Opto-electronic effects of electrochemical doping of SWNT
Abstract
Previous studies of the effects of doping in single wall carbon nanotubes (SWNT) have demonstrated a shift in the fermi level upon doping with both electron donors and acceptors, resulting in changes in the optical absorption and resonant Raman spectra. We have doped thin films of SWNT electrochemically in 1M aqueous NaCl at voltages up to +/- 1V vs Ag/AgCl reference electrode, giving us fine control over the dopant concentration in the samples. We observed a slight asymmetry in the change in absorption and resonant Raman scattering intensity of the SWNT with positive (holes) and negative (electrons) doping potentials. The applied electrochemical potential required to compensate for this asymmetry is around 0.4V, and it is consistent across a large variety of sample types. Changes in the resonant Raman spectra upon doping are similar for a wide range of excitation photon energies, which demonstrates the effect of doping not only on the van Hove singularity occupations but also on the broad absorption background that is due to the surface plasmon in SWNT.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MARY17012K