Photoelectron Spectra of Polypyrrole: The Effect of the Ambient Atmosphere to the Spectra

Abstract

Abstract Ultraviolet and X-ray photoelectron spectra of carefully prepared undoped as well as doped polypyrrole have been measured. Reliable UPS of undoped polypyrrole must be the first one in spite of its popularity, because of its instability in the air. Our UPS were compared with those of presumably polymerized pyrrole by X-ray irradiation and other reported results. We examined the validity of these spectra and we found the deformation of the UPS caused by air exposure of the undoped film. A comparison of our UPS with theoretical calculation gave 1.40 Å as an estimated bond distance between α,α′ carbon atoms. Both Cls and Nls XPS were asymmetric and consisted of a few peak components, which was not dependent on doping. Their peak envelopes varied with its historical back ground. While the Cls peak envelopes were not deformed so seriously by air exposure, the Nls envelopes were affected by slight air exposure as were observed in the UPS.