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It is a highly relevant topic concerning how to improve the electrochemical performance of anode materials for the next generation lithium-ion batteries (LIBs). Herein, for the first time, we report a facile and controllable approach to modify MoS2 nanosheets, a typical 2D material, as an anode material for advanced LIBs via oxygen plasma engineering. An oxygen plasma treatment not only generates vacancies/defects but also incorporates heteroatom doping to form Mo–O–C bonds. This unique hybrid specialty enables the oxygen-plasma-treated MoS2 to achieve superior electrochemical performance with high reversible capacities, a long-term cycle life, and good rate capabilities. The plasma-assisted modification is believed to be applicable for other 2D materials as an efficient anode for energy storages.

Single-walled carbon nanotubes (SWNTs) grown by chemical vapor deposition (CVD) are widely used for fabrication of high-performance nanotube devices. However, the high-temperature growth is incompatible with the current complementary metal-oxide semiconductor (CMOS) technology. We demonstrate a low-temperature and direct deposition of the CVD-grown SWNTs. The nanotubes are synthesized by floating catalytic CVD technique and further carried by the flowing gas directly to the low- temperature area. Individual SWNTs have been successfully deposited on Si/ SiO2 substrates covered with a polymethylmethacrylate layer, which results in a suspended geometry of the nanotube in the fabricated devices. We subsequently investigate the electrical-transport properties of a representative small band gap nanotube, which exhibits an ambipolar feature with p-channel mobility up to 1410 cm 2 V −1 S −1 at room temperature. Furthermore, low- temperature measurements down to 4 K reveal different transport characteristics with the gate voltage biased near zero or at a large negative value, respectively.

The resistance of single-walled carbon nanotube (SWNT) bundles has been investigated by two-terminal measurements. We find that the time dependence of resistance (dR/dt) exhibits different behaviors at different currents. At low currents, a positive dR/dt is observed. However, dR/dt shows a negative sign when the applied current exceeds a critical current (I-c). I-c coincides with the current when the sample begins to emit light. The variation of dR/dt can be interpreted as the thermal effects owing to Joule heating in the SWNTs. Our lighting SWNTs sample has a small change in resistance and exhibits high stability.

One-dimensional structures of nitrogen-rich carbon nitride are synthesized via a thermal evaporation process. The C-N atomic rings (s-triazine and/or tri-s-triazine) present in the precursor remain stable during the thermal evaporation and vapor transfer. They act as basic building blocks during the microstructure assembly; thus ensuring a high nitrogen content in the final product.

Individual zinc oxide tetrapods were designed as multiterminal sensors by the e-beam lithography method. Different from double-terminal sensors, these sensors can give multiple responses to a single signal at the same time. The designed tetrapod devices were employed to detect light with different wavelength. The results indicate that they are remarkable optoelectronic devices, sensitive to ultraviolet light, and have advantages on distinguishing noises and increasing sensitivity. This should be helpful for weak signal measurements of nanodevices.

In this paper, we present a new insight into nonequilibrium electrodeposition. Owing to the nanoscale confinement effect of the template channels, the large overpotential leads to a highly nonequilibrium process and generates segmented metal-metal hydroxide one-dimensional (1D) nanostructures. The synthesized Ni-Ni(OH)x≈2 nanotubes vividly reflect the evolution of the local electrochemical environments, by which both the morphology and the composition have been modulated. The electrochemical mechanisms responsible for this unexpected deposition have been identified and discussed. It was exploited to obtain bi-segmented Ni nanowire-Ni(OH)x≈2 nanotube. This work opens the way to a versatile synthesis of metal-metal hydroxide 1D nanostructures that could be applicable for the integration of well-aligned metal-hydroxide nanostructures into large-scale energy-storage devices.

International audience; This work presents a simple method to generate ordered chromophore/dispersant nanoarrays through a pore-filling process for a nanoporous polymer template to enhance chromophore luminescence. Fluorescence results combining with the morphological evolution examined by scanning probe microscopy reveal that the enhanced luminescence intensity reaches the maximum intensity as the nanopores of the template are completely filled by the chromophore/dispersant mixture. The variation is attributed to nanoscale spatial effect on the enhanced mixing efficiency of chromophore and dispersant, that is, the alleviation of self-quenching problem, as evidenced by the results of attenuated total reflection Fourier transform IR spectroscopy combining with grazing incident wide-angle X-ray diffraction. The enhanced luminescence of the chromophore/dispersant nanoarrays driven by the nanoscale spatial effect is highly promising for use in designing luminescent nanodevices.

International audience; We successfully address the challenge of aligning single-walled carbon nanotubes (SWNTs) and conjugated polymer chains in composite nanofibers for enhancing their opto-electrical properties. A pore-filling template strategy has been developed to prepare such nanocomposites from SWNTs and poly(para-phenylene vinylene) (PPV) chains, with both species well-oriented aligned along the pore axis. Addition of the SWNTs leads to a remarkable increase in photocurrent of four orders of magnitude as compared to equivalent pristine PPV nanofibers. Further analysis indicates that the strong photocurrent enhancement is not simply an effect of alignment, but additionally benefits from alignment-enhanced interaction of polymer chains with SWNTs, as supported by density functional theory (DFT) calculations.

