Enhancing the Thermoelectric Performance of Bi2O2Se Ceramics via Multi-Element Doping

Bi2O2Se, as the n-type counterpart of p-type BiCuSeO, has garnered considerable attention. The lower carrier concentration leads to reduced electrical conductivity, prompting extensive research efforts aimed at enhancing its electrical performance. This study prepared Bi2−3x(CeTiSn)xO2Se (x = 0, 0.02, 0.03, and 0.04) ceramics using a combination of high-energy ball milling and cold isostatic pressing techniques. Results demonstrated that the incorporation of multiple elements led to an increase in the carrier concentration within the Bi2O2Se system, thereby improving electrical conductivity. The electrical conductivity increased from 5.1 S/cm for Bi2O2Se to 154.1 S/cm for Bi1.88(CeTiSn)0.04O2Se at 323 K. Furthermore, the maximum power factor value of Bi1.88(CeTiSn)0.04O2Se was 112 μW m−1 K−2 at 763 K. Doping led to a slight increase in thermal conductivity. The figure of merit ZTmax value of Bi1.88(CeTiSn)0.04O2Se was ~0.16, marking a significant enhancement of about 1.45 times compared to that of the pure sample (~0.11).