Ionic liquids in electrosynthesis and characterization of a polyazulene-fullerene composite

Polyazulene (PAz) was electrosynthesized in the ionic liquid N,N-butyl-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide (BMP]Tf₂N]) and characterized using electrochemical methods. By using BMP]Tf₂N] as the electrolyte we obtained films with improved electrochemical and morphological properties compared to films electrosynthesized in an acetonitrile-based electrolyte solution. Composite films consisting of drop cast C₆₀ and electrosynthesized PAz were also investigated in BMP]Tf₂N] using electrochemical methods, UV–vis and SEM and the results were compared to similar films prepared in acetonitrile. The use of ionic liquids made it possible to study the redox reactions of C₆₀ at room-temperature and in an extended cathodic potential range. In comparison to pure PAz the presence of C₆₀ in the composite film improved the charge storing ability. Electrosynthesis in BMP]Tf₂N] resulted in composite films with a lower degree of charge trapping compared to composite films synthesized in organic media.