Fused‐Nonacyclic Multi‐Resonance Delayed Fluorescence Emitter Based on Ladder‐Thiaborin Exhibiting Narrowband Sky‐Blue Emission with Accelerated Reverse Intersystem Crossing. (9th August 2021)

• Record Type: Journal Article
• Authors: Nagata, Masakazu; Min, Hyukgi; Watanabe, Erika; Fukumoto, Hiroki; Mizuhata, Yoshiyuki; Tokitoh, Norihiro; Agou, Tomohiro; Yasuda, Takuma
• Is Part Of: Angewandte Chemie. Volume 133:Number 37(2021)
• Page Start: 20442
• Page End: 20447
• Publication Date: 2021-08-09
• Subjects: narrowband emission -- organic light-emitting diodes -- organoboron -- spin-orbit coupling -- thermally activated delayed fluorescence; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202108283
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: 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. Abstract : A nanographitic fused‐nonacyclic π‐system embedded with multiple boron, nitrogen, and sulfur atoms was developed as a narrowband sky‐blue delayed fluorescence emitter for organic light‐emitting diodes. A design concept for inducing a synergetic effect on the luminescence function by exquisite multi‐heteroatom hybridization is presented.