Six-layer electrochromic devices of indium tin oxide (ITO)/NiOxHy/WO3/ZrP-e
lectrolyte/WO3/ITO were made by reactive dc magnetron sputtering and lamina
tion. The WO3 layer between the acidic ZrP-based electrolyte and the NiOxHy
layer served as optically passive protective layer. The optical inactivity
of the protective layer could be understood from arguments based on electr
on density of states. (C) 2001 American Institute of Physics.