Berlin 2024 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 33: Transport in Materials: Diffusion, Conduction of Charge or Heat III
MM 33.1: Vortrag
Mittwoch, 20. März 2024, 10:15–10:30, C 264
Correlation of structural changes and hydrogen diffusion in polycrystalline WO3 thin-films by combining in situ transmission measurements and Raman spectroscopy — •Tim K. Hecker, Markus S. Friedrich, Alexander G. Strack, Paul Tuchecker, and Peter J. Klar — Institute of Experimental Physics I and Center for Materials Research, Justus Liebig University Giessen, Giessen, Germany
To better understand hydrogen diffusion in tungsten trioxide thin films, such samples were microstructured with a PMMA film in such a way that the contact surface with the electrolyte is limited to a narrow stripe-like gap. This allows us to study the lateral diffusion of hydrogen under the PMMA film, increasing the analysable path and time scale by several orders of magnitude and thus significantly improving the spatial and temporal resolution of in-situ transmission and Raman measurements. Spatially resolved transmission measurements in the wavelength range of 633±55 nm show that the investigated diffusion is dependent on the hydrogen concentration. Time-resolved Raman measurements with a 633 nm laser at different distances from the electrolyte contact area show that the transition between the two diffusion coefficients is characterised by a phase transition of the crystal structure to higher symmetry. The results are also supported by a spatially and temporally resolved diffusion simulation. In addition, the measurement method presented here is universally applicable.
Keywords: concentation dependent diffusion; hydrogen diffusion; in situ transmission spectroscopy; in situ Raman spectroscopy; tungsten trioxide