重原子参与的离子-π+相互作用构建纯有机室温磷光材料及其应用研究

Pure organic room temperature phosphorescence (RTP) materials have drawn extensive attention because of their unique advantages and broad application prospect in the fields of display, illumination, optoelectronics, optical storage, light-catalysis, anti-counterfeiting, sensors and bioimaging. However, developing persistent and efficient pure organic RTP materials is extremely difficult because of inefficient intersystem crossing (ISC) caused by weak spin-orbit coupling and the rapid rate of nonradiative decay. Heavy-atom effects introduced to phosphor by.covalent bond is an traditional and efficient method to enhance phosphorescent quantum yield, but the tuning of their RTP behavior at the molecular level requires careful structure tailoring, which leads to tedious synthetic and purification tasks. In this project, we will synthesize organic salts with AIE-active using noncovalent (anion-π+) interactions. With heavy halogen ions as counterion introduced into organic salt luminogens by simple ion exchange method, heavy-atom-participated anion-π+ interactions can be formed and furthrt used to construct RTP-active organic salt compounds. This project will deepen theoretical understanding of RTP and demonstrate a promising strategy of heavy-atom-participated anion-π+ interactions to guide the design of materials with pure organic RTP. Under certain condition, organic single-molecule white light emitters will be realized by simply tuning the aggregation modes, the distance between counterions and π+ or ratio of different counterions of organic salts with RTP-active. The target localization ability of organic salt molecules with water solubility will contribute to bioimaging application of RTP materials to achieving high-resolution bioimaging without short-lived autofluorescence.

纯有机室温磷光材料因其在显示、照明、防伪、生物成像等领域具有独特的应用优势和广阔的应用前景而受到了人们的广泛关注，然而到目前为止，合成高效纯有机室温磷光材料仍极具挑战。传统的通过共价键引入重原子效应是提高磷光量子产率有效途径之一，但是合成复杂且不易改变重原子。本申请拟合成几类含有非共价（阴离子-π+）相互作用的新型有机盐分子，经简单的离子交换法将重原子作为对阴离子引入到有机盐发光分子中，在重原子参与的阴离子-π+相互作用下构建纯有机室温磷光，为纯有机室温磷光的设计合成提供新的思路。在特定条件下，通过调控有机盐分子的堆积方式、对阴离子与π+离子之间的距离或改变分子中不同对阴离子的比例实现对有机盐发光波长的调控，进而构建纯有机单分子白光器件。利用有机盐分子的水溶性和正电荷对细胞器的靶向定位能力，将有机室温磷光材料应用于细胞成像，实现无背景干扰的高分辨细胞器靶向成像。

纯有机室温磷光材料因其在显示、照明、防伪、生物成像等领域具有独特的应用优势和广阔的应用前景而受到了人们的广泛关注，然而到目前为止，合成高效纯有机室温磷光材料仍极具挑战。本项目主要开展了两方面的的工作：.1. 合成了几类含有阴离子-π+相互作用的新型有机盐分子，经简单的离子交换法将重原子作为对阴离子引入到有机盐发光分子中，在重原子参与的阴离子-π+相互作用下构建纯有机室温磷光。在特定条件下，通过调控有机盐分子的堆积方式、对阴离子与π+离子之间的距离或改变分子中不同对阴离子的比例实现了有机盐发光波长的调控，进而成功构建了纯有机单分子白光器件。.2. 将课题进一步拓展到其他的非共价键相互作用，合成了含有氢键相互作用和推拉电子效应的有机小分子，通过增强分子内氢键相互作用，可以有效调控分子的平面性、分子间相互作用及堆积方式，帮助分子间电子耦合。通过引入杂原子和重原子，分子内的推拉电子效应可显著增强，并进一步增强分子内电荷转移，改变激发态的轨道跃迁构型，促使系间窜越和旋轨耦合常数的提升。故而，含有双重分子内氢键和最强推拉电子效应的 CzPM和CzPMBr表现出超长的磷光寿命和最高的磷光量子效率。这种设计策略将大大拓宽超长纯有机室温磷光材料的设计思路。