Tunable Plasmonic Response from Alkanethiolate-Stabilized Gold Nanoparticle Superlattices: Evidence of Near-Field Coupling

摘要

Noble metal nanoparticles exhibit a strong optical resonance phenomenon that is absent in the bulk phase. The related extinction band has been understood to be caused by a collective oscillation of conduction electrons in the nanoparticles under optical excitation and is characterized as the localized surface plasmon resonance (LSPR) band. Previous studies show that the LSPR band is sensitive to nanoparticle composition, size, shape, local dielectric environment, and electromagnetic coupling to other proximate nanoparticles. Recently, considerable attention has been given to the studies of coupled nanoparticle pairs as well as one-dimensional (1D) and two-dimensional (2D) nanoparticle arrays prepared by electron-beam lithography (EBL) because of their interesting and potentially useful collective plasmonic properties, which can be important in the emerging fields of plasmonics-based subwavelength optics.