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Limited light harvesting and charge collection are recognized as grand challenges for the exploration of highly efficient TiO2 photoanodes. To overcome these intrinsic shortcomings, we reported the...

Currently, all-inorganic CsPbX3 (X = Br, I, Cl) perovskite nanocrystals (NCs) are shining stars with exciting potential applications in optoelectronic devices such as solar cells, light-emitting diodes, lasers, and photodetectors, due to their superior performance in comparison to their organic–inorganic hybrid counterparts. In the present work, we report a general strategy based on a microwave technique for the rapid production of low-dimensional all-inorganic CsPbBr3 perovskite NCs with tunable morphologies within minutes. The effect of the key parameters such as the introduced ligands, solvents, and PbBr2 precursors and microwave powers as well as the irradiation times on the production of perovskite NCs was systematically investigated, which allowed their growth with tunable dimensionalities and sizes. As a proof of concept, the ratio of OA to OAm as well as the concentration of PbBr2 precursor played important roles in triggering the anisotropic growth of the perovskite NCs, favoring their growth int...

In the present work, we reported the exploration of photoanodes based on mesoporous WO3 nanobelts through a foaming-assisted electrospinning strategy. The introduced polyvinylpyrrolidone in the raw solutions played a determining role on the formation of the nanobelts, enabling their fabrication in a controlled manner. The as-fabricated mesoporous WO3 nanobelts exhibited a photocurrent density of 311 μA cm−2 and incident photon-to-current efficiency of 6.5 % at 350 nm and 1.2 V vs. Ag/AgCl under simulated sunlight illumination, which are 2.3 times to that of cylindrical nanofibers. Furthermore, our discovery confirmed that, in comparison to the conventionally cylindrical nanofibers, the nanobelts with a rectangular cross section could be a better candidate for constructing photoanodes with enhanced photoelectrochemical efficiency and stability.

Low turn-on fields together with boosted stabilities are recognized as two key factors for pushing forward the implementations of the field emitters in electronic units. In current work, we explored superior flexible field emitters based on single-crystalline 3C-SiC nanowires, which had numbers of sharp edges, as well as corners surrounding the wire body and B dopants. The as-constructed field emitters behaved exceptional field emission (FE) behaviors with ultralow turn-on fields (Eto) of 0.94–0.68 V/μm and current emission fluctuations of ±1.0–3.4%, when subjected to harsh working conditions under different bending cycles, various bending configurations, as well as elevated temperature environments. The sharp edges together with the edges were able to significantly increase the electron emission sites, and the incorporated B dopants could bring a more localized state close to the Fermi level, which rendered the SiC nanowire emitters with low Eto, large field enhancement factor as well as robust current e...

In this work, we report the fabrication of BiVO4 nanobelts with tailored structures by an electrospinning technique. The as-fabricated BiVO4 nanobelts exhibited enhanced photodegradation of Rhodamine B as well as photoelectrocatalytic water splitting performance in comparison to the conventional nanofibers, suggesting their promising applications in environmental treatment and energy conversion.

Photocatalytic hydrogen evolution is a promising solution to energy and environmental problems. The grand challenge for its application is how to make photocatalysts with satisfactory efficiency. In the present work, exploration of Ag@TiO2 mesoporous nanofibers via two strategies is reported, namely in situ electrospinning preparation (strategy I) and electrospinning combined with subsequent photodeposition (strategy II). The photocatalytic behavior of the as-synthesized Ag@TiO2 hybrid nanofibers was evaluated in terms of hydrogen evolution efficiency for the photodecomposition of water under Xe lamp irradiation. It was found that incorporation of Ag nanoparticles into the TiO2 mesoporous nanofibers could enhance remarkably their photocatalytic efficiency. The products prepared through strategy I exhibited the highest photocatalytic performance as compared with those prepared by strategy II. Current work might give some insight into exploration of stable binary photocatalysts, which have potential applications for efficient hydrogen evolution.

Improving the photocatalytic efficiency of TiO2 semiconductor is crucially important and highly desired for its practical applications. In the present work, aiming to broaden the photoresponse window and limit the photocatalyst aggregation, we reported the exploration of N-doped TiO2 thoroughly mesoporous nanofibers with high purity in morphology via a foaming-assisted electrospinning strategy. The foaming agents and urea were introduced in the raw materials to create the mesopores and incorporate the N dopants into the conventional solid TiO2 nanofibers, respectively, which could be accomplished simultaneously over one-step calcination process. The synergetic combination of N dopants and one-dimensional mesoporous nanostructure allow the TiO2 fibers to exhibit significantly enhanced visible-light photocatalytic activity toward the Rhodamine B and hydrogen evolution, as compared to those of N-doped solid and intrinsic thoroughly mesoporous counterparts, suggesting their promising applications in water purification and energy supply.

