High-performance transistors for bioelectronics through tuning of channel thickness

Area of Science:

• Materials Science
• Bioelectronics
• Organic Electronics

Background:

• Organic electrochemical transistors (OECTs) are gaining interest due to their simple fabrication and high performance.
• OECTs integrate a polymer channel with an electrolyte, facilitating biological applications.
• The fundamental operating mechanisms of OECTs, particularly ion exchange, are not fully understood.

Purpose of the Study:

• To investigate the impact of ion exchange on OECT characteristics.
• To explore the relationship between ion uptake and device performance.
• To leverage these findings for improved bioelectronic applications.

Main Methods:

• Fabrication of organic electrochemical transistors using poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS).
• Characterization of ion uptake into the PEDOT:PSS channel.
• Measurement of device transconductance and its dependence on channel thickness.
• Demonstration of OECTs for recording human brain rhythms.

Main Results:

• Ion uptake into PEDOT:PSS films results in a significant volumetric capacitance (39 F/cm³).
• Device transconductance is found to be dependent on channel thickness, offering a new design parameter.
• High-quality recordings of human brain rhythms were achieved using these OECTs.

Conclusions:

• Ion exchange is a critical mechanism influencing OECT performance.
• The volumetric capacitance arising from ion uptake provides a tunable characteristic.
• This work offers a pathway for designing advanced OECTs with performance independent of device footprint, suitable for bioelectronic applications.