Fine-Tuning of Crystal Packing and Charge Transport Properties of BDOPV Derivatives through Fluorine Substitution
Fine-Tuning of Crystal Packing and Charge Transport Properties of BDOPV Derivatives through Fluorine Substitution
复制标题
通过氟取代微调 BDOPV 衍生物的晶体堆积和电荷传输特性
DOI：
10.1021/jacs.5b11114
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发表时间：
2015-12-23
影响因子：
15
通讯作者：
Pei, Jian
中科院分区：
文献类型：
--
作者：
Dou, Jin-Hu;Zheng, Yu-Qing;Pei, Jian
有机单晶中的分子堆积对其电荷输运性质有很大影响，但由于分子间相互作用复杂，很难预测和设计。在这项工作中，我们已经实现了系统的微调的单晶分子堆积的五个苯并二呋喃二酮为基础的低聚（对苯撑亚乙烯基）（BDOPV）为基础的小分子，通过纳入电负性氟原子的BDOPV骨干。虽然这些分子在它们的单晶中都表现出类似的柱堆积构型，但分子间位移和距离可以通过调节取代基氟原子的量和/或位置来显著改变。密度泛函理论计算表明，不同氟取代基引起的电荷分布或静电势的细微差异对调节BDOPV化合物的分子堆积起着重要作用。因此，用于电子转移的电子耦合可以从滑动叠层中的71 meV变化到近共面反平行叠层中的201 meV，导致BDOPV衍生物的电子迁移率从2.6增加到12.6 cm（2）V-1 s（-1）。五种分子的电子迁移率与LUMO能级没有表现出良好的相关性，表明电荷传输性质的明显差异是分子堆积的结果。我们的工作不仅提供了一系列高电子迁移率的有机半导体，而且还表明，除了简单地降低分子能级外，电子迁移率是微调单晶堆积模式的有效方法。
Molecular packing in organic single crystals greatly influences their charge transport properties but can hardly be predicted and designed because of the complex intermolecular interactions. In this work, we have realized systematic fine-tuning of the single-crystal molecular packing of five benzodifurandione-based oligo(p-phenylenevinylene) (BDOPV)-based small molecules through incorporation of electronegative fluorine atoms on the BDOPV backbone. While these molecules all exhibit similar column stacking configurations in their single crystals, the intermolecular displacements and distances can be substantially modified by tuning of the amounts and/or the positions of the substituent fluorine atoms. Density functional theory calculations showed that the subtle differences in charge distribution or electrostatic potential induced by different fluorine substitutions play an important role in regulating the molecular packing of the BDOPV compounds. Consequently, the electronic couplings for electron transfer can vary from 71 meV in a slipped stack to 201 meV in a nearly cofacial antiparallel stack, leading to an increase in the electron mobility of the BDOPV derivatives from 2.6 to 12.6 cm(2) V-1 s(-1). The electron mobility of the five molecules did not show a good correlation with the LUMO levels, indicating that the distinct difference in charge transport properties is a result of the molecular packing. Our work not only provides a series of high-electron-mobility organic semiconductors but also demonstrates that fluorination is an effective approach for fine-tuning of single-crystal packing modes beyond simply lowering the molecular energy levels.