Mixing‐Induced Orientational Ordering in Liquid‐Crystalline Organic Semiconductors
Mixing‐Induced Orientational Ordering in Liquid‐Crystalline Organic Semiconductors
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DOI：
10.1002/admi.202201789
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发表时间：
2022-10
影响因子：
5.4
通讯作者：
K. Nikaido;S. Inoue;R. Kumai;Toshiki Higashino;S. Matsuoka;S. Arai;T. Hasegawa
中科院分区：
文献类型：
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作者：
K. Nikaido;S. Inoue;R. Kumai;Toshiki Higashino;S. Matsuoka;S. Arai;T. Hasegawa
有机半导体(OSC)通常具有热致液晶(LC)相，分子取向有序性部分丧失。通过溶液过程形成临时液晶态有望促进基于印刷的器件的生产，尽管尚未开发出控制液晶态上的分子有序性的方法。在这里，证明了在环境条件下，使用具有高层状结晶度的不对称烷基化的OSCs可以控制长轴分子有序性。引入少量具有较长烷基链长的OSC分子，将长轴无序相转变为双层有序相，提高了晶体管的空穴迁移率。高温下向近晶LC相转变的熵分析表明，分子的长轴有序可以由层内触发器运动和通过LC相的核-核相互作用之间的平衡来驱动。拟议的LC中介解决方案处理为高端印刷电子产品铺平了道路。
Organic semiconductors (OSCs) often exhibit thermotropic liquid‐crystalline (LC) phases in which molecular orientational order is partially lost. The formation of a temporary LC state via a solution process is expected to promote printing‐based device production, although a method of controlling molecular ordering over LC states has not yet been developed. Here, it is demonstrated that long‐axis molecular ordering can be controlled under ambient conditions using unsymmetrically alkylated OSCs with high layered crystallinity. Introducing a small amount of OSC molecules with longer alkyl‐chain lengths leads to the conversion of the long‐axis disordered phase into a bilayer‐type ordered phase with improved hole mobility in the transistor characteristics. Analyses of the entropies of the transitions to the smectic LC phases at elevated temperatures demonstrate that the long‐axis molecular ordering can be driven by a balance between intralayer flip–flop motion and core–core interactions through LC phases. The proposed LC‐mediated solution processing paves the way toward high‐end printed electronics.