%0 Journal Article %T Copolymers of Bis-Diketopyrrolopyrrole and Benzothiadiazole Derivatives for High-Performance Ambipolar Field-Effect Transistors on Flexible Substrates %J - %D 2018 %R https://doi.org/10.1021/acsami.7b16516 %X We develop an ¡°acceptor dimerization¡± strategy by a bis-diketopyrrolopyrrole (2DPP) for an ambipolar organic semiconductor. Copolymers of 2DPP and benzothiadiazole (BTz) derivatives, P2DPP-BTz and P2DPP-2FBTz, are designed and synthesized. Both of the polymers exhibit narrow optical bandgaps of ca. 1.30 eV. The strong electron-withdrawing property of 2DPP results in low-lying lowest unoccupied molecular orbital (LUMO) energy levels of the polymers, improving the electron mobilities. 2D grazing incident X-ray diffraction and atomic force microscopy indicate that the P2DPP-BTz exhibits a small ¦Ð¨C¦Ð stacking distance of 3.59 £¿ and a smooth interface, thus promoting high mobility. To take full advantage of the flexibility of organic semiconductors, flexible field-effect transistors (FETs) were fabricated on poly(ethylene terephthalate) (PET) substrates. The FETs based on P2DPP-BTz show high performance with hole and electron mobilities of 1.73 and 2.58 cm2 V¨C1 s¨C1, respectively. Our results demonstrate that the 2DPP acceptor is a promising building block for high-mobility ambipolar polymers %U https://pubs.acs.org/doi/10.1021/acsami.7b16516