Laser ablation synthesis in liquid solution (PLAL) is a green technique that allows for the physical formation of nanomaterials. This study indicates the preparation of stable gold nanoparticles (AuNPs) in Gum Arabic (GA) solution via laser ablation as a CT contrast agent. The optical properties were achieved using the absorption spectroscopic technique whereas the morphology and size distribution were investigated by TEM and ImageJ software. TEM image shows greater stability and spherical shape of GA-AuNPs with smaller size at 1.85 ± 0.99 nm compared to AuNPs without GA. The absorption spectrum of pure AuNPs has a lower absorption peak height in the visible range at λ = 521 nm, while the spectrum of GA-AuNPs has a higher plasmon peak height at λ = 514 nm with a blue shift towards lower wavelengths. The concentration of GA that dissolved in 10 mL of DI water via laser ablation is set at 20 mg. Increasing the number of pulses has only a minor effect on particle size distribution, which remains tiny in the nanometer range (less than 3 nm). For energies greater than 200 mJ, there is a blue shift toward shorter wavelengths. As the concentration of GA-AuNPs increases, the CT number is also increased indicating good image contrast. It can be concluded that there is a positive and significant influence of GA as a reducing agent for AuNPs, and a contrast agent for CT imaging which highlights its superiority in future medical applications.

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In the present work, gold nanoparticles (Au NPs) were synthesized on indium tin oxide (ITO) thin film on glass substrate for the pH sensing application based on extended gate field effect transistor (EGFET). The ITO thin film was deposited on glass using RF sputtering and then the Au NPs were synthesized on it by pulsed laser ablation in liquid (PLAL) technique. The Au NPs were characterized using transmission electron microscope (TEM), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopic techniques. From the TEM analysis, the size of the spherical shaped Au NPs was found to be in the range of 5-22 nm. The UV-Vis spectroscopy analysis revealed absorption peak at 518 nm, indicating purplish red color. The XPS data revealed Au 4f doublet binding energy peaks of the photoelectrons at 83.79 and 87.45 eV. The currentvoltage (I-V) curves indicated pH sensitivities values of 43.6 mV/pH and 0.6 (𝜇𝐴) 1 2 /𝑝𝐻 with linear regression of 0.9. The hysteresis and drift characteristics of Au NPs/ITO/G membrane were also studied to investigate its stability and reliability. The results of this work demonstrated that the Au NPs/ITO/G membrane is quite useful for the acidity and basicity detection.

A novel chalcone based pyrene (E)-1-(4-(1H-imidazol-1-yl)phenyl)-3-(1,5a1-dihydropyren-1-yl)prop-2-en-1-one (EIPDP) has been successfully synthesized by Claisen-Schmidt condensation reaction. The molecular structure was optimized using density functional theory (DFT) at B3LYP/ 6-311++G(d,p) basis set. In addition, molecular electrostatic potential (MEP) was obtained to study the intramolecular charge transfer (ICT) by introducing electrophilic and nucleophilic sites on the compound surfaces. Absorption UV-Vis spectra were performed experimentally and theoretically to study the electron transitions of the EIPDP. Further, the excitation states were characterized using the hybrid exchange-correlation functional of Coulomb Attenuated Method-Becke, 3-parameter, Lee-Yang-Parr (CAM-B3LYP) with the Integral Equation Formalism Polarizable Continuum Model (IEFPCM) in Dimethyl sulfoxide (DMSO) solvent at the same basis set. The nonlinear optical (NLO) properties were investigated using Z-scan techniques with continuous wave (CW) laser at 630nm. The NLO findings disclosed that the third-order nonlinear optical parameter (χ 3) for the title compound is in the order of 10−6 esu.