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s A facile solution deposition method using the etched Cu2O truncated octahedrons as the substrates has been successfully demonstrated for tailoring Ag/Cu2O heterostructures with excellent reproducibility, and Ag nanoparticles have been deposited on the surface of different Cu2O particles including freshly prepared Cu2O truncated octahedrons, the etched Cu2O truncated octahedrons, Cu2O cube assemblies and Cu2O octahedron assemblies. The obtained tailoring Ag/Cu2O heterostructures prepared by the etched Cu2O truncated octahedrons exhibits enhanced photocatalytic activity for the degradation of MB solution under visible-light irradiation, and the photocatalytic activity of tailoring Ag/Cu2O heterostructures was 3.1 and 5.7 times higher than those of the etched Cu2O truncated octahedrons and bare Cu2O truncated octahedrons. The enhanced photocatalytic activity of tailoring Ag/Cu2O heterostructures can be attributed to tailoring surface of Cu2O truncated octahedrons, the enhancement of UV–vis absorbance spectra and electron sink effect due to Ag nanoparticle deposition. The facilely prepared tailoring Ag/Cu2O heterostructure products are promising materials in fields such as photocatalytic and optoelectronic applications.

Herein, a simple and an environmentally friendly approach is developed to fabricate the novel MnO@C hierarchical structure, derived from Mn-based metal organic frameworks, which is explored as an anode material for lithium ion batteries. Remarkably, the MnO@C microsphere electrode delivers an outstanding, long cycling capacity of 596.3 mA h g−1 at 5C (1C = 765 mA g−1) after 1000 cycles, and an excellent rate performance of 380.1 mA h g−1 at 10C. The overall outstanding properties of the hierarchical MnO@C composite can be attributed to the success of a new strategy for dual structure design, which provides two pathways for effectively alleviating volume changes and enhancing conductivity based on in situ TEM electrochemical experiments and electrochemical impedance spectra. Both the poor conductivity and great volume changes of the MnO electrode material can be effectively improved in two ways: the porous carbon matrix confining the MnO nanoparticles, and the hierarchical nanorod-assembled architecture. The structures herein suggest new design concepts for metal oxide nanoarchitectures for high performance electrode materials in lithium ion batteries.

3D flower-like porous NiO architectures were synthesized via a facile and green method. When applied as an electrode material for supercapacitors, the as-prepared 3D flower-like porous NiO exhibited an outstanding electrochemical performance, such as a high specific capacitance (1609 F g−1 at 2 A g−1), and a long-term cycling stability (4.3% loss after 3000 cycles). The excellent electrochemical performance is mainly attributed to the morphology of the porous ultrathin nanosheets self-assembling into flower-like architectures, which facilitate fast and efficient diffusion of the electrolyte ions. Thus, it is expected that the 3D flower-like porous NiO can be a perspective electrode material for electrochemical energy storage applications.

In this report, a simple Kirkendall-based process using freshly prepared Cu2O microcubes as sacrificial templates has been successfully demonstrated for the fabrication of CuS hierarchical and hollow micro/nanocubes (HHCs). Individual CuS HHCs were assembled with plenty of nanosheet-like building units. CuS HHCs showed improved photocatalytic activity in the degradation of methylene blue (MB) in the presence of H2O2. Under visible light irradiation, the photocatalytic activity of CuS HHCs was 3.7 and 5.8 times higher than those of Cu2O/CuS and Cu2O, respectively. Furthermore, they also showed good recyclability in the visible region. It appears that the enhanced photocatalytic performance of the hierarchical and hollow micro/nanostructures can be ascribed to the synergetic effect of the efficient light harvesting and high surface area of the CuS HHCs. The facilely prepared CuS HHC products are promising materials in the fields of photocatalytic and optoelectronic applications.

A simple one-pot hydrothermal route has been demonstrated for the fabrication of 3D ZnO@hemimorphite zinc silicate (ZSO) core–shell nano-heterostructures on the Si substrate. Individual 3D ZnO@ZSO core–shell nano-heterostructures were assembled with many bundle-like branches, and each bundle-like branch was composed of the ZnO rod as the core and ZSO nanowires as the shell. The structure and composition of the 3D ZnO@ZSO nano-heterostructures could be varied with different reaction conditions and exhibit excellent reproducibility as well. In addition, a possible mechanism for the fabrication of 3D ZnO@ZSO nanohybrids was proposed, suggesting that heterogeneous nucleation played important roles in the formation of 3D nanostructures. The resultant 3D ZnO@ZSO nano-heterostructure films exhibited hydrophobic adhesive characteristic with a water contact angle of 142.1° and a high contact angle hysteresis, which held a great potential in surface wettability and other opto-electronic applications.

