Wed, 10/30/2019 - 4:10pm to 5:00pm
DeMeritt 240
Material Science Seminar
Dr. Ou Chen, Brown University

Self-assembly of anisotropic nanocrystals from periodic superlattices to aperiodic quasicrystals

Colloidal nanocrystals have been widely studied for decades. Continuous optimizations in synthesis have allowed the production of quantum dots and other nanocrystals with exquisitely controlled size, shape, composition and surface state. Analogous to atoms/molecules, these high-quality nanocrystals can be used as artificial building blocks for constructing higher-order architectures that are relevant to various of applications. While building assemblies from isotropic nanoparticles has been well studied and documented, creating novel superstructures from the nanocrystals with anisotropic factors still lags significantly behind. When utilizing in assembly, anisotropic nanocrystals can display strong asymmetric interactions induced by their anisotropic patchiness, which may complicate the formation of ordered structures compared to the assemblies of isotropic building blocks. In this talk, I will use several types of anisotropic 'patchy' quantum dot-based nanocrystals created in my lab as examples to demonstrate how they assemble into unprecedented superstructures through directional interactions among the building blocks. Both translational periodicities and orientational ordering of the final superstructural materials will be discussed. The dominating driving forces lead to the obtained architectures will be discussed and identified through both experimental results and molecular dynamics computer simulations.