Growth of single wall carbon nanotubes from 13C isotope labelled organic solvents inside single wall carbon nanotube hosts

Inner tubes are grown inside SWCNTs from 13C isotope labeled solvents. The low frequency shoulder (indicated by an arrow) of the SWCNT Raman G′ mode of inner tubes (lower frequency component) gradually increases as the 13C isotope content in the encapsulated solvent increases evidencing the enrichment of inner tubes.