Issue 41, 2019

Vogel–Tammann–Fulcher model for charging dynamics in an organic electrochemical transistor

Abstract

The mechanisms which underlie the dynamic behavior of organic electrochemical transistors are investigated with a series of in situ infrared spectroscopic measurements on metal–electrolyte–semiconductor capacitors. By varying the device geometry, we are able to separate the fundamental processes that determine transistor charging dynamics, namely, charge carrier mobility, ion conduction in the electrolyte, and mixed ion-carrier diffusion in the semiconductor. Surprisingly, charge carrier mobility has very little effect on the dynamics. Instead, either dielectric polarization or ion-carrier diffusion is the rate limiting step, depending on device geometry. The voltage dependence of the ion diffusion constant is determined, showing an exponential increase with the square of the applied voltage. Dynamics of several different ionic species are also measured. Paradoxically, faster transport is shown for larger anions. Temperature dependent measurements are also performed; ion diffusion shows an exponential slowing at lower temperature. The ion-carrier diffusivity can be understood with the Vogel–Tamman–Fulcher (VTF) equation whereby the activation energy is dependent on electrostatic energy density and the ionic solubility in the semiconductor. This model presents a generalizable framework to approach structure–property relationships for ion transport in organic semiconducting materials.

Graphical abstract: Vogel–Tammann–Fulcher model for charging dynamics in an organic electrochemical transistor

Supplementary files

Article information

Article type
Paper
Submitted
15 may 2019
Accepted
12 iyn 2019
First published
12 iyn 2019

J. Mater. Chem. C, 2019,7, 12935-12941

Vogel–Tammann–Fulcher model for charging dynamics in an organic electrochemical transistor

P. Shiri, E. J. S. Dacanay, B. Hagen and L. G. Kaake, J. Mater. Chem. C, 2019, 7, 12935 DOI: 10.1039/C9TC02563D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements