Synthesis and Luminescence Properties of YNbO4:A (A = Eu3+ and/or Tb3+) Nanocrystalline Phosphors via a Sol-Gel Process

Rare-earth (Eu3+ and/or Tb3+) ions doped YNbO4 phosphors were prepared though a Pechini-type solgel process. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy, photoluminescence, and cathodoluminescence spectra were utilized to characterize the synthesized phosphors. XRD reveal that the samples begin to crystallize at 800 degrees C and pure YNbO4 phase can be obtained at 1000 degrees C. FE-SEM images indicate that the YNbO4:A (A = Eu3+ and/or Tb3+) samples consist of fine and spherical grains of around 4080 nm. Under the ultraviolet light (around 255 nm) and low-voltage electron beams, the prepared YNbO4:A (A = Eu3+ and/or Tb3+) phosphors show the characteristic blue broadband emission (from 300 to 500 nm with a maximum around 403 nm) of the YNbO4 host lattice, the characteristic red emission of Eu3+ (D-5(J) -> 7F(J)', J, J' = 0,1,2,3 transitions) and the characteristic green emission of Tb3+ (5D(4) ? 7F(6,5,4,3) transitions). There exists an energy transfer from the YNbO4 host lattices to Eu3+ (Tb3+) ions. By tuning the relative doping concentration of Eu3+ and Tb3+, a single-composition white-light-emitting has been realized in YNbO4:Eu3+,Tb3+ phosphor. The obtained YNbO4:Eu3+, YNbO4:Tb3+, and YNbO4:Eu3+,Tb3+ phosphors have potential application in the areas of UV white-light-emitting diodes, field emission display devices, and vacuum fluorescent display devices, etc.