Vapour sensing properties of graphene-covered gold nanoparticles

TL;DR

This study explores how graphene-covered gold nanoparticles can be used as vapour sensors, showing that their optical properties change with different vapours and that graphene enhances sensitivity to certain alcohols.

Contribution

It demonstrates the tunability of optical responses in graphene-gold nanostructures and highlights the influence of nanoparticle shape and graphene overlay on vapour sensitivity.

Findings

Smaller gold nanoparticles are more sensitive to vapours.

Graphene increases sensitivity to ethanol and 2-propanol.

Sensitivity to toluene decreases with graphene coverage.

Abstract

We investigated the vapour sensing properties of different graphene-gold hybrid nanostructures. We observed the shifts in the optical spectra near the local surface plasmon resonance of the gold nanoparticles by changing the concentration and nature of the analytes (ethanol, 2-propanol, and toluene). The smaller, dome-like gold nanoparticles proved to be more sensitive to these vapours compared to slightly larger, flat nanoparticles. We investigated how the optical response of the gold nanoparticles can be tuned with a corrugated graphene overlayer. We showed that the presence of graphene increased the sensitivity to ethanol and 2-propanol, while it decreased it towards toluene exposure (at concentrations higher than 30%). The slope changes observed on the optical response curves were discussed in the framework of capillary condensation. These results can have potential impact on the development of new sensors based on graphene-gold hybrids.