MSE Seminar: Brandi Cossairt (Washington)
Discovering New Ways to Make and Modify Quantum Dots: Pushing the Frontiers of Precision Structure and Function
We are interested in developing colloidal nanocrystals for applications in classical and quantum light technologies. Our approach leverages the extraordinary properties of nanoscale systems and applies foundational design principles from molecular inorganic chemistry. In this talk, we will examine strategies to overcome challenges in atomically precise synthesis and single particle placement by exploiting the extremes of nanocrystal size. First, the formation of kinetically persistent cluster molecules as intermediates in the nucleation of colloidal nanocrystals makes these materials of great interest for determining and controlling mechanisms of crystal growth. These clusters are also high-fidelity models for understanding the structure, bonding, and reactivity of larger nanocrystals, which are characterized by ensemble heterogeneity. The interconnection between structurally distinct members of these families, as well as their interconversion and conversion to larger nanocrystals, will be discussed. Next, producing scalable quantum photonics platforms using colloidal QDs as single-photon emitters is an outstanding challenge in quantum information science. We will explore two methods to exploit QD size to facilitate the deterministic positioning of single QDs into large arrays while maintaining their photostability and single-photon emission properties. Specifically, SiO2 and CdS shelling result in an increase in the QD physical size to allow precise positioning into ordered arrays using high-fidelity template-assisted self-assembly and electrohydrodynamic inkjet printing. We show that single “colossal” QDs before and after assembly exhibit antibunching behavior at room temperature and can be deterministically positioned on photonic cavities.
Bio:
Brandi Cossairt received her B.S. in chemistry from the California Institute of Technology in 2006 and her Ph.D. from the Massachusetts Institute of Technology in 2010. She then trained as an NIH NRSA Postdoctoral Fellow at Columbia University before joining the Department of Chemistry at the University of Washington in 2012. Her research group examines the nucleation, growth, surface chemistry, and reactivity of nanoscale materials to enable next-generation technologies in the diverse areas of displays, lighting, catalysis, quantum information, and hybrid matter.
