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The Link Lab

Group Photo February 2017

The overall goal of research in the Link Lab is to understand the physical principles that govern the interactions of plasmonic nanoparticles with each other and their molecular environment and to determine the emerging collective optical properties that arise from novel composite nanomaterials.
Building new photonic materials and devices from the bottom up is a central goal in nanoscience. Using plasmonic nanoparticles as building blocks requires a detailed understanding of how the optical properties of the individual nanoparticles change as they are assembled into complex, higher order structures. These changes occur because interactions between plasmonic nanoparticles lead to new phenomena that depend not only on the dimensions and shapes of the individual nanoparticles but also their relative distances and orientations. An additional level of complexity exists when nanoparticles are prepared and assembled by chemical synthesis and soft lithography methods because irregularities or ‘defects’ in particle size, shape, and ordering are inherently present in those systems. Despite these challenges, the advantages of chemically prepared nanoparticles include highly crystalline structures and small interparticle distances, allowing for the strongest plasmon response. Therefore, the advantageous properties of chemically prepared nanoparticles make it worthwhile to understand and control the challenges introduced by polydispersity, especially given the many assembly strategies already developed so far. To fully exploit these nanoparticle assemblies and to advance the field, it is first necessary to determine the effect of imperfections on the functional properties of nanomaterials consisting of many interacting plasmonic nanoparticles. In addition to plasmon coupling between nanoparticles, their interaction with the environment is also a key factor for many applications of plasmonic nanoparticles ranging from catalytic substrates to drug delivery agents. To address these complex issues on a microscopic scale, the Link lab is applying and developing single molecule and particle spectroscopy techniques, which, when correlated with structural characterization of the same nanostructure using electron microscopes and detailed electromagnetic modeling, allow us to address the following important thematic questions:
1) How do the optical properties of nanoparticle assemblies depend on the morphology of the overall structure and what is the role of disorder with respect to nanoparticle size, shape, and positioning?
2) How is the initial plasmon energy dissipated in plasmonic nanostructures and can it initiate chemistry?
3) How do nanoparticles interact with proteins and what is the role of the protein corona on their biological fate?
While these questions address mainly fundamental issues, the long-term research is strongly guided by possible applications of assembled nanomaterials as plasmonic waveguides and antennas, active plasmonic displays, plasmonic photo-catalysts, and drug delivery agents based on the principles learned from understanding coupling between plasmonic nanoparticles and their interactions with the surrounding molecular environment.
We invite you to take a closer look at our current research projects. Please feel free to contact us if you would like to learn more.