Silver Nanotowers: Lift-Up Architecture and Plasmonic Applications

Plasmonic cuboidal Ag nanoparticles were grown vertically on a solid substrate by a seed-mediated growth method using Au nanospheres or nanocubes as growth seeds. Each nanocuboid, namely Ag nanotower, is grown at its bottom face, so that the seed is lifted up during the growth. Its size and aspect ratio can be controlled by changing seeds, growth time, and temperature. The nanotower shows different localized surface plasmon resonance (LSPR) modes including distal mode, proximal mode, a higher-order multipole mode, as well as a vertical mode. Higher order resonances tend to contribute to some of those modes for higher nanotowers. Intensity of some resonance modes depends on the incident angle of p-polarized light. Such structure with multiple plasmon modes would be applied to high-density data storage, polarizers, and nanoantenna ensembles for enhancement of Raman scattering, photovoltaics, and photocatalysis.