End Capping Does Matter: Enhanced Order and Charge Transport in Conjugated Donor鈥揂cceptor Polymers

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• 作者：Unsal Koldemir ; Sreenivasa Reddy Puniredd ; Manfred Wagner ; Sefaattin Tongay ; Tracy D. McCarley ; George Dimitrov Kamenov ; Klaus M眉llen ; Wojciech Pisula ; John R. Reynolds
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：September 22, 2015
• 年：2015
• 卷：48
• 期：18
• 页码：6369-6377
• 全文大小：567K
• ISSN：1520-5835

文摘

Optimized microstructure through control of both intra- and intermolecular interactions in organic semiconductors is critical for enhancing and optimizing charge transport for the realization of next-generation low-cost, mechanically flexible, and easy to process high performance, organic field effect transistors (OFETs). Herein, we report donor鈥揳cceptor alternating copolymers of dithienogermole (DTG) with 2,1,3-benzothiadiazole (BTD) and probe the importance of end groups on the control of molecular order and microstructure as it relates to the enhancement of charge carrier transport. Partial end-capping reactions, confirmed by ¹H NMR and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analyses, on the DTG鈥揃TD copolymer provided significant improvement in grazing incidence wide angle X-Ray scattering (GIWAXS) determined polymer ordering in thin films. Consequently, OFETs exhibited charge-carrier mobilities up to 0.60 cm²/(Vs) for the end-capped copolymer, which are an order of magnitude higher in comparison to the non-end-capped analogue, which displayed a mobility of 0.077 cm²/(Vs). We emphasize that a simple synthetic approach, the introduction of end-capping groups which remove reactive functionalities, can be effective in the development of next-generation OFET and solar materials by promising better control of the polymer organization.