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.
Novel Janus nanoribbons arrays with excellent electrically conductive anisotropy, magnetism, and photoluminescence are prepared via electrospinning technology. Based on the unique nanostructure, conductance in the direction parallel to the Janus nanoribbons is almost eight orders of magnitude higher than that in the perpendicular direction, which is by far the most excellent conductive anisotropy for anisotropic conductive materials.
Transition-metal tetravalent manganese ions (Mn4+) as luminescence center of red phosphors have drawn much attention owing to their broad-band absorption extended from UV to blue regions and narrow ...red-emissive band. In the present work, a series of Mn4+-doped BaGeF6 red phosphors were obtained via hydrothermal method. X-ray powder diffraction, energy-dispersive X-ray spectrometer, scanning electron microscope, and photoluminescence spectra were employed to determine the crystal structure, composition, morphology, and photoluminescence properties of all samples. The prepared BaGeF6:Mn4+ samples demonstrate two dominant broadband absorption at near-UV (∼366 nm) and blue regions (∼470 nm) and intense red emissions (∼635 nm) under 470 nm excitation. In addition, the morphology and the emission intensities were successfully controlled by adjusting doping concentrations, reaction times, reaction temperatures, barium sources, and surfactants. Concentration quenching and thermal quenching mechanisms were studied in detail. When the BaGeF6:Mn4+ red phosphor was introduced into the light-emitting diode, warm white light-emitting diodes (w-LEDs) were successfully fabricated, which have high color rendering index (Ra = 86.3) and low correlated color temperature (4766 K), indicating that the BaGeF6:Mn4+ red phosphor provides a good opportunity for application in w-LEDs.
Coupling effect of chemical composition and physical structure is a key factor to construct superaerophobic electrodes. Almost all reports about superaerophobic electrodes were aimed at precisely ...controlling morphology of loaded materials (constructing specific structure) and ignored the due role of substrate. Nevertheless, in this work, by using high precision and controllable femtosecond laser, hierarchical micro-nano structures with superaerophobic properties were constructed on the surface of silicon substrate (fs-Si), and such special super-wettability could be successfully inherited to subsequent self-supporting electrodes through chemical synthesis. Femtosecond laser processing endowed electrodes with high electrochemical surface area, strong physical structure, and remarkable superaerophobic efficacy. As an unconventional processing method, the reconstructed morphology of substrate surface bears the responsibility of superaerophobicity, thus liberating the structural constraints on loaded materials. Since this key of coupling effect is transferred from the loaded materials to substrate, we provided a new general scheme for synthesizing superaerophobic electrodes. The successful introduction of femtosecond laser will open a new idea to synthesize self-supporting electrodes for gas-involving reactions.
In order to achieve high-yielding rate of Janus microfibers in electrospun product, conjugate electrospinning is employed via optimization of electrospinning conditions. Further, Janus microfibers ...array affording dual-functional performance of magnetism and fluorescence is fabricated by above technique. The unique structure has the advantage of realizing complete separation of fluorescent materials from magnetic nanoparticles, which can ensure high fluorescent intensity without remarkably adverse effect of magnetic substance. The diameter of the fibers in the array is 11.72 ± 0.09 μm. The emission peaks of Tb3+ are found and assigned to the transitions of 5D4 → 7F6 (490 nm), 5D4 → 7F5 (545 nm), 5D4 → 7F4 (581 nm) and 5D4 → 7F3 (620 nm). Compared with the counterpart contrastive samples, Janus microfibers array present higher comprehensive performance owing to the exceptional structure and directionally ordered arrangement. Moreover, the saturation magnetization can be tailored from 3.6 emu·g−1 to 24.0 emu·g−1via adding various amounts of Fe3O4 NPs. This work provides an effective method to fabricate other advanced multifunctional materials.
