Enhanced thermoelectric cooling performance of (Bi, Sb)2Te3 through platinum doping

The requirements for solid-state cooling are growing, especially under extreme conditions. Bi₂Te₃-based alloys stand as the sole thermoelectric (TE) materials currently available for large-scale commercial use, and it is of great significance to further improve their TE properties. In this study, Pt is doped into p-type Bi_0.4Sb_1.6Te₃ to optimize its TE transport performance. The doping of Pt results in a dramatic rise in carrier concentration and power factor. Simultaneously, the existence of the second phases PtSb along with nanopores, contribute to an obvious reduction in lattice thermal conductivity. Hence, the ZT value is boosted to 1.43 at 348 K, and the average ZT from 300 K to 450 K is as high as 1.32. The 7-pair TE cooling module is fabricated based on this material, which exhibits a maximum cooling temperature difference of 92.2 K, and a maximum cooling capacity of 2.9 W when the hot-side temperature is 350 K. This outstanding progress will facilitate the further development of Bi₂Te₃ cooling modules.