Density functional calculations of structural and electronic properties of a BN-doped carbon nanotube

The attachment of a variety of nitrogen nucleophilic groups to BN-doped single wall carbon nanotubes (SWCNTs) was characterized by quantum mechanical calculations at the DFT-level. We found that the binding energies for all systems lie between −6.90 and −30.13 kcal/mol and are in the order guanidine > arginine > ammonia > imidazole > chitosan > pyridine > m-nitroaniline, which is analogous to the pKa. m-Nitroaniline and pyridine grafted tubes display a smaller energy gap, 0.252 and 0.347 eV, respectively, compared to an isolated BN-doped SWCNT, 0.430 eV. For the other cases, the energy gaps did not change significantly, which is in keeping with the results for the densities of states (DOS). In the cases of m-nitroaniline and pyridine, electron density is seen at the Fermi level of both SWCNTs and probe molecules when the DOS is split into these two contributions, different from the isolated probe molecules. Thus, m-nitroaniline and pyridine attached to BN-doped SWCNTs increase the conductivity of the system.