Anionic effect on the intercalation and spectral properties of poly(butyl viologen) films

摘要

The influence of anions and solvents on the electrochemical and spectral behaviors of poly(butyl viologen) (PBV) thin films were studied. The first and second cathodic peak potentials of the PBV film on an ITO electrode were -0.63 and -1.10 V (vs. Ag/AgCl/sat'd KCl), respectively, due to the formation of a radical cation unit and di-reduced species. Another anodic peak, at 0.30 V indicated that ferrocyanide was immobilized in the film. The electrochemical quartz crystal microbalance (EQCM) method was used to monitor the redox behavior of the PBV film. It was found that both anion and water were removed during reduction and injected during oxidation. The Nernst plot also confirmed the intercalation behavior of the film. Different anions in the electrolyte had various effects on the redox potential of PBV The redox potentials of the PBV film under various anionic conditions showed different orders as compared to that of viologen molecular solutions. The absorbance of the PBV film in the darkened state showed that a high extent of dimer formation had occurred in the aqueous solution compared to that in the propylene carbonate (PC) solution. Moreover the aging effect which occurred in the PC solution caused electrochemical irreversibility.