Electrophoretic Deposition of Multifunctional Nanoparticle Films

Even though the properties of individual nanoparticles are fascinating and technologically promising, to harness these properties, however, the particles need to be assembled in an array to form a superlattice. While there are ways of forming small ordered monolayers and crystals of nanoparticles there is no satisfactory method to deposit large areas of ordered multilayers films of nanoparticles. Dry casting and spin coating result in films that are typically not uniform and by nature, unpatterned. Multilayer, ordered and patterned films of nanoparticles are essential for device fabrication. We have developed a method to electrophoretically deposit nanoparticles to form multilayer films with remarkable topographical, optical, mechanical, and electrical properties. We have shown how the surface defects of nanoparticles can be used as an advantage to form almost defect free arrays with average roughness less than the diameter of the individual particles! Preliminary studies on the electrical, thermal, and mechanical properties of these films are reported.