Mechanism of molecular conductance enhanced via the D-A effect

Abstract

Donor-acceptor (D-A) molecular architecture is widely employed in the design of organic semiconductors; however, its charge transport characteristics at the single-molecule level remain rarely explored. To elucidate the intrinsic mechanism, this study integrates single-molecule conductance measurements, photophysical spectroscopy, and quantum chemical calculations to research D-A molecule systems. It shows that the D-A effect on conductance enhancement is not governed by a reduced molecular bandgap or a lowered charge injection barrier, but related to the reduction in exciton binding energy for the charge when transported across two electrodes through the molecule