Covalent Patterning of Graphene: from Sophistication to Simplicity

Abstract

Patterning of graphene (functionalizing some areas while leaving others intact) is challenging, as all the C atoms in the basal plane are identical, but it is also desirable for a variety of applications, like opening a bandgap in the electronic structure of graphene. Several methods have been reported to pattern graphene, but most of them are very technologically intensive. For example, some groups have explored electron beam lithography,[1] or laser writing.[2] Here, we will present the two approaches that we have studied. First, we describe a method to functionalize graphene covalently under ultra-high vacuum conditions and characterized with scanning tunnelling microscopy.[3] We achieve exquisite (>97%) atomic selectivity and yield (92%). The periodic landscape is provided by a single monolayer of graphene grown on Ru(0001) that presents a moiré pattern due to the mismatch between the carbon and ruthenium hexagonal lattices. The moiré contains periodically arranged areas where the graphene–ruthenium interaction is enhanced and shows higher chemical reactivity. Furthermore, we will show how this type of functionalized graphene acts as a catalyst for an unusual and reversible C-C bond forming reaction.[4] Secondly, we will describe easy and scalable protocol for the covalent patterning of graphene based on using microemulsions as templates.[5] This method is technologically trivial and can achieve resolution in the µm range.[1] M. C. Rodríguez González, A. Leonhardt, H. Stadler, S. Eyley, W. Thielemans, S. De Gendt, K. S. Mali, S. De Feyter, ACS Nano 2021, 15, 10618-10627.[2] K. F. Edelthalhammer, D. Dasler, L. Jurkiewicz, T. Nagel, S. Al-Fogra, F. Hauke, A. Hirsch, Angew. Chem., Int. Ed. 2020, 59, 23329-23334; T. Wei, S. Al-Fogra, F. Hauke, A. Hirsch, J. Am. Chem. Soc. 2020, 142, 21926-21931.[3] J. J. Navarro, S. Leret, F. Calleja, D. Stradi, A. Black, R. Bernardo-Gavito, M. Garnica, D. Granados, A. L. Vazquez de Parga, E. M. Perez, R. Miranda, Nano Lett. 2016, 16, 355-361; J. J. Navarro, F. Calleja, R. Miranda, E. M. Pérez, A. L. V. d. Parga, Chem. Commun. 2017, 53, 10418--10421.[4] J. J. Navarro, M. Pisarra, B. Nieto-Ortega, J. Villalva, C. G. Ayani, C. Díaz, F. Calleja, R. Miranda, F. Martín, E. M. Pérez, A. L. Vázquez de Parga, Science Advances 2018, 4, eaau9366.[5] A. Naranjo, N. Martín Sabanés, M. Vázquez Sulleiro, E. M. Pérez, Chemical Communications 2022, 58, 7813-7816.