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The structural characteristics and adsorption behavior of 4,4'-thiobenzenethiol (TBBT) self-assembled monolayers (SAMs) on Au is investigated by surface enhanced Raman scattering (SERS), electrochemical cyclic voltammetry (CV), ac impedance spectroscopy (EIS), and atomic force microscopy (AFM). A scanning electron microscopic image of Ag nanoparticles on TBBT/Au and the Raman spectrum of TBBT in smooth macroscopic Au/TBBT SAMs/Ag nanoparticle sandwich structure indicate that metal nanoparticles could be adsorbed on TBBT SAMs effectively through covalent linkage.

Sequential deprotonations of meso-(p-hydroxyphenyl)porphyrins (p-OHTPPH2) in DMF + H2O(V/V = 1:1) mixture are verified to result in the appearance of hyperporphyrin spectra. When the deprotonations are carried out the spectral changes differ considerably from those in the mixtures mentioned.

An effective and facile approach for the preparation of multilayered nanostructure of gold nanorods is demonstrated. The strategy presented here to construct three-dimensional nanostructure of Au nanorods (NRs) is quite facile and easy control, which opens up a routeway to the future application of Au NRs in nanodevices as well as in molecular detection.

Hydrothermal synthesis of multiple PDDA-protected (PDDA = poly(diallyl dimethylammonium) chloride) noble-metal nanostructures without any seed or surfactants is demonstrated. The nanostructures can be used as surface-enhanced Raman scattering substrates and can find applications in biosensors.

Two-dimensional (2-D) gold networks were spontaneously formed at the air−water interface after HAuCl4reacted with fructose at 90 °C in a sealed vessel, in a reaction in which fructose acted as both a reducing and a protecting agent. Through fine-tuning of the molar ratio of HAuCl4to fructose, the thus-formed 2-D gold networks can be changed from a coalesced pattern to an interconnected pattern. In the coalesced pattern, some well-defined single-crystalline gold plates at the micrometer-scale could be seen, while in the interconnected pattern, many sub-micrometer particles and some irregular gold plates instead of well-defined gold plates appeared. It is also found that the 2-D gold networks in the form of an interconnected pattern can be used as substrates for surface-enhanced Raman scattering (SERS) because of the strong localized electromagnetic field produced by the gaps between the neighboring particles in the 2-D gold networks. [ABSTRACT FROM AUTHOR]

Novel nanocomposite films containing DNA−silver nanohybrids have been successfully fabricated by combined use of the layer-by-layer self-assembly technique and an in situ electrochemical reduction method with the DNA−Agcomplex as one of the building blocks. UV−vis absorption spectroscopy was employed to monitor the buildup of the multilayer films, which suggested a progressive deposition with almost an equal amount of the DNA−Agcomplex in each cycle. The following electrochemical reduction of silver resulted in the formation of metal nanoparticles in the film, which was evidenced by the evolution of the intense plasmon absorption band originating from silver. Scanning electron microscopy indicated that the particles formed in the multilayer films possessed good monodispersity and stability, thanks to the surrounding polymers. X-ray photoelectron spectroscopy further confirmed the presence of the main components (such as DNA and metallic silver) of the nanocomposite films. In addition, we show that the size of the metal nanoparticles and the optical property of the film could be readily tuned by manipulating the assembly conditions. Furthermore, the feasibility of the as-prepared nanocomposite films functioning as a surface-enhanced Raman scattering active substrate for sensing purposes was investigated, and the results showed great enhancement of the Raman signal of two probe molecules, Rhodamine 6G and 4-aminothiophenol. [ABSTRACT FROM AUTHOR]