Speaker
Description
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.