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.
The authors gratefully acknowledge the financial support from National R&D Program (2022M3H4A1A04085311) and the Creative Materials Discovery Program (NRF2020M3D1A111049911) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT. This work was also supported by the Korea Institute of Science and Technology (KIST) (2E33181).
