Effects Of Nb Doping On Thermoelectric Properties Of Zn_4sb_3 At High Temperatures

摘要

The thermoelectric properties of Nb-doped Zn_4Sb_3 compounds, (Zn_(1-x)Nb_x)_4Sb_3 (x = 0, 0.005, and 0.01), were investigated at temperatures ranging from 300 to 685 K. The results showed that by substituting Zn with Nb, the thermal conductivities of all the Nb-doped compounds were lower than that of the pristine β-Zn_4Sb_3. Among the compounds studied, the lightly substituted (Zn_(0.995)Nb_(0.005))_4Sb_3 compound exhibited the best thermoelectric performance due to the improvement in both its electrical resistivity and thermal conductivity. Its figure of merit, ZT, was greater than the undoped Zn_4Sb_3 compound for the temperature range investigated. In particular, the ZT of (Zn_(0.995)Nb_(0.005))_4Sb_3 reached a value of 1.1 at 680 K, which was 69% greater than that of the undoped Zn_4Sb_3 obtained in this study.