J. Phys. Chem. C, 111 (10), 3831 -3835, 2007. 10.1021/jp0669411 S1932-7447(06)06941-X
Web Release Date: February 21, 2007

Copyright © 2007 American Chemical Society

Pump-Probe Spectroscopy of Exciton Dynamics in (6,5) Carbon Nanotubes

Zipeng Zhu, Jared Crochet, Michael S. Arnold, Mark C. Hersam, Hendrik Ulbricht, Daniel Resasco, and Tobias Hertel*

Vanderbilt Institute of Nanoscale Science and Engineering, Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois, Institute for Experimental Physics, University of Vienna, Vienna, Austria, and School of Chemical Engineering and Materials Science, University of Oklahoma, Norman, Oklahoma

Received: October 23, 2006

In Final Form: December 19, 2006

Abstract:

We investigate exciton dynamics in isopycnically enriched (6,5) nanotube-DNA suspensions using femtosecond time-resolved pump-probe spectroscopy. The ground state recovery is characterized by a t-0.45 ± 0.03 power law behavior, indicative of a one-dimensional diffusion-limited reaction that is tentatively attributed to subdiffusive trapping of dark excitons. Spectral transients of bright singlet excitons within the E11 and E22 manifolds exhibit a photobleach (PB) and a photoabsorption (PA) signal of similar strength. The PA is blue-shifted with respect to the PB-signal by 7.5 meV and is attributed to a transition from the dark singlet exciton to a + state within the two exciton E11 manifold.

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