GOLD NANOPARTICLES FOR SEIRS
T. IGNAT, F. MAROUN, P. ALLONGUE

Abstract. An important application in the emerging field of plasmonics is the development of substrates capable of providing large electromagnetic enhancements for surface-enhanced spectroscopies. In this work, gold nanoislands were deposited on a semiconductor surface according to a special arrangement which increases the infrared sensitivity. The high sensitivity of surface enhanced infrared absorption allows the observation of changes in the chemical nature of the carboxyl head group of the 11- mercaptoundecanoic acid during pH changing. An analysis of the vibrational spectra suggests that by changing the pH, the carboxyl head group of the self assembled monolayer of thiol molecule can be deprotonated and re-protonated after adsorption without losing the adsorbed 11-mercatoundecanoic molecule.