Surface-enhanced Raman scattering studies on chemically transformed carbon nanotube thin films

We review our experimental data obtained by Raman spectroscopy on single-walled carbon nanotubes (SWNTs) using surface-enhanced Raman scattering (SERS). We focused on the study of the dependence of the SERS spectra of SWNTs on both the rough metallic substrate type and the film thickness. In particular, we show that degradation of the nanotubes, mainly metallic, occurs for very thin films with the formation of graphitic, fullerene-like or amorphous carbon particles. We show also that SWNTs reacting with H2SO4 form a salt of the hydrogensulfate type similar to that resulting from graphite-H2SO4 interaction. SWNTs exhibit a complicated spectroelectrochemical behavior in aqueous and non-aqueous H2SO4 solutions that depends also on the sweep potential range. We demonstrate that the oxidation-reduction processes have a quasi-reversible or irreversible character. Finally, SERS studies on compressed SWNTs in different host matrices, inorganic and organic, reveal nanotube breaking and that tube fragments may react or not with the host matrix used. Copyright (c) 2005 John Wiley & Sons, Ltd.