基于C-H键直接芳基化反应模块化合成唑类发光材料及其热激活延迟荧光性能研究

Organic light-emitting materials are the critical factors for the performance of organic light emitting diodes (OLEDs). Therefore, related researches about molecular designs, synthetic methods and structure-function relationships are hot topics in the fields of OLEDs. The azole-based molecules usually exhibit excellent luminescent properties and have great potential in the high-performance OLEDs. In particular, the development of azoles based on thermally activated delayed fluorescence (TADF) offers a new avenue for OLEDs with theoretically 100% internal quantum efficiency. However, the research of TADF-based azoles is still in its infancy and meets some challenges, including lack of species diversity, difficulties in structural modifications and unclearness of structure-function relationship. Aiming at solving the above problems, a serious of structure-diversified azole-based emitting molecules were carefully designed and modularly synthesized through C–H direct arylation in this project. Then, optical properties of these molecules will be investigated, and molecular design will be adjusted rationally according to the structure-function relationships. Thereafter, the physical model “molecular design – modular synthesis – properties characterization” can be gradually established. Finally, abundant study samples as well as accurate experimental data can be provided for the design, luminescence mechanism study and further applications of high-performance luminescent materials. Meanwhile, it would be beneficial to promote the fundamental research as well as industrialization of related materials.

有机发光材料是决定有机电致发光器件（OLED）性能的关键因素，因此与之相关的分子设计、合成方法和构效关系等研究工作均为当前OLED领域的重点研究方向。热激活延迟荧光型唑类发光材料在高性能OLED领域具有巨大发展潜力，针对其当前面临的分子种类单一和构效关系不明确等难题，本申请拟选用C–H键直接芳基化反应为主要合成手段，选择性可控地对唑杂环（或联唑杂环）骨架进行芳基化修饰，模块化合成一系列结构多样化的唑类发光分子，进而测试材料性能，分析其构效关系并反馈于分子设计，逐步完善“分子设计-模块化合成-材料性能”物理模型。最终可为高性能发光材料分子设计、发光机制研究以及相关材料应用开发提供丰富的研究样本和切实的实验数据，有助于加快相关材料的基础研究和产业化进程。

发展新型的高性能有机发光分子是当前材料科学领域中的重要研究方向之一，其中以含氮杂环为核心的发光材料凭借其优异的性能在有机发光材料领域占有举足轻重的地位，尤其是基于热激活延迟荧光（TADF）机制的含氮杂环分子的研究更是为高发光效率有机发光显示器件（OLED）提供了新的发展思路。但是在实际研究中仍面临着材料分子种类单一、构效关系不明确以及合成路线较为冗繁等难题，本课题以过渡金属催化的C–H键直接芳基化反应为主要合成手段，简洁高效地合成一系列具有结构多样化特征的含氮杂环（唑类杂环和嗪类杂环）发光材料，进而开展与之相关的结构-性能关系研究。（1）合成了三种C2(5)-C2ʹ(5ʹ)位点连接的联二噁唑衍生物。综合实验和量化计算数据，C5-C5′_BOxz的分子堆积更紧密，可潜在应用于OFET器件中。而C2-C2′_BOxz在三者中具有最大的光致发光量子产率（PLQY）（0.77）和最大辐射跃迁速率（5.50×10^8 s^-1），表明C2-C2′_BOxz在三者中发光性能最好，有望应用于有机发光材料领域中。（2）在2-（2ʹ-羟基苯基）噁唑核心上酚羟基的对位和噁唑环C5位分别引入供电子特性的三苯胺或吸电子特性的三苯基硼烷用以调节分子醇式和酮式构象比例，从而改变其发射光谱和PLQY。将其中两种分子作为发光材料应用于OLED，器件的外量子产率（EQE）分别达到了4.9%和5.6%。（3）合成了六种基于3,4-乙烯二氧噻吩片段的交替型共轭聚合物，表现出优异的传输电荷和存储电荷性能，有望应用于高性能的柔性有机半导体器件领域。（4）合成了三十余种基于多氮杂环核心（包括酚嗪、三嗪和庚嗪环）的有机发光材料。这些材料在室温下即可表现出明显的长寿命磷光（长达608 ms）或较长寿命的热激活延迟荧光现象，后者作为发光层材料应用于OLED器件，EQE可达到12.5%。