Lin Hong, Ye Zeyuan, Xian Sijie, Chen Zhanxiang, Miao Jingsheng, Huang Zhongyan, Zhong Cheng, Gong Shaolong, Cao Xiaosong, Yang Chuluo
Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China.
College of Chemistry and Molecular Sciences, Hubei Key Laboratory on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, 430072, P. R. China.
Adv Mater. 2025 Jul;37(30):e2502459. doi: 10.1002/adma.202502459. Epub 2025 May 19.
Multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters hold great promise for high-resolution OLEDs, yet achieving both ultranarrow emission and efficient triplet utilization in the deep-blue region remains challenging. Here, a synergistic molecular design is reported that combines π-extension and heavy-atom incorporation to effectively reconcile the trade-off between color purity and fast reverse intersystem crossing (RISC). In this approach, π-extension narrows the emission bandwidth and reduces the singlet-triplet energy gap, while the strategic introduction of chalcogen atoms selectively enhances spin-orbit coupling with minimal impact on the emission spectrum. As a result, the new emitter exhibits a peak emission at 453 nm with an exceptionally narrow full width at half maximum (FWHM) of 17 nm and a high RISC rate constant of 3.0 × 10 s. When incorporated into a non-sensitized OLED, the emitter meets the European Broadcast Union (EBU) deep-blue standard with CIE coordinates as low as (0.140, 0.059), and sustains a brightness exceeding 30,000 cd m. Notably, the device achieves a record-high external quantum efficiency (EQE) of 40.5% with minimal roll-off-retaining 38.4% and 28.2% at 100 and 1,000 cd m, respectively-and attains a Blue Index (BI) of 422 cd A CIE . These findings highlight the effectiveness of our tactic in overcoming prior limitations where heavy-atom doping often compromises color purity, paving the way for next-generation emitters in advanced display and lighting applications.
多共振热激活延迟荧光（MR-TADF）发光体在高分辨率有机发光二极管（OLED）方面极具潜力，但在深蓝色区域实现超窄发射和高效三线态利用仍具有挑战性。在此，报道了一种协同分子设计，该设计结合了π-扩展和重原子引入，以有效协调色纯度和快速反向系间窜越（RISC）之间的权衡。在这种方法中，π-扩展缩小了发射带宽并减小了单重态-三重态能隙，而硫族原子的策略性引入选择性地增强了自旋-轨道耦合，同时对发射光谱的影响最小。结果，新型发光体在453nm处呈现峰值发射，半高宽（FWHM）异常窄，仅为17nm，RISC速率常数高达3.0×10 s。当将该发光体集成到非敏化OLED中时，其符合欧洲广播联盟（EBU）的深蓝色标准，CIE坐标低至（0.140, 0.059），并且亮度超过30,000 cd m。值得注意的是，该器件实现了创纪录的40.5%的高外量子效率（EQE），且效率滚降极小，在100和1,000 cd m时分别保持38.4%和28.2%，并获得了422 cd A CIE的蓝色指数（BI）。这些发现突出了我们策略在克服先前重原子掺杂常常损害色纯度的局限性方面的有效性，为先进显示和照明应用中的下一代发光体铺平了道路。
