Fast Visible-to-Infrared Electrochromic Devices Based on Electrochemically Fabricated Polyaniline

Polyaniline-based electrochromic devices exhibit excellent adaptive camouflage potential in both visible and infrared spectral regions, but they currently still suffer from a slow response issue. Here, a fast visible-to-infrared electrochromic device based on electrochemically fabricated [BSO₃]Py·HSO₄-doped polyaniline is demonstrated. The electrochromic device achieves an ultrafast electrical response time of 0.5 s for coloration and 0.9 s for bleaching as well as maximum emissivity modulation of 0.35 in 3–5 μm and 0.51 in 8–14 μm bands. The device is fabricated by direct electrochemical polymerization of aniline monomers on Au-plated nylon porous electrodes with mixed ionic liquids of [BSO₃]Py·HSO₄/[BMIM]BF₄ simultaneously as acidic precursor solution and gel electrolyte, termed as a one-step device fabrication method. Importantly, the one-step device fabrication combines the high ion diffusion rate of [BSO₃]Py·HSO₄-doped polyaniline film, the high ionic conductivity of an ionic liquid electrolyte, and improved electrolyte wettability, providing an advanced device fabrication strategy for adaptive camouflage applications.