A new nanostructure of magnetic-fluorescent bifunctional Janus nanobelts with Fe3O4/PMMA as one half and Tb(BA)3phen/PMMA as the other half has been successfully fabricated by a specially designed parallel spinneret electrospinning technology. The morphology and properties of the final products were investigated in detail by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), biological microscopy (BM), vibrating sample magnetometry (VSM) and fluorescence spectroscopy. The results revealed that the [Fe3O4/PMMA]//[Tb(BA)3phen/PMMA] magnetic-fluorescent bifunctional Janus nanobelts possess superior magnetic and fluorescent properties due to their special nanostructure. Compared with Fe3O4/Tb(BA)3phen/PMMA composite nanobelts, the magnetic-fluorescent bifunctional Janus nanobelts provided better performance. The new magnetic-fluorescent bifunctional Janus nanobelts have potential applications in novel nano-bio-label materials, drug target delivery materials and future nanodevices due to their excellent magnetic-fluorescent properties, flexibility and insolubility. Moreover, the construction technique for the Janus nanobelts is of universal significance for the fabrication of other multifunctional Janus nanobelts.

A new type of flexible Janus nanoribbons array with anisotropic electrical conductivity, magnetism, and photoluminescence has been successfully fabricated by electrospinning technology using a specially designed parallel spinneret. Every single Janus nanoribbon in the array consists of a half side of Fe3O4 nanoparticles/polyaniline/polymethylmethacrylate (PMMA) conductive‐magnetic bifunctionality and the other half side of Tb(BA)3phen/PMMA insulative‐photoluminescent characteristics, and all the Janus nanoribbons are aligned to form array. Owing to the unique nanostructure, the conductance along with the length direction of nanoribbons reaches up to eight orders of magnitude higher than that along with perpendicular direction, which is by far the most excellent conductive anisotropy for anisotropic conductive materials. The Janus nanoribbons array is also simultaneously endowed with magnetic and photoluminescent characteristics. The obtained Janus nanoribbons array will have important applications in the future subminiature electronic equipments owing to its high electrical anisotropy and multifunctionality. Furthermore, the design concept and fabrication technique for the flexible Janus nanoribbons array provide a new and facile approach for the preparation of anisotropic conductive films with multifunctionality.

Tm(3+), Dy(3+), and Eu(3+) codoped NaGd(WO4)2 phosphors were prepared by a facile hydrothermal process; they were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectrometer (EDS), photoluminescence spectra, and fluorescence lifetime. The results show that the novel octahedral microcrystals with a mean side length of 2 μm are obtained. Under the excitation of ultraviolet, individual RE(3+) ion (Tm(3+), Dy(3+), and Eu(3+)) activated NaGd(WO4)2 phosphors exhibit excellent emission properties in their respective regions. Moreover, when codoping Dy(3+) and Eu(3+)/Tm(3+) in the single component, the energy migration from Dy(3+) to Eu(3+) has been demonstrated to be a resonant type via a dipole-quadrupole mechanism as well as that from Tm(3+) to Dy(3+) ions, of which the critical distance (R(Dy-Eu)) is calculated to be 11.08 Å. More significantly, in the Tm(3+), Dy(3+), and Eu(3+) tridoped NaGd(WO4)2 phosphors, the energy migration of Tm(3+)-Dy(3+)-Eu(3+), utilized for sensitizing Eu(3+) ions besides compensating the red component at low Eu(3+) doping concentration, has been discussed first. In addition, under 365 nm near-ultraviolet radiation (nUV), the color-tunable emissions in octahedral NaGd(WO4)2 microcrystals are realized by giving abundant blue, green, white, yellow, and red emissions, especially warm white emission, and could be favorable candidates in full-color phosphors for nUV-LEDs.

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Novel type III anisotropic conductive films (ACFs), namely flexible Janus-typed membranes, were proposed, designed and fabricated for the first time. Flexible Janus-typed membranes composed of ordered Janus nanobelts were constructed by electrospinning, which simultaneously possess fluorescence and double electrically conductive anisotropy. For the fabrication of the Janus-typed membrane, Janus nanobelts comprising a conductive side and an insulative-fluorescent side were primarily fabricated, and then the Janus nanobelts are arranged into parallel arrays using an aluminum rotary drum as the collector to obtain a single anisotropically conductive film. Subsequently, a secondary electrospinning process was applied to the as-prepared single anisotropically conductive films to acquire the final Janus-typed membrane. For this Janus-typed membrane, namely its left-to-right structure, anisotropic electrical conduction synchronously exists on both sides, and furthermore, the two electrically conductive directions are perpendicular. By modulating the amount of Eu(BA)phen complex and conducting polyaniline (PANI), the characteristics and intensity of the fluorescence-electricity dual-function in the membrane can be tuned. The high integration of this peculiar Janus-typed membrane with simultaneous double electrically conductive anisotropy-fluorescent dual-functionality is successfully realized in this study. This design philosophy and preparative technique will provide support for the design and construction of new types of special nanostructures with multi-functionality.

