Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonic Acid) (PEDOT:PSS) Conductivity Enhancement through Addition of Imidazolium-Ionic Liquid Derivatives

Here, insignificant conductivity enhancement of PEDOT:PSS through adding different amounts of 2-methylimidazolium ionic liquids into PEDOT:PSS aqueous solutions is reported. Maximum conductivity was reached through 2-methylimidazolium hydrogen sulfate (5 wt.%) addition. It seems that observed conductivity enhancement mainly results from the impact of ionic liquids on the electrical properties and conformational change of PEDOT chains, and through weakening of the electrostatic interactions between PEDOT and PSS. Also, better conductivity was achieved through weak interactions between PEDOT and the PSS chain, which changes the PEDOT conformation and further delocalizes the polarons, as well as changes the electron transport properties.