High thermoelectric cooling performance of n-type Mg<sub>3</sub>Bi<sub>2</sub>-based materials.

Mao, Jun; Zhu, Hangtian; Ding, Zhiwei; Liu, Zihang; Gamage, Geethal Amila; Chen, Gang; Ren, Zhifeng · Science · 2019

basic_science · Level V

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Abstract

Thermoelectric materials have a large Peltier effect, making them attractive for solid-state cooling applications. Bismuth telluride (Bi<sub>2</sub>Te<sub>3</sub>)-based alloys have remained the state-of-the-art room-temperature materials for many decades. However, cost partially limited wider use of thermoelectric cooling devices because of the large amounts of expensive tellurium required. We report n-type magnesium bismuthide (Mg<sub>3</sub>Bi<sub>2</sub>)-based materials with a peak figure of merit (<i>ZT</i>) of ~0.9 at 350 kelvin, which is comparable to the commercial bismuth telluride selenide (Bi<sub>2</sub>Te<sub>3-</sub> <i><sub>x</sub></i> Se <i><sub>x</sub></i> ) but much cheaper. A cooling device made of our material and p-type bismuth antimony telluride (Bi<sub>0.5</sub>Sb<sub>1.5</sub>Te<sub>3</sub>) has produced a large temperature difference of ~91 kelvin at the hot-side temperature of 350 kelvin. n-type Mg<sub>3</sub>Bi<sub>2</sub>-based materials are promising for thermoelectric cooling applications.