Modulated electrical transport properties and enhanced thermoelectric performance in tellurium by compositing with copper and doping with antimony

Abstract

As we know, excellent electrical transport performance is essential for outstanding thermoelectric materials. To date, although commonly used doping strategy can optimize the carrier concentration, which also impact the carrier mobility and thus limit the improvement of thermoelectric performance. In this work, we have incorporated the highly conductive secondary phases of Cu into the Te matrix, specifically targeting an improvement in carrier mobility. It is delightful to report that we have successfully elevated the carrier mobility of Te from 186.9 to 372.6 cm²V⁻¹s⁻¹, and the electrical resistivity was significantly reduced. Furthermore, we have also conducted Cu compositing on the basis of carrier concentration optimization by Sb doping. It reveals that the combination of Cu compositing and Sb doping can further decreases the electrical resistivity by collaboratively optimizing the carrier mobility and carrier concentration. Additionally, the presence of Cu as highly conductive secondary phases within the matrix helps to filter the low-energy electrons and enhance the Seebeck coefficient effectively. Ultimately, we achieved a peak zT of ∼0.82 at 607 K for Te_0.994Cu_0.003Sb_0.003. This research provides a new direction for enhancing the performance of Te-based thermoelectric materials.