International audience; This work presents a simple method to generate ordered conjugated polymer nanoarrays through a pore-filling process for nanoporous polymer templates so as to enhance the efficiency of photoluminescence (PL). PL results combined with the morphological evolution examined by scanning probe microscopy revealed that the enhanced PL reaches maximum intensity as the template pores are completely filled by conjugated polymers. Polarized PL spectroscopy and grazing incidence Fourier transform infrared spectroscopy were used to determine the chain orientation of templated conjugated polymer; the spectroscopic results indicate a parallel chain orientation along the cylindrical direction of nanopores. The induced alignment of the polymer chains is attributed to a nanoscale spatial effect that increases the PL intensity and the lifetime of the conjugated polymer. The enhanced luminescence of nanostructured conjugated polymers is highly promising for use in designing luminescent nanodevices.

Silicon nanocomposite with various structures was designed to improve the water-retention ability of the proton exchange membrane for elevated temperature performance. The results show that the amorphous SiO(2) nanoparticles and SiO(2) nanocrystals with size of several nanometers have little influence on the membrane preparation and possess good water-retention of 5.82 similar to 7.11 wt% at temperature of 100 degrees C. The mesoporous SiO(2)/Nafion membrane, however, have large gas crossover of 5.54 mA cm(-2) because of the grain size increase during the crystallinity procedure. The results also demonstrate that the crystallinity of the silica in the membrane significantly increases the water-retention membrane stability. The amorphous SiO(2)/Nafion membrane has obvious performance decay after a soaked period in water for 20 days with a considerable silicon loss about 25.3%. However, with the crystallinity of the silica, the nanocrystals SiO(2)/Nafion membrane and the mesoporous SiO(2)/Nafion membrane have little OCV and power output decrease after the soaking period. The nanocrystals SiO(2)/Nafion membrane is most favorable PEM because the superiorities of outstanding initial performance and excellent durability. After the soaking period, the maximum power output still can achieve 451 mW/cm(-2) at condition of 100 degrees C and 50 RH%.

A novel approach based on Coulomb explosion has been developed to separate single-walled carbon nanotubes (SWNTs) from their bundle. With this technique, we can readily separate a bundle of SWNTs into smaller bundles with uniform diameter as well as some individual SWNTs. The separated SWNTs have a typical length of several microns and form a nanotree at one end of the original bundle. More importantly, this separating procedure involves no surfactant and includes only one-step physical process. The separation method offers great conveniences for the subsequent individual SWNT or multiterminal SWNTs device fabrication and their physical properties studies.

We have developed a low-cost and effective method to align single-walled carbon nanotubes (SWNTs) using a series of diamond wire drawing dies. The obtained SWNTs are highly dense and perfectly aligned. X-ray diffraction (XRD) indicates that the highly dense and perfectly aligned SWNTs (HDPA-SWNTs) form a two-dimensional triangular lattice with a lattice constant of 19.62 angstrom. We observe a sharp (002) reflection in the XRD pattern, which should be ascribed to an intertube spacing 3.39 angstrom of adjacent SWNTs. Raman spectra reveal that the radical breath mode (RBM) of SWNTs with larger diameter in the HDPA-SWNTs is suppressed compared with that of as-grown SWNTs. The HDPA-SWNTs have a large density, similar to 1.09 g/cm(3), and a low resistivity, similar to 2 m Omega cm, at room temperature, as well as a large response to light illumination.

We report the direct synthesis of strong, highly conducting, and transparent single-walled carbon nanotube (SWNT) films. Systematically, tests reveal that the directly synthesized films have superior electrical and mechanical properties compared with the films made from a solution-based filtration process: the electrical conductivity is over 2000 S/cm and the strength can reach 360 MPa. These values are both enhanced by more than 1 order. We attribute these intriguing properties to the good and long interbundle connections. Moreover, by the help of an extrapolated Weibull theory, we verify the feasibility of reducing the interbundle slip by utilizing the long-range intertube friction and estimate the ultimate strength of macroscale SWNTs without binding agent.

In this letter, individual ZnO tetrapod was designed as a multiterminal sensor. The gas-sensing properties of water and oxygen of the device have been investigated. We found that if water was preadsorbed on the device, the sensitivity of oxygen can be effectively enhanced; meanwhile, the response time can also be remarkably shortened. The mechanism of these phenomena, we propose, is the adsorption competition of the two kinds of molecules. Our results show that the preadsorption of appropriate gas can enhance the performance of the sensors, which is helpful for sensor designing.

Small zinc oxide tripodlike arms were assembled at the end of nanowires through thermal evaporation of zinc powder in a horizontal tube furnace. These arms are hundreds of nanometers in length, and they are tens of nanometers in diameter, similar to that of the based nanowires. High-resolution transmission electron microscopy investigation exhibits that they are wurtzite structure and have clear twin planes at the junction of the arms and the based nanowires. The growth mechanism, Raman, and photoluminescence properties were discussed.

Zinc oxide tetrapods were synthesized on a large scale through thermal evaporation of zinc powder with a vapor transportation deposition method. Scanning electron microscope images gave clear evidences of twin planes at the junction of the tetrapods. Photoluminescence and waveguide behaviors of a single tetrapod were demonstrated with a near-field scanning optical microscope.