In the present work, we reported the current emission from P-doped SiC nanowire field emitters, which were synthesized via catalyst-assisted pyrolysis of polysilazane precursors. Directed by F–N theory for enhanced field emission (FE) behaviors, the emitters were grown into nanostructures with two desired characteristics, namely with an ultrahigh aspect ratio as well as incorporated P dopants, which brought profound enhancements to the field enhancement factor (β) and turn-on field (Eto). The as-grown SiC nanowires (SiCNWs) exhibit an aspect ratio over 1500 with a uniform spatial distribution of P dopants. The FE measurements exhibit that the SiCNWs possessed a field enhancement factor up to 11657 and an ultralow Eto of 0.47 V μm−1, which was little achieved among the reported studies. The current emission fluctuations are ∼±4.0% over 5 h, suggesting their good electron emission stability. We mainly attributed the totally excellent FE performances to the ultra-high aspect ratio and the incorporated P dopants of the obtained SiCNWs, which could synergistically cause a significant increase of the field enhancement factor and a decrease of the work function.

A novel and highly efficient visible-light-driven photocatalyst with robust stability, made up of thoroughly mesoporous TiO2/WO3/g-C3N4 ternary hybrid nanofibers, has been fabricated through a foaming-assisted electrospinning process followed by a solution dipping process. These fibers, without the assistance of a noble metal, yielded a high visible-light-driven photocatalytic H2 release rate of ∼286.6 μmol h−1, which was 65 times greater than that displayed by the pure TiO2 counterparts.

Silicon carbide (SiC) is recognized as a promising substitute for the currently used Si for exploring robust pressure sensors with desired high sensitivities and excellent abilities to serve under harsh work conditions. In the present work, we reported the giant piezoresistance effect of p-type 3C-SiC nanowires with B dopants, which were synthesized by catalyst-assisted pyrolysis of polysilazane. The transverse electromechanical properties of SiC nanowires were investigated at loading forces applied using a conductive atomic force microscopy (C-AFM) tip. The resistances of the as-synthesized SiC nanowires exhibit an increase with the increase of compressed stresses at the same bias voltages, representing their negative piezoresistance behaviors. The measured negative piezoresistance coefficient π[10] of the nanowire fell in the range of −8.83 to −103.42 × 10−11 Pa−1 as the applied loading forces ranged from 51.7 to 181.0 nN. The giant gauge factor (GF) could be up to −620.5, which was enhanced by more than 10 times compared to the highest ever reported for SiC nanostructures.

Silicon carbide (SiC) nanostructures are considered as an excellent candidate for field emitters, owning to their versatile superior properties. The field emission with a low turn-on field (Eto) is crucial and highly desired for their practical application. In the present study, SiC nanowires (SiCNWs) were grown on carbon fabrics via the pyrolysis of a polymeric precursor, followed by surface decoration with Au nanoparticles by a sputtering process. The characterizations of their field emission (FE) properties revealed that the Au nanoparticle-decorated SiC nanowires exhibit remarkably enhanced FE performances. Compared to those of the bare counterparts (i.e., without the Au nanoparticle decoration), the Eto of Au decorated SiCNWs was decreased drastically from 2.10 to 1.14 V μm−1. The field enhancement factor (β) of the Au decorated SiCNWs was ca. 6244 ± 50, which is nearly 6 times that of the bare counterparts. The enhanced FE behaviors were mainly attributed to the synergistically increased β and decreased Φ of the SiCNWs induced by Au decoration.

In this work, polycrystalline WO3 nanobelts were fabricated via an electrospinning process combined with subsequent air calcination. The resultant products were characterized by X-ray diffraction, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy in regard to the structures. It has been found that the applied voltage during the electrospinning process played the determined role in the formation of the WO3 nanobelts, allowing the controlled growth of the nanobelts. The ultraviolet (UV) photodetector assembled by an individual WO3 nanobelt exhibits a high sensitivity and a precise selectivity to the different wavelength lights, with a very low dark current and typical photo-dark current ratio up to 1000, which was the highest for any WO3 photodectectors ever reported. This work could not only push forward the facile preparation of WO3 nanobelts but also represent, for the first time, the possibility that the polycrystalline WO3 nanobelts could be a promising building block for the highly efficient UV photodetectors.

