Flexible field-effect transistors from a liquid crystalline semiconductor by solution processes

We have fabricated the flexible field-effect transistors based on the liquid crystalline phenylterthiophene derivative via a solution process. A dielectric layer of polyvinyl alcohol (PVA) are deposited on a polyimide sheet substrate by a spin-coating method and then the thin film of 5-propyl-5′′-(4-pentylphenyl)-2,2′:5′,2′′-terthiophene is fabricated from its chlorobenzene solution on the dielectric layer by spin-coating or solution sheared deposition method. The fabricated devices exhibit good electrical performance with a hole mobility of up to 0.05 cm2 V−1 s−1 as well as excellent mechanical flexibility. The performance does not degrade at the external strain reached 3%. Our results demonstrate that liquid crystalline semiconductors are promising materials for low-cost flexible electronic devices.