Microwave-assisted synthesis of Bi2Se3 ultrathin nanosheets and its electrical conductivities

Abstract

Ultrathin Bi₂Se₃ nanosheets have been successfully fabricated through a microwave-assisted approach in the presence of ethylene glycol (EG) under 1 kW microwave power for 1 minute. The structure and morphology of the obtained products were characterized by powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), selected-area electron diffraction (SAED) and Raman spectroscopy techniques. Based on the control experiments, a possible growth mechanism of Bi₂Se₃ ultrathin nanosheets was proposed. Furthermore, the thermoelectric transport properties of the nanosheets were investigated by measuring the electrical conductivity and the Seebeck coefficient at temperatures ranging from 298 to 523 K. The maximum power factor can reach up to 157 μW m⁻¹ K⁻² at 523 K due to the ultrathin nature of the as-prepared sample, indicating that this promising approach can be extended to the synthesis of other thermoelectrical materials.