Compact Paper-Based Quasi-Solid-State Organic Electrochemical Transistor (QSS-OECT) for Sensing Hydrogen Peroxide

Organic electronics have garnered important attention, as they offer alternatives to classic, more expensive electronic materials and great biocompatibility for building (bio)-chemical sensors. Among them, organic electrochemical transistors (OECTs) provide in situ signal amplification, which translates to excellent performance in electrochemical (bio)-sensing. This work presents a compact paper-based thick-film quasi-solid-state OECT (QSS-OECT) that integrates the gate and channel in a vertically stacked design. Electrochemical activation by pulsing the gate voltage allows reaching high transconductances of up to 12.4 mS. This system is applied to the detection of H₂O₂ with a sensitivity of 3.5 ± 0.3 mA/dec. The compact vertical configuration of the device allows for a drastic sample volume reduction, which can be performed with droplets of 1 μL as well as under the flow regime with an open cell configuration. The versatility and high transconductance of this device open new avenues for integration within low-cost sensors and biowearable platforms.