Detection and Characterization of Single Particles by Electrochemical Impedance Spectroscopy

Brian Roehrich, Eric Z. Liu, Ravit Silverstein, Lior Sepunaru

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


We present an electrochemical impedance spectroscopy (EIS) technique that can detect and characterize single particles as they collide with an electrode in solution. This extension of single-particle electrochemistry offers more information than typical amperometric single-entity measurements, as EIS can isolate concurrent capacitive, resistive, and diffusional processes on the basis of their time scales. Using a simple model system, we show that time-resolved EIS can detect individual polystyrene particles that stochastically collide with an electrode. Discrete changes are observed in various equivalent circuit elements, corresponding to the physical properties of the single particles. The advantages of EIS are leveraged to separate kinetic and diffusional processes, enabling enhanced precision in measurements of the size of the particles. In a broader context, the frequency analysis and single-object resolution afforded by this technique can provide valuable insights into single pseudocapacitive microparticles, electrocatalysts, and other energy-relevant materials.

Original languageEnglish
Pages (from-to)9748-9753
Number of pages6
JournalJournal of Physical Chemistry Letters
Issue number40
StatePublished - 14 Oct 2021
Externally publishedYes

ASJC Scopus subject areas

  • General Materials Science
  • Physical and Theoretical Chemistry


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