Abstract
We investigated the gasochromic coloration of amorphous tungsten oxide films having oxygen compositions between WO0.25 and WO3.0. The films were deposited by the reactive radio frequency (r. f.) magnetron sputtering with varying oxygen partial pressure. The oxygen and hydrogen concentration of the tungsten oxide films were determined using the Rutherford Backscattering Spectrometry (RBS) and the Elastic Recoil Detection Analysis (ERDA), respectively. The optical transmittance was examined for the films coated with palladium catalysis during the exposure of diluted hydrogen gas. Superior gasochromic properties were obtained for the films consisting of tungsten trioxide, WO3. For the films with lower oxygen concentration than WO3, the optical transmittance hardly changed during the hydrogen exposure. High concentration of hydrogen about 0.7 per a tungsten atom was found in the WO3 films. The hydrogen retention drastically decreased with a decrease of the oxygen concentration.
