Chiral multiscale hierarchical materials

In this research my post-doc Haixiang Han and I along with team members, ask how we can structrally impart chirality into bulk materials starting from an atomic scale in a continuous, unbroken hierarchy. Chirality is essential to both quantum electronic/photonic/magnetic materials as well as fundamental biological building blocks. Our team (along with Curtis Williamson and Doug Nevers) discovered that it is possible to assemble achiral materials such as Our discovery structural and hierarchical manner irrespective of the chirality of the starting components. Our proposition and proof-of-concept is that,

Article

H. Han, S. Kallakuri et. al. “Multiscale hierarchical structures from a nanocluster mesophase” Nature Materials, volume 21, pages 518–525 (2022).

Spontaneous hierarchical self-organization of nanometre-scale subunits into higher-level complex structures is ubiquitous in nature. The creation of synthetic nanomaterials that mimic the self-organization of complex superstructures commonly seen in biomolecules has proved challenging due to the lack of biomolecule-like building blocks that feature versatile, programmable interactions to render structural complexity. In this study, highly aligned structures are obtained from an organic–inorganic mesophase composed of monodisperse Cd37S18 magic-size cluster building blocks. Impressively, structural alignment spans over six orders of magnitude in length scale: nanoscale magic-size clusters arrange into a hexagonal geometry organized inside micrometre-sized filaments; self-assembly of these filaments leads to fibres that then organize into uniform arrays of centimetre-scale bands with well-defined surface periodicity. Enhanced patterning can be achieved by controlling processing conditions, resulting in bullseye and ‘zigzag’ stacking patterns with periodicity in two directions. Overall, we demonstrate that colloidal nanomaterials can exhibit a high level of self-organization behaviour at macroscopic-length scales.

Article Publication Supplemental Information

5. Details of past work

5.1 Research @ Cornell

Advisors: Prof. Richard Robinson and Prof. Tobias Hanrath

My interests have led me to pursue an MS with thesis at Cornell advised by Prof. Richard Robinson & Prof. Tobias Hanrath where I developed ‘Multiscale hierarchical structures from nanocluster mesophases’. This work has been covered to great depth in our recent Nature Materials paper and in some news outlets that picked up on this work (Nature Press | Cornell News | Phys.org | Eurekalert | Technology.org | Newswise | Science News | Nanowerk | Science Springs | NanoTech Now). Super excited to see this platform realize it’s potential!

Hierarchy of self-assembly of our magic-sized cluster quantum-dot system. Images reprinted with permission from article journal and original authors. Citation: Nature Materials, 21(5): 518-525 (2022) : "Multiscale hierarchical structures from a nanocluster mesophase" H. Han, S. Kallakuri, Y. Yao, C. B. Williamson, D. R. Nevers, B. H. Savitzky, R. S. Skye, M. Xu, O. Voznyy, J. Dshemuchadse, L. F. Kourkoutis, S. J. Weinstein, T. Hanrath, R. D. Robinson

Link to MS thesis defense in case it is not viewable below: Here

Video: Final MS Thesis Defense at Cornell University on "Multiscale Hierarchical Structures from a Nanocluster Mesophase"

Optical, chiroptical, isomeric, and organizational properties of our MSC thin-films. Images reprinted with permission from article journal and original authors. Citation: Nature Materials, 21(5): 518-525 (2022) : "Multiscale hierarchical structures from a nanocluster mesophase" H. Han, S. Kallakuri, Y. Yao, C. B. Williamson, D. R. Nevers, B. H. Savitzky, R. S. Skye, M. Xu, O. Voznyy, J. Dshemuchadse, L. F. Kourkoutis, S. J. Weinstein, T. Hanrath, R. D. Robinson

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