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Title: Exciton Correlations in Intramolecular Singlet Fission

Abstract

We have synthesized a series of asymmetric pentacene-tetracene heterodimers with a variable-length conjugated bridge that undergo fast and efficient intramolecular singlet fission (iSF). These compounds have distinct singlet and triplet energies, which allow us to study the spatial dynamics of excitons during the iSF process, including the significant role of exciton correlations in promoting triplet pair generation and recombination. We demonstrate that the primary photoexcitations in conjugated dimers are delocalized singlets that enable fast and efficient iSF. However, in these asymmetric dimers, the singlet becomes more localized on the lower energy unit as the length of the bridge is increased, slowing down iSF relative to analogous symmetric dimers. We resolve the recombination kinetics of the inequivalent triplets produced via iSF, and find that they primarily decay via concerted processes. By identifying different decay channels, including delayed fluorescence via triplet-triplet annihilation, we can separate transient species corresponding to both correlated triplet pairs and uncorrelated triplets. Recombination of the triplet pair proceeds rapidly despite our experimental and theoretical demonstration that individual triplets are highly localized and unable to be transported across the conjugated linker. In this class of compounds, the rate of formation and yield of uncorrelated triplets increases with bridge length.more » Overall, these constrained, asymmetric systems provide a unique platform to isolate and study transient species essential for singlet fission, which are otherwise difficult to observe in symmetric dimers or condensed phases.« less

Authors:
 [1];  [1];  [1];  [2];  [1];  [1];  [2]
  1. Columbia Univ., New York, NY (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1329780
Report Number(s):
BNL-112603-2016-JA
Journal ID: ISSN 0002-7863; R&D Project: 16063; 16058; KC0403020
Grant/Contract Number:  
SC00112704
Resource Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 138; Journal Issue: 23; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Center for Functional Nanomaterials

Citation Formats

Sanders, Samuel N., Kumarasamy, Elango, Pun, Andrew B., Appavoo, Kannatassen, Steigerwald, Michael L., Campos, Luis M., and Sfeir, Matthew Y. Exciton Correlations in Intramolecular Singlet Fission. United States: N. p., 2016. Web. doi:10.1021/jacs.6b00657.
Sanders, Samuel N., Kumarasamy, Elango, Pun, Andrew B., Appavoo, Kannatassen, Steigerwald, Michael L., Campos, Luis M., & Sfeir, Matthew Y. Exciton Correlations in Intramolecular Singlet Fission. United States. doi:10.1021/jacs.6b00657.
Sanders, Samuel N., Kumarasamy, Elango, Pun, Andrew B., Appavoo, Kannatassen, Steigerwald, Michael L., Campos, Luis M., and Sfeir, Matthew Y. Mon . "Exciton Correlations in Intramolecular Singlet Fission". United States. doi:10.1021/jacs.6b00657. https://www.osti.gov/servlets/purl/1329780.
@article{osti_1329780,
title = {Exciton Correlations in Intramolecular Singlet Fission},
author = {Sanders, Samuel N. and Kumarasamy, Elango and Pun, Andrew B. and Appavoo, Kannatassen and Steigerwald, Michael L. and Campos, Luis M. and Sfeir, Matthew Y.},
abstractNote = {We have synthesized a series of asymmetric pentacene-tetracene heterodimers with a variable-length conjugated bridge that undergo fast and efficient intramolecular singlet fission (iSF). These compounds have distinct singlet and triplet energies, which allow us to study the spatial dynamics of excitons during the iSF process, including the significant role of exciton correlations in promoting triplet pair generation and recombination. We demonstrate that the primary photoexcitations in conjugated dimers are delocalized singlets that enable fast and efficient iSF. However, in these asymmetric dimers, the singlet becomes more localized on the lower energy unit as the length of the bridge is increased, slowing down iSF relative to analogous symmetric dimers. We resolve the recombination kinetics of the inequivalent triplets produced via iSF, and find that they primarily decay via concerted processes. By identifying different decay channels, including delayed fluorescence via triplet-triplet annihilation, we can separate transient species corresponding to both correlated triplet pairs and uncorrelated triplets. Recombination of the triplet pair proceeds rapidly despite our experimental and theoretical demonstration that individual triplets are highly localized and unable to be transported across the conjugated linker. In this class of compounds, the rate of formation and yield of uncorrelated triplets increases with bridge length. Overall, these constrained, asymmetric systems provide a unique platform to isolate and study transient species essential for singlet fission, which are otherwise difficult to observe in symmetric dimers or condensed phases.},
doi = {10.1021/jacs.6b00657},
journal = {Journal of the American Chemical Society},
number = 23,
volume = 138,
place = {United States},
year = {2016},
month = {5}
}

