Synthesis, enhanced stability and structural imaging of C60 and C70 double-wall carbon nanotube peapods

Double-wall carbon nanotubes (DWNTs) encapsulating C60 and C70 fullerenes have been synthesized by the vapor reaction method. Arrangements of C60 and C70 molecules in phases of single chain and multi-layers are observed in DWNTs of different sizes by TEM observation. Distinct signals of XRD patterns and Raman spectra can distinguish C60 and C70 fullerenes inside from those attached outside DWNTs. TGA of the as-prepared DWNT-peapods clearly show that they have a higher thermal stability in comparison with pristine DWNTs. This supplies a simple method to evaluate the filling ratio of peapods, which is 74.7 wt% for the current DWNT-peapods.