Crystallization and Organic Field-Effect Transistor Performance of a Hydrogen-Bonded Quaterthiophene

Crystalline thin films of π-conjugated molecules are relevant as the active layers in organic electronic devices. Therefore, materials with enhanced control over the supramolecular arrangement, crystallinity, and thin-film morphology are desirable. Herein, it is reported that hydrogen-bonded substituents serve as additional structure-directing elements that positively affect crystallization, thin-film morphology, and device performance of p-type organic semiconductors. It is observed that a quaterthiophene diacetamide exhibits a denser packing than that of other quaterthiophenes in the single-crystal structure and, as a result, displays enhanced intermolecular electronic interactions. This feature was preserved in crystalline thin films that exhibited a layer-by-layer morphology, with large domain sizes and high internal order. As a result, organic field-effect transistors of these polycrystalline thin films showed mobilities in the range of the best mobility values reported for single-crystalline quaterthiophenes. The use of hydrogen-bonded groups may, thus, provide an avenue for organic semiconducting materials with improved morphology and performance.