06 Mar, 2019 (Wed)Time:
SpeakerProf. Yanfa Yan
Ohio Research Scholar Endowed Chair
Photovoltaics Innovation and Commercialization
Department of Physics and Astronomy
University of Toledo (UT)
The low-temperature solution processability and bandgap tunability make the metal halide perovskites an ideal candidate for fabricating all-perovskite tandem solar cells, which can overcome the Shockley-Queisser (SQ) radiative efficiency limits for single-junction cells. However, the lack of high-quality low-bandgap perovskite absorber layers seriously hampers the development of efficient and stable two-terminal monolithic all-perovskite tandem solar cells. In this talk, we report our strategies for producing high quality mixed tin-lead low-bandgap (~1.25 eV) perovskite absorber layers. The improved electronic properties enabled us to fabricate efficient low-bandgap perovskite solar cells using thick absorber layers, which is a requisite for efficient tandem solar cells. With such improvement, we were able to fabricate efficient two-terminal and four-terminal all-perovskite tandem solar cells with a champion power conversion efficiency of exceeding 21% and 23%, respectively. The efficiencies were retained to 85% of their initial performance after 80 hours of operation under continuous illumination.
Biography of the speaker:
Yanfa Yan is a Professor and an Ohio Research Scholar Endowed Chair for Photovoltaics Innovation and Commercialization in the Department of Physics and Astronomy at the University of Toledo (UT). He earned MS and Ph D in Physics from Wuhan University. Previously, he was a Principal Scientist at the National Renewable Energy Laboratory (NREL), USA. His research interest includes (1) Theory of defect physics and electronic properties in semiconductors; (2) Materials synthesis and thin film solar cell fabrication; and Nanoscale characterization of thin film solar cell materials. His current research efforts include developing processes to fabricate high efficiency thin-film solar cells (CdTe and perovskite). He has received DOE/EERE Young Investigator and R&D 100 awards. He is a Fellow of the American Physical Society.
OrganizerProf. W.C.H. Choy
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