Influence of pH on the electroactivity of polycarbazole

Spectrochemical properties and charge released by electrochemically synthesized polycarbazole films on indium-tin oxide-coated glass plates have been investigated in perchloric acid as a function of pH and oxidation potential (Vox). At pH ⩽ 2 the peak intensities at 350 and 738 nm increase up to a certain potential whereafter a distinct decrease in respective peak intensities has been observed. At 2 < pH ⩽ 4 the observed electronic spectra do not exhibit any change on application of the oxidation potential. The charge released by the polymer decreases with increasing pH on application of a potential difference and attains a minimum at pH 3 indicating that deprotonation in this conducting polymer is perhaps complete at this value of pH.