Ultra-low thermal conductivity in dual doped n-type Bi2Te3 material for enhanced thermoelectric properties

Musah, J.-D., Chen, G., Novitski, A., Serhiienko, I., Ayotunde E., A., Khovaylo, V., Wu, C.-M. L., Zapien, J. A. and Vellaisamy, R. A.L. (2021) Ultra-low thermal conductivity in dual doped n-type Bi2Te3 material for enhanced thermoelectric properties. Advanced Electronic Materials, 7(2), 2000910. (doi: 10.1002/aelm.202000910)

Abstract

Bismuth chalcogenides are promising materials for thermoelectric (TE) application due to their high power factor (product of the square of the Seebeck coefficient and electrical conductivity). However, their high thermal conductivity is an issue of concern. Single doping has proven to be useful in improving TE performance in recent years. Here, it is shown that dual isovalent doping shows the synergistic effect of thermal conductivity reduction and electron density control. The insertion of large atoms in the layered Bi2Te3 structure distorts the crystal lattice and contributes significantly to phonon scattering. The ultralow thermal conductivity (KT = 0.35 W m−1 K−1 at 473 K) compensates for the low power factor and thus enhances TE performance. The density functional theory electronic structure calculation results reveal deep defects states in the valence band, which influences the electronic transport properties of the system. Therefore, the dual dopants (indium and antimony) show a coupled effect of improvement in the density of state near the Fermi level and reduction in the conduction band minimum, thus enhancing electron density. Numerically, it is demonstrated that the dual doping favors acoustic phonon scattering and thus drastically reduces the thermal conductivity.

• Item Type: Articles
• Additional Information: Research Funding: Research Grants Council of Hong Kong Special Administrative Region. Grant Number: T42‐103/16N. Ministry of Science and Higher Education of the Russian Federation. Grant Number: K2‐2020‐045. Research Grants Council, University Grants Committee. Grant Number: T42‐103/16N.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Vellaisamy, Professor Roy
• Authors: Musah, J.-D., Chen, G., Novitski, A., Serhiienko, I., Ayotunde E., A., Khovaylo, V., Wu, C.-M. L., Zapien, J. A., and Vellaisamy, R. A.L.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Advanced Electronic Materials
• Publisher: Wiley
• ISSN: 2199-160X
• ISSN (Online): 2199-160X
• Published Online: 12 January 2021
• Copyright Holders: Copyright © 2021 Wiley‐VCH GmbH
• First Published: First published in Advanced Electronic Materials 7(2): 2000910
• Publisher Policy: Reproduced in accordance with the publisher copyright policy