Delimited Polyacenes: Edge Topology as a Tool to Modulate Carbon Nanoribbon Structure, Conjugation, and Mobility

Carbon nanoribbons offer the potential of semiconducting materials that maintain the large charge-carrier mobilities of graphene. Here, starting with polyacene as a reference, we present a theoretical investigation as to how polycyclic aromatic hydrocarbons inserted into the polymer structure modulate the edge topology of the zigzag polyacene. The variations in edge topology, in turn, produce nanoribbon structures that have electronic properties that span insulators to narrow-gap semiconductors. Clear connections are made among foundational models in aromatic chemistry, namely, descriptions in terms of Clar formulas and bond-length alternation patterns, and the nanoribbon electronic, phonon, and charge-carrier mobility characteristics. These relationships, for systems that are synthetically feasible from bottom-up, solution-based approaches, offer a priori and rational design paradigms for the creation of new nanoribbon architectures.