Dresden 2011 – scientific programme
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DS: Fachverband Dünne Schichten
DS 20: Application of Thin Films
DS 20.8: Talk
Tuesday, March 15, 2011, 12:00–12:15, GER 38
Ultra fast electrochromic switching of nanoporous tungstentantalum oxide films — •Robin Kirchgeorg, Steffen Berger, and Patrik Schmuki — Institute for Surface Science and Corrosion (LKO), Department Material Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 7, 91052 Erlangen, Germany
Self-organized anodic oxide nanostructures have attracted remarkable scientific interest within the last decades. Due to their unique properties, the applicability of these materials were explored in numerous applications, such as in electrochromic devices. The benchmark for electrochromic materials nowadays is WO3. However, these anodically fabricated WO3 electrodes still lack cycling stability and performance. Recent results on anodic oxides grown on TiW, TiMo and TiNb alloys indicate a significant enhancement of the stability by the formation of oxide composites, but with the fundamental electrochromic properties being considerably poorer than for pure WO3. Self-organized nanoporous oxide layers on a W-Ta alloy grown by anodization in a flouride containing electrolyte, show drastically enhanced electrochromic properties combined with high cycling stability. These self-organized, nanostructured, mixed oxide layers show an ultra-fast electrochromic switching behaviour. Up to more than 10 times higher switching frequencies are reached along with a significantly enhanced lifetime and cyclability. The presentation will provide a comparison of anodically selforganized nanostructures of WO3 and a W-Ta alloy, regarding their electrochromic properties and cycling stability.