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We report the first synthesis of colloidal lead iodide PbI 2 nanoparticles by pulsed laser ablation in methanol. Structural and optical properties of PbI 2 nanoparticles were investigated. The optical absorption data showed three distinct absorption peaks (Plasmon) at 220, 250 and 302 nm, with a direct optical band gap of 2.82 eV. X-ray diffraction XRD analysis revealed that the synthesized PbI 2 nanoparticles were polycrystalline in nature with hexagonal phase. Transmission electron microscope (TEM) investigation displayed (18-40 nm) spherical PbI 2 nanoparticles. The electrical and photo-response characteristics of PbI 2 nanoparticles/n-Si heterojunction were measured and analyzed.

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Abstract-Titanium dioxide (TiO2) nanoparticles (NPs) colloidal that have been synthesized via Nd-YAG laser technique in pure distilled water. The produced NPs were characterized by UV-Vis absorption spectrophotometer and Transmission Electron Microscope (TEM). The surface Plasmon resonance of the colloidal determined by UV-Vis absorption spectra and the absorption peak located at 200nm. TEM exhibits that the size of NPs ranged between 10-80 nm. The antimicrobial activity was tested against Escherichia coli ATCC (gram negative bacteria) and Staphylococcus aureus ATCC 25923 (gram positive bacteria). Prepared TiO2 NPs exhibited inhibitory activity in both bacteria strains with best selectivity against gram-negative bacteria.

The utilization of metal oxide nanoparticles, especially zinc oxide, is of a great importance in the medical field because of its physical and chemical properties as well as its antimicrobial potential effects. In our study, the ZnO nanoparticles were synthesized by the precipitation method where pH=14. ZnO nanoparticles were characterized by ultraviolet-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscope (AFM). Antifungal activity of the ZnO was tested against candida albicans. The results showed that C. albicans (15 samples) became resistant to the fungal activity after testing its sensitivity to several types of fungal antibiotics. UV-vis spectroscopy, XRD, TEM and AFM showed that this precipitation synthetic method can produce a good quality of ZnO nanoparticles with sizes in the range of nanometer scale. In ZnO NPs (calcined), the inhibition zone diameter of C. albicans was 11 mm at a ZnO NPs concentration of 800 mg/ml, while no inhibition zones were formed at the other concentrations (0.25, 0.5, 1, 2, 10, 50 and 500 mg/ml). Using ZnO NPs (not calcined), the inhibition zone diameter of C. albicans was 24 mm at a concentration of 800 mg/ml, while no inhibition zones were observed at the other concentrations (0.25, 0.5, 1, 2, 10, 50 and 500 mg/ml). In addition, a toxicity test was performed on mice and proved that ZnO NPs are effective against C. albicans with a toxic effect on liver and spleen cells in rats. The aim of this research was to characterize the in vitro activity of ZnO nanoparticles synthesized by the precipitation method against C. albicans of human male pleural fluid using the well diffusion method as well as their toxic effects on both liver and spleen cells in mice.