Microwave synthesis combined with SPS sintering to fabricate Pb doped p-type BiCuSeO oxyselenides thermoelectric bulks in a few minutes

An efficient technique to fabricate BiCuSeO oxyselenides thermoelectric bulks is studied. Pb doped p-type BiCuSeO ingots are synthesized by microwave processing for 4 minutes and the bulk materials with 8.7~8.9 gcm⁻³ density are produced after spark plasma sintering for 5 minutes. The XRD and XPS detection results show that all the samples have nearly a single phase indexed to tetragonal BiCuSeO, and the peak positions of Pb 4f_7/2 and 4f_5/2 simple spin-orbit doublet peaks in Bi_0.98Pb_0.02CuSeO and Bi_0.90Pb_0.10CuSeO respectively are 137.93 and 142.76 eV, and 137.49 and 142.49 eV. Holes are the majority carriers with concentrations of 3.22 10²⁰cm⁻³ ~2.40 10²¹cm⁻³ in the doped samples. Bi_0.98Pb_0.02CuSeO shows the highest ZT of 0.76 at 773 K and possible larger values can be achieved at a higher temperature. The fabricate technique described here showing great prospect in the research and manufacturing of thermoelectric bulks.