High Thermoelectric Performance in Bismuth Telluride via Constructing MoSe₂‐2D Heterojunction

Abstract Currently, the only thermoelectric (TE) materials commercially available at room temperature are those based on bismuth telluride. However, their widespread application is limited due to their inferior thermoelectric and mechanical properties. In this study, a strategy of growing a rigid second phase of MoSe₂ is employed, in situ within the matrix phase to achieve n‐type bismuth telluride‐based materials with exceptional mechanical and thermoelectric properties. The in situ grown second phase contributes to both the electronic and lattice thermal conductivities. This is primarily attributed to the strong energy filtering effect, as the second phase forms a semi‐common lattice interfacial structure with the matrix phase during growth. Furthermore, for composites containing 2 wt% MoSe₂, a maximum zT value of 1.24 at 373 K can be achieved. On this basis, 8‐pair TE module is fabricated and 1‐pair TE module is optimized using a homemade p‐type material. The optimized 1‐pair TE module generates a maximum output power of 13.6 µW, which is twice that of the 8‐pair TE module and four times more than the 8‐pair TE module fabricated by commercial material. This work facilitates the development of the TE module by presenting a novel approach to obtaining bismuth telluride‐based thermoelectric materials with superior thermoelectric and mechanical properties.