Diversifying the Chemistry of Covalent Organic Frameworks (COFs): From 1D Ribbons to 2D Frameworks and Entanglement of 2D Square Nets
Covalent organic frameworks (COFs) are extended structures that are composed of solely organic building units stitching together through strong bonds. Within the realm of COF chemistry, 1D infinite structures are rarely studied; 2D structures are often constructed by the combination of planar linking units facilitated by π−π stacking; and the vast majority of 3D frameworks are made up of nonplanar units. To advance our understanding of COFs, this seminar explores their chemistry from 1D ribbons to 2D frameworks, with a specific focus on the entanglement of 2D square nets to 3D structures using combinations of planar linking units. By diversifying the structural chemistry of COFs, we aim to unlock their variable structures and properties for future innovative applications in materials research.
Dr. Nguyen obtained his Ph.D. from the University of Technology, Vietnam National University at Ho Chi Minh City (Vietnam) in 2017. He spent almost a year working at King Fahd University of Petroleum and Minerals (Saudi Arabia) as a Research Consultant before joining the group of Prof. Omar Yaghi at the University of California Berkeley where he is currently an Assistant Project Scientist. Dr. Nguyen’s research interest centers around the design and synthesis of novel framework structures (metal–organic frameworks and covalent organic frameworks) for water harvesting, carbon capture, and conversion. He was listed in the top 2% of scientists in his field identified by Stanford University in three successive years 2020, 2021, and 2022.
Visualizing Spin-Valley Drift Current in WS2/WSe2 Heterostructures
Transition metal dichalcogenides (TMDCs) materials hold promise for spintronic and valleytronic applications due to their ability to generate and control valley-polarized excitations using circularly polarized photons. In this work, we demonstrate efficient generation of a locked spin-valley drift current in a WS2/WSe2 heterostructure by applying an in-plane electric field enabled by α-RuCl3 hole doping in the contact regions. We show that electrostatic gating and in-plane field manipulation allow precise control of the valley drift current, offering potential applications in valleytronics.
Jingxu is a Ph.D. candidate in the Department of Physics at UC Berkeley and in the Lawrence Berkeley National Laboratory working with Prof. Feng Wang. His research focus includes light-matter interactions and electrical transport in condensed matter physics, with an emphasis on novel quantum phenomena emerging in low-dimensional materials.