Electrochemical Doping and Dedoping Behaviors of PEDOT-Based Ternary Conducting Polymer Composites with Binary Polymer Surfactants

Wereport the synthesis and characterization of a series of conductingpolymer composites based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate):poly(vinyl sulfonate) (PEDOT:PSS:PVS) with various PSS:PVSratios and their applications in organic electrochemical transistors.PVS, as a secondary polymer surfactant, is compatible with ternarycomposites, with a readily adjustable PSS/PVS ratio through the feedratios. The ternary composites exhibit similar ultraviolet-visible(UV-vis) absorption characteristics of highly doped PEDOT chainsas those in a binary PEDOT:PSS composite, with an electrical conductivityof 120-180 S/cm and very smooth surface morphology. Electrochemicaltransistors based on the composites as channels and an ion gel asan electrolyte layer show good current modulation. The spectroelectrochemicaland quantitative analyses of modulated charge-carrier density revealedthat the PSS/PVS ratio is an important factor governing the effectivenessof electrochemical doping and dedoping under electrolyte-based gating.Our findings suggest that the addition of PVS in a PEDOT:PSS compositecan be an effective strategy to control the internal ion-transportproperties without sacrificing their excellent electrical and film-formingproperties.