Ionic species programmable synaptic plasticity in multimodal nanofluidic devices

Nanofluidic devices have been widely utilized to simulate electronic functionalities recently, due to their unique ion transport behaviors, such as non-linear ion transport, selectivity etc. However, the correlation between the ion transport behavior and the transitions among various nanofluidic capacitive and inductive hysteresis still remains poorly understood, which impedes the development of nanofluidic systems. Here, we report a concentration-dependent transition between capacitive and inductive hysteresis in gold-nanoparticle-stacked nanochannels. Quantitative analysis reveals that this transition is governed by the interionic distance relative to the Bjerrum length, establishing a universal mechanism for ion transport modulation. Notably, our system enables unidirectional plasticity (both facilitation and depression) by simply altering the ionic species, demonstrating programmable plasticity without structural reconfiguration. Additionally, a high-pass filter (HPF) circuit with tunable cut-off frequency is implemented through two identical nanofluidic devices. These findings establish a new paradigm for multifunctional nanofluidic devices and provide a rational foundation for the design of aqueous-phase neuromorphic computing circuits.