Multiblock co-oligomers with predefined and monodisperse segments and thermodynamicallystable lamellar morphology for non-fullerene solar cells

POPULAR研究单位的项目1的目标是控制和预测非富勒烯（NFA）太阳能电池的形态，并提高其形态的长期稳定性。使用单分散嵌段的供体-受体多嵌段共低聚物，我们将通过自组装产生热稳定的层状形态。片层的宽度和长周期将预测和决定的供体和受体段的长度。在化学上，低聚供体片段将基于现有技术材料PM 6的重复单元，而受体片段将基于已建立的PNDIT 2。作为一个关键特征，将制备具有明确端基的单分散低聚物并将其并入多嵌段共低聚物中。与共轭供体-受体嵌段共聚物的文献报道不同，嵌段的单分散性将允许非常明确的界面。此外，可以完全消除与再现性和批次间差异相关的问题。此外，在供体和受体区段之间使用非缀合的接头将为两个区段的增强分离提供空间，并且另外防止电荷重组。在第二个四年期间，这种方法将扩展到更多的非富勒烯受体，其中PNDIT 2被更高性能的受体（如Y 6）取代。迄今为止未知的多嵌段共聚低聚物将由POPULAR财团使用分子，光电，热，结构和设备相关的方法进行全面研究，并最终阐明其适用于印刷太阳能电池。

The goal of Project 1 within the Research Unit POPULAR is to control and predict morphology of non-fullerene (NFA) solar cells and increase their morphological long-term stability. Using donor--acceptor multiblock co-oligomers with monodisperse blocks, we will generate thermodynamically stable, lamellar morphologies by virtue of self-assembly. Lamellar widths and long periods will be predicted and determined by the length of the donor and acceptor segments. Chemically, the oligomeric donor segments will be based on the repeat units of the state-of-the-art material PM6, while the acceptor segment will be based on established PNDIT2. As a key feature, monodisperse oligomers with well-defined end groups will be prepared and incorporated into multiblock co-oligomers. Unlike literature reports on conjugated donor--acceptor block copolymers, the monodisperse nature of the blocks will allow for extremely well-defined interfaces. Moreover, issues related to reproducibility and batch-to-batch variations can be entirely eliminated. Furthermore, usage of non-conjugated linkers between donor and acceptor segments will give room to enhanced segregation of the two segments and additionally prevent charge recombination. In the second four-year period, this approach will be extended to further non-fullerene acceptors with PNDIT2 being substituted by yet higher performing acceptors such as Y6. The hitherto unknown multiblock co-oligomers will be investigated comprehensively by the POPULAR consortium using molecular, opto-electronic, thermal, structural and device-related methods, and their suitability for printed solar cells will finally be elucidated.