Modulation of charge transport at grain boundaries in SrTiO3: towards high thermoelectric power factor at room temperatureCitation formats

  • External authors:
  • Dursun Ekren
  • Yudong Peng
  • Feridoon Azough

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Modulation of charge transport at grain boundaries in SrTiO3: towards high thermoelectric power factor at room temperature. / Cao, Jianyun; Ekren, Dursun; Peng, Yudong; Azough, Feridoon; Kinloch, Ian; Freer, Robert.

In: ACS Applied Materials and Interfaces , 28.01.2021.

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@article{7cfac11f466042db8c93b9eca7e0c3c5,
title = "Modulation of charge transport at grain boundaries in SrTiO3: towards high thermoelectric power factor at room temperature",
abstract = "Modulation of the grain boundary properties in thermoelectric materials that have thermally-activated electrical conductivity is crucial in order to achieve high performance at low temperatures. In this work, we show directly that the modulation of the potential barrier at the grain boundaries in perovskite SrTiO3 changes the low temperature dependency of the bulk material{\textquoteright}s electrical conductivity. By sintering samples in a reducing environment of increasing strength, we produced La0.08Sr0.9TiO3 (LSTO) ceramics that gradually change their electrical conductivity behaviour from thermally activated to single crystal-like, with only minor variations in Seebeck coefficient. Imaging of the surface potential by Kelvin probe force microscopy found lower potential barriers at the grain boundaries in the LSTO samples that had been processed in the more reducing environments. A theoretical model using band offset at the grain boundary to represent the potential barrier agreed well with the measured grain boundary potential dependency of conductivity. The present work showed an order of magnitude enhancement in electrical conductivity (from 85 to 1287 S cm−1) and power factor (from 143 to 1745 µW m−1 K−2) at 330 K by this modulation of charge transport at grain boundaries. This significant reduction in the impact of grain boundaries on charge transport in SrTiO3 provides an opportunity to achieve the ultimate “phonon glass electron crystal” by appropriate experimental design and processing.",
author = "Jianyun Cao and Dursun Ekren and Yudong Peng and Feridoon Azough and Ian Kinloch and Robert Freer",
year = "2021",
month = jan,
day = "28",
language = "English",
journal = "ACS Applied Materials and Interfaces ",
issn = "1944-8244",
publisher = "American Chemical Society",

}

RIS

TY - JOUR

T1 - Modulation of charge transport at grain boundaries in SrTiO3: towards high thermoelectric power factor at room temperature

AU - Cao, Jianyun

AU - Ekren, Dursun

AU - Peng, Yudong

AU - Azough, Feridoon

AU - Kinloch, Ian

AU - Freer, Robert

PY - 2021/1/28

Y1 - 2021/1/28

N2 - Modulation of the grain boundary properties in thermoelectric materials that have thermally-activated electrical conductivity is crucial in order to achieve high performance at low temperatures. In this work, we show directly that the modulation of the potential barrier at the grain boundaries in perovskite SrTiO3 changes the low temperature dependency of the bulk material’s electrical conductivity. By sintering samples in a reducing environment of increasing strength, we produced La0.08Sr0.9TiO3 (LSTO) ceramics that gradually change their electrical conductivity behaviour from thermally activated to single crystal-like, with only minor variations in Seebeck coefficient. Imaging of the surface potential by Kelvin probe force microscopy found lower potential barriers at the grain boundaries in the LSTO samples that had been processed in the more reducing environments. A theoretical model using band offset at the grain boundary to represent the potential barrier agreed well with the measured grain boundary potential dependency of conductivity. The present work showed an order of magnitude enhancement in electrical conductivity (from 85 to 1287 S cm−1) and power factor (from 143 to 1745 µW m−1 K−2) at 330 K by this modulation of charge transport at grain boundaries. This significant reduction in the impact of grain boundaries on charge transport in SrTiO3 provides an opportunity to achieve the ultimate “phonon glass electron crystal” by appropriate experimental design and processing.

AB - Modulation of the grain boundary properties in thermoelectric materials that have thermally-activated electrical conductivity is crucial in order to achieve high performance at low temperatures. In this work, we show directly that the modulation of the potential barrier at the grain boundaries in perovskite SrTiO3 changes the low temperature dependency of the bulk material’s electrical conductivity. By sintering samples in a reducing environment of increasing strength, we produced La0.08Sr0.9TiO3 (LSTO) ceramics that gradually change their electrical conductivity behaviour from thermally activated to single crystal-like, with only minor variations in Seebeck coefficient. Imaging of the surface potential by Kelvin probe force microscopy found lower potential barriers at the grain boundaries in the LSTO samples that had been processed in the more reducing environments. A theoretical model using band offset at the grain boundary to represent the potential barrier agreed well with the measured grain boundary potential dependency of conductivity. The present work showed an order of magnitude enhancement in electrical conductivity (from 85 to 1287 S cm−1) and power factor (from 143 to 1745 µW m−1 K−2) at 330 K by this modulation of charge transport at grain boundaries. This significant reduction in the impact of grain boundaries on charge transport in SrTiO3 provides an opportunity to achieve the ultimate “phonon glass electron crystal” by appropriate experimental design and processing.

M3 - Article

JO - ACS Applied Materials and Interfaces

JF - ACS Applied Materials and Interfaces

SN - 1944-8244

ER -