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.