Engineering and Technology Journal

Silver nanoparticles (Ag NPs) were prepared by laser ablation of a silver bulk immersed in cetrimonium bromide (CTAB). The immersed sheet was focused by a pulsed Nd:YAG laser at 1064 nm, 600 mJ at room temperature, a pulse duration of 10 ns, and a repetition rate of 5 Hz. The Ag NPs suspension was analyzed using UV–Vis spectroscopy, zeta potential (ZP), the Fourier transform infrared (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The peak at 425 nm was observed in the absorption spectrum of Ag NPs colloidal solution.Ag NPs' colloidal results are 20 mV for positively charged CTAB. The XRD pattern of the NPs revealed the presence of Ag phase planes (111), (200), and (220). All samples show aggregation-induced spherical nanostructures and large particles in FESEM images. The TEM images revealed nearly spherical NPs, with sizes ranging from 5–70 nm, for Ag NPs prepared with CTAB. The Ag NPs with concentrations of (0.0, 25, 50, 100, and 200) µg/mL were tested for antibacterial activity against a clinical isolate of Streptococcus mutans, and the concentrations of (0.0, 50, 75, 100, and 200) µg/mL were tested for in vitro hemocompatibility effects by measuring the hemolysis rate of red blood cells. Ag NPs' antibacterial activity against Streptococcus mutans was size and concentration-dependent, and the hemolysis rate showed low effects at low concentrations, so Ag NPs could be employed to treat and prevent dental caries, but to transform this technology into therapeutic and preventive measures, more investigation and development are required.

In this paper, Silver nanoparticles (Ag NPs) were prepared by laser ablation in liquid (PLAL) technique for different laser energy in water. Then the Ag NPs were deposited on the surface of Si solar cells to enhance their plasmonic absorption. The UV-VIS, FTIR spectrometer, and the Atomic force microscope were used to study the optical properties, composition, and the surface morphology of the NPs, respectively. The atomic absorption spectroscopy was also used to find the amount of ablated material. It is found that after the thermal deposition of the water drops containing Ag NPs on the surface of Silicon solar cells, the short circuit current and the overall conversion efficiency (η) have been improved. The short circuit current density (Jsc) has been increased by 14% after the drop overcasting of Ag NPs (about 92 nm in size) on the surface of silicon solar cells. The relative increase in Jsc may be attributed to the enhance plasmonic absorption for the incident light due to the forward scattering of Ag NPs.

This paper reports our recent studies on the generation of Cu NPs by ablation of metal targets using Q-switch Nd-YAG laser with Second Harmonic Generation(S.H.G) (λ=532nm) immersed in different aqueous media( Double Disteled Deionised Water (DDDW) and 1-Propanol) .Higher productivity and Smallest size have been produced by using 1-propanol solution compared to DDDW, which indicated that the productivity and NPs size were affected by the solution type. Optical properties measurements showed indirect optical energy gap of the produced Cu nanoparticle (3.717 and 4.887) eV , when the solution type change from DDDW to 1-Propanol respectively. The Surface topography studied by Atomic Force Microscopy, and shape were measured by using Scanning Electron Microscope SEM shows spherical shape while the composing of the prepared nanoparticle were determined by X-ray diffraction ,UV-Visible spectroscopy has been employed for the optical properties measurements.

SnO2 nanoparticles were prepared by laser ablation of tin in methanol at room temperature. The particles were characterized by means of TEM, AFM, FTIR, UV-Visible absorption spectrum and electrical properties. AFM micrographs show that the obtained material is spherical nanoparticles, the size and size distribution of which depends on the experimental conditions.
From FTIR spectrum show the peak absorption of SnO2NPssuspension at 657 cm-1.
It is found that the band gap energy of SnO2NPs is higher than that of bulk SnO2 due to the decreases in the particle size according to the quantum confinement model.
From the J-V characteristics Al/SnO2 NPs/c-Si/Al hetrojunction the values of ideality factor for these devices is greater than unity which can be attributed to the recombination of electrons and holes in the depletion region as well as the tunneling effect depending on both sides of the heterojunction and on the presence of defect states.

Noble metal silver NPs was synthesized by pulsed (Q-switched, 1064 nm Nd : YAG) laser ablation of silver metal plates immersed in double distilled and deionized water DDDW.
The formation efficiency of PLAL process was quantified in term of the surface Plasmon extinction SPE peaks. The SPE spectra show a sharp and single peak around 400 nm, indicating the production of pure and spherical Ag.
UV-Visible absorption results confirmed formation of silver particles prepared and atomic force microscope (AFM) indicates the size in nanometer (nm) range.

Carbon nanoparticle was synthesis by pulse laser ablation of graphite target in different solution. Fourier Transform Infrared Spectroscopy (FTIR), Transmission electron microscopy (TEM) and Conductivity meter were used to study chemical composition, size, morphology and condectivity of suspensions. FTIR spectra exhibit the presence of C≡C, C═C, C-C bond which indicates the formation of carbon nanoparticles. The TEM show the formation of spherical nanoparticles, aggregation of the carbon nanoparticles, morphology of carbon nanotube ((141.6 nm length and 16.6 nm diameter) in ethanol, but high-quality of CNTs in Iso-propanol with (11.1–46.15 nm) diameter and (261.1- 592.3 nm) length and the CNTs are uniform diameters in deionize water with diameters (12.2-25 nm) and (500 - 708.3 nm) length). Study the electrical condectivity; determine the activation energy of suspension and the condectivity depended on geometry of carbon nanoparticles; electrical conductivity in ethanol suspension is more than Iso-propanol suspension and the electrical conductivity of deionize water is more than them.

In this work, silver nanoparticles has been prepared via ablation of pure Ag metal target in distilled water was accomplished using Q-switched Nd:YAG laser at (1.06 µm) laser wavelength , with different laser energy and number of laser pulses. The effect of these parameters on the optical and surface morphology have been studied , UV-Visible show a red shift in the absorption spectra related to the shift in the energy gap due to increment of the grain of prepared particles size is increased as laser energy. Grain size of the obtained NPs are found to increase with laser energy with rang (20-112) nm as shown by the SEM result.

Silver and gold nanoparticles were prepared by using nanosecond pulsed laser ablation. Ablation of pure metal targets (Ag and Au) for nanoparticle colloidal production was studied in de-ionized water. The optical properties were studied with Ultraviolet- Visible (UV-Vis) spectrophotometer. The spectra reveal sharp peaks due to surface plasmon absorption peaks at 405 nm and 523 nm for Ag and Au respectively. The size and shape of nanoparticles was investigated by Transmission Electron Microscope (TEM). Spherical shapes with average diameters of 10 nm and 6 nm for silver and gold nanoparticles were found respectively.