@article{cd37ac0e2c2c4193ad602142aa15b2cf,
title = "Spectrally Resolved Ultrafast Exciton Transfer in Mixed Perovskite Quantum Wells",
abstract = "Solution-processed perovskite quantum wells have been used to fabricate increasingly efficient and stable optoelectronic devices. Little is known about the dynamics of photogenerated excitons in perovskite quantum wells within the first few hundred femtoseconds-a crucial time scale on which energy and charge transfer processes may compete. Here we use ultrafast transient absorption and two-dimensional electronic spectroscopy to clarify the movement of excitons and charges in reduced-dimensional perovskite solids. We report excitonic funneling from strongly to weakly confined perovskite quantum wells within 150 fs, facilitated by strong spectral overlap and orientational alignment among neighboring wells. This energy transfer happens on time scales orders of magnitude faster than charge transfer, which we find to occur instead over 10s to 100s of picoseconds. Simulations of both F{\"o}rster-type interwell exciton transfer and free carrier charge transfer are in agreement with these experimental findings, with theoretical exciton transfer calculated to occur in 100s of femtoseconds. {\textcopyright}",
author = "Proppe, {Andrew H.} and Elkins, {Madeline H.} and Oleksandr Voznyy and Pensack, {Ryan D.} and Felipe Zapata and Besteiro, {Lucas V.} and Quan, {Li Na} and Rafael Quintero-Bermudez and Petar Todorovic and Kelley, {Shana O.} and Govorov, {Alexander O.} and Gray, {Stephen K.} and Ivan Infante and Sargent, {Edward H.} and Scholes, {Gregory D.}",
note = "Funding Information: M.H.E., E.H.S., and G.D.S. gratefully acknowledge the support of the Canadian Institute for Advanced Research through its Bioinspired Solar Energy program. Additionally, E.H.S. acknowledges the Ontario Fund: Research Excellence Program, the Natural Sciences and Engineering Research Council of Canada, and a University of Toronto Connaught grant. G.D.S. thanks Princeton University through the Innovation Fund for New Ideas in the Natural Sciences. I.I. acknowledges The Netherlands Organization of Scientific Research (NWO) for financial support through the Innovational Research Incentive (Vidi) Scheme (Grant No. 723.013.002). The AIMS simulations were carried out on the Dutch national e-infrastructure with the support of the SURF Cooperative. This work was performed, in part, at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility, and supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. A.H.P. is supported by the Fonds de Recherche du Que{\'b} ec-Nature et Technologies and the Ontario Graduate Scholarship program. We thank A. Jain, M. Korkusinsk,I and A. Aspuru-Guzik for fruitful discussions. Publisher Copyright: Copyright {\textcopyright} 2019 American Chemical Society.",
year = "2019",
month = feb,
day = "7",
doi = "10.1021/acs.jpclett.9b00018",
language = "English (US)",
volume = "10",
pages = "419--426",
journal = "Journal of Physical Chemistry Letters",
issn = "1948-7185",
publisher = "American Chemical Society",
number = "3",
}