Bright green photoluminescence in aminoazobenzene-functionalized graphene oxide

Graphene oxide (GO) enriched in oxygen functionalities is limited in optoelectronic application because of its poor optical behavior. One of the major strategies for developing the optical properties of GO is functionalization. Here, GO sheets are functionalized by aminoazobenzene to achieve an intercalated type structure with interlayer separation of 9.3 Å. Bright green emission is observed in this aminoazobenzene- functionalized GO (AAB-GO). Remarkable enhancement in photoluminescence via surface passivation and excited-state intramolecular proton transfer is noticed in the AAB-GO composite. Density functional theory calculations are also carried out to investigate the stability of the modified structure along with its interlayer separation, the results of which agree well with the experimental results. The estimated energy gap (∼2.73 eV) between the highest occupied molecular orbital and lowest unoccupied molecular orbital is also in agreement with the experimental results (∼2.85 eV) of UV-vis absorption data.