题目： | Stable narrowband blue OLEDs by modulating frontier molecular orbital level |
作者： | Xiao-Chun Fan1,2#, Xun Tang2#*, Tong-Yuan-Zhang1, Shintaro Kohata2, Jia Yu1,3, Xian-Kai Chen1, Kai Wang1,4*, Takuji Hatakeyama5, Chihaya Adachi2,6* , Xiao-Hong Zhang1,3* |
单位： | 1Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, Jiangsu, China. 2Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Japan. 3Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, Jiangsu, China. 4Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu, China. 5Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, Japan. 6International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka, Japan. |
摘要： | Energy level alignment of frontier molecular orbital (FMO) is essential for controlling charge carrier and exciton dynamics in organic light-emitting diodes (OLEDs). However, multiple resonance (MR) emitters with exceptional narrowband luminescence typically suffer from inadequate FMO levels. Herein, a conventional blue MR prototype with a shallow highest occupied molecular orbital (HOMO) level of −5.32 eV is initially employed to reveal the charge carrier and exciton dynamics. Severe hole trapping by its shallow HOMO significantly hinders its transport. More importantly, trapped carriers induce direct exciton formation and recombination at MR emitters in a hyperfluorescent system, leading to triplet accumulation in MR emitters. To resolve these issues, a proof-of-concept wavefunction perturbation strategy is proposed by incorporating cyano motifs at peripheral sites of MR backbone to adjust the energy levels. This approach significantly shifts HOMOs of 0.36 and 0.51 eV without compromising colour purity. The derivative substituting meta-boron position (mCNDB) exhibits a pure-blue emission peaking at 459 nm with a narrow bandwidth of 13 nm. The detrimental carrier trapping effect is eliminated, enhancing external quantum efficiency to exceeding 23%, maintaining around 20% at 1000 cd m−2, and improving the device stability. |
影响因子： | 15.7 |
分区情况： | 一区 |
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责任编辑：郭佳