Copolymers of Bis-Diketopyrrolopyrrole and Benzothiadiazole Derivatives for High-Performance Ambipolar Field-Effect Transistors on Flexible Substrates

• Published in: ACS applied materials & interfaces Vol. 10; no. 31; pp. 25858 - 25865
• Main Authors: Chen, Jinyang, Jiang, Yingying, Yang, Jie, Sun, Yunlong, Shi, Longxian, Ran, Yang, Zhang, Qingsong, Yi, Yuanping, Wang, Shuai, Guo, Yunlong, Liu, Yunqi
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 08.08.2018
• Subjects: field-effect transistor; bis-diketopyrrolopyrrole; ambipolar polymer; flexible substrate; “acceptor dimerization” strategy
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.7b16516

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 π–π stacking distance of 3.59 Å 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–1 s–1, respectively. Our results demonstrate that the 2DPP acceptor is a promising building block for high-mobility ambipolar polymers.