Peering into the Self- and Directed-Assembly of Nanoparticles

Self-assembly of synthetic nanoparticles enables the positioning of nanoparticles into one to three dimensional ordered arrays, facilitating integration of nanoparticle lattices into nanophotonic and nanoelectronic architectures. The functional properties of these particle materials are expected to be highly sensitive to structural factors such as coordination number, degree of long-range order, or interparticle separation distance, requiring the development of robust self- and directed-assembly pathways for precise control of structural parameters to improve optical and electronic properties of functional nanoparticles. In this presentation, I will review our past efforts in development of self-assembled nanoparticles thin film arrays and in-situ structural evolution at ambient condition. I will then extend my presentation to our recent progress in development of a new Stress-Induced Fabrication method in which we applied high pressure or stress to nanoparticle arrays to induce structural phase transition and to consolidate new nanomaterials with precisely controlled structures and tunable properties. By manipulating nanoparticle coupling through external pressure, a reversible change in their assemblies and properties can be achieved and demonstrated. In addition, over a certain threshold, the external pressure will force these nanoparticles into contact, thereby allowing the formation and consolidation of one- to three-dimensional nanostructures. Through stress induced nanoparticle assembly, materials engineering and synthesis become remarkably flexible without relying on traditional crystallization process where atoms/ions are locked in a specific crystal structure. Therefore, morphology or architecture can be readily tuned to produce desirable properties for practical applications.<br/><br/>Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.