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Highly Efficient Near‐Infrared Electrofluorescence from a Thermally Activated Delayed Fluorescence Molecule
Author(s) -
Balijapalli Umamahesh,
Nagata Ryo,
Yamada Nishiki,
Nakanotani Hajime,
Tanaka Masaki,
D'Aléo Anthony,
Placide Virginie,
Mamada Masashi,
Tsuchiya Youichi,
Adachi Chihaya
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202016089
Subject(s) - oled , materials science , optoelectronics , common emitter , electroluminescence , quantum efficiency , fluorescence , quantum yield , fluorophore , near infrared spectroscopy , photoluminescence , diode , optics , nanotechnology , physics , layer (electronics)
Near‐IR organic light‐emitting diodes (NIR‐OLEDs) are potential light‐sources for various sensing applications as OLEDs have unique features such as ultra‐flexibility and low‐cost fabrication. However, the low external electroluminescence (EL) quantum efficiency (EQE) of NIR‐OLEDs is a critical obstacle for potential applications. Here, we demonstrate a highly efficient NIR emitter with thermally activated delayed fluorescence (TADF) and its application to NIR‐OLEDs. The NIR‐TADF emitter, TPA‐PZTCN, has a high photoluminescence quantum yield of over 40 % with a peak wavelength at 729 nm even in a highly doped co‐deposited film. The EL peak wavelength of the NIR‐OLED is 734 nm with an EQE of 13.4 %, unprecedented among rare‐metal‐free NIR‐OLEDs in this spectral range. TPA‐PZTCN can sensitize a deeper NIR fluorophore to achieve a peak wavelength of approximately 900 nm, resulting in an EQE of over 1 % in a TADF‐sensitized NIR‐OLED with high operational device durability (LT 95 >600 h.).