Mapping the transition from free-standing vertically-aligned Fe₃C-filled carbon nanotube films to entangled randomly-oriented carbon nanotube buckypapers in presence of a great excess of ferrocene

Self-organized vertically aligned or entangled randomly-oriented carbon nanotubes films filled with ferromagnetic Fe-based phases have recently attracted a great attention for numerous applications as potential electrodes. However the large difference between their synthesis -i) methods, -ii) parameters or -iii) the specific hydrocarbons-requirement have posed many challenges in the growth-selection of one of these film-morphologies. Another important issue is the brittleness of the first type of films which is generally due to low intimate contacts between each carbon nanotube comprised in the vertically aligned films and limits their direct implementation into applications. We propose an advanced low-flow rate chemical vapour deposition approach which allows the selection of either a free-standing flexible film comprising vertically aligned carbon nanotubes filled with large quantities of Fe₃C particles or a free-standing flexible buckypaper comprising entangled randomly-oriented carbon nanotubes films partially filled with Fe₃C through the simple control of the evaporation temperature of the used precursors consisting of large quantities of ferrocene and very low concentrations of dichlorobenzene. The morphological, cross sectional and structural properties of the obtained nanostructures are investigated.