Synthesis of Fe-Doped Tetrahedrites Cu12-xFexSb4S13 and Characterization of Their Thermoelectric Properties

• Published in: Korean Journal of Metals and Materials Vol. 58; no. 5; pp. 340 - 347
• Main Authors: Kim, Sung-Yoon, Pi, Ji-Hee, Lee, Go-Eun, Kim, Il-Ho
• Format: Journal Article
• Language: English
• Published: 대한금속·재료학회 01.05.2020
• Subjects: 재료공학
• ISSN: 1738-8228; 2288-8241
• DOI: 10.3365/KJMM.2020.58.5.340

Tetrahedrite (C12Sb4S13) has attracted attention as a p-type thermoeletric material with very low thermal conductivity induced by the anharmonic oscillation of Cu due to the lone-pair electrons of Sb. Many studies have been conducted to improve its thermoelectric performance by partially substituting the transition elements for the Cu sites. In this study, Fe-doped tetrahedrites Cu12-xFexSb4S13 (x = 0.1-0.4) were prepared by mechanical alloying and hot pressing. The tetrahedrite phase was successfully synthesized by mechanical alloying without post-annealing and exhibited stability even without phase transition after hot pressing. Moreover, the Fe content was observed to be directly proportional to the lattice constant, which confirmed the Fe substitutions on the Cu sites. The electrical conductivity was observed to decrease with the increase in the Seebeck coefficient due to the charge compensation caused by Fe doping (electron donation). The highest power factor was 0.84 mWm-1K-2 at 723 K for the specimen with x = 0.1; however, it decreased with an increase in Fe content. In addition, as the Fe content increased, the electronic thermal conductivity decreased. Thus, the lowest thermal conductivity value was obtained for the specimen with x = 0.4 (0.45–0.64 Wm-1K-1) in the temperature range of 323–723 K. As a result, the maximum value of the dimensionless figure of merit (ZT = 0.80) was achieved at 723 K for the specimen with x = 0.2.