具有高激子利用效率的给/受体型蓝光聚合物的设计合成

The hybridized local and charge-transfer (HLCT) excited state not only retains the CT state character as weakly bound exciton, but also possesses a very large wavefunction overlap to maintain a certain rate of radioactive transition. Accordingly, it will be expected to devolop the next generation organic light-emitting diode (OLED) materials with low-cost and high performances. Donor-acceptor(D-A) type building blocks are commonly used as the synthsis of narrow band gap electron-donor materials for polymer solar cells, and therefore, it is a great challenge to design the blue light-emitting polymers used D-A type unit. Also, it can open a new direction to improve the efficiency and stability of light-emitting polymers. Dibenzothiophene-S,S-dioxide (SO) is an excellent blue emitters with high performances due to its high fluorescence quantum yields and excellent chemical and thermal stability, which can be constructed D-A type building block as promising blue emitter. And the blue light emitting polymers with the high device efficiency and stability will be obtained by intruducing D-A type building block into the wide band gap polymer backbone. Based on the theory of HLCT excited state, this project will design and synthesize a series of blue light-emitting polymers containing the SO based D-A type blue emitters. And the theoretical model calculation, polymer molecular design and the luminescence mechanism of HLCT excited state will be carried out, in order to exploit D-A type blue emitting polymers with high exciton ultilization efficiency, and further explore a new way on the the practical application of blue light-emitting polymers.

突破激子统计限制的局域/电荷转移杂化（HLCT）态新原理，既保留了CT态激子弱束缚特性，同时又具有较大的波函数重叠和高辐射跃迁速率，据此有望发展低成本、高性能的新一代有机电致发光材料。給/受体型结构单元多用来合成聚合物太阳电池的窄带隙给体材料，将其用于蓝光聚合物分子设计是一个全新的挑战，也为聚合物荧光材料器件效率及稳定性的提高提供了一种新思路。S,S-二氧-二苯并噻吩是一个发光效率高、稳定性好的蓝光单元，以其为基础构筑的新型给/受体型蓝光单元，在性能上将有很大的提升空间；将其引入宽带隙聚合物分子链中，有可能获得高激子利用效率的的蓝光聚合物。本项目基于HLCT态新原理，设计若干基于S,S-二氧-二苯并噻吩的给/受体型蓝光单元。通过模型化合物理论计算、聚合物分子设计、HLCT态发光机制及其相互影响的研究,指导合成具有高激子利用效率的给/受体型蓝光聚合物，探讨解决蓝光聚合物实用化问题的新途径。

有机发光平板显示（OLED）已开始大规模应用。高分子发光显示(PLED) 可通过喷墨打印等溶液加工的方式实现大面积制备，有助于进一步降低制造成本，实现商业化生产。当前制约高分子平板显示产业发展的关键因素是蓝光聚合物发光效率低、光谱稳定性差。本项目设计若干基于S,S-二氧-二苯并噻吩衍生物的新型给/受体蓝光单元，通过模型化合物理论计算、聚合物分子设计, 指导合成新型含给/受体发光单元的高效、稳定的蓝光聚合物，探索解决蓝光聚合物实用化问题的新途径。1）在聚(芴-co-S,S-二氧-二苯并噻吩)的侧链引入咔唑、主链末端引入三芳胺单元, 空穴传输单元修饰聚（芴-co-S,S-二氧-二苯并噻吩）衍生物PFCz25SO器件的流明效率: 5.52 cd/A，色坐标(0.17，0.17)。2）将砜基S,S-二氧-螺[芴-9,9-噻吨]单元（FSO和SOF）分别引入到聚芴主、侧链, 蓝光PPF-SOF15器件的流明效率: 2.0 cd/A、外量子效率: 3.76%，色坐标(0.16, 0.08)。PF-27SO20深蓝光器件的流明效率: 2.30 cd/A、外量子效率: 4.05%，色坐标(0.16，0.08)。3）将五元稠环单元BTOF和BTOCz分别引入聚芴、聚咔唑主链，含BTOF单元聚芴，PF-BTOF30器件的流明效率: 3.70 cd/A、外量子效率: 3.50 %、色坐标 (0.16, 0.17)。含BTOF单元聚咔唑，PCz-BTOF20器件的流明效率: 3.10 cd/A、外量子效率: 2.55 %、色坐标(0.16, 0.21)。在初始亮度为500 cd/m2，PF-BTOF30和PCz-BTOF20的亮度半衰期分别为为3、4小时，而其均聚物PF和PCz的寿命小于5分钟。含BTOCz单元聚芴，PF-BTOCz30器件的流明效率: 6.26 cd/A、外量子效率: 4.95 %、色坐标(0.16, 0.21)。含BTOCz单元聚咔唑，PCz-BTOCz20器件的流明效率: 3.91 cd/A，色坐标(0.17, 0.25)。聚合物PF-BTOCz30和PCz-BTOCz20器件在高电流密度下(~500 mA/cm2)，发光效率滚降小、器件稳定性好，具有潜在的应用前景。.已发表SCI论文 13篇、申请中国发明专利 4项。培养了1名硕士、4名博士、 1名博士生在读。