The electronic structure of polyaniline and doped phases studied by soft X-ray absorption and emission spectroscopies

The electronic structure of the conjugated polymer, polyaniline, has been studied by resonant and nonresonant X-ray emission spectroscopy using synchrotron radiation for the excitation. The measurements were made on polyaniline and a few doped (protonated) phases for both the carbon and nitrogen contents. The resonant X-ray emission spectra show depletion of the {\pi} electron bands due to the selective excitation which enhances the effect of symmetry selection rules. The valence band structures in the X-ray emission spectra attributed to the {\pi} bands show unambiguous changes of the electronic structure upon protonation. By comparing to X-ray absorption measurements, the chemical bonding and electronic configuration is characterized.