Enhancement of the thermoelectric performance of n−type Bi2O2Se by Ce4+ doping

We report on the effect of Ce4+ doping on the thermoelectric properties of Bi2−xCexO2Se (0 ≤ x ≤ 0.15). Bi2−xCexO2Se crystallizes in the tetragonal crystal structure (I4/mmm space group). The doping of Ce4+ for Bi3+ leads to a significant enhancement of electrical conductivity, which is mainly attributed to the increased electron concentration and the decreased band–gap energy. The Ce4+ doping decreases the absolute Seebeck coefficient and increases the thermal conductivity. The highest value of ZT (0.26) is obtained for Bi1.9Ce0.1O2Se at 773 K, which is 37% larger than that of pure Bi2O2Se (0.19) at 773 K. We believe that the Ce4+ doping is highly effective to enhance the thermoelectric properties of Bi2O2Se.