The hollow structure of SWCNTs can also be used to synthesize linear carbon chains and graphene nanoribbons, which can then be characterized spectroscopically by wavelength-dependent Raman spectroscopy. Also the outer wall of the SWCNTs can be used to create new heterostructures. Peculiar examples of such heterostructures are double-wall carbon nanotubes, for which we revealed an efficient inner-to-outer-wall energy transfer.
