Pseudo-nanostructure and trapped-hole release induce high thermoelectric performance in PbTe

Abstract

Thermoelectric materials can realize direct and mutual conversion between electricity and heat. However, developing a strategy to improve high thermoelectric performance is challenging because of strongly entangled electrical and thermal transport properties. We demonstrate a case in which both pseudo-nanostructures of vacancy clusters and dynamic charge-carrier regulation of trapped-hole release have been achieved in p-type lead telluride-based materials, enabling the simultaneous regulations of phonon and charge carrier transports. We realized a peak <i>zT</i> value up to 2.8 at 850 kelvin and an average <i>zT</i> value of 1.65 at 300 to 850 kelvin. We also achieved an energy conversion efficiency of ~15.5% at a temperature difference of 554 kelvin in a segmented module. Our demonstration shows promise for mid-temperature thermoelectrics across a range of different applications.