Evaluation of the Electronic Structure of Single‐Molecule Junctions Based on Current–Voltage and Thermopower Measurements: Application to C 60 Single‐Molecule Junction

The electronic structure of molecular junctions has a significant impact on their transport properties. Despite the decisive role of the electronic structure, a complete characterization of the electronic structure remains a challenge. This is because there is no straightforward way of measuring electron spectroscopy for an individual molecule trapped in a nanoscale gap between two metal electrodes. Herein, a comprehensive approach to obtain a detailed description of the electronic structure in single‐molecule junctions based on the analysis of current–voltage ( I – V ) and thermoelectric characteristics is described. It is shown that the electronic structure of the prototypical C 60 single‐molecule junction can be resolved by analyzing complementary results of the I – V and thermoelectric measurement. This combined approach confirmed that the C 60 single‐molecule junction was highly conductive with molecular electronic conductances of 0.033 and 0.003 G 0 and a molecular Seebeck coefficient of −12 μV K −1 . In addition, we revealed that charge transport was mediated by a LUMO whose energy level was located 0.5≈0.6 eV above the Fermi level of the Au electrode.