A group of researchers from Norway (Vasily Saroka), Italy (D. Grassano, O. Pulci) and the Philippines (R. B. Payod, G. N. C. Santos) together with a scientist from the Southern Federal University Dmitry Levshov have developed an "atlas of optical transitions" for the structural identification of graphene nanoribbons. The results of these studies were published in the international scientific journal Nature Communications.

Note that nanoscale forms of carbon, such as graphene, carbon nanotubes, and graphene nanoribbons, are promising materials, in the study of the properties of which considerable efforts and resources are invested all over the world. For example, nanotubes are small cylindrical molecules one carbon atom thick, that is, a hundred thousand times thinner than a human hair. At the same time, they are dense and tough, incredibly light, have unique electrical and thermal properties, and have the potential to develop materials for the future.

Fig 1. Carbon nanotube and corresponding graphene nanoribbons

Carbon nanotubes interact with light in a special way, are able to absorb and emit it at strictly defined frequencies, thus creating a unique optical "fingerprint" (spectrum). Previously, scientists were able to collect a large empirical catalog (atlas) of such spectra, which made it possible to develop reliable methods for structural identification and achieve significant advances in the synthesis and sorting of carbon nanotubes with atomic precision.

A joint study of Norwegian, Italian, Filipino scientists and employees of the Southern Federal University made it possible to create a similar atlas for graphene nanoribbons with zigzag edges. As a result of calculations, the authors found that there is a relationship between the optical properties of well-studied single-walled carbon nanotubes and the properties of graphene nanoribbons, and they proposed a simple 2N + 4 rule to establish a correspondence between their unit cells.

Fig 2. Atlas of optical transitions for graphene nanoribbons with zigzag edges

“The developed atlas of optical transitions opens the way for the rapid structural characterization of nanoribbons with zigzag edges, which is an important stage for their controlled synthesis, as well as their subsequent full-scale implementation in industry, for example, in optoelectronic, photonics and spintronics devices,” concluded Ph.D. m. D., Junior Researcher of the Youth Scientific Laboratory "Structure and Dynamics of Individual Nanosystems" Dmitry Levshov.