Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
ACS Appl Mater Interfaces. 2014 Oct 22;6(20):18098-103. doi: 10.1021/am504984z. Epub 2014 Oct 6.
Molecular packing motifs in solid states is the dominant factor affecting the n-channel organic field-effect transistors (OFETs). However, few systematic researches were performed in the different extensions of π-conjugated molecules with the uniform substitution effecting the molecular packing motifs. In this manuscript, OFET devices based on three latterally expanded rylene diimides end-functionalized with uniform 3-hexylundecyl substitution on the imide positions were systematically studied on the relationship of molecular stacking, film microstructure, and charge transport. As the π-conjugated systems expanded from doubly linked perylene diimide dimer (d-4CldiPDI, 1), triply linked perylene diimide dimer (t-4CldiPDI, 2), to hybrid array (NDI-PDI-NDI, 3), their corresponding molecular packing motifs exhibited a divide: the optimized molecular configuration became more planar and d (001) spacing distances became larger, which resulted in a larger π-π overlapping. Thus, an enhanced electron mobility was obtained. A typical n-channel field-effect characteristic was observed in thin film devices based on these molecules under ambient conditions. Especially, the hybrid system (3) with more planar and π-expanded aromatic backbone exhibited superior electron mobility approaching 0.44 cm(2) V(-1) s(-1) and on/off ratio of 10(6) after optimal annealing in this study.
在固态中，分子堆积模式是影响 n 通道有机场效应晶体管（OFET）的主要因素。然而，对于具有均匀取代效应的π共轭分子的不同延伸，很少有系统的研究来影响分子堆积模式。在本文中，我们系统地研究了基于三个侧链扩展的并苯二酰亚胺，其酰亚胺位置上具有均匀的 3-己基十一烷基取代，研究了分子堆积、薄膜微结构和电荷输运之间的关系。随着π共轭体系从双连接的并苯二酰亚胺二聚体（d-4CldiPDI，1）、三连接的并苯二酰亚胺二聚体（t-4CldiPDI，2）扩展到杂化阵列（NDI-PDI-NDI，3），它们相应的分子堆积模式表现出了一个分界线：优化后的分子构型变得更加平面，d（001）间距变大，导致更大的π-π重叠。因此，获得了更大的电子迁移率。在环境条件下，基于这些分子的薄膜器件表现出典型的 n 通道场效应特性。特别是，具有更平面和π扩展芳族主链的杂化体系（3）在本研究中经过最佳退火后，表现出优异的电子迁移率，接近 0.44 cm(2) V(-1) s(-1)，开关比为 10(6)。
