Ab initio study of noncovalent sidewall functionalization of carbon nanotubes

We investigated noncovalent molecular adsorptions onto carbon nanotubes (CNTs), using density-functional theory methods including recently developed hybrid functionals. Planar aromatic molecules have greater binding strength than fully saturated nonaromatic molecules, and adsorption geometries are consistent with the features of intermolecular pi-pi stacking. We show that modifications with alcohol or a thiol terminal group increase the adsorption strength consistently throughout the considered molecules. This result may be used in experiments involving noncovalent sidewall functionalizations of CNTs.