| Summary: | 碩士 === 國立臺灣大學 === 物理研究所 === 103 === The single-molecule conductance is affected by the electron transport through the electrode–molecule–electrode junctions. One of the most important factors is the energy-level difference between the electrode Fermi level and the frontier
molecular orbitals. This energy difference can be controlled by electrochemical gating, which means pushing the potential of the working electrode toward the redox potential of the molecule. The compounds here are extended metal-atom chains (EMACs), which have well-defined one-electron oxidation reactions, to study the effect of energy-level alignment on the single-molecule conductance. For the scans of electrochemical potential, the single-molecule conductance is measured at a fixed bias and monitored as a function of electrochemical potential. On the other hand, single-molecule i–V curves are obtained at fixed electrochemical potentials. Transition voltages derived from the corresponding Fowler-Nordheim plots are well correlated with the energy barrier heights. Larger conductance and smaller energy barrier heights were found when electrochemical potential was just about the redox potential, indicating the effect of energy-level alignment.
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