Dresden 2026 – scientific programme

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O: Fachverband Oberflächenphysik

O 69: Nanostructures at surfaces:1D, 2D, networks – Poster

O 69.6: Poster

Wednesday, March 11, 2026, 18:00–20:00, P2

Tuning electronic properties in 2D Covalent Organic Frameworks via on-surface chemistry — •Mira Sophie Arndt¹, Christoph Wachter², Roman Pallach³, Yan Yan Grisan Qiu⁴, Simone Mearini⁴, Vitaliy Feyer⁴, Sebastian Henke³, Oliver T. Hofmann², Mirko Cinchetti¹, and Giovanni Zamborlini⁵ — ¹Departement of Physics, TU Dortmund, Otto-Hahn-Straße 4, 44227 Dortmund, Germany — ²Institute of Solid State Physics, NAWI Graz, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria — ³Department of Chemistry, TU Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund, Germany — ⁴Peter Grünberg Institute (PGI-6), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany — ⁵Institute of Physics, NAWI Graz, University of Graz, Universitätsplatz 5, 8010 Graz, Austria

Two-dimensional covalent organic frameworks (2D COFs) arranging in a Kagome lattice exhibit intriguing electronic properties, like flat bands and Dirac cones. We investigate the carbonyl-bridged aza-triangulene (P²TANGO), which assembles into a Kagome lattice on Au(111). Inspired by reports that deoxygenation of the precursor induces an open-shell triplet ground state, we explore hydrogen-assisted deoxygenation to tune the COF’s electronic properties. Our angle-resolved photoemission measurements reveal changes in the electronic structure upon oxygen removal, including energy shifts of the dispersive valence band features. DFT confirms that the shift grows with the deoxygenation, and that, in case of a complete deoxygenation, the degeneracy between the flat bands and the Dirac-dispersing bands is lifted.

Keywords: 2D Covalent Organic Frameworks; Band structure engineering; Kagome Lattices; On-surface synthesis