Preparation of SERS-active gold film electrodes via electrocrystallization: their characterization and application with NIR excitation

The electrodeposition of a sufficiently large amount of gold on vapor-deposited film electrodes at high overpotentials leads to excellent substrates for surface-enhanced Raman scattering (SERS) spectroscopy. The SERS enhancement factor is estimated to be >10(7) with near-infrared excitation, a value which is superior to that for gold surfaces roughened by conventional oxidation-reduction cycles. Its wavelength dependence was studied over a wide range of excitation wavelengths and compared with that of silver electrodes prepared in an analogous manner. Furthermore, the broad applicability of the SERS-active gold film electrodes was demonstrated using numerous environmentally relevant s-triazine derivatives containing amino and/or thioether groups as probe molecules. Finally, it is shown that the high stability of the roughened gold surfaces allows even strongly adsorbed molecules to be removed by plasma cleaning without distinctly altering the SERS enhancement factor. First results allow the conclusion that this type of SERS-active surfaces is well suited for their repeated use. Copyright (C) 2004 John Wiley Sons, Ltd.