Significant conductivity enhancement of PEDOT:PSS films treated with lithium salt solutions

An effective method to significantly enhance the electrical conductivity of PEDOT:PSS films through a treatment with various aqueous solutions of lithium salts such as LiClO4, Li2SO4 and LiNO3 etc., is presented in this paper. The maximum electrical conductivity of PEDOT:PSS film treated with LiClO4 could be up to 522 S cm(-1), which was enhanced by a factor of 2,610 compared to that of pure PEDOT:PSS film (0.2 S cm(-1)). The FTIR spectra characterization was performed and suggested that the chemical structure of PEDOT:PSS didn't change after the treatment. Remarkable improvement in carrier mobility was a key reason for the increase in the electrical conductivity. The highest carrier mobility of the PEDOT:PSS film by LiClO4 treatment could reach 3.8 cm(2)/Vs, approximately 15 times higher than that of pure PEDOT:PSS film with a value of 0.25 cm(2)/Vs.