Plasmon resonance band

Nanometals have interesting optical properties [37,73,74]. For example, suspensions of nanoscopic Au particles can be pink, purple, or blue depending on the diameter of the particles [74]. These colors arise from the plasmon resonance absorption of the nanometal particle, a phenomenon we have explored in some detail [37,73]. We have shown that membranes containing Au nanowires like those described here also show this plasmon resonance band, and as a result such membranes can show a wide variety of colors. This absorption in the visible region provides an interesting optical approach for characterizing the Au nanowire-containing membranes. 

The ability to prepare well-defined intradendrimer metal nanoclusters depends strongly on the chemical composition of the dendrimer. Spectroscopic results, such as those shown in Fig. 7, indicate that when G4-NH2, rather than the hydroxyl-terminated dendrimers just described, is used as the template a maximum of 36 Cu + ions are sorbed most of these bind to the terminal primary amine groups. Reduction of a solution containing 0.6 mmol/1 CUSO4 and 0.05 mmol/1 G4-NH2 results in a clearly observable plasmon resonance band at 570 nm (Fig. 11) [122,124,125] which indicates that the Cu clusters prepared in this way are larger than 4 nm in diameter. This larger size is a consequence of ag-... 

The simple route to prepare functional gold nanocages and their tunable surface plasmon resonance bands, which extend into the near-infrared, make these nanoobjects extremly interesting for biomedical applications. The synthesis, properties, and applications of gold nanocages has been reviewed.263... 

Fig. 4b. The longitudinal plasmon resonance band does not shift after the first few injections of MPA (point II), and shows significant shifts after 22 injections (point III). We assign the first step in the calorimetric data to the binding...

Cysteine ligands have also been reported in the synthesis of intricate copper nanoparticles following a literature modified reduction procedure. The Cu° nanoclusters revealed a plasmon resonance band at 398 nm and an average size distribution of 3.5 0.8nm by TEM. Infrared analysis of the stabilized nanoparticles showed a weakened S-H stretch at 2598 cm suggesting uncoordinated cysteine thiols, supporting the possible involvement of the amine functional group from the cysteine alpha carbon in particle stabilization. These particles displayed extreme O2 sensitivity, degrading under aerobic conditions to Cu (I) and then Cu (II) cysteine complexes. Additionally, this sensitivity precluded the convenient determination of nanoparticle crystallinity. ... 

In another study of Au°-(GSH), Wright etal. have synthesized nanoparticles in a completely aqueous media under anaerobic conditions. Following the standard reduction preparations with sodium borohydride, gold nanoparticles were produced with a plasmon resonance band at 512nm. Powder XRD analysis match a face-centered cubic lattice, while TEM showed that the particles had an average diameter of 4.5 1.2 nm. ... 

Zero-valent silver nanoparticles have also been synthesized using GSH as a surface passivant. Under standard reducing conditions, a preformed Ag(I)GSH complex was reduced to form nanoparticles of Ag -(GSH). After isolation and purification of the nanoclnsters, characterization showed a plasmon resonance band at 486 nm, a face-centered cnbic lattice structure revealed by powder XRD, and a particle diameter of 8.6 3.5 nm by TEM. ... 

Formation of zero-valent copper clusters with glutathione has been studied anaerobically. The ligand has been reported to provide a snbstantial degree of surface passivation. Rednction of a Cu(II)-GSH complex prodnced nanoparticles with a plasmon resonance band at 363 nm. These nanoparticles possessed a diameter of 9.7 4.3nm as demonstrated by TEM analysis. Under aerobic conditions, the nanoparticles oxidatively degrade as evinced by the loss of the plasmon absorption band over time. 

Miller, M. M. and Lazarides, A. A. (2006). Seiisitivity of metal nanoparticle plasmon resonance band position to the dielectric environment as observed in scattering. J. Opt. A Pure Appl. Opt. 8 S239-S249. 

This effect is depicted combining the SERS analysis with the microscopic investigation, as done in Fig. 20.12, where SEM images of Ag colloidal particles with adsorbed lH-1,2,3-triazole, deposited as dry layers onto cover glasses [22], are reported together with the SERS spectrum and the SPR (surface plasmon resonance) bands occurring in the UV-vis region. 

The produced intensity of the plasmon resonance band of silver nanoparticles essentially upraises and shifts down for lOnm (up to 410 nm). Hence, the presence of polymer that forms the stabilizing layer on silver nanoparticles and simultaneously reduces metal ions can provide the rise of electronic density of metal cores. This can increase the intensity of absorption band and shift it. The variation of silver ion / arabinogalactan ratios have shown a possibility to shift the plasmon absorption maximum [2]. This ratio in the range of 0.01-0.39 (g/g) leads to the increase of silver content from 1 to 19% in the composites accompanied by the absorption peak shift. 

Itoh, T., Asahi, T. and Masuhara, H. (2002) Direct Demonstration of environment-sensitive surface plasmon resonance band in single gold nanoparticles. Jpn. J. Appl. Phys., 41, L76-L78. 

Two types of Cu-nanoparticles-in-dielectric nanocomposites were produced through hydrogen reduction of Cu(II) Cu-zeolite and Cu-zeolite-silica. Amorphous silica was prepared by the sol-gel technique and served as optically transparent matrix incorporating zeolite microcrystals, The copper nanoparticles provide an optical response of the composite material due to the plasmon resonance band varied due to changes of matrix features. 

The two methods for synthesis of copper nanoparticles in dielectric matrices by the hydrogen reduction of copper ions are shown within the Cu-doped silica sol-gel films and the hybrid Cu-zeolite-silica sol-gel optical materials on transparent substrate. Presence of zeolite microcrystals witin sol-gel films gives more flexibility in variation of copper nanoparticle preparation. Optical features of copper nanoparticles in these systems are determined by their size and properties of surrounding medium and presented as the plasmon resonance band with different line profile. 

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