The manipulation of electrons, the smallest controllable charged particles, has advanced material engineering, especially as we navigate the intersection of classical and quantum limits. There is increasing interest in understanding the dynamic behaviors of electrons, whether free or bound within atoms, molecules, solids, or macro-scale devices, under a variety of operating conditions, including chemical and electronic reactions. To explore these phenomena, it is crucial to directly measure the electronic and chemical signatures that arise during such reactions to elucidate the interactions between electrons, spins, and lattices at fundamental lengths and timescales. In response to this need, we have developed a tabletop approach to transient extreme ultraviolet (XUV) absorption/reflection spectroscopy, integrated with gas-phase attosecond high-harmonic generation. The approach allows us to investigate the element-specific, real-time ultrafast dynamics of correlated electrons in the valence states of condensed matter when subjected to various external stimuli such as light, heat, or electrical currents. Additionally, we explore methods to tailor charged particles within the atomic layer interfaces of heterostructures in multilayered electronic devices and surfaces, the behaviors of ionic motions in both solid and liquid energy materials, and the mechanisms behind photoinduced energy conversion in solar energy systems. Our goal is to provide fundamental insights into these complex electronic processes from the perspective of physical chemistry.

• Ph.D. Physical Chemistry, UNIST, Republic of Korea, 2022 (Advisor
• M.S. Chemistry, UNIST, Republic of Korea, 2018 (Advisor
• B.S. Chemistry and Physics, UNIST, Republic of Korea, 2016

• Assistant Professor, Department of Chemistry, Seoul National University, Republic of Korea, 2024-Present
• Postdoctoral Scholar, Division of Chemistry and Chemical Engineering, California Institute of Technology, United States, 2022-2024 (Advisor: Prof. Scott K. Cushing)

1. “Coherent Charge Hopping Suppresses Photoexcited Small Polarons in ErFeO3 by Antiadiabatic Formation Mechanism”, Y.-J. Kim, J. L. Mendes, J. M. Michelsen, H. J. Shin, N. Lee, Y. J. Choi, S. K. Cushing, Sci. Adv. 2024, 10, adk4282.
2. “Femtosecond-Resolved Imaging of a Single-Particle Phase Transition in Energy-Filtered Ultrafast Electron Microscopy”, Y.-J. Kim, H.-W. Nho, S. Ji, H. Lee, H. Ko, J. Weissenrieder, O.-H. Kwon, , Sci. Adv. 2023, 9, eadd5375.
3. “Tailoring Two-Dimensional Matter Using Strong Light-Matter Interactions”, Y.-J. Kim, Y. Lee, W. J. Choi, M. Jang, K. Kim, Q-H. Park, O.-H. Kwon, Nano Lett. 23, 2023, 3645‒3652.
4. “Cathodoluminescence in Ultrafast Electron Microscopy”, Y.-J. Kim, O.-H. Kwon, ACS Nano 2021, 15, 19480‒19489.
5. “Light-Induced Anisotropic Morphological Dynamics of Black Phosphorus Membranes Visualized by Dark-Field Ultrafast Electron Microscopy”, Y.-J. Kim, Y. Lee, K. Kim, O.-H. Kwon, ACS Nano 2020, 14, 11383‒11393.
6. “Ultrafast Electron Microscopy Visualizes Acoustic Vibrations of Plasmonic Nanorods at the Interfaces”, Y.-J. Kim, H. Jung, S. W. Han, O.-H. Kwon, Matter 2019, 1, 481‒495.