Synthesis of Spherical Gold Nanoparticles and Enhancement of Dye Absorption in Solution by SEVA

Gold nanoparticles (Au-NPs) synthesised in water were transferred into an organic solvent and mixed with the azo dye Disperse Red 1 (DR1) at varying concentrations. UV–Vis spectroscopy revealed a pronounced Surface-Enhanced Visible Absorption (SEVA) effect driven by localised surface plasmon resonance. This work advances fundamental understanding of light–matter interactions at the nanoscale and opens pathways for ultrasensitive molecular detection, plasmonic photothermal therapy for cancer treatment, and next-generation sensing technologies.