ORALS

SESSION: NanomaterialsTuePM2-R3	Echegoyen International Symposium (8th Intl. Symp. on Synthesis & Properties of Nanomaterials for Future Energy Demands)
Tue. 28 Nov. 2023 / Room: Dreams 3
Session Chairs: Dirk Michael Guldi; Steven De Feyter; Session Monitor: TBA

16:50: [NanomaterialsTuePM211] OS Invited
FORMATION AND FUNCTIONALIZATION OF 2D MATERIALS: A MOLECULAR APPROACH
Steven De Feyter¹ ; ¹KU Leuven, Leuven, Belgium;
Paper Id: 27 [Abstract]

Two-dimensional materials have interesting properties. Taking full advantage of their characteristics, surface functionalization may be required; In this presentation, I will mainly focus on the functionalization of graphite, graphene, and transition metal dichalcogenides using molecules, though the concepts can also be applied to other 2D materials. Nanostructuring is at the heart of all functionalization protocols that we develop because it opens new possibilities for control and functionality. A variety of scanning probe microscopy methods are used for visualization, characterization, and manipulation. The first approach is based on molecular self-assembly at the interface between a liquid or air, and graphite or 2D materials [1]. A second approach is based on the covalent attachment of molecules on 2D materials via covalent chemistry. It will be demonstrated how top-down scanning probe microscopy and optical lithography can be used to structure such covalently modified surfaces in addition to bottom-up strategies that provide control on the density and layer thickness, as well as submicron to nanoscale nanostructure [2,3,4]. Covalently modified surfaces can for instance be implemented for sensing purposes [5]. A third approach does not focus on the functionalization of the surface, but uses the surface as a support for the in-plane covalent stitching of molecules, leading to the formation of on-surface 2D dynamic covalent polymers [6,7]. A variety of molecule-based functionalization strategies, and combinations thereof, lead to unique substrate architectures, as revealed by local scanning probe microscopies.

References:
[1] A. Cucinotta, C. Kahlfuss, A. Minoia, S. Eyley, K. Zwaenepoel, G. Velpula, W. Thielemans, R. Lazzaroni, V. Bulach, M. Wais Hosseini, K. S. Mali, and S De Feyter, J. Am. Chem. Soc., 145, 2, 1194–1205 (2023) [2] L. Verstraete, S. De Feyter, Chem. Soc. Rev., 50, 5884 (2021) [3] K. Tahara, Y. Kubo, S. Hashimoto, T. Ishikawa, H. Kaneko, A. Brown, B. E. Hirsch, S. De Feyter, Y. Tobe, J. Am. Chem. Soc. 16, 7699 (2020) [4] M. C. Rodríguez González, A. Leonhardt, H. Stadler, S. Eyley, W.Thielemans, S. De Gendt, K. S. Mali, S. De Feyter, ACS Nano, 6, 10618 (2021) [5] S. Freddi, M. C. Rodriguez Gonzalez, P. Carro, L. Sangaletti, S. De Feyter, Angew. Chem. Int. Ed., 61, e202200115 (2022) [6] G. Zhan, Z.-F. Cai, M. Martínez-Abadía, A. Mateo-Alonso, S. De Feyter, J. Am. Chem. Soc., 13, 5964 (2020) [7] G. Zhan, Z. F. Cai, K. Strutyński, L. Yu, N. Herrmann, M. Martinez-Abadia, M. Melle-Franco, A. Mateo-Alonso, S. De Feyter, Nature, 603, 835 (2022)

SESSION: SolidStateChemistryThuAM-R4	Poeppelmeier International Symposium(3rd Intl Symp on Solid State Chemistry for Applications & Sustainable Development)
Thu. 30 Nov. 2023 / Room: Dreams 4
Session Chairs: Steven De Feyter; Session Monitor: TBA

11:35: [SolidStateChemistryThuAM01] OS
CHEMICAL PATTERNING OF GRAPHENE AND GRAPHITE: FROM MICROSCALE TO NANOSCALE
Kunal Mali¹ ; Steven De Feyter² ; ¹KU Leuven, Belgium, Leuven, Belgium; ²KU Leuven, Leuven, Belgium;
Paper Id: 288 [Abstract]

Chemical patterning of graphene is relevant in several different domains of science and technology with exciting possibilities in electronics, catalysis, sensing, and photonics. Despite intense efforts, spatially controlled, (multifunctional) covalent chemical patterning of graphene is not straightforward to achieve. The lack of control primarily originates from the inherently poor reactivity of the basal plane of graphene which necessitates the use of harsh chemistries. In my talk, I will present two examples of covalent chemical patterning of graphene and graphite using diazonium chemistry. In the first case, spatially resolved multicomponent covalent chemical patterning of single layer graphene was achieved using a facile and efficient method. Three different functional groups could be covalently attached to the basal plane in dense, well-defined micrometer wide patterns using a combination of lithography and a self-limiting variant of diazonium chemistry requiring no need for graphene activation. The layer thickness of the covalent films could be controlled down to 1 nm. In the second case, i will present sub-10 nm chemical patterning of graphite achieved using the electrochemical diazonium chemistry.  Here, an elegant combination of covalent and non-covalent chemistry was used to achieve 5-6 nm wide linear chemical patterns with excellent pattern transfer fidelity. Throughout the discussion, i will highlight the critical role of scanning probe microscopy, namely STM, AFM and AFM-IR in providing critical spatial and spatiochemical information at the nanometer scale where conventional analytical techniques fail to provide accurate information. 

References:
[1] ACS Nano 2021, 15, 10618−10627
[2] Nanoscale, 2023, 15, 10295–10305