Improved Electrochromic Performance of Poly(3,4-ethylenedioxythiophene) by Incorporating a Three-Dimensionally Ordered Macroporous Structure

In this paper, three-dimensionally ordered macroporous (3DOM) poly(3,4-ethylenedioxythiophene) (PEDOT) films were electropolymerized from an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF₆). The electrochromic performances of the 3DOM PEDOT films were studied. The 3DOM films exhibited high transmittance modulation (41.2 % at λ=580 nm), high ionic fast switching speeds (0.7 and 0.7 s for coloration and bleaching, respectively), and enhanced cycling stability relative to that exhibited by the dense PEDOT film. The relationship between the declining behavior of the transmittance modulation and the nanostructure of the film was investigated. A three-period decay process was proposed to understand the declining behavior. The 3D interconnected macroporous nanostructure is beneficial for fast ion and electron transportation, high ion accessibility, and maintenance of structure integrity, which result in enhanced cycling stability and fast switching speeds.