Realizing synergistic optimization of electrical and thermal transport properties in BiCuSeO ceramics via multi-element doping

Xu, Zhenjiu (author), Wang, Honglei (author), Jiang, Jia-Ling (author), Fu, Zhuang (author), Dong, Songtao (author), Zhang, Binbin (author), Ju, Hongbo (author)

In this study, the design of high-entropy alloys (multi-element substitution, Al▫$^{3+}$▫/La▫$^{3+}$▫/Sb▫$^{3+}$▫/Y▫$^{3+}$▫) was used to increase material entropy and improve heat scattering to further reduce thermal conductivity. Concurrently, Ca▫$^{2+}$▫ ion hole doping was used to improve its electrical conductivity. Therefore, a series of Bi▫$_{0.92- x}$▫Al▫$_{0.02}$▫La▫$_{0.02}$▫Sb▫$_{0.02}$▫Y▫$_{0.02}$▫Ca▫$_x$▫CuSeO (x = 0, 0.02, 0.06, 0.10, and 0.14) ceramics was prepared using a combination of high-energy ball milling and cold isostatic pressing. The multi-element substitution of Al▫$_{0.02}$▫La▫$_{0.02}$▫Sb▫$_{0.02}$▫Y▫$_{0.02}$▫Ca▫$_{0.02}$▫ in the Bi site resulted in a minimum thermal conductivity of 0.35 Wm▫$^{-1}$▫K▫$^{-1}$▫, which is one-third of that of intrinsic BiCuSeO. Simultaneously, the conductivity increased up to 10–20 times that of intrinsic BiCuSeO, proportional to the amount of Ca▫$^{2+}$▫ doping. Furthermore, the optimum component Bi▫$_{0.82}$▫Al▫$_{0.02}$▫La▫$_{0.02}$▫Sb▫$_{0.02}$▫Y▫$_{0.02}$▫Ca▫$_{0.10}$▫CuSeO exhibited an extremely high power factor of 568.55 μWm▫$^{-1}$▫K▫$^{-2}$▫ at 773 K, significantly higher than that of pure BiCuSeO (148.7 μWm▫$^{-1}$▫K▫$^{-2}$▫). Consequently, a peak ZT value of approximately 1.12 was achieved at 773 K, which was 4.48 times higher than that of the pristine BiCuSeO specimen (approximately 0.25). Our findings provide a novel strategy to optimize the thermoelectric properties of BiCuSeO and other materials.

• Language: English
• Keywords: DC magnetron sputtering system, W-Ti-N/Ag composite film, microstructure, mechanical properties
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Author Accepted Manuscript
• Year: 2025
• Number of pages: 8 str.
• Numbering: Vol. 1010, art. 177471
• PID: 20.500.12556/RUL-168378
• UDC: 620.21
• ISSN on article: 1873-4669
• DOI: 10.1016/j.jallcom.2024.177471
• COBISS.SI-ID: 232109827
• Publication date in RUL: 04.07.2025

Record is a part of a journal

• Title: Journal of alloys and compounds
• Publisher: Elsevier
• ISSN: 1873-4669
• COBISS.SI-ID: 23089925

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: DC magnetronski razpršilni sistem, W-Ti-N/Ag kompozitni filmi, mikrostruktura, mehanske lastnosti