Optical and Electrochromic Properties of Electrochromic Windows (ECW) Based on PProDOT-Me2 and V2O5 Coating

The average office building uses a significant amount of power for heating and cooling. Reducing the amount of light entering a building has a drastic effect on the amount of energy required to cool it. ECWs are a developing technology specifically created to provide an easy, automated way to reduce a building’s energy consumption by shading the window from incoming sunlight. When an electric current is applied, the ECW reversibly changes color from transparent to opaque. ECWs are composed of three primary components: electrochromic, ion conducting, and ion storage layers. The electrochromic layer contains a polymer that changes its optical properties in the presence of lithium ions. The ion conducting layer uses a lithium ion electrolyte to transfer charge between layers. The ion storage layer balances the charge between layers allowing the electrochromic layer to stay in its opaque or transparent state. The most important variables in the synthesis of ECWs include the deposition time, moisture and oxidation levels, and deposition solution concentrations for the electrochromic and ion conducting layers. Of these variables, this experiment will focus primarily on the deposition time. The researcher will produce a large sample set of ECWs based on PProDOT-Me₂ and V₂O₅ coatings, which will be tested for the most important ECW characteristics: the charge capacity, switching speed, and contrast levels. From analyzing this data the most favorable properties of the electrochromic and ion storage layers can be determined, which can lead to the production of an optimized ECW with controlled and reproducible optical characteristics.