A novel strategy of fabricating GdOF:Er3+ nanofibers possessing upconversion luminescence and paramagnetic properties: The combination of electrospinning with fluoro-oxidation technique

Abstract Upconversion luminescent-magnetic bifunctional GdOF:Er3+ nanofibers have been successfully acquired by means of the combination of electrospinning and fluoro-oxidation calcination technique for the first time. The products have been certified to be pure rhombohedral phase GdOF on the basis of the structural analysis via X-ray powder diffraction (XRD). Scanning electron microscope (SEM) image shows the morphology of GdOF:Er3+ samples is fibrous and the mean diameter is 88 ± 2 nm. Upconversion emission spectrum analysis manifests that GdOF:Er3+ nanofibers emit green and red upconversion emission centering at 523, 543 and 654 nm, respectively ascribed to the 2H11/2 → 4I15/2, 4S3/2 → 4I15/2, 4F9/2 → 4I15/2 energy-level transitions of Er3+ ions under 980-nm ultrared laser excitation. The molar concentration of Er3+ has a great influence on upconversion luminescent intensity. When the doping concentration of Er3+ is 9%, upconversion luminescent intensity reaches to the maximum. Besides, the emission colors of the products are situated at the green region of the CIE chromaticity coordinates. Moreover, GdOF:Er3+ nanofibers demonstrate paramagnetic properties. More importantly, the upconversion luminescence and paramagnetic properties are simultaneously realized in single-phase GdOF:Er3+ nanofibers through our novel strategy, and the bifunctional nanofiber will possess wide applications. The formation mechanism of GdOF:Er3+ nanofibers is also proposed, which may provide some new guidance to manufacture other rare-earth oxyfiuoride upconversion luminescent-magnetic nanostructures with various morphologies.