Electrostatic Modulation for Enhanced Ion Selectivity in Gate-All-Around Multilayer Stacked Graphene Nanopore

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Biological ion channels regulate transport across cell membranes.
• Artificial nanopores offer potential for controlled molecular transport.
• Graphene membranes provide a promising platform for nanopore fabrication.

Purpose of the Study:

• To explore voltage-gated ion transport in artificial nanopores.
• To investigate electrostatic modulation of ion flow in stacked graphene.
• To develop tunable ion selectivity in nanoporous membranes.

Main Methods:

• Fabrication of nanopores in graphene membranes using oxygen plasma.
• Application of direct voltage to modulate ion distribution and transport.
• Analysis of ion conductivity and selectivity in response to applied voltage.
• Investigation of the electric double layer (EDL) effect on ion transport.

Main Results:

• Dynamic control of ion distribution and flow via applied voltage.
• Significant voltage-dependent modulation of ion conductivity (enhancement at positive, reduction at negative voltages).
• Tunable ion selectivity achieved, mimicking biological K+ channels and impeding divalent cations.
• Demonstration of voltage-gating functionality in nanopores comparable to hydrated ion diameters.

Conclusions:

• Artificial nanopores exhibit tunable voltage-gating for on-demand ion transport.
• Electrostatic modulation via EDL is key to controlling ion transport and selectivity.
• Developed nanoporous graphene membranes offer potential for energy conversion, ion separation, and nanofluidics.