High Ambipolar Mobility in a Highly Ordered Smectic Phase of a Dialkylphenylterthiophene Derivative That Can Be Applied to Solution‐Processed Organic Field‐Effect Transistors

A phenylterthiophene derivative that exhibits a highly ordered smectic phase around room temperature is synthesized. In the bulk of the smectic phase, ambipolar carrier transport is observed and electron mobility exceeds 0.2 cm2 V–1 s–1. Thin-film transistors (see the AFM image in the figure) are fabricated by a spin-coating method and exhibit p-type operation, a field-effect mobility of 0.02 cm2 V–1 s–1, and an on/off ratio of 106.