Ultrahigh Mobility in Polymer Field-Effect Transistors by Design
Ultrahigh Mobility in Polymer Field-Effect Transistors by Design
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DOI：
10.1021/ja108861q
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发表时间：
2011-03-02
影响因子：
15
通讯作者：
Muellen, Klaus
中科院分区：
文献类型：
--
作者：
Tsao, Hoi Nok;Cho, Don M.;Muellen, Klaus
本文介绍了聚[2，6-]的分子量、烷基取代基和给体-受体相互作用的设计范式（4，4-双-烷基-4H-环戊二烯并-[2，1-B（j）3，4 b ']-二噻吩）-alt-4，7-（2，1，3-苯并噻二唑）]（环戊二烯基噻吩-苯并噻二唑）给体-受体共聚物（CDT-BTZ）制备了具有高迁移率的场效应晶体管（FET）。结果表明，分子量在提高空穴迁移率方面起着关键作用，达到了高达3.3 cm（2）V-1 s（-1）的异常高的值。这一观察结果的可能解释是突出结合薄膜形态和结晶度。由此，发现前者不改变，而同时，结晶度随着不断增长的分子量而提高。此外，其他重要的结构设计因素，如烷基链取代基和聚合物主链之间的供体-受体相互作用，可能会影响分子间的堆叠距离，这对电荷传输至关重要，因此对器件性能至关重要。在这方面，我们第一次试图阐明相邻聚合物链之间的供体-受体相互作用的帮助下，固态核磁共振（NMR）。根据我们的研究结果，聚合物的设计原则推断，可能是相关的未来半导体表现出空穴迁移率甚至超过3厘米（2）V-1秒（-1）。
In this article, the design paradigm involving molecular weight, alkyl substituents, and donor-acceptor interaction for the poly[2,6-(4,4-bis-alkyl-4H-cyclopenta-[2, 1-b(j)3,4b']-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (cyclopentadithiophene-benzothiadiazole) donor-acceptor copolymer (CDT-BTZ) 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 cm(2) V-1 s(-1). 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-acceptor 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-acceptor 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 cm(2) V-1 s(-1).