A Supramolecular Network as Sacrificial Mask for the Generation of a Nanopatterned Binary Self‐Assembled Monolayer

Abstract

Supramolecular self-assembly on surfaces has become a straightforward and flexible route for the generation of extended nanoscale structures, with porous networks serving as templates to control the arrangement of metal clusters or guest molecules. The latter includes thiols, which are particularly interesting as they afford an enormous flexibility in surface functionalization. Recently we have shown that a supramolecular network of perylene-tetracarboxylic di-imide (PTCDI) and 1,3,5-triazine-2,4,6-triamine (melamine), which involves a triple hydrogen bonding motif (Figure 1a), can be used as a template for an all-solution-based generation of periodic patterns of thiol self-assembled monolayer (SAM) nanoislands on Au(111) (Figure 1b). These network–SAM hybrid structures can be further processed in an electrochemical environment, as demonstrated by underpotential deposition (UPD) of Cu, where one atomic layer of the metal intercalates at the SAM–substrate interface but not between network and substrate (Figure 1c). While formation and modification of network–SAMhybrids demonstrate the robustness of the PTCDI–melamine network, it is nevertheless of limited stability as evidenced by its displacement upon prolonged exposure to a thiol solution. Since the formation of hybrid structures is a kinetically controlled process, substitution of the network by thiols different to those in the network pores is a potential way to produce binary SAMs (Figure 1d) over extended areas with resolution and pattern definition unmatched by other approaches such as random insertion,mixing, or lithographic techniques.However, the feasibility of this approach critically depends on the properties of the thiol islands filling the nanopores. One evident issue is their stability against replacement by the second thiol species that depends on a number of mutually dependent factors such as molecule–substrate bond strength, intermolecular interactions,