Ab initio study of covalently functionalized carbon nanotubes

In this Letter, the electronic and structural properties of the –COOH, –NH2, and –CONH2 groups, used as sidewall functionalizations by interacting with an (8, 0) single-wall carbon nanotubes, were investigated by using ab initio calculations. The results show that the systems have a very stable interaction with the nanotubes, presenting similar properties. The binding energies and the charge transfers between the functional groups and the tube are calculated and compared. A common feature for the electronic structures of these groups is a half-filled level in the gap region. These covalently functionalized nanotubes are promising systems for attaching biomolecules aiming bio-related applications.