Surface-enhanced Raman substrates

N. R. Jana and T. Pal, Anisotropic metal nanoparticles for use as surface-enhanced Raman substrates. Advanced Materials, 19(13), 1761-1765 (2007). 

S. (2008) Metal-decorated silica nanowires an active surface-enhanced Raman substrate for cancer biomarker detection. Journal of Physical Chemistry C, 112(6), 1729-34. 

SERS Surface-enhanced Raman spectroscopy [214-217] Same as RS but with roughened metal (usually silver) substrate Greatly enhanced intensity... 

Of special Interest as O2 reduction electrocatalysts are the transition metal macrocycles In the form of layers adsorptlvely attached, chemically bonded or simply physically deposited on an electrode substrate Some of these complexes catalyze the 4-electron reduction of O2 to H2O or 0H while others catalyze principally the 2-electron reduction to the peroxide and/or the peroxide elimination reactions. Various situ spectroscopic techniques have been used to examine the state of these transition metal macrocycle layers on carbon, graphite and metal substrates under various electrochemical conditions. These techniques have Included (a) visible reflectance spectroscopy (b) laser Raman spectroscopy, utilizing surface enhanced Raman scattering and resonant Raman and (c) Mossbauer spectroscopy. This paper will focus on principally the cobalt and Iron phthalocyanlnes and porphyrins. 

Possible applications include optical coatings [98], catalysts [99-101], substrates for Surface Enhanced Raman spectroscopy [102] or biosensor electrodes [103], Mesoporous gold can be prepared by de-aHoying a suitable precursor such as a... 

Ina similarmarmerto surface-enhanced Raman scattering, surface-enhancement of hyper-Raman scattering is a promising method to study adsorbed molecules on metal surfaces [24]. Based on recent developments in plasmonics, design and fabrication of metal substrates with high enhancement activities is now becoming possible [21]. Combination of the surface enhancement with the electronic resonances would also be helpful for the practical use of hyper-Raman spectroscopy. Development of enhanced hyper-Raman spectroscopy is awaited for the study of solid/liquid interfaces. 

Liu YC, Yang KH, Yang SJ (2006) Sonoelectrochemical synthesis of spike-like gold-silver alloy nanoparticles from bulk substrates and the application on surface-enhanced Raman scattering. Anal Chim Acta 572 290-294... 

Olson LG, Lo YS, Beebe TP Jr, Harris JM (2001) Characterization of silane-modified immobilized gold colloids as a substrate for surface-enhanced Raman spectroscopy. Anal Chem 73 4268-4276... 

Murphy T., Schmidt H., Kronfeldt H., Use of sol-gel techniques in the development of surface-enhanced Raman scattering (SERS) substrates suitable for in situ detection of chemicals in sea-water, Appl. Phys. B, 1999 69(2) 147-150. 

Tarabara V.V., Nabiev I.R., Feofanov A.V., Surface-enhanced Raman scattering (SERS) study of mercaptoethanol monolayer assemblies on silver citrate hydrosol. Preparation and characterization of modified hydrosol as a SERS-active substrate, Langmuir 1998 14 1092-1098. 

Goudonnet J.P., Begun G.M., Arakawa E.T., Surface-enhanced Raman-scattering on silver-coated Teflon sphere substrates, Chem. Phys. Lett. 1982 92 197-201. 

Alak A.M., Vo-Dinh T., Silver-coated famed silica as a substrate material for surface-enhanced Raman-scattering, Anal. Chem. 1989 61 656-660. 

Li Y.S., Vo-Dinh T., Stokes D.L., Yu W., Surface-enhanced Raman analysis of p-nitroaniline on vacuum evaporation and chemically deposited silver-coated alumina substrates,Appl. Spectrosc 1992 46 1354-1357. 

Li Y.S., Wang Y., Chemically prepared silver alumina substrate for surface- enhanced Raman-scattering, 4/ /)/. Spectrosc 1992 46 142-146. 

Vo-Dinh T., Meier M., Wokaun, A., Surface-enhanced Raman-spectrometry with silver particles on stochastic-post substrates. Anal. Chim. Acta 1986 181 139-148. 

Volkan M., Stokes D.L., Vo-Dihn T., Surface-enhanced Raman of dopamine and neurotransmitters using sol-gel substrates and polymer-coated fiber-optic probes, Appl. Spectrosc. 2000 54 1842-1848. 

Zhu T., Yu H.Z., Wang J., Wang Y.Q., Cai S.M., Liu Z.F., Two-dimensional surface enhanced Raman mapping of differently prepared gold substrates with an azobenzene self-assembled monolayer, Chem. Phys. Lett. 1997 265 334-340. 

Culha M., Stokes D., Allain L.R., Vo-Dinh T., Surface-enhanced Raman scattering substrate based on a self-assembled monolayer for use in gene diagnostics, Anal. Chem. 2003 75 6196-6201. 

The first electrodeposition of a compound superlattice appears to have been by Rajeshwar et al. [219], where layers of CdSe and ZnSe were alternately formed using codeposition in a flow system. That study was proof of concept, but resulted in a superlattice with a period significantly greater then would be expected to display quantum confinement effects. There have since been several reports of very thin superlattices formed using EC-ALE [152, 154, 163, 186], Surface enhanced Raman (SERS) was used to characterize a lattice formed from alternated layers of CdS and CdSe [163]. Photoelectrochemistry was used to characterize CdS/ZnS lattices [154, 186]. These EC-ALE formed superlattices were deposited by hand, the cycles involving manually dipping or rinsing the substrate in a sequence of solutions. 

Cation radicals of several metallated TPP and OEP complexes were reported to have unique IR active ring modes (21. These absorptions were observed in the region 1250-1290 cm for TPP complexes and 1520-1570 cm for OEP complexes. IR and raman active modes have also been observed for several different reduced oxygen species adsorbed on various metal substrates. Observations of the adsorption of oxygen on silver by surface enhanced raman spectroscopy (SERS) 22), show superoxide molecules (O2) have a frequency of 1053 cm, and peroxide (0 ) of 697 cm. This same study reported additional peaks were observed at 815 cm and 1286... 

An investigation of the adsorption of pyrazine and pyridine on nickel electrodes by in situ surface-enhanced Raman spectroscopy was reported in [44]. The result suggests that both pyrazine and pyridine were strongly adsorbed onto the substrates. It also implies that pyridine was adsorbed perpendicularly onto the substrate, while pyrazine adsorbed onto the substrate in a slightly tilted vertical configuration. 

The ILs interact with surfaces and electrodes [23-25], and many more studies have been done that what we can cite. As one example, in situ Fourier-transform infrared reflection absorption spectroscopy (FT-IRAS) has been utilized to study the molecular structure of the electrified interphase between a l-ethyl-3-methylimidazolium tetrafluoroborate [C2Qlm][BF4] liquid and gold substrates [26]. Similar results have been obtained by surface-enhanced Raman scattering (SERS) for [C4Cilm][PFg] adsorbed on silver [24,27] and quartz [28]. 

Another interesting photophysical property of Au NPs and nanorods is surface-enhanced Raman scattering (SERS), which is a powerful tool for relaying information on molecules placed on metallic substrates in the 10-200 nm size scale. Raman vibrations of isolated molecules are very weak but it is possible to take advantage of nanosized metals since the molecular Raman vibrations excited by visible light are enhanced by several orders of magnitude. 

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