Charge Transport Enhancement in Anthracene Molecular Junction: Density Functional Theory Studies

Device miniaturization and a desire to add some functionality for the next-generation electronic circuits have prompted the research community into a single molecule electronics. Here, we analyzed anthracene molecules coupled to Au electrodes through anchor groups. By using density functional theorem (DFT) in combination with non-equilibrium Green’s functional (NEGF) formalism, we investigated the frontier molecular orbitals (MOs) and charge transport nature of the junction by giving special consideration to the anchoring groups (NH2, S, CN and SH), chemical impurity doping (B, N and NB) and side groups (-CH3, -NH2, and -NO2). The results shows that the MOs can vary depending upon the substituents or dopants used. NB-doped has the lowest HOMO-LUMO gap of 0.25eV, and is expected to be more stable. We also observed that charge transport can be p-type or n-type depending on the anchor materials used. It is found that the amines anchor group have a higher conductance (i.e T(E) ≈ 0.98) for an anthracene molecular junctions (MJs). These findings can be very helpful in understanding and fabrication of either n-type or p-typed high conductive single molecule electronic components.