The Optical Properties of Copper Phthalocyanine Ultrathin Films Deposited on Silver: An ATR Study

Abstract

Ultrathin copper phthalocyanine adsorbate layers have been deposited onto silver films, and their optical properties in the visible spectral range have been investigated by angle-dependent attenuated total reflection measurements in Kretschmann-Raether prism coupler geometry. Down to an adsorbate mass coverage of 2 nm, the optical behaviour of the adsorbate is in accordance with the bulk optical constants of copper phthalocyanine. For thinner layers, the optical behaviour indicates an increase in the average absorption cross section of the copper phthalocyanine molecules at the silver surface. The effect may be explained as resulting from “hot spots” at the silver surface, originating from surface irregularities.