基于C3-对称的热激活的延迟光发射器的激发状态动态
Katrina Bergmann1, Zachary M Hudson1
1Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada, V6T 1Z1. zhudson@chem.ubc.ca.
Faraday discussions
|November 17, 2023
概括
具有C3对称性的他材料为高效的热激活延迟光提供快速的反向系统间交叉 (rISC) 速率. 然而,保持对称性并不能保证高三重状态密度,影响整体性能.
科学领域:
- 材料科学 材料科学 材料科学
- 光物理学的光学物理学
- 有机化学 有机化学
背景情况:
- 基于赫普他的材料对热激活延迟光 (TADF) 是有前途的,因为它们的小单元-三元能量差距,促进了快速反向系统间交叉 (rISC).
- 高发射者对称性还可以通过能量水平退化和状态密度增加来提高RISC速率.
研究的目的:
- 调查结合C3对称的heptazine核心对激发状态动态的影响.
- 评估TADF发射器中的分子对称性,激发状态定位和光物理性质之间的关系.
主要方法:
- 对四个C3对称的他发射器进行计算研究.
- 激发状态属性的分析,包括能量水平,对称性和电荷定位.
- 检查自旋轨道合和三重状态密度.
主要成果:
- 四个发射器中的两个保持了C3对称性,在肝素核上具有局部激发 (LE) 特性,防止激发状态几何变化.
- 尽管对称性,但在这些分子中观察到S1状态以下的三重状态的损失.
- 具有LE S1状态的他材料通过增强的旋转轨道合与低的三重状态来最大限度地提高RISC率.
结论:
- 保持C3对称性在他发射器中并不能本质上保证三重状态的高密度.
- 具有LE S1状态的基于赫普他的材料具有出色的光物理特性,包括高光发光量子产量和颜色纯度,由于高效的RISC.
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