High-Yield, Single-Step Separation of Metallic and Semiconducting SWCNTs Using Block Copolymers at Low Temperatures

Electronic type separation of SWCNT material is necessary to facilitate the development of carbon nanotube electronics. A convenient, high-yield, single-step separation of metallic and semiconducting SWCNTs has been developed using block copolymers and density gradient ultracentrifugation. In particular by varying the centrifugation temperature and dissolved oxygen content under acidic conditions, extraction efficiencies of up to 6596 were achieved with both metallic and semiconducting SWCNT electronic purity exceeding 9996 as determined by absorption spectroscopy. It was demonstrated that lowering the temperature during the DGU separation, which is expected to increase the difference in densities between metallic and semiconducting nanotube complexes, results in higher purity and yield. Semiconducting and metallic bands are separated simply with a disposable pipet such that specialized fractioning equipment is not required for effective isolation of enriched SWCNTs.