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

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 T 1 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:
 [1];  [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Chemistry
Publication Date:
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 Name: Journal of Physical Chemistry. C; 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.
Zhu, Tianyu, & Van Voorhis, Troy. Unraveling the Fate of Host Excitons in Host-Guest Phosphorescent Organic Light-Emitting Diodes. United States. doi:10.1021/acs.jpcc.9b02820.
Zhu, Tianyu, and Van Voorhis, Troy. Fri . "Unraveling the Fate of Host Excitons in Host-Guest Phosphorescent Organic Light-Emitting Diodes". United States. doi:10.1021/acs.jpcc.9b02820.
@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 = ,
volume = ,
place = {United States},
year = {2019},
month = {4}
}

Journal Article:
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This content will become publicly available on April 5, 2020
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