April 22, 2013

Associate Professor Shintaro Ishiwata and Professor Yoshinori Tokura, Department of Applied Physics

Associate Prof. Shintaro Ishiwata and Prof. Yoshinori Tokura's group at the University of Tokyo Graduate School of Engineering and researchers in RIKEN Center for Emergent Matter Science (Director: Yoshinori Tokura) have discovered that a layered material β-CuAgSe is promising for high-efficiency thermoelectrics operating at around room temperature.

Thermoelectric materials can be utilized not only as thermoelectric power generation modules but also as Peltier cooling devices. Although the Peltier cooler has various advantages such as the availability for miniaturization, the cooling power is much lower than the conventional compressor-type cooler. Therefore, exploration of new thermoelectric materials with higher performance has been desired. The research group has found a layered material β-CuAgSe with a partial substitution for Cu shows high thermoelectric performance, which is comparable to the bismuth-based compounds below room temperature down to -200℃. Based on transport measurements and first-principles calculations, the origin of the high thermoelectric performance was ascribed to the extremely high mobility electrons in the silver layers. The present study has provided a guiding principle for exploration of new thermoelectric materials used for high-efficiency Peltier cooling devices.