Ultra fast electrochromic switching of nanoporous tungsten–tantalum oxide films

Self-organized nanoporous oxide layers were grown on a W–Ta alloy by electrochemical anodization. These nanostructured mixed oxide layers show an ultra-fast electrochromic switching kinetics. Compared with porous WO3 nanostructures more than 10 times higher switching frequencies are reached along with a significantly enhanced lifetime and cyclability.