Event
MSE Seminar: Dr. Guomin Zhu, UCSB
Thursday, March 14, 2024
11:30 a.m.-12:30 p.m.
Room 2460 A.V. Williams Bldg.
Sherri Tatum
301 405 5240
statum12@umd.edu
Illuminating Crystallization Pathways by Electron Microscopy
Abstract: Numerous lines of evidence are challenging the traditional picture of crystallization by atomic attachment. Several alternative crystallization pathways involving particle attachment are proposed. The nuances of these crystallization pathways make it very challenging to elucidate the crystallization pathway[1].
In this talk, I will present my work on the elucidation of the crystallization mechanism for hematite mesocrystals, a class of hierarchical materials composed of crystallographically aligned nanocrystals as building blocks using in situ liquid phase transmission electron microscopy (TEM). I discovered a novel pathway of surface-induced nucleation and aggregation, which is changing paradigms for the growth of those hierarchical materials and how nucleation occurs at the solid/liquid interface[2]. I further applied this technique to uncover the dissolution dynamics of hematite. A previously unknown dissolution pathway which involves necking and particle detachment is uncovered. In situ liquid cell TEM is a state-of-the-art technique for studying the dynamics of chemical transformation in liquid at the atomic scale[3]. I will present the study of lithium nucleation and growth in lithium metal batteries by developing and applying cryogenic TEM techniques. Finally, I will present my work on developing and applying advanced scanning transmission electron microscopy (STEM) to study antiferrodistortive and ferroelectric orders in the strontium titanate system[4]. All these research efforts will be tied together in my vision for developing and applying electron microscopy to understand and develop materials systems that will transform areas in materials synthesis, energy conversion and storage, and quantum materials.
Reference.
[1] Science 349.6247 (2015): aaa6760. [2] Nature 590.7846 (2021): 416-422. [3] Nature Communications 14.1 (2023): 6300. [4] Under Review.
Bio: Dr. Guomin Zhu is currently a Postdoctoral Associate in the Materials Department at the University of California, Santa Barbara (UCSB), where he works with Prof. Susanne Stemmer. He was a postdoctoral scholar at the University of California, San Diego (UCSD) in 2021-2022, working with Prof. Shirley Meng. His broad research interest lies in studying dynamics of materials transformation (e.g., nucleation and growth, phase transformation, order characterization) for materials synthesis, energy conversion and storage, and quantum materials by developing and applying advanced electron microscopy tools and methods (e.g., in situ liquid cell electron microscopy, cryogenic electron microscopy, 4D-STEM).
Guomin received his Ph.D. in Materials Science and Engineering in 2020 from the University of Washington, under the supervision of Prof. James De Yoreo. He was a research fellow at Pacific Northwest National Laboratory (PNNL) from 2018 to 2020.
