Light-Harvesting and Photocurrent Generation by Gold Electrodes Modified with Mixed Self-Assembled Monolayers of Boron−Dipyrrin and Ferrocene−Porphyrin−Fullerene Triad

Imahori, Hiroshi; Norieda, Hiroyuki; Yamada, Hiroko; Nishimura, Yukio; Yamazaki, Iwao; Sakata, Yoshiteru; Fukuzumi, Shunichi

doi:10.1021/ja002154k

Cited by 423 publications

(296 citation statements)

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“…T o construct nanoscale devices or molecular wires that efficiently convert photon energies to chemical potentials, extensive studies have produced photoinduced, long-distance charge separation (CS) states by using donor (D)-acceptor (A)-linked multiarray systems that mimic natural photosynthesis (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11). In each intramolecular, sequential electron transfer (ET) step, an electron or a hole tunnels between D and A over substantial distances (Ͼ10 Å) as in the natural photosynthetic reaction centers (12).…”

mentioning

confidence: 99%

Primary charge-recombination in an artificial photosynthetic reaction center

Kobori

Yamauchi

Akiyama

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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101

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Photoinduced primary charge-separation and charge-recombination are characterized by a combination of time-resolved optical and EPR measurements of a fullerene-porphyrin-linked triad that undergoes fast, stepwise charge-separation processes. The electronic coupling for the energy-wasting charge recombination is evaluated from the singlet-triplet electronic energy gap in the short-lived, primary charge-separated state. The electronic coupling is found to be smaller by Ϸ40% than that for the primary charge-separation. This inhibition of the electronic interaction for the charge-recombination to excited triplet state largely results from a symmetry-broken electronic structure modulated by configuration interaction between 3 (b1u,b3g) and 3 (au, b3g) electronic states of the free-base porphyrin.electronic coupling ͉ long-range electron transfer ͉ molecular orbital symmetry T o construct nanoscale devices or molecular wires that efficiently convert photon energies to chemical potentials, extensive studies have produced photoinduced, long-distance charge separation (CS) states by using donor (D)-acceptor (A)-linked multiarray systems that mimic natural photosynthesis (1-11). In each intramolecular, sequential electron transfer (ET) step, an electron or a hole tunnels between D and A over substantial distances (Ͼ10 Å) as in the natural photosynthetic reaction centers (12). From Marcus theory (13)(14)(15)(16)(17)(18)(19)(20), the ET rate constant (k ET ) is described (in the weak coupling regime) aswhere -h is Planck's constant divided by 2 and V, the electronic coupling matrix element, represents the electronic tunneling interaction between D and A. FCWDS denotes Franck-Condon weighted density of states parameterized by the reorganization energy ( ) and the driving force (Ϫ⌬G) for the ET reaction. The FCWDS term is given by (4where k B is the Boltzmann constant and T is the temperature. Although for several long-range ET systems, V has been interpreted in terms of a superexchange coupling model (21) that bridges the redox sites (22-28), much remains to be resolved regarding the tunneling mechanism (29-34). In addition, characterizations of V will be useful for designing molecular electronic devices (35). Key to efficient photoinduced CS is prevention of the energywasting charge recombination (CR) characterized in part by V. Although V and have been investigated for various ET steps by experimentally measuring k ET s in systems such as D 2 -D 1 -A triad (7, 9, 36) and protein complexes (24,25,34), primary CR,-A has escaped elucidation, especially in the efficient stepwise CS systems because the CR kinetics is hidden by subsequent CS processes,In the photosynthetic reaction center protein of Rhodobacter sphaeroides, which contains as cofactors a special pair (P), two bacteriopheopheophytins (H A and H B ), and two quinones (Q A and Q B ), the CR kinetics of the primary CS state of P ؉• H A Ϫ• Q A cannot easily be observed, because H A Ϫ• 3 Q A forward ET (Ϸ200 ps) is much faster than the primary CR (10-20 ns, which has b...

