Unraveling the Effects of Size, Composition, and Substrate on the Localized Surface Plasmon Resonance Frequencies of Gold and Silver Nanocubes: A Systematic Single-Particle Approach

Localized surface plasmon resonances (LSPRs), resulting from the interaction of light with metal nanoparticles, are powerful tools for biological sensors, surface-enhanced spectroscopies, and optical devices. LSPR frequencies are strongly dependent on a nanoparticle's structure, composition, and local dielectric environment. However, these relationships are prohibitively difficult or impossible to probe from bulk solutions due to the heterogeneity of chemically synthesized products. In this study, systematic single-particle structure−property measurements, coupled with a statistical analysis and FDTD calculations, are performed on silver and gold nanocubes. The dependencies of LSPR frequencies on nanocube size, composition, and substrate dielectric constant are determined. The results obtained represent the most quantitative measurements and analysis to date, yielding predictive rules and fundamental insights into the interactions between nanoparticles and substrates.