Numerical investigation of the refractive index sensitivity of Au/Ag core-shell nanostructures for sensing applications

The plasmonic properties of bimetallic (gold and silver) core-shell nanostructures were studied numerically by using the boundary element method implemented in MATLAB (MNPBEM toolbox). dependence bulk refractive index sensitivity on core/shell thicknesses was investigated, regions enhanced sensitivities identified for both Ag@Au Au@Ag type nanostructures. For nanoparticles, utilizing a 14 ± 2 nm silver core radius with 4 gold shell thickness or 22 6 1 can yield 1.2–2.5× increase compared to purely nanosphere same size. structures, 20 3 size 10 found be optimal, enhancements between 5× pure nanoparticles increased always attributed hybridization plasmon absorbance peaks corresponding parts, which merging comes peak width (and thus decreased figure merit) as tradeoff. provided maps helpful design fabrication sensors