A5082283852- Advanced Electron Microscopy Techniques and Applications
- nanoparticles nucleation surface interactions
- Quantum Dots Synthesis And Properties
- Catalytic Processes in Materials Science
- Electron and X-Ray Spectroscopy Techniques
- Material Dynamics and Properties
- Copper-based nanomaterials and applications
- Iron oxide chemistry and applications
- Electrocatalysts for Energy Conversion
- Force Microscopy Techniques and Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Chalcogenide Semiconductor Thin Films
- Ion-surface interactions and analysis
- 2D Materials and Applications
- Machine Learning in Materials Science
- Nanopore and Nanochannel Transport Studies
- Field-Flow Fractionation Techniques
- Graphene and Nanomaterials Applications
- Perovskite Materials and Applications
- Lipid Membrane Structure and Behavior
- Surface Chemistry and Catalysis
- Bone Tissue Engineering Materials
- Coagulation and Flocculation Studies
- Block Copolymer Self-Assembly
- Ecosystem dynamics and resilience
Seoul National University
2018-2025
Institute for Basic Science
2018-2025
Nonclassical features of crystallization in solution have been recently identified both experimentally and theoretically. In particular, an amorphous-phase-mediated pathway is found various systems as important route, different from the classical nucleation growth model. Here, we utilize high-resolution situ transmission electron microscopy with graphene liquid cells to study formation Ni nanocrystals. An amorphous phase precipitated initial stage reaction. Within particles, crystalline...
Abstract Ice crystals at low temperatures exhibit structural polymorphs including hexagonal ice, cubic or a hetero-crystalline mixture of the two phases. Despite significant implications structure-dependent roles mechanisms behind growths each polymorph have been difficult to access quantitatively. Using in-situ cryo-electron microscopy and computational ice-dynamics simulations, we directly observe crystalline ice growth in an amorphous film nanoscale thickness, which exhibits...
Unit-cell-thick MoS2 is a promising electrocatalyst for the hydrogen evolution reaction (HER) owing to its tunable catalytic activity, which determined based on energetics and molecular interactions of different types HER active sites. Kinetic responses sites, including onset, diffusion electrolyte H2 bubbles, continuation these processes, are important factors affecting activity . Investigating requires direct real-time analysis occurring spatially independent Herein, surface observed in...
Shape control is of key importance in utilizing the structure-property relationship nanocrystals. The high surface-to-volume ratio nanocrystals induces dynamic surface reactions on exposed facets nanocrystals, such as adsorption, desorption, and diffusion atoms, all which are important overall shape transformation. However, it difficult to track transformation understand underlying mechanism at level distinguishing events individual facets. Herein, we investigate changes surface-exposed...
Two-dimensional (2D) transition metal dichalcogenide (TMD) layers are unit-cell thick materials with tunable physical properties according to their size, morphology, and chemical composition. Their of lab-scale research industrial-scale applications requires process development for the wafer-scale growth scalable device fabrication. Herein, we report on a new type atmospheric pressure vapor deposition (APCVD) that utilizes colloidal nanoparticles as process-scalable precursors production TMD...
Abstract Over the last several decades, colloidal nanoparticles have evolved into a prominent class of building blocks for materials design. Important advances include synthesis uniform with tailored compositions and properties, precision construction intricate, higher-level structures from via self-assembly. Grasping modern complexity their superstructures requires fundamental understandings processes nanoparticle growth In situ liquid phase transmission electron microscopy (TEM) has...
Colloidal nanocrystals inherently undergo structural changes during chemical reactions. The robust structure-property relationships, originating from their nanoscale dimensions, underscore the significance of comprehending dynamic behavior in reactive media. Moreover, complexity and heterogeneity inherent atomic structures require tracking transitions individual at three-dimensional (3D) resolution. In this study, we introduce method time-resolved Brownian tomography to investigate temporal...
Transmission electron microscopy (TEM) is a crucial analysis method in materials science and structural biology, as it offers high spatiotemporal resolution for characterization reveals structure-property relationships dynamics at atomic molecular levels. Despite technical advancements EM, the nature of beam makes EM imaging inherently detrimental to even low-dose applications. We introduce SHINE, Self-supervised High-throughput Image denoising Neural network Electron microscopy,...
Defining the redox activity of different surface facets ceria nanocrystals is important for designing an efficient catalyst. Especially in liquid-phase reactions, where interactions are complicated, direct investigation a native environment required to understand facet-dependent properties. Using liquid cell TEM, we herein observed etching ceria-based under control redox-governing factors. Direct nanoscale observation reveals kinetics, thus identifying specific facet ({100} reduction and...
Uniformly dispersed palladium species in small-pore zeolite are successfully prepared for catalytic applications, and investigated by advanced microscopic methods.
Abstract Conformational changes in macromolecules significantly affect their functions and assembly into high‐level structures. Despite advances theoretical experimental studies, investigations the intrinsic conformational variations dynamic motions of single remain challenging. Here, liquid‐phase transmission electron microscopy enables real‐time tracking single‐chain polymers. Imaging linear polymers, synthetically dendronized with conjugated aromatic groups, organic solvent confined...
Liquid-phase transmission electron microscopy (TEM) offers a real-time microscopic observation of the nanometer scale for understanding underlying mechanisms growth, etching, and interactions colloidal nanoparticles. Despite such unique capability potential application in diverse fields analytical chemistry, liquid-phase TEM studies rely on information obtained from limited number observed events. In this work, novel liquid cell with large-scale array highly ordered nanochambers is...
Thermal motion and interactions of sub–4-nm particles are directly observed by graphene liquid cell electron microscopy.
The formation mechanism of colloidal nanoparticles is complex because significant nonclassical pathways coexist with the conventional nucleation and growth processes. Particularly, coalescence growing clusters determines final morphology crystallinity synthesized nanoparticles. However, experimental investigation a challenge process highly kinetic correlates surface ligands that dynamically modify energy interparticle interactions Here, we employ quantitative in situ TEM multichamber...
Colloidal nanoparticles are synthesized in a complex reaction mixture that has an inhomogeneous chemical environment induced by local phase separation of the medium. Nanoparticle syntheses based on micelles, emulsions, flow different fluids, injection ionic precursors organic solvents, and mixing metal with aqueous reducing agents well established. However, formation mechanism phase-separated medium is not understood because complexity originating from presence boundaries as nonuniform...
Colloidal nanoparticles are of great interest in modern science and industry. However, thermodynamic mechanism dynamics nanoparticle growth have yet to be understood. Addressing these issues, we tracked hundreds in-situ trajectories a ensemble using liquid-phase TEM discovered that the growth, including coalescence, exhibits size-dependent multiphasic dynamics, unexplainable by current theories. Motivated this finding, developed new model theory for an growing nanoparticles, providing...
Coalescence, one of the major pathways observed in growth nanoparticles, affects structural diversity synthesized nanoparticles terms sizes, shapes, and grain boundaries. As coalescence events occur transiently during are associated with interaction between mechanistic understanding is challenging. The ideal platform to study may require real-time tracking nanoparticle trajectories quantitative analysis for events. Herein, we track using liquid-cell transmission electron microscopy (LTEM)...
Colloidal nanoparticles are of great interest in modern science and industry, yet the thermodynamic origin nanoparticle formation remains a mystery growth frequently exhibits nonclassical dynamics. Here, we tracked hundreds in-situ trajectories ensemble using an advanced liquid-phase-TEM, discovered that growth, including coalescence, monomer supply rate dependent multiphasic dynamics, unexplainable by current theories. Motivated this finding, developed realistic model statistical theories...
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