Enhanced and Tunable Optical Quantum Efficiencies from Plasmon Bandwidth Engineering in Bimetallic CoAg Nanoparticles (Open Access Publisher's Version)
Journal Article - Open Access
TENNESSEE UNIV KNOXVILLE KNOXVILLE United States
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Plasmonic nanoparticles are amongst the most effective ways to resonantly couple optical energy into and out of nanometer sized volumes. However, controlling andor tuning the transfer of this incident energy to the surrounding near and far field is one of the most interesting challenges in this area. Due to the dielectric properties of metallic silver Ag, its nanoparticles have amongst the highest radiative quantum efficiencies, i.e., the ability to radiatively transfer the incident energy to the surrounding. Here we report the discovery that bimetallic nanoparticles of Ag made with immiscible and plasmonically weak Co metal can show comparable andor even higher values. The enhancement is a result of the narrowing of the plasmon bandwidth from the sebimetal systems. The phenomenological explanation of this effect based on the dipolar approximation points to the reduction in radiative losses within the Ag nanoparticles when in contact with cobalt. This is also supported by a model of coupling between poor and good conductors based on the surface to volume ratio. This study presents a new type of bandwidth engineering, one based on using bimetal nanostructures, to tune andor enhance the quality factor and quantum efficiency for near and far-field plasmonic applications.
- Plasma Physics and Magnetohydrodynamics