Dynamics and Emergent Complexity in Functional Nanocrystals and Nanocrystal Superstructures

Friday, March 10, 2023 - 1:10pm
Event Type: 

Dr. Xingchen Ye, Indiana University (Bloomington)

Host: Dr. Huang

Functional materials built from nanocrystals and nanocrystal superstructures are enabling new applications in energy conversion and storage, optoelectronics, nanomedicine, among others. Essential to the realization of materials-by-design is to elucidate synthetic pathways and understand the kinetics of structural transitions. The process of nanocrystal assembly, analogous to a chemical reaction, usually traverses a complex free-energy landscape before reaching the final state. Therefore, we must begin to think of assembly as a reaction pathway connecting multiple nonequilibrium intermediates. Fully understanding these pathways requires real-space, real-time characterization with meaningful spatiotemporal resolution, which is not by possible with existing ex-situ characterization or scattering-based techniques. In the first part of this talk, I will discuss our recent advances on direct imaging of nanocrystal assembly using in-situ liquid cell transmission electron microscopy. The interaction potential between nanocrystals can be readily tuned by changing the solvent, which enabled observation and quantitative analysis of nonclassical crystallization pathways for nanocrystal superstructures. In the second part of this talk, I will introduce our work on creating shape-controlled dilute metal alloy nanocrystals by establishing distinct synthetic pathways during seeded-mediated growth. These well-defined nanocrystals are promising electrocatalysts for high-rate, selective conversion of chemical feedstocks into value-added products.

Dr. Xingchen Ye is currently an Assistant Professor in the Department of Chemistry at Indiana University Bloomington (IUB). Prior to joining IUB in 2017, he was a postdoctoral fellow at UC Berkeley working with Prof. Paul Alivisatos. He earned his PhD in Chemistry from University of Pennsylvania in 2012 under the tutelage of Prof. Christopher Murray and a B.S. in Chemistry from University of Science and Technology of China. Dr. Ye has received multiple research awards from the National Science Foundation (NSF) including the CAREER award and is a founding member of the recently established NSF Center for Single-Entity Nanochemistry and Nanocrystal Design (C-SENND). The Ye group focuses on precision synthesis of colloidal nanomaterials and their superstructures for energy applications as well as utilizing in-situ electron microscopy techniques to elucidate nanoscale dynamics and materials transformation.