Wu Shao-Jie, Fu Xi-Feng, Zhang Dong-Hai, Sun Yu-Fu, Lu Xin, Lin Fu-Lin, Meng Lingyi, Chen Xu-Lin, Lu Can-Zhong
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, China.
Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials, Xiamen Institute of Rare Earth Materials, Haixi Institutes, Chinese Academy of Sciences, Xiamen, Fujian, 361021, China.
Adv Mater. 2024 Jun;36(26):e2401724. doi: 10.1002/adma.202401724. Epub 2024 Apr 19.
Simultaneously achieving a high photoluminescence quantum yield (PLQY), ultrashort exciton lifetime, and suppressed concentration quenching in thermally activated delayed fluorescence (TADF) materials is desirable yet challenging. Here, a novel acceptor-donor-acceptor type TADF emitter, namely, 2BO-sQA, wherein two oxygen-bridged triarylboron (BO) acceptors are arranged with cofacial alignment and positioned nearly orthogonal to the rigid dispirofluorene-quinolinoacridine (sQA) donor is reported. This molecular design enables the compound to achieve highly efficient (PLQYs up to 99%) and short-lived (nanosecond-scale) blue TADF with effectively suppressed concentration quenching in films. Consequently, the doped organic light-emitting diodes (OLEDs) base on 2BO-sQA achieve exceptional electroluminescence performance across a broad range of doping concentrations, maintaining maximum external quantum efficiencies (EQEs) at over 30% for doping concentrations ranging from 10 to 70 wt%. Remarkably, the nondoped blue OLED achieves a record-high maximum EQE of 26.6% with a small efficiency roll-off of 14.0% at 1000 candelas per square meter. By using 2BO-sQA as the sensitizer for the multiresonance TADF emitter ν-DABNA, TADF-sensitized fluorescence OLEDs achieve high-efficiency deep-blue emission. These results demonstrate the feasibility of this molecular design in developing TADF emitters with high efficiency, ultrashort exciton lifetime, and minimal concentration quenching.
在热激活延迟荧光（TADF）材料中同时实现高光致发光量子产率（PLQY）、超短激子寿命和抑制浓度猝灭是理想的，但具有挑战性。在此，报道了一种新型的受体-供体-受体型TADF发射体，即2BO-sQA，其中两个氧桥连三芳基硼（BO）受体以共面排列方式排列，且与刚性双螺芴-喹啉吖啶（sQA）供体几乎正交定位。这种分子设计使该化合物能够实现高效（PLQY高达99%）且短寿命（纳秒级）的蓝色TADF，同时有效抑制薄膜中的浓度猝灭。因此，基于2BO-sQA的掺杂有机发光二极管（OLED）在广泛的掺杂浓度范围内均表现出优异的电致发光性能，对于10至70 wt%的掺杂浓度，最大外量子效率（EQE）保持在30%以上。值得注意的是，未掺杂的蓝色OLED在每平方米1000坎德拉时实现了创纪录的26.6%的最大EQE，效率滚降仅为14.0%。通过使用2BO-sQA作为多共振TADF发射体ν-DABNA的敏化剂，TADF敏化荧光OLED实现了高效的深蓝色发射。这些结果证明了这种分子设计在开发具有高效率、超短激子寿命和最小浓度猝灭的TADF发射体方面的可行性。
