Liu, Xiaodong, Kepaptsoglou, Demie orcid.org/0000-0003-0499-0470, Jakubczyk, Ewa et al. (9 more authors) (2023) High Power Factor Nb-Doped TiO2 Thermoelectric Thick Films:Toward Atomic Scale Defect Engineering of Crystallographic Shear Structures. ACS applied materials & interfaces. ISSN 1944-8252
Abstract
Donor-doped TiO 2-based materials are promising thermoelectrics (TEs) due to their low cost and high stability at elevated temperatures. Herein, high-performance Nb-doped TiO 2 thick films are fabricated by facile and scalable screen-printing techniques. Enhanced TE performance has been achieved by forming high-density crystallographic shear (CS) structures. All films exhibit the same matrix rutile structure but contain different nano-sized defect structures. Typically, in films with low Nb content, high concentrations of oxygen-deficient {121} CS planes are formed, while in films with high Nb content, a high density of twin boundaries are found. Through the use of strongly reducing atmospheres, a novel Al-segregated {210} CS structure is formed in films with higher Nb content. By advanced aberration-corrected scanning transmission electron microscopy techniques, we reveal the nature of the {210} CS structure at the nano-scale. These CS structures contain abundant oxygen vacancies and are believed to enable energy-filtering effects, leading to simultaneous enhancement of both the electrical conductivity and Seebeck coefficients. The optimized films exhibit a maximum power factor of 4.3 × 10 -4 W m -1 K -2 at 673 K, the highest value for TiO 2-based TE films at elevated temperatures. Our modulation strategy based on microstructure modification provides a novel route for atomic-level defect engineering which should guide the development of other TE materials.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2023 The Authors. |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Physics (York) |
Depositing User: | Pure (York) |
Date Deposited: | 23 Jan 2023 11:20 |
Last Modified: | 16 Oct 2024 18:59 |
Published Version: | https://doi.org/10.1021/acsami.2c16587 |
Status: | Published online |
Refereed: | Yes |
Identification Number: | 10.1021/acsami.2c16587 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:195572 |