Diameter selective reaction processes of single-wall carbon nanotubes

A method is presented which allows the study of diameter selective reactions in single-wall carbon nanotubes with an unprecedented accuracy. It is based on the transformation of fullerene peapods into double-wall carbon nanotubes and the study of the resulting diameter distribution of the inner nanotubes with Raman spectroscopy. This yields a spectral resolution increase of about 40 for the modes of different tubes. The method is demonstrated for the diameter selective healing of nanotube defects and yield from C-70 peapod samples. The growth of very small diameter inner tubes from C-70 peapods is demonstrated, which challenges the models of inner nanotube formation. An anomalous absence of middiameter inner tubes is explained by the suppressed amount of C-70 peapods in the transition region between standing and lying C-70 configurations.