Honors & Awards
Stanford Interdisciplinary Graduate Fellowships, Stanford University (2019)
- Cathode-Electrolyte Interphase in Lithium Batteries Revealed by Cryogenic Electron Microscopy MATTER 2021; 4 (1)
- Unravelling Degradation Mechanisms and Atomic Structure of Organic-Inorganic Halide Perovskites by Cryo-EM JOULE 2019; 3 (11): 2854–66
Cryo-EM structures of atomic surfaces and host-guest chemistry in metal-organic frameworks.
2019; 1 (2): 428-438
Host-guest interactions govern the chemistry of a broad range of functional materials, but direct imaging using conventional transmission electron microscopy (TEM) has not been possible. This problem is exacerbated in metal-organic framework (MOF) materials, which are easily damaged by the electron beam. Here, we use cryogenic-electron microscopy (cryo-EM) to stabilize the host-guest structure and resolve the atomic surface of zeolitic imidazolate framework (ZIF-8) and its interaction with guest CO2 molecules. We image step-edge sites on the ZIF-8 surface that provides insight to its growth behavior. Furthermore, we observe two distinct binding sites for CO2 within the ZIF-8 pore, which are predicted by density functional theory (DFT) to be energetically favorable. This CO2 insertion induces an apparent ~3% lattice expansion along the <002> and <011> directions of the ZIF-8 unit cell. The ability to stabilize and preserve host-guest chemistry opens a rich materials space for scientific exploration and discovery using cryo-EM.
View details for DOI 10.1016/j.matt.2019.06.001
View details for PubMedID 34104881
View details for PubMedCentralID PMC8184120
Reduced propagation loss of surface plasmon polaritons on Ag nanowire-graphene hybrid
2018; 48: 197-201
View details for DOI 10.1016/j.nanoen.2018.03.045
Trends in mica-mica adhesion reflect the influence of molecular details on long-range dispersion forces underlying aggregation and coalignment.
Proceedings of the National Academy of Sciences of the United States of America
2017; 114 (29): 7537–42
Oriented attachment of nanocrystalline subunits is recognized as a common crystallization pathway that is closely related to formation of nanoparticle superlattices, mesocrystals, and other kinetically stabilized structures. Approaching particles have been observed to rotate to achieve coalignment while separated by nanometer-scale solvent layers. Little is known about the forces that drive coalignment, particularly in this "solvent-separated" regime. To obtain a mechanistic understanding of this process, we used atomic-force-microscopy-based dynamic force spectroscopy with tips fabricated from oriented mica to measure the adhesion forces between mica (001) surfaces in electrolyte solutions as a function of orientation, temperature, electrolyte type, and electrolyte concentration. The results reveal an ∼60° periodicity as well as a complex dependence on electrolyte concentration and temperature. A continuum model that considers the competition between electrostatic repulsion and van der Waals attraction, augmented by microscopic details that include surface separation, water structure, ion hydration, and charge regulation at the interface, qualitatively reproduces the observed trends and implies that dispersion forces are responsible for establishing coalignment in the solvent-separated state.
View details for PubMedID 28679632
View details for PubMedCentralID PMC5530655