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Summary of the release

Researchers including Dr. Satoru Inoue and Prof. Tatsuo Hasegawa at Univ. of Tokyo, Group Director Koji Yonekura at RIKEN have developed high-performance liquid crystalline organic semiconductors in which molecular order and disorder coexist, and succeeded in characterizing the frozen liquid crystalline state of their ultrathin films by electron crystallography. This is performed as joint research with Assoc. Prof. Yasutomo Segawa at Institute for Molecular Science.

A liquid crystalline (LC) state is intermediate between solid and liquid. In the LC state, the orientation order of rod-shaped molecules in the long axis (longitudinal direction) coexists with disordered alignment in the transverse direction. A wide variety of molecular materials has LC states. In recent years, high-performance organic semiconductors have been obtained using rod-like molecules similar to those in LC materials. It has become clear that many of these semiconductors change to LC phases at high temperatures. Therefore, application of the excellent functions of LC materials for the advancement of organic semiconductors is attracting attention. However, the performance of these semiconductors is significantly degraded in the LC state. In the present study, researchers succeeded in developing high-performance LC organic semiconductors based on their versatile molecular design that controls the substituents of organic semiconductor molecules. Furthermore, researchers succeeded in characterizing the coexistence of molecular order and disorder in their LC organic semiconductors by electron crystallography with a state-of-the-art cryo-electron microscope.

Researchers published their results on December 22, 2021, in Chemistry of Materials.

Fig. (a) Structure and space filling model of the organic semiconductor developed in the present study.
(b). Disordered Layered-Herringbone phase of the organic semiconductor characterized by electron crystallography.

Information of the Paper

Authors: Satoru Inoue, Kiyoshi Nikaido, Toshiki Higashino, Shunto Arai, Mutsuo Tanaka, Reiji Kumai, Seiji Tsuzuki, Sachio Horiuchi, Haruki Sugiyama, Yasutomo Segawa, Kiyofumi Takaba, Saori Maki-Yonekura, Koji Yonekura, and Tatsuo Hasegawa

Journal Name: Chemistry of Materials

Journal Title: “Emerging Disordered Layered-Herringbone Phase in Organic Semiconductors Unveiled by Electron Crystallography”

DOI：10.1021/acs.chemmater.1c02793