Bilayered Crystalline Organic Semiconductors for Solution-processed OFETs: Asymmetrically-substituted Smectic Liquid Crystal of Benzo[1,2-b:4,5-b′]dithiophene Derivatives

• Hao Wu

  Imaging Science and Engineering Research Center, Tokyo Institute of Technology, J1-2, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226-8503 , Japan

• Hiroaki Iino

  Imaging Science and Engineering Research Center, Tokyo Institute of Technology, J1-2, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226-8503 , Japan

• Jun-ichi Hanna

  Imaging Science and Engineering Research Center, Tokyo Institute of Technology, J1-2, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226-8503 , Japan

Abstract

Asymmetrically-substituted smectic liquid crystals with a small core of benzo[1,2-b:4,5-b′]dithiophene (BDT) substituted with monoalkyl and phenyl groups, 6-alkyl-2-phenyl-benzo[1,2-b:4,5-b′]dithiophene (Ph-BDT-Cn, n = 8, 14), were synthesized, and their mesomorphism and properties of crystalline films were characterized for solution-processed OFETs. Both compounds exhibited the SmE phase, and their crystalline films derived from SmE films exhibited the crystal-to-crystal transition from the monolayered crystals as-fabricated to the bilayered crystals when thermally annealed. The FET mobility was significantly enhanced by a factor of 2 to 10, accompanied with the phase transition to the bilayered crystals and reached up to 0.59 cm2 V−1 s−1 in spite of a small core of BDT. We discuss a new strategy of molecular design of soluble OFET materials behind the present results.

Journal

• Chemistry Letters

  Chemistry Letters 47 (4), 510-513, 2018-02-02

  Oxford University Press (OUP)

Keywords

• General Chemistry

Details

• CRID: 1360565169059443584
• NII Article ID: 130006638875
• DOI: 10.1246/cl.180066
• ISSN: 13480715
• ISSN: 03667022
• Web Site: https://academic.oup.com/chemlett/article-pdf/47/4/510/54818800/cl.180066.pdf
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