Size-dependent properties of amino-functionalized single walled carbon nanotubes

Using ab initio calculations, we have investigated the sidewall functionalization of several (n, 0) zigzag single wall carbon nanotubes (SWCNTs) by the amine group with n varying from 5 to 23. The results show that the stability of the NH2 group depends on the size of carbon nanotubes. The binding energies and structural properties have been determined and discussed. A transition has been observed when nanotube diameter is near 8 إ. This behavior is confirmed by charge transfer and electronic structure results. As a rule, the amino-functionalization of SWCNTs can be enhanced in the case of tubes with small diameters. The study of carbon nanotubes with different diameters is relevant to the full understanding of their properties.