Laser-patterned Thin-film Electrodes: Imaging Ion Accumulation and Trapped Nanoparticles

TL;DR

This paper presents a novel laser-fabricated electrode design with sharp nanostructures that enables simultaneous imaging of ion accumulation and nanoparticle trapping, advancing electrochemical and colloidal research.

Contribution

Introduces a simple, laser-ablated electrode with sharp tips for dual observation of ion and nanoparticle behavior under electrical potentials.

Findings

Effective ion accumulation imaging via total-internal reflection microscopy.

Successful nanoparticle trapping under high-frequency alternating potentials.

Electrode fabrication method enables easy nanostructure creation.

Abstract

This study introduces a straightforward electrode design featuring sharp edges with a curvature of a few hundred nanometers in radius, with which both ion accumulation and nanoparticle deposition can be observed under an alternating electrical potential. The electrodes, termed 'shark-teeth electrodes', are fabricated using a laser ablation technique optimized for facile nanostructure creation. This method involves successive, overlapping ablated discs in a thin film of gold, producing sharp tips that generate strong electric fields. When electrically polarized in an electrolyte solution, these sharp tips form a screening layer, facilitating the observation of ion and nanoparticle behavior. A total-internal reflection microscope is employed to monitor ion accumulation on these electrodes, demonstrating their capability in iontronic microscopy. Additionally, the same electrodes are used to track nanoparticle trapping under high-frequency alternating potentials. This dual functionality allows for the investigation of electrochemical and physical interactions between ions and colloidal nanoparticles, contributing valuable insights to the field of soft matter.