Stretchable and Low-Voltage Electrolyte Gate Organic Thin Film Transistors Based on Ionic Gel for Glucose Sensing
Stretchable extended-gate organic thin film transistors (OTFTs) combine the high selectivity of electrochemical sensing with the mechanical compliance and in situ signal amplification of organic electronics, offering a route to wearable sweat diagnostics. However, high operating voltages and limited operational stability have restricted their practical deployment. This work introduces a stretchable ionic gel as the dielectric layer, enabling an intrinsically stretchable electrolyte-gated organic thin film transistor (EGOTFT) that operates at ultralow voltages below 1 V. The device exhibits a low operating voltage of −0.5 V, a steep subthreshold slope of 98 mV dec−1, and stable performance over 30 days. Mechanical durability is maintained under 40% strain and after 10^4 stretching-releasing cycles. The EGOTFT is integrated with an extended-gate functionalized carbon nanotube electrode for glucose sensing. The sensor demonstrates a linear response from 100 μM to 1 mM with an R-squared value of 0.997, a limit of detection of 8.72 μM, and a limit of quantification of 29.08 μM. The platform combines low power consumption, high sensitivity, fast response, and good selectivity, meeting safety and conformability requirements for wearable biomedical applications. This work advances the development of electronic skin with signal-identification capabilities and provides a viable path toward continuous, non-invasive sweat glucose monitoring.