Synthesis and Characterization of Isoindigo[7,6-g]isoindigo-Based Donor–Acceptor Conjugated Polymers

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• 作者：Yu Jiang ; Yao Gao ; Hongkun Tian ; Junqiao Ding ; Donghang Yan ; Yanhou Geng ; Fosong Wang
• 刊名：Macromolecules
• 出版年：2016
• 出版时间：March 22, 2016
• 年：2016
• 卷：49
• 期：6
• 页码：2135-2144
• 全文大小：656K
• ISSN：1520-5835

文摘

Four donor (D)–acceptor (A) conjugated polymers with isoindigo[7,6-g]isoindigo ([3E,8E]-3,8-bis(2-oxoindolin-3-ylidene)-6,8-dihydroindolo[7,6-g]indole-2,7(1H,3H)-dione, DIID) as A-unit and thiophene derivatives as D-units were synthesized by Stille polycondensation. Optical and electrochemical properties of the polymers were studied by UV–vis–NIR absorption spectrometer and cyclic voltammetry. Compared with isoindigo-based analogues, the polymers display much broader absorption spectra (covering 400–950 nm) and remarkably lower bandgaps (ca. 1.3 eV). All polymers showed ambipolar transport properties as evaluated by bottom-gate/top-contact (BGTC) and top-gate/bottom-contact (TGBC) organic thin film transistors (OTFTs) in air. Gate-voltage-dependent hole mobility (μ_h) was observed for BGTC devices, while the mobility of TGBC devices exhibited weak gate-voltage dependence. P3 delivered the best device performance. At the optimized thermal annealing temperature (200 °C), a μ_h of 1.79 cm²/(V s) and an electron mobility (μ_e) of 0.087 cm²/(V s) were demonstrated with BGTC devices, and μ_h calculated from the higher V_GS region is decreased to 0.35 cm²/(V s). The relatively balanced hole and electron mobilities were observed for TGBC devices based on P3, which were 0.45 and 0.16 cm²/(V s), respectively.