Metallic nanoparticles silver island films

Both Geddes and the Lakowicz group s have investigated the metal-enhanced fluorescence of fluorophores on silver island films (SIFs) [11,26,27] and variously aggregated silver nanoparticles in solution [28,29]. One example of enhancement on SIFs is discussed below [26]. In this work the distance-dependent MEF of a monolayer of sulforfiodamine B (SRB) on SIFs was studied. A SRB monolayer was electrostatically incorporated into the Langmuir-Blodgett (LB) layers of octadecylamine (ODA) deposited... 

In recent years we have been reporting our observations on the favorable effects of silver nanoparticles deposited randomly on glass substrates (silver island films) for increasing the intensities and photostability of fluorophores, particularly those with low quantum yields. These reports described fluorophores with visible excitation and emission wavelengths. Since the fluorophores interact with metal through die surface plasmon resonance, for-silver the absorption maximum is near 430 nm, we did not know if silver particles would enhance the emission of ICG with absorption and emission... 

Figure 3. Various type of SERS active metallic nanostructures (a) metal-island films (b) metal-coated nanospheres (semi-nanoshells) (c) metal-coated random nanostructures and (d) polymer coatings embedded with metal nanoparticles. Inset An SEM image of silver-coated polystyrene spheres.

Fig. 2 (Left) SEM images of silver vapor deposited on a ZnSe window with the nominal thickness measured with a quartz mierobalance the Ag islands are well separated in the 5-nm thick layer but are close to the pereolation limit in the 10-nm layer. (Right) SEIRA transmission spectra of PNTP for the 5-nm layer (dotted line) and the 10-nm layer (solid line). [In part reprinted from Band shapes in the infrared spectra of thin organic films on metal nanoparticles D. A. Heaps and P. R. Griffiths, Vibrational Spectrosc., 2006,42(1), 45-50 copyright 2006, with permission from Elsevier.]...

Silver, gold and copper are the most commonly used metals for SERS and the variety of substrates include, among others, roughened surfaces, nanoparticle colloidal suspensions, island films and nanostmctured surfaces (4). Current trends in SERS and Raman spectroscopy include the development of new substrates which includes immobilized particles, functionalized nanoparticles and nanolayered films. These recent development have created new opportunities for chemical and biological sensing. 

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