Photoexcited fullerene species in Triton-X100 micelles

Crooks, Esther R.; Eastoe, Julian; Beeby, Andrew

doi:10.1039/a704990k

Cited by 17 publications

(9 citation statements)

References 5 publications

(7 reference statements)

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“…Since it is necessary to have well-stabilized charge-transfer products for the harvesting of light energy, researchers often employ a heterogeneous media. For example, intermolecular photoinduced electron-transfer products of fullerene and electron donors live significantly longer in polymeric 6a,b and micellar 21 systems. In the present study, the self-induced aggregation of dyad in the mixed solvent provides a microheterogeneous environment that facilitates charge separation for several hundred microseconds.…”

Section: Resultsmentioning

confidence: 99%

Photoinduced Charge Separation and Stabilization in Clusters of a Fullerene−Aniline Dyad

et al. 1999

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Fullerene-bridge-aniline dyad and the model fulleropyrrolidine compound form stable, optically transparent clusters in mixtures (3:1) of acetonitrile and toluene. Ground-and excited-state properties of the clusters of the dyad and the model compound are compared with their corresponding monomeric forms. Clustering of the dyad as well as the model compound exhibits a red-shifted emission maximum (λ max ∼ 738 nm) compared to their monomeric forms (λ max ∼ 714 nm). The electron transfer from the appended electron donor moiety to the parent fullerene core in the dyad cluster is evident from the decreased (∼80%) fluorescence yield. The formation of fullerene radical anion (absorption maximum at 1010 nm) with a lifetime of several hundreds of microseconds was further confirmed using nanosecond laser (337 nm) flash photolysis experiments. In contrast, the dyad molecules in their monomeric form did not yield any detectable yield of C 60 radical anion following laser pulse excitation. The failure to observe any charge-transfer intermediates following laser pulse excitation, even in polar solvents such as benzonitrile or nitromethane, suggested that fast back-electrontransfer process must be operative in the monomeric dyad system. On the other hand, clustering of the fullerenebased dyads in a mixed-solvent system can provide a unique way to decrease the rate of back electron transfer, thus stabilizing the electron-transfer products.

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Section: Resultsmentioning

confidence: 99%

Photoinduced Charge Separation and Stabilization in Clusters of a Fullerene−Aniline Dyad

et al. 1999

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“…This value is in line with the reported spherical diameter determined by small-angle neutron scattering (SANS) (about 8 nm). 21,22 The slight difference between these two values is due to the fact that DLS measures the HD, whereas SANS measures the size on the basis of contrast scattering length differences between the particle and the solvent. The kinetic study of the T X-100 /liposome interaction was performed using a DLS technique.…”

Section: Resultsmentioning

confidence: 99%

Use of a Dynamic Light Scattering Technique To Study the Kinetics of Liposome Solubilization By Triton X-100

et al. 1999

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“…55,61,[65][66][67][68][69] Some studies have been done of the photophysical properties of these colloidal fullerene suspensions. 67,68,70,71 The photochemical properties, and in particular the generation of reactive oxygen species (ROS) via intersystem crossing to the triplet state, have been of interest both for potential exploitation for photodynamic therapy 9 and regarding concerns about their potential environmental impact, because there have been reports of significant cytotoxicity effects. [50][51][52][53] This work reports on the excited-state dynamics of an aqueous suspension of C 60 suspended in Triton X-100, as shown in Figure 1, to form stable aqueous colloids.…”

Section: Introductionmentioning

confidence: 99%

Photophysical Properties of C₆₀ Colloids Suspended in Water with Triton X-100 Surfactant: Excited-State Properties with Femtosecond Resolution

et al. 2009

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We examine the photophysics of a colloidal suspension of C 60 particles in a micellar solution of Triton X-100 and water, prepared via a new synthesis which allows high-concentration suspensions. The particle sizes are characterized by transmission electron microscopy and dynamic light scattering and found to be somewhat polydisperse in the range of 10-100 nm. The suspension is characterized optically by UV-vis spectroscopy, femtosecond transient absorption spectroscopy, laser flash photolysis, and z-scan. The ground-state absorbance spectrum shows a broad absorbance feature centered near 450 nm which is indicative of colloidal C 60 . The transient absorption dynamics, presented for the first time with femtosecond resolution, are very similar to that of thin films of C 60 and indicate a strong quenching of the singlet excited state on short time scales and evidence of little intersystem crossing to a triplet excited state. Laser flash photolysis reveals that a triplet excited-state absorption spectrum, which is essentially identical in shape to that of molecular C 60 solutions, does indeed arise, but with much lower magnitude and somewhat shorter lifetime. Z-scan analysis confirms that the optical response of this material is dominated by nonlinear scattering. IntroductionSince its discovery, 1 the uniquely symmetrical C 60 molecule has been widely studied, and many applications for it and its derivatives have been proposed, notably lubricants, 2 superconductors, 3 sensors, 4-7 solar cells, 8 and biomedical applications [9][10][11] such as drug delivery and photodynamic therapy. In particular, the photophysical properties of the C 60 molecule have been the subject of intense study. Many authors have reported on the photophysical properties of molecular solutions of C 60 . [12][13][14][15][16][17][18][19][20] Likewise, many authors have studied the photophysical and structural properties of solid films of C 60 . [21][22][23][24][25][26][27][28][29][30][31][32][33][34] Under certain conditions, C 60 forms stable colloidal assemblies in solvents. [35][36][37][38][39][40][41][42][43][44] Colloidal suspensions of C 60 particles can also be formed in binary solvent mixtures, in which one is a good solvent and the other is a poor solvent for C 60 . [45][46][47][48][49] Aqueous suspensions of colloidal C 60 particles are also formed by a number of methods, [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64] including solubilization in micellar solutions. 55,61,[65][66][67][68][69] Some studies have been done of the photophysical properties of these colloidal fullerene suspensions. 67,68,70,71 The photochemical properties, and in particular the generation of reactive oxygen species (ROS) via intersystem crossing to the triplet state, have been of interest both for potential exploitation for photodynamic therapy 9 and regarding concerns about their potential environmental impact, because there have been reports of significant cytotoxicity effects. [50][51][52][53] This work reports on the excited-state dynamics o...

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Photoexcited fullerene species in Triton-X100 micelles

Cited by 17 publications

References 5 publications

Photoinduced Charge Separation and Stabilization in Clusters of a Fullerene−Aniline Dyad

Photoinduced Charge Separation and Stabilization in Clusters of a Fullerene−Aniline Dyad

Use of a Dynamic Light Scattering Technique To Study the Kinetics of Liposome Solubilization By Triton X-100

Photophysical Properties of C₆₀ Colloids Suspended in Water with Triton X-100 Surfactant: Excited-State Properties with Femtosecond Resolution

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Photoexcited fullerene species in Triton-X100 micelles

Cited by 17 publications

References 5 publications

Photoinduced Charge Separation and Stabilization in Clusters of a Fullerene−Aniline Dyad

Photoinduced Charge Separation and Stabilization in Clusters of a Fullerene−Aniline Dyad

Use of a Dynamic Light Scattering Technique To Study the Kinetics of Liposome Solubilization By Triton X-100

Photophysical Properties of C60 Colloids Suspended in Water with Triton X-100 Surfactant: Excited-State Properties with Femtosecond Resolution

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Photophysical Properties of C₆₀ Colloids Suspended in Water with Triton X-100 Surfactant: Excited-State Properties with Femtosecond Resolution