Reduced Graphene Oxide-Based Artificial Synapse Yarns for Wearable Textile Device Applications

A brain-inspired neuromorphic system is a promising computing concept that processes information at low power. Such systems can be applied to wearable devices in which low power consumption is important. Solid-state devices that have been used for neuromorphic device applications are not suitable for wearable applications that require high flexibility. Here, two-terminal memristor-based artificial synapses are proposed that are simply constructed by crossing two yarns coated with reduced graphene oxide (RGO) by electrochemical deposition. The artificial synapses mimic several important synaptic functions of biological synapses, including excitatory postsynaptic current, paired-pulse facilitation, and a transition from short-term plasticity to long-term plasticity. The artificial synapses can be operated stably without degradation during mechanical bending. By implementing a 2 x 2 cross-point array using RGO-coated yarns, the possibility of integrating artificial synapses for wearable neuromorphic systems is demonstrated. The yarn-based artificial synapses can be a key component of future neuromorphic wearable systems.