Separation and optical identification of semiconducting and metallic single-walled carbon nanotubes

In this work we demonstrate a large-scale separation of arc single-walled carbon nanotubes into semiconducting and metallic fractions by an aqueous two-phase extraction technique. The identification of nanotube conductivity type and the estimation of content for both fractions have been based on UV-vis-NIR optical absorption and time-resolved pump-probe data. The fraction containing up to 98% of semiconducting nanotubes has been obtained. Optimization of the separation technique for the one-step formation of high-purity fractions via either temperature control or regulation of polymer-surfactant concentrations in the mixture has been proposed. The fractions enriched with semiconducting nanotubes can be used for transistor and optoelectronics applications. The metallic fractions can be efficient for formation of electric bus lines. UV-vis-NIR absorbance spectrum of pure semiconducting fraction of arc-SWCNTs with an average diameter of 1.4nm and the photo of 30ml of this suspension.