title: Molecular and thin film properties of cobalt half-sandwich compounds for optoelectronic application.
abstract: The structure and electronic properties of a novel cobalt half sandwich complex of cyclopentadiene (Cp) and diaminonaphthalene (DAnap) [CpCo(DAnap)] are described and compared to the previously reported diaminobenzene derivative [CpCo(DAbnz)] in view of their potential for (opto)electronic device application. Both complexes show stable redox processes, tunable through the diaminoacene ligand, and show strong absorption in the visible region, with additional transitions stretching into the near infrared (NIR). CpCo(DAnap) crystallises with a particularly large unit cell (9301 Å3), comprising 32 molecules, with a gradual rotation over 8 molecules along the long c-axis. In the solid state the balance of the optical transitions in both complexes is reversed, with a suppression of the visible band and an enhancement of the NIR band, attributed to extensive intermolecular electronic interaction. In the case of CpCo(DAnap), highly crystalline thin films could be formed under physical vapor deposition, which show a photocurrent response stretching into the NIR, and p-type semiconductor behavior in field effect transistors with mobility values of the order 1 × 10-4cm2V-1s-1. The device performance is understood through investigation of the morphology of the grown films.
authors.affiliation: EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, UK. neil.robertson@ed.ac.uk.
authors.forename: Maxwell
authors.initials: M
authors.lastname: Reinhardt
authors.affiliation: Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, 464-8601, Nagoya, Japan. s.dalgleish@nagoya-u.jp and Department of Chemistry and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Japan.
authors.forename: Simon
authors.initials: S
authors.lastname: Dalgleish
authors.affiliation: Department of Chemistry and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Shuku
authors.affiliation: Department of Chemistry and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Japan.
authors.forename: Louisa
authors.initials: L
authors.lastname: Reissig
authors.affiliation: Department of Chemistry and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Japan.
authors.forename: Michio M
authors.initials: MM
authors.lastname: Matsushita
authors.affiliation: School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK.
authors.forename: Jason
authors.initials: J
authors.lastname: Crain
authors.affiliation: Department of Chemistry and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Awaga
authors.affiliation: EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, UK. neil.robertson@ed.ac.uk.
authors.forename: Neil
authors.identifier: http://orcid.org/0000-0002-9230-6124
authors.initials: N
authors.lastname: Robertson