Electronic Structures of Self-Assembled Monolayer of Molecules of Symmetric Disulfides of Benzoic Acid

摘要

The electronic properties of the self-assembled monolayer (SAM) of molecules of symmetric disulfides of benzoic acid with functional elements of H, F and Br have been studied by the first-principles calculation method. This study found that the electronic structure and the dipole moment of this SAM depend strongly on the electronegativity and size of the functional element. The variations of charge transfer among constituent ions and the dipole moment are approximately linear with respect to the external electric field even though there is a gap between the highest-occupied-molecular-orbital (HOMO) and the lowest-unoccupied-molecular-orbital (LUMO) bands. This finding suggests that the conductance of SAM may not vanish when the bias is smaller than the energy gap.