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•High-yielding rate of Janus microfibers in the product is designed and actualized via conjugate electrospinning.•Magnetism and fluorescence are highly integrated into a single Janus microfiber.•Adverse influence of magnetic material on fluorescent material is greatly reduced.•Fabrication technique can be popularized to obtain other Janus multifunctional materials.
Y
2
O
2
S:Eu
3+
nanobelts were successfully prepared via electrospinning method and sulfurization process using the as-prepared Y
2
O
3
:Eu
3+
nanobelts and sulfur powders as sulfur source by a ...double-crucible method for the first time. X-ray diffraction analysis indicated that the Y
2
O
2
S:Eu
3+
nanobelts were pure hexagonal in structure with space group
P
m
1. Scanning electron microscope images showed that the width and thickness of the Y
2
O
2
S:Eu
3+
nanobelts were ca. 6.7 μm and 125 nm, respectively. Under the excitation of 325-nm ultraviolet light, Y
2
O
2
S:Eu
3+
nanobelts exhibited red emissions of predominant peaks at 628 and 618 nm, which are attributed to the
5
D
0
→
7
F
2
transition of the Eu
3+
ions. It was found that the optimum doping concentration of Eu
3+
ions in the Y
2
O
2
S: Eu
3+
nanobelts was 3 %. Compared with bulk particle, Eu
3+
–O
2−
/S
2−
charge transfer bands (260 and 325 nm) of the Y
2
O
2
S:Eu
3+
nanobelts showed a blue-shift significantly. The formation mechanism of the Y
2
O
2
S: Eu
3+
nanobelts was also proposed. This new sulfurization technique is of great importance, not only to inherit the morphology of rare earth oxides but also to fabricate pure-phase rare earth oxysulfides at low temperature compared with conventional sulfurization method.
A simple sol–gel method combined with hydrothermal synthesis technique were used to synthesize the rutile TiO
2
nanoparticles without any other impurities and TiO
2
/carbon quantum dots (CQDS) ...composite photocatalysts with a special defective structure. The particles of TiO
2
nanoparticles and TiO
2
/CQDS composite photocatalysts are approximately spherical. The average particle size of TiO
2
nanoparticles and TiO
2
/CQDS composite photocatalysts are 45 and 25 nm, respectively. The TiO
2
/CQDS composite photocatalysts exhibits high optical absorption coefficient in the UV–Vis region, high oxygen defect concentration, lower optical bandgap value and high photocatalytic activity for the degradation of dimethyl sulfoxide (DMSO). Based on the energy band theory, a corresponding photocatalytic mechanism of TiO
2
/CQDS composite photocatalysts was proposed. This strategy provides a new idea for the synthesis of CQDS decorated other metal oxide photocatalysts.
In this work, a 3D Z-scheme photocatalyst Ag/AgBr/Zn
3
V
2
O
7
(OH)
2
·2H
2
O (Ag/AgBr/ZVO) was synthesized by a hydrothermal method, and a subsequent surface deposition-optical reduction technique. ...The prepared flower-like Ag/AgBr/ZVO was characterized by scanning election microscopy (SEM), x-ray powder diffraction (XRD), x-ray photoelectron spectroscopy (XPS), UV-vis spectrophotometry, N
2
adsorption-desorption isotherm based on Brunauer-Emmett-Teller (BET) theory, and electrochemical tests. The photocatalytic degradation performance of the catalyst was investigated by the degradation of methylene blue (MB) dye by visible light irradiation. Compared with bare Zn
3
V
2
O
7
(OH)
2
·2H
2
O (ZVO) nanoflowers, the photocatalytic effect of the 3D Z-scheme heterojunction Ag/AgBr/ZVO was significantly enhanced. The catalyst of 2h-Ag/AgBr/ZVO exhibited the strongest photocatalytic activity, of which the MB degradation rate is about 98.8% in 100 min, which was about five times that of pure ZVO. The increase in the photodegradation rate is ascribed to the accelerated interface charge-transfer process, the faster photogenerated carrier separation rate and the enhancement of visible light absorption. In view of the trapping of the reaction intermediate and the electron spin resonance (ESR) measurement, we propose a possible Z-scheme photocatalytic mechanism. This improved visible-light response likely originates from a synergistic effect of the different components. This work offered an ideal method for producing stable, efficient, and recyclable photocatalysts suitable for use in the visible light range.
