Special Lecture (Material Science, Chemistry, TREMS)

7th Feb.(Fri) 2020, 16h00-17h30
Room 107, Lab. of Adv. Res. B（総合研究棟 B）,Univ. Tsukuba

Synthesis and properties ofgraphene related materials:
Graphene oxide and Graphene nanoparticles
Dr. Stéphane Campidelli
Laboratoire d’Innovation en Chimie des Surfaces et Nanosciences (LICSEN), NIMBE, CEA,
CNRS, Université Paris-Saclay, CEA Saclay 91191 Gif-sur-Yvette Cedex, France
The rapid rise of 2-dimensional nanomaterials implies the development of new versatile, highresolution visualization and placement techniques. For example a single graphene layer
becomes observable on Si/SiO2 substrates by optical microscopy because of interference
effects when the thickness of silicon oxide is optimized.1,2 However, differentiating
monolayers from bilayers remains challenging and advanced techniques like Raman mapping,atomic force microscopy (AFM) or scanning electron microscopy (SEM) are more suitable toobserve graphene monolayers. The two first are slow and the third one is operated in vacuum
so that in all cases real-time experiments including notably chemical modifications are notaccessible. Here, we introduce a new wide-field optical microscopy technique: Backside
Absorbing Layer Microscopy (BALM), which uses Anti-Reflection and Absorbing (ARA) layers
to achieve extreme contrast at an interface.3 It combines the vertical sub-nm sensitivity of an
AFM with the versatility and real-time imaging capabilities of an optical microscope. We
demonstrate that this technique allows imaging very easily 2D materials like graphene oxideand MoS2, both in air and in water, with extremely high resolution.
Despite its outstanding electronic, optical and mechanical properties, the use of graphene forreal-world applications is severely limited because of its semi-metallic character. It is wellknown that when a material is reduced to nanoscale dimensions, the electronic confinement
induces original size-dependent properties. For the last decade, a great attention has been
paid to the size reduction of graphene using conventional “top-down” approaches(lithography and etching, thermal treatments and oxidation of bulk materials) to fabricate
graphene quantum dots (GQDs)4 or graphene nanoribbons (GNRs).5 However, the “top-down”
approaches do not allow a sufficient control of the structure of the material and of theoxidation state of the edges, which drastically impact the properties. In order to truly control,with the required level of precision, the morphology and the composition of the materials andof its edges, the bottom-up approach is the relevant way to proceed.6,7 Here, I’ll present the“bottom-up” synthesis of graphene quatum dots and the first investigation of thephotoluminescence (PL) properties of at the single molecular-scale. The GQDs exhibited
emission of single photons at room temperature with high brightness and purity.8
References
1. Blake, P.; Hill, E. W.; Castro Neto, A. H.; Novoselov, K. S.; Jiang, D.; Yang, R.; Booth, T. J.; Geim, A. K. Appl.
Phys. Lett. 2007, 91, 063124.
2. Roddaro, S.; Pingue, P.; Piazza, V.; Pellegrini, V.; Beltram, F. Nano Lett. 2007, 7, 2707-2710.
3. Campidelli, S.; Abou Khachfe, R.; Jaouen, K.; Monteiller, J.; Amra, C.; Zerrad, M.; Cornut, R.; Derycke, V.;
Ausserré, D. Sci. Adv. 2017, 3, e1601724.
4. Bacon, M.; Bradley, S. J.; Nann, T. Part. Part. Syst. Charact. 2014, 31, 415-428.
5. Xu, W.; Lee, T.-W. Mater. Horiz. 2016, 3, 186-207.
6. Wu, J.; Pisula, W.; Müllen, K. Chem. Rev. 2007, 107, 718-747.
7. Narita, A.; Wang, X. Y.; Feng, X.; Müllen, K. Chem. Soc. Rev. 2015, 44, 6616-6643.
8. Zhao, S.; Lavie, J.; Rondin, L.; Orcin-Chaix, L.; Diederichs, C.; Roussignol, P.; Chassagneux, Y.; Voisin, C.;
Müllen, K.; Narita, A.; Campidelli, S.; Lauret, J.-S. Nat. Commun. 2018, 9, 3470.

Associate Prof. Seiya Tsujimura (5358, seiya@ims.tsukuba.ac.jp)