Electrochromic Behavior of Donor-Acceptor Polymers Containing Diketopyrrolopyrrole Unit

Abstract

Donor-acceptor polymers composed of the electron-rich fluorene or triphenylamine unit and electron-deficient diketopyrrolopyrrole (DPP) unit were investigated. These polymers showed an intense low-energy visible absorption in their neutral film states. The films of all the polymers displayed both oxidation and reduction waves in their cyclic voltammograms due to their narrow bandgaps. Both the anodic and cathodic electrochromic behaviors were investigated and compared to those of the reported DPP-based polymers. The results were explained by the difference in the comonomer structures. In addition, the switching times during the cathodic electrochromism were reported.