Effects of a Flexible Ion Gel as an Active Outer-Layer when in Contact with a Metallic Electrode

TL;DR

This study investigates how a flexible ion gel outer-layer affects the electrical properties of ITO/PBT/Sn devices, revealing reversible modulation of charge injection and current density through interfacial effects.

Contribution

It demonstrates that external ion gel layers can actively modify device electrical behavior without diffusion into the active layer, offering new ways to enhance device performance.

Findings

Current can increase up to two orders of magnitude with the gel layer.

Current can decrease by one order of magnitude with the gel layer.

Changes are reversible after removing the ion gel, indicating no diffusion.

Abstract

In this work the effect of an ion gel outer-layer stuck on top of ITO/PBT/Sn devices was investigated towards its effects on the electrical properties. When this external electrolyte film is in contact with any top permeable electrode it produces a self-biasing effect and changes the charge carriers injection properties. The outer-layer promoted situations where the output current increases up to two orders of magnitude and others where the output current decreases one order of magnitude in comparison to the same samples without it. Admittance spectroscopy measurements were made and the proposed equivalent circuit model indicates that the interfacial electrical properties dominate charge injection face to the bulk properties when the outer-layer is present. All the changes observed here are reversible after the ion gel is detached and replaced, indicating that ions do not diffuse into the active layer. The observed results can contribute to improve the current density in certain sandwich structures as well as notify that electrolyte external films can behave as an active layer promoting electrical changes into sandwich devices and can be extended to cases where the electrolyte film is used as substrate.