Crystal structure, luminescence properties and energy transfer of Eu 3+ /Dy 3+ doped GdNbTiO 6 broad band excited phosphors

GdNbTiO 6 is used as a host material for phosphors for the first time. Lanthanide ion (Eu 3+ /Dy 3+ ) doped GdNbTiO 6 phosphors were prepared by solid-state reaction, and the crystal structure, luminescence properties, and relevant luminescence mechanisms were investigated. The crystal structure of Eu 3+ /Dy 3+ doped GdNbTiO 6 was refined from powder XRD data by the Rietveld method, which is made up of irregular (Gd/Eu/Dy) 3+ O 8 13− polyhedra and slightly distorted Nb(Ti)O 6 octahedra forming a layered structure. The luminescence properties of the GdNbTiO 6 :Eu 3+ /Dy 3+ phosphors were studied under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation. The GdNbTiO 6 host shows a broad emission band about the 400–650 nm region centered at 509 nm owing to the Nb(Ti)O 6 octahedral groups, which has spectral overlap with f–f excitation transitions of Eu 3+ /Dy 3+ in the doped samples. For red phosphor GdNbTiO 6 :Eu 3+ , a dominant emission peak at 614 nm was attributed to the 5 D 0 → 7 F 2 transition of Eu 3+ , which confirmed that Eu 3+ ions are located at sites without inversion symmetry. The phosphor GdNbTiO 6 :Dy 3+ shows bright yellow-green emission prevailing at 577 nm upon 273 nm excitation. With increasing activator concentration, the emission derived from the characteristic f–f transitions of Eu 3+ /Dy 3+ is enhanced while the host emission is weakened, which is due to the energy transfer from the host to Eu 3+ /Dy 3+ . Considering the facile synthesis and excellent Eu 3+ /Dy 3+ doped luminescence properties of this compound, self-activated GdNbTiO 6 may be a good candidate as a host phosphor for use in various optical devices.