Torsional fracture of carbon nanotube bundles: a reactive molecular dynamics study.

Carbon nanotubes individually show excellent mechanical properties, being one of the strongest known materials. However, when assembled into bundles, their strength reduces dramatically. This still limits the understanding of their scalability.

Smooth gap tuning strategy for cove-type graphene nanoribbons.

Graphene is a carbon-based material with an extensive range of promising properties. Since it does not present a bandgap, graphene is not suitable for optoelectronic applications. One possible way to open a gap is achieved by reducing graphene to its nanoribbon (GNR) form.

Adsorption of carbon dioxide and ammonia in transition metal-doped boron nitride nanotubes.

Density functional theory calculations were carried out to analyze the performance of single-walled boron nitride nanotubes (BNNT) doped with Ni, Pd, and Pt as a sensor of CO and NH. Binding energies, equilibrium distances, charge transference, and molecular orbitals, as well as the density of states, are used to study the adsorption mechanism of the gas species on the surface of the nanotube. Our results suggest a considerable rise in the adsorption potential of BNNTs when the doping scheme is employed, as compared with adsorption in pristine nanotubes.

Charge Carrier Scattering in Polymers: A New Neutral Coupled Soliton Channel.

The dynamical scattering of two oppositely charged bipolarons in non-degenerate organic semiconducting lattices is numerically investigated in the framework of a one-dimensional tight-biding-Hubbard model that includes lattice relaxation. Our findings show that it is possible for the bipolaron pair to merge into a state composed of a confined soliton-antisoliton pair, which is characterized by the appearance of states within less than 0.1 eV from the Fermi level.

Dynamic Formation of Bipolaron-Exciton Complexes in Conducting Polymers.

The recombination dynamics of two oppositely charged bipolarons within a single polymer chain is numerically studied in the scope of a one-dimensional tight-binding model that considers electron-electron and electron-phonon (e-ph) interactions. By scanning among values of e-ph coupling and electric field, novel channels for the bipolaron recombination were yielded based on the interplay between these two parameters. The findings point to the formation of a compound species formed from the coupling between a bipolaron and an exciton.

Electron-phonon coupling effects on intrachain polaron recombination in conjugated polymers.

Based on a one-dimensional Su-Schrieffer-Heeger (SSH) model with electron correlation considered within the extended Hubbard model (EHM), we investigate the role played by electron-phonon coupling constant on intrachain polaron recombination in conjugated polymers. Our results suggest that a competition between external electric field and electron-phonon coupling on defining the behavior of the charge distribution of the system takes place. Whereas increasing electric field plays the role of destabilizing the charge carriers, an increase of the electron-phonon coupling has the opposite effect.