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Title: Polarization of gold in nanopores leads to ion current rectification

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 ionmore » current rectification even in low-aspect ratio nanopores. Lastly, our findings enable a new strategy for creating ionic circuits with diodes and transistors.« less
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [1]
  1. Univ. of California, Irvine, CA (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 7; Journal Issue: 20; Journal ID: ISSN 1948-7185
Publisher:
American Chemical Society
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Laboratory Directed Research and Development (LDRD) Program
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1344289

Yang, Crystal, Hinkle, Preston, Menestrina, Justin, Vlassiouk, Ivan V., and Siwy, Zuzanna S.. Polarization of gold in nanopores leads to ion current rectification. United States: N. p., Web. doi:10.1021/acs.jpclett.6b01971.
Yang, Crystal, Hinkle, Preston, Menestrina, Justin, Vlassiouk, Ivan V., & Siwy, Zuzanna S.. Polarization of gold in nanopores leads to ion current rectification. United States. doi:10.1021/acs.jpclett.6b01971.
Yang, Crystal, Hinkle, Preston, Menestrina, Justin, Vlassiouk, Ivan V., and Siwy, Zuzanna S.. 2016. "Polarization of gold in nanopores leads to ion current rectification". United States. doi:10.1021/acs.jpclett.6b01971. https://www.osti.gov/servlets/purl/1344289.
@article{osti_1344289,
title = {Polarization of gold in nanopores leads to ion current rectification},
author = {Yang, Crystal and Hinkle, Preston and Menestrina, Justin and Vlassiouk, Ivan V. and Siwy, Zuzanna S.},
abstractNote = {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.},
doi = {10.1021/acs.jpclett.6b01971},
journal = {Journal of Physical Chemistry Letters},
number = 20,
volume = 7,
place = {United States},
year = {2016},
month = {10}
}