Open AccessRegulating Te Vacancies through Dopant Balancing via Excess Ag Enables Rebounding Power Factor and High Thermoelectric Performance in p‐Type PbTe
Author(s) -
Jang Hanhwi,
Park Jong Ho,
Lee Ho Seong,
Ryu Byungki,
Park SuDong,
Ju HyeonAh,
Yang SangHyeok,
Kim YoungMin,
Nam Woo Hyun,
Wang Heng,
Male James,
Snyder Gerald Jeffrey,
Kim Minjoon,
Jung Yeon Sik,
Oh MinWook
Publication year - 2021
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.202100895
Subject(s) - thermoelectric effect , materials science , dopant , thermoelectric materials , doping , seebeck coefficient , power factor , vacancy defect , condensed matter physics , optoelectronics , thermal conductivity , thermodynamics , composite material , power (physics) , physics
Thermoelectric properties are frequently manipulated by introducing point defects into a matrix. However, these properties often change in unfavorable directions owing to the spontaneous formation of vacancies at high temperatures. Although it is crucial to maintain high thermoelectric performance over a broad temperature range, the suppression of vacancies is challenging since their formation is thermodynamically preferred. In this study, using PbTe as a model system, it is demonstrated that a high thermoelectric dimensionless figure of merit, zT ≈ 2.1 at 723 K, can be achieved by suppressing the vacancy formation via dopant balancing. Hole‐killer Te vacancies are suppressed by Ag doping because of the increased electron chemical potential. As a result, the re‐dissolution of Na 2 Te above 623 K can significantly increase the hole concentration and suppress the drop in the power factor. Furthermore, point defect scattering in material systems significantly reduces lattice thermal conductivity. The synergy between defect and carrier engineering offers a pathway for achieving a high thermoelectric performance by alleviating the power factor drop and can be utilized to enhance thermoelectric properties of thermoelectric materials.