One-dimensional Carbon Chains Research Articles

Formation of atomic carbon chains from graphene nanoribbons

The formation of one-dimensional carbon chains from graphene nanoribbons is investigated using it ab initio molecular dynamics. We show under what conditions it is possible to obtain a linear atomic chain via pulling of the graphene nanoribbons. The presence of dimers composed of two-coordinated carbon atoms at the edge of the ribbons is necessary for the formation of the linear chains, otherwise there is simply the full rupture of the structure. The presence of Stone-Wales defects close to these dimers may lead to the formation of longer chains. The local atomic configuration of the suspended atoms indicates the formation of single and triple bonds, which is a characteristic of polyynes.

ROUTE TO STABLE CARBON CHAINS

OPENING UP the possibility of a new class of materials for carbon-based electronic devices, researchers in China and Japan have created stable, one-dimensional carbon chains up to 16 atoms long ( P...

Specific features of the optical absorption in carbon nanosystems with hydrogen

This paper reports on the results of experimental investigations of the optical absorption (in the wavelength range 200–1200 nm) by carbon-containing thin nanofilms formed on the surface of poly(vinylidene fluoride) upon its chemical functionalization. The optical spectra exhibit resonance absorption peaks in the photon energy range 2.5–3.0 eV. The IR absorption spectra contain lines attributed to the carbon-containing phase. The band structure, the density of states, and the optical constants of one-dimensional carbon chains with added hydrogen are calculated by the semiempirical tight-binding method. The results of the calculations are compared with the experimental optical spectra. It is demonstrated that the theoretical and experimental spectra are in satisfactory agreement.

Special features of valent states in one-dimensional carbon systems with hydrogen

In the paper, the results of calculations of electron dispersion and electronic state density in the valence band of one-dimensional carbon chains with attached hydrogen by the semiempirical method of strong bond are presented. It is demonstrated that the position of maxima in the valent state density on the energy axis changes as a function of the concentration of hydrogen attached to the chains. The influence of the chain conformation is investigated. A comparison with the experimental photoelectron spectra is carried out. Agreement between the calculated and experimental spectra is satisfactory.

Resonance Raman spectroscopy in one-dimensional carbon materials

Brazil has played an important role in the development and use of resonance Raman spectroscopy as a powerful characterization tool for materials science. Here we present a short history of Raman scattering research in Brazil, highlighting the important contributions to the field coming from Brazilian researchers in the past. Next we discuss recent and important contributions where Brazil has become a worldwide leader, that is on the physics of quasi-one dimensional carbon nanotubes. We conclude this article by presenting results from a very recent resonance Raman study of exciting new materials, that are strictly one-dimensional carbon chains formed by the heat treatment of very pure double-wall carbon nanotube samples.

The role of carbon in unexpected visco(an)elastic behavior of amorphous silicon oxycarbide above 1273 K

Polymer-derived silicon oxycarbide is ostensibly amorphous, yet we show that it exhibits high temperature anelasticity that has so far been seen only in crystalline structures. The time dependency, and the magnitude of strain recovery upon unloading, are non-linear. Indeed the pattern is reminiscent of polymers where viscoelasticity arises from the time dependent but recoverable movement of one-dimensional carbon chains that are intertwined and cross-linked to some degree. In analogy we propose that viscoelasticity in this polymer-derived ceramic arises from an intertwined network of two-dimensional graphene sheets.

A “Chemical-Scissors-Assemble” Route to Titanium Carbide Nanorods

Abstract By using tetrachloroethylene (C2Cl4), metallic titanium powders and N-containing nucleophilic solvents, such as ethylenediamine (en), pyridine and diethylamine as raw materials, a new strategy, called “chemical-scissors-assemble” route, is explored to prepare TiC nanorods, in which nucleophilic solvent attacks at the carbon in tetrachloroethylene to remove the chlorine groups and produce free C2, which can assemble into one-dimensional conjugate carbon chain clusters, and then react with Ti powders and result in a one-dimensional structure of TiC nanorods.