Open AccessControl of Selective Ion Transfer across Liquid–Liquid Interfaces: A Rectifying Heterojunction Based on Immiscible Electrolytes
Author(s) -
Guillermo Iván Guerrero-García,
Francisco J. Solis,
Kalyan Raidongia,
Andrew R. Koltonow,
Jiaxing Huang,
Mónica Olvera de la Cruz
Publication year - 2016
Publication title -
acs central science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.893
H-Index - 76
eISSN - 2374-7951
pISSN - 2374-7943
DOI - 10.1021/acscentsci.6b00266
Subject(s) - electric field , chemical physics , heterojunction , ion , electrolyte , ionic bonding , ionic liquid , solvation , materials science , chemistry , optoelectronics , physics , electrode , organic chemistry , quantum mechanics , catalysis
The current rectification displayed by solid-state p-n semiconductor diodes relies on the abundance of electrons and holes near the interface between the p-n junction. In analogy to this electronic device, we propose here the construction of a purely ionic liquid-state electric rectifying heterojunction displaying an excess of monovalent cations and anions near the interface between two immiscible solvents with different dielectric properties. This system does not need any physical membrane or material barrier to show preferential ion transfer but relies on the ionic solvation energy between the two immiscible solvents. We construct a simple device, based on an oil/water interface, displaying an asymmetric behavior of the electric current as a function of the polarity of an applied electric field. This device also exhibits a region of negative differential conductivity, analogous to that observed in brain and heart cells via voltage clamp techniques. Computer simulations and mean field theory calculations for a model of this system show that the application of an external electric field is able to control the bulk concentrations of the ionic species in the immiscible liquids in a manner that is asymmetric with respect to the polarity or direction of the applied electric field. These properties make possible to enhance or suppress selective ion transport at liquid-liquid interfaces with the application of an external electric field or electrostatic potential, mimicking the function of biological ion channels, thus creating opportunities for varied applications.