We have fabricated two types of Electrochromic multilayers using ionic conductive polymeric electrolyte and solid state electrolyte. All thin films were deposited by reactive rf-magnetron sputtering and their optical transmittance was measured.
To obtain electrochromic layer, we deposited $WO_3$, NiO, IrO on ITO. For electrochromic property, non-stoichiometric phase of each film was needed. Therefore, we controlled $O_2$ pressure and other conditions to obtain relatively good films.
We also fabricated two types of electrochromic multilayer system. One has ionic conductive polymer as electrolyte layer and complementary electrochromic layers of cathodic $WO_3$, and anodic NiO. The other system has solid state ionic conductor, $Ta_2O_5$ and complementary electrochromic layers of cathodic $WO_3$, and anodic IrO. Fabricated systems leave some problems to be solved, most of which are considered to be related to electrolyte and its surroundings. Detailed processes and mechanisms are to be studied further.
