Enhancing Thermoelectric Performance in P‐Type Sb2Te3‐Based Compounds Through Nb─Ag Co‐Doping with Donor‐Like Effect

Abstract

AbstractP‐type Sb2Te3 has been recognized as a potential thermoelectric material for applications in low‐medium temperature ranges. However, its inherent high carrier concentration and lattice thermal conductivity led to a relatively low ZT value, particularly around room temperature. This study addresses these limitations by leveraging high‐energy ball milling and rapid hot‐pressing techniques to substantially enhance the Seebeck coefficient and power factor of Sb2Te3, yielding a remarkable ZT value of 0.55 at 323 K due to the donor‐like effect. Furthermore, the incorporation of Nb─Ag co‐doping increases hole concentration, effectively suppressing intrinsic excitations ≈548 K while maintaining the favorable power factor. Simultaneously, the lattice thermal conductivity can be significantly reduced upon doping. As a result, the ZT values of Sb2Te3‐based materials attain an impressive range of 0.5–0.6 at 323 K, representing an almost 100% improvement compared to previous research endeavors. Finally, the ZT value of Sb1.97Nb0.03Ag0.005Te3 escalates to 0.92 at 548 K with a record average ZT value (ZTavg) of 0.75 within the temperature range of 323–573 K. These achievements hold promising implications for advancing the viability of V–VI commercialized materials for low‐medium temperature application.