Non-covalent separation of metallic and semiconducting single-walled carbon nanotubes

The coexistence of metallic and semiconducting single-walled carbon nanotubes (SWNTs) in commercial available products imposes limitations on their investigation and applications in many fields such as microelectronic devices. Non-covalent separations can preserve the pristine electronic structure and unique properties of both metallic and semiconducting SWNTs, with some of which even realize reversible separations. In this paper, the relationship between the structure and electrical properties of SWNTs is briefly introduced. We also review the characterization methods and the non-covalent separation methods of metallic and semiconducting SWNTs.