title: Geometries, Electronic Couplings, and Hole Dissociation Dynamics of Photoinduced Electron-Hole Pairs in Polyhexylthiophene-Fullerene Dyads Rigidly Linked by Oligophenylenes.
abstract: To shed a light on fundamental molecular functions of photoinduced charge conductions by organic photovoltaic materials, it is important to directly observe molecular geometries of the intermediate charges just after the photoinduced electron-transfer reactions. However, highly inhomogeneous molecular environments at the bulk heteojunction interfaces in the photoactive layers have prevented us from understanding the mechanism of the charge conductions. We have herein investigated orbital geometries, electronic couplings, and hole-dissociation dynamics of photoinduced charge-separated (CS) states in a series of poly(3-hexylthiophene)-fullerene linked dyads bridged by rigid oligo-p-phenylene spacers by using time-resolved EPR spectroscopy. It has been revealed that one-dimensional intramolecular hole-dissociations exothermically take place from localized holes in initial CS states, following bridge-mediated, photoinduced charge-separations via triplet exciton diffusions in the conjugated polymer-backbones. This molecular wire property of the photoinduced charges in solution at room temperature demonstrates the potential utility of the covalently bridged polymer molecules applied for the molecular devices.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kobe University , 1-1 Rokkodaicho, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Miura
authors.affiliation: Department of Molecular Engineering, Graduate School of Engineering, Kyoto University , Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Ran
authors.initials: R
authors.lastname: Tao
authors.affiliation: Department of Molecular Engineering, Graduate School of Engineering, Kyoto University , Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Shibata
authors.affiliation: Department of Molecular Engineering, Graduate School of Engineering, Kyoto University , Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Umeyama
authors.affiliation: Department of Chemistry, Graduate School of Science, Kobe University , 1-1 Rokkodaicho, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tachikawa
authors.affiliation: Department of Molecular Engineering, Graduate School of Engineering, Kyoto University , Nishikyo-ku, Kyoto 615-8510, Japan.|Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University , Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Imahori
authors.affiliation: Department of Chemistry, Graduate School of Science, Kobe University , 1-1 Rokkodaicho, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kobori