High-performance transistors for bioelectronics through tuning of channel thickness

TLDR

Organic electrochemical transistors (OECTs) use an electrolyte in direct contact with a polymer channel, enabling facile integration with biological environments, but the fundamental ion‑exchange mechanism and its effect on device performance remain largely unexplored. The study demonstrates that tuning the channel thickness of poly(3,4‑ethylenedioxythiophene):polystyrene sulfonate films modulates ion uptake and thereby enhances transducer performance.

Abstract

Despite recent interest in organic electrochemical transistors (OECTs), sparked by their straightforward fabrication and high performance, the fundamental mechanism behind their operation remains largely unexplored. OECTs use an electrolyte in direct contact with a polymer channel as part of their device structure. Hence, they offer facile integration with biological milieux and are currently used as amplifying transducers for bioelectronics. Ion exchange between electrolyte and channel is believed to take place in OECTs, although the extent of this process and its impact on device characteristics are still unknown. We show that the uptake of ions from an electrolyte into a film of poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (