Sujet de stage / Master 2 Internship

The term graphene covers a whole family of materials. In this internship, we propose to build by organic synthesis methods graphene nanoparticles for the study of their optical properties and which can serve as a basic brick for the realization of graphene materials.

Graphene is a two-dimensional material originally derived from graphite. One of the major limitations to the use of graphene, particularly in optics and electronics, is the absence of a bandgap; graphene is in fact a semi-metal. One way to open a "gap" in graphene is to reduce one or both of its dimensions to nanometric scales, thus forming graphene nanoribbons or nanoparticles. Another method is to form a regular network of holes in graphene, known as "graphene nanomesh". Over the last ten years or so, several groups have been interested in building and studying these structures using the "top-down" approach, i.e. by forming nanostructures from the macroscopic material via chemical oxidation processes, plasma etching, etc.[1-3] The drawback of the "top-down" method is that it does not allow precise control of the structure of the final material. Moreover, it has been shown that optical and electronic properties are largely influenced by edge effects and oxidation states. In contrast, the synthesis of graphene materials by chemical synthesis ("bottom-up" approach) enables the structures to be controlled down to the atom. [4,5]

The aim of this project is to synthesize graphene materials (graphene nanoparticles, graphene nanomesh) using the bottom-up approach, i.e. via organic chemistry reactions (palladium coupling, Diels-Alder, Scholl reaction, etc.). As part of a collaboration with ENS Paris-Saclay (LUMIN laboratory), several nanoparticles has been synthesized at LICSEN, and their ensemble and single-molecule properties studied at LUMIN. These particles are shown to exhibit both the interesting properties of molecules : small size, large effective absorption cross-section, possibility of tuning their properties through organic chemistry, and those of solid emitters like the colored centers of diamond : high brilliance and good photostability [6-8].

During this internship, new families of graphene nanoparticles will be synthesized, and we'll also be looking at the synthesis of graphene nanomesh precursors. This is primarily a molecular chemistry internship, and we will be using conventional chemistry techniques (fume cupboard chemistry, inert atmosphere work, vacuum/argon ramp, etc.). Classical characterization techniques: NMR spectroscopy, abs. UV-Vis-NIR, photoluminescence and mass spectrometry (MALDI-TOF).

For this project, the candidate should have a solid background in organic chemistry. The project will be carried out in collaboration with physicists; the candidate should also have a good feeling for multidisciplinary work. This work may be continued in a PhD thesis.

References :
[1] D. V. Kosynkin, A. L. Higginbotham, A. Sinitskii, J. R. Lomeda, A. Dimiev, B. K. Price, J. M. Tour, Nature 2009, 458, 872-877.
[2] L. Jiao, L. Zhang, X. Wang, G. Diankov, H. Dai, Nature 2009, 458, 877-880.
[3] L. Li, G. Wu, G. Yang, J. Peng, J. Zhao, J.-J. Zhu, Nanoscale 2015, 5, 4015-4039.
[4] A. Narita, X. Y. Wang, X. Feng, K. Müllen, Chem. Soc. Rev. 2015, 44, 6616-6643.
[5] J. Pijeat, J.-S. Lauret, S. Campidelli. "Bottom-up approach for the synthesis of graphene nanoribbons", (Eds.: L. Brey, P. Seneor, and A. Tejeda), Graphene Nanoribbons, IOP Publishing Ltd, 2020, p. 2.1-2.25.
[6] S. Zhao, J. Lavie, L. Rondin, L. Orcin-Chaix, C. Diederichs, P. Roussignol, Y. Chassagneux, C. Voisin, K. Müllen, A. Narita, S. Campidelli, J.-S. Lauret, Nat. Commun. 2018, 9, 3470
[7] T. Liu, C. Tonnelé, S. Zhao, L. Rondin, C. Elias, D. Medina-Lopez, H. Okuno, A. Narita, Y. Chassagneux, C. Voisin, S. Campidelli, D. Beljonne and J.-S. Lauret, Nanoscale, 2022, 14, 3826-3833.
[8] D. Medina-Lopez, T. Liu, S. Osella, H. Levy-Falk, N. Rolland, C. Elias, G. Huber, P. Ticku, L. Rondin, B. Jousselme, D. Beljonne, J.-S. Lauret and S. Campidelli, Nat. Commun., 2023, 14:4728.