Control of localized surface plasmon resonance energy in monolayer structures of gold and silver nanoparticles

Monolayer structures of Au and Ag nanoparticles (NPs) were fabricated by a dipping method to realize the control of localized surface plasmon resonance (LSPR) energy. The mean inter-particle distance in the monolayer was controlled by changing the concentration of NPs in the colloidal solution used for the monolayer assembly. The extinction-peak energy of the monolayer structure was red-shifted with decreasing inter-particle distance, reflecting plasmon coupling between NPs. The LSPR energy was successfully controlled in the wide range of 2.0-3.0 eV using Au and Ag nanoparticles.