Plasmonics and Nanophotonic Materials

Vials of intensely colored silver nanoparticles
Colloidal silver solutions of different sizes and shapes of silver nanospheres and triangular silver nanoprisms show the dramatic optical properties of plasmonic nanoparticles.

 

Plasmonic nanomaterials, such as gold and silver nanoparticles exhibit distinct localized surface plasmon resonances (LSPR) upon excitation with light.  These plasmon resonances are responsible for the intense colors of metallic nanoparticles, and open the door for new optical functionality arising from collective electromagnetic coupling effects and the concentration of incident light into electromagnetic hot spots.

 

We use both experimental and theoretical tools to gain fundamental understanding of the optical and electronic properties of plasmonic metallic nanoparticles for use in applications from sensing to solar energy harvesting.

 

Specifically, we are interested in:

 

  1. Combining optically-active plasmonic nanoparticles and stimuli-responsive media to design responsive plasmonic nanomaterials. These materials offer great promise for designing next-generation sensors, actuators, and reconfigurable materials, for instance, by designing responses that differentiate specific from non-specific binding, or receptors that can alter their binding affinity to adapt their dynamic range to the analytical conditions at hand.To date, our group has been particularly focused on integrating plasmonic nanoparticles with responsive media such as DNA, hydrogels and azobenzene which can respond to salt, temperature and light, and providing guidelines for improving their performance.
    2. Photograph of photoresponsive DNA-linked nanoparticle solutions
    Color-changing solutions turn from clear to intensely colored upon exposure to different wavelengths of light. This result was achieved using photoswitchable DNA-linked gold nanoparticles. Nano Letters, 12 (2), pp 893-898 (2012)
  2. Understanding and designing effective pathways to use plasmonic nanoparticles for solar energy harvesting. Due to their enhanced far-field scattering and near-field optical intensity, plasmonic nanoparticles are expected to improve light harvesting in organic photovoltaics, water splitting and photocatalysis, among other applications.Combining our experimental expertise in spectroscopy and theoretical expertise in finite-difference time-domain (FDTD) simulation, we desire to gain a mechanistic understanding of these plasmon-enhanced processes and provide instructive insight into new pathways to harvest solar energy using plasmonic nanoparticles.