Elastic properties of carbon nanotubes and their heterojunctions

Comprehensive studies on the modelling and numerical simulation of the mechanical behaviour under tension, bending and torsion of single-walled carbon nanotubes and their heterojunctions are performed. It is proposed to deduce the mechanical properties of the carbon nanotubes heterojunctions from the knowledge of the mechanical properties of the single-walled carbon nanotubes, which are their constituent key unit

Separation of semi-conducting and metallic single-walled carbon nanotubes using a polytungstate

The present invention relates to a method for separating semi-conducting and metallic single-walled carbon nanotubes from each other and, if present, from other carbonaceous material, or for separating semi-conducting single-walled carbon nanotubes from other carbonaceous material, via centrifugation performed by a temperature of> 25°C using a solution of a polytungstate as sepa­ ration medium; to semi-conducting single-walled carbon nanotubes obtainable by this method; and to the use of these semi-conducting single-walled carbon nanotubes e.g. in electronic devices, optical devices, optoelectronic devices, energy storage devices and the like

Новые электропроводящие полимерные материалы, модифицированные углеродными нанотрубками

Conductive polymer composites (CPC) modified by single-walled carbon nanotubes were studied in this work. Loading single-walled carbon nanotubes into carbon black/polymer composites lowers both the percolation threshold and the volume resistivity of such composites. The a pplication of a small quantity of single-walled carbon nanotubes in carbon black/polymer composites allows reducing the carbon black content and improving the rheological and processing properties

Новые электропроводящие полимерные материалы, модифицированные углеродными нанотрубками

Conductive polymer composites (CPC) modified by single-walled carbon nanotubes were studied in this work. Loading single-walled carbon nanotubes into carbon black/polymer composites lowers both the percolation threshold and the volume resistivity of such composites. The a pplication of a small quantity of single-walled carbon nanotubes in carbon black/polymer composites allows reducing the carbon black content and improving the rheological and processing properties

Pyrene containing liquid crystalline asymmetric phthalocyanines and their composite materials with single-walled carbon nanotubes

In the present work we have studied the dispersion of single-walled carbon nanotubes in liquid crystalline asymmetrically substituted phthalocyanines (MPc, where M = = Cu, Co, and 2H) bearing one pyrene and six polyoxy groups as side chains. The influence of single-walled carbon nanotubes on the phase behavior of MPcs was investigated using X-ray diffraction, polarized optical microscopy and differential scanning calorimetry. It was demonstrated that the incorporation of small amounts of single-walled carbon nanotubes (≤ ≤ 1 wt.%) does not alter the MPc mesophases. The structural features and the sensor response of composite thin films of MPc with single-walled carbon nanotubes to ammonia vapor (10–50 ppm) was studied and compared with those of the films of pure MPc derivatives

Scanned Probe Microscopy of Electronic Transport in Carbon Nanotubes

We use electrostatic force microscopy and scanned gate microscopy to probe the conducting properties of carbon nanotubes at room temperature. Multi-walled carbon nanotubes are shown to be diffusive conductors, while metallic single-walled carbon nanotubes are ballistic conductors over micron lengths. Semiconducting single-walled carbon nanotubes are shown to have a series of large barriers to conduction along their length. These measurements are also used to probe the contact resistance and locate breaks in carbon nanotube circuits.Comment: 4 page

Spontaneous exciton dissociation in carbon nanotubes

Simultaneous photoluminescence and photocurrent measurements on individual single-walled carbon nanotubes reveal spontaneous dissociation of excitons into free electron-hole pairs. Correlation of luminescence intensity and photocurrent shows that a significant fraction of excitons are dissociating during their relaxation into the lowest exciton state. Furthermore, the combination of optical and electrical signals also allows for extraction of the absorption cross section and the oscillator strength. Our observations explain the reasons for photoconductivity measurements in single-walled carbon nanotubes being straightforward despite the large exciton binding energies.Comment: 4 pages, 3 figure

Large Magnetic Susceptibility Anisotropy of Metallic Carbon Nanotubes

Through magnetic linear dichroism spectroscopy, the magnetic susceptibility anisotropy of metallic single-walled carbon nanotubes has been extracted and found to be 2-4 times greater than values for semiconducting single-walled carbon nanotubes. This large anisotropy is consistent with our calculations and can be understood in terms of large orbital paramagnetism of electrons in metallic nanotubes arising from the Aharonov-Bohm-phase-induced gap opening in a parallel field. We also compare our values with previous work for semiconducting nanotubes, which confirm a break from the prediction that the magnetic susceptibility anisotropy increases linearly with the diameter.Comment: 4 pages, 4 figure