A novel alternating polymer, ProDOT-TPE, with aggregation-enhanced fluorescent emission and electrochromic properties based on thiophene and tetraphenylethene derivatives was designed, synthesized, and characterized. The polymer displays weak photoluminescence in tetrahydrofuran, but its corresponding film prepared by spray-coating exhibits yellow-green fluorescent light at 540 nm. The color of the polymer film could be switched from bright yellow to navy blue by applying a relatively low voltage. An electrochromic device (ECD) of the polymer was fabricated that differs from common ECDs because both its color and fluorescent state could be synchronously switched by an applied voltage, making the polymer a unique candidate for electrochemical fluorescence and electrochromic applications.

A highly regiosymmetric homopolymer based on a diethyl malonate derivatized 3,4-propylenedioxythiophene (ProDOT) monomer was synthesized through FeCl3 oxidative polymerization and postpolymerization functionalization to realize a water-processable blue-to-transmissive switching electrochromic polymer (WPECP-blue). As an electrochromic material, the polymer has a high electrochromic contrast ΔTmax=56% at 580 nm and a relatively fast switching speed t95=1.8 s, and shows only contrast loss of 11% (from 56% to 45%) at square wave potential step of 5 s over 11,000 switching cycles, making it a desirable candidate for electrochromic applications such as windows and displays.

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