Deep‐Red/Near‐Infrared Delayed Fluorescence Luminophores Based on DipyridoPhenazine‐11,12‐Dicarbonitrile for High‐Performance OLEDs

Deep‐red (DR) and near‐infrared (NIR) organic light‐emitting diodes (OLEDs) based on purely organic materials hold great potential in various frontier applications, but purely organic DR/NIR materials are far from satisfactory. Herein, a series of tailor‐made delayed fluorescence luminophores compri...

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Bibliographic Details
Published in:Advanced optical materials 2023-07, Vol.11 (14)
Main Authors: Cai, Zheyi, Liu, Zhangshan, Wu, Xing, Guo, Jingjing, Ben Zhong Tang, Zhao, Zujin
Format: Article
Language:English
Subjects:
Dipoles
Doped films
Fluorescence
Materials science
Near infrared radiation
Optics
Organic light emitting diodes
Organic materials
Photoluminescence
Quantum efficiency
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Summary:Deep‐red (DR) and near‐infrared (NIR) organic light‐emitting diodes (OLEDs) based on purely organic materials hold great potential in various frontier applications, but purely organic DR/NIR materials are far from satisfactory. Herein, a series of tailor‐made delayed fluorescence luminophores comprised of electron‐withdrawing dipyrido[3,2‐a:2″,3″‐c]phenazine‐11,12‐dicarbonitrile and various electron‐donating triarylamines are developed, and their thermal and electrochemical stabilities, electronic structures, photophysical properties and electroluminescence (EL) performances are investigated. They exhibit strong NIR emissions (758−767 nm) in neat films and DR/NIR emissions (680−691 nm) with good photoluminescence quantum yields (48−60%) in doped films, and prefer ordered horizontal alignment with high horizontal dipole ratios of 82−90%, which are attributed to the hybrid transition components of excited states, extended molecular plane and intramolecular hydrogen‐bonding. Their non‐doped OLEDs emit purely NIR light peaking at 820−834 nm with maximum external quantum efficiencies (ηext,maxs) of 0.66−1.06%, and thier doped OLEDs radiate DR/NIR emissions peaking at 656−748 nm with superb ηext,maxs of 14.4–31.0%. They present even better EL performances in sensitized OLEDs, with DR emissions peaking at 648−656 nm and higher ηext,maxs of 29.7−32.9%. These state‐of‐the‐art EL performances demonstrate the great potential of the developed DR/NIR delayed fluorescence luminophores in practical application.
ISSN:2195-1071
DOI:10.1002/adom.202300404