Photopatternable Gel Electrolytes for Stretchable Solid-State Organic Electrochemical Transistors
Organic electrochemical transistors (OECTs) offer high transconductance and biocompatibility for wearable biosensing, yet their deployment in conformal, long-term electrophysiological monitoring is constrained by the mechanical mismatch and leakage of liquid electrolytes. This work introduces a double-network stretchable gel electrolyte that simultaneously achieves a Young’s modulus of 114 kPa and an elongation at break of 640%, matching soft biological tissues while enabling photopatterning for high-density device arrays. Integrating this electrolyte with a stretchable PEDOT:PSS channel yields solid-state OECTs with a volumetric capacitance–mobility product ([μC*]) of 317.71 ± 11.61 F cm⁻¹ V⁻¹ s⁻¹ and an average transconductance of 7.89 mS across uniform arrays. Under 50% tensile strain, the devices maintain stable electrical performance and acquire electrocardiogram signals with a signal-to-noise ratio of approximately 30 dB. The fabrication route is low-cost and compatible with solution processing, addressing the trade-off between ionic conductivity and mechanical robustness that has hindered previous gel electrolytes. These results demonstrate a viable pathway for stretchable, solid-state OECTs in ambulatory cardiac monitoring and high-resolution biointerfaces, where mechanical compliance and signal fidelity are paramount.