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Fused‐Nonacyclic Multi‐Resonance Delayed Fluorescence Emitter Based on Ladder‐Thiaborin Exhibiting Narrowband Sky‐Blue Emission with Accelerated Reverse Intersystem Crossing
Author(s) -
Nagata Masakazu,
Min Hyukgi,
Watanabe Erika,
Fukumoto Hiroki,
Mizuhata Yoshiyuki,
Tokitoh Norihiro,
Agou Tomohiro,
Yasuda Takuma
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.202108283
Subject(s) - intersystem crossing , electroluminescence , oled , common emitter , photoluminescence , quantum yield , materials science , optoelectronics , quantum efficiency , fluorescence , singlet state , narrowband , excited state , photochemistry , chemistry , optics , atomic physics , nanotechnology , physics , layer (electronics)
Developing organic luminophores with unique capability of strong narrowband emission is both crucial and challenging for the further advancement of organic light‐emitting diodes (OLEDs). Herein, a nanographitic fused‐nonacyclic π‐system ( BSBS‐N1 ), which was strategically embedded with multiple boron, nitrogen, and sulfur atoms, was developed as a new multi‐resonance thermally activated delayed fluorescence (MR‐TADF) emitter. Narrowband sky‐blue emission with a peak at 478 nm, full width at half maximum of 24 nm, and photoluminescence quantum yield of 89 % was obtained with BSBS‐N1 . Additionally, the spin‐orbit coupling was enhanced by incorporating two sulfur atoms, thereby facilitating the spin‐flipping process between the excited triplet and singlet states. OLEDs based on BSBS‐N1 as a sky‐blue MR‐TADF emitter achieved a high maximum external electroluminescence quantum efficiency of 21.0 %, with improved efficiency roll‐off.