Center for Supramolecular Optoelectronic Materials, Department of Materials Science and Engineering , Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826 , Korea.
ACS Appl Mater Interfaces. 2019 Feb 27;11(8):8301-8309. doi: 10.1021/acsami.8b20168. Epub 2019 Feb 13.
We describe herein the comprehensive theoretical and experimental studies on the transistor mobility of organic semiconductors by correlating a two-dimensional (2D) intermolecular interaction with thin-film morphology and the electronic coupling structure. We developed a novel bis-lactam-based small molecule, 1,5-dioctyl-3,7-di(thiophen-2-yl)-1,5-naphthyridine-2,6-dione (C8-NTDT), with a 2D-type C-H···O═C intermolecular interaction along the in-plane directions of the crystal packing structure, which is characteristically different from the one-dimensional-type intermolecular interaction shown in the typical bis-lactam molecule of 2,5-dioctyl-3,6-di(thiophen-2-yl)pyrrolo[3,4- c]pyrrole-1,4-dione (C8-DPPT). Experimentally and theoretically, C8-NTDT exhibited more favorable thin-film morphology and an electronic coupling structure for charge transport because of its unique 2D intermolecular interactions compared with C8-DPPT. In fact, C8-NTDT exhibited a hole mobility of up to 1.29 cm V s and an on/off ratio of 10 in a vacuum-processed device. Moreover, the high solubility with the 2D electronic coupling structure of C8-NTDT enables versatile solution processing for device fabrication without performance degradation compared to the vacuum-processed device. As an example, we could demonstrate a hole mobility of up to 1.10 cm V s for the spin-coated devices, which is one of the best performances among the solution-processed organic field-effect transistors based on bis-lactam-containing small molecules.
我们通过将二维（2D）分子间相互作用与薄膜形态和电子耦合结构相关联，全面研究了有机半导体的晶体管迁移率。我们开发了一种新型的基于双内酰胺的小分子，1,5-二辛基-3,7-二（噻吩-2-基）-1,5-萘啶-2,6-二酮（C8-NTDT），其具有 2D 型 C-H···O═C 分子间相互作用，沿晶体堆积结构的面内方向排列，这与典型的双内酰胺分子 2,5-二辛基-3,6-二（噻吩-2-基）吡咯并[3,4- c]吡咯-1,4-二酮（C8-DPPT）中的一维型分子间相互作用明显不同。实验和理论上，与 C8-DPPT 相比，C8-NTDT 由于其独特的 2D 分子间相互作用，表现出更有利的薄膜形态和电荷传输的电子耦合结构。事实上，在真空处理的器件中，C8-NTDT 的空穴迁移率高达 1.29 cm V s ，开关比为 10。此外，C8-NTDT 具有较高的溶解度和 2D 电子耦合结构，可通过各种溶液处理方法进行器件制造，而不会像真空处理器件那样导致性能下降。例如，我们可以证明旋涂器件的空穴迁移率高达 1.10 cm V s ，这是基于双内酰胺小分子的溶液处理有机场效应晶体管中性能最好的之一。
