Azobenzene-functionalized graphene nanoribbons: bottom-up synthesis, photoisomerization behaviour and self-assembled structures

Abstract

Azobenzene-functionalized graphene nanoribbons (GNRs) were synthesized through acid promoted alkyne benzannulation. The resulting GNRs showed high dispersibility in common organic solvents (up to 100 mg mL⁻¹ in chlorobenzene) and underwent fast photoisomerization. A photostationary state was established in solution upon 365 nm light irradiation for 20 s and subsequently the initial state could be easily restored upon 500 nm light irradiation for 40 s. Photo-responsive GNR thin films were also prepared by spin coating. Moreover, the azobenzene-functionalized GNRs could self-assemble into nanowires with lengths ranging from several to tens of micrometers. This study opens an avenue for the functionalization of GNRs with stimuli-responsive functional groups, which holds great promise for applications in optoelectronic devices.