Spontaneous adsorption of ions on graphene at the electrolyte–graphene interface

Jianbo Sun, Luca Camilli, José M. Caridad, Jaime E. Santos, Yuxin Liu*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We report the spontaneous adsorption of ions on graphene at the interface with electrolytes through an investigation based on the electrolyte-gated field effect transistor configuration. It is found that the gate voltage at which the minimum conductivity occurs in these devices is highly sensitive to the type of ions and their concentrations in the electrolytes; yet the experimental results exhibit non-trivial deviations from the predictions based on the Gouy–Chapman–Stern (GCS) model, which only takes account of the electrostatic interactions among the charges in the system. By incorporating a Langmuir-type adsorption term into the GCS model, we achieve quantitative alignment with the experiments, thus demonstrating that these deviations originate from the spontaneous adsorption of ions onto graphene. Analysis of the transport characteristics in these devices indeed confirms the existence of the adsorbed ions.
Original languageEnglish
Article number203102
JournalApplied Physics Letters
Volume117
Issue number20
Number of pages7
ISSN0003-6951
DOIs
Publication statusPublished - 2020

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