A model for the current-voltage characteristic of membrane/electrolyte junctions

TL;DR

This paper develops a model for the current-voltage behavior of membrane/electrolyte junctions, comparing it with numerical simulations, and finds similarities to semiconductor junctions with a specific non-ideality factor.

Contribution

It introduces a novel analytical model for membrane/electrolyte junctions that aligns with Poisson-Nernst-Planck simulations and highlights the role of ion re-arrangement.

Findings

Model resembles semiconductor pn junction behavior

Non-ideality factor of 2 linked to ion re-arrangement

Good agreement with numerical simulations

Abstract

A model for the current-voltage characteristic of the junction between an Ion-Sensitive-Membrane and an electrolyte solution is derived and compared with numerical simulations of the Poisson-Nernst-Planck model for ion transport. The expression resembles that of a semiconductor pn junction with a non-ideality factor of 2. The non-ideality correlated to the voltage drop in the electrolyte induced by the re-arrangement of the counter-ions.