In this paper, the effect of Nd:YAG laser wavelength and energy on the synthesis of gold nanoparticles is reported. Gold nanoparticles colloidal solutions were prepared by pulsed laser ablation of gold target in deionized water. The Nd:YAG laser with repetition rate of 1 Hz was assigned to supply energy at fundamental and second harmonic wavelengths i.e., 1064 nm and 532 nm, respectively. Synthesized nanoparticles were characterized using particle size analyzer (PSA). Four different laser energies were used to ablate the samples and synthesize gold nanoparticles. The average size of gold nanoparticles was found to decrease with increasing laser energy. The gold nanoparticles of smaller size were obtained when the target was ablated with 532nm wavelength of Nd:YAG laser. Higher laser energies and efficient absorption of 532 nm wavelength resulted in size reduction by fragmentation of colloidal nanoparticles.
Customized cinnamon-based nanostructures are of great demand for broad arrays of nanomedical, biomedical and photocatalytic purposes. Conventional methods for cinnamon nanomaterials production with desirable optical absorption and emission properties are still limited. This communication elucidates the role of growth media (liquid ethanol and methanol) in controlling the optical qualities of cinnamon nanoparticles (CNPs). Such CNPs of varied morphologies were prepared using pulsed laser ablation in liquid (PLAL) technique (a simple, an inexpensive, and an eco-friendly approach). In the PLAL process, clean cinnamon sticks (as target material purchased from supermarket) were ablated via Q-switched Nd:YAG laser pulse of wavelength 532 nm operated at optimum fluence of 5.73 J/cm2. As-synthesized CNPs were characterized at room temperature using ultraviolet-visible (UV-Vis) absorption and photoluminescence (PL) emission spectroscopy. Uniformly dispersed high purity colloidal CNPs with narrow size distribution was achieved. The UV-Vis absorption and the PL spectra of CNPs revealed prominent peaks. These observed distinctive absorption and emission traits of studied CNPs were ascribed to the effects of oxygen deficiency, quantum confinement, crystal defects and existence of cinnamaldehyde compounds. In short, the nucleation and growth of CNPs was significantly sensitive to the chemical character of liquid suspension that provided a favorable thermodynamic condition via entropy driven free energy minimization. It was demonstrated that the structural, morphological, physical, optical properties of such CNPs can be tailored by intuitively selecting the liquid growth media. This disclosure affirmed that the present systematic approach can constitute a basis for the large-scale production of CNPs effective for widespread applications.
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