The photophysical analysis of thermally activated delayed fluorescence (TADF) materials has become instrumental for providing insights into their stability and performance, which is not only relevant for organic light-emitting diodes but also for other applications such as sensing, imaging, and photocatalysis. Thus, a deeper understanding of the photophysics underpinning the TADF mechanism is required to push materials design further. Previously reported analyses in the literature of the kinetics of the various processes occurring in a TADF material rely on several a priori assumptions to estimate the rate constants for forward and reverse intersystem crossing. In this report, we demonstrate a method to determine these rate constants using a three-state model together with a steady-state approximation and, importantly, no additional assumptions. Further, we derive the exact rate equations, greatly facilitating a comparison of the TADF properties of structurally diverse emitters and providing a comprehensive understanding of the photophysics of these systems.

中文翻译：

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热活化延迟荧光材料动力学分析的精确解

热激活延迟荧光 (TADF) 材料的光物理分析已成为深入了解其稳定性和性能的工具，这不仅与有机发光二极管相关，而且与传感、成像和光催化等其他应用相关。因此，需要更深入地了解支撑 TADF 机制的光物理学，以进一步推动材料设计。先前在文献中报道的 TADF 材料中发生的各种过程的动力学分析依赖于几个先验假设来估计正向和反向系统间交叉的速率常数。在本报告中，我们展示了一种使用三态模型和稳态近似来确定这些速率常数的方法，重要的是，没有额外的假设。