Synthesis and upconversion luminescence properties of YF3:Yb3+/Er3+ hollow nanofibers derived from Y2O3:Yb3+/Er3+ hollow nanofibers

YF3: Yb3+/Er3+ hollow nanofibers were successfully fabricated via fluorination of the relevant Y2O3: Yb 3?/Er3+ hollow nanofibers whichwere obtained by calcining the electrospun PVP/[Y(NO3) 3 ? Yb (NO3)(3) ? Er(NO3)(3)] composite nanofibers. The morphology and properties of the products were investigated in detail by X- ray diffraction, scanning electron microscope, transmission electron microscope, and fluorescence spectrometer. YF3: Yb-3+/Er-3? hollow nanofibers were pure orthorhombic phase with space group Pnma and were hollow- centered structure with mean diameter of 174 +/- 22 nm, and YF3: Yb3+/Er3+ hollow nanofibers are composed of nanoparticles with size in the range of 30-60 nm. Upconversion emission spectrum analysis manifested that YF3: Yb 3+/Er3+ hollow nanofibers emitted strong green and weak red upconversion emissions centering at 523, 545, and 654 nm, respectively. The green and red emissions were, respectively, originated from H-2(11/2)/(4) S-3/2 -> I-4(15/2) and F-4(9/2)+-> (4)Il(5/2) energy levels transitions of theEr 3? ions. Moreover, the emitting colors of YF3: Yb3+/Er3+ hollow nanofibers were located in the green region in CIE chromaticity coordinates diagram. This preparation technique could be applied to prepare other rare earth fluoride upconversion luminescence hollow nanofibers.