Current emission stability is one of the key issues for field emitters for them to be practically applied as electron sources. In the present work, large-scale and well-aligned B-doped SiC nanoneedle arrays have been grown on 6H-SiC wafer substrates via pyrolysis of polymeric precursors. The measured field emission (FE) characteristics suggest that the turn-on fields of the as-synthesized SiC nanoneedle arrays are reduced from 1.92 to 0.98 V μm(-1) with temperature increasing from room temperature (RT) to 500 °C, suggesting their excellent FE performances. The slightly changed current fluctuations (only ∼1.3%) between RT and 200 °C confirm that the present SiC nanoarrays with B dopants could be highly stable field emitters to be used in service under harsh conditions of high temperatures.

1D large-pore mesoporous ZnO materials have attracted tremendous attention because of their outstanding properties and promising applications in a wide range of fields. In the present work, we report the fabrication of large-pore mesoporous ZnO nanofibers via an improved electrospinning strategy, namely, the foaming-assisted electrospinning technique, combined with subsequent calcination treatment. The as-fabricated large-pore mesoporous nanofibers were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) specific surface area (SBET). The obtained products possess well-designed 1D mesoporous nanostructure with high purity and homogeneous large pore sizes. It is found that the content of the foaming agent within the solutions plays a crucial role in the formation of large-pore mesoporous ZnO nanofibers, enabling the growth of the fibers in a controlled manner. The resultant large-pore mesoporous nanofibers exhibit excellent photocatalytic activity and significant stability for hydrogen production compared to conventional solid nanofibers. The present work suggests a facile preparation of the large-pore mesoporous ZnO nanofibers, which may open new doors for their potential applications in photocatalysts.

Fabrication of well-aligned one-dimensional (1D) nanostrucutres is critically important and highly desired since it is the key step to realize the patterned arrays to be used as the display units. In the present work, we report the large-scale and well-aligned growth of n-type SiC nanowire arrays on the 6H-SiC wafer substrates via pyrolysis of polymeric precursors assisted by Au catalysts. The obtained n-type SiC nanowires are highly qualified with sharp tips and numerous sharp corners around the wire bodies, which bring the emitters excellent field emission (FE) performance with low turn-on fields (1.50 V/μm), low threshold fields (2.65 V/μm), and good current emission stabilities (fluctuation3.8%). The work abilities of the n-type SiC tower-like nanowire arrays under high-temperature harsh environments have been investigated, suggesting that the resultant field emitters could be well serviced up to 500 °C. The temperature-enhanced FE behaviors could be attributed to the reduction of the work function induced by the rise of temperatures and the incorporated N dopants. It is believed that the present well-aligned n-type SiC tower-like nanowire arrays could meet nearly all stringent requirements for an ideal FE emitter with excellent FE properties, making their applications very promising in displays and other electronic nanodevices.

TiO 2 nanoparticles are easily aggregated, which greatly hinders their application to be utilized as photocatalysts. One of the effective routes is to make the TiO 2 nanoparticles assembled on/in a solid carrier. In current work we report the fabrication of hybrid TiO 2 /SiO 2 fibers with tunable internal porous structures via a capillary electrospinning technique combined with subsequent high-temperature pyrolysis treatment, in which the porous SiO 2 fiber frameworks could offer a platform to assemble the TiO 2 nanoparticles with a uniform spatial distribution. The resultant fibers were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). It is found that the introduced concentration of tetrabutyl titanate (TBOT) plays a profound effect on the formation of the hybrid TiO 2 /SiO 2 fibers. The experimental results suggest that tailoring the concentrations of raw material in the precursor solutions could permit the formation of internal structures with solid, hollow and hierarchically porous shapes, enabling the fabrication of hybrid TiO 2 /SiO 2 fibers with tunable structures. Present work could provide a facile strategy for limiting the aggregation of TiO 2 nanoparticles, which could give them a promising high photocatalysis performance.

Recently, preparation of mesoporous fibers has attracted extensive attentions because of their unique and broad applications in photocatalysis, optoelectronics, and biomaterials. However, it remains a great challenge to fabricate thoroughly mesoporous nanofibers with high purity and uniformity. Here, we report a general, simple and cost-effective strategy, namely, foaming-assisted electrospinning, for producing mesoporous nanofibers with high purity and enhanced specific surface areas. As a proof of concept, the as-fabricated mesoporous TiO2 fibers exhibit much higher photocatalytic activity and stability than both the conventional solid counterparts and the commercially available P25. The abundant vapors released from the introduced foaming agents are responsible for the creation of pores with uniform spatial distribution in the spun precursor fibers. The present work represents a critically important step in advancing the electrospinning technique for generating mesoporous fibers in a facile and universal manner.

