High-Performance, Stable Organic Field-Effect Transistors Based on <i>trans</i>-1,2-(Dithieno[2,3-<i>b</i>:3′,2′-<i>d</i>]thiophene)ethene

We present here the synthesis, characterization, and transistor performance of three semiconductor materials based on <i>trans</i>-1,2-(dithieno[2,3-<i>b:</i>3′,2′-<i>d</i>]thiophene)ethene derivatives. Although the incorporation of aromatic, alkyl substituents in both ends of <i>trans</i>-1,2-(dithieno[2,3-<i>b:</i>3′,2′-<i>d</i>]thiophene)ethene have a negligible effect on the conjugation length and the energy gap, the subtle chemical modification leads to great variations in film microstructures, electronic properties, and packing arrangements. The appropriate substituents are capable of providing efficient molecular packing arrangements for high carrier mobility. The phenyl-substituted derivative, compound <b>3</b>, demonstrates a remarkably high thin film FET performance, with mobility up to 2.0 cm<sup>2</sup> V<sup>−1</sup> s<sup>−1</sup> and on/off ratio up to 10<sup>8</sup>. In addition, the devices show good environmental stability, even after storage in air for 7 months.