Microwave Synthesis and Enhanced Thermoelectric Performance of p-Type Bi_0.90Pb_0.10Cu_1-FeSeO Oxyselenides

BiCuSeO oxyselenide, one of the best oxygen-containing thermoelectric materials, is promising with great potential applications. In this work, we present a high ZT of >1.3 in Bi_0.90Pb_0.10Cu_0.96Fe_0.04SeO fabricated via microwave synthesis and subsequent spark plasma sintering (SPS). We added 3-4 atom % Fe to the Pb-doped BiCuSeO to regulate the hole carrier concentration and mobility to 0.8-1.0 × 10²⁰ cm^-3 and ∼40 cm² V^-1 S^-1, respectively, achieving moderate electrical conductivity, high Seebeck coefficient, and low carrier thermal conductivity simultaneously in a dual-doped sample. Under the synergistic enhancement by stress field, dislocation, and nanophase, the lattice thermal conductivity of Bi_0.90Pb_0.10Cu_0.96Fe_0.04SeO is limited to 0.24-0.49 W m^-1 K^-1 at 300-873 K. The development of efficient preparation methods for high-performance thermoelectric materials is significant to promote the application of thermoelectric conversion technology.