Efficient Tin-Free Route to a Donor鈥揂cceptor Semiconducting Copolymer with Variable Molecular Weights

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• 作者：Roman Tkachov ; Yevhen Karpov ; Volodymyr Senkovskyy ; Ivan Raguzin ; Jakob Zessin ; Albena Lederer ; Manfred Stamm ; Brigitte Voit ; Tetyana Beryozkina ; Vasiliy Bakulev ; Wei Zhao ; Antonio Facchetti ; Anton Kiriy
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：June 24, 2014
• 年：2014
• 卷：47
• 期：12
• 页码：3845-3851
• 全文大小：366K
• ISSN：1520-5835

文摘

For the fabrication of efficient photovoltaic devices and thin-film transistors, 蟺-conjugated polymers with high molecular weight are desirable as they frequently show superior charge transport, morphological, and film-forming properties. Herein, we present an extremely fast tin-free method to polymerize a naphthalene diimide-dithiophene-based anion-radical monomer in the presence of Pd catalyst having bulky and electron-rich tritert-butylphosphine ligands (Pd/P^tBu₃). With this method, the corresponding semiconducting polymer, PNDIT2 (also known as P(NDI2OD-T2 or N2200) with a molecular weight in excess of 1000 kg/mol can be obtained quickly at room temperature and at rather low catalyst concentrations. In general, molecular weights of resulting polymer can be regulated by reaction conditions (e.g., catalyst concentration and reaction time). Besides high molecular weight PNDIT2 (e.g., with M_N 350 kg/mol, 膼_M =2.9), PNDIT2 with moderate molecular weight (e.g., M_N 110 kg/mol, 膼_M = 2.3) and low molecular weight (e.g., M_W 12 kg/mol, 膼_M = 1.9), can also be obtained. It was found that thus-prepared PNDIT2 exhibits field-effect electron mobilities of up to 0.31 cm²/(V s), similar to the Stille-derived N2200 control polymer (up to 0.33 cm²/(V s)). Preliminary studies demonstrated that Pd/P^tBu₃ catalyst is remarkably efficient in polymerizing of other anion-radical monomers, such as isoindigo-, and diketopyrrolopyrrole-based ones, although conventional Ni and Pd catalysts (e.g., Ni(dppp)Cl₂, Ni(dppp)Cl₂, Pd(PPh₃)₄) failed to polymerize these monomers.