Optical absorption study of the surface plasmon resonance in gold nanoparticles immobilized onto a gold substrate by self-assembly technique

The resonance wavelength of the surface plasmon in gold nanoparticles above a gold substrate has been measured using transmission absorption spectroscopy. Gold nanoparticles with diameters in the range of 20-100 nm are immobilized onto a thin gold film deposited onto a glass substrate by a self-assembled monolayer of aminoethanethiol. The resonance wavelength obtained in the experiments shows a large red shift. Its dependence on the particle diameter shows good agreement with theoretical results that are calculated using a static approximation that includes multipole effects.