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Surface charge density governs the ionic current rectification direction in asymmetric graphene oxide channels
Shuang Li1, Xinke Zhang1, Jiaye Su1
1MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing, and Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, China. jysu@iccas.ac.cn.
Physical Chemistry Chemical Physics : PCCP
|February 28, 2023
Summary
Ionic current rectification in charged channels reverses direction with increasing surface charge density. This phenomenon, observed in graphene oxide channels, is due to electrostatic shielding at low densities and Coulomb blockade at high densities.
Area of Science:
- Nanofluidics
- Materials Science
- Physical Chemistry
Background:
- Charged asymmetric channels are key for artificial biological channels and ionic diodes.
- Surface charge density significantly impacts ionic current rectification.
Purpose of the Study:
- Investigate ionic current rectification in asymmetric graphene oxide channels.
- Understand the influence of surface charge density on rectification direction.
Main Methods:
- Molecular dynamics simulations were employed.
- Asymmetric graphene oxide channels were modeled.
Main Results:
- Ionic current rectification direction reversed with increasing surface charge density.
- Low charge density: enhanced ion transport in negative electric fields.
- High charge density: Coulomb blockade effect impedes ion transport in negative electric fields.
Conclusions:
- Surface charge density controls ionic current rectification direction in graphene oxide channels.
- Rectification reversion offers new design strategies for nanofluidic devices.
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