Of catalysts and chirality: Highly-selective growth of structure-specific single-walled carbon nanotubes
(Phys.org) —Carbon – the chemical basis of all known life and an element known as far back as the 8th century BC – exists in a range of forms, or allotropes, with remarkably diverse properties. (Diamond, for example, is transparent and extremely hard tetrahedral lattice that conducts electricity poorly but is an excellent thermal conductor. Graphite, on the other hand – a moderate electrical conductor – is a soft, black, flaky solid formed from sheets of flat hexagonal lattices known as graphene.) Among carbon's allotropes, carbon nanotubes are cylindrical graphene-based nanostructures with properties central to many fields of materials science and technology. In particular, single-walled carbon nanotubes (SWNTs) are carbon nanotubes whose properties change with their chirality – that is, the arrangements of the carbon atoms, which is based on tube diameter and wrapping angle as specified by what is known as their (n,m) value. These variants behave either as...