Carbonyl‐ and Nitrogen‐Embedded Multi‐Resonance Emitter with Ultra‐Pure Green Emission and High Electroluminescence Efficiencies

• Published in: Angewandte Chemie International Edition 2024-01, Vol.63 (4), p.e202316710-n/a
• Main Authors: Liang, Lu, Qu, Cheng, Fan, Xiangyu, Ye, Kaiqi, Zhang, Yuewei, Zhang, Zuolun, Duan, Lian, Wang, Yue
• Format: Article
• Language: English
• Subjects: Carbonyl compounds; Carbonyls; Electroluminescence; Emission spectra; Emissions; Emitters; Fluorescence; Fused-Ring Compounds; Light emitting diodes; Multiple Resonance; Nitrogen; Organic Light-Emitting Diodes; Quantum efficiency; Resonance; Spectral emittance; Spectral Narrowing; Thermally Activated Delayed Fluorescence
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202316710

Multi‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters with narrow emission spectra have garnered significant attention in future organic light‐emitting diode (OLED) displays. However, current C=O/N‐embedded MR‐TADF systems still lack satisfactory performance in terms of electroluminescence bandwidths and external quantum efficiencies (EQEs). In this study, a C=O/N‐embedded green MR‐TADF emitter, featuring two acridone units incorporated in a sterically protected 11‐ring fused core skeleton, is successfully synthesized through finely controlling the reaction selectivity. The superior combination of multiple intramolecular fusion and steric wrapping strategies in the design of the emitter not only imparts an extremely narrow emission spectrum and a high fluorescence quantum yield to the emitter but also mitigates aggregation‐induced spectral broadening and fluorescence quenching. Therefore, the emitter exhibits leading green OLED performance among C=O/N‐based MR‐TADF systems, achieving an EQE of up to 37.2 %, a full width at half maximum of merely 0.11 eV (24 nm), and a Commission Internationale de l′Éclairage coordinate of (0.20, 0.73). This study marks a significant advance in the realization of ideal C=O/N‐based MR‐TADF emitters and holds profound implications for the design and synthesis of other MR‐TADF systems. A C=O/N‐embedded green multi‐resonance emitter, which features two acridone units incorporated in a sterically protected 11‐ring fused core skeleton, is designed and successfully synthesized. The emitter exhibits leading electroluminescent‐device performance among C=O/N‐based green‐emissive MR systems, achieving an external quantum efficiency of up to 37.2 %, a full width at half maximum of merely 0.11 eV (24 nm), and a color coordinate of (0.20, 0.73).