Dinaphthotetrathienoacenes: synthesis, characterization, and applications in organic field-effect transistors

The charge transport properties of organic semiconductors are limited by dynamic disorder that tends to localize charges in organic crystals. It is the main hurdle to overcome in order to significantly increase charge carrier mobility. We propose an innovative design that combines a chemical structure based on sulfur-rich thienoacene with a solid-state herringbone packing and present the synthesis, physicochemical characterization and charge transport properties of two new thienoacenes bearing a central tetrathienyl core fused with two external naphthyl rings: DN4T and isoDN4T. Both compounds crystallize with a herringbone pattern structure and present transfer integrals ranging from 33 to 99 meV (for the former) within the herringbone plane of charge transport. Molecular dynamics simulations point towards an efficient resilience of the transfer integrals to the intermolecular sliding motion commonly responsible for strong variations of the electronic coupling in the crystal. Best device performances were reached with DN4T with hole mobility up to μ = 2.1 cm² V-1 s-1 in polycrystalline OFETs, showing the effectiveness of the electronic coupling enabled by the new aromatic core. These promising results pave the way to the design of high-performing materials based on this new thienoacene, notably through the introduction of alkyl side-chains.