The Department of Chemical Engineering is pleased to virtually host Dr. Delia Milliron, Professor & Department Chair of Chemical Engineering at University of Texas at Austin, on Thursday, January 20 at 10:35am to present her virtual seminar titled “Assemblies of doped metal oxide nanocrystals.”
ABSTRACT
Metal oxide nanocrystals doped with a few percent of aliovalent dopants become metallic and support strong light-matter interactions in the infrared due to localized surface plasmon resonance (LSPR). The incredible tunability of the prototypical material, tin-doped indium oxide (ITO) has made ITO nanocrystals versatile building blocks for both electronic and optical materials. In these assemblies, macroscopically observable properties like conductivity and optical absorption depend on both the properties of the nanocrystals themselves and on coupling between nanocrystals. In densely packed thin films, I will show how conductivity and even the mechanism for electron transport is controlled systematically varying the conductance of contacts between neighboring nanocrystals. Nanocrystal gels are porous, percolating structures that can in principle lead to tunable (valence-dependent) material properties with dynamic reconfigurability. We use dynamic covalent chemistry to create reversible gels of ITO nanocrystals under conditions guided by thermodynamic theory and rationalized with the help of simulations. The infrared optical response of the gels is broadened by coupling between the LSPR of the nanocrystals. Since assembly is reversible, the ITO nanocrystals gels are switchable infrared absorbers. Overall, plasmonic metal oxide nanocrystals offer compelling opportunities as building blocks for dynamic and tunable optical and electronic materials.
ABOUT THE SPEAKER
Delia J. Milliron is the T. Brockett Hudson Professor and Department Chair of Chemical Engineering at the University of Texas at Austin. Dr. Milliron received her PhD in Chemistry from the University of California, Berkeley, in 2004. From 2004 to 2008 she worked for IBM’s research division, initially as a postdoctoral researcher and then as a member of the research staff. In 2008, she joined the Molecular Foundry, Lawrence Berkeley National Lab, where she served as the Director of the Inorganic Nanostructures Facility and later as the Deputy Director. Dr. Milliron’s research involves nanocrystal-based materials in which abundant interfacial area and confined volume produce drastically different properties than those of homogeneous bulk materials. Such properties represent a growing opportunity to design materials to meet simultaneous, sometimes disparate performance requirements for applications including electronics and clean energy.