Gate Metal-Driven Sensing and Memory Bifunctionality in Intrinsically Stretchable Organic Electrochemical Transistors for Soft Neuromorphic Systems.

Intrinsically stretchable devices capable of integrating sensing, memory and signal processing are highly desirable for conformal bioelectronics. However, achieving such multifunctionality remains challenging due to conflicting operational requirements and the lack of mechanically compliant electrochemical gating strategies that preserve functional operation under deformation. Here, we present optimal materials and device strategies for intrinsically stretchable organic electrochemical transistors (OECTs) that enable gate metal-driven bifunctionality within a single integrated platform. The device is constructed using a phase-separated elastic semiconductor coupled with an ionically conductive alginate hydrogel, together with two stretchable gate electrodes: (1) Ag/AgCl for transient electrochemical responses; and (2) Au for persistent conductance modulation. By selectively addressing these gate electrodes, the OECT supports both fast, reversible responses for transient signal detection using bio-inspired input waveforms, while also enabling stable conductance modulation for synapse-like memory behavior, which is further utilized to implement artificial neural network (ANN)-based pattern recognition using experimentally extracted conductance states. Furthermore, the bifunctional operation enables associative learning behavior in which repeated paired inputs progressively strengthen the device response, leading to successful threshold-based decision making even under deformation up to 30% strain. Our work establishes an efficient methodology for achieving soft brain-inspired OECT platforms that integrate sensing, memory and neuromorphic functionality.