Highly improved thermoelectric performance of BiCuTeO achieved by decreasing the oxygen content. (December 2020)

• Record Type: Journal Article
• Authors: Chang, H.-C.; Chen, T.-H.; Sankar, R.; Yang, Y.-J.; Chen, L.-C.; Chen, K.-H.
• Is Part Of: Materials today physics. Volume 15(2020)
• Publication Date: 2020-12
• Subjects: Electrical conductivity -- Hot pressing -- Secondary phases -- Thermal conductivity -- Figure of merit; Materials science -- Periodicals; Physics -- Periodicals; Electronic journals; 530.41
• DOI: 10.1016/j.mtphys.2020.100248
• Languages: English
• ISSNs: 2542-5293

Abstract

Abstract: BiCuTeO is a promising thermoelectric material owing to its intrinsically low thermal conductivity and high carrier concentration. This study investigated the influence of stoichiometric oxygen deficiencies on the thermoelectric performance of BiCuTeO. Bulk BiCuTeO1− x (0.16 ≥ x ) samples were prepared by a conventional solid state reaction and pelleted by hot pressing. Synchrotron X-ray diffraction, electron probe X-ray microanalysis, scanning electron microscopy, and transmission electron microscopy characterized the samples. A maximum value of 1.06 was achieved for the dimensionless figure of merit ZT at 673 K for BiCuTeO0.88, which is approximately 49% better than the current maximal ZT value for BiCuTeO. The power factor was noticeably improved owing to increases in the electrical conductivity and Seebeck coefficient. Moreover, the optimal oxygen deficiency could introduce nanoparticles, resulting in reduced thermal conductivity. The findings will be important for the future development of metal oxide thermoelectric materials for use in practical thermoelectric devices. Graphical abstract: Image 1 Highlights: This study investigated the influence of stoichiometric oxygen deficiency on the thermoelectric performance of BiCuTeO. The bulk BiCuTeO1-x (0.16 ≥ x) samples by a conventional solid state reaction and pelleted these samples by hot pressing. The thermoelectric performance of BiCuTeO was improved by increasing the power factor and reducing the thermal conductivity. The ZT value of BiCuTeO achieved in our study is the highest value reported to date.