Although state-of-the-art ambipolar polymer semiconductors have been extensively reported in recent years, highperformance ambipolar polymers with tunable dominant polarity are still required to realize on-demand, target-specific, high-performance organic circuitry. Herein, dithienyl-diketopyrrolopyrrole (TDPP)-based polymer semiconductors with engineered side-chains have been synthesized, characterized and employed in ambipolar organic field-effect transistors, in order to achieve controllable and improved electrical properties. Thermally removable tert-butoxycarbonyl (t-BOC) groups and hybrid siloxane-solubilizing groups are introduced as the solubilizing groups, and they are found to enable the tunable dominant polarity and the enhanced ambipolar performance, respectively. Such outstanding performance based on our molecular design strategies makes these ambipolar polymer semiconductors highly promising for low-cost, large-area, and flexible electronics.
Five core-dichlorinated naphthalene diimides (NDIs) bearing several fluoroalkyl-substituents at the imide nitrogens were
synthesized, characterized and employed in organic n-channel
thin-film transistors with a vacuum-deposited
semiconductor layer on 110 nm thick SiO<sub>2</sub> (100 nm)/AlO<sub>x</sub> (8 nm)/SAM (1.7 nm) and 5.7 nm thick AlO<sub>x</sub> (3.6 nm)/SAM
(2.1 nm) gate dielectrics. The electron mobility of the thin-film transistors under ambient conditions is as large as
1.3 cm<sup>2</sup>/Vs on the thicker gate dielectric. On the thinner gate dielectric the mobility is lower (0.4 cm<sup>2</sup>/Vs) but enables
switching at gate-source voltages of only 3V. Such outstanding performance together with the feasible synthetic access
to these compounds make these semiconductors highly promising for
low-cost, large-area, and flexible electronics.