Conducting [pi] Columns of Highly Symmetric Coronene, The Smallest Fragment of Graphene

• Published in: Chemistry : a European journal 2016-04, Vol.22 (17), p.6023
• Main Authors: Yoshida, Yukihiro, Isomura, Kazuhide, Kishida, Hideo, Kumagai, Yoshihide, Mizuno, Motohiro, Sakata, Masafumi, Koretsune, Takashi, Nakano, Yoshiaki, Yamochi, Hideki, Maesato, Mitsuhiko, Saito, Gunzi
• Format: Article
• Language: English
• Subjects: Cations; Charging; Chemistry; Conduction; Conductivity; Distortion; Doping; Electrical conductivity; Electrical resistivity; Electrochemistry; Electronic materials; Fragmentation; Graphene; Polycyclic aromatic hydrocarbons; Robustness; Stacking; Symmetry; Temperature effects
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201505023

Coronene, which is the smallest D6h-symmetric polycyclic aromatic hydrocarbon, attracts particular attention as a basic component of electronic materials because it is the smallest fragment of graphene. However, carrier generation by physical methods, such as photo- or electric field-effect, has barely been studied, primarily because of the poor π-conduction pathway in pristine coronene solid. In this work we have developed unprecedented π-stacking columns of cationic coronene molecules by electrochemical hole-doping with polyoxometallate dianions. The face-to-face π-π interactions as well as the partially charged state lead to electrical conductivity at room temperature of up to 3Scm-1, which is more than 10 orders of magnitude higher than that of pristine coronene solid. Additionally, the robust π-π interactions strongly suppress the in-plane rotation of the coronene molecules, which has allowed the first direct observation of the static Jahn-Teller distortion of cationic coronene molecules.