Molecular embroidering of graphene

Abstract

Structured covalent two-dimensional patterning of graphene with different chemical functionalities constitutes a major challenge in nanotechnology. At the same time, it opens enormous opportunities towards tailoring of physical and chemical properties with limitless combinations of spatially defined surface functionalities. However, such highly integrated carbon-based architectures (graphene embroidery) are so far elusive. Here, we report a practical realization of molecular graphene embroidery by generating regular multiply functionalized patterns consisting of concentric regions of covalent addend binding. These spatially resolved hetero-architectures are generated by repetitive electron-beam lithography/reduction/covalent-binding sequences starting with polymethyl methacrylate covered graphene deposited on a Si/SiO2 substrate. The corresponding functionalization zones carry bromobenzene-, deutero-, and chloro-addends. We employ statistical Raman spectroscopy together with scanning electron microscopy/energy dispersive X-ray spectroscopy for an unambiguous characterization. The exquisitely ordered nanoarchitectures of these covalently multi-patterned graphene sheets are clearly visualized.