Conformational Change of Alkyl Chains at Phase Transitions in Thin Films of an Asymmetric Benzothienothiophene Derivative
Conformational Change of Alkyl Chains at Phase Transitions in Thin Films of an Asymmetric Benzothienothiophene Derivative
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不对称苯并噻吩并噻吩衍生物薄膜中烷基链在相变时的构象变化
DOI：
10.1021/acs.jpclett.2c03399
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Hasegawa Takeshi
中科院分区：
文献类型：
--
作者：
Shioya Nobutaka;Yoshida Mariko;Fujii Masamichi;Shimoaka Takafumi;Miura Riku;Maruyama Shingo;Hasegawa Takeshi
在众多有前途的有机半导体材料中，2-癸基-7-苯基[1]苯并噻吩并[3，2-B][1]苯并噻吩（Ph-BTBT-C10）在有机场效应晶体管中表现出优异的器件性能。该化合物具有高度有序的液晶态，即，近晶E（SmE）相。虽然从结晶状态的SmE相的过渡被认为是伴随着熔化的烷基链，没有光谱证据已被发现到目前为止。在这项研究中，癸基链的构象变化在Ph-BTBT-C10薄膜的相变进行了分析，通过温度依赖性测量原位使用红外光谱。光谱分析表明，多晶薄膜具有潜在的构象无序（thegaucheconformer），其速率随着热处理变得更加明显。正如预期的那样，在高于SmE相的转变温度下观察到癸基链的熔融。本研究还发现了一些对液晶有机半导体相变敏感的关键谱带。
Among many promising organic semiconducting materials, 2-decyl-7-phenyl[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-C10) shows outstanding device performances for organic field-effect transistors. This compound has a highly ordered liquid crystalline state, i.e., the smectic E (SmE) phase. Although the transition from the crystalline state to the SmE phase is believed to accompany melting of the alkyl chains, no spectroscopic evidence has been found so far. In this study, the conformational change of the decyl chains in Ph-BTBT-C10films across the phase transition is analyzed by temperature-dependent measurements in situ using infrared spectroscopy. The spectral analysis reveals that the polycrystalline film has latent conformational disorder (thegaucheconformer), the rate of which becomes more pronounced with the heat treatment. As expected, melting of the decyl chains is observed above the transition temperature to the SmE phase. This study also highlights the discovery of some key bands sensitive to the phase transitions in liquid crystalline organic semiconductors.