Modulating Charge Separation and Charge Recombination Dynamics in Porphyrin−Fullerene Linked Dyads and Triads:  Marcus-Normal versus Inverted Region

Imahori, Hiroshi; Tamaki, Koichi; Guldi, Dirk M.; Luo, Chuping; Fujitsuka, Mamoru; Ito, Osamu; Sakata, Yoshiteru; Fukuzumi, Shunichi

doi:10.1021/ja003346i

Cited by 546 publications

(425 citation statements)

References 128 publications

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“…2) in a linked triad, ZnP-H 2 P-C 60 (8,9), in which the zinc tetraphenylporphyrin (ZnP), free-base tetraphenylporphyrin (H 2 P), and fullerene (C 60 ) moieties (N-methyl-2-phenyl-3,4-fulleropyrrolidine) are rigidly linked by amide spacers (Fig. 1A).…”

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confidence: 99%

“…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).…”

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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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confidence: 99%

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confidence: 99%

Primary charge-recombination in an artificial photosynthetic reaction center

Kobori

Yamauchi

Akiyama

et al. 2005

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

Self Cite

101

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“…Porphyrinogen formation is known to be often reversible. Hence, along with the independent formation of A 3 B-porphyrin and other porphyrins, the obtained B 4 -porphyrinogen reacts with aldehyde 8 b or 8 d leading to the whole set of A x B 4Àx porphyrins, but these reactions proceed at lower rates than the formation of B 4 . On the contrary, the Lewis basicities of 8 a and 8 c are close to that of 7 and therefore in these cases aldehydes of both types, A and B, are activated to similar extents.…”

Section: Synthesismentioning

confidence: 99%

Synthesis of New Porphyrin–Fullerene Dyads Capable of Forming Charge‐Separated States on a Microsecond Lifetime Scale

Konev

Khlebnikov

Prolubnikov

et al. 2014

Chemistry A European J

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A series of covalently linked axially symmetric porphyrin-fullerene dyads with a rigid pyrrolo [3,4-c]pyrrolic linker enabling a fixed and orthogonal arrangement of the chromophores has been synthesized and studied by means of transient absorption spectroscopy and cyclic voltammetry. The lifetime of the charge-separated state has been found to depend on the substituents on the porphyrin core, reaching up to 4 ms for a species with meso-(p-MeOC 6 H 4 ) substituents. The ground and excited electronic states of model compounds have been calculated at the DFT and TD-DFT B3LYP(6-31G(d)) levels of theory and analyzed with regard to the effect of the substituent on the stabilization of the charge-separated state in the porphyrin-fullerene ensemble with a view to explaining the observed dependence.

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“…Fullerene and its functionalized derivatives were soon preferred to quinones, because it was observed that they can considerably accelerate charge separation, while at the same time slowing down charge recombination [56,57].…”

Section: Supramolecular Assembliesmentioning

confidence: 99%

Quantum modeling of ultrafast photoinduced charge separation

Rozzi

Troiani

Tavernelli

2017

J. Phys.: Condens. Matter

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Phenomena involving electron transfer are ubiquitous in nature, photosynthesis and enzymes or protein activity being prominent examples. Their deep understanding thus represents a mandatory scientific goal. Moreover, controlling the separation of photogenerated charges is a crucial prerequisite in many applicative contexts, including quantum electronics, photo-electrochemical water splitting, photocatalytic dye degradation, and energy conversion. In particular, photoinduced charge separation is the pivotal step driving the storage of sun light into electrical or chemical energy. If properly mastered, these processes may also allow us to achieve a better command of information storage at the nanoscale, as required for the development of molecular electronics, optical switching, or quantum technologies, amongst others.In this Topical review we survey recent progress in the understanding of ultrafast charge separation from photoexcited states. We report the state-of-the-art of the observation and theoretical description of charge separation phenomena in the ultrafast regime mainly focusing on molecularand nano-sized solar energy conversion systems. In particular, we examine different proposed mechanisms driving ultrafast charge dynamics, with particular regard to the role of quantum coherence and electron-nuclear coupling, and link experimental observations to theoretical approaches based either on model Hamiltonians or on first principles simulations.

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Modulating Charge Separation and Charge Recombination Dynamics in Porphyrin−Fullerene Linked Dyads and Triads: Marcus-Normal versus Inverted Region

Cited by 546 publications

References 128 publications

Primary charge-recombination in an artificial photosynthetic reaction center

Primary charge-recombination in an artificial photosynthetic reaction center

Synthesis of New Porphyrin–Fullerene Dyads Capable of Forming Charge‐Separated States on a Microsecond Lifetime Scale

Quantum modeling of ultrafast photoinduced charge separation

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