Carbon nanomaterials are of significant importance in the modern era of electronic devices, which revolutionised various fields, starting from electrodes and supercapacitors developments[1] toward high-performing functional sensors design.[2] Within the last decade, carbon-based nanostructures revealed a promising potential in a field of plasmonic SERS (surface-enhanced Raman scattering) sensing. The first reason behind the great success is attributed to the exceptional electronic properties that facilitate ultrafast charge transfer. The second is related to the affinity of carbon atoms to form different highly-stable 3D nanostructures such as nanowalls, nanoribbons, nanotubes, and a variety of other hybrid morphologies. These types of structures can be prepared by different synthesis approaches, where plasma-assisted methods are considered among the most efficient techniques. In a current research we employed plasma-enhanced chemical vapour deposition method to create multibranched forest-like carbon nanostructures on top of catalytic nickel surface via utilising low-pressure RF (radiofrequency) generated plasma and CH₄ as a gas precursor. Followed by a tip-growth mechanism, the designed substrates possessing a prominent surface morphology were decorated with plasmonic 100-nm gold layer aiming to form a dense network of hot spots regions. These surface-active sites enabled to generate strongly confined electric field under laser exposure that favors photon scattering processes at the metal/analyte interface. The improved optical response associated with a high analytical enhancement factor (AEF = 5 × 10⁷) allowed to use a gold-covered carbon nanoforest substrate to collect Raman fingerprints swiftly, with less than a minute, from toxic metabolites operating at the nanovolume sample quantities. The spectral data recorded from cereal associated cancerogenic aflatoxin B₁, alternariol, fumonisin B₁, and zearalenone were elaborated by principal component analysis statistical approach helping to distinguish hazardous species precisely and reliably, simultaneously involving minimal analytical efforts. The obtained findings pinpoint the excellent detection capabilities of the substrate optimised, confirming that plasma-assisted synthesis can be efficiently used for SERS chip development applied in agriculture and food inspection needs.

References

[1] Chen, Z., Ye, S., Evans, S. D., Ge, Y., Zhu, Z., Tu, Y., & Yang, X. (2018). Confined assembly of hollow carbon spheres in carbonaceous nanotube: a spheres‐in‐tube carbon nanostructure with hierarchical porosity for high‐performance supercapacitor. Small, 14(19), 1704015.

[2] Mendes, R. G., Wróbel, P. S., Bachmatiuk, A., Sun, J., Gemming, T., Liu, Z., & Rümmeli, M. H. (2018). Carbon nanostructures as a multi-functional platform for sensing applications. Chemosensors, 6(4), 60.