RAMAN AND SERS STUDIES OF CARBON NANOTUBES

摘要

We present a survey of Raman and Surface Enhanced Raman Scattering (SERS) studies carried out on carbon nanotubes systems, including single walled nanotubes (SWNTs), multi-walled nanotubes (MWNTs) and nanotubes/polymers composites. We first recall the main features of Raman spectra taken at different excitation wavelengths and we particularly focus on the interactions that take place between tubes when they are in bundles. We predict an upshift of the radial breathing mode (RBM) and we demonstrate this effect experimentally. In the case of tubes deposited on a rough gold or silver layer, i.e. in SERS conditions, we show that interactions take place also with the metallic surface giving rise at some degradation of the tubes. Then, we present results on MWNTs and interpret the low frequency Raman modes, as originating from the RBM of isolated tubes whose interaction between the concentric shells lead again to an up-shift of the frequency of these modes. Finally, we have undertaken a careful study of composites prepared with nanotubes and either saturated or non-saturated polymers. For example, with Poly-(phenylene-vinylene)anotubes composites, it is shown that the luminescence properties of such compounds are strongly affected by the presence of the nanotubes.