Nanosheet-assembled ZnO flower-like ensembles, urchin-like ZnO nanorod assemblies and ZnO nanorods, were synthesised by a facile solution-based route. The Zn2+:OH− molar ratio was adjusted to obtain ZnO with different morphologies. Scanning electron microscopy, X-ray diffraction and an ultraviolet spectrophotometer were used to observe the morphology, crystal structure and photocatalytic activity of obtained ZnO in detail. The flower-like ZnO ensembles composed of ultra-thin nanosheets exhibited a much better photocatalytic activity than ZnO in the other morphologies, and the decomposition efficiency was 90.26%. It can be concluded that the presence of the photocatalytic activity depends on the morphology of the ZnO samples.

A novel and facile synthetic route has been developed to fabricate porous SiO2-coated ultrasmall Se particles (Se@SiO2 nanospheres) as a drug delivery nanoplatform which combines Se quantum dots and doxorubicin (DOX) for efficient synergistic treatment of cancer cells.

A graphene-based device requires the graphene to have an ideal shape, structure, and orientation, and be large enough, to allow them to be formed into a new device. Here the joining of individual single-layer and multi-layer graphene is performed in a transmission electron microscope-scanning tunneling microscope (TEM–STM) holder inside a 200 kV field emission TEM. Attempts have been made to join individual graphene sheets (GSs) with the so-called “top-to-top” and “layer-to-layer” geometries by applying a voltage. In the two geometries, the “top-to-top” form has resulted in a seamless joining for both single-layer and multi-layer GSs. The as-joined GSs show the same excellent electrical and mechanical properties as those of the original GSs. Large Joule heating originating from the field emission current will cause atom diffusion and self-assembly and then rearrangement of carbon networks at the GS edge front. In this way individual GSs could be extended and mended with the so-called “top-to-top” geometries by applying a constant voltage, to meet the required and desired shape, size, configuration, and functions for a variety of the special micro/nano scaled devices.

Nanosheet-assembled ZnO flake-like ensembles were fabricated by a facile solution-based route. The morphology, size and micro/nanostructure of the ZnO flake-like ensembles were investigated in detail. X-ray diffraction and scanning electron microscopy indicated that all the ZnO flake-like ensembles with the porous features were composed of many nanosheets with a hexagonal wurtzite structure. After visible-light irradiation for 3 h, the as-obtained ZnO flake-like ensembles exhibited significantly high photocatalytic activity for decomposing malachite green, and the decomposition efficiency was 76.8 . All of which indicates that the ZnO flake-like ensembles could serve as a good candidate for the degradation of organic pollutants.

Hierarchical self-assembled 3-D ternary Zn 2 GeO 4 nanorods have been successfully synthesized using a simple hydrothermal method. They are formed by two basic parts: a 3-D crystal base and 1-D nanorods nucleated from this base. Mechanisms of this micro/nanostructure growth are suggested to be governed by the change of concentration of ammonia and the reaction time during the self-assembly process. Good crystal lattice quality and morphology were demonstrated by XRD, SEM and TEM analyses. The micro/nanostructures are expected to be promoted in construction of micro/nano-optoelectronic devices.

Photothermal ablation (PTA) therapy has attracted much interest in recent years as a minimally invasive alternative to conventional approaches, such as surgery and chemotherapy, for therapeutic intervention of specifi c biological targets. [ 1 , 2 ] In particular, near-infrared (NIR, λ = 700–1100 nm) laser-induced PTA, which converts NIR optical energy into thermal energy, has attracted increasing attention, because the NIR laser is absorbed less by biological tissues and the typical penetration depth of the NIR (such as 980 nm) light can be several centimeters in biological tissues. [ 3 , 4 ] A prerequisite for the development of the NIR laser-induced PTA is to gain access to biocompatible and effi cient photothermal coupling agents. As the well-known NIR photothermal conversion agents, gold (Au) nanostructures, including supramolecularly assembled nanoparticles, [ 5–8 ]

