High‐Performance Solution‐Processed Nondoped Circularly Polarized OLEDs with Chiral Triptycene Scaffold‐Based TADF Emitters Realizing Over 20% External Quantum Efficiency
High‐Performance Solution‐Processed Nondoped Circularly Polarized OLEDs with Chiral Triptycene Scaffold‐Based TADF Emitters Realizing Over 20% External Quantum Efficiency
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DOI：
10.1002/adfm.202106418
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发表时间：
2021-09
影响因子：
19
通讯作者：
Yin‐Feng Wang;Meng Li;Jin‐Ming Teng;He‐Ye Zhou;Chuan-feng Chen
中科院分区：
文献类型：
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作者：
Yin‐Feng Wang;Meng Li;Jin‐Ming Teng;He‐Ye Zhou;Chuan-feng Chen
近年来，利用热激活延迟荧光（TADF）发光体制备的圆偏振有机发光二极管（CP-OLED）得到了迅速发展。然而，大多数器件都是通过真空沉积技术制造的，开发高效的溶液处理CP-OLED，特别是非掺杂器件，仍然是一个挑战。本文合成了一对基于三蝶烯的对映体（S，S）-/（R，R）-TpAc-TRZ。这种新型的手性三蝶烯对映异构体骨架避免了它们的分子间π-π堆积，这有利于它们的聚集诱导发射特性和固态下85%的高光致发光量子产率。此外，三蝶烯类对映体表现出有效的TADF活性，具有0.03 eV的小单重态-三重态能隙（ΔEST）和1.1 µs的延迟荧光寿命，以及具有不对称因子的强圆偏振发光（|GPL|约1.9 × 10−3。基于（S，S）-/（R，R）-TpAc-TRZ的溶液处理的非掺杂CP-OLED不仅显示出明显的圆偏振电致发光信号，其gEL值分别为+1.5 × 10−3和-2.0 × 10−3，而且还实现了高效率，其外量子效率、电流效率和功率效率分别高达25.5%、88.6 cd A−1和95.9 lm W−1。
Recently, circularly polarized organic light‐emitting diodes (CP‐OLEDs) fabricated with thermally activated delayed fluorescence (TADF) emitters are developed rapidly. However, most devices are fabricated by vacuum deposition technology, and developing efficient solution‐processed CP‐OLEDs, especially nondoped devices, is still a challenge. Herein, a pair of triptycene‐based enantiomers, (S,S)‐/(R,R)‐TpAc‐TRZ, are synthesized. The novel chiral triptycene scaffold of enantiomers avoids their intermolecular π–π stacking, which is conducive to their aggregation‐induced emission characteristics and high photoluminescence quantum yield of 85% in the solid state. Moreover, the triptycene‐based enantiomers exhibit efficient TADF activities with a small singlet‐triplet energy gap (ΔEST) of 0.03 eV and delayed fluorescence lifetime of 1.1 µs, as well as intense circularly polarized luminescence with dissymmetry factors (|gPL|) of about 1.9 × 10−3. The solution‐processed nondoped CP‐OLEDs based on (S,S)‐/(R,R)‐TpAc‐TRZ not only display obvious circularly polarized electroluminescence signals with gEL values of +1.5 × 10−3 and −2.0 × 10−3, respectively, but also achieve high efficiencies with external quantum, current, and power efficiency up to 25.5%, 88.6 cd A−1, and 95.9 lm W−1, respectively.