Host-Sensitized and Tunable Luminescence of GdNbO:Ln (Ln = Eu/Tb/Tm) Nanocrystalline Phosphors with Abundant Color.

Up to now, GdNbO has always been regarded as an essentially inert material in the visible region with excitation of UV light and electron beams. Nevertheless, here we demonstrate a new recreating blue emission of GdNbO nanocrystalline phosphors with a quantum efficiency of 41.6% and host sensitized luminescence in GdNbO:Ln (Ln = Eu/Tb/Tm) nanocrystalline phosphors with abundant color in response to UV light and electron beams. The GdNbO and GdNbO:Ln (Ln = Eu/Tb/Tm) nanocrystalline phosphors were synthesized by a Pechini-type sol-gel process. With excitation of UV light and low-voltage electron beams, the obtained GdNbO nanocrystalline phosphor presents a strong blue luminescence from 280 to 650 nm centered around 440 nm, and the GdNbO:Ln nanocrystalline phosphors show both host emission and respective emission lines derived from the characterize f-f transitions of the doping Eu, Tb, and Tm ions. The luminescence color of GdNbO:Ln nanocrystalline phosphors can be tuned from blue to green, red, blue-green, orange, pinkish, white, etc. by varying the doping species, concentration, and relative ratio of the codoping rare earth ions in GdNbO host lattice. A single-phase white-light-emission has been realized in Eu/Tb/Tm triply doped GdNbO nanocrystalline phosphors. The luminescence properties and mechanisms of GdNbO and GdNbO:Ln (Ln = Eu/Tb/Tm) are updated.