Presentation Title: Advanced Concepts for Ultra- Highly Efficient Conversion of Solar Photons into Photovoltaics and Solar Fuels Based on Nanostructures
Prof. Arthur Nozik presented this talk in the webinar on Nanomedicine, Nanomaterials and Nanotechnology organized by Vebleo
Affiliation:
1Department of Chemistry and Renewable & Sustainable Energy Institute (RASEI), University of Colorado, Boulder, CO 80309, USA
2National Renewable Energy Laboratory (NREL), Golden, CO 80401, USA
Biography
Dr. Arthur Nozik is a Senior Research Fellow Emeritus of NREL and Research Professor in the Department of Chemistry and Biochemistry at the University of Colorado, Boulder.
Dr. Arthur Nozik received his BChE from Cornell University in 1959 and his PhD in Physical Chemistry from Yale University in 1967. Before joining NREL in 1978, then known as the Solar Energy Research Institute (SERI), he conducted research at the Allied Chemical Corporation and American Cyanamid Corporation.
Dr. Nozik has established a leading position in the interdisciplinary fields of photoelectrochemistry, semiconductor-molecule interfaces, quantum size effects, electron relaxation dynamics in semiconductor quantum wells, quantum dots, quantum wires, and nanostructures, and applications of this science to improve solar photon conversion technologies.
He has published more than 270 peer-reviewed papers, proceedings, and book chapters in these fields and in the related fields of photocatalysis, heterogeneous catalysis, the optical, magnetic, and electrical properties of solids, and Mössbauer spectroscopy. He has been cited more than 38,000 times and presented more than 370 invited, plenary, and keynote talks.
Dr. Arthur Nozik has managed a large group of scientists engaged in basic and applied research on the direct photoconversion of light into solar fuels, chemicals, and electricity, and on the optical and electronic properties and applications of nanostructures. He has been awarded 11 U.S. patents and has received many national and international honors and awards.
Abstract
In order to utilize solar power for the production of solar electricity and solar fuels on a global scale, it will be necessary to develop solar photon conversion systems that have an appropriate combination of high efficiency (delivered watts/m2) and low capital cost ($/m2). One potential, long-term approach to attain high conversion efficiencies above the well-known Shockley-Queisser thermodynamic limit of 32% is to utilize the unique properties of quantum dot/rod (QD/QR) nanostructures to control the relaxation dynamics of photogenerated carriers to produce either enhanced photocurrent through efficient photogenerated electron-hole pair multiplication or enhanced photopotential through hot electron transport and transfer processes.
To achieve these desirable effects it is necessary to understand and control the dynamics of hot electron and hole relaxation, cooling, charge transport, and interfacial charge transfer of the photogenerated carriers. These fundamental dynamics in various bulk and nanoscale semiconductors have been studied for many years using transient absorption, photoluminescence, photocurrent, and THz spectroscopy with fs to ns time resolution The prediction that the generation of more than one electron-hole pair (which exist as excitons in size-quantized nanostructures) per absorbed photon would be an efficient process in QDs and QRs has been confirmed over the past years in different classes of materials and their architectures.
Very efficient and ultrafast multiple exciton generation (MEG), also called Carrier Multiplication (CM), from absorbed single high energy photons has been reported in many quantized semiconductors and associated solar photon conversion devices for solar electricity and solar fuels (e.g. H2) production.
Selected aspects of this work will be summarized and recent advances will be discussed, including the very remarkable and beneficial theoretical effects of combining MEG with solar concentration. Finally, the analogous MEG effect in molecules (called singlet fission) and its use in molecular-based solar cells will also be discussed.
This talk was delivered in the webinar organized by Vebleo