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

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 pi-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.