Gathering insights on carbon dots formation with a combined spectroscopic approach


Carbon nanodots are an emerging set of nanomaterials exhibiting interesting properties for basic and applied research. Thanks to features such as photoluminescence and biocompatibility, this technology has relevant applications in medical diagnosis, cancer therapies, and even solar cells. However, the formation mechanisms of carbon nanodots are not entirely known.

Prof. Heinz Amenitsch (Graz University of Technology) and Prof. Maurizio Prato (University of Trieste, CIC biomaGUNE, Ikerbasque) coordinated a research published in Nature Communications where several spectroscopic techniques were employed to elucidate the formation steps of carbon nanodots. Among the applied techniques there is Small- and Wide-Angle X-Ray Scattering (SWAXS), available at the SAXS beamline at the Austrian CERIC Partner Facility at Elettra Sincrotrone Trieste (Italy).

Scheme of the microwave (MW)-assisted synthetic procedure and work up. Three constituents resulted within the reaction mixture (RM): (i) large aggregates (LA – extracted by filtration), (ii) small particles (SP – extracted by dialysis), and (iii) final carbon nanodots (CNDs) (Source:, Credits to the original authors of the research article)

The carbon nanodots, which can be built with cheap and accessible procedures, were made from arginine, an amino acid, and ethylenediamine, a building block for chemical synthesis. The observations demonstrated that the formation of carbon nanodots consists of four different structural steps: aggregation of small organic molecules, construction of a dense core with an extended shell, collapse of the shell, and its change of chemical nature.

Carbon nanodots were accidentally discovered in 2004 during the purification of carbon nanotubes and since then attracted much attention by industrial and academic research. Due to their biocompatibility can be used for diagnostic purposes, as a biosensor, for drug delivery in cancer therapies, and even enhancement of latent fingerprints in criminal investigations. The application of high-resolution techniques has been essential to resolve the pathway of the carbon nanodots formation and its by-products.


Snapshots into carbon dots formation through a combined spectroscopic approach. Rigodanza F., Burian M., Arcudi F., Đorđević L., Amenitsch H., & Prato M., Nature communications, 2021.


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