Electrochemical Doping and Dedoping Behaviors of PEDOT-Based Ternary Conducting Polymer Composites with Binary Polymer Surfactants
Jongmyung Eun, Donguk Kim, Felix Sunjoo Kim
Abstract
We report the synthesis and characterization of a series of conducting polymer composites based on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate):poly(vinyl sulfonate) (PEDOT:PSS:PVS) with various PSS:PVS ratios and their applications in organic electrochemical transistors. PVS, as a secondary polymer surfactant, is compatible with ternary composites, with a readily adjustable PSS/PVS ratio through the feed ratios. The ternary composites exhibit similar ultraviolet–visible (UV–vis) absorption characteristics of highly doped PEDOT chains as those in a binary PEDOT:PSS composite, with an electrical conductivity of 120–180 S/cm and very smooth surface morphology. Electrochemical transistors based on the composites as channels and an ion gel as an electrolyte layer show good current modulation. The spectroelectrochemical and quantitative analyses of modulated charge-carrier density revealed that the PSS/PVS ratio is an important factor governing the effectiveness of electrochemical doping and dedoping under electrolyte-based gating. Our findings suggest that the addition of PVS in a PEDOT:PSS composite can be an effective strategy to control the internal ion-transport properties without sacrificing their excellent electrical and film-forming properties.