Intrinsically Stretchable Vertical Organic Electrochemical Transistor Featuring Sub-Nanometer-Roughness Electrodes for High Transconductance and Stretchability

Stretchable organic electrochemical transistors (S-OECTs) are known for their high transconductance, low operating voltage, and excellent mechanical compliance. Despite advancements in molecular design and geometric engineering, achieving both high transconductance and stable performance under a large strain remains a challenge. This study demonstrates high-transconductance intrinsically stretchable vertical OECTs, fabricated via a smooth stretchable bilayer electrode and a stretchable organic semiconductor. The combination of a smooth evaporated Au layer and transfer printing of Ag NWs endows the electrode with sub-nanometer surface roughness and high conductivity under stretching, ensuring the devices with both high transconductance (∼55 mS) and stretchability (100%). Under 100% strain, the devices successfully demonstrate rich synaptic functionalities and achieve a remarkably high paired-pulse facilitation (PPF) index of 319.82%. When configured into a reservoir computing network, the system achieves 91.76% accuracy in handwritten digit recognition under 100% strain, showcasing significant potential for wearable neuromorphic electronics applications.