主体型蓝色磷光材料及新型全磷光白光器件的设计及性能研究

For current white organic light-emitting diodes (WOLEDs) based on the phosphorescent emitters, the inherent difference between the organic fluorescent host molecules and the phosphorescent dopant emitters in their optoelectric properties: energy gaps (Eg) between the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) levels, life time of excited state, etc., inevitably cause the unfavorable energy losses in the processes of both the created singlet and triplet excitons on the fluorescent host and their transferring to triplets of the phosphorescent dopant, usually leading to the relatively low EL efficiency and/or the significant efficiency roll-off at high luminance. To solve these problems above, in this project, our research mainly focuses on design of new host-type blue phosphorescent materials with the desirable bipolar charge-transporting ability, which could be used as the host emitting materials in the novel all-phosphor white OLEDs, where the blue phosphors are employed as both the blue emitters and the hosts for sensitizing other phosphorescent emittters, The innovations of this project are showed as below: design and obtain bipolar blue phosphors through introducing our original ancillary ligands as well as building all-new-structure complexes, and realize novel and simple all-phosphor type (phosphor host-phosphor guest) WOLEDs based on these new bipolar phosphors acting as the blue emitters and the hosts, where any additional fluorescent host and/or emitting molecules are no longer needed and the higher performance white electroluminescence should be achieved. We will get some key techniques with independent intellectual property rights, apply for 1-2 invention patents, and publish over 10 high-level scientific papers with the Impact Factor (IF) 3.0, when this project is finished successfully.

在目前基于磷光材料制备的白光器件中，荧光主体与磷光客体间各种固有物性，如光学能隙和激发态寿命等性能上存在的较大差异，导致在产生激子及能量转移过程中均伴随着不可避免的能量损失，从而造成器件效率不高或明显的效率滚降。为了解决上述问题，本项目致力于设计并获得具有双极传输特性的新型蓝色磷光分子，并将其作为蓝色发光材料及主体材料用于一种新型的、基于磷光主体-磷光客体掺杂发光体系的全磷光型白光器件的制备。本项目的特色及创新之处在于，通过引入原创的辅助配体构筑全新配合物构型来获得全新的、具有双极传输特性的蓝色磷光分子，并作为新型主体材料来主导结构新颖、简单的全磷光型白光器件的制备，避免了传统的荧光分子作为蓝色发光或主体材料的引入，从而获得更高性能、更高品质的白光发射。通过项目的完整实施，将形成一些具有自主知识产权的关键技术，申请发明专利1-2项，并发表10篇以上的高水平（IF大于3.0）SCI研究论文。

为了解决目前白光器件中，由于主体与客体间各种固有物性上存在的较大差异，导致在产生激子及能量转移过程中不可避免的能量损失，本项目设计并获得了不同类型的、具有双极传输特性的新型主体型蓝光分子，并将其用于非掺杂蓝光器件，以及不同主体-客体掺杂发光体系的单色及白光器件的制备。探索、优化并实现了不同器件结构、不同发光机制、不同品质、高性能的电致发光过程。目前，我们已经获得了一系列发光颜色覆盖广、发光效率高、具有双极性载流子传输特性的主体型发光分子，并成功制备了具有结构简单、低压驱动、高亮度、高效率以及低的效率滚降等特点的蓝、绿、黄、橙、红及白光器件。这充分说明主体型发光材料综合性能的提升，是实现更为简单、高效EL发射最有效的途径之一，这是让有机电致发光技术更快、更全面走向实用化所做的必要的基础研究。本项目的研究从一定程度上解决了有机电致发光材料和器件领域共同面对的科学问题，这也是本项目创新性的重要体现。