Laser Science and Technology
Mayyadah H. Mohsin; Khawla S. Khashan; Ghassan M. Sulaiman; Khalil A. A. Khalil
Abstract
A technique for exfoliating Boron nitride (BN) nanosheets was devised, which was then followed by a laser ablation-fragmentation process to produce lamellar hexagonal Boron nitride nanostructures (h-BNNs). The physicochemical properties of the nanoparticles were analyzed to investigate the effect of ...
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A technique for exfoliating Boron nitride (BN) nanosheets was devised, which was then followed by a laser ablation-fragmentation process to produce lamellar hexagonal Boron nitride nanostructures (h-BNNs). The physicochemical properties of the nanoparticles were analyzed to investigate the effect of laser energy and wavelength in the two-step pre-treatment procedure during BN synthesis. The X-ray diffraction (XRD) patterns showed no impurity phase structures and only primary h-BN reflections were visible. It was discovered that the crystallite h-BNNs size ranged from 11 to 18 nm, and nanosecond laser energy was sufficient to transform BN into h-BNNs and a few nanotubes. Combining laser intensity and wavelength transformed the BN nanoparticle shape from haphazardly arranged platelets to melting-like formations. Fourier Transform infrared (FTIR) spectroscopy confirmed distinct observed changes in the size and melting behavior in the h-BNNs and the sharp absorption peaks which could indicate changes in their optical properties. Morphological characteristics and formation of the hexagonal phase of BN caused variations in optical properties and high-resolution transmission electron microscopy (HRTEM) results. Photoluminescence of h-BNNs was observed in the 250–600 nm range with peak emission at 485 nm. Due to its significant structural disorder, the h-BNNs exhibited a wide emission with a strong luminescence that remained largely continuous after 48 hours, resulting in a distinctive blue hue (470, and 485nm).
Nanotechnology
Israa F. Hasan; Khawla S. Khashan; Aseel A. Hadi
Abstract
Titanium dioxide nanoparticles were produced in this work by laser ablation of a high purity titanium objective immersed in distilled water. Optical and structural properties of the obtained TiO2 NPs using a Q-switched Nd: YAG laser of 1064nm wavelength with different laser energy (80, 100, 120, 140, ...
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Titanium dioxide nanoparticles were produced in this work by laser ablation of a high purity titanium objective immersed in distilled water. Optical and structural properties of the obtained TiO2 NPs using a Q-switched Nd: YAG laser of 1064nm wavelength with different laser energy (80, 100, 120, 140, and 160) mJ at 100 pulses was studied. The produced TiO2 NPs were characterized employing UV-VIS Spectrophotometer, X-ray diffraction, and scanning electron microscopy (SEM). The obtained TiO2NPs showed a decrease in transmittance in the region of the UV spectrum and an increase in the visible spectrum region. The estimated optical band gap of the TiO2NPs was 3.89eV, 3.8eV, and 3.70eV at 80, 120 and 160mJ laser energy, respectively. The as-produced TiO2NPs appear to be a Brookite crystalline phase with the preferential orientation along (200) direction. The scanning electron microscopy assays showed that the TiO2 NPs have a cauliflower shape. Results show that with increasing the energy of laser pulse, the size of nanoparticles was increased noticeably. Where the particle size and its morphology are affected by laser energy.
