Precise Regulation of Ultralow Conductance Attenuation in Single-Molecule Hexabenzocoronene Oligomers

Efficient long-range charge transport within molecular wires, which hinges upon ultralow length-dependent conductance attenuation, is essential for molecular electronics and optoelectronics applications. In this study, a series of hexabenzocoronene oligomers are synthesized, and their charge transport behaviors are investigated by using both dynamic and static single-molecule junction techniques. Remarkably, hexabenzocoronene oligomer-based dynamic single-molecule junctions with gold electrodes show an exceptionally low conductance attenuation coefficient of ∼0.046 Å–1, while static single-molecule junctions based on graphene electrodes exhibit a triple value of conductance attenuation. Via the introduction of ionic liquid gates, the molecular conductance is regulated effectively, reducing the attenuation coefficient by more than 50%, due to precise control of the energy offset between the Fermi level of the electrodes and the molecular energy levels. These findings, particularly the efficient control of the molecular conductance attenuation at ultralow levels, indicate a novel approach to achieving long-range transport for practical molecular electronics.