Switching properties of bi-OPE-monothiol molecular junctions: Substituent effects and improvement of open-close ratio

The electronic transport properties of a new kind of molecular switches -bi-OPE-monothiol molecular switches -were studied by applying first-principles calculations and generalized elastic scattering Green's function. The numerical results show that, for a bi-OPE-molecule junction, the offset face-to-face configuration induces more delocalized molecular orbitals, and results in higher conductivity than the parallel face-to-face configuration, so it can be used as a molecular switch. The side substituent groups containing more delocalized electrons can strengthen the intermolecular coupling and raise the conductivities of bi-OPE-monothiol molecular devices. On the basis of the investigations, we find a scheme to enhance the open-close ratios of bimolecular switches.