Synthesis and upconversion properties of Ln3+ doped YOF nanofibers

Nanofibers of YOF doped with trivalent lanthanide ions (Ln3+) have been synthesized successfully via an electrospinning method combining with high-temperature calcination in air. Scanning electron microscopy (SEM) observations showed that the nanofibers had uniform one-dimensional (1D) morphology. X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM) images revealed that the calcined fibers were constituted by rhombohedral phase yttrium oxyfluoride nanocrystals. Under the excitation from a 980 nm laser diode, YOF:Yb3+,Tm3+ and YOF:Yb3+,Er3+ fibers emitted blue and red light, respectively. Upconversion mechanisms of these YOF:Ln3+ fibers were also discussed in detail.