Nanotechnology
Abbas A. Thajeel; Mohammed A. Ibrahem; Duha S. Ahmed
Abstract
Nanoplasmonic sensing, based on the plasmonic resonance absorption of thin, irregularly-shaped Au nanostructures film, with a starting thickness of about 15 nm (±3 nm) sputtered on a quartz substrate, is used to monitor the CeO2 NPs (with an average diameter of 50 nm) film refractive index variations ...
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Nanoplasmonic sensing, based on the plasmonic resonance absorption of thin, irregularly-shaped Au nanostructures film, with a starting thickness of about 15 nm (±3 nm) sputtered on a quartz substrate, is used to monitor the CeO2 NPs (with an average diameter of 50 nm) film refractive index variations using different film thicknesses (90 nm, 146 nm, 172 nm, and 196 nm). Increasing the film thickness of solution-processed CeO2 NPs film, with layer-by-layer deposition on top of Au nanostructures, shows a significant redshift in the plasmonic resonance absorption of the plasmonic metal, from 580 nm to 611 nm. Such an increase is related to the change in the building microstructure of the semiconductor’s film which is reflected in changing its refractive index. Plasmonic surface refractive index sensitivity of 437.5 nm/RIU with FOM of 4.2 has been recorded. Such a sensing technique offers a large potential for developing cost-effective plasmonic nanosensing devices for clinical applications. This sensor structure is versatile and can be utilized to sense and monitor a large variety of materials and chemicals.
Zahraa Khedaer; Duha Ahmed; Selma Al-Jawad
Abstract
In this research, raw multiwalled carbon nanotubes (R-MWCNT) was successfully functionalized using sulfuric acid and nitric acid. Then a hybrid (ZnO-MWCNT) synthesized by the sol-gel method where diethylene glycol was used as a solvent and stabilizer that works to prevent the accumulation of nanoparticles ...
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In this research, raw multiwalled carbon nanotubes (R-MWCNT) was successfully functionalized using sulfuric acid and nitric acid. Then a hybrid (ZnO-MWCNT) synthesized by the sol-gel method where diethylene glycol was used as a solvent and stabilizer that works to prevent the accumulation of nanoparticles and reduces the viscosity of the solution. A group of diagnostic techniques, including XRD, UV-Vis, EDX and microscopy has recognized the structural and optical properties of the prepared nanoparticles. High Resolution Electronic Scanner (FE-SEM) was also used in the investigation. FE-SEM images showed the formation of the hybrid (ZnO-MWCNT) by the growth of spherical clusters on the surface of the cross-linked tubes (MWCNT). In addition, FE-SEM images confirmed the success of a ZnO-MWCNT hybrid. The emergence of spherical shapes deposited on cylindrical tubes and associated with a wrinkled surface was recognized. In addition, the particle size ratio increased. The UV-Vis spectra revealed that all the composites had good absorbency with a shift towards short wavelengths. While it was observed from the analysis of X-ray diffraction (XRD) the formation of a hexagonal wurtzite crystal structure due to zinc oxide with a polycrystalline nature. The average crystal size calculated from the Debye-spark equation increased with the increase in the concentration of the streaked material. Antibacterial activity was studied for all prepared samples against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) at different μg/ml concentrations (500, 750, and 1000). It was observed that the highest inhibition Zone for functionalized multiwalled carbon nanotubes (F-MWCNT) and ZnO-MWCNT hybrid was (17.3, 12.3mm), (22.5, 19mm) for Escherichia coli and Staphylococcus aureus, respectively.