Stabilizer as an Order Parameter: Bridging Chemistry and Photonics in Gold Nanoclusters

Abstract

Gold nanoclusters are tiny particles less than 2 nanometers in size. Because they are so small, they occupy a special place between individual atoms and bulk metal. Their main "superpower" is strongly amplifying light signals, which is crucial for detecting minuscule amounts of substances. This effect comes from plasmon resonance – a collective oscillation of electrons on the particle surface driven by light.
However, to work properly, these clusters must be protected from sticking together. This is done using special substances called stabilizers. The type of stabilizer greatly affects particle size, stability in solution, absorption colour, and even luminescence. Experiments show that by choosing the right stabilizer, we can deliberately tune the optical properties of the clusters.
All the clusters studied were smaller than 2 nm, giving them a huge surface‑to‑volume ratio. This helps enhance signals in Raman spectroscopy – a technique that "sees" molecules by their characteristic vibrations. Tests confirmed strong signal enhancement and extremely high sensitivity, capable of detecting even tiny changes around the clusters.
Thus, gold nanoclusters are not just a lab curiosity. They can serve as the basis for ultra‑sensitive sensors, new optical devices, and analytical methods. Most importantly, by changing the stabilizer, we can "tune" them for specific tasks, opening broad prospects in optics and photonics. The study was supported by FSMG-2024-0014 and Prioritet-2030.

Speaker

Anna Abramova
Center for Photonics and 2D Materials, Moskow Institute of Physics and Technology
Russia

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