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JST Press Release

December 10, 2014
Japan Science and Technology Agency (JST)
5-3, Yonbancho, Chiyoda-ku, Tokyo 102-8666

Realization of crystal silicon with world’s smallest thermal conductivity
-Novel thermoelectric material for reuse of waste heat-

Ecofriendly and low-cost thermoelectric materials with high performance are needed for the use of thermoelectric conversion as safe and clean energy source in human society. A key point to obtain high thermoelectric performance is to achieve low thermal conductivity in materials. We achieved anomalously low thermal conductivity in nanometer-sized structure composed of nanodot crystals of ubiquitous element, Si. This structure exhibited 1/200 times reduction in thermal conductivity compared with macroscopic crystal Si. This result can be evolved to development of ecofriendly and low-cost thermoelectric material. Furthermore, because Si is an electronic device material, this result can bring the possibility to realize the Si electronic devises with function of thermoelectric conversion from a low-temperature waste heat of personal computer or server into electrical energy.

Researcher Information

Research Area “New Materials Science and Element Strategy”
Research Theme “Thermoelectric nano-materials with high conversion efficiency composed of ubiquitous elements”

Journal Information

Yoshiaki Nakamura, Masayuki Isogawa, Tomohiro Ueda, Shuto Yamasaka, Hideki Matsui, Jun Kikkawa, Satoaki Ikeuchi, Takafumi Oyake, Takuma Hori, Junichiro Shiomi, and Akira Sakai. “Anomalous reduction of thermal conductivity in coherent nanocrystal architecture for silicon thermoelectric material” Nano Energy, Available online 10 December 2014, (Corrected proof), doi: 10.1016/j.nanoen.2014.11.029.


[About Researcher]
Yoshiaki Nakamura, Ph.D.
Associate Professor, Graduate School of Engineering Science, Osaka University
URL: http://www.nano.ee.es.osaka-u.ac.jp/staff/nakamura/index.html

[About Program]
Masashi Furukawa
Green Innovation Group, Department of Innovation Research, JST


JST, an integrated organization of science and technology in Japan, establishes an infrastructure for the entire process from the creation of knowledge to the return to the society. For more information, visit http://www.jst.go.jp/EN/