Taking the Plunge: Nanoscale Chemical Imaging of Functionalized Gold Triangles in H2O via TERS

TL;DR

This paper demonstrates rapid nanoscale chemical imaging in water using tip-enhanced Raman scattering (TERS) on functionalized gold triangles, achieving sub-15 nm resolution and mapping local optical fields at solid-liquid interfaces.

Contribution

The study introduces a fast, high-resolution TERS imaging platform in aqueous environments, enabling direct mapping of local optical fields on plasmonic nanostructures.

Findings

Achieved 0.25 s/pixel imaging speed.

Sub-15 nm spatial resolution in water.

Mapped local optical fields at edges and corners of gold triangles.

Abstract

We demonstrate fast (0.25 s/pixel) nanoscale chemical imaging in aqueous solution via tip-enhanced Raman scattering (TERS), with sub-15 nm spatial resolution. The substrate consists of 4-mercaptobenzonitrile-functionalized monocrystalline gold triangular platelets immersed in H2O, which we map using a gold-coated AFM probe illuminated using a 633 nm laser source. We find that the recorded TERS images trace the enhanced local optical fields that are sustained towards the edges and corners of the triangles. In effect, we directly map local optical fields of a plasmonic substrate in aqueous solution through molecular TERS. Overall, our described platform and approach may generally be used for chemical and biological imaging, and potentially, to follow chemical transformations at solid-liquid interfaces through TERS.