Affiliation:
1. Key Laboratory of Radiation Physics and Technology Ministry of Education Institute of Nuclear Science and Technology Sichuan University Chengdu 610064 China
2. Institute of New Energy and Low‐Carbon Technology Sichuan University Chengdu 610065 China
Abstract
AbstractOptimizing carrier concentration in PbTe materials can be achieved effectively through the chemical doping of sodium. Nevertheless, the valence balance can lead to the presence of “deleterious defects” in the PbTe matrix, resulting in low sodium solubility at room temperature. Herein, a strategy for fine‐tuning Pb vacancies to improve sodium solubility is developed. By a trace amount of Se‐doping, the solubility of Na in Pb0.99Te1‐xSex through the preservation of Pb vacancies in the matrix is substantially increased. Additionally, a large number of dense dislocations in the grains, which greatly reduced the lattice thermal conductivity is induced. A high power factor of ≈26 mW cm−1 K−2 and low lattice thermal conductivity of ≈0.43 W m−1 K−1 at 823 K in Pb0.95Na0.04Te0.97Se0.03 is achieved. Ultimately, a high figure of merit, ZT ≈2.2, is obtained at 823 K in quaternary PbTe compound. The current findings not only demonstrate that the introduction of trace amounts of Se and Pb vacancies in the PbTe matrix can effectively enhance Na solubility and minimize thermal conductivity, attaining synergistic improvement in electrical and thermal properties, but also indicate that the synergistic effect of Pb vacancies with a specific dopant is an alternative approach for enhancing ZT.
Funder
National Key Research and Development Program of China