Surface Enhanced Raman Effect surfaces

Jackson J.B., Westcott S.L., Hirsch L.R., West J.L., Halas N.J., Controlling the surface enhanced Raman effect via the nanoshell geometry, Appl. Phys. Lett. 2003 82 257-259. 

SERS and SERRS, in particular, are well positioned for applications in the area of highly sensitive and specific biological and chemical detection. This is due primarily to emerging advances in nanotechnology and the development of miniature laser sources and light detection techniques. Two recent reports clearly point to the feasibility of developing sensors based on the surface-enhanced Raman effect. 

Vidugiris, G.J.A., Gudavicius, A.V., Razumas, V.J., and Kulys, J.J. (1989) Structure-potential dependence of adsorbed enzymes and amino adds revealed by the surface enhanced Raman effect European Biophysis Journal, 17, 19-23. 

Fig. 10.15 Raman spectrum demonstrating gold-coated AFM tip that causes a local surface-enhanced Raman effect on a sulfur film (A). When the beam is focused away...

Silver is an example of a metal that shows the surface-enhanced Raman effect. After a special surface treatment, the signal of a molecular group on the surface of the metal is enhanced by several orders of magnitude. One successful surface treatment is deposition of silver. So, after starting silver deposition from a cyanide electrolyte on a platinum electrode, a Raman signal of the CN-stretch vibration develops and reaches a limiting value (Figure 7.28). ... 

The Raman signal can be increased by increasing the Raman scattering cross section, a, and electromagnetic enhancement factor, T [13]. The a value can be increased by introducing the RR effect or surface enhancement Raman effect (the chemical effect), as already discussed. L... 

Despite the extensive studies of the anodic layers on Pt with various ultraviolet-visible optical methods, they have not provided a clear indication of the electronic or structural properties of the layers. Rather these optical methods have been more than just another form of readout to complement the electrochemical measurements of charge and current response of the layer to potential and time. Vibrational spectroscopic data from infrared and Raman measurements would be more helpful in establishing the nature of the layers but it is difficult to use these techniques to study metal-electrolyte and similar interfaces because of solvent interference and sensitivity problems. A noteworthy exception is the quite successful in situ use of Raman spectroscopy to study the electrochemically formed oxide layers on silver by Kotz and Yeager. In the instance of silver electrodes, there is a large surface enhanced Raman effect and the signal-to-noise ratio is not a problem. Unfortunately this is not the situation with other metal surfaces such as Pt. Even so, with improved instrumentation there is hope that in situ Raman studies of the anodic layers on Pt will become practical. 

Controlling the surface-enhanced Raman effect via the nanoshell geometry,i4pp/. Phys. Lett, 82, 257-259. 

SPECTROSCOPY OF POLYMER SURFACES USING THE SURFACE ENHANCED RAMAN EFFECT... 

The last problem of this series concerns femtosecond laser ablation from gold nanoparticles [87]. In this process, solid material transforms into a volatile phase initiated by rapid deposition of energy. This ablation is nonthermal in nature. Material ejection is induced by the enhancement of the electric field close to the curved nanoparticle surface. This ablation is achievable for laser excitation powers far below the onset of general catastrophic material deterioration, such as plasma formation or laser-induced explosive boiling. Anisotropy in the ablation pattern was observed. It coincides with a reduction of the surface barrier from water vaporization and particle melting. This effect limits any high-power manipulation of nanostructured surfaces such as surface-enhanced Raman measurements or plasmonics with femtosecond pulses. 

M. (2006) Ahgned silver nanorod arrays for surface-enhanced Raman scattering. Nanotechnology, 17, 2(>70-2(>74, (b) Lu, Y, Liu, G.L., Kim, J., Mejia, Y.X. and Lee, L.P. (2005) Nanophotonic crescent moon structures with sharp edge for ultrasensitive biomolecular detection by local electromagnetic field enhancement effect Nano Letters, 5, 119-124 ... 

STM-Raman spectroscopy utilizes the effect that Raman scattering is enhanced for a molecule in the vicinity of a metal nanostructure. This enhancement effect is generally called surface-enhanced Raman scattering (SERS). When a sharp scanning probe, such as a tunneling tip for STM, is used as a metal nanostructure to enhance Raman intensity, it is called tip-enhanced Raman scattering (TERS). The concept of STM combined with Raman spectroscopy is presented in Figure 1.1. 

Surface-enhanced Raman scattering (SERS) is a candidates for resolving this issue. Since the SERS effect is observed only at metal surfaces with nanosized curvature, this technique can also be used to investigate nanoscale morphological structures of metal surfaces. It is thus worth investigating SERS under oscillatory electrodeposition conditions. The author of this chapter and coworkers recently reported that... 

A large number of possible applications of arrays of nanoparticles on solid surfaces is reviewed in Refs. [23,24]. They include, for example, development of new (elect-ro)catalytical systems for applications as chemical sensors, biosensors or (bio)fuel cells, preparation of optical biosensors exploiting localized plasmonic effect or surface enhanced Raman scattering, development of single electron devices and electroluminescent structures and many other applications. 

Nevertheless, there has been a renewed interest in Raman techniques in the past two decades due to the discovery of the surface-enhanced Raman scattering (SERS) effect, which results from the adsorption of molecules on specially textured metallic surfaces. This large enhancement was first... 

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. 

The combination of surface enhanced Raman scattering (SERS) and infrared reflection absorption spectroscopy (IRRAS) provides an effective in-situ approach for studying the electrode-electrolyte interface. The extreme sensitivity to surface species of SERS is well known. By using polarization modulation of the infrared beam for IRRAS, the complete band shape is obtained without modulating the electrode potential. 

Effect of Underpotentially Deposited Lead on the Surface-Enhanced Raman Scattering of Interfacial Water at Silver Electrode Surfaces... 

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