Design and synthesis of fast kRISC MR-TADF emitters: merge of cycloparaphenylene materials and B,O doped MR-TADF emitters (CPP-MR-TADF)

有机发光二极管（OLED）如今以显示屏的形式在移动的电话和智能手表中无处不在。虽然这项技术已经商业化，但仍有不足之处。例如，OLED使用稀有的贵金属如铱作为显示器的红色和绿色像素的发射体，使得目前形式的技术不可持续。2015年首次推出的多共振热激活延迟荧光（MR-TADF）发射体是有机化合物，可以生产与磷光OLED相当的效率和色点的OLED，但可持续发展。然而，具有MR-TADF材料的OLED目前遭受与缓慢的反向系间穿越速率（kRISC）、导致发射猝灭的强分子间相互作用/聚集以及差的电荷传输性质相关的太高的效率滚降。该项目提出了一类新的发光材料的开发，其将MR-TADF发射器和环对苯（CPP）材料的方面结合在一起。CPP是具有圆柱形几何形状的纯烃有机半导体，其强烈限制了固态中的分子间相互作用。这个基本的建议探讨了理论建模，合成，和光电特性的混合CPP-MR-TADF材料作为OLED的潜在发射器的家庭。提出的多学科策略旨在提供一种广受欢迎的解决方案，以增加MR-TADF材料中的kRISC，同时还解决发射层中的电荷传输问题以及这些分子不期望地聚集的倾向。

Organic light-emitting diodes (OLEDs) are nowadays omnipresent in the form of display screens in mobile phones and smartwatches. Although already commercialized, this technology still possesses shortcomings. For instance, OLEDs use scarce noble metals like iridium as emitters for the red and green pixels of the display, making the technology in its present form not sustainable. Introduced for the first time in 2015, multiresonant thermally activated delayed fluorescence (MR-TADF) emitters, which are organic compounds, allow to produce OLEDs at comparable efficiency and color point to phosphorescent OLEDs, but are sustainable. However, OLEDs with MR-TADF materials presently suffer from a too high efficiency roll-off related to the slow reverse intersystem crossing rate (kRISC), strong intermolecular interactions/aggregation that cause emission quenching, and poor charge transport properties. This project proposes the development of a new class of luminescent materials that brings together facets of MR-TADF emitters and cycloparaphenylene (CPP) materials. CPPs are pure hydrocarbon organic semiconductors that possess a cylindrical geometry, which strongly limits intermolecular interactions in the solid state. This fundamental proposal explores the theoretical modelling, synthesis, and optoelectronic characterization of a family of hybrid CPP-MR-TADF materials as potential emitters for OLEDs. The proposed multidisciplinary strategy aims to provide a sought-after solution to increasing kRISC in MR-TADF materials while also addressing issues of charge transport in the emissive layer and the propensity for these molecules to undesirably aggregate.