O₈:Eu³⁺, LiInW₂O₈:Dy³⁺ and LiInW₂O₈:Eu³⁺/Dy³⁺ phosphors were synthesized by solid-state reaction and their photoluminescence properties were studied. Under UV excitation, the LiInW₂O₈:Eu³⁺ phosphor exhibits an intense red emission whereas the LiInW₂O₈:Dy³⁺ and LiInW₂O₈:Dy³⁺/Eu³⁺ phosphors show a white emission. The WO₆ octahedra play a major role in the luminescence of the host lattice, characterized by a blue emission under UV excitation. The emission of activator ion results from an efficient energy transfer from the LiInW₂O₈ host lattice to the Eu³⁺ and Dy³⁺ ions. The LiIn_0.97Dy³⁺_0.03W₂O₈ and LiIn_0.965 Dy³⁺_0.03Eu³⁺_0.005W₂O₈ samples, optimized for white emission, are interesting candidates for solid-state lighting applications.