Enhancements in intensity and thermal stability of Raman spectra based on roughened gold substrates modified by underpotential deposition of silver
ABSTRACT In this study, electrochemically roughened gold is modified with underpotential deposition (UPD) silver to investigate the effects on enhancements in the intensity and the thermal stability of surface-enhanced Raman scattering (SERS). The SERS of Rhodamine 6G (R6G) adsorbed on the UPD Ag-modified Au substrate exhibits a higher intensity by six-fold of magnitude, as compared with that of R6G adsorbedon the unmodified Au substrate. Moreover, the SERS enhancement capabilities of UPD Ag-modified Au and unmodified Au substrates are seriously depressed at temperatures higher than 200 and 150 °C, respectively. It indicates that the modification of UPD Ag can significantly depress the thermal destruction of SERS-active substrates. Copyright © 2009 John Wiley & Sons, Ltd.
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ABSTRACT: The dephasing of particle plasmons is investigated using light-scattering spectroscopy on individual gold nanoparticles. We find a drastic reduction of the plasmon dephasing rate in nanorods as compared to small nanospheres due to a suppression of interband damping. The rods studied here also show very little radiation damping, due to their small volumes. These findings imply large local-field enhancement factors and relatively high light-scattering efficiencies, making metal nanorods extremely interesting for optical applications. Comparison with theory shows that pure dephasing and interface damping give negligible contributions to the total plasmon dephasing rate.Physical Review Letters 03/2002; 88(7):077402. · 7.94 Impact Factor
- Journal of Raman Spectroscopy 01/1998; 29(9):825-832. · 2.68 Impact Factor
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ABSTRACT: The formation of high-density silver nanoparticles and a novel method to precisely control the spacing between nanoparticles by temperature are demonstrated for a tunable surface enhanced Raman scattering substrates. The high-density nanoparticle thin film is accomplished by self-assembling through the Langmuir-Blodgett (LB) technique on a water surface and transferring the particle monolayer to a temperature-responsive polymer membrane. The temperature-responsive polymer membrane allows producing a dynamic surface enhanced Raman scattering substrate. The plasmon peak of the silver nanoparticle film red shifts up to 110 nm with increasing temperature. The high-density particle film serves as an excellent substrate for surface-enhanced Raman spectroscopy (SERS), and the scattering signal enhancement factor can be dynamically tuned by the thermally activated SERS substrate. The SERS spectra of Rhodamine 6G on a high-density silver particle film at various temperatures is characterized to demonstrate the tunable plasmon coupling between high-density nanoparticles.Nano Letters 02/2005; 5(1):5-9. · 13.03 Impact Factor