TiO2 semiconductor is one of the important photocatalysts for solar light conversion. The challenge is how to improve their efficiency. Creation of porous structures on/in the fibers could favor them a higher surface area as compared to the conventional solid counterparts, which thus could make the achievement for the desired high efficiency. In present work, we report the fabrication of porous TiO2 fibers with high purity via electrospinning of butyl titanate (TBOT) and polyvinylpyrrolidone (PVP) combined with the subsequent calcination in air. It is found that the TBOT content in the spinning solution plays a profound effect on the growth of the fibers, enabling the synthesis of porous TiO2 fibers with tunable structures and high purity. The photocatalytic activity for hydrogen evolution of the as-fabricated TiO2 nanostrcutres has been investigated, suggesting that porous TiO2 nanomaterials with a high purity and well-defined one-dimensional fiber shape could be an excellent candidate to be utilized as the photocatalyst for hydrogen evolution.

With respect to the effect of local field enhancement, fabrication of nanostructures with clear and sharp tips is critically important for the exploration of field emitters with high performances. In the present work, aimed at the exploration of the flexible SiC field emitters with excellent properties, we report the controlled growth of quasialigned SiC nanoarrays with sharp tips via catalyst assisted pyrolysis of polymeric precursors on the carbon fabric substrates by tailoring the cooling rates. The resultant products are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). It is found that the growth of SiC quasialigned nanoneedle arrays with unique sharp tips could be achieved by reducing the cooling rates over the high-temperature pyrolysis process, enabling the capability for the controlled growth of SiC flexible field emitters on carbon fabric. The cooling rates are optimized, which suggests that 17.5 °C min−1 is low enough to favor the growth of SiC nanowires with clear and sharp tips. The growth of the quasialigned SiC nanoarrays with sharp tips based on the typical VLS mechanism has been proposed. The FE property measurements suggest that the electron emission could be remarkably enhanced by tailoring the growth of SiC nanowires with clear and sharp tips.

In this study, beard-like and sea cucumber-like silica structures have been successfully synthesized on the Si substrate by a novel and simple water assisted method. The investigation of SEM and TEM reveals that the as-grown products possess many similar features like that they all have a very big, nearly spherical microsized body and uncountable, high density and highly oriented silica nanowire antennas. It is proved that ultrafine nanosized metal catalysts could be generated on the surface of one microsized catalyst during their growth process due to the indications of surface local softening and different elastic deformation along different crystal plane taking place on the catalyst surface during growth process. Our results could introduce a new way to control the growth of high-density and well-oriented functional nanowire arrays with desired morphologies.

In this study, the dielectrophoretic processes of SiC nanowires suspended in three typical solvents, (highly purified water, ethanol and isopropanol) were systematically investigated. Optical microscope and SEM characterizations were used to observe the order of SiC nanowires on the surface of gold microchannels. The gold microchannels were induced by Ac dielectrophoresis of the corresponding dispersion solutions of SiC nanowires, with a concentration of 0.1 mg/mL. The study shows that the dielectrophoresis process is an effective way of synthesizing highly oriented SiC nanoarrays using isopropanol solution. The results also show that the arrangement of SiC nanowires on the interdigital electrode configuration not only depend on the kind of solvent used, but also on the applied frequency (1000 Hz∼1 MHz) and voltage (1 V∼20 V).

Development of novel hybrid photocatalysts with high efficiency and durability for photocatalytic hydrogen generation is highly desired but still remains a grand challenge currently. In the present work, we reported the exploration of ternary hybrid TiO2/CuO/Cu thoroughly mesoporous nanofibers via a foaming-assisted electrospinning technique. It is found that by adjusting the Cu contents in the solutions, the unitary (TiO2), binary (TiO2/CuO, TiO2/Cu), and ternary (TiO2/CuO/Cu) mesoporous products can be obtained, enabling the growth of TiO2/CuO/Cu ternary hybrids in a tailored manner. The photocatalytic behavior of the as-synthesized products as well as P25 was evaluated in terms of their hydrogen evolution efficiency for the photodecomposition water under Xe lamp irradiation. The results showed that the ternary TiO2/CuO/Cu thoroughly mesoporous nanofibers exhibit a robust stability and the most efficient photocatalytic H2 evolution with the highest release rate of ∼851.3 μmol g(-1) h(-1), which was profoundly enhanced for more than 3.5 times with respect to those of the pristine TiO2 counterparts and commercial P25, suggesting their promising applications in clean energy production.

