&lt;title&gt;Ultrafast relaxation of fullerenes and fullerites by broadband femtosecond laser spectrometry&lt;/title&gt;

Boucher, D.; Чекалин, С. В.; Kovalenko, Sergey A.; Matveets, Juru A.; Masselin, P.; Novikov, M. G.; Ragulsky, V. V.; Stepanov, A. G.

doi:10.1117/12.287696

Cited by 5 publications

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“…For C 60 in toluene, a long-lived transient with a peak at 740 nm was observed, which is consistent with the triplet excited-state absorption . In the literature, there have been several ultrafast transient absorption studies done on thin films of C 60 , that reveal spectral properties similar to those measured in Figure , indicating that the colloidal sample is acting much like a solid film. In both cases, the authors describe the transient absorption as coming from formation of a singlet exciton.…”

Section: Resultssupporting

confidence: 79%

“…This contrasts with a 0.96 ns intersystem crossing (ISC) to the triplet excited state and a long-lived triplet state in a solution of C 60 in toluene. Similarities of the transient spectrum and decay rates to studies of thin films of C 60 25,27,86 indicate that at this level of aggregation, the colloidal C 60 particles behave optically much like bulk C 60 . It is estimated that 95.6% of the singlet excited states are quenched.…”

Section: Discussionsupporting

confidence: 58%

“…The data collected for the C 60 [Tol] 15:85 Triton X-100:H 2 O indicate a lifetime of 42.6 ps, which is significantly shorter than that of the C 60 /toluene sample. On the basis of studies done on solid films of C 60 , we believe that this shortened lifetime is due to quenching of the singlet excited state through either a self-quenching process or singlet−singlet annihilation. , Within a micelle, there could be two or more C 60 molecules present, eliminating any slow diffusional processes and leading to very efficient quenching of the C 60 singlet excited state. A long tail absorption was also measured for the C 60 [Tol] 15:85 Triton X-100:H 2 O sample.…”

Section: Resultsmentioning

confidence: 99%

“…17, 86 Within a micelle, there could be two or more C 60 molecules present, eliminating any slow diffusional processes and leading to very efficient quenching of the C 60 singlet excited state. A long tail absorption was also measured for the C 60 [Tol] 15:85 Triton X-100:H 2 O sample.…”

Section: Resultsmentioning

confidence: 99%

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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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Section: Resultssupporting

confidence: 79%

Section: Discussionsupporting

confidence: 58%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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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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“…In 1997, Boucher et al employed the pump-probe technique to investigate ultrafast relaxation of fullerenes and fullerites by broadband femtosecond laser spectrometry. The intensity was varied over the range 10 10 −10 12 W/cm 2 , the energy from 1.57 to 3.14 eV, and the pulse duration from 60 to 350 fs.…”

Section: Experimental Investigation Of Ultrafast Dynamicsmentioning

confidence: 99%

Nonlinear Optical Response and Ultrafast Dynamics in C₆₀

Zhang

George

2009

J. Phys. Chem. A

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Crossed molecular beams experiments were conducted to investigate the chemical dynamics of the reaction of dicarbon molecules, C(2)(X(1)Sigma(g)(+)/a(3)Pi(u)), with diacetylene, C(4)H(2)(X(1)Sigma(g)(+)) at two collision energies of 12.1 and 32.8 kJ mol(-1). The dynamics were found to be indirect, involved C(6)H(2) intermediates, and were dictated by an initial addition of the dicarbon molecule to the carbon-carbon triple bond of diacetylene. The initial collision complexes could isomerize. On the singlet surface, the resulting linear triacetylene molecule (C(6)H(2)(X(1)Sigma(g)(+))) decomposed without an exit barrier to form the linear 1,3,5-hexatriynyl radical (C(6)H(X(2)Pi)). On the triplet surface, the dynamics suggested at least a tight exit transition state involved in the fragmentation of a triplet C(6)H(2) intermediate to yield the 1,3,5-hexatriynyl radical (C(6)H(X(2)Pi)) plus atomic hydrogen. On the basis of the experimental data, we recommend an experimentally determined enthalpy of formation of the 1,3,5-hexatriynyl radical of 1014 +/- 27 kJ mol(-1) at 0 K. Our experimental results and the derived reaction mechanisms gain full support from electronic structure calculations on the singlet and triplet C(6)H(2) potential-energy surfaces. The identification of the 1,3,5-hexatriynyl radical under single collision conditions implies that the neutral-neutral reaction of dicarbon with diacetylene can lead to the formation of 1,3,5-hexatriynyl radicals in the interstellar medium and possibly in the hydrocarbon-rich atmospheres of planets and their moons such as Saturn's satellite Titan.

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Ultrafast Laser Spectroscopy of Nanomaterials

Singh

Dwivedi

2012

Nanomaterials

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<title>Ultrafast relaxation of fullerenes and fullerites by broadband femtosecond laser spectrometry</title>

Cited by 5 publications

References 0 publications

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

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

Nonlinear Optical Response and Ultrafast Dynamics in C₆₀

Ultrafast Laser Spectroscopy of Nanomaterials

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<title>Ultrafast relaxation of fullerenes and fullerites by broadband femtosecond laser spectrometry</title>

Cited by 5 publications

References 0 publications

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

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

Nonlinear Optical Response and Ultrafast Dynamics in C60

Ultrafast Laser Spectroscopy of Nanomaterials

Contact Info

Product

Resources

About

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

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

Nonlinear Optical Response and Ultrafast Dynamics in C₆₀