Effects of annealing process on thermoelectric performance for Pb-doped BiCuSeO

In this work, we investigated the effects of annealing process on thermoelectric performance for Pb0.06Bi0.94Cu0.94SeO sample. Under the appropriate annealing time of 573 K, the electrical conductivity was significantly improved on the premises of a higher carrier concentration. As a result, a high power factor of 1096 µWm−1 K−2 was achieved at 323 K. Furthermore, the lattice thermal conductivity obviously decreased as the annealing time rose up to 3 days, which mostly benefited from the stronger phonon scattering and the precipitation of the second phase. Consequently, for the Pb0.06Bi0.94Cu0.94SeO sample annealed for 1 day, a maximum ZT value of 0.85 was obtained at 873 K, which was 57% and 12% higher than those of pristine BiCuSeO and un-annealed sample, respectively. This work proposes an effective post-treatment strategy to enhance the thermoelectric properties of BiCuSeO-based compounds.