Thermoelectric properties of Zn4Sb3 intermetallic compound doped with Aluminum and Silver

The β-phase Zn4Sb3 has attracted much attention because of its high thermoelectric performance in the intermediate temperature range thanks to disorder in the Zn lattice site. In this work are presented structural, thermal, electric and thermoelectric characterization of Zn4Sb3 pure and Ag, Al doped, prepared by a simple synthesis. Structural and microstructural analyses reveal homogeneous one-phases having compositions in agreement with the nominal ones. After thermoelectric characterization, Ag doping results mostly effective in lowering the resistivity and Seebeck coefficient value, by introducing holes in the system. On the other hand, the Al substitution yields a very small decrease of the Seebeck coefficient but, at the same time, a significant decrease of the thermal conductivity mainly due to the depressed phonon contribution. The thermal conductivity behavior is the main responsible for the good thermoelectric performances of (Zn0.99Al0.01)4Sb3, whose thermoelectric figure of merit reaches the encouraging value of 0.23 at 260 K.