title: Drastic difference in lifetimes of the charge-separated state of the formanilide-anthraquinone dyad versus the ferrocene-formanilide-anthraquinone triad and their photoelectrochemical properties of the composite films with fullerene clusters.
abstract: A long-lived charge-separated (CS) state, which can be observed even at 900 mus after laser excitation, has been attained in the formanilide-anthraquinone dyad (FA-AQ) in dimethyl sulfoxide, whereas the CS lifetime is shortened significantly to 20 ps in the ferrocene-formanilide-anthraquinone triad (Fc-FA-AQ). Such a drastic decrease in the CS lifetime by the addition of a ferrocene moiety to the FA-AQ dyad is ascribed to a decrease in the driving force of back electron transfer and an increase in the reorganization energy of electron transfer despite the longer charge-separation distance. The FA-AQ dyad and the Fc-FA-AQ triad have been employed as components of photovoltaic cells, where composite molecular nanoclusters of the FA-AQ dyad or the Fc-FA-AQ triad with fullerene (C60) are assembled onto a SnO2 electrode using an electrophoretic method. The composite films of the Fc-FA-AQ triad exhibit 10 times smaller values of an incident photon-to-photocurrent efficiency (IPCE) as compared with those of the FA-AQ dyad in accordance with a drastic decrease of the CS lifetime by addition of a ferrocene moiety to the FA-AQ dyad.
authors.affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency, Suita, Osaka 565-0871, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Okamoto
authors.forename: Taku
authors.initials: T
authors.lastname: Hasobe
authors.forename: Nikolai V
authors.initials: NV
authors.lastname: Tkachenko
authors.forename: Helge
authors.initials: H
authors.lastname: Lemmetyinen
authors.forename: Prashant V
authors.initials: PV
authors.lastname: Kamat
authors.forename: Shunichi
authors.initials: S
authors.lastname: Fukuzumi