Effects of fluorine substitution in quinoidal oligothiophenes for use as organic semiconductors
Effects of fluorine substitution in quinoidal oligothiophenes for use as organic semiconductors
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DOI：
10.1039/c9tc06598a
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发表时间：
2020-03
影响因子：
6.4
通讯作者：
Keitaro Yamamoto;Shin-ichiro Kato;Hanna Zajaczkowska;T. Marszalek;P. Blom;Y. Ie
中科院分区：
文献类型：
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作者：
Keitaro Yamamoto;Shin-ichiro Kato;Hanna Zajaczkowska;T. Marszalek;P. Blom;Y. Ie
调节π共轭分子的电子特性是有机半导体材料开发中的一个重要课题。 π-共轭骨架上的氟取代被认为是降低分子轨道能量的合理分子设计。然而，用于实现这一策略的醌型低聚噻吩的开发已经滞后。在这里，我们报告了对带有氟原子的双（二氰亚甲基）取代的醌型低聚噻吩衍生物的系统研究，以阐明氟取代对此类化合物的结构、性能和半导体特性的影响。实验和理论研究表明，这些分子中发生分子内 S-F 非共价相互作用，导致固定反构象的形成。电化学测量表明，与相应的非氟化醌型分子相比，这些化合物具有增强的电子接受特性。 X 射线衍射测量表明，由这些分子组成的薄膜具有高水平的结晶度。这些特性导致有机场效应晶体管 (OFET) 中出现 n 型传导，即使在环境条件下也是如此。此外，这些氟取代化合物与p型并五苯的混合物在OFET中表现出良好的双极性行为。这些结果表明氟取代的醌型低聚噻吩在有机半导体材料中具有广泛的应用潜力。
Tuning the electronic properties of π-conjugated molecules is an important subject in the development of organic semiconducting materials. Fluorine substitution on π-conjugated frameworks is recognized as a rational molecular design for lowering the molecular orbital energies. However, the development of quinoidal oligothiophenes to accomplish this strategy has lagged behind. Here, we report on a systematic study of bis(dicyanomethylene)-substituted quinoidal oligothiophene derivatives bearing fluorine atoms to clarify the influence of fluorine substitution on the structure, properties, and semiconducting characteristics of such compounds. Experimental and theoretical studies revealed that intramolecular S–F non-covalent interactions occur in these molecules, leading to the formation of fixed anti-conformations. Electrochemical measurements show that these compounds have increased electron-accepting characteristics compared to the corresponding non-fluorinated quinoidal molecules. X-ray diffraction measurements indicate that thin films that are made up of these molecules possess a high level of crystallinity. These properties lead to the appearance of n-type conduction in organic field-effect transistors (OFETs), even under ambient conditions. Furthermore, blends of these fluorine substituted compounds with p-type pentacene show good ambipolar behavior in OFETs. These results demonstrate that fluorine-substituted quinoidal oligothiophenes have broad potential for use in organic semiconducting materials.