Entrapping of exohedral metallofullerenes in carbon nanotubes: (CsC60)n@SWNT nano-peapods

Exohedral C60-based metallofullerenes, CsC60, have been synthesized and successfully encapsulated into single-wall carbon nanotubes (SWNTs) in high yield by reducing C60 molecules into anions. High-resolution transmission electron microscopy (HRTEM) images and in situ electron energy loss spectroscopy (EELS) indicate that Cs atoms and C60 molecules align within SWNTs as CsC60 exohedral metallofullerenes, and that the formal charge state of encaged CsC60 is expressed as Cs+1C60-1. The present peapods with the exohedral metallofullerenes provide a new insight and the possibility to fine-tune the electronic and transport properties of carbon nanotubes.