OSE Seminars
Plasmonic Nanomaterials for Optical-to-Electrical Energy Conversion
Presented by Professor Matthew Sheldon, Departments of Chemistry and Materials Science & Engineering at Texas A&M University
Recent advances in subwavelength metal optics, e.g. nanophotonics, metamaterials, and plasmonics, provide several new examples where nanostructured metals perform the separate tasks of absorption and charge separation necessary for photovoltaic power conversion. Nanostructured metals are extremely efficient broadband absorbers of radiation, with tailorable optical properties throughout the visible and infrared spectrum. It is traditionally assumed that the lack of a band gap and consequent fast electronic relaxation (~fs) and short mean free path (~ 100 nm) hinders efficient carrier collection. However, new phenomena have been observed resulting from the remarkable energy concentration and nanoscale collection geometry afforded by plasmonic systems. In this talk, I will describe two ongoing studies in our laboratory that exemplify opportunities for metal-based optical energy conversion: (1) Excitation with circularly polarized illumination can induce strong, persistent electrical drift currents in resonant metal nanostructures via the inverse faraday effect. (2) The remarkable thermal and optical energy concentration provided by plasmonic resonances can enable a new thermodynamic power cycle whereby photo-excited 'hot' electrons and resonant photothermal heating provides a dual excitation mechanism for electron emission. Because this process is closely related to purely thermionic emission, we label an optical power-converting device based on this mechanism a Hot Electron Enhanced Thermionic Emission (HEETE) converter.
11:00 am, Thursday, October 6, 2016
Room 103, Center for High Tech Materials
Science and Technology Park - South Campus
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