Advanced Functional Materials, Vol.23, No.18, 2277-2284, 2013
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
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 13 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 V1 s1 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.