A series of Dy(3+) or/and Eu(3+) doped GdVO4 phosphors were successfully prepared by a simple hydrothermal method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectrometry (EDS), photoluminescence (PL) spectroscopy and vibrating sample magnetometry (VSM). The results indicate that the as-prepared samples are pure tetragonal phase GdVO4, taking on nanoparticles with an average size of 45 nm. Under ultraviolet (UV) light excitation, the individual Dy(3+) or Eu(3+) ion activated GdVO4 phosphors exhibit excellent emission properties in their respective regions. The mechanism of energy transfer from the VO4(3-) group and the charge transfer band (CTB) to Dy(3+) and Eu(3+) ions is proposed. Color-tunable emissions in GdVO4:Dy(3+),Eu(3+) phosphors are realized through adopting different excitation wavelengths or adjusting the appropriate concentration of Dy(3+) and Eu(3+) when excited by a single excitation wavelength. In addition, the as-prepared samples show paramagnetic properties at room temperature. This kind of multifunctional color-tunable phosphor has great potential applications in the fields of photoelectronic devices and biomedical sciences.

Multifunctional nanomaterials possessing upconversion luminescence, magnetic, and photothermal properties show promising applications in biology and medicine. In this study, a new kind of luminescent-magnetic-thermal core–shell hybrid nanocomposite was fabricated combining rare earth Yb3+ and Er3+ ions doped NaGdF4 nanocrystals as shell layer materials and gold nanorods (AuNRs) as cores. The structure, morphology, composition, and properties of the multifunctional hybrid nanocomposites were characterized by X-ray powder diffraction, transmission electron microscopy, energy dispersive spectroscopy, upconversion photoluminescence spectra, vibrating sample magnetometer, sensitive thermometer, and cytotoxicity assessment, respectively. The multifunctional hybrid nanocomposites have rodlike morphology and core–shell structure. The uniform NaGdF4/Yb3+,Er3+ shell with a thickness of around 4.5 nm was coated on the surface of AuNRs with a length of 40 nm and a diameter of 12 nm. The AuNRs@NaGdF4/Yb3+,Er3+ multifunctional nanocomposites provide an excellent upconversion emission under excitation at 980 nm and a superparamagnetic behavior with magnetic susceptibility of 8.0 × 10–5 emu·g–1·Oe–1 at 300 K and saturation magnetization value of 102 emu·g–1 at 2 K. More significantly, when AuNRs@NaGdF4/Yb3+,Er3+ aqueous suspensions of 100 μg·mL–1 were irradiated by a 980 nm NIR laser for 10 min, the temperature was significantly elevated to 48 °C. At the same time, the temperature of photothermal transduction can be easily controlled by adjusting the concentration of nanocomposites. Preliminary investigation of incubating with HeLa cells displays that the multifunctional nanocomposites exhibit a good biocompatibility. Moreover, the nanocomposites may be effectively utilized for bioimaging and photothermal therapy in living cells.

Tb(3+) and/or Sm(3+) doped NaGdF4 luminescent nanomaterials have been successfully synthesized by an SDS-assisted one-step hydrothermal method. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), X-ray energy dispersive spectrometer (EDS), photoluminescence (PL) spectra and a vibrating sample magnetometer (VSM). The results show that the synthesized samples are all pure β-NaGdF4. The as-prepared Tb(3+) or Sm(3+) doped samples show strong green and yellow emission, originating from the allowed (5)D3→(7)F(J) (J = 5, 4, 3, 2) and (5)D4→(7)F(J) (J = 6, 5, 4, 3) transitions of the Tb(3+) ions and the (4)G(5/2)→(6)H(5/2), (6)H(7/2), (6)H(9/2) transition of the Sm(3+) ions. Based on the excitation wavelengths, multiple (yellowish green, yellow, white) emissions are obtained by Sm(3+) ion co-activated NaGdF4:Tb(3+) phosphors. Moreover, an energy transfer from Tb(3+) to Sm(3+) is observed, which is justified through the luminescence spectra and the fluorescence decay curves. Furthermore, the resonance-type energy transfer from Tb(3+) to Sm(3+) is demonstrated to occur via the dipole-dipole mechanism. In addition, the obtained samples also exhibit paramagnetic properties at room temperature. It is obvious that these multifunctional Tb(3+), Sm(3+) co-doped β-NaGdF4 nanomaterials, with tunable multicolors and intrinsic paramagnetic properties, may have potential application in the fields of full-color displays, biological labels, bioseparation and magnetic resonance imaging.