Defects as Opportunities: Exploiting Atomic Interfaces and Nanostructures for Advanced Material Applications

Defects as Opportunities: Exploiting Atomic Interfaces and Nanostructures for Advanced Material Applications Precise interfaces at the atomic and electronic level
are highly sought after for various applications such as catalysis, separations, and electronics. Single atom dopants have proven effective in boosting the catalytic activity for numerous chemical reactions, while line defects have been instrumental in altering
the electronic properties of semiconductors. Additionally, disordered interfaces have shown promise in modulating the thermal conductivity of ceramics. Given the inherent thermodynamic and kinetic restrictions within a material system, the presence of
multiple phases and defects is unavoidable. However, it is important to note that not all defects are inherently detrimental to a material's performance. In fact, by comprehending the structural and electronic properties of defects and actively
controlling their prevalence, it is possible to create materials with enhanced performance. During this talk, I will present two studies that exemplify this approach:

1. I developed a comprehensive understanding of a porous MFI-zeolite membrane by employing various techniques. Firstly, through transmission electron microscopy (TEM) and automated pattern detection algorithms at the Å-scale, I discovered single-
unit-cell MEL defect patterns. Subsequently, at the nm-scale, I evaluated the pore deformations resulting from the diffusion of xylene molecules. Finally, at the cm-scale, I improved the membrane selectivity by incorporating rigid MEL defects for xylene
isomer separation (patent approved). [1,2]

2. I successfully created photonically active metasurfaces for light detection and ranging (LIDAR) devices through a series of steps. Beginning with the synthesis and characterization of nanostructured chiral microparticles, I achieved a widely tunable
bowtie shape spanning from the nm to the μm-scale. By arameterizing the correlations between the structure and its polarization rotation ability using chirality measures, I gained valuable insights for inverse design. Furthermore, I successfully scaled up the synthesis to gram-scale powders, enabling practical implementation (patent filed). 


[3] These studies serve as compelling demonstrations of the synergistic utilization of colloidal synthesis, transmission electron microscopy, chiroptical spectroscopy, and
continuum modeling techniques. Through their collective application, it becomes possible to fabricate materials with desired and controlled defects.

References
[1] Kumar, P. et al. One-dimensional intergrowths in two-dimensional zeolite nanosheets and their effect on ultra-selective transport. Nature Materials, 19, 443–449 (2020). 
[2] Kumar, P. et al. Quantification of thickness and wrinkling of exfoliated two-dimensional zeolite nanosheets. Nature Comms., 6, 7128 (2015). 
[3] Kumar, P. et al. Photonically active bowtie nanoassemblies with chirality continuum. Nature 615, 418–424 (2023) (Cover article).