Tuning the carrier mobility and electronic structure of graphene nanoribbons using Stone–Wales defects

Abstract

In the last decade, surface-assisted reactions involving well-defined molecular precursors have led to the controlled assembly of several clean-edged and defect-free graphene nanoribbons. The recent realization of a bisanthene-like quantum dot with pairs of pentagon–heptagon, or Stone–Wales (SW), defects has been successfully achieved. Based on the similarity between the pristine and SW-defective bisanthene blocks, we propose a set of systems based on the concatenation of SW-bisanthene motifs and study their electronic properties using density functional theory. We demonstrate that nanoribbons with SW-defects preserve the semiconducting character of their pristine counterparts. Furthermore, noteworthy behaviors involving the frontier levels emerge, which affect carrier mobilities of both electrons and holes. We also investigate the electronic transport properties of nanojunctions composed by graphene nanoribbons with a localized distribution of SW-defects compatible with the geometry of the corresponding bisanthene-like blocks. Our simulations shown that the transmission spectrum is sensitive to the position and concentration of SW-defects.