Optical Properties and Sensing Characteristics of Silver and Gold Nanoparticles: Size-Dependent Extinction Efficiencies

The presented manuscript studies extinction efficiencies ( Q ext ) essential for understanding the interaction between matter and electromagnetic waves, focusing on silver (AgNPs) and gold nanoparticles (AuNPs) for different nanoparticle sizes ranging from 10 to 60 nm and for two different surrounding mediums. For AgNPs, smaller sizes exhibit sharper plasmonic resonances, with a blue shift, while larger ones experience a redshift. Q ext increase with AgNP size. AuNPs show higher Q ext with size increase, with consistent full width at halfmaximum (FWHM). Both small and large AuNPs display sensitivity to refractive index (RI) changes, with AgNPs exhibiting greater sensitivity. The introduction of the figure of merit (FOM) highlights AgNPs’ good FOM values for smaller sizes and AuNPs’ enhanced sensitivity for larger sizes. This study underscores optical property differences, offering insights for diverse scientific and engineering applications.