基于聚集诱导发光分子和吡咯并吡咯二酮的新型三维结构非富勒烯小分子受体材料及其柔性有机光伏器件

Due to the drawbacks of the conventional fullerene acceptors such as weak absorption of visible light, limited energy level variability, easy aggregation to large domains and high cost, it’s urgent to develop novel non-fullerene acceptors for bulk-heterojunction (BHJ) organic solar cells (OSCs). In this project, a series of novel 3D AIE-DPP non-fullerene acceptors based on aggregation-induced emission (AIE) molecular core and diketopyrrolopyrrole (DPP) arm are designed and synthesized by simple reactions. The universal AIE-DPP acceptors with 3D molecular structure, similar to the fullerene, could not only possess a 3D charge-transporting network for efficient charge separation and transportation, but also form a desirable morphology of the active layer with donors. At the same time, AIE-DPP acceptors have stronger absorption of visible light and controllable energy level, and the 3D molecular structure can avoid aggregation to large domains. In addition, the variously spatial configuration of the AIE-DPP acceptors is beneficial to investigate and reveal the intrinsic mechanism of the chemical structure and molecular geometry of non-fullerene acceptor on the device performance. And the characteristic of the AIE is anticipated to introduce special charge transfer path and photovoltaic property on the novel acceptors. Systematically study the correlation of the structure with light absorption, energy level, microstructure and charge transfer. Subsequentlly, fabricate highly efficient OSCs and flexible devices.

有机太阳能电池中的富勒烯受体存在光吸收差、能级调控难、易聚集和价格昂贵等缺点，因此发展高性能新型非富勒烯受体显得尤为迫切。本项目提出以三维结构聚集诱导发光（AIE）分子为核，高迁移率吡咯并吡咯二酮（DPP）为臂，通过简单易行的反应，构筑新型高性能AIE-DPP三维结构非富勒烯小分子受体材料。新型受体的独特优势是：其三维结构具有类似富勒烯的三维电荷高效分离和传输，易于与给体形成理想的活性层形貌，具有普适性；同时，其又可以弥补富勒烯的不足，易于化学修饰和能级调控，光吸收能力好，三维结构可以防止其大规模聚集；另外，空间立构各异的AIE-DPP三维结构有利于比较和揭示分子化学结构和空间立构对光伏性能的调控机理和本质规律，AIE特性又有望赋予新型受体一些特殊的电荷转移形式及光电性能。深入研究受体分子结构对光吸收、能级结构、微相结构及电荷分离和传输效率的调控机制，组装高性能太阳能电池及其柔性器件。

本项目主要发展了一系列新型以聚集诱导发光（AIE）分子为核，高迁移率吡咯并吡咯二酮、苝酰亚胺、咔唑等结构单元为臂的高性能三维结构受体分子。利用新型AIE分子特有的聚集诱导发光性能产生的光转换效应来提升活性层对光的高效利用，利用三维结构来填充晶界提高活性层形貌，提高器件的光伏性能。深入研究受体分子结构对光吸收、能级结构、微相结构及电荷分离和传输效率的调控机制，建立AIE在光伏器件中结构与性能之间的关系，组装了高性能光伏电池器件，开拓了AIE分子在光伏领域中的应用。另外，本项目还进一步探索了非富勒烯太阳能电池的非卤溶剂加工工艺和大面积加工工艺，为未来电池的商业化提供一定基础。