基于苝二酰亚胺的太阳能电池聚合物受体材料的设计合成

Polymer solar cells (PSC) utilizing non-fullerene acceptors are attracting increasing attention and studies. Compared to fullerene derivatives, non-fullerene acceptors boast the advantages of strong light-absorbing abilities, tunable absorption spectra and molecular orbital energy, and more stable donor-acceptor phase separation morphology. While small-molecule acceptors of diverse structures have been extensively developed and studied, polymer acceptors which potentially provide more durable devices and are more suitable for large-area printing techniques have been much less explored, with the investigated structures mainly limited to copolymers of naphthalenediimide and thiophene/selenophene. Compared to NDI, perylenediimide has a larger polycyclic skeleton with stronger pi-pi stacking interactions, is more susceptible to chemical modifications and thus features quite adjustable electronic as well as optical properties. For the these reasons, the current project aims to design and synthesize a number of conjugated polymers incorporating PDI, or polycyclic aromatic diimides derived from it, as the main building block. By using various comonomer units, the backbone structure of the polymers can be greatly diversified. We will investigate the performance of these polymers when applied as the acceptor in PSC. By screening and optimizing the structures of the acceptor polymers, we expect to improve the energy conversion efficiency of the solar cells. Besides the backbone structures, many other factors such as the molecular weight, side chains, and the regularity of the backbone, which can sensitively influence the polymer solubility, crystallizing ability and the donor-acceptor phase separation morphology, will also be systematically examined and optimized.

基于非富勒烯受体的聚合物太阳能电池受到越来越广泛的认可。对比富勒烯分子，非富勒烯受体具有吸光能力强，光谱和能级可调，相分离结构稳定等优点。相对于种类繁多的小分子受体，相分离结构更稳定、更加适合大面积印刷打印技术的聚合物受体结构却相对单调，主要集中于萘二酰亚胺(NDI)与噻/硒吩聚合物的研究。苝二酰亚胺(PDI) 比NDI具有更大的稠环骨架、更强芳香堆积能力，更加灵活的化学修饰性，光谱和能级也因此宽泛可调。鉴于这些优势，本项目计划以PDI及其衍生的稠环芳香酰亚胺作为关键基元，结合不同共聚单体，设计合成多种不同结构的共轭聚合物，考察它们作为太阳能电池受体的性质。通过系统的聚合物结构的筛选和优化，结合最佳器件加工条件的摸索，实现高光电转化效率。除主链结构外，聚合物分子量、侧链结构、主链规整性等多种能够影响聚合物的溶解度、结晶性和给受体相分离形貌的结构因素都是本项目将要系统考察和研究的内容。

基于非富勒烯受体的聚合物光伏器件已成为第三代新型太阳能电池的重要发展方向。对比富勒烯分子，非富勒烯受体具有吸光能力强，光谱和能级可调，稳定性高等优点。相对于种类繁多、性能优越的小分子受体，活性层形貌更加稳定、更加适合大面积印刷打印技术的全聚合物器件的发展瓶颈主要集中于受体聚合物的材料性能有待进一步改善。解决这一问题的重要途径应为拓展材料的结构多样性，开展深入系统的构效关系和结构优化研究。以稠环芳香酰亚胺为主要功能基团的共轭聚合物是聚合物受体材料的重要类型，具有良好的发展前景。其中，苝二酰亚胺(PDI)具有较大的稠环骨架、更强芳香堆积能力，更加灵活的化学修饰性，光谱和能级也因此宽泛可调。鉴于这些优势，本项目以PDI作为关键基元，结合不同共聚单体，设计合成多种结构的共轭聚合物，研究它们作为全聚合物光伏器件受体材料的性质。通过系统的聚合物结构筛选和优化，结合最佳器件加工条件的摸索，本项目获得重要研究进展。首先，发展出了基于PDI的高性能聚合物受体材料，显著提高了全聚合物器件的光电转化效率。除了PDI作为基本结构之外，我们还基于PDI设计开发了全新的衍生化的稠环芳香酰亚胺，并将这些新结构分子作为主要结构基元，分别制备合成了多种聚合物受体材料，运用于全聚合物太阳能电池中进行了表征。通过合理的分子设计和器件加工条件优化，这些新材料分别实现了高开路电压、高载流子迁移率等不同的特点和优势，为新聚合物受体材料和高性能全聚合物太阳能电池开发奠定重要实验基础。