Dye assisted separation of single wall carbon nanotubes

In this work, we demonstrate a simple and reliable method for selectively separating single wall carbon nanotubes (SWNTs). This method is based on a preferable adsorption of linear polynuclear aromatic dyes on metallic SWNTs. With different adsorption amount of soluble dyes, the metallic and semconducting SWNTs show different solubility in solvents, hence can be separated. The types of the obtained SWNTs and the separative efficiency using different dyes have been studied using Raman spectroscopy. It was found that the polynuclear molecules with more benzene rings show higher selectivity. Meanwhile, the separative efficiency is also sensitive to the choice of solvents.