Synthesis and thermoelectric properties of Bi2O2Se nanosheets

The pure tetragonal bismuth oxiselenide nanosheets are synthesized by the composite-molten-salt approach at 200 °C. Field emission scanning electron microscopy, X-ray diffraction, and energy dispersive X-ray spectroscopy are used to characterize the structure, morphology, and composition of the sample. The results show that the thickness of the nanosheets is about 120 nm. The sample for thermoelectric property measurements is prepared using cold pressing method. Thermoelectric properties, including electrical conductivity, Seebeck coefficient and thermal conductivity, are measured from room temperature to 470 K. The results show that the sample exhibits n-type semiconductor behavior with low thermal conductivity (κ300 = 0.346 Wm−1 K−1, and κ470 = 0.458 Wm−1 K−1). Although the obtained figure of merit is small, it would be enhanced with increase in temperature.