The effect of thin organic films on the surface plasma resonance on gold

Abstract

Optical constants of organic monolayers on gold are calculated from shifts in the surface plasmon resonance. Two to several organized layers of cadmium arachidate (each known independently to be 2.68 nm thick) were deposited onto gold films. The angle of minimum attenuated total reflectance changed by about 0.5 degree, corresponding to a Δ k sp of approximately 900 cm -1 for each additional monolayer. Because of the large angular shifts and the simplicity of the ATR method, this technique appears to be an easy and accurate way to determine optical constants and monitor changes in thin (order of nm) interfacial layers on metals.