Novel blue light emitting graphene oxide nanosheets fabricated by surface functionalization

Graphene and graphene oxide (GO) attract increasing attention due to their unique physical and chemical properties and thus the potential applications in optics and electronics. However, the gapless band structure greatly limits their wide applications in opto-electronic devices. Surface functionalization was found to be an effective method to tune the properties of graphene and GO. In the present report, GO hybrid materials with blue-emission were fabricated through the GO surface functionalization with aryl diazonium salts of 2-aminoanthracene. The obtained hybrids were carefully characterized with atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Fourier-transformed infrared spectroscopy (FTIR), Raman spectroscopy and UV-Vis absorption spectroscopy. Significantly different from the cyan emission (similar to 491 nm) of monomeric 2-aminoanthracene, the as-synthesized GO hybrid composites exhibited strong blue photoluminescence centered at ca. 400 nm. The large blue shift of the luminescence (similar to 91 nm) obtained from the functionalized GO could be partly ascribed to the rigid chemical environment with anthryl moieties chemically bonded onto GO surface. Such surface-functionalized GO hybrids with unique optical properties render them exciting materials for opto-electronic devices.