Competition between singlet fission and charge separation in solution-processed blend films of 6,13-bis(triisopropylsilylethynyl)pentacene with sterically-encumbered perylene-3,4

9,10-bis(dicarboximide)s

Charusheela Ramanan, Amanda L. Smeigh, John E. Anthony, Tobin J Marks, Michael R Wasielewski

Research output: Contribution to journalArticle

155 Citations (Scopus)

Abstract

The photophysics and morphology of thin films of N,N-bis(2,6- diisopropylphenyl)perylene-3,4:9,10-bis(dicarboximide) (1) and the 1,7-diphenyl (2) and 1,7-bis(3,5-di-tert-butylphenyl) (3) derivatives blended with 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pn) were studied for their potential use as photoactive layers in organic photovoltaic (OPV) devices. Increasing the steric bulk of the 1,7-substituents of the perylene-3,4:9,10- bis(dicarboximide) (PDI) impedes aggregation in the solid state. Film characterization data using both atomic force microscopy and X-ray diffraction showed that decreasing the PDI aggregation by increasing the steric bulk in the order 1 <2 <3 correlates with a decrease in the density/size of crystalline TIPS-Pn domains. Transient absorption spectroscopy was performed on ∼100 nm solution-processed TIPS-Pn:PDI blend films to characterize the charge separation dynamics. These results showed that selective excitation of the TIPS-Pn results in competition between ultrafast singlet fission ( 1*TIPS-Pn + TIPS-Pn → 2 3*TIPS-Pn) and charge transfer from 1*TIPS-Pn to PDIs 1-3. As the blend films become more homogeneous across the series TIPS-Pn:PDI 1 → 2 → 3, charge separation becomes competitive with singlet fission. Ultrafast charge separation forms the geminate radical ion pair state 1(TIPS-Pn +•-PDI -•) that undergoes radical pair intersystem crossing to form 3(TIPS-Pn +•-PDI -•), which then undergoes charge recombination to yield either 3*PDI or 3*TIPS-Pn. Energy transfer from 3*PDI to TIPS-Pn also yields 3*TIPS-Pn. These results show that multiple pathways produce the 3*TIPS-Pn state, so that OPV design strategies based on this system must utilize this triplet state for charge separation.

Original languageEnglish
Pages (from-to)386-397
Number of pages12
JournalJournal of the American Chemical Society
Volume134
Issue number1
DOIs
Publication statusPublished - Jan 11 2012

Fingerprint

Perylene
Agglomeration
Absorption spectroscopy
Energy transfer
Charge transfer
Atomic force microscopy
Crystalline materials
Derivatives
X ray diffraction
Thin films
bis(triisopropylsilylethynyl)pentacene
pentacene
Ions
Atomic Force Microscopy
Energy Transfer
X-Ray Diffraction
Genetic Recombination

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

@article{f9d64041a86747c59a145edef4288c0d,
title = "Competition between singlet fission and charge separation in solution-processed blend films of 6,13-bis(triisopropylsilylethynyl)pentacene with sterically-encumbered perylene-3,4: 9,10-bis(dicarboximide)s",
abstract = "The photophysics and morphology of thin films of N,N-bis(2,6- diisopropylphenyl)perylene-3,4:9,10-bis(dicarboximide) (1) and the 1,7-diphenyl (2) and 1,7-bis(3,5-di-tert-butylphenyl) (3) derivatives blended with 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pn) were studied for their potential use as photoactive layers in organic photovoltaic (OPV) devices. Increasing the steric bulk of the 1,7-substituents of the perylene-3,4:9,10- bis(dicarboximide) (PDI) impedes aggregation in the solid state. Film characterization data using both atomic force microscopy and X-ray diffraction showed that decreasing the PDI aggregation by increasing the steric bulk in the order 1 <2 <3 correlates with a decrease in the density/size of crystalline TIPS-Pn domains. Transient absorption spectroscopy was performed on ∼100 nm solution-processed TIPS-Pn:PDI blend films to characterize the charge separation dynamics. These results showed that selective excitation of the TIPS-Pn results in competition between ultrafast singlet fission ( 1*TIPS-Pn + TIPS-Pn → 2 3*TIPS-Pn) and charge transfer from 1*TIPS-Pn to PDIs 1-3. As the blend films become more homogeneous across the series TIPS-Pn:PDI 1 → 2 → 3, charge separation becomes competitive with singlet fission. Ultrafast charge separation forms the geminate radical ion pair state 1(TIPS-Pn +•-PDI -•) that undergoes radical pair intersystem crossing to form 3(TIPS-Pn +•-PDI -•), which then undergoes charge recombination to yield either 3*PDI or 3*TIPS-Pn. Energy transfer from 3*PDI to TIPS-Pn also yields 3*TIPS-Pn. These results show that multiple pathways produce the 3*TIPS-Pn state, so that OPV design strategies based on this system must utilize this triplet state for charge separation.",
author = "Charusheela Ramanan and Smeigh, {Amanda L.} and Anthony, {John E.} and Marks, {Tobin J} and Wasielewski, {Michael R}",
year = "2012",
month = "1",
day = "11",
doi = "10.1021/ja2080482",
language = "English",
volume = "134",
pages = "386--397",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
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TY - JOUR

