Nano-sized metal particles chemical properties

PHYSICAL AND CHEMICAL PROPERTIES OF NANO-SIZED METAL PARTICLES... 

Rao CNR, Kulkami GU, Thomas PJ, Agrawal W, Gautam UK, Ghosh M (2003b) Nanocrystals of metals, semiconductors and oxides novel synthesis and applications. Curr Sci 85 1041-1045 Rao CNR, Kulkami GU, Thomas PJ (2005) Physical and chemical properties of nano-sized metal particles. In Nicolais L, Carotenuto G (eds) Metal-polymer nanocomposites. WUey, Hoboken, New Jersey, pp 1-36... 

The investigation of the chemistry that occurs on the surface of colloidal metal particles is important for our imderstanding of many properties of nano-particles, such as their catalytic effects, their growth, and their electrochemical and photochemical behaviour. The electronics of nano-sized metal particles are changed when chemical events occur on the surface, and, consequently, certain physical properties such as their optical absorption are affected. On the other hand, optical measurements can often be used to trace the chemical modifications on the surface. 

The use of colloidal metallic nanoclusters deposited onto solid substrates can provide a higher degree of control over the SPs spectral properties state-of-the-art results in the chemical synthesis showed, in fact, the possibility to grow nano-objects with high uniformity and low size dispersion [36-38], This can allow to fabricate extended substrates, in which the local morphology, and thus the resulting MEF effect, can be controlled with good precision [19, 39], As a counterpart, still some randomness is unavoidable in this approach, since it is not simple to define the position of the nanoclusters on the substrate with micrometer precision to realize, for instance, ordered arrays of metallic particles. 

Metal colloids are assemblies of atoms with unique physical and chemical properties. These colloidal particles are nano-crystals or nano-amorphous lumps composed out of 2 to 10 atoms. which are bound together by crystal energy. Within the state of matter described by cluster-type behavior we define a nano-particle, nano-cluster, nano island, precipitate or- whatever name is used for these assemblies as a colloidal particle not specifying the size, shape or property of this assembly (Figure 1). 

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