Effect of Particle Material Composition

Material changes are typically the most trivial adjustment. Localized surface plas-mons can arise in particles made from all noble-metal types. As such, particles can be composed of any of the noble metals or from composites of two or more noble metals. Composite systems include alloy and heterodyne particles [58, 59]. 

In recent years, a variety of alloy and heterodyne particles have been developed. Nanocages are gold and silver alloy nanostructures that have a hollow interior and a thin, porous-but robust-wall [15]. By controlling the molar ratio of Ag to 

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