Polymer-based symmetric electrochromic devices

The fact that conjugated polymers repeatedly undergo electrochemical doping/undoping processes, which are accompained by color changes, makes these materials very attractive, and much effort has been devoted to their use in advanced devices. There is renewed interest in electroactive polymers that reversibly undergo both p- and n-doping because of their potential application in symmetric electrochemical devices. We employed fused molecules, dithienothiophenes, as monomers to obtain polymers with a narrow band gap suitable for n- and p-doping. The performance results of two symmetric electrochromic devices having as electrodes both poly(dithieno[3,4-b:3',4'-d]thiophene) (pDTT1) and poly(dithieno[3,4-b:2',3'-d]thiophene) (pDTT3) are reported and discussed. © 1999 Elsevier Science B.V. All rights reserved.