Enhancing the thermoelectric power factor of nanostructured ZnCo 2 O 4 by Bi substitution

• Published in: RSC advances 2020-05, Vol.10 (32), p.18769-18775
• Main Authors: Alagar Nedunchezhian, A S, Sidharth, D, Rajkumar, R, Yalini Devi, N, Maeda, K, Arivanandhan, M, Fujiwara, K, Anbalagan, G, Jayavel, R
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/D0RA01542C

Bi ZnCo O (0 ≤ ≤ 0.2) nanoparticles with different values have been prepared by the sol-gel method; the structural, morphological, thermal and thermoelectric properties of the prepared nanomaterials are investigated. XRD analysis confirms that Bi is completely dissolved in the ZnCo O lattice till the values of ≤0.1 and the secondary phase of Bi O is formed at higher value ( > 0.1). The synthesized nanomaterials are densified and the thermoelectric properties are studied as a function of temperature. The electrical resistivity of the Bi ZnCo O decreased with value and it fell to 4 × 10 Ω m for the sample with value ≤ 0.1. The Seebeck coefficient value increased with the increase of Bi substitution till the value of 0.1 and decreased for the sample with higher Bi content ( ≤ 0.2) as the resistivity of the sample increased due to secondary phase formation. With the optimum Seebeck coefficient and electrical resistivity, Bi ZnCo O shows the high-power factor ( ) of 2.3 μW K m and figure of merit of 9.5 × 10 at 668 K respectively, compared with other samples. The experimental results reveal that Bi substitution at the Co site is a promising approach to improve the thermoelectric properties of ZnCo O .