Tuning of polymer aggregation and optimization of the active layer morphology of all-polymer solar cells incorporating rylene-based acceptor polymers

所提出的工作旨在通过优化电子接受相的电子传输特性来理解和推进聚合物基有机太阳能电池的光伏特性。本论文将合成一种新型的基于萘二酰亚胺的低带隙电子接受共聚物，该共聚物具有较好的电子迁移率。这些共聚物的HOMO和LUMO能级被设计用于与公认的给电子聚合物如聚（3-己基噻吩）（P3 HT）组合。纯聚合物和共混物中的电子传输将被研究，并与光伏器件的性能。为了优化这些本体异质结器件的光学和电子传输特性，将研究包括给电子聚合物、电子接受聚合物和众所周知的可溶性富勒烯PCBM的三元共混物的形态、电荷传输和太阳能电池特性。因此，通过化学设计调整受体聚合物的LUMO能级与PCBM的能量结构将是本项目的重要任务之一。通过使用具有低带隙的受体聚合物，设想了宽的光谱覆盖。最后，作为嵌段共聚物或低分子量软化剂（和表面活性剂）的添加剂对聚合物-聚合物共混物的形态的影响将进行研究，其目标是开发新的方法对聚合物共混物具有高电荷载流子解离和提取效率。

The proposed work aims at the understanding and the advancement of the photovoltaic properties of polymer-based organic solar cells by optimizing the electron-transport properties of the electron-accepting phase. Novel “low bandgap” electron-accepting copolymers based on naphthalenebisimide with improved electron mobility will be synthesized. The HOMO and LUMO energy levels of these copolymers are designed for a combination with well-established electron-donating polymers such as poly(3-hexylthiophene) (P3HT). Electron-transport in the pure polymer and in the blend will be studied and related to the photovoltaic device performance. In order to optimize the optical and electron-transporting properties of these bulk-heterojunction devices, ternary blends comprising an electron-donating polymer, an electron accepting polymer and the well-known soluble fullerene PCBM will be investigated with respect to morphology, charge transport and solar cell properties. Hereby, the adjustment of the LUMO level of the acceptor-polymer with respect to the energetical structure of PCBM by chemical design will be one important task of this project. By using acceptor polymers with low bandgap, wide spectral coverage is envisaged. Finally, the influence of additives as block copolymers or low molecular weight softeners (and surfactants) on the morphology of polymer-polymer blends will be investigated, with the goal to develop novel approaches towards polymer blends with high charge carrier dissociation and extraction efficiencies.