Conductive Polymer Coated Electrodes for Rapid Electrochromic Switching

The polymer film located between the fingers of a metal grid is a critical element in developing an operational electrochromic switch on a poly(tetrafluoroethylene) substrate. The polymer must be thin and highly conductive in one state to give the switch both a rapid response and a high contrast ratio. In addition, overlap of the polymer onto the top of the grids increases the charge required to switch the polymer and slows down the response time. The objective of the Phase I program is to pretreat the space between the grid with a thin film of a semiconducting material onto which the conductive polymer is electrodeposited. The monomers and electrodeposition conditions are selected to form polymer films with high conductivity in their oxidized state. After deposition of the polymer, the semiconducting material will be made insulating to allow maximum transmission when the switch is in the open state. The conductivity of the films in their conductive and insulating state will be measured as well as their switching speed between the states in a liquid electrochemical cell. In the Phase I Option, the most promising electrode design will be evaluated in a solid state electrochromic switch.