Modulation of Thermally Activated Delayed Fluorescence in Waterborne Polyurethanes via Charge‐Transfer Effect
作者:Zongren Li、Tao Wang、Dong Xu、Jie Zuo、Xinyu Li、Zhiwei Li、Fei Xu、Xingyuan Zhang
DOI:10.1002/asia.201900423
日期:2019.7
several waterborne polyurethanes (WPUs) with efficient thermally activated delayed fluorescence (TADF) via serving charge‐transfer (CT) states as a mediate bridge between singlet and triplet states to boost reverse intersystem crossing (RISC). By tuning substituents of diphenyl sulfone (DS), we found that O,O′‐ and S,S′‐substituted DS covalently incorporated in WPUs solely show typical fluorescence emission
在这里,我们设计了几种具有高效热活化延迟荧光(TADF)的水性聚氨酯(WPU),它们通过将电荷转移(CT)状态用作单重态和三重态之间的中介桥来增强反向系统间交叉(RISC)。通过调节二苯砜(DS)的取代基,我们发现共价掺入WPU中的O,O'-和S,S'-取代的DS仅显示典型的荧光发射,其寿命在纳秒范围内。有趣的是,TADF是通过用氮原子取代取代基而出现的,即使在单重态和三重态之间的能隙,其寿命在空气和真空中的寿命分别高达≈10微秒和≈1毫秒(ΔE ST)对于生成TADF仍然很大。为了解释这种现象,提出了一种基于CT状态和3(n-π*)接收器状态的能级模式。通过对CT状态的合理调制,可以对ΔE ST进行调谐,从而使基于TADF的材料适用于多种应用。