Hierarchical Porous Intercalation-Type V2 O3 as High-Performance Anode Materials for Li-Ion Batteries.

As intercalation-type anode materials for Li-ion batteries (LIBs), the commercially used graphite and Li4 Ti5 O12 exhibit good cycling and rate properties, but their theoretical specific capacities are too low to meet the ever-growing demands of high-energy applications such as electric vehicles. Therefore, the development of new intercalation-type anode materials with larger capacity is very desirable. Herein, we design and synthesize novel 3 D hierarchical porous V2 O3 @C micro/nanostructures consisting of crumpled nanosheets, through self-reduction under annealing from the structurally similar VO2 (B)@C precursors without the addition of any other reducing reagent or gas. Excitingly, it is found for the first time through ex situ XRD technology that V2 O3 is a new, promising intercalation-type anode material for LIBs with a high capacity. V2 O3 @C micro/nanostructures can deliver a large capacity of 732 mAh g-1 without capacity loss at 100 mA g-1 even after 136 cycles, as well as exhibiting excellent cycling and rate performances. The application of V2 O3 for Na-ion batteries (NIBs) is elaborated for the first time, and excitingly, it is found that V2 O3 @C micro/nanostructures may be promising anode materials for NIBs.

Infrared photodetectors based on CVD-grown graphene and PbS quantum dots with ultrahigh responsivity.

Infrared photodetectors based on single-layer CVD-grown graphene and PbS quantum dots, which are fabricated by solution processing, show ultrahigh responsivities of up to 10(7) A/W under infrared light illumination. The devices fabricated on flexible plastic substrates have excellent bending stability. The photoresponse is attributed to the field-effect doping in graphene films induced by negative charges generated in the quantum dots.

n- and p-Type modulation of ZnO nanomesh coated graphene field effect transistors.

Periodic zinc oxide (ZnO) nanomeshes of different thicknesses were deposited on single-layer graphene to form back-gated field effect transistors (GFETs). The GFETs exhibit tunable electronic properties, featuring n- and p-type characteristics by merely controlling the thickness of the ZnO nanomesh layer. Furthermore, the effect of thermal strain on the GFETs from the substrate is suppressed by the ZnO nanomesh, which improves the thermal stability of the GFETs. This nanopatterning technique could modulate the electronic properties of the GFETs effectively.

Solvothermal synthesis and thermoelectric properties of indium telluride nanostring-cluster hierarchical structures.

A simple solvothermal approach has been developed to successfully synthesize n-type α-In2Te3 thermoelectric nanomaterials. The nanostring-cluster hierarchical structures were prepared using In(NO3)3 and Na2TeO3 as the reactants in a mixed solvent of ethylenediamine and ethylene glycol at 200°C for 24 h. A diffusion-limited reaction mechanism was proposed to explain the formation of the hierarchical structures. The Seebeck coefficient of the bulk pellet pressed by the obtained samples exhibits 43% enhancement over that of the corresponding thin film at room temperature. The electrical conductivity of the bulk pellet is one to four orders of magnitude higher than that of the corresponding thin film or p-type bulk sample. The synthetic route can be applied to obtain other low-dimensional semiconducting telluride nanostructures.PACS: 65.80.-g, 68.35.bg, 68.35.bt.

Inorganic salt-induced phase control and optical characterization of cadmium sulfide nanoparticles.

Phase-controlled synthesis of CdS nanoparticles from zinc-blende to wurtzite has been successfully realized by an inorganic salt-induced process with no use of surfactants or other ligands in an ultrasound-assisted microwave synthesis system. Pure zinc-blende CdS nanoparticles were produced without adding NaCl, while mixed zinc-blende and wurtzite nanoparticles were obtained by adding NaCl/Cd(2+) molar ratios below 1, and pure wurtzite nanoparticles were produced at a molar ratio of 1. The energy bandgap (E(g)) of the CdS nanoparticles calculated from optical absorption spectra increases as the phase transformation from zinc-blende to wurtzite occurs. Additionally, the CdS nanoparticles showed a 489 nm band-edge emission without adding NaCl, and a 501 nm emission when the molar ratios of NaCl to Cd(2+) are 0.25, 0.5 and 1. It was found that the phase transformation originates from the effect of the halide ion Cl(-). We also found that some other halide ions such as Br(-) and I(-) can induce the phase transformation. It is shown that the phase, size and optical properties of the anisotropic nanoparticles can be well tuned by varying the concentration of the halide ions.

Ultrasound-assisted microwave preparation of Ag-doped CdS nanoparticles.

Ag-doped CdS nanoparticles were synthesized by an ultrasound-assisted microwave synthesis method. The X-ray diffraction patterns reveal a structural evolution from cubic to hexagonal with increasing molar ratios of Ag(+)/Cd(2+) from 0% to 5%. It shows that the Ag-doped hexagonal CdS nanoparticles are polycrystal. The X-ray photoelectron spectroscopy of the CdS nanoparticles doping with 5% Ag(+) shows that the doped Ag in CdS is metallic. Simultaneously, the characteristic Raman peaks of the CdS nanoparticles enhance with increasing Ag(+) concentrations. The photocatalytic activity of different Ag-doped samples show a reasonable change due to different ratios of Ag which doped into CdS.