Prediction of higher thermoelectric performance in BiOCuSe by weakening electron-polar optical phonon scattering

Zhao, Tianqi, Gibson, Quinn, Daniels, Luke ORCID: 0000-0002-7077-6125, Slater, Ben ORCID: 0000-0001-9738-5848 and Cora, Furio (2020) Prediction of higher thermoelectric performance in BiOCuSe by weakening electron-polar optical phonon scattering.

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Abstract

BiOCuSe is a promising thermoelectric material, but its applications are hindered by low carrier mobility. We use first principles calculations to analyse electron-phonon scattering mechanisms and evaluate their contributions to the thermoelectric figure of merit ZT . The combined scattering of carriers by polar optical (PO) and longitudinal acoustic (LA) phonons yields an intrinsic hole mobility of 32 cm 2 V -1 s -1 at room temperature and a temperature power law of T -1.5 , which agree well with experiments. We demonstrate that electron phonon scattering in the Cu-Se layer dominates at low T , while contributions from the Bi-O layer become increasingly significant at higher T . At room temperature, ZT is calculated to be 0.48 and can be improved by 30% through weakening PO phonon scattering in the Cu-Se layer. This finding agrees with the experimental observation that weakening the carrier-phonon interaction by Te substitution in the Cu-Se layer improves mobility and ZT . At high T , the figure of merit is improved by weakening phonon scattering in the Bi-O layer instead. The theoretical ZT limit of BiOCuSe is calculated to be 2.5 at 875 K.

Item Type:	Article
Divisions:	Faculty of Science and Engineering > School of Physical Sciences
Depositing User:	Symplectic Admin
Date Deposited:	17 Apr 2023 08:41
Last Modified:	15 Mar 2024 05:09
DOI:	10.21203/rs.3.rs-37817/v1
Open Access URL:	https://pubs.rsc.org/en/content/articlelanding/202...
Related URLs:	Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3169595