Formation of polystyrene sulfonic acid surface structures on poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) thin films and the enhancement of its conductivity by using sulfuric acid

► Sulfuric acid addition to poly(3,4-ethylenedioxythiophene) (PEDOT) solutions ► Formation of poly(styrenesulfonate) (PSS) structures on PEDOT:PSS films is observed. ► An enhancement in the conductivities of PEDOT:PSS films was obtained. ► Optical spectroscopies suggest the incorporation of bisulfate ions in the films. ► High quality doped films were obtained.