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Highly Efficient Near‐Infrared Delayed Fluorescence Organic Light Emitting Diodes Using a Phenanthrene‐Based Charge‐Transfer Compound
Author(s) -
Wang Shipan,
Yan Xianju,
Cheng Zong,
Zhang Hongyu,
Liu Yu,
Wang Yue
Publication year - 2015
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.201506687
Subject(s) - oled , quantum efficiency , phosphorescence , triphenylamine , electroluminescence , phenanthrene , materials science , phosphorescent organic light emitting diode , fluorescence , photochemistry , optoelectronics , acceptor , chemistry , optics , nanotechnology , organic chemistry , physics , layer (electronics) , condensed matter physics
Significant efforts have been made to develop high‐efficiency organic light‐emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) emitters with blue, green, yellow, and orange–red colors. However, efficient TADF materials with colors ranging from red, to deep‐red, to near‐infrared (NIR) have been rarely reported owing to the difficulty in molecular design. Herein, we report the first NIR TADF molecule TPA‐DCPP (TPA=triphenylamine; DCPP=2,3‐dicyanopyrazino phenanthrene) which has a small singlet–triplet splitting (Δ E ST ) of 0.13 eV. Its nondoped OLED device exhibits a maximum external quantum efficiency (EQE) of 2.1 % with a Commission International de L′Éclairage (CIE) coordinate of (0.70, 0.29). Moreover, an extremely high EQE of nearly 10 % with an emission band at λ =668 nm has been achieved in the doped device, which is comparable to the most‐efficient deep‐red/NIR phosphorescent OLEDs with similar electroluminescent spectra.