Photoinduced Charge Separation and Recombination in a Novel Methanofullerene−Triarylamine Dyad Molecule

Komamine, Satoshi; Fujitsuka, Mamoru; Ito, Osamu; Moriwaki, Kazuyuki; Miyata, Toshiyuki; Ohno, Toshinobu

doi:10.1021/jp002319b

Cited by 104 publications

(108 citation statements)

References 48 publications

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“…S13b †), but gave longer lifetime (950 ps and 2000 ps at 712 nm), presumably because of the lower solvent polarity. 50 Consequently, the transient absorption result, together with the static and time-resolved fluorescence data, are indicative of photoinduced electron transfer and suggest that 1 serves as electron acceptor in the 1-SWCNT donor-acceptor system.…”

Section: Time-resolved Fluorescence and Nanosecond Transient Absorptimentioning

confidence: 85%

Assembly of carbon nanotubes and alkylated fullerenes: nanocarbon hybrid towards photovoltaic applications

et al. 2011

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Taking advantage of the non-covalent interaction between alkyl chains and the sidewalls of a singlewalled carbon nanotube (SWCNT), a nanocarbon hybrid of SWCNT and a fullerene (C 60 ) derivative with long alkyl chains was constructed as a donor-acceptor pair for photovoltaics and nanodevice investigations. It was found that SWCNT could be mostly unbundled by the alkylated C 60 (1) and was well-dispersed in organic solvents. As a photoactive material, the resultant nanocarbon hybrid, 1-SWCNT, performed well in light-energy harvesting applications in photoelectrochemical cells and nanoscale field-effect transistors (FET). Moreover, the 1-SWCNT assembly exhibited superhydrophobicity, providing an interesting opportunity to fabricate nanocarbon-based waterproof optoelectronic devices. In order to understand the photoexcitation process, the 1-SWCNT assembly was electrochemically and spectroscopically characterized. The electrochemical results showed that the SWCNT facilitated electronic communication between 1 and the electrode. The steady-state and timeresolved fluorescence and the photoluminescence excitation studies suggested efficient quenching of the singlet excited state of C 60 . Nanosecond transient absorption data revealed the one-electron reduction of fullerene, C 60 _ À , thereby demonstrating the photoinduced electron transfer from SWCNT to the C 60 unit in the 1-SWCNT assembly.

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Section: Time-resolved Fluorescence and Nanosecond Transient Absorptimentioning

confidence: 85%

Assembly of carbon nanotubes and alkylated fullerenes: nanocarbon hybrid towards photovoltaic applications

et al. 2011

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“…54,55 Since bisbiphenylaniline (N,N-bis(biphenylyl)aniline; BBA) is a very good electron donor with respect to 1 C 60 *, several studies of BBAspacerC 60 molecules have been reported as shown in Figure 32. 56,57 One of the merits of the study of BBAspacerC 60 molecules is the sharp and intense absorption As for short molecular wires, a comparison between the phenylvinyl (PV) linkage (compound 30) and the phenylethynyl (abbreviated as phenylacetyl and PA) linkage (compound 31) is possible for ferrocene (Fc) as electron donor (Figure 33). 59,60 The R CC value for (FcPA) 2 C 60 is larger than that of (FcPV) 2 C 60 ; thus, the observed k S CS values decrease with the length of the bridges.…”

Section: ¹1mentioning

confidence: 99%

Roles of Molecular Wires between Fullerenes and Electron Donors in Photoinduced Electron Transfer

