Wang Hui, Chen Jia-Xiong, Zhou Lu, Zhang Xi, Yu Jia, Wang Kai, Zhang Xiao-Hong
Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu 215123, P. R. China.
School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, Guangdong, 510006, P. R. China.
Mater Horiz. 2023 Jul 31;10(8):2997-3004. doi: 10.1039/d3mh00445g.
Deep-red/near-infrared (DR/NIR) organic light-emitting diodes (OLEDs) have attracted a great deal of attention due to their widespread application fields, such as night-vision devices, optical communication, and information-secured displays. However, most DR/NIR OLEDs show low electroluminescence efficiencies, hampering their applications. Herein, we constructed a high-performance DR/NIR thermally activated delayed fluorescence (TADF) emitter based on an advanced dual-locked triarylamine donor (D) unit. Promisingly, such a novel D segment brings numerous advantages: a larger stereoscopic architecture, an enhanced electron-donating ability, and a stiffer molecular structure. In view of these features, the newly developed emitter DCN-DSP shows redshifted emission, a narrowed Δ, an enhanced PLQY value and aggregation-induced emission (AIE) properties, which allows for effectively alleviating concentration quenching compared to the control compound using a conventional triarylamine derivative as D units. The DCN-DSP-based OLEDs with modulated doping concentrations exhibit champion EQEs of 36.2% at 660 nm, 26.1% at 676 nm and 21.3% at 716 nm, which are record-high efficiencies among all TADF OLEDs in the similar emission ranges. This work realizes the efficiency breakthrough of DR/NIR TADF OLEDs, and such a promising molecular design approach may inspire even better DR/NIR TADF emitters in the future.
深红色/近红外（DR/NIR）有机发光二极管（OLED）因其广泛的应用领域，如夜视设备、光通信和信息安全显示器，而备受关注。然而，大多数DR/NIR OLED的电致发光效率较低，这阻碍了它们的应用。在此，我们基于先进的双锁三芳基胺供体（D）单元构建了一种高性能的DR/NIR热激活延迟荧光（TADF）发射体。很有希望的是，这种新型的D片段带来了许多优点：更大的立体结构、增强的供电子能力和更刚性的分子结构。鉴于这些特性，新开发的发射体DCN-DSP表现出红移发射、变窄的Δ、增强的PLQY值和聚集诱导发光（AIE）特性，与使用传统三芳基胺衍生物作为D单元的对照化合物相比，这有效地减轻了浓度猝灭。基于DCN-DSP的具有调制掺杂浓度的OLED在660 nm处的最高外量子效率（EQE）为36.2%，在676 nm处为26.1%，在716 nm处为21.3%，这些是所有在类似发射范围内的TADF OLED中的创纪录高效率。这项工作实现了DR/NIR TADF OLED的效率突破，并且这种有前景的分子设计方法可能会在未来激发更好的DR/NIR TADF发射体。