1D mesoporous materials have attracted extensive interest recently, owning to their fascinating properties and versatile applications. However, it remains as a grand challenge to develop a simple and efficient technique to produce oxide nanofibers with mesoporous architectures, controlled morphologies, large surface areas, and optimal performances. In this work, a facile foaming-assisted electrospinning strategy with foaming agent of tea saponin is used to produce thoroughly mesoporous ZnO nanofibers with high purity and controlled morphology. Interestingly, mesoporous fibers with elliptical cross-section exhibit the significantly enhanced photocatalytic activity for hydrogen production, as compared to the counterparts with circular and rectangular cross-sections, and they also perform better than the commercial ZnO nanopowders. The unexpected shape dependence of photocatalytic activities is attributed to the different stacking modes of the mesoporous fibers, and a geometrical model is developed to account for the shape dependence. This work represents an important step toward producing thoroughly mesoporous ZnO nanofibers with tailored morphologies, and the discovery that fibers with elliptical cross-section render the best performance provides a valuable guideline for improving the photocatalytic performance of such mesoporous nanomaterials.

We report, for the first time, the growth of p-type 6H-SiC nanowires with a unique triangular prism shape via the pyrolysis of polymeric precursors. The resultant wires were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The triangular prism-shaped SiC nanowires are averagely sized at ∼700 nm in edge widths with lengths of up to tens of microns. The wires are single-crystalline with 1 at% Al dopants and grown along the direction of [102]. A mechanism based on a typical vapor–liquid–solid (VLS) process was discussed for the growth of the 6H-SiC wires. Intense visible photoluminescence was observed with two respective strong emission peaks centered at 2.4 and 3.1 eV, suggesting that the p-type 6H-SiC wires could be useful in the fabrication of optoelectronic nanodevices.

The purity and uniformity issues with tunable structures are significant challenges for the fabrication of porous fibers. In the present work, we reported the fabrication of mesoporous SiC fibers via electrospinning of polyureasilazane and polyvinylpyrrolidone combined with subsequent high-temperature pyrolysis treatment. The resultant mesoporous fibers were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). The contents of polyureasilazane within the solutions played a critically important role in the formation of mesoporous SiC fibers, enabling the well-controlled growth of the mesoporous SiC fibers. As compared to the reported works, the as-fabricated mesoporous fibers exhibit very uniform microstructures, very high purities, and highly defined fiber shapes with well-controlled structures, which could inspire and activate their potential applications in photocatalysts and catalyst supports.

In this work, we report the temperature-dependent field emission properties of 3C-SiC nanoneedles (SiCNNs) in the range of room temperature (RT) to 500 °C. SiCNNs are synthesized via catalyst-assisted pyrolysis of a polyaluminasilazane precursor. The obtained SiC nanostructures are needlelike shaped with numerous sharp comers around the tiny tips. Field emission characteristics show that turn-on field (E to ) of as-synthesized SiCNNs are ranged in 1.30 to 0.66 V/μm with the temperature raised from RT to 500 °C. At a fixed electric field of 1.37 V/μm, about a three-order-of-magnitude increase of the emission current level has been observed. We attribute the significant reduction of E to and the remarkable increase of emission current to the decrease of work function induced by the raise of temperatures.

We report the fabrication of Si3N4/SiC nano/nano-composite reinforced by single-crystal low-dimensional nanostructures via spark plasma sintering of nanocomposite powders containing in-situ formed Si3N4 nanowires/nanobelts. The fabricated nanocomposite is analyzed by scanning electron microscopy, X-ray diffraction, transmission electron microscopy and selective area electron diffraction. The results show that the in-situ formed Si3N4 nanowires/nanobelts are uniformly distributed within the matrix. Such a nanocomposite could exhibit improved mechanical properties, due to the superior mechanical properties and uniform distribution of the nano-reinforcements.

Low-dimension semiconductor nanostructures were successfully synthesized by a fast, simple, and low-cost microwave method. By heating raw materials under microwave irradiation and controlled conditions, diverse nanostructures for semiconducting oxides and carbides were synthesized without extra metal catalysts. In this paper, flower-like and net structural oxide and carbide semiconductors in nanoscale have been studied in detail. Structural, morphological, and elemental analysis revealed that the as-synthesized nanostructures were highly pure and structurally uniform. The possible growth mechanisms of these nanostructures were preliminarily discussed. The temperature and the gas-phase supersaturation in their growing processes have important effects on their morphologies. The unique synthesis method may open a new way for the fabrication of self-assembled multidimensional structures, which are expected to find a wide range of important applications in nanodevices and nanocomposites.

We report for the first time the synthesis of Al-doped 6H-SiC nanowires with high yield and high quality. The nanowires were obtained by the catalyst-assisted pyrolysis of polymeric precursors with FeCl2 as the catalyst. The doping concentrations were controlled by tailoring the Al concentrations in the precursors. It was observed that the Al dopants caused red-shifts of the photoluminescence bands. The results suggest a simple technique to synthesize Al-doped SiC nanomaterials in a controlled manner. The obtained nanowires could be useful for making optical and electronic nanodevices.

