Tunable multicolor luminescence and white light emission realized in Eu3+ mono-activated GdF3 nanofibers with paramagnetic performance

Abstract

Luminescent–magnetic bifunctional GdF₃:Eu³⁺ nanofibers have been successfully fabricated via the combination of electrospinning followed by calcination with fluorination technique. The structure, morphologies, luminescence, and magnetic properties of the synthesized nanomaterials have been characterized by a variety of techniques. X-ray diffraction (XRD) analysis indicates that the as-obtained GdF₃:Eu³⁺ nanofibers have a pure orthorhombic structure. Scanning electron microscope (SEM) observations show that the directly electrospinning-made PVP/[Gd(NO₃)₃ + Eu(NO₃)₃] composite nanofibers have smooth surfaces, uniform size and good dispersion, and the surfaces of GdF₃:Eu³⁺ nanofibers become rough after calcination and fluorination process. The diameters of composite nanofibers and GdF₃:Eu³⁺ nanofibers are respectively 333.26 ± 1.80 nm and 86.54 ± 0.55 nm under the confidence level of 95%. Under 274 nm ultraviolet light excitation, GdF₃:Eu³⁺ nanofibers exhibit characteristic ⁵D_3,2,1,0 → ⁷F_J emission of Eu³⁺ and the trend of their color tones changes from blue, cold white, warm white to red by adjusting the molar concentration of Eu³⁺. In addition, all of the samples exhibit paramagnetic features and the magnetic properties of GdF₃:Eu³⁺ nanofibers are tunable by modulating the doping concentration of Eu³⁺ ions. More importantly, the tunable multicolor luminescence, white light emission and paramagnetic properties are simultaneously realized in single-phase GdF₃:Eu³⁺ nanofibers, which are ideally suited to applications in many fields such as solid-state lasers, lighting and displays, magnetic resonance imaging. This design conception and construction strategy developed in this work may provide some new guidance for the synthesis of other rare earth fluoride nanostructures with various morphologies.