Highly Diameter Selective 13C Enrichment in Carbon Nanotubes

Abstract. We performed vapor phase filling of SWCNTs with various kinds of fullerenes. C60, C70, 13C enriched C60 and mixtures of these were used. The resulting peapods as well as the DWCNTs obtained by annealing were characterized with multi frequency Raman spectroscopy. Simultaneous filling with C60 and C70 was found to take place with the same efficiency. When using the 13C enriched C60 for DWCNT synthesis, mode softening for all inner shell lines was observed, while the outer shell response remained unchanged. The yield of inner shell CNTs is almost the same for C60 and C70 except that C70 is very inefficient in forming mid diameter inner CNTs with RBM frequencies close to 365 cm-1. If inner CNTs are grown from mixed peapods of C70 and 13C enriched C60 these particular CNTs are mainly built from C60. This is confirmed by the observation of distinct line shifts in the inner shell RBM