We report the large-scale synthesis of very thin single-crystalline Si{sub 3}N{sub 4} nanobelts with high yield via catalyst-assisted pyrolysis of polymeric precursors. The obtained nanobelts, which show a perfect crystal structure and smooth surface, are up to several millimeters in length with typical width and thickness of {approx}800 nm and tens of nanometers, respectively. It is believed that the nanobelts were grown via a vapor-solid process, in which Al catalyst played a key role. This result provides a possibility for mass producing high quality, very thin Si{sub 3}N{sub 4} nanobelts. - Graphical abstract: We report the mass production of very thin single-crystalline Si{sub 3}N{sub 4} nanobelts with a high yield via catalyst-assisted pyrolysis of polymeric precursors.

Bismuth vanadate (BiVO4) is considered as a potentially attractive candidate for the O2 evolution and photodegradation of organic pollutants. In an effort to develop visible-light-driven photocatalysts with high activities, the thoroughly mesoporous BiVO4 nanofibers were fabricated via a foaming-assisted electrospinning strategy. It was found that the introduced foaming agent of diisopropyl azodiformate within the solutions plays a crucial role on the formation of thoroughly mesoporous BiVO4 nanofibers, making their growth tunable. The obtained mesoporous BiVO4 nanofibers possess well-defined one-dimensional mesoporous architectures with high purity in their morphology and a surface area of 22.5 m(2)/g, which is ∼4 times that of conventional solid counterparts (5.8 m(2)/g). Accordingly, they exhibit much higher efficient photocatalytic activities toward the degradation of rhodamine B under visible-light irradiation, which is 3 times that of conventional solid counterparts, suggesting their promising application as novel and efficient photocatalysts for water purification.

In this paper, we have demonstrated the Oswald ripening growth of single-crystalline Si3N4 nanoplates. The formation of the plates involves three basic steps: formation and aggregation of the nanoparticles, grain coalescence within selective areas, and growth of one coarsened grain at the expense of the rest of the nanoparticles via an Oswald ripening process assisted by the oriented attachment mechanism. The obtained nanoplates exhibit an extremely high aspect ratio with an ultrathin thickness, flat surface, and perfect crystal structure, and they could be utilized as substrates for constructing nanodevices.

Hollow Al2O3 microsphere chain networks have been synthesized via a simple two-staged pyrolysis of a precursor using active carbon powders as the template. The obtained networks are characterized using scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The chain networks are formed by subsequent aggregation of the prior formed hollow Al2O3 microspheres. The obtained chain networks are promising for the applications in catalyst support, filtration, and other applications due to their lightweight and highly porous nature.

In this work, we reported the energy transfer between Mn doped CdS quantum dots (Mn:CdS QDs) with the core–shell structure of MnS/ZnS/CdS and 1,3,5-tris(N-phenylbenz-imidazol-2,yl) benzene (TPBI) in inorganic/organic blend films by steady-state and time-resolved photoluminescence (PL) spectroscopy. The changes in PL excitation intensity of the Mn:CdS QDs and PL lifetime of the TPBI clearly demonstrate an efficient energy transfer process from TPBI to QDs in the blend films. Further, it is found that the efficiency of Forster resonance energy transfer increases with the increasing of the thicknesses of CdS shell. These results highlight the potential of Mn doped QDs for fabricating high-performance QD lightemitting diodes. © 2014 The Japan Society of Applied Physics

Increasing the electron emission site density of nanostructured emitters with limited field screening effects is one of the key issues for improving the field emission (FE) properties. In this work, we reported the Au-nanoparticles-density-dependent field emission behaviors of surface-decorated SiC nanowires. The Au nanoparticles (AuNPs) decorated around the surface of the SiC nanowires were achieved via an ion sputtering technique, by which the densities of the isolated AuNPs could be adjusted by controlling the fixed sputtering times. The measured FE characteristics demonstrated that the turn-on fields of the SiC nanowires were tuned to be of 2.06, 1.14, and 3.35 V/μm with the increase of the decorated AuNPs densities, suggesting that a suitable decorated AuNPs density could render the SiC nanowires with totally excellent FE performances by increasing the emission sites and limiting the field screening effects.

The density of the nanowires is one of the key issues for their field emission (FE) properties of the nanoarrays, since it plays an important role on the electron emission sites and field screening effect. Here, we reported the nanowire-density-dependent FE properties of the n-type 3C-SiC nanoarrays. The highly oriented and large-scale SiC nanoarrays were grown on the 6H-SiC wafer via pyrolysis of polyureasilazane by adjusting the thicknesses of Au films used as the catalysts. The densities of the nanoarrays were tunable to be ∼2.9 × 107, ∼4.0 × 107, and ∼5.7 × 107 nanowires/cm2 by controlling the Au film thicknesses of 50, 70, and 90 nm, respectively. The measured FE characteristics disclosed that the turn-on fields of the samples could be tailored to be of ∼1.79, 1.57, and 1.95 V/μm with the increase of the densities, suggesting that a suitable nanowire density could favor the enhanced electron emission from the SiC nanoarrays with improved emission sites and limited field screening effects.

