Ming L. Tang of the University of California Riverside is supported by the Macromolecular, Supramolecular and Nanochemistry program in a CAREER award to link nanoparticles together in uniquely well-defined ways. Nanoparticles made of gold and other noble metals can exhibit surface plasmon modes that are particularly effective at absorbing or scattering light in specific regions of the visible spectrum. This research is to hook them together in selective ways, the goal being to expand our ability to control interactions of light with matter at the nanoscale level. The approach is by chemical means, so that one can readily scale up the synthesis of these assemblies. The education component of this CAREER project is to deliver to the greater public the excitement of the fascinating properties of plasmonic nanoparticles. It includes the creation of a nanomaterials-focused, discovery-based laboratory course, "Painting with Plasmons and Polymers," for first year undergraduate students. This represents a new addition to the University of California Riverside's (UCR's) Learning Community program, which has been shown to increase retention rates of STEM majors and push 4-year graduation rates from 24% to 40%. First year student leaders from this class are expected to engage local middle and high school students with scientific demonstrations and to inspire them with stories about their personal path towards a STEM degree. The PI mentors students and teachers from these schools by providing them an opportunity to work in her research laboratory along with graduate students and undergraduates.

The goal of controlling nanoscale light-matter interactions in nanoparticle assemblies is achieved by inducing strong electric and magnetic transitions, particularly the latter, which are especially weak in the visible frequencies. Supra-molecular chemistry and solid phase synthesis is being used to create "monovalent gold" building blocks, i.e., gold nanoparticles each with a single binding site, as a powerful alternative to the current state of the art DNA-based self-assembly. The self-assembly method aims to control particles from 5-100 nm in size and to engineer inter-particle distances on the order of 1-20 nm. First, precise control over the distance between two nanoparticles of different composition creates heterodimers employed to identify modes disallowed by symmetry arguments. Second, by virtue of an inter-particle geometry dictated by a molecular scaffold, both electric and magnetic dipoles are induced in the circulating currents within the artificial molecule. Strong, tunable magnetic dipoles allow introduction of Fano resonances with high quality factors that are useful for sensing. And third, 3-D tetrahedral constructs with core-shell nanoparticles predicted to have overlapping electric and magnetic dipoles are being investigated.

Agency
National Science Foundation (NSF)
Institute
Division of Chemistry (CHE)
Application #
1351663
Program Officer
Suk-Wah Tam-Chang
Project Start
Project End
Budget Start
2014-05-01
Budget End
2019-04-30
Support Year
Fiscal Year
2013
Total Cost
$671,683
Indirect Cost
Name
University of California Riverside
Department
Type
DUNS #
City
Riverside
State
CA
Country
United States
Zip Code
92521