On the Stabilization of Carbynes Encapsulated in Penta-Graphene Nanotubes: a DFT Study.

We carried out density functional theory calculations to investigate the electronic and structural properties of linear carbon chains (carbynes) encapsulated in armchair and zigzag penta-graphene (PGNT) nanotubes. Results showed that PGNTs-wrapped carbyne can present negative formation energies that tend to stabilize that encapsulated carbon chains. These chains were stabilized in their cumulene and polyyne forms, with slight dependence on tube diameter. As a general trend, the PGNT band structures are kept almost unchanged upon carbyne encapsulation. This finding indicates weak orbital interactions between the PGNT and the carbyne. No net charge was found in chains encapsulated on zigzag PGNTs. Schematic representation of a carbyne encapsulated in a pentagraphene nanotube.