Zang Chunxiu, Liu Shihao, Xu Mengxin, Wang Ruifang, Cao Chen, Zhu Zelin, Zhang Jiaming, Wang Hui, Zhang Letian, Xie Wenfa, Lee Chun-Sing
State key Laboratory of Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, 130012, Changchun, China.
Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, 999077, Hong Kong SAR, China.
Light Sci Appl. 2021 Jun 3;10(1):116. doi: 10.1038/s41377-021-00559-w.
Resonance interaction between a molecular transition and a confined electromagnetic field can lead to weak or strong light-matter coupling. Considering the substantial exciton-phonon coupling in thermally activated delayed fluorescence (TADF) materials, it is thus interesting to explore whether weak light-matter coupling can be used to redistribute optical density of states and to change the rate of radiative decay. Here, we demonstrate that the emission distribution of TADF emitters can be reshaped and narrowed in a top-emitting organic light-emitting device (OLED) with a weakly coupled microcavity. The Purcell effect of weak microcavity is found to be different for TADF emitters with different molecular orientations. We demonstrate that radiative rates of the TADF emitters with vertical orientation can be substantial increased in weakly coupled organic microcavity. These observations can enhance external quantum efficiencies, reduce efficiency roll-off, and improve color-purities of TADF OLEDs, especially for emitters without highly horizontal orientation.
分子跃迁与受限电磁场之间的共振相互作用可导致弱或强光-物质耦合。考虑到热激活延迟荧光（TADF）材料中存在大量的激子-声子耦合，因此探索弱光-物质耦合是否可用于重新分配态密度并改变辐射衰减速率是很有意思的。在此，我们证明，在具有弱耦合微腔的顶发射有机发光二极管（OLED）中，TADF发光体的发射分布可以被重塑并变窄。对于具有不同分子取向的TADF发光体，发现弱微腔的珀塞尔效应是不同的。我们证明，在弱耦合有机微腔中，垂直取向的TADF发光体的辐射速率可大幅提高。这些观察结果可提高外部量子效率，降低效率滚降，并改善TADF OLED的色纯度，特别是对于没有高度水平取向的发光体。
