Doping of Polyaniline in the Solid State with Photogenerated Triflic Acid

Abstract

The objective of this study was to adjust work function of polyaniline (PANI) in the solid state by precisely dosed UV irradiation. For this purpose triphenylsulfonium triflate salt was used as a photo acid generator. The structure of PANI before and after irradiation was characterized by UV−vis and FTIR spectroscopy. It has been observed that the appearance of the 1143-cm-1 band, corresponding to the polaron stretching mode, correlates with the changes of the Fermi level. This observation indicates that electrons in the proton-doped PANI are delocalized, leading to a change in the electronic structure of PANI. The changes result in lowering of the work function of PANI as measured by the field-effect transistor. Nondecomposed triflate salt can be removed by dipping the irradiated film into methanol to prevent further UV light sensitivity and further postexposure acid doping.