Structure of CdS nanoparticles containing cadmium arachidate LB films

Y-type cadmium arachidate LB films were exposed to H2S gas for different durations. UV-VIS absorption spectra reveal an absorption edge at 455-460 nm in a 30 min H2S exposed him which does not change appreciably on further exposure, The blue shifted absorption edge is attributed to the formation of 30 Angstrom CdS nanoparticles. The H2S exposed films exhibit two types of layered structures, that is, the original bilayer spacing of 55.2 Angstrom as well as an additional bilayer spacing of 44 Angstrom. The XRD peak intensities corresponding to the new bilayer spacing (44 Angstrom) increase up to 6 h of H2S 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. Copyright (C) 1996 Elsevier Science Ltd