|Nanocrystal Synthesis and Nanocrystal Superlattices |
Chemistry and Chemical Biology
|Stephen O’Brien, Columbia University|
11:00 AM, WL-Aud
Nanocrystals prepared by modern materials chemistry methods can be used as building blocks to form simple ordered arrays, called superlattices, which resemble the close-packed structures of atoms in crystals or hard spheres. The procedure can be described as a co-crystallization of nanocrystal dispersions following appropriate choice of solvents, substrates and conditions for self-assembly. The superlattices that result exhibit remarkable structural and compositional diversity, representing a variety of close packed structures reminiscent of binary alloy phases, and spanning a combination of magnetic and dielectric oxides, semiconductors and metals. The methodology can be thought of as a toolkit to assemble a wide range of structures intended for generating smart materials: thin films with enhanced functionality as a consequence of nanoscale manipulation. The mechanism of formation is a complex interplay of driving forces. We outline our efforts to synthesize a range of nanocrystals using a precursor decomposition process that can produce highly monodisperse samples. Such samples are prime candidates for superlattice assembly in the quest for control over structure and properties at the nanoscale.