A large contrast ratio and rapid switching EC polymer device which consists of a laminated two-layer structure between two electrodes was prepared. The new design consists of an ITO glass electrode, a cathodic EC polymer film, a gel electrolyte and a counter-electrode that replaces the anodic EC polymer and ITO electrode. Several types of EC polymers, such as, poly[3,3-dimethyl-3,4-dihydro-2H-thieno(3,4-b)(1,4)dioxepine] (PProDOT-(CH3)2) and
poly[3,4-(2,2-dimethylpropylenedioxy)-pyrrole] (PProDOP-(CH3)2) were synthesized as cathodic EC polymers. A carbon-based counter-electrode was prepared for comparison with an Au-based counter-electrode. Screen-printing was utilized for the carbon-based counter-electrode. Lithography and sputtering were used for the Au patterned glass counter-electrodes. Several kinds of polymer gel electrolytes were prepared for solid-state applications. Color change of high contrast ratio of visible light transmittance (>ΔΤ55%)of the device is rapidly obtained (0.5-1s) when even less than 2.5V is applied. The repeatability of color changeable EC polymer windows was estimated by the method of electrochemistry and spectrophotometry. This "smart window" technology can be used in many applications where a rapid
color change between transparent and color states is required.
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