Gary Wiederrecht, PhD

Argonne National Lab

 

Understanding ultrafast photoprocesses in nanostructures is important for realizing new opportunities related to technologies such as solar energy conversion and single photon emission for quantum optics applications. In this talk, I discuss our work in characterizing several ultrafast optical phenomena that are specifically enhanced in nanoscale structures. Examples include the ultrafast decay of plasmons into hot “nonthermal” plasmonic carriers and their potential importance to increasing efficiencies of photovoltaic and photocatalytic processes. We seek to spectroscopically characterize hot electrons on an ultrafast timescale, as well as to gain insight into design parameters for new nanostructures to create hot electrons in greater numbers. Physical insights into how to extract the hot carriers before loss of energy to thermalization is given. A second set of examples includes the design of excitonic nanostructures for light harvesting, which offer unique opportunities for tuning structure and the resultant energy transport properties. One class of materials described is metal-organic-frameworks (MOFs). Design parameters for increasing exciton transport through resonance energy transfer, and novel approaches to measuring the degree of exciton transport are described. Additional types of nanostructured systems and measurements with longer-range exciton transport are also described. Finally, an overview of the Center for Nanoscale Materials (CNM) user science program, which enables free access for work intended to be published to a wide variety of fabrication, synthesis, characterization, and theory capabilities, is provided. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE AC02-06CH11357.