From faceted nanoparticles to nanostructured thin film by plasma-jet redox reaction of ionic gold

Cold-atmospheric plasma-assisted deposition has emerged as an efficient technique for synthesising gold nanoparticles (AuNPs). Here, a plasma-vapour interaction is used for the simultaneous reduction and de-position of AuNPs from an inorganic precursor (HAuCl4). As surface analyses suggest, plasma input power plays an important role in reduction efficiency, whereas argon gas flow rate reduction leads to the for-mation of smaller particles. This study demonstrates that the presence of ethanol in the reactive mixture of gold promotes improved reduction of gold to nanostructures owing to their volatile properties. A systematic investigation of plasma and the deposited nanostructures reveals that the reduction is mainly caused by the free electrons and in-situ formation of hydrogen peroxide inside plasma. Our method demonstrates that nanostructured thin film can be created within 5 min by controlling plasma parameters. Deposited AuNPs feature advanced plasmonic surface-enhanced Raman scattering responses, tested with Raman marker Rhodamine R6G, enabling their use as a potential substrate for fast and reliable optical analytical bio-chemical sensing.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Cold-atmospheric plasma-assisted deposition is an efficient technique for synthesizing gold nanoparticles, and the presence of ethanol promotes the reduction of gold to nanostructures. Nanostructured thin films can be created within a short time by controlling plasma parameters. The deposited gold nanoparticles exhibit advanced plasmonic surface-enhanced Raman scattering responses, making them potential substrates for fast and reliable optical analytical bio-chemical sensing.