Infrared Nanospectroscopy at the Graphene–Electrolyte Interface

Infrared Nanospectroscopy at the Graphene–Electrolyte Interface

TitleInfrared Nanospectroscopy at the Graphene–Electrolyte Interface
Publication TypeJournal Article
Year of Publication2019
AuthorsYi-Hsien Lu, Jonathan M Larson, Artem Baskin, Xiao Zhao, Paul D Ashby, David G Prendergast, Hans A Bechtel, Robert Kostecki, Miquel Salmeron
JournalNano Letters
Volume19
Issue8
Pagination5388 - 5393
Date Published07/2019
ISSN1530-6984
Abstract

We present a new methodology that enables studies of the molecular structure of graphene–liquid interfaces with nanoscale spatial resolution. It is based on Fourier transform infrared nanospectroscopy (nano-FTIR), where the infrared (IR) field is plasmonically enhanced near the tip apex of an atomic force microscope (AFM). The graphene seals a liquid electrolyte reservoir while acting also as a working electrode. The photon transparency of graphene enables IR spectroscopy studies of its interface with liquids, including water, propylene carbonate, and aqueous ammonium sulfate electrolyte solutions. We illustrate the method by comparing IR spectra obtained by nano-FTIR and attenuated total reflection (which has a detection depth of a few microns) demonstrating that the nano-FTIR method makes it possible to determine changes in speciation and ion concentration in the electric double and diffuse layers as a function of bias.

DOI10.1021/acs.nanolett.9b01897
Short TitleNano Lett.
Refereed DesignationRefereed