Ordered fullerene nanocylinders in large-diameter carbon nanotubes.

A new ordered fullerene phase encapsulated by large-diameter CNTs is systematically investigated by combining a growth technique by chemical vapour deposition, high-resolution transmission electron microscopy and molecular-dynamics simulations. In contrast to fullerenes in smaller (1-2 nm) diameter CNTs, where fullerenes are packed in linear or helical chains, fullerenes form a nanoscale cylinder in double-walled CNTs with diameters of ∼4 nm. The fullerenes were shown to form a nanocylinder with a side wall that resembled the (111) plane of solid C(60). This ordered phase is different from peapods or fullerene solids known so far, and a result of the interaction between the CNT wall and fullerenes. This finding will open up a new field of fullerene science.