A comprehensive investigation of structural, optical, morphological, and electrical properties of CuO-NPs synthesized by pulsed laser ablation in water: effect of laser fluence

In this paper, the laser ablation method was utilized to synthesize Copper (II) oxide nanoparticles (CuO-NPs) using a Q-switched laser at varied laser fluences. The X-ray diffraction (XRD), absorbance spectra, fluorescence, field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray (EDX), atomic force microscopy, and electrical properties were investigated. The results showed that CuO-NPs were synthesized effectively in an aqueous medium at various laser fluences. XRD examination revealed that the CuO-NPs increased in quantity and crystallinity with raised laser fluence, confirming the formation of CuO-NPs. UV–visible spectra confirmed that the absorbance values of the CuO-NPs increased with increasing laser fluence with a decreased band gap of (3.8–3.4) eV. The PL data showed peaks centered on (372, 377) nm, and the PL intensity of the CuO-NP samples rose as the concentration of CuO-NPs increased. Additionally, the quantum confinement effect may be responsible for the redshift in the peak of the PL emission band. The surface morphology of the CuO-NPs was examined using AFM and FE-SEM, which indicated the production of diverse NP morphologies such as platelets, as well as semi-spherical and spherical particles with varying diameters. The results obtained from the EDX study indicated that the O/Cu ratio concentration increased when the laser fluence was increased. This might be attributed to the occurrence of oxidation processes. The electrical characteristics revealed a rise in electrical conductivity from (92.2 × 10^–5 to 113.2 × 10^–5 Ω/cm) and average activation energy values of (0.0871 and 0.0893 eV) in the optimal sample.