Nanofluidic Memristor Based on the Ionic Liquid-Electrolyte Solution Interface at the Conical Nanopore

In biological neural systems, learning and memory rely on ion transport in liquid environments. Owing to their biomimetic signaling mechanisms, nanofluidic memristors with tunable conductance can emulate synaptic memory and plasticity, having attracted significant attention. In this work, we propose a nanofluidic memristor based on the ionic liquid-electrolyte solution interface at a conical quartz nanopipette. By exploitation of the geometric asymmetry of the conical nanopore and the dynamic deformation of the interface between two immiscible liquids, the device exhibits significant current hysteresis and conductance memory effects. The feasibility was first evaluated by finite-element simulations and then confirmed through experiment. The influence of key parameters on device performance, including pore diameter, electrolyte concentration, and voltage scanning rate, was systematically investigated. Under sustained pulsed voltage stimulation, the device exhibits synaptic-like long-term potentiation (LTP) and long-term depression (LTD). Notably, these processes display asymmetric time scales under forward and reverse voltage biases. This behavior closely emulates the characteristic rapid potentiation and slow decay of synaptic weights observed in biological synapses. The study provides a simple, highly tunable, and biocompatible nanofluidic platform, paving the way for the development of advanced neuromorphic devices.