Influence of PF6 Dopant Concentration on the X-ray Photoelectron Spectroscopy and Ultraviolet Photoelectron Spectroscopy Spectra of Poly 3-methylthiophene

X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy techniques have been used to characterize electrochemically grown conductive films of poly (3-methylthiophene) in the PF₆doped and undoped states. The PF₆dopant concentration was varied between the undoped and fully doped states. Core-level and valence-level spectra have yielded information on the nature of the polymeric cation and its associated PF₆anion, as well as structural disorder effects in these polymers. Results have revealed that addition of the PF₆counterion causes structural disorder within the polymer and that the PF₆counterion interacts with the highest occupied nonbonding lone-pair orbital, as well as causing shifts in the photoelectric threshold which may indicate the formation of bipolaron bands.