Electric-Double-Layer-Modulation Microscopy

Kevin Namink, Xuanhui Meng, Marc T.M. Koper, Philipp Kukura, Sanli Faez

Research output: Contribution to journalArticleAcademicpeer-review


The electric double layer (EDL) formed around charged nanostructures at the liquid-solid interface determines their electrochemical activity and influences their electrical and optical polarizability. We experimentally demonstrate that restructuring of the EDL at the nanoscale can be detected by dark-field scattering microscopy. Temporal and spatial characterization of the scattering signal demonstrates that the potentiodynamic optical contrast is proportional to the accumulated charge of polarizable ions at the interface and that its time derivative represents the nanoscale ionic current. The material specificity of the EDL formation is used in our work as a label-free contrast mechanism to image nanostructures and perform spatially resolved cyclic voltammetry on an ion-current density of a few attoamperes, corresponding to the exchange of only a few hundred ions.

Original languageEnglish
Article number044065
JournalPhysical Review Applied
Issue number4
Publication statusPublished - 1 Apr 2020


  • Electrochemistry
  • Electrostatic double layer forces
  • Metrology


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