TY - JOUR
T1 - Balancing Charge Transfer and Frenkel Exciton Coupling Leads to Excimer Formation in Molecular Dimers
T2 - Implications for Singlet Fission
AU - Bae, Youn Jue
AU - Shimizu, Daiki
AU - Schultz, Jonathan D.
AU - Kang, Gyeongwon
AU - Zhou, Jiawang
AU - Schatz, George C.
AU - Osuka, Atsuhiro
AU - Wasielewski, Michael R.
N1 - Funding Information:
This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award DE-FG02-99ER14999 (M.R.W.). G.K. and G.C.S. were supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award DE-SC000475. Y.B. gratefully acknowledges support from the Ryan Fellowship and the International Institute for Nanotechnology at Northwestern University. D.S. acknowledges a JSPS fellowship for young scientists and Grant-in-Aid for Scientific Research on Innovative Areas MEXT, “Science of Atomic Layers (SATL)”. J.D.S. acknowledges support from the National Science Foundation Graduate Research Fellowship Program under Grant DGE-1842165. This work made use of the IMSERC at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205), the State of Illinois, and the International Institute for Nanotechnology (IIN).
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/10/15
Y1 - 2020/10/15
N2 - Photoexcitation of molecular chromophore aggregates can form excimer states that play a significant role in photophysical processes such as charge and energy transfer as well as singlet fission. An excimer state is commonly defined as a superposition of Frenkel exciton and charge transfer states. In this work, we investigate the dynamics of excimer formation and decay in π-stacked 9,10-bis(phenylethynyl)anthracene (BPEA) covalent dimers appended to a xanthene spacer, where the electronic coupling between the two BPEA molecules is adjusted by changing their longitudinal molecular slip distances. Using exciton coupling calculations, we quantify the relative contributions of Frenkel excitons and charge transfer states and find that there is an upper and lower threshold of the charge transfer contribution for efficient excimer formation to occur. Knowing these thresholds can aid the design of molecular aggregates that optimize singlet fission.
AB - Photoexcitation of molecular chromophore aggregates can form excimer states that play a significant role in photophysical processes such as charge and energy transfer as well as singlet fission. An excimer state is commonly defined as a superposition of Frenkel exciton and charge transfer states. In this work, we investigate the dynamics of excimer formation and decay in π-stacked 9,10-bis(phenylethynyl)anthracene (BPEA) covalent dimers appended to a xanthene spacer, where the electronic coupling between the two BPEA molecules is adjusted by changing their longitudinal molecular slip distances. Using exciton coupling calculations, we quantify the relative contributions of Frenkel excitons and charge transfer states and find that there is an upper and lower threshold of the charge transfer contribution for efficient excimer formation to occur. Knowing these thresholds can aid the design of molecular aggregates that optimize singlet fission.
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U2 - 10.1021/acs.jpca.0c07646
DO - 10.1021/acs.jpca.0c07646
M3 - Article
C2 - 32975426
AN - SCOPUS:85093538871
SN - 1089-5639
VL - 124
SP - 8478
EP - 8487
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 41
ER -