Polypyrrole Color Modulation and Electrochromic Contrast Enhancement by Doping with a Dye

Conjugated polymers that exhibit color changes on being switched between the conducting and insulating forms hold promise for applications in electrochromic devices. With the aim of increasing the electrochromic color contrast of polypyrrole/dodecylsulfate (PPy/DS) films and investigating a possible modulation of the color change, the colored dopant indigo carmine, a water-soluble dianionic dye, was added to PPy and PPy/DS films. The effects on the electrochromic properties of the films and on their morphology and homogeneity are reported.