Hydrogen bond-modulated molecular packing and its applications in high-performance non-doped organic electroluminescence

• Published in: Materials horizons 2020, Vol.7 (1), p.2734-274
• Main Authors: Shi, Yizhong, Wang, Kai, Tsuchiya, Youichi, Liu, Wei, Komino, Takeshi, Fan, Xiaochun, Sun, Dianming, Dai, Gaole, Chen, Jiaxiong, Zhang, Ming, Zheng, Caijun, Xiong, Shiyun, Ou, Xuemei, Yu, Jia, Jie, Jiansheng, Lee, Chun-Sing, Adachi, Chihaya, Zhang, Xiaohong
• Format: Article
• Language: English
• Subjects: Chemical bonds; Crystallography; Electroluminescence; Emitters; Excitons; Fluorescence; Horizontal orientation; Hydrogen bonding; Hydrogen bonds; Organic light emitting diodes; Quantum efficiency; Quenching; Supramolecular frameworks
• ISSN: 2051-6347; 2051-6355
• DOI: 10.1039/d0mh00952k

Exploiting high-performance non-doped organic light-emitting diodes (OLEDs) is a step towards future commercial application requirements, but great challenges remain due to quenching related to intermolecular triplet interaction. In this work, a novel strategy of exploiting high-performance non-doped electroluminescence via tuning intermolecular hydrogen bonding is demonstrated. Suitable intermolecular hydrogen bonding enables formation of a 3D supramolecular framework, which not only evidently restricts the nonradiative process and suppresses the triplet exciton quenching caused by π-π stacking of triplets, but also favors the horizontal molecular orientations especially in their non-doped states. The non-doped OLED based on the thermally activated delayed fluorescence emitter m TPy-PXZ with such suitable intermolecular hydrogen bonds exhibits the state-of-the-art performance with maximum external quantum efficiency of up to 23.6% with only 7.2% roll-off at 1000 cd m −2 . Moreover, it is the first report that the performance of an OLED with a non-doped emitting layer can surpass its corresponding optimized doped device. It is believed that this hydrogen bond-modulated mechanism can not only provide a new pathway for designing emitters for high-performance non-doped organic electroluminescence, but also has great potential in other solid-state luminescence applications. Suitable intermolecular hydrogen bonding enables the formation of a fixed 3D supramolecular framework and suppresses the exciton nonradiative decays and quenching.