Rational molecular design for isoindigo-based polymer semiconductors with high ductility and high electrical performance
Rational molecular design for isoindigo-based polymer semiconductors with high ductility and high electrical performance
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具有高延展性和高电性能的异靛蓝聚合物半导体的合理分子设计
DOI：
10.1039/c9tc03263k
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发表时间：
2019
影响因子：
6.4
通讯作者：
Qiu Longzhen
中科院分区：
文献类型：
--
作者：
Tian Fengshou;Chen Han;Du Yuchang;Chen Junhui;Wang Xiaohong;Lu Hongbo;Cho Kilwon;Zhang Guobing;Qiu Longzhen
实现聚合物半导体的良好电性能和延展性一直是具有挑战性的。在这项工作中，一系列的异靛蓝衍生物为基础的共轭聚合物进行了研究，以更好地了解聚合物的主链和侧链结构对其电气和机械性能的影响。结果表明，在给体上引入烷基侧链可以显著提高异靛蓝基聚合物的力学性能，但由于烷基侧链的空间位阻作用，使薄膜的电学性能大大降低。在合成基于双（2-氧代吲哚啉-3-亚基）-苯并二呋喃二酮（BIBDF）的聚合物（PBIBDF-BT）的过程中，将强吸电子单元如苯并二呋喃二酮插入异靛蓝链中，显著提高了膜的电性能，而不降低其机械性能。在50%的拉伸应变下观察到PBIBDF-BT薄膜中的裂纹开始。此外，PBIBDF-BT薄膜表现出双极输运性质，在100%应变下电子和空穴迁移率均大于0.1 cm 2 V−1 s−1。结果表明，PBIBDF-BT性能的提高主要归因于其合适的分子结构。长烷基侧链显著增加了PBIBDF-BT薄膜的延展性，主链中强吸电子的BIBDF单元增强了局部聚集，导致迁移率显著增加。这些结果表明，通过合理的分子设计，可以同时提高共轭聚合物的力学和电学性能。
Achieving good electrical properties and ductility of polymer semiconductors has always been challenging. In this work, a series of isoindigo derivative-based conjugated polymers was studied in an effort to gain a better understanding of the influence of polymer main and side chain structures on their electrical and mechanical properties. The results suggested that the introduction of alkyl side chains onto the donors can significantly enhance the mechanical properties of isoindigo-based polymers; however, the electrical properties of the films greatly deteriorated due to the large steric hindrance by the chain. The insertion of strong electron-withdrawing units, such as benzodifurandione, into the isoindigo chain during the synthesis of a bis(2-oxoindolin-3-ylidene)-benzodifuran-dione (BIBDF)-based polymer (PBIBDF-BT) significantly boosted the electrical properties of the films without decreasing their mechanical properties. The crack onset in PBIBDF-BT thin films was observed at 50% tensile strain. In addition, PBIBDF-BT thin films exhibited bipolar transport properties with both electron and hole mobilities greater than 0.1 cm2 V−1 s−1 at 100% strain. It is found that the improvement of PBIBDF-BT performance is attributed to its proper molecular structure. The long alkyl side chains significantly increase the ductility of PBIBDF-BT thin films, and the strong electron-withdrawing BIBDF unit in the main chains enhances the local aggregation, resulting in a significant increase in mobility. These results indicate that the mechanical and electrical properties of conjugated polymers could simultaneously be improved through reasonable molecular design.