N-graphene synthesized in astrochemical ices
Résumé
In our quest for the presence of large complex molecules containing a majority of carbon in the interstellar medium (ISM), the search for graphene plays a central role due to its nature in making other carbon structures. Although the ingredients for graphene synthesis are present in the ISM, conclusive laboratory evidence of such formation is lacking. Therefore, in our laboratory experiments simulating the cold ISM conditions, we subjected icy mantles of benzonitrile, an aromatic with a cyanide side chain that has recently been detected in the interstellar medium, to vacuum ultraviolet photon irradiation. The irradiated ice was observed to leave a residue upon warming to room temperature. The residue was removed from the substrate and placed on a Quantifoil grid for electron microscopy analysis. Transmission electron microscopy showed quantum dots (QD) and nitrogen-doped graphene (N-Graphene) sheets. Diffraction and energy-dispersive X-ray spectroscopy revealed the crystalline nature and carbon–nitrogen composition, of the observed graphene sheet. This is the first evidence of QD and N-graphene synthesis in ice irradiation at interstellar temperatures. Graphic Abstract: [Figure not available: see fulltext.]. © 2023, The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature.
Mots clés
Aromatic compounds
Energy dispersive spectroscopy
High resolution transmission electron microscopy
Ice
Irradiation
Nitrogen
Semiconductor quantum dots
Benzonitriles
Carbon structures
Complex molecules
Condition
Graphene sheets
Interstellar medias
Laboratory experiments
Side-chains
Synthesised
Vacuum ultraviolets
Graphene