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mentioning

confidence: 99%

Primary charge-recombination in an artificial photosynthetic reaction center

Kobori

Yamauchi

Akiyama

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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101

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“…C 60 SAMs [557] offer unique and attractive features for their use in advanced electronic device applications [647], for example, monolayers of C 60 derivatives on Au, ITO, or other substrates [648][649][650][651][652][653][654][655] have been investigated extensively in the recent past. Besides C 60 monolayer on Au, there are only a few reports about them on SiO 2 surfaces [346,[656][657][658][659][660][661][662][663] that are especially important for OFETs.…”

Section: Sams In Os Devicesmentioning

confidence: 99%

Organic semiconductors for device applications: current trends and future prospects

Ahmad

2014

Journal of Polymer Engineering

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Abstract:With the rich experience of developing silicon devices over a period of the last six decades, it is easy to assess the suitability of a new material for device applications by examining charge carrier injection, transport, and extraction across a practically realizable architecture; surface passivation; and packaging and reliability issues besides the feasibility of preparing mechanically robust wafer/substrate of single-crystal or polycrystalline/ amorphous thin films. For material preparation, parameters such as purification of constituent materials, crystal growth, and thin-film deposition with minimum defects/ disorders are equally important. Further, it is relevant to know whether conventional semiconductor processes, already known, would be useable directly or would require completely new technologies. Having found a likely candidate after such a screening, it would be necessary to identify a specific area of application against an existing list of materials available with special reference to cost reduction considerations in large-scale production. Various families of organic semiconductors are reviewed here, especially with the objective of using them in niche areas of large-area electronic displays, flexible organic electronics, and organic photovoltaic solar cells. While doing so, it appears feasible to improve mobility and stability by adjusting π-conjugation and modifying the energy bandgap. Higher conductivity nanocomposites, formed by blending with chemically conjugated C-allotropes and metal nanoparticles, open exciting methods of designing flexible contact/interconnects for organic and flexible electronics as can be seen from the discussion included here.

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“…A previously described method was used (Imahori et al, 2001). Briefly, a solution of 2-quinolinethiol (76 mg, 0.47 mmol) and NaOMe (25 mg, 0.47 mmol) in MeOH (10 mL) was stirred for 30 min at r.t.…”

Section: Mt-bdp-sh (1) Synthesismentioning

confidence: 99%

A BODIPY-embedding miltefosine analog linked to cell-penetrating Tat(48-60) peptide favors intracellular delivery and visualization of the antiparasitic drug

et al. 2014

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Therapeutic application of many drugs is often hampered by poor or denied access to intracellular targets. A case in point is miltefosine (MT), an orally active antiparasitic drug, which becomes ineffective when parasites develop dysfunctional uptake systems. We report here the synthesis of a fluorescent BODIPY-embedding MT analogue with appropriate thiol functionalization allowing linkage to the cell-penetrating Tat(48-60) peptide through disulfide or thioether linkages. The resulting constructs are efficiently internalized into the otherwise MT-invulnerable R40 Leishmania strain, resulting in fast parasite killing, hence successful avoidance of the resistance. In the disulfidelinked conjugate, an additional fluoro tag on the Tat moiety allows to monitor its reductive cleavage within the cytoplasm. Terminally differentiated cells such as peritoneal macrophages, impervious to MT unless infected by Leishmania, can uptake the drug in its Tat-conjugated form. The results afford proof-of-principle for using CPP vectors to avert drug resistance in parasites, and/or for tackling leishmaniasis by modulating macrophage uptake.

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Light-Harvesting and Photocurrent Generation by Gold Electrodes Modified with Mixed Self-Assembled Monolayers of Boron−Dipyrrin and Ferrocene−Porphyrin−Fullerene Triad

Cited by 423 publications

References 87 publications

Primary charge-recombination in an artificial photosynthetic reaction center

Primary charge-recombination in an artificial photosynthetic reaction center

Organic semiconductors for device applications: current trends and future prospects

A BODIPY-embedding miltefosine analog linked to cell-penetrating Tat(48-60) peptide favors intracellular delivery and visualization of the antiparasitic drug

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