Raman doping profiles of polyelectrolyte SWNTs in solution.

We present a resonance Raman study of electrochemical charge transfer doping on polyelectrolyte single-walled carbon nanotubes (SWNTs) in solution. Changes in the intensity of the radial breathing modes of well-identified SWNTs are measured as a function of the electrochemical potential. The intensity is maximum when the nanotubes are neutral.