A single molecule junction in which one molecule is wired between electrodes is chemically extremely precise.This nanostructure is a new thermoelectric material that is expected to achieve high thermoelectric conversion (conversion of thermal energy and electrical energy) performance by using the thermal and electrical transport characteristics peculiar to a single molecule system that reflects the quantum effect.

　Since the first single-molecule thermoelectric measurement was reported in 2007, thermoelectric measurements have been carried out for various single-molecule junctions.However, although the importance of the electrode / molecular interface in the thermoelectric performance of a single molecule junction has been theoretically shown, it is difficult to investigate experimentally and has not been verified so far.

　This time, the research group of Associate Professor Tsutsui and his colleagues applied a nano-machining break junction element (a thin metal wire with a hollow structure made on a flexible substrate using microfabrication technology. A single-molecule structure between electrodes can be made). We realized stable single-molecule device formation at room temperature and evaluated its thermoelectric performance.As a result, it was clarified that the thermoelectric conversion performance of a single molecule element can be improved by 1 times or more compared to the average value by devising the atomic level structure of the electrode-molecular contact (distance between the electrode and molecule, etc.). bottom.

　This makes it possible to design electrode / molecular contact structures that contribute to high-performance single-molecule thermoelectric devices, and is expected to be applied to thermoelectric device applications for single-molecule devices.

Paper information: [Scientific Reports] Roles of vacuum tunneling and contact mechanics in single-molecule thermopower