Flexible Ag nanowires/WO3-x/Au artificial synapses for wearable electrocardiogram recognition

A flexible Ag NWs/WO 3- x /Au memristor is successfully fabricated. • The device achieves an ultra-low energy consumption of 3.89 fJ per pulse. • The device achieves a competitive ECG recognition accuracy of 94.3%. • The device exhibits robust mechanical flexibility. The simultaneous achievement of high mechanical flexibility, ultra-low energy consumption, and high recognition accuracy remains a major challenge for wearable intelligent devices. Here, we report a flexible memristive device capable of emulating biological synaptic functions, fabricated with a spin-coated flexible Ag nanowire (NW) bottom electrode, an electrodeposited conformal WO 3- x coating as the functional layer, and an evaporation-defined Au top electrode. With a stacked Ag NWs/WO 3- x /Au architecture and strong interfacial bonding from the conformal coating, the device exhibits robust mechanical flexibility and cycling stability. Notably, the device achieves an ultra-low average energy consumption of merely 3.89 fJ per spike, attributed to the electrodeposition process that generates abundant short-range continuous oxygen vacancies, which shorten the ion migration path and lower the diffusion barrier, thereby enabling conductive filament formation at low voltages. When applied to electrocardiogram (ECG) signal recognition, the device achieves an accuracy of 94.3%, with negligible performance degradation after 2000 bending cycles, underscoring its robust flexibility. These advantages position this memristor as a promising building block for wearable ECG monitoring systems. Download: Download high-res image (221KB) Download: Download full-size image