Enhanced reverse saturable absorption in graphene/Ag2S organic glasses

Abstract

G/Ag₂S composites were synthesized for the first time by a hydrothermal method. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analysis demonstrated that Ag₂S nanoparticles with a diameter of about 130 nm uniformly covered the graphene surfaces. G/Ag₂S composites were dispersed in methyl methacrylate (MMA), polymerized at 75 °C for 30–35 min, and finally dried at 45 °C for 10 h, to afford G/Ag₂S/PMMA organic glasses. The nonlinear absorption (NLA) properties of the G/Ag₂S/PMMA organic glasses with different amounts of G/Ag₂S were investigated by an open-aperture Z-scan technique. The experimental results showed that the G/Ag₂S/PMMA organic glass with an appropriate amount of G/Ag₂S exhibited enhanced reverse saturable absorption (RSA) properties compared to G/PMMA and Ag₂S/PMMA organic glasses, which was attributed to the notable synergistic effects between graphene and Ag₂S. Both one-photon absorption (OPA) in Ag₂S and two-photon absorption (TPA) in graphene played important roles in RSA processes of the G/Ag₂S/PMMA organic glasses. The effective NLA coefficient β_eff of the G/Ag₂S/PMMA organic glasses was in the order of 10³ cm GW⁻¹. Thus this kind of organic glasses have great promise in optical limiter and optical shutter applications.