Elevating thermoelectric performance in the sub-ambient temperature range for electronic refrigeration
Xiaojing Ma, Chenhao Lin, Hengyu Yang, Yuhao Fu, Kun Liang, Xin Bao, Sheng Ye, Jian Wang, Peng Zhao, Chen Jiang, Shizhen Zhi, Lifu Wu, Sichen Duan, Feng Cao, Qian Zhang, Xiaojing Ma
Abstract
Solid-state thermoelectric coolers, which enable direct heat pumping by utilizing electricity, play an essential role in electronic refrigeration. Given that these devices usually cool down to the sub-ambient temperature range, their performance is critically dependent on the material properties at temperatures below 300 K. Consequently, enhancing the thermoelectric properties of materials at sub-ambient temperature is of paramount importance for advancing cooling technology. Herein, a single-crystalline Mg 3 Bi 2 -based material has been prepared and exhibits high electron mobility. As a result, thermoelectric figure-of-merit values of ∼1.05 at 300 K and ∼0.87 at 250 K (along the ab plane) have been achieved, which are superior to commercial n-type Bi 2 (Te, Se) 3 . Thermoelectric coolers (single- and double-stage devices) based on the n-type single-crystalline Mg 3 Bi 1.497 Sb 0.5 Te 0.003 and p-type (Bi, Sb) 2 Te 3 have been fabricated. The double-stage cooler demonstrates a remarkable maximum cooling temperature difference of ∼106.8 K at the hot-side temperature of 350 K, surpassing the performance of commercial Bi 2 Te 3 -based devices. Notably, the Mg 3 Bi 2 -based double-stage device exhibits exceptional cyclic stability, maintaining its cooling performance without any observable degradation after approximately 2,000 cycles between the input currents of 1 and 3 A. These findings show that single-crystalline Mg 3 Bi 2 alloys hold great promise for thermoelectric cooling applications.