Chemical Composition Modulation Realizing Remarkable Improvement of Thermoelectric Performance in CuInTe2-Based Alloy

Luping Qu; Yong Luo; Cong Li; Zhengliang Du; Xie Li; Jiaolin Cui

doi:10.1021/acsami.4c02739

Chemical Composition Modulation Realizing Remarkable Improvement of Thermoelectric Performance in CuInTe₂-Based Alloy

ACS Appl Mater Interfaces. 2024 Apr 23. doi: 10.1021/acsami.4c02739. Online ahead of print.

Authors

Luping Qu^{1

2}, Yong Luo², Cong Li³, Zhengliang Du¹, Xie Li¹, Jiaolin Cui¹

Affiliations

¹ School of Materials and Chemical Engineering, Ningbo University of Technology, Ningbo 315016, China.
² School of Materials Science and Physics, School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, China.
³ Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China.

PMID: 38651864
DOI: 10.1021/acsami.4c02739

Abstract

CuInTe₂ (CIT) is one of the typical ternary chalcogenides known for its characteristic mixed polyanionic/polycationic site defects, making it a subject of continuous interest in the field of thermoelectrics. In this work, we propose a chemical composition modulation strategy for CIT by alloying GeTe and then introducing a copper deficiency (denoted by V_Cu). This strategy aims to unpin its Fermi level (F_r) and shift F_r into the valence band (VB) while simultaneously enabling coupling between the optical and acoustic phonon, thereby providing an extra phonon scattering path at low frequencies. The simultaneous composition regulations not only enhance the carrier concentration (n_H) to 10¹⁹-10²⁰ cm^-3 but also significantly reduce the lattice thermal conductivity (κ_L) to ∼0.48 W m^-1 K^-1, thus effectively realizing electro-acoustic coordination in the present material. As a consequence, the thermoelectric (TE) performance is remarkably improved with the highest TE figure of merit (ZT) of 1.51 at ∼838 K. This value ranks at a higher level among CIT-based materials, which showcases the great significance of chemical composition modulation.

Keywords: CuInTe2; carrier and phonon transport; chemical composition modulation; copper deficiency (VCu); lattice thermal conductivity (κL); thermoelectrics.