Influence of Ambient Humidity on the Conductivity Enhancement of PEDOT:PSS Films during the Acetic Acid Treatment

Abstract

In this work, well-controlled ambient humidity can adjust the conductivity of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films during an acetic acid rinse. The conductivity of PEDOT:PSS films can be dramatically enhanced by optimizing post-treatment ambient humidity. The conductivity of PEDOT:PSS films increase from 0.33 S/cm for the pristine to 1090 S/cm at relative humidity (RH) of 60% while that of PEDOT:PSS films is only 5.04 S/cm at H2O < 1 ppm. The improvement conductivity should be attributed to enhanced phase segregation, removing of some PSS chains from PEDOT:PSS and reorganization of PEDOT chains at higher RH. This facile solvent-treated route provides a promising transparent electrode fabrication method to replace ITO electrode in organic photovoltaics (OPVs).