High contrast ratio and fast switching polymeric electrochromic films based on water-dispersible polyaniline-poly(4-styrenesulfonate) nanoparticles

We prepared polyaniline-poly(4-styrenesulfonate) nanoparticles (PANT/PSS-NPs) by chemical oxidation polymerization in aqueous solution. We investigated the potential of the PANT/PSS-NPs to be used as an anode electrode for electrochromic devices and the effect of Li+ insertion (or deinsertion) kinetics and diffusion of Li+. A uniform electrochromic layer of PANT/PSS-NPs with a size of ca. 28 nm could be obtained by a solution process, specifically spin coating. The PANT/PSS-NPs film has a high Li+ diffusion coefficient (similar to 7.7 x 10(-9) cm(2) s(-1)) and low charge transfer resistance (similar to 99 Omega), which result in its having a fast electrochromic response time (coloring time <1.7 s, bleaching time <2.4 s), and high coloration efficiency (>108 cm(2) C-1). (C) 2009 Elsevier B.V. All rights reserved.