Achieving a fine balance between the strong mechanical and high thermoelectric properties of n-type PbTe–3% Sb materials by alloying with PbS

Both p- and n-type PbTe based materials exhibit excellent thermoelectric properties. However, their mechanical properties are relatively poor compared to those of state-of-the-art thermoelectric materials. In this work, we try to obtain a balance between the strong mechanical properties and high thermoelectric properties of n-type PbTe–3% Sb materials by alloying with PbS. The results indicate that the elastic moduli remain almost unchanged, while the microhardness increases by 62% from a reference value of 54.2 kg mm−2 to approximately 88 kg mm−2 after alloying with PbS (<15%) at room temperature, which is comparable to or even higher than those of common thermoelectric materials. Such a great enhancement of microhardness costs only 7.4% reduction of the dimensionless figure of merit (ZT). A high ZT value of ∼1.5 at 823 K is still maintained. Achieving this fine balance between strong mechanical properties and high thermoelectric properties is crucial to the practical applications of PbTe materials in the electricity generation field.