Fei Bi

Tuned magnetism–luminescence bifunctionality simultaneously assembled into flexible Janus nanofiber

A new structure of [CoFe2O4/PVP]//[YAG:5%Eu3+/PVP] magnetic–luminescent bifunctional Janus nanofibers has been successfully fabricated via electrospinning technology using a homemade parallel spinneret. Electrospinning-derived YAG:5%Eu3+ luminescent nanofibers and CoFe2O4 magnetic nanofibers are incorporated into polyvinyl pyrrolidone (PVP) matrix and electrospun into Janus nanofibers with CoFe2O4 magnetic nanofibers/PVP as one strand nanofiber and YAG:5%Eu3+ luminescent nanofibers/PVP as another strand nanofiber. [CoFe2O4/PVP]//[YAG:5%Eu3+/PVP] magnetic–luminescent bifunctional Janus nanofibers possess superior magnetic and luminescent properties due to their special nanostructure, and the luminescent characteristics and saturation magnetizations of the Janus nanofibers can be tuned by adding various amounts of YAG:5%Eu3+ luminescent nanofibers and CoFe2O4 magnetic nanofibers. Compared with CoFe2O4/YAG:5%Eu3+/PVP composite nanofibers, the magnetic–luminescent bifunctional Janus nanofibers provide higher performances due to the isolation of YAG:5%Eu3+ luminescent nanofibers from CoFe2O4 magnetic nanofibers. More importantly, the design conception and construction technology are of universal significance to fabricate other bifunctional Janus nanofibers.

Tunable and enhanced simultaneous magnetism-luminescence bifunctionality assembled into a coaxial nanofiber

[CoFe2O4–PVP]@[(Y(NO3)3 + Tb(NO3)3 + Al(NO3)3)–PVP] composite coaxial nanofibers have been successfully fabricated via electrospinning technology using a homemade coaxial spinneret. A new structure of CoFe2O4@YAG:Tb3+ magnetic-luminescent bifunctional coaxial nanofibers is obtained by calcination of the prepared electrospun composite coaxial nanofibers. The morphologies, structures, magnetic and luminescence properties of the final products were investigated in detail by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), fluorescence spectroscopy and vibrating sample magnetometry (VSM). The results show that the CoFe2O4@YAG:7%Tb3+ magnetic-luminescent bifunctional coaxial nanofibers simultaneously possess superior magnetic and luminescence properties due to isolation of the YAG:7%Tb3+ luminescence center from CoFe2O4 magnetic nanofibers. Furthermore, the luminescence intensity, color and saturation magnetization of the coaxial nanofibers can be tuned via adjusting the concentrations of rare earth ions and the amount of CoFe2O4 magnetic nanofibers. The bifunctional magnetic-luminescent CoFe2O4@YAG:7%Tb3+ coaxial nanofibers have potential applications in biomedical areas, such as drug-delivery systems, cell labeling and separation, enhancement for magnetic resonance imaging and subsequent optical identification. More importantly, the design conception and construction technology can fit the elaboration of any other bifunctional coaxial nanofibers.

Electrospinning Preparation and Photoluminescence Properties of Y3Al5O12 :Eu3+ Nanobelts

Novel structures of Y3Al5O12: Eu3+ (denoted as YAG: Eu3+ for short) nanobelts were fabricated by calcination of the electrospun PVP/[Y(NO3)3+Eu(NO3)3+Al(NO3)3] composite nanobelts. X-ray powder diffraction (XRD) analysis showed that YAG: Eu3+ nanobelts were cubic in structure with space group Ia3d. Fourier transform infrared spectroscopy (FTIR) analysis manifested that pure YAG: Eu3+ nanobelts were formed at 900 °C. Scanning electron microscope (SEM) analysis indicated that the YAG: Eu3+ nanobelts have coarse surface. The width and thickness of YAG: Eu3+ nanobelts were ca. 3.25 µm and ca. 220 nm, respectively. Fluorescence spectra analysis revealed that YAG: Eu3+ nanobelts emitted the main strong emission centering at 592 nm under the ultraviolet excitation of 235 nm, which was attributed to 5D0→7F1 of Eu3+, and the optimum doping molar concentration of Eu3+ ions was 5%. CIE analysis demonstrated that the emitting colors of YAG: Eu3+ nanobelts could be tuned by adjusting doping concentration of Eu3+. The possible formation mechanism of YAG: Eu3+ nanobelts was also proposed.

Facile Electrospinning Preparation of Y3Al5O12 Nanobelts

PVP/[Y(NO3)3+Al (NO3)3] composite nanobelts were fabricated via electrospinning combined with sol-gel process and novel structure of Y3Al5O12 (denoted as YAG for short) nanobelts have been obtained after calcination of the relevant composite nanobelts. The structural properties were characterized by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). XRD analysis indicated that the composite nanobelts were amorphous, and YAG nanobelts were cubic in structure with space group Ia3d. FTIR analysis manifested that pure YAG nanobelts were formed at 900oC. SEM analysis and histograms revealed that the width of the composite nanobelts and YAG nanobelts were 3.5 μm and 2.4 μm, and the thickness were 240 nm and 112 nm, respectively, under the 95% confidence level. The formation mechanism of YAG nanobelts was discussed in detail.