A boost of thermoelectric generation performance for polycrystalline InTe by texture modulation

The new rising binary InTe displays advantageously high electronic conductivity and low thermal conductivity along the [110] direction, providing a high potential of texture modulation for thermoelectric performance improvement. In this work, coarse crystalline InTe material with a high degree of texture along the [110] direction was realized by the oriented crystal hot-deformation method. The coarse grains with high texture not only maintain the preferred orientation of the zone-melting crystal as far as possible, but also greatly depress the grain boundary scattering, thus leading to the highest room temperature power factor of 8.7 μW cm^-1 K^-1 and a high average figure of merit of 0.71 in the range of 300-623 K. Furthermore, the polycrystalline characteristic with refined grains also promotes the mechanical properties. As a result, an 8-couple thermoelectric generator module consisting of p-type InTe and commercial n-type Bi₂Te_2.7Se_0.3 legs was successfully integrated and a high conversion efficiency of ∼5.0% under the temperature difference of 290 K was achieved, which is comparable to traditional Bi₂Te₃ based modules. This work not only demonstrates the potential of InTe as a power generator near room temperature, but also provides one more typical example of a texture modulation strategy beyond the traditional Bi₂Te₃ thermoelectrics.