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Works referencing / citing this record:

Triplet Transfer Mediates Triplet Pair Separation during Singlet Fission in 6,13-Bis(triisopropylsilylethynyl)-Pentacene
journal, October 2017

  • Grieco, Christopher; Doucette, Grayson S.; Munro, Jason M.
  • Advanced Functional Materials, Vol. 27, Issue 46
  • DOI: 10.1002/adfm.201703929

Intramolecular Singlet Fission in an Antiaromatic Polycyclic Hydrocarbon
journal, July 2017

  • Wu, Yishi; Wang, Yuancheng; Chen, Jianwei
  • Angewandte Chemie International Edition, Vol. 56, Issue 32
  • DOI: 10.1002/anie.201704668

Charge-Transfer Character in a Covalent Diketopyrrolopyrrole Dimer: Implications for Singlet Fission
journal, October 2017

  • Mauck, Catherine M.; Bae, Youn Jue; Chen, Michelle
  • ChemPhotoChem, Vol. 2, Issue 3
  • DOI: 10.1002/cptc.201700135

Efficient triplet pair separation from intramolecular singlet fission in dibenzopentalene derivatives
journal, May 2019


The entangled triplet pair state in acene and heteroacene materials
journal, July 2017

  • Yong, Chaw Keong; Musser, Andrew J.; Bayliss, Sam L.
  • Nature Communications, Vol. 8, Issue 1
  • DOI: 10.1038/ncomms15953

Elaborately Tuning Intramolecular Electron Transfer Through Varying Oligoacene Linkers in the Bis(diarylamino) Systems
journal, November 2016

  • Zhang, Jing; Chen, Zhao; Yang, Lan
  • Scientific Reports, Vol. 6, Issue 1
  • DOI: 10.1038/srep36310

The butterfly effect in bisfluorenylidene-based dihydroacenes: aggregation induced emission and spin switching
journal, January 2019

  • Yin, Xiaodong; Low, Jonathan Z.; Fallon, Kealan J.
  • Chemical Science, Vol. 10, Issue 46
  • DOI: 10.1039/c9sc04096j

Triplet Transfer Mediates Triplet Pair Separation during Singlet Fission in 6,13-Bis(triisopropylsilylethynyl)-Pentacene
journal, October 2017

  • Grieco, Christopher; Doucette, Grayson S.; Munro, Jason M.
  • Advanced Functional Materials, Vol. 27, Issue 46
  • DOI: 10.1002/adfm.201703929

Intramolecular Singlet Fission in an Antiaromatic Polycyclic Hydrocarbon
journal, July 2017

  • Wu, Yishi; Wang, Yuancheng; Chen, Jianwei
  • Angewandte Chemie International Edition, Vol. 56, Issue 32
  • DOI: 10.1002/anie.201704668

Charge-Transfer Character in a Covalent Diketopyrrolopyrrole Dimer: Implications for Singlet Fission
journal, October 2017

  • Mauck, Catherine M.; Bae, Youn Jue; Chen, Michelle
  • ChemPhotoChem, Vol. 2, Issue 3
  • DOI: 10.1002/cptc.201700135

Efficient triplet pair separation from intramolecular singlet fission in dibenzopentalene derivatives
journal, May 2019


The entangled triplet pair state in acene and heteroacene materials
journal, July 2017

  • Yong, Chaw Keong; Musser, Andrew J.; Bayliss, Sam L.
  • Nature Communications, Vol. 8, Issue 1
  • DOI: 10.1038/ncomms15953

Elaborately Tuning Intramolecular Electron Transfer Through Varying Oligoacene Linkers in the Bis(diarylamino) Systems
journal, November 2016

  • Zhang, Jing; Chen, Zhao; Yang, Lan
  • Scientific Reports, Vol. 6, Issue 1
  • DOI: 10.1038/srep36310

The butterfly effect in bisfluorenylidene-based dihydroacenes: aggregation induced emission and spin switching
journal, January 2019

  • Yin, Xiaodong; Low, Jonathan Z.; Fallon, Kealan J.
  • Chemical Science, Vol. 10, Issue 46
  • DOI: 10.1039/c9sc04096j