High-performance polymer tfts printed on a plastic substrate

High-performance poly (3-hexylthiophene) (P3HT) thin-film transistors array was fabricated on a plastic substrate by employing micro-contact printing process. The microcontact printing process, which uses a silicon elastomer stamp, enables the patterning of polymer layers without any photolithography process. As the gate dielectric, spun polyimide, and low-temperature ion-beam deposited silicon dioxide layers were used, forming a dual-layer structure. It is found out that the polymide layer improves the surface roughness of the dielectric and accordingly brings about enhanced device performance. Additionally, by using O₂ plasma treatment, both higher drain current and carrier mobility were obtained simultaneously. Changes in the surface states of the source-drain electrodes and the morphology of the dielectric are proposed to account for the observed improvements. Based on the experiments, we built a high-performance plastic-based P3HT transistors array including 0.02 cm² V ·s in carrier mobility and on/off current ratio about 10³ ~ 10⁴.