Hamburg 2001 – wissenschaftliches Programm

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DS: Dünne Schichten

DS 21: Schichteigenschaften IV

DS 21.2: Vortrag

Donnerstag, 29. März 2001, 09:45–10:00, S 13/14

Mechanical properties and the kinetics of switching in gasochromic films — •Tom Pedersen, Christoph Liesch, Hansjörg Weis, Christian Salinga, and Matthias Wuttig — I. Physikalisches Institut, RWTH Aachen, 52056 Aachen, Germany

Switchable coatings are of interest because of their potential applications as smart window coatings, in display technology and as a gas sensor. For a number of gasochromic switchable coatings, simultaneous measurements of reflection, transmission and stress have been carried out in-situ during switching. The measurements of mechanical stresses are important as they yield information on the elastic and/or plastic deformations of the films. They also enable the calculation of the volume change involved in the switching process, as well as supplying additional information important for the understanding of the switching processes. The materials examined include WO_x, GdH_x, and MgH_x. It is found that the mechanical stresses arising in the three films upon H incorporation are of quiet different magnitude, leading to plastic deformations and short lifetimes in some cases and to elastic behaviour and long lifetimes in others. In the case of GdH_x and MgH_x irreversible changes of the films have been found, whilst the processes in the WO_x films have been found to be reversible. The switching kinetics have been simulated by different models resulting in a better understanding of the mechanisms involved.