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Title: Quintet-triplet mixing determines the fate of the multiexciton state produced by singlet fission in a terrylenediimide dimer at room temperature

Abstract

Singlet fission (SF) is a photophysical process in which one of two adjacent organic molecules absorbs a single photon, resulting in rapid formation of a correlated triplet pair (T 1 T 1 ) state whose spin dynamics influence the successful generation of uncorrelated triplets (T 1 ). Femtosecond transient visible and near-infrared absorption spectroscopy of a linear terrylene-3,4:11,12-bis(dicarboximide) dimer (TDI 2 ), in which the two TDI molecules are directly linked at one of their imide positions, reveals ultrafast formation of the (T 1 T 1 ) state. The spin dynamics of the (T 1 T 1 ) state and the processes leading to uncoupled triplets (T 1 ) were studied at room temperature for TDI 2 aligned in 4-cyano-4′-pentylbiphenyl (5CB), a nematic liquid crystal. Time-resolved electron paramagnetic resonance spectroscopy shows that the (T 1 T 1 ) state has mixed 5 (T 1 T 1 ) and 3 (T 1 T 1 ) character at room temperature. This mixing is magnetic field dependent, resulting in a maximum triplet yield at ∼200 mT. The accessibility of the 3 (T 1 T 1 ) state opens a pathway for triplet–triplet annihilation that produces a single uncorrelated T 1 state. The presencemore » of the 5 (T 1 T 1 ) state at room temperature and its relationship with the 1 (T 1 T 1 ) and 3 (T 1 T 1 ) states emphasize that understanding the relationship among different (T 1 T 1 ) spin states is critical for ensuring high-yield T 1 formation from singlet fission.« less

Authors:
ORCiD logo; ORCiD logo; ; ; ; ; ORCiD logo; ORCiD logo
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1505237
Grant/Contract Number:  
FG02-99ER14999
Resource Type:
Journal Article: Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Volume: 116 Journal Issue: 17; Journal ID: ISSN 0027-8424
Publisher:
Proceedings of the National Academy of Sciences
Country of Publication:
United States
Language:
English

Citation Formats

Chen, Michelle, Krzyaniak, Matthew D., Nelson, Jordan N., Bae, Youn Jue, Harvey, Samantha M., Schaller, Richard D., Young, Ryan M., and Wasielewski, Michael R. Quintet-triplet mixing determines the fate of the multiexciton state produced by singlet fission in a terrylenediimide dimer at room temperature. United States: N. p., 2019. Web. doi:10.1073/pnas.1820932116.
Chen, Michelle, Krzyaniak, Matthew D., Nelson, Jordan N., Bae, Youn Jue, Harvey, Samantha M., Schaller, Richard D., Young, Ryan M., & Wasielewski, Michael R. Quintet-triplet mixing determines the fate of the multiexciton state produced by singlet fission in a terrylenediimide dimer at room temperature. United States. doi:10.1073/pnas.1820932116.
Chen, Michelle, Krzyaniak, Matthew D., Nelson, Jordan N., Bae, Youn Jue, Harvey, Samantha M., Schaller, Richard D., Young, Ryan M., and Wasielewski, Michael R. Thu . "Quintet-triplet mixing determines the fate of the multiexciton state produced by singlet fission in a terrylenediimide dimer at room temperature". United States. doi:10.1073/pnas.1820932116.
@article{osti_1505237,
title = {Quintet-triplet mixing determines the fate of the multiexciton state produced by singlet fission in a terrylenediimide dimer at room temperature},
author = {Chen, Michelle and Krzyaniak, Matthew D. and Nelson, Jordan N. and Bae, Youn Jue and Harvey, Samantha M. and Schaller, Richard D. and Young, Ryan M. and Wasielewski, Michael R.},
abstractNote = {Singlet fission (SF) is a photophysical process in which one of two adjacent organic molecules absorbs a single photon, resulting in rapid formation of a correlated triplet pair (T 1 T 1 ) state whose spin dynamics influence the successful generation of uncorrelated triplets (T 1 ). Femtosecond transient visible and near-infrared absorption spectroscopy of a linear terrylene-3,4:11,12-bis(dicarboximide) dimer (TDI 2 ), in which the two TDI molecules are directly linked at one of their imide positions, reveals ultrafast formation of the (T 1 T 1 ) state. The spin dynamics of the (T 1 T 1 ) state and the processes leading to uncoupled triplets (T 1 ) were studied at room temperature for TDI 2 aligned in 4-cyano-4′-pentylbiphenyl (5CB), a nematic liquid crystal. Time-resolved electron paramagnetic resonance spectroscopy shows that the (T 1 T 1 ) state has mixed 5 (T 1 T 1 ) and 3 (T 1 T 1 ) character at room temperature. This mixing is magnetic field dependent, resulting in a maximum triplet yield at ∼200 mT. The accessibility of the 3 (T 1 T 1 ) state opens a pathway for triplet–triplet annihilation that produces a single uncorrelated T 1 state. The presence of the 5 (T 1 T 1 ) state at room temperature and its relationship with the 1 (T 1 T 1 ) and 3 (T 1 T 1 ) states emphasize that understanding the relationship among different (T 1 T 1 ) spin states is critical for ensuring high-yield T 1 formation from singlet fission.},
doi = {10.1073/pnas.1820932116},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
issn = {0027-8424},
number = 17,
volume = 116,
place = {United States},
year = {2019},
month = {4}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1073/pnas.1820932116

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