Research on two-dimensional materials has inspired great interest because of their unique electronic properties. Molecular self-assembly is a well-known approach for fabricating low-dimensional functional nanostructures. In recent studies [1, 2], heteroatoms-doped precursors have frequently been used to polymerize graphene nanoribbons with a large variety of structures or dopant hetero-atoms. Advances in single-atom/molecule manipulation using the Scanning Tunneling Microscopy (STM) tip have enabled scientists to construct atomic-scale structures and probe the physical phenomena at the atomic level. In this presentation, utilizing 3,9-diboraperylene diborinic acid (B2-Per) as precursors and a controlled on-surface non-covalent synthesis approach, I report the self-assembly of chiral kagome supramolecular networks on the Ag(111) surface. These networks are stabilized by intermolecular hydrogen-bonding interactions at low temperatures. STM and STS measurements reveal a flat band at approximately 0.33 eV above the Fermi level, which is localized at the molecular center, in good agreement with tight-binding model calculations of flat bands characteristic of kagome lattices. These findings have broadened the knowledge of the fabrication of two-dimensional complex supramolecular networks on metal surfaces as well as their electronic properties, providing yet another template on which the nontrivial topology can be tuned [3].

[1] S. Kawai et al. Nat. Commun. 6, 8098 (2015)
[2] M. Telychko et al. Sci. Adv. 7, eabf0269 (2021)
[3] W.-C. Pan et al. Angew. Chem. Int. Ed. 63, e202400313 (2024)