Relation between zn content and thermoelectric properties of zn4+xsb3 (-0.12⩽x⩽0.12)

A series of seven bulk crystals of Zn_4+xSb₃ (-0.12 ⩽ x ⩽ 0.12) are successfully prepared, and the relation between the Zn content and the thermoelectric properties is investigated. The sample with the nominal composition of Zn_3.96 Sb₃ (x = -0.04) contain the maximum mass fraction of Zn ₄Sb₃. The shapes of the S(T) and ρ(T) curves are drastically changed with varying x in the temperature range from 300 K to 700 K. Whereas the lower x leads to lower ρ, the magnitude of S unchanges, resulting in the fact that the power factor of the Zn-poor compositions in the Zn_4+xSb₃ system is lower than that of the Zn-rich compositions. The details of the influence of the Zn content and the scope of the improvement of the durability are discussed.