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John Reynolds1 Chi Kin Lo1 Anna Österholm1 Lisa Savagian1 Dwanleen Shen1

1, Georgia Institute of Technology, Atlanta, Georgia, United States

Encouraged by the commercial utility of organic molecular electrochromes in electrochromic windows and mirrors, we are developing scalable and solution processable conjugated electrochromic polymers (ECPs), which provide a unique encompassing set of structurally tunable colorimetric and redox properties, stable over thousands and tens of thousands of redox switches. Processing of these materials is carried out using a variety of solution methods including spin-coating, spray-coating, blade-coating, slot die coating, and ink jet printing. In this lecture, we demonstrate how the optical absorbance spectra of ECPs can be tuned to yield materials of all colors that can be switched to highly transmissive forms as desired for absorptive/reflective (display type) and absorptive/transmissive (window type) devices. We will show how random copolymerization has been used to broaden spectral absorption yielding a family of black-to-transmissive ECPs. We have also developed a set of fast switching, high contrast, black and brown ECP blends, where the precise hues are readily tunable. We use these brown blends to showcase a practical application of ECPs in color changing eyewear. In addition to their aesthetic qualities, their optical memory in both the colored and colorless states allow these devices to be run at low power. Photo-oxidative stability will be addressed using encapsulated films and ECDs. Finally, we combine our ECP and OPV technologies into possibilities for solar powered electrochromic windows.

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