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A and B site doping of a phonon-glass perovskite oxide thermoelectric

Daniels, L.M.; Ling, S.; Savvin, S.N.; Pitcher, M.J.; Dyer, M.S.; Claridge, J.B.; Slater, B.; Corà, F.; Alaria, J.; Rosseinsky, M.J.

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Authors

L.M. Daniels

S.N. Savvin

M.J. Pitcher

M.S. Dyer

J.B. Claridge

B. Slater

F. Corà

J. Alaria

M.J. Rosseinsky



Abstract

By tuning the A site cation size it is possible to control the degree of octahedral distortion and ultimately structural symmetry in the new perovskite solid solution La0.5Na0.5−xKxTiO3, affording a rhombohedral-to-cubic transition as x increases above 0.4. The La3+ and K+ cations are distributed randomly across the A site leading to significant phonon disorder in cubic La0.5K0.5TiO3 (Pm[3 with combining macron]m) which produces a phonon-glass with a thermal conductivity of 2.37(12) W m−1 K−1 at 300 K; a reduction of 75% when compared with isostructural SrTiO3. This simple cation substitution of Sr2+ for La3+ and K+ maintains the flexible structural chemistry of the perovskite structure and two mechanisms of doping for the introduction of electronic charge carriers are explored; A site doping in La1−yKyTiO3 or B site doping in La0.5K0.5Ti1−zNbzO3. The phonon-glass thermal conductivity of La0.5K0.5TiO3 is retained upon doping through both of these mechanisms highlighting how the usually strongly coupled thermal and electronic transport can be minimised by mass disorder in perovskites. Precise control over octahedral distortion in A site doped La1−yKyTiO3, which has rhombohedral (R[3 with combining macron]c) symmetry affords lower band dispersions and increased carrier effective masses over those achieved in B site doped La0.5K0.5Ti1−zNbzO3 which maintains the cubic (Pm[3 with combining macron]m) symmetry of the undoped La0.5K0.5TiO3 parent. The higher Seebeck coefficients of A site doped La1−yKyTiO3 yield larger power factors and lead to increased thermoelectric figures of merit and improved conversion efficiencies compared with the mechanism for B site doping.

Citation

Daniels, L., Ling, S., Savvin, S., Pitcher, M., Dyer, M., Claridge, J., …Rosseinsky, M. (2018). A and B site doping of a phonon-glass perovskite oxide thermoelectric. Journal of Materials Chemistry A, 6(32), 15640-15652. https://doi.org/10.1039/c8ta03739f

Journal Article Type Article
Acceptance Date Jun 20, 2018
Online Publication Date Jul 30, 2018
Publication Date Aug 28, 2018
Deposit Date Aug 6, 2018
Publicly Available Date Aug 6, 2018
Journal Journal of Materials Chemistry A
Print ISSN 2050-7488
Electronic ISSN 2050-7496
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 6
Issue 32
Pages 15640-15652
DOI https://doi.org/10.1039/c8ta03739f
Keywords Renewable Energy, Sustainability and the Environment; General Materials Science; General Chemistry
Public URL https://nottingham-repository.worktribe.com/output/951855
Publisher URL http://pubs.rsc.org/en/Content/ArticleLanding/2018/TA/C8TA03739F#!divAbstract
Contract Date Aug 6, 2018

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