The Gasochromism of Sputtered WO3 Films

  1. Dr. K. Grassie2,
  2. Prof. Dr. E. Teuckhoff3,
  3. Prof. Dr. G. Wegner4,
  4. Prof. Dr. J. Hausselt5 and
  5. Prof. Dr. H. Hanselka6
  1. A. Georg,
  2. W. Graf and
  3. V. Wittwer

Published Online: 27 APR 2006

DOI: 10.1002/3527607420.ch39

Functional Materials, Volume 13

Functional Materials, Volume 13

How to Cite

Georg, A., Graf, W. and Wittwer, V. (2000) The Gasochromism of Sputtered WO3 Films, in Functional Materials, Volume 13 (eds K. Grassie, E. Teuckhoff, G. Wegner, J. Hausselt and H. Hanselka), Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, FRG. doi: 10.1002/3527607420.ch39

Editor Information

  1. 2

    Philips Forschungslaboratorium, Postfach 500145, 52085 Aachen, Germany

  2. 3

    Siemens AG, Postfach 3240, 91050 Erlangen, Germany

  3. 4

    Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany

  4. 5

    Forschungszentrum Karlsruhe, Postfach 3640, 76201 Karlsruhe, Germany

  5. 6

    Institut für Mechanik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39160 Magdeburg, Germany

Author Information

  1. Fraunhofer Institute for Solar Energy Systems, Oltmannsstr. 5, 79100 Freiburg, Germany

Publication History

  1. Published Online: 27 APR 2006
  2. Published Print: 27 JUN 2000

Book Series:

  1. EUROMAT 99

ISBN Information

Print ISBN: 9783527302543

Online ISBN: 9783527607426

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Keywords:

  • functional materials;
  • sputtered WO3 films;
  • gasochromism

Summary

Sputtered films of WO3 were coated with platinum and colored by exposure to diluted hydrogen gas. Bleaching was achieved with diluted oxygen. Because of its simple layer structure, this so-called gasochromic device is suitable for large-area window applications.

Sputtered WO3 has a columnar structure with pores, which reach to the substrate.

During the coloration, H2 is dissociated on the platinum, transferred into a pore of the WO3 and creates water and an oxygen vacancy. The O vacancy diffuses into the interior of the WO3 and the water slowly leaves the film. The bleaching in argon or vacuum is the reverse reaction. The bleaching by oxygen is the dissociation of the O2 on the platinum, transfer into a pore and recombination with the oxygen vacancy.

Chemisorbed water is essential for the diffusion of the hydrogen along the pore surface. Films with a small amount of water show a slow coloration due to a slow diffusion.

The main aging process in systems using the air for bleaching was detected to be the blocking of the reactive WO3 surface by adsorption of an impurity in the air.