IMX Seminar Series - Chiral Inorganic Nanostructures

Early observation of strong circular dichroism for individual nanoparticles and their assemblies have developed into a rapidly expanding field of chiral inorganic nanostructures. The chiral inorganic nanostructures encompass sophisticated constructs from metals, semiconductors, ceramics, and nanocarbons with multiple chiral geometries with characteristic scales from Ångströms to microns. Such versatility enables their functional engineering over a broad range of physical and chemical properties inspiring multiple technological realizations exemplified by biosensing and optoelectronics.   
This talk will address (1) the origin of the uniquely high values of optical anisotropy; (2) the mechanisms of chirality transfer in inorganic materials; and (3) differences/similarities with chiral supramolecular, liquid crystal, and biological assemblies.  The role of chiral inorganic nanostructures in homochirality of life on Earth will be briefly discussed. An essential role of long-range correlations and a possibility of critical phenomena in chiral nanoassemblies that lead to emergence of exceptionally complex structures will be demonstrated.  
Essential milestones toward utilization of chiral nanoscale assemblies in enantioselective catalysis and metaoptics will be outlined. One of the novel venues for practical realizations of chiral nanoassemblies include photocatalytic C-C coupling in biomimetic chiral supraparticles and CD spectroscopy in terahertz spectral window with chiroplasmonic kirigami composites.
References:
Kotov, N.A. Inorganic Nanoparticles as Protein Mimics Science, 2010, 330, 188.
 
Chen, W. et al. Nanoparticle Superstructures Made by PCR: Collective Interactions of Nanoparticles and a New Principle for Chiral Materials. Nano Lett. 2009, 9(5), 2153.
 
Srivastava, S.; et al Light-Controlled Self-Assembly of Semiconductor Nanoparticles into Twisted Ribbons. Science, 2010, 327, 1355–1359.
 
J.Yeom, et al Chiral Templating of Self-Assembling Nanostructures by Circularly Polarized Light, Nature Mater. 2015, 14, 66.
 
S. Jiang, et al.  Chiral Ceramic Nanoparticles of Tungsten Oxide and Peptide Catalysis, JACS, 2017, 139, 13701.
 
Yeom et al, Chiromagnetic Nanoparticles and Gels, Science. 2018, 359 (6372), 309-314.
 
W. Choi et al, Kirigami Modulators for Terahertz Chiroptical Spectroscopy, Nature Materials, 2019, 18, 820–826.
Bio: Prof. Nicholas A. Kotov is working on conceptual foundations and technical realizations of biomimetic nanostructures. In the course of his studies he demonstrated that self-organization is the unifying property of all nanoscale matter. Examples of biomimetic nanostructures associated with his works include graphite oxide,- graphene- and clay-based layered biomimetic nanocomposites, chiral nanomaterials, and omni-dispersible colloids.  His contribution to technology include ultrastrong nacre-mimetic nanocomposites, soft neuro-prosthetic implants, 3D tissue replicas for drug-testing, chiral biosensors, and cartilage-like electrolytes for batteries. Prof. Kotov is a founder of several start-up companies that commercialized bioinspired nanomaterials for biomedical, energy, and automotive technologies.