T1 - Competition between singlet fission and charge separation in solution-processed blend films of 6,13-bis(triisopropylsilylethynyl)pentacene with sterically-encumbered perylene-3,4

T2 - 9,10-bis(dicarboximide)s

AU - Ramanan, Charusheela

AU - Smeigh, Amanda L.

AU - Anthony, John E.

AU - Marks, Tobin J

AU - Wasielewski, Michael R

PY - 2012/1/11

Y1 - 2012/1/11

N2 - The photophysics and morphology of thin films of N,N-bis(2,6- diisopropylphenyl)perylene-3,4:9,10-bis(dicarboximide) (1) and the 1,7-diphenyl (2) and 1,7-bis(3,5-di-tert-butylphenyl) (3) derivatives blended with 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pn) were studied for their potential use as photoactive layers in organic photovoltaic (OPV) devices. Increasing the steric bulk of the 1,7-substituents of the perylene-3,4:9,10- bis(dicarboximide) (PDI) impedes aggregation in the solid state. Film characterization data using both atomic force microscopy and X-ray diffraction showed that decreasing the PDI aggregation by increasing the steric bulk in the order 1 <2 <3 correlates with a decrease in the density/size of crystalline TIPS-Pn domains. Transient absorption spectroscopy was performed on ∼100 nm solution-processed TIPS-Pn:PDI blend films to characterize the charge separation dynamics. These results showed that selective excitation of the TIPS-Pn results in competition between ultrafast singlet fission ( 1*TIPS-Pn + TIPS-Pn → 2 3*TIPS-Pn) and charge transfer from 1*TIPS-Pn to PDIs 1-3. As the blend films become more homogeneous across the series TIPS-Pn:PDI 1 → 2 → 3, charge separation becomes competitive with singlet fission. Ultrafast charge separation forms the geminate radical ion pair state 1(TIPS-Pn +•-PDI -•) that undergoes radical pair intersystem crossing to form 3(TIPS-Pn +•-PDI -•), which then undergoes charge recombination to yield either 3*PDI or 3*TIPS-Pn. Energy transfer from 3*PDI to TIPS-Pn also yields 3*TIPS-Pn. These results show that multiple pathways produce the 3*TIPS-Pn state, so that OPV design strategies based on this system must utilize this triplet state for charge separation.

AB - The photophysics and morphology of thin films of N,N-bis(2,6- diisopropylphenyl)perylene-3,4:9,10-bis(dicarboximide) (1) and the 1,7-diphenyl (2) and 1,7-bis(3,5-di-tert-butylphenyl) (3) derivatives blended with 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pn) were studied for their potential use as photoactive layers in organic photovoltaic (OPV) devices. Increasing the steric bulk of the 1,7-substituents of the perylene-3,4:9,10- bis(dicarboximide) (PDI) impedes aggregation in the solid state. Film characterization data using both atomic force microscopy and X-ray diffraction showed that decreasing the PDI aggregation by increasing the steric bulk in the order 1 <2 <3 correlates with a decrease in the density/size of crystalline TIPS-Pn domains. Transient absorption spectroscopy was performed on ∼100 nm solution-processed TIPS-Pn:PDI blend films to characterize the charge separation dynamics. These results showed that selective excitation of the TIPS-Pn results in competition between ultrafast singlet fission ( 1*TIPS-Pn + TIPS-Pn → 2 3*TIPS-Pn) and charge transfer from 1*TIPS-Pn to PDIs 1-3. As the blend films become more homogeneous across the series TIPS-Pn:PDI 1 → 2 → 3, charge separation becomes competitive with singlet fission. Ultrafast charge separation forms the geminate radical ion pair state 1(TIPS-Pn +•-PDI -•) that undergoes radical pair intersystem crossing to form 3(TIPS-Pn +•-PDI -•), which then undergoes charge recombination to yield either 3*PDI or 3*TIPS-Pn. Energy transfer from 3*PDI to TIPS-Pn also yields 3*TIPS-Pn. These results show that multiple pathways produce the 3*TIPS-Pn state, so that OPV design strategies based on this system must utilize this triplet state for charge separation.

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