The Drift Diffusion Simulation of Coupled Ionic -Electronic Devices

This thesis creates a numerical simulation scheme for a coupled ionic electronic device and uses it to simulate a memristor based on an or- ganic conductor called poly(3,4 ethylenedioxythiophene):polystyrene- sulfonate (PEDOT:PSS). The modeled memristor consists of a thin PEDOT:PSS strip with a metal contact on both sides and a drop of an electrolyte solution with lithium and perchlorate ions. The conductivity of the memristor changes when the lithium ions in the electrolyte dedopes the PEDOT:PSS by bonding with PSS polymers. A numerical drift diffusion and a Poisson solver was implemented with special features to model the physical properties of the memris- tor. The developed simulation algorithm was tested using analytical solutions to the drift diffusion equations and Poisson's equation. 1- D and 2-D simulations were able to capture the essential physical effects.