Rational electronic and structural designs advance BiCuSeO thermoelectrics

Gu, Yan and Shi, Xiao-Lei ORCID: https://orcid.org/0000-0003-0905-2547 and Pan, Lin and Liu, Wei-Di and Sun, Qiang and Tang, Xiao and Kou, Liang-Zhi and Liu, Qing-Feng and Wang, Yi-Feng and Chen, Zhi-Gang ORCID: https://orcid.org/0000-0002-9309-7993 (2021) Rational electronic and structural designs advance BiCuSeO thermoelectrics. Advanced Functional Materials:2101289. ISSN 1616-301X


Abstract

In this work, a record high thermoelectric figure‐of‐merit ZT of 1.6 ± 0.2 at 873 K in p‐type polycrystalline Bi0.94Pb0.06CuSe1.01O0.99 by a synergy of rational band manipulation and novel nanostructural design is reported. First‐principles density functional theory calculation results indicate that the density of state at the Fermi level that crosses the valence band can be significantly reduced and the measured optical bandgap can be enlarged from 0.70 to 0.74 eV by simply replacing 1% O with 1% Se, both indicating a potentially reduced carrier concentration and in turn, an improved carrier mobility and a boosted power factor up to 9.0 µW cm−1 K−2. Meanwhile, comprehensive characterizations reveal that under Se‐rich condition, Cu2Se secondary microphases and significant lattice distortions triggered by Pb‐doping and Se‐substitution can be simultaneously achieved, contributing to a reduced lattice thermal conductivity of 0.4 W m−1 K−1. Furthermore, a unique shear exfoliation technique enables an effective grain refinement with higher anisotropy of the polycrystalline pellet, leading to a further improved power factor up to 10.9 µW cm−1 K−2 and a further reduced lattice thermal conductivity of 0.30 W m−1 K−1, which gives rise to record high ZT.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published online: 10 April 2021. Permanent restricted access to Published version, in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Future Materials (1 Jan 2017 -)
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Future Materials (1 Jan 2017 -)
Date Deposited: 20 Apr 2021 02:58
Last Modified: 22 Sep 2021 05:37
Fields of Research (2008): 09 Engineering > 0912 Materials Engineering > 091205 Functional Materials
Fields of Research (2020): 40 ENGINEERING > 4016 Materials engineering > 401605 Functional materials
Identification Number or DOI: https://doi.org/10.1002/adfm.202101289
URI: http://eprints.usq.edu.au/id/eprint/41799

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