Poulikakos Lisa V., Gutsche Philipp, McPeak Kevin M., Burger Sven, Niegemann Jens, Hafner Christian, Norris David J. (2016), Optical Chirality Flux as a Useful Far-Field Probe of Chiral Near Fields, in ACS Photonics
, 3(9), 1619-1625.
McPeak Kevin M., Jayanti Sriharsha V., Kress Stephan J. P., Meyer Stefan, Iotti Stelio, Rossinelli Aurelio, Norris David J. (2015), Plasmonic Films Can Easily Be Better: Rules and Recipes, in ACS Photonics
, 2(3), 326-333.
McPeak Kevin M., van Engers Christian D., Bianchi Sarah, Rossinelli Aurelio, Poulikakos Lisa V., Bernard Laetitia, Herrmann Sven, Kim David K., Burger Sven, Blome Mark, Jayanti Sriharsha V., Norris David J. (2015), Ultraviolet Plasmonic Chirality from Colloidal Aluminum Nanoparticles Exhibiting Charge-Selective Protein Detection, in Advanced Materials
, 27(40), 6244-6250.
McPeak Kevin M., van Engers Christian D., Blome Mark, Park Jong Hyuk, Burger Sven, Gosálvez Miguel A., Faridi Ava, Ries Yasmina R., Sahu Ayaskanta, Norris David J. (2014), Complex Chiral Colloids and Surfaces via High-Index Off-Cut Silicon, in Nano Letters
, 14(5), 2934-2940.
This project will fabricate and study inorganic colloidal particles that have a chiral shape. In general, an object is chiral if it cannot be superimposed on its mirror image. Colloids involve micrometer- to nanometer-scale solid particles that are dispersed in a solvent. Despite the importance of colloidal particles in many commercial products, it remains a fundamental challenge to prepare such particles that are chiral in shape. If they were available, they could exhibit many new and interesting chemical, transport, and optical properties. In particular, if made from plasmonic metals such as silver or gold, they should exhibit strong optical phenomena, including large circular dichroism. Consequently, they can have uses in many applications, such as catalysis, optics, sensing, and separations. In this project, a Ph.D. student and a postdoctoral researcher will investigate these materials. To prepare chiral particles, the team will use a completely new strategy that combines patterned silicon wafers with template stripping. Because of its simplicity, this approach should be able to provide chiral particles of many different shapes, sizes, and materials. The project will pursue particles that range in size from ~1 micrometer to ~50 nm. While gold will be the initial target material, many other inorganic solids, including metals, semiconductors, oxides, and their combinations will also be fabricated. Once prepared, the main goal of the research will be to gain fundamental understanding of the particles and their potential applications. This will include investigations of: (i) the optical properties of chiral colloidal dispersions, (ii) the binding of chiral molecules and their effect on optical properties, (iii) the transport of chiral particles or molecules through a channel packed with chiral particles, and (iv) the assembly of chiral particles into crystals or larger structures. For the optical properties, the team will also exploit the ability to perform complex electromagnetic simulations on the supercomputer at ETH Zurich and a collaboration with an analytical theorist who specializes in chiral particles. In addition to the training of a Ph.D student and a postdoctoral researcher, the expected outcome of the project is an understanding of how chiral particles can be prepared, their fundamental physical properties, and their potential applications. Preliminary experiments have already shown that the fabrication strategy should be able to provide many interesting materials.