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Physics Colloquium, Manipulating Exciton Dynamics for Energy Conversion Applications

Physics Colloquium, Matthew Sfeir, Manipulating Exciton Dynamics for Energy Conversion Applications
When Nov 28, 2018
from 04:00 PM to 05:00 PM
Where MR418N
Contact Name
Contact Phone 212-650-7443
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Physics Colloquium

Matthew Sfeir

Chemical physicist, Brookhaven National Laboratory's Center for Functional Nanomaterials, Upton, NY

Manipulating Exciton Dynamics for Energy Conversion Applications

Abstract: The promise of nanotechnology lies in the emergence of novel electronic and photonic phenomena with the potential for new device technologies. For example, optical transitions at the nanoscale frequently result from strongly absorbing excitons, whose electronic structure and dynamics are shape, size, and morphology dependent. However, since excitons are bound states, device concepts that exploit the unique photophysics of excitons, for example, organic photovoltaics or multiple exciton generation solar cells, depend critically on the ability to direct specific favorable conversion processes and suppress unfavorable ones. Here I will discuss how ultrafast optical spectroscopy is an important tool to understand the success (and failure) of nanoscale device concepts. I will demonstrate how the unique optical signature of excitons allow for dynamical tracking of energy conversion processes on ultrafast time scales. These optical signatures can be used to understand the harvesting of excitons in nanoscale lasers, photocatalytic water splitting devices, and photovoltaics. I will show how the first few picoseconds after light absorption are crucial to understanding the overall performance of a nanomaterial-based energy device.

Dr. Sfeir studies the unique optical processes of nanoscale materials and translates the resulting discoveries into technologies.  The Electronic Nanomaterials Group at the Center for Functional Nanomaterials (CFN) is a DOE Office of Science User Facility at Brookhaven and one of five DOE Nanoscale Science Research Centers. For the past decade at the CFN, Sfeir has been studying the most basic photophysical properties (those induced by light) of materials and translating the resulting discoveries into technologies. In particular, he has recently made significant advancements in two areas: thin-film optical devices and solar cell materials.