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Research Highlight: Kanatzidis

Cleaning up tin selenide could make cheap thermoelectric material practical

Removal of detrimental oxides allows polycrystalline tin selenide to convert heat to electricity more efficiently than pricier single-crystal material.

The Kanatzidis group in collaboration with Korean researchers (Professor In Chung of Seoul National University) and the Dravid group at Northwestern recently dramatically improved quality of the cheap thermoelectric material tin selenide that could open the path for practical use (C&EN).

Thermoelectric devices could help harness the 65% of global energy produced that is lost as waste heat in places like smokestacks, car engines, and computers.

Six years ago, Kanatzidis and Dravid reported that tin selenide is an excellent thermoelectric material. The catch was only in single crystal form, which is impractical to scale up.

Polycrystalline tin selenide, when pressed as a pellet, is much more robust but it has poor thermoelectric performance dropping by more than 60% compared tosingle crystal SnSe. The reason for the drop, however, is a thin layer of tin oxide that surrounds the small crystal grains in the polycrystalline material. Tin oxide is a good heat conductor, so it allows heat to travel between the grains, which is bad for thermoelectric performance.

Professor Kanatzidis and colleagues found a way to remove this oxide film. After oxide removal, pressing the material into tin selenide pellets samples performed similar to the single crystals.

The research was published in the journal Nature Materials.



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