Polarization of gold in nanopores leads to ion current rectification
Journal Article
·
· Journal of Physical Chemistry Letters
- Univ. of California, Irvine, CA (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Biomimetic nanopores with rectifying properties are relevant components of ionic switches, ionic circuits, and biological sensors. Rectification indicates that currents for voltages of one polarity are higher than currents for voltages of the opposite polarity. Ion current rectification requires the presence of surface charges on the pore walls, achieved either by the attachment of charged groups or in multielectrode systems by applying voltage to integrated gate electrodes. Here we present a simpler concept for introducing surface charges via polarization of a thin layer of Au present at one entrance of a silicon nitride nanopore. In an electric field applied by two electrodes placed in bulk solution on both sides of the membrane, the Au layer polarizes such that excess positive charge locally concentrates at one end and negative charge concentrates at the other end. Consequently, a junction is formed between zones with enhanced anion and cation concentrations in the solution adjacent to the Au layer. This bipolar double layer together with enhanced cation concentration in a negatively charged silicon nitride nanopore leads to voltage-controlled surface-charge patterns and ion current rectification. The experimental findings are supported by numerical modeling that confirm modulation of ionic concentrations by the Au layer and ion current rectification even in low-aspect ratio nanopores. Lastly, our findings enable a new strategy for creating ionic circuits with diodes and transistors.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- ORNL LDRD Director's R&D; USDOE
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1344289
- Journal Information:
- Journal of Physical Chemistry Letters, Journal Name: Journal of Physical Chemistry Letters Journal Issue: 20 Vol. 7; ISSN 1948-7185
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Current rectification for transport of room-temperature ionic liquids through conical nanopores
Ion concentration polarization causes a nearly pore-length-independent conductance of nanopores
Journal Article
·
Mon Feb 08 19:00:00 EST 2016
· Journal of Physical Chemistry. C
·
OSTI ID:1339300
Ion concentration polarization causes a nearly pore-length-independent conductance of nanopores
Journal Article
·
Wed Aug 07 20:00:00 EDT 2024
· Faraday Discussions
·
OSTI ID:3002051