Electronic transport through molecules containing pyrimidine units: First-principles calculations

Using density functional theory in combination with Green's functional formalism we study the quantum transport through molecular junctions containing pyrimidine units characterized by a permanent dipole moment. The presence of the pyrimidine rings results in the enhanced current through the junctions for both polarities of the applied voltage. In addition, these systems show clear current rectification due to the polar nature of the molecules. The effect of dihedral angle between phenyl and pyrimidine rings on the current rectification is also studied. The obtained results are explained in terms of charge localization in the system as revealed in the transmission eigenvalues analysis. The obtained results can be useful in understanding the role of polar self-assembled monolayers in interface engineering.