Stabilizing CuPc Coordination Networks on Ag(100) by Ag Atoms

We demonstrate that Ag adatoms are capable of stabilizing negatively charged copper-phthalocyanine (CuPc) molecules in a Ag–CuPc network at room temperature. For this aim, the structure of the Ag–CuPc coordination network at different molecule-adatom densities is investigated experimentally by scanning tunneling microscopy and theoretically by first-principles calculations. The islands formed at saturation adatom density, close to the source of adatoms, consist of a closed-packed layer without voids. The islands formed at lower adatom density consist of an irregular arrangement of larger entities, named subunits, mainly (CuPc) 4 Ag and (CuPc) 6 Ag 2, which are interconnected in the same fashion as the CuPc molecules in the closed-packed layer. Silver adatoms in the subunits and between them differ by the number of molecules they link. The Ag–CuPc networks are stabilized, because the adsorption energy of CuPc molecules increases due to the presence of adatoms.