关键词: 聚苯胺, 电致变色, 光电性能, 循环性能

Abstract: The electrochromic behaviors of polyaniline films were investigated by potential step and cyclic voltammetry coupled with UV viscosity photometer. The polyaniline films show colorful changes from pale yellow to green and then to blue. Electrochromic stability, electrochemical behavior, coloring performance, optical properties and surface formations of the produced films were studied in detail. The working electrode was the flexible PANI electrode, and the counter electrode and the reference electrode were a platinum sheet and Ag/AgCl, respectively. The in situ optical transmittance of the PANI film at 650 nm was measured using an ultraviolet-visible-near-infrared spectrophotometer (Shimadzu UV-3101PC) combining with a square quartz tank during all electrochemical cycling. The electrochemical tests were performed on a Princeton Versa STAT 4 electrochemical workstation. The electrochromic performance of polyaniline films has been studied using cyclic voltammetry and chronoamperometry over the potential window of -0.2 to 1.2 V in 1 mol·L^-1 LiClO₄⁺ propylene carbonate. The polyaniline films exhibited electrochromism with color that changed from pale yellow (Leucoemeraldine base at 0.4 V) to dark green (Emeraldine salt at 0.8 V) to dark blue (Emeraldine base at 1.2 V) in their oxidized states. This work reports the electrochemical cycling stability of polyaniline films in different color change intervals. It was found that the chronoamperometric current did not change significantly in the interval from yellow to green. In addition, the charge amount changed steadily and the electrochromic performance of the film was good. The electrochromic cycle performance was poor when the film changed from yellow to blue as well as green to blue. While in the interval from yellow to green on switching between 0.4 and 0.8 V, the electrochemical cycling stability was good; the response time of the film for the coloring was found to be 4.5 s and the coloring efficiency of the polyaniline film was observed to be 159.48  cm²·C^-1.

Key words: polyaniline, electrochromism, optoelectronic performance, cyclic performance