Flexible field emission (FE) emitters, whose unique advantages are lightweight and conformable, promise to enable a wide range of technologies, such as roll-up flexible FE displays, e-papers and flexible light-emitting diodes. In this work, we demonstrate for the first time highly flexible SiC field emitters with low turn-on fields and excellent emission stabilities. n-Type SiC nanoneedles with ultra-sharp tips and tailored N-doping levels were synthesized via a catalyst-assisted pyrolysis process on carbon fabrics by controlling the gas mixture and cooling rate. The turn-on field, threshold field and current emission fluctuation of SiC nanoneedle emitters with an N-doping level of 7.58 at.% are 1.11 V μm−1, 1.55 V μm−1 and 8.1%, respectively, suggesting the best overall performance for such flexible field emitters. Furthermore, characterization of the FE properties under repeated bending cycles and different bending states reveal that the SiC field emitters are mechanically and electrically robust with unprecedentedly high flexibility and stabilities. These findings underscore the importance of concurrent morphology and composition controls in nanomaterial synthesis and establish SiC nanoneedles as the most promising candidate for flexible FE applications. Spiky silicon carbide (SiC) ‘nanoneedles’ can improve light emission from e-paper and other bendable electronic devices. Flexible field-emission displays are an emerging technology in which tiny conductive tips grown on lightweight, rollable surfaces generate intense light. Significant manufacturing- and materials-related obstacles, however, have limited their application. Now, a team led by Tom Wu from King Abdullah University of Science and Technology in Saudi Arabia and Weiyou Yang from Ningbo University of Technology in China investigated how SiC — a compound with notable stiffness and stablity — performed as a field emitter by catalytically synthesising this material into nanoscale needles with ultrasharp tips and controllable doping levels on a carbon fabric surface. Their experiments showed that the SiC nanoneedles had low ‘turn-on’ field requirements and minimal emission fluctuations even after repeated bending cycles, thanks to their impressive mechanical robustness. We demonstrated for the first time highly flexible N-doped SiC nanoneedle field emitters with low turn-on fields and excellent emission stabilities. The characterizations of their field emission properties under repeated bending cycles and different bending states confirmed that such emitters are mechanically and electrically robust. These findings underscore the importance of concurrent morphology and composition controls in nanomaterial synthesis and establish SiC nanoneedles as the most promising candidate for flexible FE applications.

Understanding the roles of contacts and interfaces between metals and semiconductors is critically important for exploring nanostructure-based nanodevices. The present study shed some light on the dominated mechanism of size-dependent carrier transfer in the Schottky barrier diodes configured by the Pt-Ir/Si3N4-nanobelt/graphite (metal-semiconductor-metal (MSM)) sandwiched structure via a conductive atomic force microscopy using nanobelts with various thicknesses. The observed I-V behaviors suggested that the charge transports under the low and high biases were dominated by the reverse-biased Schottky barrier and space-charge-limited current (SCLC), respectively. The intermediate region between the low and high biases presented the transition between the Ohmic and SCLC behaviors, in which the ≡Si and =N dangling bonds acted as the defects within the Si3N4 nanobelt surface are predominant in the charge transfer.

While TiO2 nanoparticles are one of the most promising photocatalysts, their applications have been greatly hindered by easy aggregation. One of the effective routes to solve this problem is to incorporate them on/in a solid carrier. In this paper, we report the fabrication of hierarchically porous TiO2/SiO2 fibers via an electrospinning technique combined with subsequent high-temperature calcination treatment, in which the hierarchically porous SiO2 fibers confer a platform to assemble TiO2 nanoparticles with a uniform spatial distribution. The resultant hierarchically porous TiO2/SiO2 fibers have shown an enhanced photocatalytic activity with ∼95% degradation of rhodamine B as compared to ∼75% using our synthesized TiO2 nanoparticles and ∼77% using commercially available Degussa P25 after 120 min illumination.

The synthesis of hollow nanostructures has attracted great attention in nanotechnology. As compared to the long hollow structures, the short counterparts could serve other compelling applications, and have become a hotspot in the field of nanomedicine. In the present work, a novel brand graphite-based nanostructure with a special cup-shaped feature was synthesized via the pyrolysis of a solid carbon source of polymethylmethacrylate (PMMA). These nanocups are typically characterized with open ends, tapered hollow cavities and slowly convergent roots, which are free standing on the graphene films with very low length/diameter aspect ratios as compared to conventional carbon nanotubes. The growth mechanism of these cups was proposed. It is promising that the present graphite nanocups could have potential applications in drug delivery.

