Mechanistic Insights into Synaptic Plasticity Behaviors of Electrolyte-Gated Flexible Transistor Devices

Biological synaptic function simulationusing flexibleelectronicdevices based on low-dimensional semiconductor materials is an emergingand rapidly evolving research field with promising applications inbrain-like computers and artificial intelligence systems. In thiswork, we present the fabrication of solution compatible MoS2 thin-film transistors on the ultrathin polymethyl methacrylate substratesvia layer-by-layer assembly followed by a one-step transfer printingmethod. The MoS2 transport channel is controlled by ionicliquid gating with 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide,resulting in excellent synaptic performances for emulating memoryand perception synapse functions. To investigate the synaptic behaviors,we conduct a series of synaptic spike-dependent experiments and proposean advanced model that delineates the long-term plasticity and short-termplasticity with separate characteristic factors. These findings provideinsights into the fundamental mechanisms of synaptic plasticity inelectric double-layer devices and contribute to a better understandingof their synaptic performances. In addition, we examine the effectsof bending conditions on synaptic plasticity and synaptic weights,unveiling the synergistic interplay between mechanical deformationand synaptic behaviors. Our experimental results, combined with thedeveloped model, are in good agreement and shed light on the influenceof mechanical flexibility on the synaptic properties of the devices.In summary, this study establishes a solid foundation for furtherdevelopment of flexible synaptic devices from both practical and theoreticalperspectives.