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Abstract

The current paper provides an efficient method for making active and effectual substrates used for detecting molecules by improving surface-enhanced Raman scattering (SERS). These substrates were fabricated using nanostructure-coated porous silicon. The nanostructures were prepared through the electrical exploding wire (EEW) technique. The silver nanowires (AgNWs) were coated with a polydopamine (PDA) layer to form an AgNWs@PDA colloidal solution. Then, the Ag wire was electrically exploded in the colloidal solution to form the (AgNWs@PDA@AgNPs) plasmonic nanostructures as a metal-insulator-metal. The effect of the plasmonic nanostructures’ morphologies on the absorptances spectra and SERS activities were studied utilising Rhodamine 6G (Rh6G) dye as examination molecules. X-ray diffraction (XRD) was used to investigate the structural properties of these nanostructures. Field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were used to investigate the morphologies of these nanostructures. Atomic force microscopy (AFM) was used to study the surface topographies of SERS-effectual substrates. A double beam ՍV-Visible Spectrophotometer was used to measure Rh6G laser dye absorptance with a concentration of M) that mixed with the nanostructures at different concentrations. Sunshine Raman spectrometer with a (50 x) objective lens was used to analyse the Raman spectra of Rh6G Sunshine Raman spectrometer with a (50 x) objective lens was used to analyse the Raman spectra of Rh6G dye using a porous silicon substrate (PSi) on which silver nanowires are deposited (PSi-AgNWs). Another porous silicon substrate (PSi) on which nanostructures are deposited that consisting of silver nanowires, coated with a polydopamine layer, and decorated with silver nanoparticles are deposited (PSi-AgNWs@PDA@AgNPs). The results showed that hot spots and roughness on the nanostructures' surfaces caused an increase in intensities of absorptances spectra and signals of SERS. After the effectual substrates were excited by a (λexc.=532nm) laser source, the enhancement factor (EF) of SERS signals of Rh6G (1 M) attained (26.3 ) and (28.7 ) of the characteristic peaks at wavenumber (1650 ) for PSi-AgNWs and PSi-AgNWs@PⱰA@AgNPs effectual substrates respectively. This study showed that nanostructure-coated porous silicon substrates have a repeatable and high signal frequency, stability in storage, cost-low technique, and ease of use. They allow researchers to recognise and analyse a wide range of molecules, including biomolecules, with detection limits ranging between milli- and femtomolar. These effectual substrates have a bright future as a bioanalytical tool using SERS spectroscopy.

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This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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