Photochemical properties of C60. Triplet-excited C60 quenching by electron acceptors TCNQ and TCNE in solution. Laser photolysis study

Надточенко, В. А.; Денисов, Н. Н.; Rubtsov, Igor V.; Лобач, А. С.; Moravskii, A. P.

doi:10.1016/0009-2614(93)87168-3

Cited by 30 publications

(45 citation statements)

References 24 publications

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“…Furthermore, TCNE is a strong electron acceptor (E 1/2 (TCNE À /TCNE) ¼ 0.24 V versus saturated calomel electrode (SCE)) [15] compared with C 60 (E 1/2 (C 60 À /C 60 ) ¼ À0.3-0.4 V versus SCE). [12] Figure 3 shows the transient absorption spectra of MDMO-PPV/TCNE blend films with 5 and 50 wt % TCNE.…”

Section: Transient Absorption Spectramentioning

confidence: 99%

Formation of Methanofullerene Cation in Bulk Heterojunction Polymer Solar Cells Studied by Transient Absorption Spectroscopy

Yamamoto

Guo

Ohkita

et al. 2008

Adv Funct Materials

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Photogenerated charge carriers for blend films of poly[2‐methoxy‐5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylenevinylene] (MDMO‐PPV) and [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) have been investigated by transient absorption spectroscopy. The blend film with a low PCBM fraction (<10 wt %) exhibits a wide absorption that ranges from 900 to 1000 nm, which is characteristic of the MDMO‐PPV hole polaron and PCBM radical anion. On the other hand, the blend film with a higher PCBM fraction (> 30 wt %) exhibits a major absorption band at ∼900 nm, which is characteristic of the PCBM radical cation. For identification of charge carriers, the absorption spectrum and molar absorption coefficient of each charged species have been evaluated separately using various combinations of electron donor and acceptor materials. Consequently, the MDMO‐PPV hole polaron has been found to have a broad absorption at ∼950 nm and the PCBM radical anion and cation show a distinct absorption at 1020 and 890 nm, respectively. On the basis of these absorption spectra, the transient spectra observed for the blend films have been simulated. The spectrum for a low PCBM fraction is well reproduced by superposition of the absorption spectra of the MDMO‐PPV hole polaron and PCBM radical anion. On the other hand, the spectrum for a high PCBM fraction is well reproduced by superposition of the absorption spectra of the MDMO‐PPV hole polaron, PCBM radical anion, and PCBM radical cation, which indicates that the PCBM radical cation is formed in the blend films with PCBM at a high concentration. Possible mechanisms for the formation of the PCBM radical cation in the blend are also discussed.

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Section: Transient Absorption Spectramentioning

confidence: 99%

Formation of Methanofullerene Cation in Bulk Heterojunction Polymer Solar Cells Studied by Transient Absorption Spectroscopy

Yamamoto

Guo

Ohkita

et al. 2008

Adv Funct Materials

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“…Since the initial discovery of C 60 or [60]fullerene and the development of a method for its preparation, the fullerenes have been used in the design of electron donor−acceptor (DA) molecular systems. − The fullerenes can function as electron acceptors or even as electron accumulators. As these molecules have a low absorbance at the visible wavelengths, an efficient donor−acceptor dyad containing a fullerene moiety should include a donor capable of picking up light quanta in the visible region. ,, A series of dyads, comprising a fully conjugated porphyrin as a donor and a fullerene as an acceptor, have been synthesized and intensively studied. ,, It has been found that, in addition to the photoinduced charge transfer (CT), the primarily excited porphyrin donor can transfer its excitation energy to the fullerene acceptor.…”

