Optimized Thermoelectric Performance of N‐type Bi₂Te_2.7Se_0.3 (BTS) Commercial Materials by Dispersing CuS Nanoparticles

Abstract As a kind of energy crisis‐alleviating material, thermoelectric (TE) materials have attracted the attention of researchers for decades. However, TE materials are still not widely available and one reason is the mismatched performance of n‐type and p‐type materials. In this work, a strategy to boost n‐type Bi₂Te_2.7Se_0.3 crystal by adding CuS nanoparticles through spark plasma sintering (SPS) is reported. The insertion of CuS NPs disperses in the BTS matrix brings the interfaces between CuS and BTS, which can effectively enhance the Seebeck coefficient and decrease the thermal conductivity by decreasing the carrier concentration and promoting the phonon scattering. As a result, the highest ZT value of 0.89 at 393 K is realized with 0.8 wt% CuS NPs doping, which is 1.37 times that of pure BTS crystal. Our work of adding CuS NPs into pure BTS to form interfaces offers a convenient approach for improving n‐type thermal materials with both optimized electrical properties and thermal properties.