Visible-Light Azidation and Chemical Patterning of Graphene via Photoredox Catalysis

We report a photocatalytic approach for the facile azidation and chemical patterning of graphene. Employing the classic photoredox catalyst tris(bipyridine)ruthenium(II) chloride, [Ru-(bpy)3]Cl2, azidyl radicals are generated in an aqueous solution of sodium azide under low illumination of blue light, e.g., filtered out from a white lamp. The photogenerated azidyl radicals efficiently azidate monolayer graphene, and the resultant azidated graphene further enables chemically defined derivations through click chemistry and subsequent bioconjugation. By controlling the illumination pattern in the wide field, we further demonstrate the direct photopatterning of graphene functionalization with low light, removing the need to focus an intense laser beam into a tight spot.