Is the Enhanced Adhesion of PEDOT Thin Films on Electrodes Due toSulfur - Gold Interaction? - An XPS Study

摘要

Electrode materials obtained through electropolymerization of 3,4-ethylenedioxythiophene (EDOT) havesparked interest toward applications in neuroscience and neuroprosthetics due to their favorable electrochemicalproperties and their biocompatibility. However, insufficient mechanical stability had been an unresolved issue andhindered practical applications, until recent research by our group demonstrated proper adhesion of poly(3,4-ethylenedioxythiophene) (PEDOT) to a gold surface. In the present study, X-ray photoelectron spectroscopy (XPS) wasemployed and in particular the chemical shift of the S2p band, which is indicative of binding between sulfur and gold, wasused to assess the degree of interaction between 3,4-ethylenedioxythiophene (EDOT), thiophene, and 3-thiophenecarboxylic acid (thiophene-COOH), with the gold surface. The results of the XPS investigations indicate acovalent bond between EDOT and gold, which should indeed contribute to improved adhesion.