Structure and Conductivity of Epitaxial Thin Films of In-Doped BaZrO3-Based Proton Conductors
Journal article, 2016

Epitaxial thin films of the proton-conducting perovskite BaZr0.53In0.47O3-delta H0.47-2 delta, grown by pulsed laser deposition, were investigated in their hydrated and dehydrated conditions through a multitechniqu approach with the aim to study the structure and proton concentration depth profile and their relationship to proton conductivity. The techniques used were X-ray diffraction, X-ray and neutron reflectivity, nuclear reaction analysis, and Rutherford backscattering, together with impedance spectroscopy. The obtained proton conductivity and activation energy are comparable to literature values for the bulk conductivity of similar materials, thus showing that grain-boundary conductivity is negligible due to the high crystallinity of the film. The results reveal an uneven proton concentration depth profile, with the presence of a 3-4 nm thick, proton-rich layer with altered composition, likely characterized by cationic deficiency. While this surface layer either retains or reobtains protons after desorption and cooling to room temperature, the bulk of the film absorbs and desorbs protons in the expected mariner. It is suggested that the protons in the near-surface, proton rich region are located in proton sites characterized by relatively strong O-H bonds due to weak hydrogen-bond interactions to neighboring oxygen atoms and that the mobility of protons in these sites is generally lower than in proton sites associated with stronger hydrogen bonds. It follows that strongly hydrogen-bonding configurations are important for high proton mobility.

Author

Laura Mazzei

Chalmers, Physics, Condensed Matter Physics

M. Wolff

Uppsala University

D. Pergolesi

Paul Scherrer Institut

J. A. Dura

NIST Center for Neutron Research

Lars Börjesson

Chalmers, Physics, Condensed Matter Physics

P. Gutfreund

Institut Laue-Langevin

M. Bettinelli

Verona University

T. Lippert

Swiss Federal Institute of Technology in Zürich (ETH)

Paul Scherrer Institut

Maths Karlsson

Chalmers, Physics, Condensed Matter Physics

Journal of Physical Chemistry C

1932-7447 (ISSN) 1932-7455 (eISSN)

Vol. 120 50 28415-28422

Subject Categories

Condensed Matter Physics

DOI

10.1021/acs.jpcc.6b08570

More information

Latest update

4/11/2018