Exploring Materials Synthesis, Structure and Dynamics: From in situ Electron Microscopy to 4D-STEM

Abstract: Precise structure control in materials synthesis is a long-standing pursuit to achieve designed material functionalities. One of the key challenges lies in understanding the nucleation and growth mechanisms during materials synthesis. The complexity and dynamic nature of nucleation and growth calls for the use of in situ techniques under synthesis conditions.

In this talk, I will present my work interrogating materials synthesis mechanisms by developing and applying in situ liquid-phase electron microscopy. I discovered a novel pathway of surface-induced nucleation and aggregation at the solid/liquid interface, providing a new avenue for the design and synthesis of those hierarchical materials. Furthermore, I also discovered a new dissolution process involving necking and particle detachment using the in situ microscopy technique.

I will then present the study of lithium nucleation and growth in lithium metal batteries by applying cryogenic electron microscopy. Finally, I will demonstrate a sub-unit-cell convergent beam electron diffraction method using a 4D-STEM approach to directly study electron density distribution and structural asymmetry. This method can be extended to study defects and interface in other electronic and quantum materials.

Bio: Guomin Zhu received his Ph.D. from the University of Washington. He was a research fellow at Pacific Northwest National Laboratory and is currently a Postdoctoral Associate in the Materials Department at the University of California, Santa Barbara.