High Thermoelectric Performance of Bi_0.46Sb_1.54Te₃-SnTe: Synergistic Modulation of Electrical and Thermal Transport by the Introduction of Thermoelectric Hetero Nano Region

Abstract

The thermoelectric hetero nano region, as a new strategy, can effectively modulate the electrical and thermal transport properties. In this study, the thermoelectric hetero nano region is explored to improve the thermoelectric performance for Bi_0.46Sb_1.54Te₃ material at room temperature, and a high <i>ZT</i> of 1.45 at 325 K has been achieved. We introduce the thermoelectric hetero nano SnTe regions in a Bi_0.46Sb_1.54Te₃ matrix by mechanical alloying and spark plasma sintering technique, which decouples the relation between electrical and thermal transport properties. The improved electrical conductivity can be attributed to the increase in carrier concentration due to the increased point defects and Bi/Sb_Te antisite defects. Thermoelectric hetero nano regions effectively scatter the acoustic phonon and thus induce the low lattice thermal conductivity of 0.33 W m^-1 K^-1. Due to the synergistic modulation of electrical and thermal transport by the introduction of the thermoelectric hetero nano region, a high <i>ZT</i> value of 1.45 is realized at 325 K.