基于激发态分子内质子转移化合物的非能量传递型二元互补色固态白光OLED材料体系的设计与性质研究

Conventional complementary-color white-emitting systems are based on incomplete energy transfer mechanism. Due to difficult control of the extent of energy transfer, single-emitting layer WOLEDs utilizing these systems have problems of color instability, difficult control and poor repetition. In our work, a new strategy of designing non-energy-transferred complementary-color systems has been proposed, by utilizing solid-state emissive excited state intramolecular proton transfer (ESIPT) fluorophores as the low-energy emitting components. Due to the unique four-level photocycle in the ESIPT compound, there is almost no population of the ground state of its keto tautomer (acceptor) which is energetically matched with the excited state of the high-energy components (donor). Thus, the energy transfer from the excited state of the high-energy blue-emitting component to the ground state of the low-energy ESIPT yellow/orange-emitting one can almost be completely blocked. By doping with appropriate TADF sensitizers, the WOLEDs efficiencies can be improved. On this basis, the factors which affect the solid state emission and WOLED performances were thoroughly investigated, further providing guides to improvement of molecular design for obtaining high device efficiencies. Therefore, new stable and controllable solid-state emissive frustrated-energy-transfer complementary-color emitter systems can be anticipated, which provides some theoretical and experimental illuminations in fields of WOLED materials.

传统的单发光层二元互补色白光体系是通过分子内的不完全能量传递来实现白光发射的，但由于能量传递程度难以精确控制，存在色坐标不稳定、不易控制、重复性差等缺点。本课题拟选择固态发光的激发态分子内质子转移(ESIPT)黄/橙光衍生物作为低能发光单元，利用其特殊的四能级跃迁光物理过程使得受体中能级匹配的酮式基态的布居数几乎为零，从而阻断了从高能蓝光组分激发态到低能黄/橙光组分基态的能量传递，由此设计可控的非能量传递型二元互补色白光材料体系。选取合适的延迟荧光材料进行掺杂敏化，提高WOLED器件效率。在此基础上，通过研究材料固态发光行为以及器件性能的影响因素，帮助指导改进分子设计，进一步提高器件性能，最终得到新型、稳定、可控的非能量传递型二元互补色固态白光OLED 材料体系，为WOLED 材料研究领域提供一定的理论和实验依据。

设计了系列高性能的固态发光有机光电材料，并研究其内在固态发光机制。在此基础上，设计了一系列非能量传递型的具有延迟荧光性质的激发态分子内质子转移白光OLED材料，并详尽研究其光物理机制；通过器件优化获得制备工艺简单、色坐标重复性高的高效白光OLED器件，为后续设计新型白光OLED材料提供理论和实验依据。另外，通过引入特殊的光物理光化学性质，设计系列具有优异性能的温度传感、压力传感、离子传感、电存储及生物标记材料，为后期进一步实现多功能有机光电器件提供了前期基础。