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Single-layer electrochromic polymer technology for automotive and architectural glazing light control
DuPont
DuPont has successfully developed a less complex, lower cost electrochromatic (EC) technology for controllable light transmission in automotive and architectural safety glazing applications. It is based on an organic polymer film that can function as a controllable EC interlayer. This technology addresses the need for reducing the complexity of current EC technologies and can be used in rigid and flexible forms, large sizes, and curved shapes. It has applications in dynamic electrochromic glazing systems that undergo a reversible change in color from light to dark by application of a very low voltage. Target markets in automotive include sunroofs, mirrors, instrument clusters, windshield shadebands, sidelights and backlights. For the architectural market opportunities include skylights, office partitions, windows and curtain walls.
How it’s different
Today’s EC device construction is complex, with no cost-effective options. Such construction consists of multiple layers, each of them incorporating a specific functionality: the electrochromophore, the electrolyte and the ion storage layer. In addition, in most of these conventional devices, the electrolyte layer is a liquid or a gel. This can cause problems including solvent evaporation and leakage. The versatility of current EC device systems for use in rigid and flexible forms is also limited.
DuPont EC technology is ideally suited to address current needs along with high potential for further development and versatility in diverse applications. It offers an economical solution that could lead to important cost advantages in comparison to current technologies. The EC device construction is simplified, the number of layers is reduced, and the system does not uses liquid or gel electrolytes. This is an all-solid system with a single interlayer that is electrochromically/electrolytically and ionically functional.
The technology can work either in transmissive or reflective mode. Transmissive EC devices are made with indium tin oxide electrodes that are fully transparent in the visible spectral range. Examples of reflector electrode materials include metallic conductors such as rhodium alloy or chromium. The electrochromic film layer can perform a dual role, such as electrochromophore and an electrolyte. All of the components of the electronic control systems are commercially available. Some development work needs to be done to optimize the power profile of the controllers.
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