Han Moon Jong, Lee Don-Wook, Lee Eun Kyung, Kim Joo-Young, Jung Ji Young, Kang Hyunbum, Ahn Hyungju, Shin Tae Joo, Yoon Dong Ki, Park Jeong-Il
Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., Samsung-ro 130, Yongtong-gu, Suwon-si, Gyeonggi-do 16678, Republic of Korea.
ACS Appl Mater Interfaces. 2021 Mar 10;13(9):11125-11133. doi: 10.1021/acsami.0c22393. Epub 2021 Feb 25.
The control of molecular orientation and ordering of liquid crystal (LC) organic semiconductor (OSC) for high-performance and thermally stable organic thin-film transistors is investigated. A liquid crystalline molecule, 2-(4-dodecyl thiophenyl)[1]dibenzothiopheno[6,5-:6',5'-]-thieno[3,2-]thiophene (C12-Th-DBTTT) is synthesized, showing the highly ordered smectic X (SmX) phase, demonstrating molecular reorganization via thermal annealing. The resulting thermally evaporated polycrystalline film and solution-sheared thin film show high charge carrier mobilities of 9.08 and 27.34 cm V s, respectively. Atomic force microscopy and grazing-incidence X-ray diffraction analyses prove that the random SmA-like structure (smectic monolayer) is reorganized to the highly ordered SmA-like structure (smectic bilayer) of C12-Ph-DBTTT at the crystal-SmX transition temperature region. Because of the strong intermolecular interactions between rigid DBTTT cores, the thin film devices of C12-Th-DBTTT show excellent thermal stability up to 300 °C, indicating that LC characterization of conventional OSC materials can obtain high electrical performance as well as superior thermal durability.
研究了用于高性能和热稳定有机薄膜晶体管的液晶（LC）有机半导体（OSC）的分子取向和有序性控制。合成了一种液晶分子2-(4-十二烷基噻吩基)[1]二苯并噻吩并[6,5-:6',5'-]噻吩并[3,2-]噻吩（C12-Th-DBTTT），其呈现出高度有序的近晶X（SmX）相，证明了通过热退火实现分子重组。所得的热蒸发多晶膜和溶液剪切薄膜分别显示出9.08和27.34 cm² V⁻¹ s⁻¹的高电荷载流子迁移率。原子力显微镜和掠入射X射线衍射分析证明，在晶体-SmX转变温度区域，C12-Ph-DBTTT的随机类SmA结构（近晶单层）重组成高度有序的类SmA结构（近晶双层）。由于刚性DBTTT核之间存在强分子间相互作用，C12-Th-DBTTT的薄膜器件在高达300°C时表现出优异的热稳定性，这表明传统OSC材料的LC特性可以获得高电性能以及卓越的热耐久性。
