Electroabsorption measurements of the emeraldine base form of polyaniline

Electroabsorption measurements have been performed on the polymeric emeraldine base form of polyaniline and a related phenyl-capped tetramer. The spectra ran from the near infrared to the UV, encompassing the main low energy absorption peaks of the materials. The lineshapes of the spectra closely resemble each other, indicating that the electronic structure of the two are similar. The results also indicate that the state produced upon 2 eV photoexcitation is, to some degree, spatially extended. The data for the phenyl-capped tetramer show a small signal below the main peak in the electroabsorption which could possibly be assigned to a transition of oscillator strength to a normally optically forbidden transition.