Electrochromic Polymers Processed from Environmentally Benign Solvents

Abstract

The ability to process conjugated polymers from environmentally benign solvents is essential for making organic electronics commercially viable by reducing costs and enhancing safety in the printing and processing environment. To enhance the solubility of typically alkyl-functionalized redox-active and electrochromic polymers, poly(3,4-propylenedioxythiophenes) with ester-functionalized side chains were synthesized via direct arylation polymerization, resulting in polymers that are processable from 2-methyltetrahydrofuran, ethyl acetate, and propyl acetate. Optical and atomic force microscopy results of spray-processed films indicate that topological features, such as film roughness, can be manipulated via the vapor pressure of the processing solvent. The solvent choice affects the resulting onset of absorbance and relative intensities of vibronic features, which translates into distinctly observable and quantifiable color differences. While the color is sensitive to the casting solvent, the redox prope...