12.2.2. Four-Wave Mixing (FWM) 4849 12.2.3. Dye Aggregation 4850 12.2.4. Optoelectronic Nanodevices 4850 12.3. Sensor 4851 12.3.1. Chemical Sensor 4851 12.3.2. Biological Sensor 4851 12.4. Catalysis 4852 13. Conclusion and Perspectives 4852 14. Abbreviations 4853 15. Acknowledgements 4854 16. References 4854 * Corresponding author E-mail: tpal@chem.iitkgp.ernet.in. † Raidighi College. § Indian Institute of Technology. 4797 Chem. Rev. 2007, 107, 4797−4862

Interparticle Coupling Effect on the Surface Plasmon Resonance of Gold Nanoparticles: From Theory to Applications

http://nathan.instras.com/ResearchProposalDB/doc-108.pdf

Radiative decay engineering 5: metal-enhanced fluorescence and plasmon emission

In the mid-1970s, surface-enhanced Raman scattering (SERS) was discovered which impacted on surface science and spectroscopy because of its extremely high surface sensitivity. However, SERS had not developed as many people had hoped to be a powerful surface diagnostic technique that can be widely used because of some obstacles. For example, only three noble metals Au, Ag, and Cu could provide large enhancement, severely limiting the widespread applications involving other metallic materials of both fundamental and practical importance. In this article, emphasis is put on the recent work of our group to directly generate SERS on net transition metals (e.g., Pt, Ru, Rh, Pd, Fe, Co, Ni, and their alloys) by developing various roughening procedures and optimizing the performance of the confocal Raman microscope. An approach of replacing the randomly roughened surface with ordered nanorod arrays of transition metals is introduced as a promising class of highly SERS-active substrates. The surface enhancement fa...

Surface-Enhanced Raman Scattering: From Noble to Transition Metals and from Rough Surfaces to Ordered Nanostructures

This Minireview systematically examines optical properties of silver nanoparticles as a function of size. Extinction, scattering, and absorption cross-sections and distance dependence of the local electromagnetic field, as well as the quadrupolar coupling of 2D assemblies of such particles are experimentally measured for a wide range of particle sizes. Such measurements were possible because of the development of a novel synthetic method for the size-controlled synthesis of chemically clean, highly crystalline silver nanoparticles of narrow size distribution. The method and its unique advantages are compared to other methods for synthesis of metal nanoparticles. Synthesis and properties of nanocomposite materials using these and other nanoparticles are also described. Important highlights in the history of the field of metal nanoparticles as well as an examination of the basic principles of plasmon resonances are included.

https://nathan.instras.com/ResearchProposalDB/doc-220.pdf

Synthesis and Optical Properties of Silver Nanoparticles and Arrays

Nanoparticles of noble metals belong to the most extensively studied colloidal systems in the field of nanoscience and nanotechnology. Due to continuing progress in the synthesis of nanoparticles with controlled morphologies, the exploration of unique morphology-dependent properties has gained momentum. Anisotropic features in nonspherical nanoparticles make them ideal candidates for enhanced chemical, catalytic, and local field related applications. Nonspherical plasmon resonant nanoparticles offer favorable properties for their use as analytical tools, or as diagnostic and therapeutic agents. This Review highlights morphology-dependent properties of nonspherical noble metal nanoparticles with a focus on localized surface plasmon resonance and local field enhancement, as well as their applications in various fields including Raman spectroscopy, fluorescence enhancement, analytics and sensing, photothermal therapy, (bio-)diagnostics, and imaging.

Properties and Applications of Colloidal Nonspherical Noble Metal Nanoparticles

Enhancement of the Raman scattering and fluorescence emission on noble metals (Ag, Cu, and Au) is believed to be caused in part by large local fields at the incident wavelength on the surface of metallic microstructures, such as colloidal suspensions and surface roughness on electrodes and thin films. For metallic spheres immersed in water, calculations are made of the integrated near-field intensity efficiency (${Q}_{\mathrm{NF}}$) and that part associated only with the radial field component as a function of incident wavelength (200- 1200 nm) and sphere radius (0- 300 nm) which exceeds the usual Rayleigh limit and extends well into the Lorenz-Mie region. The calculated wavelength and radius dependencies of ${\mathrm{Q}}_{\mathrm{NF}}$ are compared with those for the better-known efficiencies: extinction (${Q}_{\mathrm{E}}$), far-field scattering (${Q}_{\ifmmode\cdot\else\textperiodcentered\fi{}\mathrm{sca}}$), and absorption (${Q}_{\mathrm{abs}}$). The peak values of these efficiencies have been evaluated when the incident wavelength is in resonance with dipolar and multipolar surface-plasmon modes of Ag, Cu, and Au spheres of varying radii immersed in water.

K. Ulrich von Raben

Papers

Local fields at the surface of noble-metal microspheres

Voltage dependence of the pH at the interface of a Ag electrode: A SERS measurement of a phosphate-phosphoric acid system

SERS measurement of oxidation-reduction reactions of adsorbates on gold microstructures