Hydrophobic nanoparticle-based nanocomposite films using in situ ligand exchange layer-by-layer assembly and their nonvolatile memory applications

A robust method for preparing nanocomposite multilayers was developed to facilitate the assembly of well-defined hydrophobic nanoparticles (i.e., metal and transition metal oxide NPs) with a wide range of functionalities. The resulting multilayers were stable in both organic and aqueous media and were characterized by a high NP packing density. For example, inorganic NPs (including Ag, Au, Pd, Fe₃O₄, MnO₂, BaTiO ₃) dispersed in organic media were shown to undergo layer-by-layer assembly with amine-functionalized polymers to form nanocomposite multilayers while incurring minimal physical and chemical degradation of the inorganic NPs. In addition, the nanocomposite multilayer films formed onto flat and colloidal substrates could directly induce the adsorption of the electrostatically charged layers without the need for additional surface treatments. This approach is applicable to the preparation of electronic film devices, such as nonvolatile memory devices requiring a high memory performance (ON/OFF current ratio >10³ and good memory stability).