パイスタック分子接合の多彩な伝導特性

抄録

We demonstrate tuning of charge transport properties through stacks of aromatic molecules on the single molecular scale. The stacks of aromatic molecules are formed in a molecular cage through a self-assemble process, in which non-covalently bound π-stacks act as replaceable modular components with adjustable electronic functions. Scanning tunneling microscopy-based break junction methods revealed that the insertion of the same pairs of aromatic molecules into the cage induces high electronic conductivity (10⁻³–10⁻²G₀, G₀ = 2e²/h), while different donor and acceptor pairs develop additional electronic diode properties. The rectification ratio was estimated to be 1.5–10. Theoretical calculations demonstrate that this rectification behavior originates from the distinct stacking order of the internal aromatic components against the electron-transport direction and the corresponding lowest unoccupied molecular orbital conduction channels localized on one side of the molecular junctions.