Ultrasonication-induced extraction of inner shells from double-wall carbon nanotubes characterized via in situ spectroscopy after density gradient ultracentrifugation

Even though ultrasonication is considered to be an effective method disperse carbon nanotubes (CNTs), its devastating effects on the are often neglected. Here, even mild found rapidly extract inner single-wall CNTs (SWCNTs) from outer shells of double-wall (DWCNTs). As-synthesized DWCNTs gently solubilized in a surfactant solution, strictly avoiding any ultrasonication, followed by two consecutive density gradient ultracentrifugation (DGU) steps obtain purified colloidal solution isolated DWCNTs. The latter carefully selected based situ resonant Raman (RRS) and fluorescence (PL) spectroscopy, measured as function depth directly ultracentrifuge tube after DGU. These ultrasonicated successive time while intermittently probing sample via RRS PL spectroscopy. results unravel very fast increasing yet saturating extraction mechanism that leads formation fluorescing SWCNTs. A statistical high-resolution transmission electron microscopy study confirms drastic increase SWCNTs evidences forms both This demonstrates how easily extracts individually DWCNTs, unavoidably complicating further spectroscopic studies severely.