Cascade Electron Transfer Induces Slow Hot Carrier Relaxation in CsPbBr3 Asymmetric Quantum Wells
Merdad, Noor A.
Mohammed, Omar F.
KAUST DepartmentKAUST Solar Center (KSC)
KAUST Catalysis Center (KCC)
Physical Science and Engineering (PSE) Division
KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
Material Science and Engineering Program
Chemical Science Program
Embargo End Date2022-06-28
Permanent link to this recordhttp://hdl.handle.net/10754/669814
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AbstractWe report an engineering approach not only to delay hot carrier equilibrium but also to slow the cooling rate of CsPbBr3-based multiple quantum wells (MQWs), as evident from femtosecond transient absorption measurements and density functional theory calculations. Three energetically cascaded CsPbBr3 perovskite layers (stacked with thicknesses of 3, 7, and 20 nm for asymmetric MQWs and 20, 20, and 20 nm for symmetric MQWs) are separated by a 5 nm organic barrier of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline. Time-resolved data demonstrate that the sequential hot-electron transfer between CsPbBr3 layers mediates the delayed hot carrier equilibrium in the asymmetric MQWs. Interestingly, the delayed hot carrier equilibrium is followed by a much slower relaxation in asymmetric MQWs (40 ps) than symmetric ones (3.2 ps), which could be attributed to the decoupling of a hot electron–hole originating from hot electron transfer. Our findings provide a promising approach for efficient hot carrier extraction in solar cells that exceed the Shockley–Queisser limit.
CitationMaity, P., Merdad, N. A., Yin, J., Lee, K. J., Sinatra, L., Bakr, O. M., & Mohammed, O. F. (2021). Cascade Electron Transfer Induces Slow Hot Carrier Relaxation in CsPbBr3 Asymmetric Quantum Wells. ACS Energy Letters, 2602–2609. doi:10.1021/acsenergylett.1c01142
SponsorsThis work was supported by the King Abdullah University of Science and Technology (KAUST).
PublisherAmerican Chemical Society (ACS)
JournalACS Energy Letters
Except where otherwise noted, this item's license is described as This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Energy Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acsenergylett.1c01142.