Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
Department of Chemistry, Kyonggi University, Suwon 16227, Republic of Korea.
Int J Mol Sci. 2023 Aug 2;24(15):12362. doi: 10.3390/ijms241512362.
Triplet harvesting processes are essential for enhancing efficiencies of fluorescent organic light-emitting diodes. Besides more conventional thermally activated delayed fluorescence and triplet-triplet annihilation, the hot exciton mechanism has been recently noticed because it helps reduce the efficiency roll-off and improve device stability. Hot exciton materials enable the conversion of triplet excitons to singlet ones via reverse inter-system crossing from high-lying triplet states and thereby the depopulation of long-lived triplet excitons that are prone to chemical and/or efficiency degradation. Although their anti-Kasha characteristics have not been clearly explained, numerous molecules with behaviors assigned to the hot exciton mechanism have been reported. Indeed, the related developments appear to have just passed the stage of infancy now, and there will likely be more roles that computational elucidations can play. With this perspective in mind, we review some selected experimental studies on the mechanism and the related designs and then on computational studies. On the computational side, we examine what has been found and what is still missing with regard to properly understanding this interesting mechanism. We further discuss potential future points of computational interests toward aiming for eventually presenting in silico design guides.
三重态俘获过程对于提高荧光有机发光二极管的效率至关重要。除了更传统的热激活延迟荧光和三重态-三重态湮灭之外，最近人们注意到了热激子机制，因为它有助于降低效率滚降并提高器件稳定性。热激子材料通过从高能三重态的反向系间窜越，将三重态激子转化为单重态激子，从而耗尽容易发生化学和/或效率降低的长寿命三重态激子。尽管它们的反 Kasha 特性尚未得到明确解释，但已有许多分子的行为被归为热激子机制。实际上，相关的发展似乎刚刚度过起步阶段，计算阐明可能会发挥更多作用。考虑到这一点，我们回顾了一些关于该机制的实验研究以及相关设计，然后回顾了计算研究。在计算方面，我们检查了在正确理解这一有趣机制方面已经发现了什么，以及仍然存在哪些缺失。我们进一步讨论了计算方面的潜在未来关注点，旨在最终提供基于计算机的设计指南。
