Electron transport through negatively curved nanographenes

Abstract

Pristine graphene exhibits unique physical and chemical properties. However, during its fabrication different imperfections are inevitably formed, which can induce changes to the properties of the material. Bottom-up methologies make it possible to synthesise graphene nanostructures incorporating selected defects in different positions. These graphene-like molecules of reduced size are being increasingly used, first as simple models to investigate the impact of different kind of structural defects, and secondly for achieving structures with selected properties for specific purposes. Some of these defects are able to induce curvature in the structure, but their impact on electron transport has scarcely been investigated. We report the first electron-transport study through saddle-shaped nanographenes, including experimental and theoretical perspectives. For the studied systems, we demonstrate that the inclusion of this kind of curvature by means of a tropone ring at the edge of the structure has no significant effect in terms of both single-molecule and self-assembled monolayer conductance, while enhancing solubility and processability considerably when compared to the defect-free analogues. These results aim at finding useful correlations between out-of-plane distortion on nanographenes and the electron transport through them, in view of the increasing interest in processable carbon nanostructures as potential candidates for the next generation of electronic technologies.