Alkyl Chain Orientations in Dicyanomethylene‐Substituted 2,5‐Di(thiophen‐2‐yl)thieno‐[3,2‐b]thienoquinoid: Impact on Solid‐State and Thin‐Film Transistor Performance

Abstract A series of dicyanomethylene‐substituted 2,5‐di(thiophen‐2‐yl)thieno[3,2‐b]thieno‐quinoids, in which soluble alkyl chains (2‐decyltetradecyls) are substituted at different positions (namely, 2,2′‐positions (Compound 1); 3,3′‐ positions (Compound 2); 6,6′‐positions (Compound 3)), are strategically designed and successfully synthesized. The photophysical and electrochemical properties as well as molecular packing of these new compounds are thoroughly investigated. Thin film transistor measurements reveal that Compounds 1–3 display markedly different charge transport performance. The solution processed thin film transistors of Compound 2 exhibits the highest electron mobility of up to 0.22 cm² V⁻¹ s⁻¹ under ambient conditions, one and three orders of magnitude higher than those of Compounds 3 and 1, respectively, demonstrating the strong impact of alkyl chain orientations on transistor performance.