超分子协同作用调控聚芴材料聚集行为及其光电性能研究

Polyfluorenes was an important luminescent conjugated polymer, which are widely application in polymer light-emitting diodes (PLEDs) and polymer laser. However, complex aggregation structure of polyfluorenes in solution/film states was significantly affected on their opto-electrical property and subsequently dominated corresponding device performance, stability and reproductivity. According to previous works, the interchain supramoelcular interaction of polymer semiconductors play a key role in determining molecular aggregation structure, film morphology and their opto-electrical property. In the project, we proposed a novel strategy to precisely tune the chain aggregate behavior and film morphology of polyfluorene via synergistic supramolecular interaction, and consequently to improve devices performance and stability. Novel supramolecular polyfluorenes are designed and prepared via supramolecular functionalization, which are further systematic studied to uncover their aggregate behavior in solution and solid film states under synergistic supramolecular interaction and further explored relationship between the precursor aggregation structure in solution and film morphology. Meanwhile, we investigated the effect of aggregation structure on the opto-electrical property of polyfluorene in the solution and film states, and further to reveal the original of aggregation-induced green emission at molecular level. Finally, we also plan to establish the new strategy to precisely tune the molecular aggregate behavior in the solution/film states and their opto-eletrical property via synergistic supramolecular interaction, which was not only useful to insight the molecular reaggragement in the film-forming process but also to lay the foundations for improving, tuning the opto-electrical property of polymer semiconductor in the future.

聚芴半导体是一类重要的发光聚合物，被广泛应用于聚合物发光二极管、有机激光等领域，但其光电性能呈现复杂的聚集态结构依赖性，从而影响光电器件的性能和稳定性。前期研究结果表明，聚合物半导体分子链内/间的超分子作用是影响分子聚集、薄膜形貌和光电性能的重要因素；据此申请人提出通过超分子协同作用精确调控聚芴聚集行为、薄膜凝聚态结构和形貌，并进一步提高器件性能。我们拟通用超分子功能化，制备一系列超分子聚芴材料，研究其在超分子协同作用下在溶液/固体薄膜状态下的聚集行为，阐明溶液前驱体聚集形态与薄膜凝聚态结构和形貌的内在联系，探索聚芴光电性能的聚集依赖性，从分子水平揭示聚芴聚集绿光带的起源，建立超分子协同作用调控聚芴半导体在溶液/薄膜聚集结构及其光物理性质的新方法，对理解溶液加工过程中分子链重组行为和演变具有重意义，为进一步通过超分子方法调控、提高和丰富聚合物半导体光电性能奠定基础。

作为一类重要的发光共轭聚合物，聚芴材料由于高荧光发光效率、深蓝光发光和较高载流子迁移率，被广泛应用于聚合物发光二极管、有机激光等领域，但其光电性能呈现复杂的聚集态结构依赖性，从而影响光电器件的性能和稳定性。申请人通过控制链运动和相态转变提材料性能。申请人已发表40余篇SCI论文、IF>5.0的15篇，包括Advanced Materials、ACS Macro Letters、Macromolecules、The Journal of Physical Chemistry Letters、Nano Energy、ACS Applied Materials & Interfaces、Organic Letters、Journal of Materials Chemistry C、Macromolecular Rapid Communications等。在本项目的资助下，申请人紧紧围绕超分子协同作用下聚芴半导体中链行为和凝聚态结构转变共性科学问题开展工作，进行分子设计：1）面向溶液分子链组装，申请人系统揭示了分子链间及其与溶剂间的非共价键弱作用对分子链行为和组装特性的影响，阐明了光电行为具有的特异性溶剂和分子量效应，创造性提出分子链在溶液中聚集形态在聚合物后加工分子链堆积和薄膜形貌的重要作用，构筑白光电致发光器件（CIE:0.33, 0.35）；2）开拓了超分子共轭聚合物的高分子物理研究领域，系统研究主链构象转变的分子作用机制，动态调控分子链构象与结晶转变，实现了新原理的电致发光器件和有机激光器件，在200 oC退火呈现低阈值（3.0 μJ/cm2）受激放大辐射，在国际上开拓了借助构象变化调控二芳基芴类聚合物光电性质的研究领域，提出了分子主链双侧取代是调控构象行为和相态转变的分子结构设计理念；3）针对目前发光共轭聚合物中的凝聚态结构依赖性，申请人明确提出并论证了单分子发光机制是提高材料发光性能抑制聚集的重要策略，实现大面积均匀（30 cm*5 cm, CIE坐标：x+y<0.3，CE=2.56 cd/A）深蓝光发光，创造性提出了分子构象诱导、超分子封装和多维度拓扑结构设计是实现单分子发光的重要策略，为构筑高性能多功能蓝光激光器和发光器件提供全新的设计理念。总之，在本项目资助下，申请人构筑一系高性能、高稳定性的发光材料，将有助于推动塑料光电子的产业化。