Journal Article

SERS Hotspot Engineering by Aerosol Self‐Assembly of Plasmonic Ag Nanoaggregates with Tunable Interparticle Distance

Thersleff, Thomas, Sommertune, Jens, Li, Haipeng, Merkl, Padryk, Sotiriou, Georgios A.

2022

Overview

Surface‐enhanced Raman scattering (SERS) is a powerful sensing technique. However, the employment of SERS sensors in practical applications is hindered by high fabrication costs from processes with limited scalability, poor batch‐to‐batch reproducibility, substrate stability, and uniformity. Here, highly scalable and reproducible flame aerosol technology is employed to rapidly self‐assemble uniform SERS sensing films. Plasmonic Ag nanoparticles are deposited on substrates as nanoaggregates with fine control of their interparticle distance. The interparticle distance is tuned by adding a dielectric spacer during nanoparticle synthesis that separates the individual Ag nanoparticles within each nanoaggregate. The dielectric spacer thickness dictates the plasmonic coupling extinction of the deposited nanoaggregates and finely tunes the Raman hotspots. By systematically studying the optical and morphological properties of the developed SERS surfaces, structure–performance relationships are established and the optimal hot‐spots occur for interparticle distance of 1 to 1.5 nm among the individual Ag nanoparticles, as also validated by computational modeling, are identified for the highest signal enhancement of a molecular Raman reporter. Finally, the superior stability and batch‐to‐batch reproducibility of the developed SERS sensors are demonstrated and their potential with a proof‐of‐concept practical application in food‐safety diagnostics for pesticide detection on fruit surfaces is explored. Robust surface‐enhanced Raman scattering (SERS) sensing surfaces are fabricated using one‐step flame nanoparticle deposition. The sensing surfaces exhibit superior stability and high batch‐to‐batch reproducibility, highlighting their potential in practical (bio)chemical sensing. The detection of pesticides on fruit surfaces demonstrates a proof‐of‐concept practical application in food safety diagnostics at the point of consumption.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc
• Subject: Aerosols / Electromagnetism / Enhanced Raman scattering / Fabrication / flame aerosol deposition / Flame aerosol depositions / Fractals / Glass substrates / Metal nanoparticles / Metal Nanoparticles - chemistry / Morphology / Nanoparticles / Nanostructured materials / Particle size / pesticide residue detection / Pesticides / Pesticides residue detection / Plasmonic nanoparticle / plasmonic nanoparticles / Plasmonics / Raman scattering / Raman scattering substrate / Reproducibility of Results / Self assembly / SERS substrate fabrication / Silver - chemistry / Silver nanoparticles / Spectrum analysis / Spectrum Analysis, Raman - methods / Substrates / Surface enhanced Raman / Surface scattering / Surface-enhanced raman scattering / Surface-enhanced raman scattering substrate fabrication / surface‐enhanced Raman scattering (SERS) / Synthesis (chemical) / Transmission electron microscopy