Electrostatically Gated Trilayer Graphene Nanopore as an Ultrathin Rectifying Ion Filter

Area of Science:

• Materials Science
• Nanotechnology
• Biophysics

Background:

• Biological ion channels possess remarkable selectivity and rectification properties crucial for cellular functions.
• Developing artificial analogs with similar capabilities remains a significant challenge in nanotechnology.
• Two-dimensional (2D) materials offer promising platforms for creating advanced nanopore-based devices.

Purpose of the Study:

• To engineer a subnanometer trilayer graphene (TLG) nanopore with a conical structure.
• To investigate its potential as a switchable biomimetic ion filter.
• To explore the effects of electrostatic gating on ion transport properties.

Main Methods:

• Fabrication of a subnanometer trilayer graphene (TLG) nanopore with a conical geometry.
• Experimental characterization of ion selectivity and current-voltage (I-V) behavior.
• Application of electrostatic gating to modulate nanopore conductance.
• Theoretical modeling of ion transport mechanisms and electrical double layer (EDL) interactions.

Main Results:

• The TLG nanopore demonstrated high ion selectivity and inherent rectification.
• Electrostatic gating significantly amplified the rectification ratio to ultrahigh values.
• Transmembrane voltage induced reversible "on" and "off" conductance states, mimicking action potentials.
• Theoretical analysis attributed unique transport to contrasting EDL overlaps and internal electric fields.

Conclusions:

• The developed TLG nanopore functions as an effective switchable biomimetic ion filter.
• The study highlights the potential of electrostatic gating for controlling ion transport in 2D materials.
• This work paves the way for ultrathin in vitro biomimetic devices for energy conversion and biosensing.