Effective decoupling of seebeck coefficient and the electrical conductivity through isovalent substitution of erbium in bismuth selenide thermoelectric material

Musah, J.-D., Ilyas, A.M., Novitskii, A., Serhiienko, I., Egbo, K. O., Saianand, G., Khovaylo, V., Kwofie, S., Yu, K. M. and Roy, V. A.L. (2021) Effective decoupling of seebeck coefficient and the electrical conductivity through isovalent substitution of erbium in bismuth selenide thermoelectric material. Journal of Alloys and Compounds, 857, 157599. (doi: 10.1016/j.jallcom.2020.157559)

[img] Text
224232.pdf - Accepted Version
Available under License Creative Commons Attribution Non-commercial No Derivatives.

5MB

Abstract

Recognizing high thermoelectric performance in semiconducting materials is a challenging task. This is because the Seebeck coefficient and electrical conductivity which constitute the thermoelectric power factor are unfavourably coupled. This means decoupling the transport properties of thermoelectric materials to enhance the power factor without compromising the thermal conductivity is essential. Herein we report that the substitution of erbium (Er) within bismuth selenide (Bi2Se3) results in a simultaneous enhancement in Seebeck coefficient and electrical conductivity via effective mass and Fermi energy optimization. The Er-Substitution in Bi2Se3 does not only promote a simultaneous increase in Seebeck coefficient and electrical conductivity but also decreases the thermal conductivity through an enhancement in phonon scattering. Consequently, the optimum composition is found for the Bi1·85Er0·15Se3 sample instigating that, minimal substitution amount is required to optimize the thermoelectric performance. Our numerical calculation also shows that Er substitution alters the Fermi energy of the Bi2Se3 TE materials, thereby enhancing the effective mass. Through Raman and XPS characterization, we also elucidate that Er substitution does not change the chemical structure and chemical bonding of the pristine material appreciably. It thus leads to improvement in the Seebeck coefficient and electrical conductivity via effective mass optimization. This unique work presents a facile, scalable, cost-effective, and controllable synthesis of nanostructured Bi2Se3 toward realizing high-performance thermoelectric devices.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Vellaisamy, Professor Roy
Authors: Musah, J.-D., Ilyas, A.M., Novitskii, A., Serhiienko, I., Egbo, K. O., Saianand, G., Khovaylo, V., Kwofie, S., Yu, K. M., and Roy, V. A.L.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Journal of Alloys and Compounds
Publisher:Elsevier
ISSN:0925-8388
ISSN (Online):1873-4669
Published Online:13 October 2020
Copyright Holders:Copyright © 2020 Crown Copyright
First Published:First published in Journal of Alloys and Compounds 857: 157599
Publisher Policy:Reproduced in accordance with the publisher copyright policy

University Staff: Request a correction | Enlighten Editors: Update this record