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The vast potential of organic materials for electronic, optoelectronic and spintronic devices entails substantial interest in the fabrication of -conjugated systems with tailored functionality directly at insulating interfaces. On-surface fabrication of such materials on non-metal surfaces remains to be demonstrated with high yield and selectivity. Here we present the synthesis of polyaromatic chains on metallic substrates, insulating layers, and in the solid state. Scanning probe microscopy shows the formation of azaullazine repeating units on Au(111), Ag(111), and h-BN/Cu(111), stemming from intermolecular homo-coupling via cycloaddition reactions of CN-substituted polycyclic aromatic azomethine ylide (PAMY) intermediates followed by subsequent dehydrogenation. Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry demonstrates that the reaction also takes place in the solid state in the absence of any catalyst. Such intermolecular cycloaddition reactions are promising methods for direct synthesis of regioregular polyaromatic polymers on arbitrary insulating surfaces. p id=Par A critical milestone for the advancement of nanoscale organic circuitry is the fabrication of well-defined conjugated polymers on non-metal substrates. Here, the authors demonstrate extended polycyclic aromatic chains from repetitive cycloadditions which form not only on metals, but also on boron nitride layers and in the solid state.

In this work, state-of-the-art scanning probe microscopy is used to investigate the interactions between functional molecules and two-dimensional materials at the atomic scale. The fundamental understanding of such hybrid systems is essential for the bottom-up fabrication of nano electronic devices. I.a., we introduce a scalable method to assemble layered heterostructures via porphine intercalation, and develop novel reactions for the on-surface synthesis of covalent nanostructures on h-BN/Cu(111)., In dieser Arbeit wird ein state-of-the-art Rastersondenmikroskop verwendet um die Wechselwirkungen von funktionalen Molekülen mit zweidimensionalen Materialien auf atomarer Skala zu untersuchen. Das fundamentale Verständnis solcher Hybridsysteme ist essentiell für die Bottom-Up Fabrikation nanoelektronischer Strukturen. U.a., führen wir eine skalierbare Methode zur Herstellung von geschichteten Heterostrukturen via Porphine Interkalation ein und entwickeln neue Reaktionen für die Oberflächensynthese von kovalenten Nanostrukturen auf h-BN/Cu(111).

Silver opens up interesting perspectives in the fabrication of complex systems based on heteroepitaxial layers after the growth of a silicene layer on its (111) face has been proposed. In this work we explore different synthesis methods of hexagonal boron nitride (h-BN) and graphene sheets on silver. The resulting layers have been examined by high-resolution scanning tunneling microscopy. A comparison of the interfacial electronic band structure upon growth of the distinct two-dimensional (2D) layers has been performed by scanning tunneling spectroscopy and complementary first-principle calculations. We demonstrate that the adsorption of the 2D layers has an effect on the binding energy of the Shockley state and the surface potential by lowering the local work function. These effects are larger in the case of graphene where the surface state of Ag(111) is depopulated due to charge transfer to the graphene. Furthermore, we show that the electronic properties of the h-BN/silver system can be tuned by employing different thicknesses of silver ranging from a few monolayers on Cu(111) to the single crystal Ag substrate.