Enhancement of thermoelectric properties in p-type ZnSb alloys through Cu-doping

To meet the growing demand for thermoelectric devices operating in intermediate temperature ranges, it is essential to develop high-performance materials with superior thermoelectric properties and robust mechanical strength. In this study, we systematically optimized carrier concentration by introducing acceptor impurities into ZnSb materials. Our results demonstrate that doping Cu into the Zn site effectively modulates hole carrier concentration, leading to a substantial enhancement in electrical conductivity and a remarkable improvement in power factor (107 %). Consequently, we achieved a high peak ZT of 1.04 at 600 K and an average ZTave value of 0.63 within the temperature range of 300–600 K. This yielded a calculated efficiency of ηmax = 7 % at ΔT = 300 K, for the Zn0.99Cu0.01Sb sample, which is 134 % higher than that of the pristine ZnSb sample (ηmax = 2.98 %). Moreover, the superior hardness and fracture toughness (KIC) of ZnSb samples compared to other state-of-the-art thermoelectric materials make them highly desirable for real-time applications. [Display omitted] •Synthesized a series of Zn1-xCuxSb (x = 0, 0.01, 0.03, and 0.1) samples.•Cu-doping at the Zn site modulates the electronic properties, enhancing the power factor.•Achieved a peak ZT of 1.04 at 600 K and ηmax of 7 % in the optimal Zn0.99Cu0.01Sb.•Obtained improved fracture toughness (KIC) by inhibiting crack propagation.