High Population of Individualized SWCNTs through the Adsorption of Water-Soluble Perylenes

The aqueous dispersion of SWCNTs in the presence of the water-soluble perylene derivatives 1-3 is reported. Significantly, even very low concentrations of the perylenes such as 0.01 wt% of the amphiphilic derivative 3, cause an efficient dissolution of the SWCNTs in water accompanied by a very pronounced individualization. The individualization of SWCNTs in water after ultrasonication in the presence of water-soluble aromatic perylenes was investigated in detail by absorption, emission, and Raman spectroscopy as well as by AFM and cryo-TEM. These studies also revealed that the individualization of the SWCNTs caused by the adsorption of 3 is much more effective than that induced by SDBS, which is the most frequently used surfactant for SWCNT dispersion in water. The pi-pi-stacking interaction and the electronic interaction between the perylene unit and the nanotube surface is reflected, for example, by the distinct absorption and emission features in the UV/vis/nIR, which differ significantly from those observed for SWNTs dispersed in the presence of SDBS and by the quenching of the perylene fluorescence of 3 when being in contact with the tubes.