Laser Science and Technology
Ruqaya Abdulkareem Shlaga; Alwan M. Alwan; Mohammed S. Mohammed
Abstract
In this work, several types of plasmonic sensors were prepared by different methods (ion reduction method and wet-chemical KOH route) to detect the ultralow anti-CIPRO concentration using AgNPs/PSi SERS-active substrate with AgNPs concentration. The process was optimized to be very effective in detecting ...
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In this work, several types of plasmonic sensors were prepared by different methods (ion reduction method and wet-chemical KOH route) to detect the ultralow anti-CIPRO concentration using AgNPs/PSi SERS-active substrate with AgNPs concentration. The process was optimized to be very effective in detecting CIPRO and to have a high amplification factor (EF). For the deposition of AgNPs with a concentration of 5×10-3 M and the maximum density of hotspot areas, a nanocrystalline silicon sample prepared by the KOH method and an ion reduction technique before etching was used. We tested an AgNPs/PSi SERS substrate, which showed better performance in detecting the CIPRO antibiotic over a range of doses (10-7-10-13 M). XRD, EDX, FESEM and SERS were used to analyze the PSi samples and the AgNP/PSi chemical sensors. The results of the AgNPs/PSi SERS substrates from both methods showed that the ion reduction process was more effective in detecting the CIPRO antibiotics at their lowest concentrations. It was found that the highest EF at salt concentrations of 5×10-3M was 6.3×1012 for the pre-etching method, compared with 7.78×1010 for the KOH method under the same conditions. The results showed that the proposed AgNPs/PSi SERS substrate is an effective method to find CIPRO even at low concentrations, and that CIPRO was localized approximately near the surface. This approach is considered a revolutionary work that has the potential to modify the plasmonic properties of metallic NPs for SERS applications.
Laser Science and Technology
Intisar A. Naseef; Alwan M. Alwan; Mehdi Q. Zayer; Layla A. Wali
Abstract
In scientific research, the search for cost-efficient and scalable functional materials for substantial and practical applications is necessary. Therefore, metallic materials at the nanoscale represent a rapidly growing area of research, especially as plasmonic materials in the field of surface-enhanced ...
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In scientific research, the search for cost-efficient and scalable functional materials for substantial and practical applications is necessary. Therefore, metallic materials at the nanoscale represent a rapidly growing area of research, especially as plasmonic materials in the field of surface-enhanced Raman scattering (SERS). In this study, the potential of copper nanowires (CuNWs) and palladium nanoparticles (PdNPs) as thin films on the porous silicon (PS) surface was investigated and compared. Their parameters as plasmonic SERS sensing materials were investigated by detecting sodium nitrite (NaNO2) molecules as the analyzing material. CuNWs and PdNPs were locally deposited on the PS substrate by the immersion method to synthesize Cu/PS and Pd/PS SERS sensors. The successful fabrication of these sensors was confirmed by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), and Raman measurements. The results show that the nanostructures of the metallic thin films are evenly distributed on the PS surface and that hot spot areas have formed in between. The Raman peaks of NaNO2 were effectively detected even at extremely low concentration values. Therefore, CuNWs and PdNPs were integrated with PS in the SERS to improve the detection process. Excellent detection of (5×10-6) M NaNO2 concentration was achieved with the Cu/PS and Pd/PS SERS sensors with high amplification factors of (0.43×108) and (0.11×108), respectively.
Laser Science and Technology
Rasha B. Rashid; Alwan M. Alwan; Mohammed S. Mohammed
Abstract
In this work, an investigation was conducted to study the effect of electrodes’ configuration of the double morphology macPSi on the performance of electrically matched impedance pesticides sensors. The purpose was to develop an efficient electrical sensor for the quantitative detection process ...
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In this work, an investigation was conducted to study the effect of electrodes’ configuration of the double morphology macPSi on the performance of electrically matched impedance pesticides sensors. The purpose was to develop an efficient electrical sensor for the quantitative detection process of (Chlorpyrifos) pesticide in organic solvents. The effect of electrodes configuration of the front, front-back, and back coplanar electrodes on macPSi as based substrate was tested to select an optimum sensor metallization pathway. The based efficient macPSi layer was fabricated using elevated laser irradiation power density at different periods. Morphological, optical, and electrical properties of the sensors were investigated using field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, and R-L-C measurement. The sensing method depended on measuring the resonance frequency shift as the organic solvent was exposed to the sensor’s surface. The sensor’s performance at various configurations and concentrations ppm was inspected at room temperature. The current findings revealed extremely low instabilities (less than 0.017 %), higher sensitivity, and a detection limit of 0.004ppm for top coplanar electrode configuration. The fabricated sensor is simple and low-cost for excellent quantitative pesticide detection.
