Effect of Sb deficiency on the thermoelectric properties of Zn4Sb3

•Successfully synthesized Sb deficient polycrystalline samples Zn4Sb3−x (x=0.0, 0.1, 0.2) by solid state route.•10% Sb deficiency reduce the lattice thermal conductivity up to 2 times compared to parent compound.•The figure of merit (zT) enhances 37% as compare to parent compound via Sb deficiency in polycrystalline samples.

We have investigated the effect of Sb-deficiency on the thermoelectric figure of merit (zT) of Zn4Sb3 prepared by solid state reaction route. At high temperatures, the Seebeck coefficient (S) and electrical conductivity (σ) increases with increase in Sb deficiency whereas the thermal conductivity (κ) decreases giving rise to an increase in the overall zT value. The observations suggest that creation of vacancies could be an effective route in improving the thermoelectric properties of Zn4Sb3 system.