Electrical Properties of Nb-, Ga-, and Y-Substituted Nanocrystalline Anatase TiO2 Prepared by Hydrothermal Synthesis

Authors

  • E. Mitchell Hopper,

    Corresponding author
    • Department of Materials Science and Engineering, Northwestern University, Evanston, IL
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  • Frédéric Sauvage,

    1. Laboratory of Photonics and Interfaces, Institute of Chemistry and Chemical Engineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
    2. Laboratoire de Réactivité et Chimie des Solides, Université de Picardie Jules Verne, CNRS UMR6007, Amiens Cedex, France
    3. Department of Chemistry, Northwestern University, Evanston, IL
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  • Aravind Kumar Chandiran,

    1. Laboratory of Photonics and Interfaces, Institute of Chemistry and Chemical Engineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
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  • Michael Grätzel,

    1. Laboratory of Photonics and Interfaces, Institute of Chemistry and Chemical Engineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
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  • Kenneth R. Poeppelmeier,

    1. Department of Chemistry, Northwestern University, Evanston, IL
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  • Thomas O. Mason

    1. Department of Materials Science and Engineering, Northwestern University, Evanston, IL
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Author to whom correspondence should be addressed. e-mail: e-hopper@northwestern.edu

Abstract

Nanocrystalline anatase titanium dioxide powders were produced by a hydrothermal synthesis route in pure form and substituted with trivalent Ga3+ and Y3+ or pentavalent Nb5+ with the intention of creating acceptor or donor states, respectively. The electrical conductivity of each powder was measured using the powder-solution-composite (PSC) method. The conductivity increased with the addition of Nb5+ from 3 × 10−3 S/cm to 10 × 10−3 S/cm in as-prepared powders, and from 0.3 × 10−3 S/cm to 0.9 × 10−3 S/cm in heat-treated powders (520°C, 1 h). In contrast, substitution with Ga3+ and Y3+ had no measureable effect on the material's conductivity. The lack of change with the addition of Ga3+ and Y3+, and relatively small increase upon Nb5+ addition is attributed to ionic compensation owing to the highly oxidizing nature of hydrothermal synthesis.

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