Impact of the amount of single-wall carbon nanotubes (SWCNTs) in single-crystalline Bi2Te3 nanoplates/SWCNTs nanocomposite films by drop-casting method

Abstract

To investigate the effect of adding single-wall carbon nanotubes (SWCNTs) to Bi2Te3 nanoplate thin films, we prepared Bi2Te3 nanoplate/SWCNTs nanocomposite thin films with different amounts of SWCNTs using a drop-casting technique. The Bi2Te3 nanoplates prepared by solvothermal synthesis exhibited a single-crystalline phase with rhombohedral crystal structure. The nanoplates had flat surfaces with edge size of approximately 1 μm. The completed nanocomposite thin films were thermally annealed at 250 °C to improve their electrical conductivity. The electrical conductivity of the nanocomposite thin films with added SWCNTs improved, but the power factor decreased compared to those of the Bi2Te3 nanoplate thin film. This occurred because the quality of Bi2Te3 nanoplates in the nanocomposite thin films decreased due to excessive annealing as the introduced SWCNTs have high thermal conductivity. Therefore, we reduced the annealing temperature of nanocomposite thin films to 225 °C and found that the power factor was significantly improved.