Long-ionic-gated graphene synaptic transistor with enhanced memory, learning function and humidity perception.

This article focuses on the development and investigation of an ionic-gated graphene synaptic transistor with a long-gate structure designed to mimic biological synaptic functions such as memory, learning, and humidity perception. The device exploits ion migration and charge carrier transport in graphene and ion-gel to reproduce synaptic behaviors including inhibitory and excitatory postsynaptic currents, paired-pulse facilitation (PPF), long-term potentiation (LTP), and long-term depression (LTD), with enhanced PPF reaching approximately 265%. Additionally, the transistor demonstrates sensitivity to ambient humidity between 30% and 75% relative humidity, affecting its synaptic responses due to interactions of water molecules with ions and graphene. The study highlights the transistor's ability to replicate Ebbinghaus' memory curve through repetitive learning and forgetting cycles, suggesting its potential for integrated neuromorphic systems combining sensing, storage, and computation.