Structure of CdS nanoparticles containing cadmium arachidate LB films

Abstract

Y-type cadmium arachidate LB films were exposed to H 2S gas for different durations. UV-VIS absorption spectra reveal an absorption edge at 455–460 nm in a 30 min H 2S exposed film which does not change appreciably on further exposure. The blue shifted absorption edge is attributed to the formation of 30 Å CdS nanoparticles. The H 2S exposed films exhibit two types of layered structures, that is, the original bilayer spacing of 55.2Å as well as an additional bilayer spacing of 44Å. The XRD peak intensities corresponding to the new bilayer spacing (44Å) increase up to 6h of H 2S exposure accompanied by an increase in bandgap absorption. These results suggest that CdS nanoparticles are formed within domains having tilted arachidate molecules distributed throughout the film without completely destroying the original layered structure of the LB film.