Ito

Yamanaka

2009

Bulletin of the Chemical Society of Japan

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In the photoinduced intramolecular electron transfer events of donorbridgeacceptor molecular systems, the bridges play important roles. In the first part of this account, we review charge separation and charge recombination of porphyrinbridgefullerene systems, in which the porphyrin acts as a photosensitizing electron donor, whereas the ground state of the C 60 moiety acts as an electron acceptor. In such systems, the charge separation usually takes place through the LUMO of the bridges via a super-exchange mechanism and/or a hopping mechanism, depending on their relative LUMO energy levels. On the other hand, the charge recombination of the radical ion pairs usually takes place through the HOMO of the bridges. In the second part, research of charge separation via the excited state of fullerene through the HOMO of the bridges is reviewed. So far, very small damping factors have been reported for ³-conjugated bridges such as oligophenyleneacetylenes, oligothiophenes, and oligothiophenevinylenes. On summarizing these results, it is revealed that switching from the super-exchange mechanism in short bridges to hopping mechanism in longer bridges is important to achieve long distance electron transfer through the bridges.Photoinduced electron transfer (ET) of donoracceptor systems is the most elementary of all photochemical reactions, and plays a crucial role in many essential photoactive devices.14 The functions of conjugated nano-scale donor acceptor molecules are useful for molecular electronic devices 5 and photovoltaic cells. 6,7 Photo-induced electron-transfer systems exhibiting charge-separation (CS) and charge-recombination (CR) processes of the covalently connected donorspacer acceptor systems, in which the spacers are flexible methylene chains, have been extensively studied by the Okada, Mataga, Sakata, and Misumi groups. 811 Recently, fullerene derivatives have been widely applied to construct photovoltaic cells. 12,13 For further advances of these chemically modified fullerenes as molecular electronic devices, it is very important to reveal the general roles of the bridges in the covalently connected donor bridgeacceptor (DBA) systems, in which the donor and acceptor can be photo-excited as illustrated in Figure 1. 14 When the D moiety in a DBA system is photo-excited, the excited state of D (D*) acts as a photosensitizing electron donor, thus CS takes place from D* to the A moiety through the LUMO of B, giving finally the radical ion pair D•+ BA•¹ as illustrated in Figure 2. In this photosensitizing CS process via D*, two cases can be considered depending on the energy level of the LUMO of the B unit relative to the LUMO level of D. One is super-exchange, in which the LUMO energy level of B is higher than the LUMO levels of D and A and another is electron hopping, in which the LUMO level of B is lower than the LUMO level of D. 15,16 Thus, in the superexchange mechanism, the first-step CS (CS-1) after initial photo-excitation (CS-0) is endothermic and the second-step CS (CS-2) is exothermic as shown in F...

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“…[12] This property renders C 60 useful as a building block in artificial-light-harvesting and energy-conversion systems. [13][14][15][16] Non-covalently linked electron-donor-acceptor hybrids that are based on coordinating C 60 to porphyrins or phthalocyanines exhibit a number of advantages, such as their flexible and easy synthesis as well as their ability to monitor through-bond versus throughspace electron-transfer interactions.…”

Section: Introductionmentioning

confidence: 99%

Porphyrin–Phthalocyanine/Pyridylfullerene Supramolecular Assemblies

Pereira

Hausmann

Tomé

et al. 2012

Chemistry A European J

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The synthesis and photophysical properties of several porphyrin (P)-phthalocyanine (Pc) conjugates (P-Pc; 1-3) are described, in which the phthalocyanines are directly linked to the β-pyrrolic position of a meso-tetraphenylporphyrin. Photoinduced energy- and electron-transfer processes were studied through the preparation of H(2)P-ZnPc, ZnP-ZnPc, and PdP-ZnPc conjugates, and their assembly through metal coordination with two different pyridylfulleropyrrolidines (4 and 5). The resulting electron-donor-acceptor hybrids, which were formed by axial coordination of compounds 4 and 5 with the corresponding phthalocyanines, mimicked the fundamental processes of photosynthesis; that is, light harvesting, the transduction of excited-state energy, and unidirectional electron transfer. In particular, photophysical studies confirmed that intramolecular energy-transfer resulted from the S(2) excited state as well as from the S(1) excited state of the porphyrins to the energetically lower-lying phthalocyanines, followed by an intramolecular charge-transfer to yield P-Pc(.+)⋅C(60)(.-). This unique sequence of processes opens the way for solar-energy-conversion processes.

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Photoinduced Charge Separation and Recombination in a Novel Methanofullerene−Triarylamine Dyad Molecule

Cited by 104 publications

References 48 publications

Assembly of carbon nanotubes and alkylated fullerenes: nanocarbon hybrid towards photovoltaic applications

Assembly of carbon nanotubes and alkylated fullerenes: nanocarbon hybrid towards photovoltaic applications

Roles of Molecular Wires between Fullerenes and Electron Donors in Photoinduced Electron Transfer

Porphyrin–Phthalocyanine/Pyridylfullerene Supramolecular Assemblies

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