Novel synthetic methods, superlattice formation and nanomachining of gold nanoparticles

Nanomaterials, as an intermediate state between molecular and bulk matter, captivate the attention of researchers as a scientific wonder that allows the investigation of novel fundamental properties, as well as the creation of new advanced materials with numerous applications. The current dissertation research encompasses the field of gold nanoparticles and organized arrays composed of nanoparticles, known as nanocrystal superlattices. A major part of the work is devoted to the development of novel synthetic methods that allow the reproducible preparation of large amounts of high quality monodisperse metal nanoparticles. The ability to synthesize nanoparticles with a narrow size distribution in a reproducible fashion is an indispensable requirement for their application in practice.; Two completely different synthetic routes (a chemical method and a vaporization technique) are utilized in the current work. High-quality gold nanoparticles are reproducibly synthesized by both methods, and they behave as molecular crystals in the respect that they can be dissolved, precipitated, and redispersed without change in properties. Such particles have a strong propensity toward nanocrystal superlattice formation. A unique part of the study is the ability to control the core structure of the synthesized nanoparticles and hence to assemble them into superlattices with different structure. Different packing behavior results from differences in nanoparticle core morphologies induced by the synthetic method.; The prepared particles are stabilized by various molecules rendering them soluble in aqueous or non-aqueous solvents. The role of various factors such as the type of the stabilizing ligand, chain-length of the molecule, reaction temperature, and method for preparation on size, shape of the particles and superlattice formation is elucidated.; A noteworthy achievement of the work is the ability to manipulate the size, shape and morphology of the prepared nanoparticles by the use of specific molecules or a combination of molecules called 'nanomachines'. A diverse set of instrumental techniques is used for the characterization of both the nanoparticles and the nanocrystal superlattices.