Dynamic Modulation of OECT-Based Inverters for In Situ Electrophysiological Monitoring

Organic electrochemical transistors (OECTs) and their related circuits have emerged as a promising platform for biosensors and neuromorphic electronics, benefiting from their sub-1 V operation voltage, flexibility, biocompatibility, etc. However, operation instability, induced by complex microstructure variations and undesired side reactions during repeated redox processes, poses tremendous challenges for reliable and robust functions. Here, a dynamic modulating system is presented that can actively control the working condition of an OECT-based inverter and maintain high-voltage amplification capability through real-time voltage transfer characteristic scanning and operating voltage adjustment. Especially, under system modulation, the inverter maintains a high-voltage amplification capability with a voltage gain >34.58 V V^-1. While without modulation (i.e., at a fixed input voltage), the voltage gain rapidly deteriorates to 3.11 V V^-1. Thereafter, stretchable complementary circuits are fabricated and integrated with this system to enable high-fidelity in situ monitoring of the electrooculogram with >32.59 dB signal-to-noise ratio for more than 90 min, thus establishing a reliable wearable biosensing method. This work provides a new strategy to enable highly stable operation of bioelectronics with devices holding inferior stabilities.