Synthesis and Superior Optical-Limiting Properties of Fluorene-Thiophene-Benzothiadazole Polymer-Functionalized Graphene Sheets



A polymer based on fluorene, thiophene, and benzothiadazole as the donor–spacer–acceptor triad is covalently coupled to reduced graphene oxide (rGO) sheets via diazonium coupling with phenyl bromide, followed by Suzuki coupling. These polymer–graphene hybrids show good solubility in organic solvents, such as chloroform, tetrahydrofuran (THF), toluene, dichlorobenzene, and N,N-dimethylformamide (DMF), and exhibit an excellent optical-limiting effect with a 532-nm laser beam. The optical-limiting threshold energy values (0.93 J cm−2 for G–polymer 1 and 1.12 J cm−2 for G–polymer 2) of these G–polymer hybrids are better than that of carbon nanotubes (3.6 J cm−2).