*** 9710491 Cogan This Small Business Innovation Phase II project will develop thin-film electrochromic materials that provide enhanced color control. Electrochromic materials change their optical properties reversibly when electrochemically cycled between oxidized and reduced forms. A new concept in electrochromic materials design based on bilayer or multilayer contiguous thin films of electrochromic inorganic oxides was investigated in Phase I. Electrochromic coatings that modulate over a range of colors, e.g., yellow-neutral-blue or gray-neutral, were identified. A model was developed to predict the color and spectral properties of multilayer electrochromic coatings and devices based on the spectroelectrochemical properties of the individual layers. Model predictions for bilayer coatings were confirmed by comparison with experimental data. In Phase II, the multilayer coatings would be incorporated into thin film electrochromic devices designed for modulating solar transmittance through building windows. Spectroelectrochemical measurements of individual and multilayer coatings would be used with the model to design devices with near-neutral optical modulation and wide luminous and solar transmittance range. In addition, two and three-color electrochromic displays would be developed using the model and the accumulated database of spectroelectrochemical properties of the oxides investigated to guide the display design. Commercial applications sought in Phase II are architectural solar control coatings exhibiting near-neutral visible modulation and multicolor electrochromic displays. ***
