Spatially Resolved Covalent Functionalization Patterns on Graphene.

Spatially resolved functionalization of 2D materials is highly demanded but very challenging to achieve. The chemical patterning is typically tackled by preventing contact between the reagent and material, which brings various accompanying challenges. Photochemical transformation on the other hand inherently provides remote high spatiotemporal resolution using the cleanest reagent-a photon. Herein, we combine two competing reactions on a graphene substrate to create functionalization patterns on a micrometer scale via the Mitsunobu reaction. The mild reaction conditions allow introduction of covalently dynamic linkages, which can serve as reversible labels for surface- or graphene-enhanced Raman spectroscopy characterization of the patterns prepared. The proposed methodology thus provides a pathway for local introduction of arbitrary functional groups on graphene.