Rational synthesis of atomically precise graphene nanoribbons directly on metal oxide surface*

Graphene nanoribbons (GNRs) are attracting great interest due to their highly tunable electronic, optical, and transport properties. On-surface synthesis has enabled realization of atomically precise GNRs. However, these bottom-up fabrication methods are based on metal-surface assisted chemical reactions, where interaction with metallic substrates screen the designer electronic properties. Here, we report a methodology for rational precursor design and direct synthesis of atomically precise GNRs on metal oxide surfaces: [1]. The thermally triggered multistep transformations rely on highly selective and sequential activations of C-Br, C-F bonds and cyclodehydrogenation. Scanning tunneling microscopy and spectroscopy (STM/S) characterization monitors in situ the formation of intermediates and GNRs revealing anticipated weak interaction between GNRs and the model rutile TiO₂(011)-(2×1) substrate.

[1] Kolmer et al., Science 369, 571–575 (2020).