Nanoparticle self-assembly as a model system for crystal growth and epitaxy

As the size of features in modern technological devices become increasingly smaller, the bottom-up approach to materials design is becoming more important. One class of materials for which bottom-up assembly is being actively studied is "soft" materials such as polymers, micelles, and nanoparticles. These materials are playing an increasingly important role in materials design and device fabrication, thus understanding the forces controlling their assembly is essential. Once the techniques are properly mastered and the driving forces are fully understood, the bottom-up assembly of "soft" materials will be a valuable tool for materials design.;In this thesis, nanoparticle self-assembly is utilized as a model system to study the crystallization of "soft" materials. This approach allows for differences and similarities in the behavior in hard and soft matter systems to be systematically explored. The size, shape, and composition of nanoparticles can be carefully tuned, allowing for the independent characterization of the different parameters. The effect of size on the crystallization behavior of nanoparticles is explored in Chapter 2 by examining the twinning probability in nanoparticle superlattices.;In Chapters 3-5, we study nanoparticle epitaxial growth by using self-assembled nanoparticle monolayers as substrates to control the self-assembly of deposited nanoparticles. This model system allows comparisons with atomic systems. Nanoparticle epitaxial growth has many similarities with traditional atomic systems; however, there are discrete differences between the systems due to the soft nature of the nanoparticles. These differences are explored and expanded upon by studying extreme lattice misfit and non-planar surfaces.;The physical (electronic and thermoelectric) properties of these systems are examined in Chapter 6. The role of nanoparticle size and composition on the thermal conductivity of nanoparticle arrays is studied in depth.;By understanding the factors that influence the physical properties and learning how to control their interactions, we will be able to synthesize and characterize novel materials with specifically engineered properties for use in electronic, optoelectronic, thermoelectric and photovoltaic applications.