Unified Understanding of Molecular Weight Dependence of Electron Transport in Naphthalene Diimide-Based n-Type Semiconducting Polymers
Unified Understanding of Molecular Weight Dependence of Electron Transport in Naphthalene Diimide-Based n-Type Semiconducting Polymers
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DOI：
10.1021/acs.chemmater.2c02357
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发表时间：
2022-10
影响因子：
8.6
通讯作者：
Duyen K. Tran;Amélie Robitaille;I. J. Hai;Chia-Chun Lin;Daiki Kuzuhara;T. Koganezawa;Y. Chiu;M. Leclerc;S. Jenekhe
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作者：
Duyen K. Tran;Amélie Robitaille;I. J. Hai;Chia-Chun Lin;Daiki Kuzuhara;T. Koganezawa;Y. Chiu;M. Leclerc;S. Jenekhe
电子传输对于在各种电子和光电器件中使用n型半导体聚合物至关重要。在此，我们结合联合收割机测量场效应电子迁移率和体电子迁移率与薄膜微结构表征，以阐明在n型半导体聚合物，例如萘二酰亚胺-双硒代共聚物，PNDIBS的电子传输的聚合物链长依赖。PNDIBS和其它n型半导体共聚物的体电子迁移率和场效应电子迁移率均在45-60个重复单元的临界聚合度（DPc）处出现峰值。低于DPcis的电子迁移率降低表明源于降低的晶间连接性，而高于DPc，链内扭曲/折叠，链间缠结和晶内限制主导电子传输。这些研究结果提供了一个统一的图片聚合物分子量对电子传输的影响，在萘二酰亚胺基聚合物，并提供了一个更定量的设计规则，高迁移率的n型聚合物与供体-受体架构。
Electron transport is critical to the use of n-type semiconducting polymers in diverse electronic and optoelectronic devices. Herein, we combine measurements of field-effect electron mobility and bulk electron mobility with thin-film microstructure characterization to elucidate the polymer chain length dependence of electron transport in n-type semiconducting polymers, exemplified by a naphthalene diimide-biselenophene copolymer, PNDIBS. Both bulk electron mobility measured by the space–charge limited current method and field-effect electron mobility of PNDIBS and other n-type semiconducting copolymers exhibit a peak at a critical degree of polymerization (DPc) of 45–60 repeat units. The decreased electron mobility below DPcis shown to originate from reduced intercrystallite connectivity while above DPc, intrachain twisting/folding, interchain entanglements, and intracrystallite limitations dominate electron transport. These findings provide a unified picture of the effects of polymer molecular weight on electron transport in naphthalene diimide-based polymers and offer a more quantitative design rule for high-mobility n-type polymers with donor–acceptor architecture.