Water splitting was considered to be a sustainable and promising strategy for production of clean hydrogen energy to address environmental crisis and potential energy. In this work, we present the ...cost-effective, convenient, and efficient method for in situ growth of peculiar MoS
2
–Ni
3
S
2
nanoflake heterostructures on three-dimensional (3D) Ni foam. The synthesized electrocatalyst was used as a self-supported bifunctional electrode to catalyze oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), and it exhibits an overpotential of 125 mV to achieve 10 mA cm
−2
for HER and an overpotential of 280 mV to achieve 40 mA cm
−2
for OER. In addition, the material presents a cell voltage of only 1.556 V (10 mA cm
−2
) for overall water splitting in 1 M KOH solution and a robust durability and long-term stability (over 50 h at 10 mA cm
−2
). The excellent electrocatalytic performance with superior stability is mainly due to the 3D porous conductive substrates, peculiar layered heterostructures, superhydrophilic surfaces, and synergistic advantages of bimetallic sulfides. The material has a great application prospect as an earth-abundant electrocatalyst in water splitting for large-scale hydrogen or oxygen production.
The MWCNTs-NaGdF4:Yb3+, Er3+, Eu3+ multifunctional nanocomposites with magnetic, luminescent and thermal conversion properties were fabricated by a facile hydrothermal method, the up-conversion ...luminescence imaging, X-ray computed tomography imaging and photothermal therapy of nanocomposites were investigated. The obtained nanocomposites would have promising applications in diagnosis and therapy of tumors.
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Multifunctional nanocomposites (NCs) incorporating magnetic, luminescent and photothermal conversion properties are endowed with potential application in many fields such as imaging, tumor detection, drug delivery and therapy. Here, multifunctional MWCNTs-NaGdF4:Yb3+, Er3+, Eu3+ NCs, which offer the potential for integrated bioimaging and photothermal therapy (PTT) were fabricated by a facile hydrothermal method. The resulting sample exhibits uniform morphology, bright dual-modal luminescence and intrinsic paramagnetic properties. Under near-infrared laser excitation, NCs have excellent photothermal conversion properties. In addition, the MTT assay in HeLa cells shows that the NCs have good biocompatibility. Moreover, the up-conversion luminescence (UCL) imaging, X-ray computed tomography (CT) imaging and PTT in vitro of NCs were investigated. The results indicate that NCs can be used for dual-modal imaging-guided diagnose and PTT of cancer cells.
A Eu(BA)
3
phen/polyvinyl pyrrolidone (PVP)//Fe
3
O
4
/PVP Janus-type nanofibers array membrane (JNAM) concurrently displaying dual-functionality of improved red luminescence and tuneable ...superparamagnetism is successfully built by conjugative electrospinning. Conjugative electrospinning has lower claims on the similarity of the viscosity of two types of spinning dope than parallel electrospinning, so there’s no need to keep identical viscosity between two spinning dopes. This technique solves the dilemma of diffusion between two spinning dopes in parallel electrospinning process using two ordinary spinnerets for electrospinning, and entirely separates superparamagnetic nanoparticles from luminescent molecules. It is found that luminescent performance of JNAM is stronger than that of counterpart Janus-type nanofibers non-array membrane. The superparamagnetism of JNAM can be regulated by varying internal Fe
3
O
4
NPs amount. The JNAM possesses latent application value in display devices, nanotechnology, etc. due to the improved red luminescence and tuneable superparamagnetism. Furthermore, this design notion and manufacturing approach furnish a route for constructing other unidimensional multifunctional Janus-type nanomaterials.
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