Ultrahigh Mobility in Polymer Field-Effect Transistors by Design

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• 作者：Hoi Nok Tsao ; Don M. Cho ; Insun Park ; Michael Ryan Hansen ; Alexey Mavrinskiy ; Do Y. Yoon ; Robert Graf ; Wojciech Pisula ; Hans Wolfgang Spiess ; Klaus M眉llen
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：March 2, 2011
• 年：2011
• 卷：133
• 期：8
• 页码：2605-2612
• 全文大小：1081K
• 年卷期：v.133,no.8(March 2, 2011)
• ISSN：1520-5126

文摘

In this article, the design paradigm involving molecular weight, alkyl substituents, and donor鈭抋cceptor interaction for the poly[2,6-(4,4-bis-alkyl-4H-cyclopenta[2,1-b;3,4-b鈥瞉-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (cyclopentadithiophene鈭抌enzothiadiazole) donor鈭抋cceptor copolymer (CDT鈭払TZ) toward field-effect transistors (FETs) with ultrahigh mobilities is presented and discussed. It is shown that the molecular weight plays a key role in improving hole mobilities, reaching an exceptionally high value of up to 3.3 cm² V^鈭? s^鈭?. Possible explanations for this observation is highlighted in conjunction with thin film morphology and crystallinity. Hereby, it is found that the former does not change, whereas, at the same time, crystallinity improved with ever growing molecular weight. Furthermore, other important structural design factors such as alkyl chain substituents and donor鈭抋cceptor interaction between the polymer backbones potentially govern intermolecular stacking distances crucial for charge transport and hence for device performance. In this aspect, for the first time we attempt to shed light onto donor鈭抋cceptor interactions between neighboring polymer chains with the help of solid state nuclear magnetic resonance (NMR). On the basis of our results, polymer design principles are inferred that might be of relevance for prospective semiconductors exhibiting hole mobilities even exceeding 3 cm² V^鈭? s^鈭?.