From phosphorescence to delayed fluorescence in one step: tuning photophysical properties by quaternisation of an sp 2 -hybridised nitrogen atom
From phosphorescence to delayed fluorescence in one step: tuning photophysical properties by quaternisation of an sp 2 -hybridised nitrogen atom
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一步从磷光到延迟荧光：通过 sp 2 杂化氮原子的季铵化调节光物理性质
DOI：
10.1039/d2tc01737g
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发表时间：
2022
影响因子：
6.4
通讯作者：
Klimash A
中科院分区：
文献类型：
--
作者：
Klimash A
控制有机化合物的延迟发射是开发新的显示技术以及在传感和荧光显微镜中使用有机发射体的一个重要因素。特别是，有必要了解室温磷光和热激活延迟荧光的现象是如何相交的。在这里，我们发现延迟荧光可以通过sp2杂化杂环氮的季铵化在室温磷光发射体中被激活。此外，通过将咔唑供体在环氮原子的元位或对位定位，结构和空间影响结合起来，将延迟荧光的起源从三重态-三重态湮灭调整为热激活的延迟荧光。至关重要的是，氮的季铵化为我们提供了以可预测的方式微调单线态和三重态的手段，揭示了磷光和延迟荧光之间的交集，并打破了有利于延迟荧光的平衡。
Control of the delayed emission of organic compounds is an important factor in the development of new display technology and for the emerging use of organic emitters in sensing and fluorescence microscopy. In particular, there is a need to understand how the phenomena of room-temperature phosphorescence and thermally activated delayed fluorescence intersect. Here, we show that delayed fluorescence can be activated in room temperature phosphorescence emitters by quaternising the sp2-hybridised heterocyclic nitrogens. Furthermore by judicious positioning of a carbazole donor in the meta- or para-position with respect to the ring nitrogen atom, structural and sterical influences combine to tune the origins of the delayed fluorescence from triplet–triplet annihilation to thermally activated delayed fluorescence. Crucially, the quaternisation of nitrogen provides us with the means to fine-tune singlet and triplet states in a predictable manner, uncover the intersection between phosphorescence and delayed fluorescence and tip the balance in favour of delayed fluorescence.