开发高效的近红外光活性材料是发展近红外电致发光器件的根本和关键。热激发延迟荧光（Thermally Activated Delayed Fluorescence, TADF）材料与器件可以实现高达100%的内量子效率，在提升器件效率方面有突出优势。然而，近红外TADF材料的发展尚处于起步阶段，如何兼顾高效的近红外发射和低的单三线态能级差是制约其发展的关键科学问题。对此，本项目提出基于芳香膦氧基团构建高效的近红外TADF材料。拟利用芳香膦氧基团适中的吸电子诱导作用调节分子内推拉电子效应，增强前线轨道分离以降低单三线态能级差，提升TADF性能；再结合其大位阻效应，增强分子构型的扭曲，控制分子极性及分子间相互作用以抑制猝灭效应；最终实现高效和高色纯度的近红外TADF发射。本项目旨在开发一批性能优异的芳香膦氧类近红外TADF材料与器件，形成一系列具有自身特色和自主知识产权的新材料、新技术和新方法。

High efficient near-infrared (NIR) materials are the base and key of developing NIR electroluminescent devices. Thermally activated delayed fluorescence (TADF) materials and devices can realize the internal quantum efficiency up to 100%, which shows outstanding advantage on improving electroluminescent efficiency. However, the development of NIR TADF materials is still in its infancy, with key issue of how to balance the highly efficiency NIR emission and small singlet-triplet splitting. In this regard, this project proposes constructing NIR TADF materials based on aryl phosphine oxide (APO). It plans to use the appropriate electron-withdrawing effect of APO to regulate intramolecular charge transfer, enhance frontier molecular orbital separation and reduce singlet-triplet splitting, leading to the improvement of TADF property. Meanwhile, the large steric hindrance of APO will be utilized to enhance molecular configuration twist, control molecular polarity and intermolecular interaction, and suppress quenching effect. As a result, high efficient NIR TADF emission with high color purity will be realized. The main objective of this project is to exploit aryl phosphine oxide based NIR TADF materials with excellent performance, which will form signature features and proprietary intellectual property rights in the new materials, technologies and methods.