RESUMO
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 Bi0.46Sb1.54Te3 material at room temperature, and a high ZT of 1.45 at 325 K has been achieved. We introduce the thermoelectric hetero nano SnTe regions in a Bi0.46Sb1.54Te3 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/SbTe 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 ZT value of 1.45 is realized at 325 K.
RESUMO
α-MgAgSb shows promise as a potential new low-temperature thermoelectric (TE) material and has been widely researched recently. We explored the effects of sintering conditions on the properties of MgAgSb-based thermoelectric materials through manipulating a spark plasma sintering system (SPS), where Ag vacancies and Mg point defects play a dominant role. The transport properties of MgAgSb were optimized effectively and efficiently, especially for electrical transport. As a result, we obtained a steady power factor (PF) of â¼17 µW cm-1 K-2, owing to the optimal carrier concentration of 9.8 × 1019 cm-3. Additionally, α-MgAgSb exhibits an ultralow lattice thermal conductivity of around 0.45 Wm-1 K-1 at 375 K. More importantly, a high ZT value of 0.85 was achieved below 375 K, approaching room temperature.
