Structural and Charge-Transport Properties of a Liquid-Crystalline α,ω-Disubstituted Thiophene Derivative: A Joint Experimental and Theoretical Study

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• 作者：Vincent Lemaur ; Sad Bouzakraoui ; Yoann Olivier ; Patrick Brocorens ; Cdric Burhin ; Jamila El Beghdadi ; Ana Martin-Hoyas ; Alain M. Jonas ; Dana Alina Serban ; Alexandru Vlad ; Nicolas Boucher ; Julie Leroy
• 刊名：Journal of Physical Chemistry C
• 出版年：2010
• 出版时间：March 18, 2010
• 年：2010
• 卷：114
• 期：10
• 页码：4617-4627
• 全文大小：538K
• 年卷期：v.114,no.10(March 18, 2010)
• ISSN：1932-7455

文摘

We present a joint experimental and theoretical study of the structural and charge-transport properties of a liquid-crystalline α,ω-disubstituted oligothiophene derivative for application in organic field-effect transistors. The structural properties of the crystalline and smectic phases are investigated by atomic force microscopy, X-ray reflectometry, and X-ray diffraction. To complement these data, molecular mechanics calculations together with the simulation of X-ray diffraction spectra were performed to determine the relative positions of the molecules in the unit cell. The electrical characteristics of field-effect transistors based on the oligothiophene derivative were measured and compared in the crystalline and smectic phases. Although the silanation of the SiO₂ gate dielectric promoted a marked improvement in the charge-carrier mobilities in the crystalline phase, the expected suppression of grain boundaries in the liquid-crystalline phase was not unambiguously evidenced. The experimental results were further complemented by a detailed theoretical analysis of the electronic couplings governing the charge-transport properties on the molecular scale.