Large-scale and uniform ZnSe solid and hollow microspheres have been prepared via controllable self-assembly of ZnSe faceted nanocrystals under hydrothermal conditions. During the process, using the surfactant or not plays a key role in the ZnSe faceted nanocrystals' self-assembly into the ZnSe microspheres. Using PVP as the surfactant, the ZnSe monodisperse faceted shaped (including cubes, hexagons, and pentagons) nanocrystals with a diameter of ∼50 nm have been obtained; without using PVP surfactant, the ZnSe solid microspheres with a diameter of ∼3 μm have been achieved by the self-assembly of ZnSe faceted shaped nanocrystals; while using oleyl amine as the surfactant, which combines with N2 bubbles from the decomposition of N2H4·H2O, forming a new “soft-template”, the ZnSe hollow microspheres have been synthesized through as-called “soft-template” process. Meanwhile, hydrothermal temperature, time, and reducing agent have significant effects on the surface morphology of the ZnSe microspheres, i.e., a suitable temperature (e.g., 180 °C), longer reaction time, and using a small quantity of N2H4·H2O could be beneficial to the growth of the well-defined ZnSe faceted nanocrystals and their self-assembly into microspheres. A possible mechanism for the formation of ZnSe nanocrystals and their self-assembly into ZnSe microspheres has been proposed.

Large-scale synthesis of highly graphitic carbon nanotubes (with a diameter of ∼5−8 nm) from a thermal reaction of activated carbon and Bi2O3 powders, which was grown via a carbon-thermal reduction and Bi catalyzed vapor−liquid−solid process has been obtained. Individual carbon nanotubes were terminated with an onion-shaped carbon tip, which has never been observed in growth of a carbon nanotube. Field emitters made from the present carbon nanotubes exhibit excellent emission properties: they can be operated at a very large current density of ∼145 mA/cm2 at a low voltage of 5.5 V/μm, and possess a long period (>32 h) of high emission stability at a high emission current density of ∼9 mA/cm2 and under a constant applied voltage. These properties are equally important for high image quality in field emission display fabrication. Hence, as-fabricated CNTs could act as excellent electron emitters and have great potential application in field emission panel displays.

Combining thermal decomposition and evaporation of a mixed powder of SiO and SnO2 under careful temperature control resulted in SnO2 nanowires epitaxial growth on Si bicrystalline nanowires, forming new three layered radial Si–Si–SnO2 nanowire heterostructures, which the nature of interfacial regions and phase boundaries are different from the characteristics of axial composite nanowires. Each Si–Si–SnO2 composite nanowire has a uniform diameter along its whole length; the typical diameter of the nanowires ranges from 50 to 150 nm, and the diameters of Si bicrystalline nanowires and SnO2 nanowires within a nanowire heterostructure are ∼30–100 nm. These Si–Si–SnO2 nanowire heterostructures display unique intensive green luminescence emission compared to that of UV emissions of the near-band edge of SnO2.

The synthesis of the (rocksalt phase) single-crystal square-like cross-sectional MgS nanotubes via a thermal reaction process was reported for the first time in the family of II–VI sulfide semiconductors, which enriches the wide spectrum of diverse inorganic nanotubular structures. As-grown MgS nanotubes are structurally uniform single-crystals; an individual faceted tube is enclosed by four {020} crystal planes and grows along the [001] orientation. The MgS nanotubes exhibited efficient hydrogen-storage capacity of ∼ 2.2 wt% at room temperature under hydrogen pressure of 33.6 atm and one intensive cathodoluminescence emission band centered at ∼ 688 nm. The new concept established here will be very helpful in developing other types of Mg-based material nanotubes with high a hydrogen-storage capacity. Moreover, the MgS nanotubes' cavity could be filled with different semiconducting materials with various band gaps to give interesting electrical and optical nanodevices.

A prerequisite for designing and constructing wireless biological nanorobots is to obtain an electrical source that is continuously available in the operational biological environment. Herein the first preparation of 980-nm laser-driven photovoltaic cells (980LD-PVCs) by introducing of a film of rare-earth up-converting nanophosphors in conventional dye-sensitized solar cells is reported. Under the irradiation of a 980-nm laser with a power of 1 W, the visible up-converting luminescence of rare-earth nanophosphors can be efficiently absorbed by the dyes in 980LD-PVCs so that they exhibit a maximal output power of 0.47 mW. In particular, after being covered with 1 to 6 layers of pig intestines (thickness: ca. 1 mm per layer) as a model of biological tissues, 980LD-PVCs still possess a maximal output power of between 0.28 and 0.02 mW, which is efficient enough to drive many kinds of biodevices. This research opens up the possibility of preparing and/or developing novel electrical sources for wireless biological nanorobots and many other biodevices.

