Defect Analysis of High Electron Mobility Diketopyrrolopyrrole Copolymers Made by Direct Arylation Polycondensation

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• 作者：Sebastian Broll ; Fritz N眉bling ; Alessandro Luzio ; Dimitros Lentzas ; Hartmut Komber ; Mario Caironi ; Michael Sommer
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：October 27, 2015
• 年：2015
• 卷：48
• 期：20
• 页码：7481-7488
• 全文大小：463K
• ISSN：1520-5835

文摘

Defect structures in high-performance conjugated polymers are generally known but still challenging to characterize on a quantitative basis. Here, we present a detailed analysis of backbone topology of a series of copolymers PDPPTh₂F₄ having alternating dithienyldiketopyrrolopyrrole (DPPTh₂) and tetrafluorobenzene (F₄) units made by direct arylation polycondensation (DAP). In contrast to early expectations of unselective C鈥揌 activation during the DAP of monomers with multiple C鈥揌 bonds, detailed structure analysis by high-temperature ¹H NMR spectroscopy reveals well-defined and alternating backbones with a quantifiable amount of 0鈥?2% DPPTh₂ homocouplings as the only defect structure in the main chain. Homocoupled 鈭扗PPTh₂鈥揇PPTh₂鈥?structural units are additionally characterized by UV鈥搗is spectroscopy. While 鈭扗PPTh₂鈥揌 end groups are inert to other side reactions, 鈭扚₄鈥揃r end groups are weakly susceptible to both dehalogenation and reaction with toluene. However, despite the presence of DPPTh₂ homocouplings, high field-effect transistor electron mobilities up to 鈭?.6 cm²/(V s) are achieved. This study highlights both that DPPTh₂ homocouplings pose a prevalent structural defect in DPPTh₂-based conjugated polymers made by DAP and that a very simple four-step DAP protocol can yield materials with varying molar mass and excellent n-type transistor performance.