Electrostatic\nModulation for Enhanced Ion Selectivity\nin Gate-All-Around Multilayer Stacked Graphene Nanopore

Biological ion channels exhibit exceptional\ngating capabilities\nfor regulated transport and filtration across cell membranes. This\nstudy explores similar gating functions in artificial nanopores using\ngraphene membranes. By applying direct voltage, we can dynamically\ncontrol ion distribution around nanopores, allowing for real-time\ntriggering, dynamic flow control, and adaptability to varying pore\nsizes. We investigate electrostatic modulation of ion transport in\na stacked nanoporous graphene configuration, which mitigates defects\nfrom growth and transfer processes. Nanopores are created using oxygen\nplasma, enabling fine-tuning of ion transport. External voltage enhances\nion conductivity at positive voltages and reduces it at negative voltages,\ndemonstrating significant modulation by the surface potential-induced\nelectric double layer (EDL). Voltage-dependent ion enrichment and\ndepletion within the nanopores affect the effective surface charge\ndensity, facilitating controllable ion sieving. Results show that\nnanopores, with sizes comparable to hydrated ion diameters, achieve\nhigh and tunable voltage-gating functionality, enabling efficient\non-demand ion transport. Voltage-gating effectively tunes ion selectivity\nin multilayer stacked graphene membranes, with negative voltages impeding\ndivalent cations and positive voltages mimicking biological K<sup>+</sup> nanochannels. This research lays the foundation for developing\nnanopores with tunable ion selectivity for applications in energy\nconversion, ion separation, and nanofluidics.