Si and CuO nanoparticles as decoration of graphene nanosheets by pulsed laser ablation method

In this study, graphene nanosheets and their nanocomposites with Si and CuO nanoparticles were synthesized using a green and controllable method based on pulsed laser ablation in liquid (PLA). A Q-switched Nd: YAG laser (1064 nm, 7 ns) was employed to ablate a graphite target in distilled water, producing few-layer graphene with a low defect density (I D /I G ratio ≈ 0.54, sp 2 domain size ≈ 8.14 nm). Si/graphene nanocomposites were prepared by UV-assisted decoration, while CuO/graphene nanocomposites were synthesized by ablating a copper target in a graphene suspension under different laser fluences. Comprehensive characterizations using Raman spectroscopy, UV–Vis spectroscopy, Tauc bandgap analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) confirmed the structural, optical, and morphological features of the materials. The optical bandgap energies of the nanocomposites were tunable in the range of 2.84–3.65 eV depending on nanoparticle type, concentration, and synthesis conditions. SEM and TEM analyses confirmed uniform Si nanoparticle decoration and CuO aggregation at higher fluence, demonstrating that synthesis parameters strongly influence morphology and electronic properties. These findings highlight the potential of PLA as an eco-friendly, surfactant-free approach for engineering graphene-based nanocomposites with tunable optoelectronic properties.