Researchers from Empa in Switzerland have fabricated graphene-like materials using a surface chemical route and clarified in detail the corresponding reaction pathway. Using a prototypical polyphenylene precursor, the researchers clarified, together with scientists at the Max Planck Institute and the University of Zurich, how the reaction pathway runs in detail on a copper surface and how the building blocks can be transformed into planar nanographenes directly on the surface.

For their investigations the researchers combined empirical observations, in particular from scanning tunneling microscopy with computer simulations. The simulations are used to determine whether a theoretically possible reaction step is energetically possible or not. The result: the reaction pathway consists of six steps with five intermediate products. Two of them are stabilized by the surface so that they can be stably imaged with the scanning tunneling microscope. The reaction barriers connecting the different intermediates are lowered through a catalytic effect of the substrate.