Enhancing thermoelectric performance of Sb₂Te₃ through swapped bilayer defects

Lattice defects are typically used to tailor the thermoelectric properties of materials. It is desirable that such defects improve the electrical conductivity, while, at the same time, reduce the thermal conductivity, for an overall improvement on the thermoelectric properties of materials. Here, we report on an extended defect in Sb₂Te₃ consisting of swapped bilayers with chemical intermixing of Sb and Te atoms, which can be generated and effectively manipulated in polycrystalline samples through synthetic methods and thermal treatments. The swapped bilayers bridge the spatial gaps between the Sb₂Te₃ quintuple-layer blocks, enhancing the charge carrier mobility and thus the electrical conductivity. These defects also result in a reduced lattice thermal conductivity through suppressing phonon transport. These synergistic effects contribute together to an improved thermoelectric quality factor and an enhanced figure of merit (zT) value in Sb₂Te₃.