It is critically important to limit the oxidation of pure SiC in humid air, especially for mesoporous SiC with large surface areas. One of the effective routes is to introduce an inert outer layer around the surface of SiC to inhibit the formation of the SiOx oxides. In present work, we report the fabrication of mesoporous graphite/SiC hybrid fibers via electrospinning of the polymer precursors containing polyureasilazane, polyvinylpyrrolidone, cetyltrimethylammonium bromide and paraffin oil, combined with subsequent high-temperature pyrolysis treatment. The resultant fibers were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). It is found that the paraffin oil content has a profound effect on the growth of the fibers, enabling the fabrication of mesoporous graphite/SiC hybrid fibers with tunable structures and high purities. It is expected that the introduced graphite could significantly improve the surface properties of SiC mesoporous fibers, which could inspire and enhance their potential applications in photocatalysts and catalyst supports.

The purity and yield issues are significant challenges for the practical applications of nanoheterojunctions in functional devices. In the present work, we report the mass production of SiC/SiOx nanochain heterojunctions via pyrolysis of polymeric precursors. The as-synthesized nanochain heterojunctions were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The composition of the raw materials played a critically important role in the formation of SiC/SiOx nanochain heterojunctions. As compared to the reported works, our synthesized SiC/SiOx nanochain heterojunctions exhibit much higher purities with a very uniform size distribution and fascinating microstructures, which make them promising to be utilized as optoelectronic nanodevices.

In the present work, we report the growth of flexible SiC quasialigned nanoarrays with N dopants on carbon fabric substrate via the catalyst-assisted pyrolysis of a polymeric precursor. The resultant products are systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (EDS). The as-synthesized SiC nanowires are single-crystalline and grow along the [111] direction with a uniform spatial distribution of N dopants. The effect of the distance between the SiC array and the anode on the Field emission (FE) properties was investigated. FE measurements show that these N-doped SiC nanoarrays could be an excellent candidate for field emitters with very low turn-on fields of 1.90–2.65 V μm−1 and threshold fields of 2.53–3.51 V μm−1, respectively, which can be mainly attributed to the decrease of work function induced by the N dopants.

Doping of one-dimensional silicon carbide nanomaterials with tailored doping types and levels is highly required for their potential applications in functional nanodevices. In the present work, we have reported the synthesis of N-doped 3C–SiC nanowires via catalyst-assisted pyrolysis of polymeric precursors with Co(NO3)2 as the catalysts. The resultant products were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and energy spectrum (EDS). It was found that a relatively low partial pressure played a determined role on the introduction of N dopants into the SiC nanowires. The pyrolysis temperatures had a profound effect on the doping levels of N, enabling the tunable n-type doping of 3C–SiC nanowires. Current work suggests a facile technique for the synthesis of n-type SiC nanomaterials with a uniform spatial distribution of N dopants in a controlled manner, which could be useful for manufacturing optoelectric nanodevices.

We reported the piezoresistance behaviors of n-type 3C-SiC nanowires, which show that the present SiC nanowires could be an excellent candidate for building robust pressure sensors with high sensitivities.

Inhibiting the easy oxidation nature of SiC nanostructure surface is a challenge for its application in nanodevices. Here, we have demonstrated the fabrication of C-sheathed SiC nanocables via a designed chemical vapour deposition method, in which the use of a steel-hoop-like sample support favours the growth of SiC/C nanocables with surface modification of C coatings. The obtained SiC/C nanocables are systematically characterized by scanning electron microscopy, x-ray diffraction, transmission electron microscopy and Raman spectroscopy. The electrical property measurements suggest that the surface modification of SiC nanostructures by C coatings can not only modulate the SiC surface property from hydrophilic to hydrophobic, but also significantly enhance their electrical properties.

In this study, we demonstrate the unconventional vapor–liquid–solid (VLS) growth of amorphous SiO2 nanooctopuses. The SiO2 nanooctopuses were successfully synthesized by a simple water-assisted reaction on Si wafers. The obtained aggregates have been systematically characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. A novel VLS model has been proposed for the growth of SiO2 nanooctopuses based on the experimental observations and characterizations. The amorphous SiO2 nanooctopuses emit stable violet-blue light, implying their potential applications in photoelectronic devices.

We reported, for the first time, the piezoresistance behaviors of single p-type 6H-SiC nanowires. The results suggest that present p-type 6H-SiC nanowires could be an excellent candidate for the fabrication of robust and reliable stress sensors.