Unraveling the Fate of Host Excitons in Host-Guest Phosphorescent Organic Light-Emitting Diodes

Zhu, Tianyu; Van Voorhis, Troy

doi:10.1021/acs.jpcc.9b02820

Title: Unraveling the Fate of Host Excitons in Host-Guest Phosphorescent Organic Light-Emitting Diodes

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Abstract

Understanding energy and charge transfer mechanisms in host-guest systems is crucial for improving performance of organic light-emitting diodes (OLEDs), but it presents a theoretical challenge due to disordered molecular environment. Here, we address the fate of excitons that form on the host in a BTDF-Ir(ppy)₃ phosphorescent OLED through a QM/MM simulation. Our results demonstrate that triplet host excitons can be harvested through efficient energy transfer to the T₁ state of the guest allowed by excellent spectral overlap. Detailed analysis of the guest absorption spectrum uncovers that high-lying guest singlet states play a critical role in utilizing singlet host excitons. Furthermore, we investigate the process where host excitons break up and reform on the guest, and show it is unfavored owing to the high energy barrier. This work thus reveals energy transfer is the primary quenching mechanism for host excitons and highlights strategies for better host-guest design.

Authors:

Zhu, Tianyu ^[1]; Van Voorhis, Troy ^[1]

Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Chemistry

Publication Date:: Fri Apr 05 00:00:00 EDT 2019

Research Org.:: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

Sponsoring Org.:: USDOE

OSTI Identifier:: 1505181

Grant/Contract Number:: FG02-07ER46474

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Physical Chemistry. C

Additional Journal Information:: Journal Volume: 123; Journal Issue: 16; Journal ID: ISSN 1932-7447

Publisher:: American Chemical Society

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE

Citation Formats


                    Zhu, Tianyu, and Van Voorhis, Troy. Unraveling the Fate of Host Excitons in Host-Guest Phosphorescent Organic Light-Emitting Diodes.  United States: N. p., 2019. 
Web.  doi:10.1021/acs.jpcc.9b02820.

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                    Zhu, Tianyu, & Van Voorhis, Troy. Unraveling the Fate of Host Excitons in Host-Guest Phosphorescent Organic Light-Emitting Diodes.  United States.  https://doi.org/10.1021/acs.jpcc.9b02820

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                    Zhu, Tianyu, and Van Voorhis, Troy. Fri .  
"Unraveling the Fate of Host Excitons in Host-Guest Phosphorescent Organic Light-Emitting Diodes".  United States.  https://doi.org/10.1021/acs.jpcc.9b02820.  https://www.osti.gov/servlets/purl/1505181.

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@article{osti_1505181,

  title        = {Unraveling the Fate of Host Excitons in Host-Guest Phosphorescent Organic Light-Emitting Diodes},

  author       = {Zhu, Tianyu and Van Voorhis, Troy},

  abstractNote = {Understanding energy and charge transfer mechanisms in host-guest systems is crucial for improving performance of organic light-emitting diodes (OLEDs), but it presents a theoretical challenge due to disordered molecular environment. Here, we address the fate of excitons that form on the host in a BTDF-Ir(ppy)3 phosphorescent OLED through a QM/MM simulation. Our results demonstrate that triplet host excitons can be harvested through efficient energy transfer to the T1 state of the guest allowed by excellent spectral overlap. Detailed analysis of the guest absorption spectrum uncovers that high-lying guest singlet states play a critical role in utilizing singlet host excitons. Furthermore, we investigate the process where host excitons break up and reform on the guest, and show it is unfavored owing to the high energy barrier. This work thus reveals energy transfer is the primary quenching mechanism for host excitons and highlights strategies for better host-guest design.},

  doi          = {10.1021/acs.jpcc.9b02820},

  journal      = {Journal of Physical Chemistry. C},

  number       = 16,

  volume       = 123,

  place        = {United States},

  year         = {Fri Apr 05 00:00:00 EDT 2019},

  month        = {Fri Apr 05 00:00:00 EDT 2019}

}

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https://doi.org/10.1021/acs.jpcc.9b02820

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