Section: Introductionmentioning

confidence: 99%

Photoinduced Electron Transfer in Phytochlorin−[60]Fullerene Dyads

et al. 1999

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Novel molecular electron donor-acceptor (DA) dyads, composed of a phytochlorin donor and a [60]fullerene acceptor, have been photochemically characterized. In these dyads, a pyrrolidine spacer group links the chlorin and the C 60 moieties covalently, forming a rigid dyad with a short and almost constant D-A distance. The photochemical behavior of the metal-free dyads and the corresponding Zn complexes was studied by means of fluorescence and absorption spectroscopies with femto-and picosecond time resolutions in polar benzonitrile and nonpolar toluene solutions. In consistence with the previous studies on porphyrin-fullerene dyads, the novel chlorin-fullerene dyads underwent a fast intramolecular photoinduced electron transfer in a benzonitrile solution. The recombination rates of the charge-transfer (CT) states were 4.8 × 10 10 s -1 for the Zn dyads and ca. 1.5 × 10 10 s -1 for the metal-free compounds. The CT state was preceded by at least three intermediate states in the time domain from 200 fs to 100 ps. Two of the states were identified as singlet excited states of either the phytochlorin or the fullerene moiety. The third state was attributed to an intramolecular exciplex, which was transformed to the CT state. In the frame of this model, the formation rate constant of the CT state was estimated to be 1.6 × 10 11 s -1 for the Zn dyads and 0.5 × 10 11 s -1 for the metal-free compounds. The formation of the exciplex was also observed in nonpolar solvents, e.g., toluene. In contrast to the behavior in polar solvents, the exciplex relaxed in toluene directly to the ground state, without the formation of the CT state. The lifetime of the exciplex was 140 ps for the Zn dyads and 1-2 ns for the metal-free compounds in toluene.

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“…Excited states of fullerenes can be efficiently quenched by the electron donors with the formation of exciplex, or ion pair, or free ion radicals, indicating that electron-acceptor abilities increase in the singlet and triplet excited states of fullerenes. In addition, the triplet state of C 60 can act as an electron donor with strong electron acceptors such as tetracyanoethylene. − …”

Section: Introductionmentioning

confidence: 99%

Photoinduced Electron Transfer from N,N-Dimethylaniline to Pyrrolidinofullerenes (C₆₀(C₃H₆N)R): Emphasized Substituent Effects with Solvent Polarity Change

et al. 1998

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Photoinduced electron-transfer reactions of pyrrolidinofullerenes {C 60 (C 3 H 6 N)R; R ) H (1), C 6 H 4 NO 2 -p (2), C 6 H 4 CHO-p (3), C 6 H 5 (4), C 6 H 4 OMe-p (5), and C 6 H 4 NMe 2 -p (6)} with N,N-dimethylaniline have been systematically studied by means of nanosecond laser photolysis. From the direct observation of the rises of the anion radicals accompanied by the decays of the triplet states of the fullerenes, the rate constants of electron-transfer reactions (k ET ) via the triplet states were evaluated in polar solvents. Although the k ET values are considerably decreased by the substituents as compared with that of pristine C 60 , the electron is accepted by the C 60 moiety. Among the derivatives, the k ET values of 2 and 3 with electron-withdrawing groups are larger than those of 4 and 1. In less polar solvent, such a substituent effect becomes prominent with decrease in the k ET values, which is in accord with the reactivity-selectivity principle. This behavior can be explained by the Rehm-Weller relation and/or Marcus equation in consideration of the solvent polarity change. Backelectron-transfer rate constants in less polar solvent are larger than those in polar solvent, which is related to the desolvation process and/or loose ion pair formation.

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Photochemical properties of C60. Triplet-excited C60 quenching by electron acceptors TCNQ and TCNE in solution. Laser photolysis study

Cited by 30 publications

References 24 publications

Formation of Methanofullerene Cation in Bulk Heterojunction Polymer Solar Cells Studied by Transient Absorption Spectroscopy

Formation of Methanofullerene Cation in Bulk Heterojunction Polymer Solar Cells Studied by Transient Absorption Spectroscopy

Photoinduced Electron Transfer in Phytochlorin−[60]Fullerene Dyads

Photoinduced Electron Transfer from N,N-Dimethylaniline to Pyrrolidinofullerenes (C₆₀(C₃H₆N)R): Emphasized Substituent Effects with Solvent Polarity Change

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Photochemical properties of C60. Triplet-excited C60 quenching by electron acceptors TCNQ and TCNE in solution. Laser photolysis study

Cited by 30 publications

References 24 publications

Formation of Methanofullerene Cation in Bulk Heterojunction Polymer Solar Cells Studied by Transient Absorption Spectroscopy

Formation of Methanofullerene Cation in Bulk Heterojunction Polymer Solar Cells Studied by Transient Absorption Spectroscopy

Photoinduced Electron Transfer in Phytochlorin−[60]Fullerene Dyads

Photoinduced Electron Transfer from N,N-Dimethylaniline to Pyrrolidinofullerenes (C60(C3H6N)R): Emphasized Substituent Effects with Solvent Polarity Change

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Photoinduced Electron Transfer from N,N-Dimethylaniline to Pyrrolidinofullerenes (C₆₀(C₃H₆N)R): Emphasized Substituent Effects with Solvent Polarity Change