In situ electron-beam irradiation was performed in a transmission electron microscope to fabricate nanocrystals of IV−VI semiconducting lead chalcogenides PbE (E = S, Se, and Te) and low-melting-point metals (Zn, Ga, Sn, and Cd). The source powders consisting particles of 300−1000 nm in diameter were supported on a thin carbon (C) film. A convergent electron beam was focused on an individual particle, which caused partial melting and evaporation of the particle and subsequent nucleation and growth of new nanoparticles on the C film. These nanocrystals are structurally uniform and free of any linear and planar defect and do not have any other impurity contamination. The method is easy to set up and is low in cost and is very fast (several seconds to several minutes) in process. It is believed that this new method can also be employed to synthesize many other material nanocrystals and one-dimensional nanostructures, beyond semiconductors and (low melting point) metals, such as oxides and even sulfides and n...

A cooperative thermal decomposition route to large-scaled star-shaped α-MnS nanocrystals, which show novel magnetic properties, i.e., a high blocking temperature (275 K) and a large coercive field (1573 Oe), is reported.

Large scaled hexagonal prismatic sub-micro sized Mg crystals were grown by a vapor-liquid-solid process, and found to be sensitive to electron beam irradiation in transmission electron microscope imaging, making hollow prismatic MgO boxes.

The rational design and fabrication of more multi-component (material-combination) 3D hierarchical heterostructures for high-performance pseudocapacitor applications still remains a challenge. Herein, we have designed and synthesized a 3D hierarchical heterostructure of MnO2 nanosheets or nanorods grown on an Au-coated Co3O4 porous nanowall array, resembling a sandwich configuration of Co3O4@Au@MnO2, by a facial and controllable electrochemical deposition process. Due to their unique self-assembling architecture and characteristics including porous Co3O4 nanowalls, ultrathin MnO2 nanosheets, and a high conductivity Au layer sandwiched between them, each component provides a much-needed critical function for the efficient use of metal oxides for energy storage. The synthesized 3D hierarchical heterostructures exhibited favorable electrochemical performances, such as a high specific capacitances of 851.4 F g−1 at 10 mV s−1 and 1532.4 F g−1 at 1 A g−1, good rate performance and an excellent long-term cycling stability (almost no degradation after 5000 cycles), which are better than those of the reported Co3O4 or MnO2 based electrode materials, and thus could be considered as perspective materials for high-performance electrochemical capacitors.

Single-crystal α-MnO2 ultralong nanowires (∼40 μm in length, ∼15 nm in diameter), which were synthesized by a simple polyvinylpyrrolidone (PVP) assisted hydrothermal route, exhibited a better electrical conductivity, a highest specific capacitance of 345 F g−1 at a current density of 1 A g−1 with high rate capability (54.7% at 10 A g−1) and good cycling stability.

ZnO films composed of uniform three-dimensional (3D) hierarchical microstructures on the conductive glass were synthesized by a one-step polyethylene glycol-assisted hydrothermal route with excellent reproducibility. The morphology of the ZnO hierarchical structured films was controlled by adjusting hydrothermal reaction conditions, i.e., time, temperature, reactant concentration, Zn source and surfactant. A specific growth mechanism for the ZnO hierarchical microstructured films is proposed, and the hydrothermal time is found to be a crucial role in the formation of the hierarchical structures either from the initial nucleation and growth of the primary rods or secondary/tertiary nucleation and growth on the the column facets of the primary rods. As-fabricated ZnO films show a strong photoluminescence emission peak at 435 nm, and a superhydrophobic adhesive surface with a water contact angle of 154.1° and a high contact angle hysteresis.

The morphology-selective synthesis of well-aligned Cu2-xSe nanostructures including nanosheets, nanoribbons, and heterostructures on copper substrate has been achieved by a simple hydrothermal route; the micropatterned assembly of Cu2-xSe nanostructures has been realized using a copper grid to direct the growth on prescribed arbitrary patterns with unprecedented control and selectivity. The control experimental conditions, such as hydrothermal temperature and time, and concentration of NaOH have been found to be important parameters for the growth process of the Cu2-xSe nanostructures. So-called “coordination assembly” has shown to be dominant in the formation of the Cu2-xSe nanostructures, consisting of an initial nucleation and subsequent vertical growth on the copper substrate. The wettability properties of the Cu2-xSe nanostructures have been investigated, and the water contact angle from these nanostructured materials has been measured to be up to 160°, showing a superhydrophobicity. These results might provide a facile route for the preparation of novel micropatterned and high assemblies of nanostructures on other metal substrates (e.g.Al, Zn, Mg, etc.), for which a number of promising applications in microelectronic fields can be envisioned.

