Synthesis and Luminescence Properties of YNbO 4 :A (A = Eu 3+ and/or Tb 3+ ) Nanocrystalline Phosphors via a Sol–Gel Process

Rare-earth (Eu 3+ and/or Tb 3+ ) ions doped YNbO 4 phosphors were prepared though a Pechini-type sol–gel 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 °C and pure YNbO 4 phase can be obtained at 1000 °C. FE-SEM images indicate that the YNbO 4:A (A = Eu 3+ and/or Tb 3+ ) samples consist of fine and spherical grains of around 40–80 nm. Under the ultraviolet light (around 255 nm) and low-voltage electron beams, the prepared YNbO 4:A (A = Eu 3+ and/or Tb 3+ ) phosphors show the characteristic blue broadband emission (from 300 to 500 nm with a maximum around 403 nm) of the YNbO 4 host lattice, the characteristic red emission of Eu 3+ ( 5 D J → 7 F J ′, J, J ′ = 0,1,2,3 transitions) and the characteristic green emission of Tb 3+ ( 5 D 4 → 7 F 6,5,4,3 transitions). There exists an energy transfer from the YNbO 4 host lattices to Eu 3+ (Tb 3+ ) ions. By tuning the relative doping concentration of Eu 3+ and Tb 3+, a single-composition white-light-emitting has been realized in YNbO 4:Eu 3+,Tb 3+ phosphor. The obtained YNbO 4:Eu 3+, YNbO 4:Tb 3+, and YNbO 4:Eu 3+,Tb 3+ phosphors have potential application in the areas of UV white-light-emitting diodes, field emission display devices, and vacuum fluorescent display devices, etc.