Electrochemical Performance of PEDOT:PSS Stimulation Electrodes

Safe and effective neural stimulation requires sufficient charge injection without damaging the electrode and tissue. Soft electronic materials such as the commonly used conducting polymer PEDOT:PSS have been introduced to improve bio-interfaces, however, much remains unknown about its ability to safely inject charge. In this work, we examined the electrochemistry of PEDOT:PSS and more specifically the electron transfer processes that take place under various conditions. We studied the influence of electrolyte composition as well as the applied stimulation parameters on reversible and irreversible events. I will discuss important properties of PEDOT:PSS such as the undesired generation of reactive oxygen species, the potential dependent capacitance, and the accessibility of charge that is stored within the conducting polymer network. The results describe the interactions occurring at the electrode-electrolyte interface which is curcial for understanding the stimulation performance of PEDOT:PSS for safe and long-term functional human-machine interfaces.