title: Photoinduced electron transfer of platinum(II) bipyridine diacetylides linked by triphenylamine- and naphthaleneimide-derivatives and their application to photoelectric conversion systems.
abstract: The recently reported efficient charge-separated system based on bipyridine-diacetylide platinum(ii) complexes was applied to photoelectric conversion systems herein, based on the design and synthesis of two triads: MTA-Pt-NDISAc (3, MTA: dimethoxytriphenylamine, Pt: platinum(ii) complex, NDISAc: thioacetate derivative linked to naphthalenediimide) and MTA-Pt-MNICOOH (4, MNICOOH: naphthaleneimide-4-carboxylic acid). The charge-separated (CS) states of triads 3 and 5 (MOM-protected 4) were effectively generated by photo-induced electron transfer in both THF and toluene, although the rate of formation of the CS state from 5 was relatively slow in toluene. The lifetimes of these CS states were determined to be 730 ns in toluene and 61 ns (70%) and 170 ns (30%) as a double exponential decay in THF for 3, and 600 ns in toluene and 170 ns in THF for 5. The acetylthio group of triad 3 was exploited in the preparation of a self-assembled monolayer (SAM) on a gold surface. Photocurrent was detected upon irradiation of an electrochemical cell comprising Au/3/Na ascorbate/Pt, which was ascribed to the platinum(ii) complex based on the action spectrum. The carboxylic acid group of triad 4 facilitated adsorption on the TiO2 surface, and a dye-sensitized solar cell constructed based on FTO/TiO2/4/electrolyte (LiI-I2)/Pt exhibited a poor energy conversion efficiency (η = 0.20%) based on the incident photon-to-current conversion efficiency spectrum and the I-V curve. This poor efficiency may be derived from the bent molecular shape of 4, or may be due to a possible high energy barrier in the electron injection process through the adsorption site.
authors.affiliation: Graduate School of Science, Osaka City University, Sugimoto Osaka 558-8585, Japan. suzuki-s@sci.osaka-cu.ac.jp
authors.forename: Shuichi
authors.initials: S
authors.lastname: Suzuki
authors.forename: Yuma
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Mai
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authors.lastname: Tsubamoto
authors.forename: Ryoji
authors.initials: R
authors.lastname: Sugimura
authors.forename: Masatoshi
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authors.lastname: Kozaki
authors.forename: Kenshi
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authors.lastname: Kimoto
authors.forename: Munetaka
authors.initials: M
authors.lastname: Iwamura
authors.forename: Koichi
authors.initials: K
authors.lastname: Nozaki
authors.forename: Naoki
authors.initials: N
authors.lastname: Senju
authors.forename: Chiasa
authors.initials: C
authors.lastname: Uragami
authors.forename: Hideki
authors.initials: H
authors.lastname: Hashimoto
authors.forename: Yohei
authors.initials: Y
authors.lastname: Muramatsu
authors.forename: Akinori
authors.initials: A
authors.lastname: Konno
authors.forename: Keiji
authors.initials: K
authors.lastname: Okada