Fabrication of Cu-Doped Bi2Te3 Nanoplates and Their Thermoelectric Properties

Cu-doped Bi 2 Te 3 hexagonal nanoplates were fabricated by a simple solvothermal method. Scanning electron microscopy and transmission electron microscopy characterization illustrated that the nanoplates are single-crystal ones with an average width of 300 nm and thickness in the range of 20–30 nm. It was demonstrated that Cu x Bi 2 Te 3 nanoplates possess the lowest thermal conductivity (0.8–1.2 W/m K) at 300 K, which is mainly due to the enhanced phonon scattering by grain boundaries. Furthermore, the doped Cu could evidently enhance the power factor of Bi 2 Te 3 through optimizing the carrier transport properties. As a result, Cu 0.02 Bi 2 Te 3 nanoplates exhibit the best thermoelectric performance with a figure of merit of 0.33, which is more than two times higher than that of Bi 2 Te 3 nanoplates.