100 °C-Langmuir-Blodgett Method for Fabricating Highly Oriented, Ultrathin Films of Polymeric Semiconductors
100 °C-Langmuir-Blodgett Method for Fabricating Highly Oriented, Ultrathin Films of Polymeric Semiconductors
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100 °C-Langmuir-Blodgett 方法制造高取向超薄膜聚合物半导体
DOI：
10.1021/acsami.0c18349
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发表时间：
2020
影响因子：
9.5
通讯作者：
Ariga Katsuhiko
中科院分区：
文献类型：
--
作者：
Ito Masato;Yamashita Yu;Tsuneda Yukina;Mori Taizo;Takeya Jun;Watanabe Shun;Ariga Katsuhiko
Langmuir-Blodgett (LB) 和 Langmuir-Schaefer 技术促进了空气-水界面的热力学有利性，在该界面上可以通过微米或毫米级力学来操纵纳米级分子聚集。水性亚相的常规使用在可用温度和铺展材料方面存在限制。我们提出了用惰性、低蒸气压液体乙二醇代替水相的一般策略。作为需要高温工艺的代表性铺展材料，我们对半晶聚合物半导体进行了研究。我们成功地证明了聚合物半导体在使用 LB 槽加热至 100 °C 的乙二醇的整个表面上均匀分布，并自发形成多层。 X射线衍射、光谱和电荷传输测量等综合研究表明，高温LB过程中固态聚合物薄膜的势垒压缩产生了聚合物主链的单轴排列，平均二色性比约为8，电子传输随之变得高度各向异性。这项工作中提出的 LB 方法可用于在最终环境下沉积薄膜，例如低于 0 °C 或高于 100 °C，从而最大限度地减少亚相蒸气压的影响。
The Langmuir–Blodgett (LB) and Langmuir–Schaefer techniques facilitate thermodynamic favorability at an air–water interface, at which nanoscale molecular aggregations can be manipulated by micrometer- or millimeter-scale mechanics. The customary use of an aqueous subphase has limitations in the available temperature and spread materials. We present a general strategy to replace the aqueous subphase with an inert, low-vapor-pressure liquid, ethylene glycol. As a representative spread material that requires high-temperature processes, a semicrystalline polymeric semiconductor was investigated. We successfully demonstrated that the polymeric semiconductor spreads homogeneously across the entire surface of ethylene glycol heated to 100 °C using an LB trough, and spontaneously forms multilayers. Comprehensive studies such as X-ray diffraction, optical spectroscopy, and charge transport measurements revealed that barrier compression of solid-state polymer thin films during a high-temperature LB process produced uniaxial alignment of the polymer main chain with an averaged dichroic ratio of about 8, by which the electron transport concomitantly became highly anisotropic. The LB method presented in this work could be used to deposit thin films under ultimate environments,e.g., below 0 °C or above 100 °C, minimizing the effects of the vapor pressure of the subphase.