Poly(neutral red), poly(crystal violet), and poly(congo red) films as color filters for producing new color states in polyaniline electrochromic system

Abstract

There is a pressing need for efficient strategies to produce new colors in electrochromic (EC) systems. The majority of studies to date have been conducted on the development of advanced synthesis routes for obtaining desired colors in EC materials, but they suffer from complicated synthesis and high costs. Herein, we developed a facile, viable, and efficient approach for tuning EC behavior of polyaniline (PANI) using three polymeric dyes: poly(neutral red) (PNR), poly(crystal violet) (PCV), and poly(Congo red) (PCR) films as color filters. PNR, PCV, and PCR films were electrodeposited on a fluorine-doped tin oxide (FTO) electrode modified with Schiff base network-1 (SNW1) to fabricate FTO/SNW1/PNR, FTO/SNW1/PCV, and FTO/SNW1/PCR, respectively. To inquire about the effects of studied polymeric dyes on the EC performance of PANI, aniline was electropolymerized onto the modified electrodes. The fabrication of the PANI-based EC electrodes, namely FTO/SNW1/PNR/PANI, FTO/SNW1/PCV/PANI, and FTO/SNW1/PCR/PANI, was characterized using cyclic voltammetry, EIS, FT–IR, XRD, FESEM, TEM and spectroelectrochemical approaches. The EC studies confirmed that FTO/SNW1/PNR/PANI, FTO/SNW1/PCV/PANI, and FTO/SNW1/PCR/PANI electrodes change their color in the oxidized states to pale red, yellowish-green, and blue, respectively, if reduced at − 0.6 V. Combining PANI film with three different polymeric dyes can produce new colors in the reduced state of PANI film. FTO/SNW1/PANI, FTO/SNW1/PNR/PANI, FTO/SNW1/PCV/PANI, and FTO/SNW1/PCR/PANI showed high optical contrasts of 66%, 54%, 64%, and 78%, respectively, at 700 nm. This effort provides a new approach for tuning the EC behavior of PANI and puts forward an idea to produce new colors via organic color filters.