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Impedance Analysis of Dielectric Nanoparticles Enabled via a Self-Assembled Monolayer

Authors

  • Sasidhar Siddabattuni,

    1. Chemistry Department, Missouri University of Science and Technology (formerly the University of Missouri-Rolla), Rolla, Missouri
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  • Thomas P. Schuman,

    Corresponding author
    • Chemistry Department, Missouri University of Science and Technology (formerly the University of Missouri-Rolla), Rolla, Missouri
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  • Vladimir Petrovsky,

    1. Materials Science and Engineering Department, Missouri University of Science and Technology, Rolla, Missouri
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  • Fatih Dogan

    1. Materials Science and Engineering Department, Missouri University of Science and Technology, Rolla, Missouri
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    • Member, The American Ceramic Society

Author to whom correspondence should be addressed. e-mail: tschuman@mst.edu

Abstract

Impedance spectroscopy has been shown to be a powerful tool to investigate the dielectric characteristics of powders suspended in suitable liquids. The electrical and dielectrical contributions of different components of the slurry can be extracted from the impedance spectra through measurement of frequency-dependent relaxations. However, for ferroelectric powders that possess innate surface conductivity, such as BaTiO3, nanoparticles have sufficient conductivity to exclude low-frequency fields that preclude impedance characterization of the particle core. In this work, the slurry technique is shown to be effective for dielectric characterization of not only micrometer-sized particles through equivalent circuit modeling but also applicable to nanometer size dielectric particles upon remediating the conductive surface defect. Application of a self-assembled monolayer (SAM) onto the nanoparticle as a surface passivation layer reduces the surface conductivity, stabilizes the nanoparticles to dissolution, and allows a reproducible measurement and modeling of the nanoparticle dielectric characteristics including nanoparticle permittivity. The dielectric permittivity of surface passivated, ~40 nm diameter barium titanate particles was measured to be εr ~ 135.

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