Stretchable and low-voltage electrolyte gate organic thin film transistors based on ionic gel for glucose sensing

Stretchable extended-gate organic thin film transistor (OTFT) not only retains the high selectivity inherent to electrochemical sensing but also integrates the intrinsic flexibility and in situ signal amplification capabilities of stretchable organic thin film transistors. This design significantly reduces the signal processing burden at the backend, enhances signal sensitivity, and extends the detection limit, demonstrating great potential for wearable sweat sensors. However, the widespread adoption of stretchable OTFT in wearable electronics has been hindered by their high operating voltages and limited operational stability. Here, a stretchable ionic gel was proposed as the dielectric layer, enabling the fabrication of intrinsically stretchable electrolyte gate organic thin film transistor (EGOTFT) with ultralow operating voltages (<1 V). The resulting devices exhibited a remarkably low operating voltage of −0.5 V, excellent long-term stability (over 30 days), and a steep subthreshold slope of 98 mV dec⁻¹. Meanwhile, the stretchable EGOTFT demonstrated high mechanical durability, maintaining stable electrical performance under 40% strain and after 10⁴ stretching-releasing cycles. Based on this EGOTFT architecture, a wearable glucose sensor was realized, meeting the safety and conformability requirements for wearable biomedical applications. This work opens a new opportunity for e-skin with signal-identification capabilities.