Hierarchical Assembly and Sensing Activity of Patterned Graphene-Hamilton Receptor Nanostructures

Structuring distinct building blocks on graphene can open enormous opportunities for constructing well-ordered hierarchical 2D architectures and multifunctional devices useful in numerous practical applications. However, such highly integrated graphene nanostructures featuring functional building blocks remain elusive and the reported graphene 2D-patterning examples are up to now limited to small addends without easily accessible anchor points. Herein, the first realization of patterning extensible building blocks on graphene is presented, in which Hamilton receptor units as characteristic motifs are efficiently patterned onto monolayer graphene by combining the mask-assisted patterning technique and the reductive K/Na activation/functionalization of graphene. This further enables, for the first time, a hierarchical assembly of nanoparticles on graphene, by taking advantage of the hydrogen-bond mediated binding between the Hamilton receptors structured on graphene and cyanurate moieties bound on TiO₂ nanoparticles. The grafting of nanoparticles on graphene is fully reversible upon breakage of the supramolecular interaction within the Hamilton receptor/cyanurate pair by acetone. The structure and stability of Hamilton receptors on graphene and their interaction with cyanurate are confirmed by theoretical calculations. Moreover, the integration of this graphene nanostructure with Hamilton receptors into field-effect transistors allows for an ultrasensitive and quantitative detection of cyanurate/barbiturate moiety down to the 1 × 10⁻⁶ m level.