Assembly of CdS nanoparticles in patterned structures by a novel ion-entrapment process in thermally evaporated fatty acid films.

The formation of cadmium sulfide nanoparticle assemblies in a patterned manner on suitable substrates is described. The protocol for realizing such structures comprises the following steps. In the first step, patterned films of a fatty acid are thermally evaporated onto solid supports using suitable masks (e.g., a transmission electron microscope grid). Thereafter, the fatty acid film is immersed in cadmium sulfate solution and Cd2+ ions entrapped in the lipid matrix by electrostatic complexation with the carboxylate ions of the fatty acid molecules. The final step involves reaction of the entrapped Cd2+ ions with Na2S, leading to the in situ generation of cadmium sulfide nanoparticles within the patterned lipid matrix. This approach shows promise for generating patterned nanoparticle assemblies of different chemical compositions.