Quantitative control and measurement of nanoparticle dynamics in liquid-phase transmission electron microscopy

Liquid-phase transmission electron microscopy (LP-TEM) has been widely used to study nanoparticle (NP) dynamics within liquid environments, facilitating investigation of particle diffusion dynamics during self-assembly process, and the morphological change of individual particles during etching and growth. However, the challenge of overcoming electron beam-induced effect and attaining more quantitative control and measurement remains a prominent obstacle in LP-TEM research. Throughout my Ph.D. studies, my research has been dedicated to advancing this frontier by integrating novel techniques and instruments. In the field of NP superlattice self-assembly, we envisioned the application of these structures in mechanical metamaterials. In Chapter 2, I pioneered the realization of nanoscale Maxwell lattice design through the self-assembly of gold nanocubes, leveraging LP-TEM to characterize the phonon vibration properties. This endeavor, supported by high-precision machine learning-based tracking algorithms, unveiled a quantitative agreement between experimental observation and theoretical predictions, holding the potential for inverse design of NP superlattice phononic properties. Furthermore, the soft phonons within the system are shown to be dictating the superlattice rearrangement dynamics and leads to intriguing size-dependent structural uniformity and dynamics in Chapter 3. In Chapter 4, we extended the design of the self-assembled building blocks to gold NPs with well-defined polymer patches. Here, LP-TEM studies of the patch-clasping bonding revealed the longitudinally robust and rotationally flexible nature, presenting promising avenues for metamaterials design. Shifting to NP growth dynamics, Chapter 5 introduced the integration between LP-TEM and novel four-dimensional scanning transmission electron microscopy (4D-STEM) in an in-situ manner, enabling concurrent characterization of real-space and reciprocal-space information during NP growth. This approach facilitated systematic exploration of growth inhibition effect, unveiling the nonclassical nucleation and phase transition during growth process. Finally, Chapter 6 summarizes the research findings and highlights future prospects for achieving more quantitative control and measurement capabilities in LP-TEM.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Materials Science & Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Qian, Chang

Contributors dc:contributor

• Chen, Qian
• Zuo, Jian-Min
• Schweizer, Kenneth S.
• Sing, Charles E.

• Nanoparticle
• Liquid-phase Tem
• Self-assembly
• 4d-stem

Statement dc:rights

• Copyright 2024 Chang Qian

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/125755

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F125755