FacebookTwitterYouTube RSS Feed

Excitons and plasmons in nanoscale systems:

Event Details

Event Dates: 

Thursday, October 25, 2012 - 6:00am

Speaker Name(s): 

Jao van de Lagemaat

Speaker Affiliation(s): 

NREL
Seminar Type/Subject

Event Details & Abstract: 

Because of the growing populace and standard of living, many terawatts of energy will be needed in the near future. The sun is the largest source of carbon-neutral and renewable energy that we have available and it is the only source that can provide terawatts of energy without depleting rapidly or causing major environmental and climate concerns. To fulfill this role, revolutionary approaches to solar energy conversion are needed that provide energy at very high efficiency at very low prices. The unique properties of self-organic and nanoscale systems possibly enable such a future by combining ease of processing and low cost with third-generation photoconversion processes that enable high efficiency.Examples of third generation photoconversion involve semiconductor quantum dots, carbon nanostructures and organic semiconductors.  The presence of excitonic states in these systems at room temperature allows for processes such as multiple exciton generation, singlet fission and long-range energy transfer that are currently being researched for applications in the next generation of high efficiency solar energy conversion. These processes have been theorized to allow for the breaking of traditional limits to solar cell efficiency. However, much remains unknown about how to control these processes. A new approachto this control, which will be discussed in this talk, involves the coupling between excitons and surface plasmons in nanoscale systems and allows for the outcome of photoexcitation to be directed to a desired final state that most optimally converts sunlight into electrical energy or fuels. Approaches such as this can possibly drive future solar cell efficiencies above traditional barriers and provide one avenue to solving the energy problem.