Planar BN-Doped Nanographenes on Reactive Metal Surfaces: A Promising Pathway for the Preparation of BN-Doped Graphene Layers

Boron nitride (BN)-substituted nanographene molecules are currently the focus of interest because the substitution of C-C units by isoelectronic and isosteric BN units is a straightforward way for tuning of their electronic properties. We investigated interface properties of BN-doped B3N3-hexa-peri-hexabenzocoronene (BN-HBC) and B3N3-hexabenzotriphenylene (BN-HBP) on metals with different reactivities using photoelectron spectroscopy (PES). As a reference, HBC was studied on Au(111), Cu(111), and Ni(111) by PES and scanning tunneling microscopy. The substitution of the inner benzene ring of HBC by a borazine core changes the nature of the interaction in the case of more reactive Cu(111) and Ni(111) substrates. Whereas for the planar BN-HBC, chemical interaction occurs mainly via outer C atoms, the inner BN ring is affected in the case of the nonplanar BN-HBP. The stability of the inner ring is expected to be a prerequisite for a successful preparation of well-defined, large-area, BN-doped graphene layers from bottom-up synthesis.

Automated summary

Substituting C-C units with isoelectronic and isosteric BN units is a straightforward way to tune the electronic properties of BN-substituted nanographene molecules. The interface properties of BN-doped molecules depend on the reactivity of the metal substrate and the structure of the molecule. The stability of the inner ring is crucial for successful preparation of large-area BN-doped graphene layers.