Effect of Ta Doping on the Microstructure and Thermoelectric Properties of Bi[sub.2]O[sub.2]Se

• Published in: Metals (Basel ) Vol. 12; no. 11
• Main Authors: Jiang, Jia-Ling, Dong, Song-Tao, Fu, Zhuang, Yu, Miao-Cheng, Zhao, Lijun, Wang, Lei
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.11.2022
• Subjects: Thermal properties; Thermoelectricity
• ISSN: 2075-4701; 2075-4701
• DOI: 10.3390/met12111881

In this study, Bi[sub.2−x]Ta[sub.x]O[sub.2]Se (x = 0, 0.02, 0.04, 0.06, and 0.08) ceramics were prepared using a synthesis method combining high-energy ball milling and cold pressing. Furthermore, the effects of tantalum (Ta) doping on the microstructure and thermoelectric properties of Bi[sub.2]O[sub.2]Se were systematically investigated. The results indicate that Ta doping effectively improves the carrier concentration and mobility, thus increasing the electrical conductivity from 8.75 S cm[sup.−1] to 39.03 S cm[sup.−1] at 323 K. Consequently, the power factor is improved, reaching a maximum value of 124 μW m[sup.−1] K[sup.−2] for the Bi[sub.1.92]Ta[sub.0.08]O[sub.2]Se sample at 773 K. Moreover, the thermal conductivity of Bi[sub.1.96]Ta[sub.0.04]O[sub.2]Se is reduced to 0.50 Wm[sup.−1] K[sup.−1]. Finally, the maximum dimensionless figure of merit (ZT) value of the Bi[sub.1.94]Ta[sub.0.06]O[sub.2]Se sample reached 0.18, which was 64% higher than that of Bi[sub.2]O[sub.2]Se (0.11). These results indicate that Ta doping and high-energy ball milling can optimize the electrical and thermal properties and thus improve the thermoelectric properties of ceramics.