Electron Transport in Single Molecule Junctions. Direct measurement of electrical and thermoelectric currents using break junction techniques

Understanding transport characteristics of the metal-molecule-metal junctions is a prerequisite for development of functional molecule-based electronic devices. In recent years we successfully implemented the scanning tunnelling break junction (STM-BJ) and mechanically-controllable break junction techniques for the measurement of single molecule conductances, which leads only to a partial description of electron transport. A direct probing of the transport mechanism using complementary methods like inelastic electron tunnelling spectra or thermopower measurements is highly desirable. Additionally, electrochemical STM-BJ gives the possibility to probe different states of electroactive molecules. Therefore, aim of this project is to obtain electrical properties of well-defined redox states of a single molecule and to probe simultaneously the electric and thermoelectric currents, which enables direct probing of the molecular energy level alignment with the electrode's Fermi level. Several types of molecules with different electron transport mechanisms will be tested.