A Facile Electrochemical Strategy for Achieving a High-Conductivity Polypyrrole Derivative with Intrinsic Metallic Transport as a High-Performance Electrochromic Conducting Polymer Film

Conjugated polymer electrochromic materials (PECMs) with tailored optical and electrical properties are applied in smart windows, electronic displays, and adaptive camouflage. The limitation in the electrical conductivity results in slow and monotonous color switching. We present a polypyrrole film incorporated with a toluene-<i>p</i>-sulfonic group (PPy-TSO-F), via a one-step electrodeposition technique. The PPy-TSO-F thin film (110 nm) achieves an impressive electrical conductivity of 1011 S cm^-1, a high carrier mobility of 82 cm² V^-1 s^-1, and intrinsic metallic electronic behavior. It demonstrates exceptionally reversible multicolor switching, transitioning from emerald green (-1.5 V), to bluish green (-1.4 V), bright yellow (-1.2 V), greenish yellow (-0.6 V), reddish brown (0.1 V), dark brown (0.3 V), and atrovirens (0.6 V). The fast charge transport and high carrier mobility render the film with an ultrafast electrochromic switching speed of 0.01 s/0.02 s. This research provides a new route to designing ultrafast multicolor switching PECMs with metallic charge transport.