Nanostructured metal particles, optical

Such optical nonlinearity arises in nanostructured metal particles as a consequence of the quantum confinement (4-6) of the particle s electron cloud. At... 

The success of the calculations depends mainly on the introduction of the nanostructural information into the calculation. At both routes of modeling, the nanostructural information can be introduced in different levels. In the first level, only the metal particle filling factor or a mean particle size is introduced. In the next level, also the particle shape is introduced. The best representation of the nanostructure can be reached by introducing the particle size and shape distribution or the size and shape of each single particle into the optical theory. 

Nanostructured clusters of semiconductors and metals, which differ from the corresponding bulk material due to surface, shape, and quantum size effects, have been designed to possess unique properties due to electron confinement. The unique properties of nanosized metal particles can be utilized in a broad range of fields, from catalysis to optical filters as well as nonlinear optical devices. To understand how nanoclusters can be combined with dendrimers, first let s summarize general properties of dendrimers. 

This chapter describes the synthesis, properties, and biomedical applications of cyanine and squaraine dyes encapsulated in CDs, CBs, Leigh-type tetralactam macrocycles, aptamers, and micro- or nano-particles. The optical and photochemical properties of supramolecular guest-host nanostructures that are based on intra-and intermolecular complexes of crown-containing styryl dyes with metal cations, and aggregates of carbocyanine dyes are discussed in a separate review [18]. 

Similar to zero-dimensional metal nanoparticles, most of the work on one-dimensional metal nanostructures focuses almost exclusively on gold nanorods. The high interest in anisometric gold nanoclusters arises from their unique optical and electronic properties that can be easily tuned through small changes in size, structure (e.g., the position, width, and intensity of the absorption band due to the longitudinal surface plasmon resonance is strongly influenced by the shell as well as the aspect ratio of the nanorods), shape (e.g., needle, round capped cylinder, or dog bone), and the inter-particle distance [157]. 

Metal nanostructures (such as particles and apertures) can permit local resonances in the optical properties. These local resonances are referred to as localized surface plasmons (LSPs). The simplest version of the LSP resonance comes for a spherical nanoparticle, where the electromagnetic phase-retardation can be neglected in the quasi-static approximation, so that the electric field inside the particle is uniform and given by the usual electrostatic solution [3] ... 

AmphiphiUc block copolymers self-assemble into a variety of supramolecular structures that can be used as templates for the preparation of nanoparticles and mesoporous materials. Size and shape of nanoparticles and mesopores can be controlled via block lengths and polymer concentration. Templates can be used for the preparation of noble metals, semiconductors, and ceramic nanostructures. Concepts of consecutive and hierarchical templating allow one to prepare complex nanostructures for applications in catalysis, electro-optics, and particle separation. 

For the comprehension of mechanisms involved in the appearance of novel properties in polymer-emhedded metal nanostructures, their characterization represents the fundamental starting point. The microstructural characterization of nanohllers and nanocomposite materials is performed mainly by transmission electron microscopy (TEM), large-angle X-ray diffraction (XRD), and optical spectroscopy (UV-Vis). These three techniques are very effective in determining particle morphology, crystal structure, composition, and particle size. 

In this chapter we discuss a novel approach to the concept of nanostructuring, which is based on coating metal or semiconductor nanoparticles with silica, so that the final morphology involves a silica sphere of the desired size containing a core placed precisely at its center. Although such concepts have been proposed before, it has only recently been possible to synthesize such coated materials in a reproducible manner. These composite spheres can then be used as the building blocks of the nanostructured material. The interest of these systems is due to the unique optical and electronic properties of nanosized metal and semiconductor particles. 

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