Impact of Ionic Species on the Performance of Pedot:PSS‐Based Organic Electrochemical Transistors

Abstract

The organic electrochemical transistor (OECT) has received considerable interest in the field of bioelectronics due to its ability to support both ionic and electronic transport. However, the fundamental aspects of the OECT's operation are not yet fully understood. Here, the impact on the performance of poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)‐based OECTs, of a series electrolytes with chloride‐based ions is evaluated, varying their cation counterpart under the extension of the Hofmeister Series. Electrical results are analyzed using the Bernards‐Malliaras and Faria‐Duong models and correlated with quartz crystal microbalance measurements. It is shown that cations with a higher ability of salting‐in, according to the Hofmeister series, swell the channel with higher efficiency. In addition, cations with a higher ability to salt‐out promote smaller modulations in the channel's current, indicating that the ionic transport in the bulk of the channel is directly correlated with the swelling ability of the film. Overall, the results provide a better understanding of the interplay of channel and electrolyte in OECTs and promote guidelines for optimizing materials choice for highly sensitive OECTs.

3D printed bioelectronic scaffolds with soft tissue-like stiffness

“…Hydrogels of PEDOT:PSS have been made from its colloidal dispersions (1.1 -1.3 wt%) by mixing with ionic liquids (IL) and allowing to gel with time at room or elevated temperatures 42,43 . Ionic liquids induce gelation by performing charge screening of PEDOT and PSS, thereby promoting structural rearrangement of PEDOT and the formation of physical cross-links including through π-π stacking 44 . Our previous work has shown that specific concentrations of ionic liquid (>10 mg/mL) result in mixtures which transition from liquid to gel on a timescale of minutes to hours 42 .…”