Electric Field Modulation on the Geometric and Electric Structures of Diblock Molecular Diode

摘要

Theoretical investigations on the diblock molecular diode molecule, thiophene-thiazole compound, have been carried out at Hartree-Fock level by considering the interaction from the external electric field. It demonstrates that the electronic structures of this kind of diode molecule are essentially different from those based on the Aviram and Ratner model, in which donor and acceptor-conjugated segments are separated by an insulating σ-bonded segment, in terms of the energy levels of the frontier molecular orbitals as well as their spatial distributions. The introduction of the external EF modifies both the geometric and electronic structures. In particular, the spatial distributions of the frontier molecular orbitals are also shifted under the external EF. Moreover, all these features show strong EF direction dependence due to the build in intrinsic molecular asymmetric features, which could be used to intuitively interpret the asymmetrical current-voltage behaviors of molecules.