A series of graphene oxide (GO)/noble metal (Au, Pt, and Pd) nanoparticle (NP) composites were synthesized via a one-step hydrothermal reaction of HAuCl₄, H₂PtCl₆, and Pd(C₂H₃O₂)₂ in the presence of GO. The metal NPs with different average sizes and distributions were uniformly deposited onto the GO surface. The GO structure was conserved after loading with Au, Pt, and Pd NPs. The corresponding nonlinear optical (NLO) and optical limiting (OL) properties were investigated using an open-aperture Z-scan technique with nanosecond pulses at 532 nm. The results show that the NLO and OL properties were significantly enhanced after the inclusion of metal NPs on the GO surface because of nonlinear scattering (NLS) effects. These enhancements depend on the type of loading metal NPs. The GO/Au-NP composite exhibits the optimal NLO and OL performances among the studied composites because of the surface plasmon resonance of the Au NPs. Thus, the NLO and OL effects of the two-dimensional GO can be effectively modified by absorbing different metal NPs on its surface. The synthetic NLO and OL properties in the GO/metal NP composites originate from the reverse saturable absorption in the GO sheets and the NLS in metal NPs. All of the results indicate that these composites can be used in optoelectronic applications.

A novel nanocomposite hybrid, carbon quantum dots (CQD)/graphene oxide (GO), which combines the favorable optical properties of both its components, is synthesized by a facile one-step electrochemical method. Transmission electron microscopy, Raman spectroscopy, UV-vis spectroscopy, and fluorescence studies show that the CQDs uniformly attach on the GO surface, which enables highly efficient energy transfer between CQDs and GO. The nonlinear optical and optical limiting (OL) performances are investigated by the open-aperture Z-scan technique in the nanosecond regime using a laser with a wavelength of 532 nm. The as-prepared CQD/GO composite offers a significantly improved OL performance compared with GO because of the charge/energy transfer process between the CQDs and GO. The main contributors to the enhanced OL effect in the CQD/GO hybrid are a combination of nonlinear scattering and increased nonlinear absorption resulting from efficient charge/energy transfer at the CQD/GO interface.

Hg-based chalcogenides, Hg₃AsS₄Cl and Hg₃AsS₄Br, are synthesized, which show superior comprehensive linear and nonlinear optical properties for promising IR applications.