Photophysical properties of C60 colloids suspended in water with Triton X-100 surfactant: excited-state properties with femtosecond resolution.
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.
US Army RDECOM-TARDEC, MS-263, 6501 E. 11 Mile Rd., Warren, MI 48397-5000, USA. Andy.Clements@us.army.mil
Andrew F
AF
Clements
Joy E
JE
Haley
Augustine M
AM
Urbas
Alan
A
Kost
R David
RD
Rauh
Jane F
JF
Bertone
Fei
F
Wang
Brian M
BM
Wiers
De
D
Gao
Todd S
TS
Stefanik
Andrew G
AG
Mott
David M
DM
Mackie
D000042:Absorption; D003102:Colloids; D037741:Fullerenes / Q000737:chemistry*; D007834:Lasers; D008027:Light; D046529:Microscopy, Electron, Transmission; D017830:Octoxynol / Q000737:chemistry*; D010316:Particle Size; D010782:Photolysis; D012542:Scattering, Radiation; D053260:Soot / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry*; D013535:Suspensions; D013997:Time Factors; D014867:Water / Q000737:chemistry*
D003102:Colloids; D037741:Fullerenes; D053260:Soot; D013501:Surface-Active Agents; D013535:Suspensions; D014867:Water; D017830:Octoxynol; C069837:fullerene C60