Synthesis of reduced graphene oxide–ZnO hybrid with enhanced optical limiting properties

Abstract

Reduced graphene oxide–ZnO (rGO–ZnO) is synthesized by in situ growth of ZnO on the surface of graphene oxide (GO) by facile solution methods; namely, a solution precipitation method and a hydrothermal method. The characterization shows that GO is reduced and exfoliated to graphene sheets and ZnO is partially covered by graphene layers. A formation mechanism of rGO–ZnO hybrid proposed is well suited to the experimental results. Structural analysis indicates that the graphene possesses a greater extent of π-conjugation in the hydrothermally prepared rGO–ZnO hybrid. These hybrids exhibit an intense and broad absorption in the visible region, in addition to the sharp UV absorption peak. These rGO–ZnO hybrids also show fluorescence quenching properties. The nonlinear absorption coefficient and optical limiting properties of rGO–ZnO hybrid is evaluated using an open aperture Z-scan technique. More interestingly, we found that there is a 15 times enhancement in the nonlinear absorption coefficient of the rGO–ZnO hybrid compared to the bare ZnO. The hybrid shows excellent optical limiting properties compared to its individual counterparts, implying the usability of these hybrids in optoelectronics.