Molar concentration of silver nanoparticles on performance effect of surface-enhanced Raman scattering (SERS) glass substrate fabricated by drop-casting method

Abstract

This study investigated the effect of molar concentration of colloidal silver nanoparticles that enhanced Raman signal on Surface-Enhanced Raman Scattering (SERS) substrate performance. Colloidal silver nanoparticles were fabricated as SERS substrate on a glass microscope using drop-casting method. Colloidal silver nanoparticles have been synthesized separately in different concentrations of 5 x 10−4 M (sample 1) and 20 x 10−4 M (sample 2) from silver nitrate (AgNO3) irradiated by femtosecond laser in 5 minutes irradiation times. SERS substrates were fabricated on glass using a hot plate in around 100°C. The performance of SERS substrates was tested for the detection of 500 ppm deltamethrin pesticides using Raman spectroscopy. The result shows that there were increasing Raman signal in sample 2. This indicated that the increased molar concentration of colloidal silver nanoparticles enhances Raman signal. The samples were also characterized using FE SEM to know the particle size of nanoparticles in SERS substrate. Sample 2 that have a higher molar concentration of silver nanoparticles showed bigger particle size than sample 1. The particle size in sample 1 and 2 were 27.46 nm and 37.27 nm, respectively.