"Improving SERS substrates with Au/Ag‑coated Si nanostructures generated by laser ablation synthesis in PVA"

Abstract

"This paper provides an efficient approach for making effectual and active substrates utilized for the detection of the Pyrromethene 580 (PM 580) molecule through the improvement of surface-enhanced Raman scattering (SERS). Those substrates have been fabricated with the use of the Au/Ag nanoparticles-coated porous silicon (PS). Au/ Ag NPs have been prepared through laser ablation technique. This investigation is comparing Au/Ag NPs characteristics that have been generated by nanosecond laser ablation in PolyVinyl Alcohol (PVA) at 532 nm and 1064 nm laser wave-lengths. Then, Au/AgNPs were ablated in PVA colloidal solution to form (AuNPs:AgNPs)/PS plasmonic nanostructures. These plasmonic nanostructures on the SERS activities were studied utilizing PM 580 dye as examination molecule. Results have shown that the roughness and spots on nanostructures surfaces have resulted in causing increased absorbance spectra intensities and SERS signals. After effectual substrates have been excited by (λex. = 532 nm) laser source, the enhancement factor (EF) of SERS signals of PM 580 (0.01 M) attained 13.7 × 107 and 5.6 × 107 of the characteristic peaks at wavenumber 1657 cm−1 for the Au:AgNPs-532 nm/PS and Au:AgNPs-1064 nm/PS effectual substrates, respectively. The present research had shown that the nanostructure-coated PS substrates have repeatable and high signal frequency, inexpensive technique, stability in storage, and simplicity of use."