Toward a BT.2020 green emitter through a combined multiple resonance effect and multi-lock strategy

• Published in: Nature communications Vol. 13; no. 1; p. 4876
• Main Authors: Liu, Junyuan, Zhu, Yunhui, Tsuboi, Taiju, Deng, Chao, Lou, Weiwei, Wang, Dan, Liu, Tiangeng, Zhang, Qisheng
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19.08.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/1019/1020/1091; 639/624/1020/1091; Activated carbon; Boron; Chemical bonds; Color; Cyclohexane; Emitters; Fluorescence; Humanities and Social Sciences; Luminescence; multidisciplinary; Organic light emitting diodes; Phosphorescence; Quantum dots; Quantum efficiency; Resonance; Science; Science (multidisciplinary); Television; Vibrations
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-32607-3

Color-saturated green-emitting molecules with high Commission Internationale de L’Eclairage (CIE) y values have great potential applications for displays and imaging. Here, we linked the outer phenyl groups in multiple-resonance (MR)-type blue-emitting B (boron)-N (nitrogen) molecules through bonding and spiro-carbon bridges, resulting in rigid green emitters with thermally activated delayed fluorescence. The MR effect and multiple interlocking strategy greatly suppressed the high-frequency vibrations in the molecules, which emit green light with a full-width at half-maximum of 14 nm and a CIE y value of 0.77 in cyclohexane. These were the purest green molecules with quantum efficiency and color purity that were comparable with current best quantum dots. Doping these emitters into a traditional green-emitting phosphorescence organic light-emitting diode (OLED) endowed the device with a Broadcast Service Television 2020 color-gamut, 50% improved external quantum efficiency, and an extremely high luminescence of 5.1 × 10 5  cd/m 2 , making it the greenest and brightest OLED ever reported. The authors combine multiple resonance effect and multi-lock strategy to dope green-emitting thermally activated delayed fluorescent molecules into green-emitting phosphorescence OLEDs by endowing the device with a Broadcast Service Television 2020 color-gamut, 50% improved EQE, and a high luminescence of half a million nits.