High Thermoelectric Performance in Rhombohedral GeSe-LiBiTe2

High Thermoelectric Performance in Rhombohedral GeSe-LiBiTe2

Journal of the American Chemical Society

10.1021/jacs.4c04453

http://dx.doi.org/10.1021/jacs.4c04453

Jinfeng Dong, Yukun Liu, Zhi Li, Hongyao Xie, Yilin Jiang, Honghui Wang, Xian Yi Tan, Ady Suwardi, Xiaoyuan Zhou, Jing-Feng Li, Christopher Wolverton, Vinayak P Dravid, Qingyu Yan, Mercouri G. Kanatzidis

13 June 2024

Dong, J., Liu, Y., Li, Z., Xie, H., Jiang, Y., Wang, H., Tan, X. Y., Suwardi, A., Zhou, X., Li, J.-F., Wolverton, C., Dravid, V. P., Yan, Q., & Kanatzidis, M. G. (2024). High Thermoelectric Performance in Rhombohedral GeSe-LiBiTe2. Journal of the American Chemical Society, 146(25), 17355–17364. https://doi.org/10.1021/jacs.4c04453

GeSe, an analogue of SnSe, shows promise in exhibiting exceptional thermoelectric performance in the Pnma phase. The constraints on its dopability, however, pose challenges in attaining optimal carrier concentrations and improving ZT values. This study demonstrates a crystal structure evolution strategy for achieving highly doped samples and promising ZTs in GeSe via LiBiTe2 alloying. A rhombohedral phase (R3m) can be stabilized in the GeSe-LiBiTe2 system, further evolving into a cubic (Fm3̅m) phase with a rising temperature. The band structures of GeSe-LiBiTe2 in the rhombohedral and cubic phases feature a similar multiple-valley energy-converged valence band of L and Σ bands. The observed high carrier concentration (∼1020 cm–3) reflects the effective convergence of these bands, enabling a high density-of-states effective mass and an enhanced power factor. Moreover, a very low lattice thermal conductivity of 0.6–0.5 W m–1 K–1 from 300 to 723 K is achieved in 0.9GeSe-0.1LiBiTe2, approaching the amorphous limit value. This remarkably low lattice thermal conductivity is related to phonon scattering from point defects, planar vacancies, and ferroelectric instability-induced low-energy Einstein oscillators. Finally, a maximum ZT value of 1.1 to 1.3 at 723 K is obtained, with a high average ZT value of over 0.8 (400–723 K) in 0.9GeSe-0.1LiBiTe2 samples. This study establishes a viable route for tailoring crystal structures to significantly improve the performance of GeSe-related compounds.

Publisher Copyright

This research / project is supported by the Ministry of Education - ACRF Tier 1
Grant Reference no. : RG128/21

This research / project is supported by the Ministry of Education - ACRF Tier 1
Grant Reference no. : RT6/22

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see doi.org/10.1021/jacs.4c04453

https://oar.a-star.edu.sg/communities-collections/articles/20373

1520-5126
0002-7863

Institute of Materials Research and Engineering