Engineering Electrostatic Repulsion of Metal Nanoparticles for Reduced Adsorption in Single-Impact Electrochemical Recordings

Lennart J.K. Weiß, Emir Music, Philipp Rinklin, Lea Straumann, Leroy Grob, Dirk Mayer, Bernhard Wolfrum

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Stochastic impact electrochemistry is a promising concept to detect ultralow concentrations of nanoparticles in solution. However, statistically reliable sensor outputs require an appropriate number of observed nanoparticle collision events. Here, arrays of individually addressable electrodes allow increasing the effective detection area, and thereby the number of collision events, without sacrificing the signal-to-noise ratio. At the same time, however, these measurements typically increase the surface-to-volume ratio of the system, leading to a stronger influence of adsorption on the number of available particles. We address this issue of nanoparticle adsorption by controlling the electrode-electrolyte interface close to the detection electrodes. We use a direct nanoimpact experiment to demonstrate that a negatively charged surface leads to electrostatic repulsion, which results in a 2.5-fold increase in the number of detected collision events. Adding to this improved sensor performance, a tunable shield electrode offers a versatile tool to study nanoparticle adsorption at the solid-liquid interface.

Original languageEnglish
Pages (from-to)8314-8320
Number of pages7
JournalACS Applied Nano Materials
Volume4
Issue number8
DOIs
StatePublished - 27 Aug 2021

Keywords

  • adsorption
  • digital sensors
  • direct nanoimpact method
  • electrostatic repulsion
  • silver nanoparticles
  • stochastic single-entity electrochemistry

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