High Power Factor Nb-Doped TiO2 Thermoelectric Thick Films: Toward Atomic Scale Defect Engineering of Crystallographic Shear Structures
Autor: | Xiaodong Liu, Demie Kepaptsoglou, Ewa Jakubczyk, Jincheng Yu, Andrew Thomas, Bing Wang, Feridoon Azough, Zhaohe Gao, Xiangli Zhong, Robert Dorey, Quentin M. Ramasse, Robert Freer |
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Jazyk: | angličtina |
Rok vydání: | 2023 |
Předmět: | |
Zdroj: | Liu, X, Kepaptsoglou, D, Jakubczyk, E, Yu, J, Thomas, A, Wang, B, Azough, F, Gao, Z, Zhong, X, Dorey, R, Ramasse, Q M & Freer, R 2023, ' High Power Factor Nb-Doped TiO2 Thermoelectric Thick Films: Toward Atomic Scale Defect Engineering of Crystallographic Shear Structures ', ACS Applied Materials and Interfaces, vol. 15, no. 4, pp. 5071-5085 . https://doi.org/10.1021/acsami.2c16587 Liu, X, Kepaptsoglou, D, Jakubczyk, E, Yu, J, Thomas, A, Wang, B, Azough, F, Gao, Z, Zhong, X, Dorey, R, Ramasse, Q M & Freer, R 2023, ' High Power Factor Nb-Doped TiO 2 Thermoelectric Thick Films : Toward Atomic Scale Defect Engineering of Crystallographic Shear Structures ', ACS Applied Materials and Interfaces . https://doi.org/10.1021/acsami.2c16587 University of Manchester-PURE |
DOI: | 10.1021/acsami.2c16587 |
Popis: | Donor-doped TiO2-based materials are promising thermoelectrics (TEs) due to their low cost and high stability at elevated temperatures. Herein, high-performance Nb-doped TiO2 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 TiO2-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. |
Databáze: | OpenAIRE |
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