Largely enhanced thermoelectric performance in p-type Bi2Te3-based materials through entropy engineering

Abstract

Significant advancements have been achieved in the field of thermoelectric technology, with a focus on enhancing and broadening its applications for large-scale waste heat recovery. Studies have sought to obtain room-temperature thermoelectric materials to enhance and expand thermoelectric technology for large-scale waste heat recovery applications. Here we reported on an Ag-doped room temperature Bi₂Te₃-based material (BiSbTe₂Se) with high thermoelectric performance with a figure of merit (zT) of 1.7 at 450 K, and an average zT value of 1.5 from room temperature to 575 K. By employing entropy optimization and incorporating Se atoms into the central layer of BiSbTe₂Se, the thermal conductivity was significantly reduced to a mere 0.4 W m⁻¹ K⁻¹, which was attributed to anharmonicity. The improved carrier concentration through Ag doping largely retained the electrical conductivity value, significantly enhancing the power factor. The newly developed thermoelectric module demonstrated outstanding performance, achieving a maximum conversion efficiency of 8% and an output power of 1.8 W when subjected to a temperature gradient of 225 K.