Single walled carbon nanotube (SWCNT) films are candidates for use as transparent electrodes, especially where low-cost, flexible materials are desired. Chemical doping is a critical step in fabricating conductive films as doping substantially decreases the sheet resistance within SWCNTs and at tube−tube junctions. Despite the importance of chemical doping, surprisingly little effort is devoted to developing doping chemistry. Concentrated acid solutions are typically used to dope SWCNT films. Although they are effective at reducing the sheet resistance of SWCNT films, this method is plagued by two critical drawbacks. The first is that concentrated acid baths, such as HNO3, are extremely harsh and will damage virtually any device technology. Second, the film resistance is unstable and rises dramatically over time. These drawbacks make implementation of SWCNT transparent, conducting films in technological applications extremely difficult. Here, we report an alternative doping scheme that utilizes a single-electron oxidant (triethyloxonium hexachloroantimonate) to effectively dope the SWCNT films. As evidenced by optical and electrical measurements, the compound effectively p-dopes SWCNT films. In addition to the effective doping, the resultant film resistance is stable over time. The films doped with triethyloxonium hexachloroantimonate outperform nitric acid doped films by a factor of 2.5 over time. This study introduces a new category of chemical dopants that yield stable, transparent, and conductive SWCNT films suitable for technological applications.

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separated, there are positive and negative charges generated on coated electrodes depending on the triboelectric polarity of those dielectric materials. Therefore, a perfect design for a triboelectric nanogenerator (TENG) can be achieved by choosing the most distinct materials in terms of triboelectric polarity as well as diminishing of the feature sizes of those materials down to nanometer scale for obtaining maximum contact area. [ 20 ] A list of the triboelectric materials in accordance with their polarity is presented in Table S1, Supporting Information. Working mechanisms of TENG devices are based on two mechanical motion modes, contact and sliding mode. [ 20 ] Recent studies reveal that the sliding mode has a better voltage output. [ 13 ] However, it requires a more complicated device design. The output voltage of TENGs is enhanced above 1 kV by using different material combinations and device geometries. [ 12 ] In this study, we constructed core-shell nanostructures (polyethersulfone (PES) is in the core and As 2 Se 3 is in the shell) for building a 3D TENG device ( Figure 1 a-6,a-7). Aluminum tape was used as a substrate and contact electrode for both polyetherimide (PEI) nanopillars and As 2 Se 3 core-shell nanostructures (Figure 1 a-1,a-5). Detailed information about the fabrication of the As 2 Se 3 core-shell nanostructures and the PEI nanopillars is given in the Supporting Information (see Figure S1). The fl uorination process used in the fabrication of the PEI nanopillars and surface modifi cation of the As 2 Se 3 nanostructures is given in Figure S2 in the Supporting Information. Figure S3 in the Supporting Information illustrates the fabrication process of the nanopillars.Our device can be stimulated by both motion and acoustic waves at different frequencies. We combined fl uorinated As 2 Se 3 kilometer-long core-shell nanostructures, which are produced using an iterative fi ber-drawing technique, with PEI nanopillars, which are produced by a template-based method for the construction of the contact mode TENG in a multilayer fashion. Our device has an output of maximum 1.23 mW direct current (DC) and 0.51 W peak power and can power parallel connected 38 LEDs simultaneously. Our chalcogenide-based TENG has maximum 396 V and 1.6 mA peak-to-peak output voltage and current, respectively. In addition, a fi nite element model is developed to explain contact electrifi cation between core-shell nanostructures and nanopillars using COMSOL Multiphysics. A perfect match between analytically calculated open-circuit voltage (OCV) and OCV measurement for a single layer generator was presented.To enhance the performance of triboelectric devices, there are two important parameters that play a major role in the selection of material combinations: the surface properties and triboelectric polarity. [ 20 ] Since the surface properties can be modifi ed using various techniques, the triboelectric polarity is Scavenging waste energy is an alternative prominent solution, which may play an important role regarding the wor...

We have investigated the behavior of single-walled carbon nanotubes and nanospheres (C(60)) under high hydrostatic pressure using Raman spectroscopy over the pressure range 0.2-10 GPa using a diamond anvil cell. Different liquid mixtures were used as pressure transmission fluids (PTF). Comparing the pressure dependence of the Raman peak positions for the nanotubes and the nanospheres in different PTF leads to the observation of a number of new phenomena. The observed shift in Raman peak position of both radial and tangential modes as a function of applied pressure and their dependence on the PTF chemical composition can be rationalized in terms of adsorption of molecular species from the of PTF on to the surface of the carbon nanotubes and/or nanospheres. The peak shifts are fully reversible and take place at a comparatively modest pressure (2-3 GPa) that is far below pressures that might be required to collapse the nanoparticles. Surface adsorption of molecular species on the nanotube or nanospheres provides a far more plausible rational for the observed phenomena than ideas based on the notion of tube collapse that have been put forward in the recent literature.

Thermal decomposition and y-pyrolysis of aluminum nitrate nonahydrate have been investigated by means of X-ray, IR, UV/VIS, TGA and DTA. All the experimental results obtained before and after y-ray irradiation elucidated the decomposition mechanism.

The near-field evanescent microwave microscope is based on a coaxial transmission line resonator with a silver-plated tungsten tip protruding through an end-wall aperture. The sensor is used to measure local dielectric properties of thin-film YBa2Cu3O7−δ deposited on three different SrTiO3 bi-crystal substrates having mismatch grain boundary angles of 3°, 6°, and 12°. The measurements in the superconducting state are below critical temperature at T = 79.4 K. The dielectric property of the superconductor within the near field of the tip frustrates the electric field and measurably changes the transmission line’s resonant frequency. The shift of the resonator’s frequency is measured as a function of tip–sample separation and associated changes in quality factor (ΔQ) image scans of the thin film are presented. A quantitative relationship between the real and imaginary parts of the local dielectric constant and the frequency shift using the method of images is established. The comparison between experimental data and theory based on this method is given and discussed. Raman measurements of the intergranular strain within the YBa2Cu3O7−δ thin film deposited on each SrTiO3 substrate in the region of the bi-crystal junction showed excellent correlation between grain boundary mismatch and induced grain boundary strain. Compressive strains normal to the a axis (i.e. tensile strains normal to the b axis) were detected across the grain boundary. The magnitude of induced strain as well as its spread away from the grain boundary increased as the mismatch angle increased.

Pure Na2S203.5H20 , was investigated carefully for its X-ray diffraction, IR-absorption spectra, UV/Vis-absorption spectra, thermogravimetric analysis, differential thermal analysis before and after various gamma ray absorbed doses. Results obtained were explained, compared and discussed in detail, leading to a mechanism for radiation damage in this system.

We present a wet-spinning technique capable of producing continuous polymer nanofibers. This method involves injecting a solvated polymer into a highly viscous moving medium through a microaperture. The extruded fiber moves in a predictable spiral path and is collected around a spinning mandrel which also serves to pull the extruded fiber away from the aperture. Semicontinuous, solid nanofibers of polyvinyl butyral were produced with diameters ranging from 10μmto400nm. Electron microscopy indicates that submicron fibers exhibit a ribbonlike morphology. The effect of different processing parameters on the fiber size and shape is discussed.