Regensburg 2019 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 12: Poster session I
MM 12.27: Poster
Monday, April 1, 2019, 19:15–20:45, Poster C
Characterization of diffusive transport in polycrystalline tungsten trioxide thin films — •Jan L. Dornseifer1,2, Alexander G. Strack1,2, Simon Burkhardt1,2, Matthias T. Elm1,2,3, and Peter J. Klar1,2 — 1Institute of Experimental Physics I, Justus-Liebig-Universität, Germany — 2Center for Materials Research (LaMa), Justus-Liebig-Universität, Germany — 3Institute of Physical Chemistry, Justus-Liebig-Universität, Germany
Tungsten trioxide (WO3) is an electrochromic material, thus, it can change its optical properties through insertion of charge carriers. Its electrochromic properties depend on the deposition process and resulting morphology. Polycrystalline WO3 thin films are prepared by electron-beam evaporation and a subsequent heat treatment at 450 ∘C. To investigate the diffusive transport of hydrogen in WO3, the electrochemical properties are estimated by measurments using the galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS). The impedance spectra obtained are fitted with a Randles circuit. The self-bleaching of WO3 influences the experimental data in a significant way which has an impact on the evaluation of the data and the determination of the diffusion coefficients. In situ transmission measurements during the impedance spectroscopy reveals an oscillating behavior of the transmission at excitation signal frequencies below 91 mHz. This interesting behavior may yield additional information about the diffusive ion transport.