First principles study on the electronic transport properties of C-60 and B-80 molecular bridges

The electronic transport properties of molecular bridges constructed by C-60 and B-80 molecules which have the same symmetry are investigated by first principles calculations combined with a non-equilibrium Green's function technique. It is found that, like C-60, monomer B-80 is a good conductor arising from the charge transfer from the leads to the molecule, while the dimer (B-80)(2) and (C-60)(2) are both insulators due to the potential barrier formed at the molecule-molecule interface. Our further study shows that, although both the homogeneous dimer (B-80)(2) and (C-60)(2) display poor conductivity, the heterogeneous dimer B80C60 shows a very high conductance as a result from the decreased HOMO-LUMO gap and the excess charge redistribution. Finally, we find that the conductivity of both (B-80)(2) and (C-60)(2) can be significantly improved by electron doping, for example, by doping C in (B-80)(2) and doping N in (C-60)(2). (C) 2014 AIP Publishing LLC.