Facile and scalable route for highly efficient enrichment of semiconducting single-walled carbon nanotubes.

Purely semiconducting single-walled carbon nanotubes (s-SWNTs) with a narrow diameter distribution have been produced for HiPco SWNTs. A facile technique combining microwave irradiation with mixed-acid-assisted dispersion has proven efficient for enrichment of s-SWNTs. Using this process, both electronic type-dependent (metallic versus semiconducting) and diameter-dependent separation of SWNTs were simultaneously realized. By mildly controlling experimental conditions, metallic single-walled carbon nanotubes (m-SWNTs) and smaller s-SWNTs were preferentially removed, yielding purely diameter distribution-narrowed semiconducting nanotubes. Furthermore, the chemical structure of carbon nanotubes was restored after thermal annealing, as indicated by Raman and UV absorption investigations. The dual effects of semiconducting enrichment and diameter distribution narrowing, along with facile procedures, make this method promising for large-scale separation of SWNTs and therefore for industrial fabrication of nanotube-based electronics.