Prashant V. Kamat is a Rev. John A. Zahm, C.S.C., Professor of Science in the Department of Chemistry and Biochemistry and Radiation Laboratory at the University of Notre Dame. He is also a Concurrent Professor in the Department of Chemical and Biomolecular Engineering. He earned his doctoral degree (1979) in Physical Chemistry from the Bombay University, and postdoctoral research at Boston University (1979-1981) and University of Texas at Austin (1981-1983). He joined Notre Dame in 1983. Professor Kamat has for nearly four decades worked to build bridges between physical chemistry and material science to develop advanced nanomaterials that promise cleaner and more efficient light energy conversion.
He has directed DOE funded solar photochemistry research for the past 40 years. In addition to large multidisciplinary interdepartmental and research center programs, he has actively worked with industry-sponsored research. He has served on many national panels on nanotechnology and energy conversion processes. He has published more than 400 scientific papers that have been well recognized by the scientific community (80000+ citations, h-index 141 –Source Web of Science). Thomson-Reuters has featured him as one of the most cited researchers each year during 2014-2022. He is Fellow of AAAS, The Electrochemical Society, American Chemical Society and Materials Research Society. He is currently serving as an Editor-in-Chief of ACS Energy Letters.
Outstanding Junior Chemistry Award Winners will be acknowledged and the Gene Easter Award will be presented prior to Professor Kamat’s evening lecture.
Register for the evening program here.
Afternoon Lecture, 3PM The University of Akron, Mary Gladwin Hall Room 111
Light Energy Conversion with Halide Perovskite-Molecular Hybrids. Energy versus Electron Transfer
The flow of energy and electron transfer processes in semiconductor nanocrystal based light harvesting assemblies is dictated by the nature of the excited state interactions. Surface interaction of chromophore or redox active molecule which dictate the efficiency of energy/electron transfer, thus plays an important role in realizing photocatalytic and optoelectronic applications. Metal halide perovskite nanocrystals are interesting in the sense that they can either transfer energy or selectively transfer electrons or holes to the adsorbed molecules.
The presentation will focus on two specific scenarios of the flow of energy and electron processes in CsPbBr3 nanocrystal-molecular hybrids. The energy transfer is probed through three moleculr acceptors – rhodamine B (RhB), rhodamine isothiocyanate (RhB-NCS), and rose Bengal (RoseB), which contain an increasing degree of heavy atom pendant groups. When interacting with CsPbBr3 as an energy donor, photoluminescence excitation spectroscopy reveals that singlet energy transfer occurs with all three acceptors. However, the acceptor functionalization directly influences several key parameters that dictate the excited state interactions.
Electron and/or hole transfer from excited CsPbBr3 nanocrystals to a molecular relay present near the interface offers another avenue to directly convert light energy into chemical energy. Such interfacial electron transfer of semiconductor nanocrystals has been widely explored in photocatalytic processes. The relative energy level alignment of donors and acceptors to direct the flow of charge carriers becomes important in dictating electron transfer. By employing viologen as a probe, we have elucidated the factors controlling the interfacial electron transfer processes. A basic understanding of the fundamental differences between the two excited deactivation processes (energy and charge transfer) and ways to modulate them should enable design of more efficient light harvesting assemblies with semiconductor and molecular systems.
References:
- DuBose, J. T.; Kamat, P. V. Energy Versus Electron Transfer: Managing Excited-State Interactions in Perovskite Nanocrystal–Molecular Hybrids, Chemical Reviews 2022, 122, 12475–12494.
- DuBose, J. T.; Kamat, P. V. Efficacy of Perovskite Photocatalysis: Challenges to Overcome, ACS Energy Letters 2022, 7, 1994-2011.
- DuBose, J. T.; Kamat, P. V. Directing Energy Transfer in Halide Perovskite–Chromophore Hybrid Assemblies, Journal of the American Chemical Society 2021, 143, 19214–19223.
Evening Lecture, Kent State University, Integrated Science Building, Esplanade Commons
5:30 PM Networking
6:30 PM Dinner
7:00 PM Lecture
Dinner cost is $30 for professionals, $10 for students. The lecture is free and open to the public. Register here.
Reducing Carbon Footprint with Next Generation Photovoltaics
Silicon photovoltaics are regarded as part of green energy technology. However, they carry significantly longer (as high as 3 years) energy payback time. Semiconductor nanostructures are finding new ways to design light energy conversion devices (e.g., thin film solar cells and light emitting devices). The thin film design enabled through low temperature processing decreases the energy payback time. The decreased consumption of energy during the manufacture and the lessened use of semiconductor materials lowers the overall carbon footprint with energy payback time less than a year. The early studies focused on the synthesis of various semiconductor nanostructures and exploration of their size dependent optical and electronic properties. Careful engineering efforts in recent years have led to their integration in high efficiency thin film solar cells. Metal halide perovskite solar cells, in particular can now deliver efficiencies greater than 26%, thus matching the power conversion efficiency of silicon solar cells. Recent developments in utilizing semiconductor quantum dots for light energy conversion devices and how they can influence decreasing carbon footprint will be discussed. Efforts are needed to address the stability issues, to assess environmental impacts and to transform current practices of energy utilization.
Additional Readings
[1] Kamat, P. V. Quantum Dot Solar Cells. The Next Big Thing in Photovoltaics, J. Phys. Chem. Lett. 2013, 4, 908–918.
[2] DuBose, J. T.; Kamat, P. V., Efficacy of Perovskite Photocatalysis: Challenges to Overcome. ACS Energy Letters 2022, 7, 1994-2011
[3] DuBose, J. T.; Kamat, P. V., Hole Trapping in Halide Perovskites Induces Phase Segregation. Accounts of Materials Research 2022, 3, 761-771
[4] DuBose, J. T.; Kamat, P. V., Energy Versus Electron Transfer: Managing Excited-State Interactions in Perovskite Nanocrystal–Molecular Hybrids. Chemical Reviews 2022, 122, 15, 12475–12494
[5] Kamat, P. V.; Kuno, M., Halide Ion Migration in Perovskite Nanocrystals and Nanostructures. Accounts of Chemical Research 2021, 54 (3), 520-531.