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Yiyu Cai (U Penn)

Date: Mon. August 29th, 2022, 12:45 pm-1:45 pm
Location: Rockefeller 221 (Foldy) & Zoom

Open- and close-packed oligomers via template-directed assembly of shape-engineered,
lithographically-fabricated nanoparticles

Yiyu Cai

Department of Electrical and Systems Engineering, University of Pennsylvania

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Abstract.—The top-down lithographic fabrication process can produce nanoparticles with well-defined sizes, shapes, and compositions that are not accessible synthetically. Using a template-assisted assembly technique, capillary forces drive the assembly of lithographically-fabricated nanoparticles into open or close-packed structures. The sizes and shapes of the templates control the coordination number, disorder, and location of defects such as voids in the nanoparticle assemblies. The optical properties of the assembled structures are characterized using dark-field scattering spectroscopy. Tunable Fano resonances are demonstrated in the spectra of pentagonal gold hexamers, showing dependence on the symmetry and interparticle distance. The multistep assembly method can co-assemble different types of nanoparticles into multi-material architectures. Semiconducting hexagonal germanium nanoparticle enhances the scattering of the surrounding triangular or square gold nanoparticles.

Host: Lydia Kisley 

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