Single Molecule Conductance, Thermopower, and Transition Voltage

• Published in: Nano letters Vol. 13; no. 9; pp. 4326 - 4332
• Main Authors: Guo, Shaoyin, Zhou, Gang, Tao, Nongjian
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 11-09-2013
• Subjects: Alignment; Charge transport; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Conductance; Electric Conductivity; Electric potential; Electrodes; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic structure of nanoscale materials : clusters, nanoparticles, nanotubes, and nanocrystals; Electronic transport in multilayers, nanoscale materials and structures; Energy Transfer; Exact sciences and technology; Fermi surfaces; Molecular energy levels; Nanotechnology; Physics; Thermal properties of condensed matter; Thermal properties of small particles, nanocrystals, nanotubes; Thermodynamics; Voltage; STM break junction; single molecule thermopower; single molecule current−voltage characteristics; Molecular electronics; single molecule conductance; transition voltage spectroscopy; Molecular arrangement; Thermal properties; Electronic structure; Energy levels; Fermi level; Charge transport; IV characteristic
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl4021073

We have measured the thermopower as well as other important charge transport quantities, including conductance, current–voltage characteristics, and transition voltage of single molecules. The thermopower has little correlation with the conductance, but it decreases with the transition voltage, which is consistent with a theory based on Landauer’s formula. Since the transition voltage reflects the molecular energy level alignment, our finding also shows that the thermopower provides valuable information about the relative alignment between the molecular energy levels and the electrodes’ Fermi energy level.