High-sensitivity ion detection at low voltages with current-driven organic electrochemical transistors

Area of Science:

• Electrochemistry
• Materials Science
• Biomedical Engineering

Background:

• Ions in aqueous media are vital for biological systems and environmental processes.
• Accurate in situ ion quantification is crucial for diagnostics, environmental monitoring, and industry.
• Current transistor-based ion sensors face limitations in sensitivity, range, and operating voltage.

Purpose of the Study:

• To overcome the limitations of existing transistor-based ion sensors.
• To develop a novel configuration for highly sensitive ion quantification.
• To demonstrate a new approach for bioelectronic applications.

Main Methods:

• Utilized a current-driven configuration with organic electrochemical transistors.
• Developed a novel transistor design to enhance ion sensitivity.
• Measured ion sensitivity against the Nernst limit and normalized to supply voltage.

Main Results:

• Achieved ion sensitivity exceeding the Nernst limit by one order of magnitude.
• Demonstrated high ion sensitivity at low operating voltages (hundreds of millivolts).
• Reported a normalized ion sensitivity exceeding 1200 mV V^-1 dec^-1, a record for ion-sensitive transistors.

Conclusions:

• The proposed current-driven transistor configuration overcomes fundamental limits in ion sensing.
• This approach offers unprecedented sensitivity and performance for ion-sensitive transistors.
• The technology is adaptable to various transistor types, paving the way for advanced bioelectronics.