Enhanced Thermoelectric Performance of p-type AgSbTe<sub>2</sub> via Cu Doping
Wenjie Shu, Yuxia Tang, B. Su, Aijun Hong, Lin Lin, Xiaohui Zhou, Z. B. Yan, Jun‐Ming Liu
Abstract
Recently, the p-type semiconductor AgSbTe 2 has received a great deal of attention due to its promising thermoelectric performance in intermediate temperatures (300–700 K). However, its performance is limited by the suboptimal carrier concentration and the presence of Ag 2 Te impurities. Herein, we synthesized AgSb 1– x Cu x Te 2 ( x = 0, 0.02, 0.04, and 0.06) and investigated the effect of Cu doping on the thermoelectric properties of AgSbTe 2 . Our results indicate that Cu doping suppresses the Ag 2 Te impurities, raises the carrier concentration, and results in an improved power factor (PF). The calculation reveals that Cu doping downshifts the Fermi energy level, reduces the energy band gap and the difference among several valence band maximums, and thereby explains the improvement of PF. In addition, Cu doping reduces the thermal conductivity, possibly attributed to the inhibition of Ag 2 Te impurities and the phonon softening of the AgSb 1– x Cu x Te 2 . Overall, Cu doping improves the ZT of AgSb 1– x Cu x Te 2 . Among all samples, AgSb 0.96 Cu 0.04 Te 2 has a maximum ZT of ∼1.45 at 498 K and an average ZT of ∼1.11 from 298 to 573 K.