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

Double-wall carbon nanotubes (DWNTs) encapsulating C-60 and C-70 fullerenes have been synthesized by the vapor reaction method. Arrangements of C-60 and C-70 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 C-60 and C-70 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. (C) 2007 Elsevier B.V. All rights reserved.