Seeding Bimetallic Nanostructures as a New Class of Plasmonic Colloids

Colloidal plasmonics is a rapidly developing field, with applications of metal nanoparticles that range from biosensing to photocatalysis. Historically, Au- or Ag-only nanoparticles have been investigated for these uses. However, there is emerging interest in multifunctional plasmonic colloids as well as a desire to expand the light scattering and absorption properties of Au or Ag nanoparticles. Both of these goals can be achieved by incorporating a second metal. In this Perspective, recent advances in the synthesis and application of Au-Ag and Au-Pd nanostructures are discussed. The highlighted nanostructures were synthesized through the seed-mediated method, an approach that provides for structurally complex nanoarchitectures while maintaining sample homogeneity. Overall, these architecturally controlled bimetallic nanostructures are representative of a new class of plasmonic colloids in which composition and structure can be manipulated to achieve unique optical properties and functionality.