A series of ZnO three-dimensional (3D) structures, including flower-like, star-like, sphere-like and sea urchin-like morphologies, have been fabricated by a hydrothermal method without any catalyst or template. The morphologies of these ZnO structures can be conveniently controlled, by selecting the reactants and controlling the experimental conditions, with excellent reproducibility, and a specific mechanism for the formation is proposed. The ZnO 3D structures have a strong emission peak at 405 nm, and several weak emission peaks at 452, 467, 493, 541 and 568 nm, and a high sensitivity and selectivity for gas sensing of ethanol.

Using as-obtained ZnS–Si biaxial nanowires as templates, which were prepared via a thermal evaporation of a mixed powder of SiO and ZnS under controlled temperature, ZnO–Si biaxial nanowire heterostructures were achieved by a simple post-oxidation process. Each ZnO–Si composite nanowire has a uniform diameter along its whole length; the typical diameter of the nanowires ranges from 100 to 500 nm, and the diameters of Si- and ZnO-side sub-nanowires within a nanowire heterostructure are ∼50–250 nm. Significant enhancement of green luminescence compared to the ZnO nanowires has been observed from these ZnO–Si biaxial nanowire heterostructures, which may find the applications in short wavelength photoelectric devices, fluorescence labels, and biological detectors. The present template-assisted method demonstrated here could be a general approach of fabricating nanowire heterostructures made of Si-based materials.

Semiconducting nanotubes with well-controlled dimensions, compositions and crystal structures represent a new class of intriguing systems for detailed studies of structure–property relationships at the nanoscale and prospective functional applications. This article features recent research progress in the design of different synthetic routes towards important semiconducting nanotubes made of groupIV: silicon; groupIII–V: GaN, GaP, AlN, InN and InP, and groupII–VI: ZnO, ZnS, ZnSe, CdS and CdSe. The fabricated nanotubes possess desirable atomic structures, surfaces, morphologies and properties to meet the growing demands and specific requirements of new technologies.

A simple, efficient and unique method has been developed for coating uniform, thin and continuous graphitic carbon shields (or carbon nanotubes) on CdS nanowires. As-coated CdS nanowires have a diameter of ∼80–200 nm and a length ranging from several to tens of microns, and graphitic carbon shields are as thin as several nanometers. Both CdS nanowires and carbon shields are highly crystalline and uniformly structured. Cathodoluminescence spectra reveal that the intra-tube CdS nanowires have one intense emission at ∼522 nm and a weak emission at ∼496 nm. It is expected that the graphite-layered shields would effectively act as chemically and electrically stable protecting layers enhancing the stability of CdS nanowires in harsh environments and thus improving their performances in optical and optoelectronic devices.

Structurally uniform PbTe nanotubes with high crystal quality have been successfully synthesized via a thermal chemical reaction process. As-synthesized PbTe nanotubes displayed regularly rectangular or square faceted, tapered shape with a thickness as thin as ∼20–40 nm, and a length of several µm; each faceted PbTe nanotube is enclosed by four {100} crystal planes, and the tube axis is in the [100] direction; for a given tapered tube, the root reaches a diameter of ∼ 100–300 nm, and the tip size varies from several to tens of nanometers. Such special shape and available sizes can make the manipulations easier for use in scanning probes; a spacious internal tube cavity may be further filled with different materials leading to interesting thermoelectric nanodevices.

A simple hydrothermal route has been developed for the fabricating ZnO hierarchical micro/nanostructure with excellent reproducibility. SEM and TEM analysis show that the hierarchical rod is a single-crystal, suggesting that many single-crystal micro/nanorods are assembled into ZnO hierarchical micro/nanostructures. The morphologies of the hierarchical rods can be conveniently tailored by changing the reaction parameters. And we also found citric acid plays a crucial role in the formation process of ZnO micro/nanostructures. Room-temperature photoluminescence spectra reveals that the ZnO hierarchical micro/nanostructures have a strong emission peak at 440 nm and several weak emission peaks at 420, 471 and 541 nm, respectively.