Interactions of amine functional group with Stone-Wales defects on single-walled carbon nanotubes: A theoretical study

Abstract

Spin-polarized density functional theory has been used to investigate the functionalization of single-walled carbon nanotubes (SWNT) with and without a Stone-Wales (SW) defect by amine (NH2) functional group. The reactivity of SW defects is compared to that of the pristine sidewalls of (5,0), (8,0), and (13,0) SWNT. Our calculations demonstrate that the adsorption of NH2 on SW defect sites is more energetically favorable than that on pristine SWNT sidewalls. All SW defect sites, and particularly the site S1, were considered low-energy adsorption sites for the functionalization process. Furthermore, the binding between the amine group and SW-SWNT is improved for tubes with smaller diameters. The adsorption of NH2 groups on defect sites has a significant influence on the electronic properties of SWNT, changing the electronic states around the Fermi level and converting nonmagnetic semiconductor SWNT to magnetic nanotubes, which is beneficial for the electrical conductivity.