Directional crystallization of semiconducting homopolymers and novel donor-acceptor diblock copolymers for control of nanostructure and optoelectronic properties

供体-受体嵌段共聚物是一种极具潜力的有机太阳能电池材料。通过自组装，它们能够形成热力学稳定的供体-受体纳米结构。这种纳米结构是光诱导电荷有效分离成空穴和电子的基本要求。与通常使用的供体/受体共混物相比，嵌段共聚物可以更好地控制形态，避免形态降解。虽然对供体-受体嵌段共聚物复杂的自组装行为已经有了基本的了解，但目前的研究仅限于少量的模型材料，并且尚未实现微相结构的必要对齐。这个提议解决了这两个问题。新的优化材料将被合成，并使用这些材料，我们计划探索界面诱导，定向结晶作为一种手段来创建良好排列的供体-受体纳米结构，以确保有效的电荷传输。为了解决这两个相互交织的目标，该项目由两个具有适当专业知识的小组之间的合作组成。在项目的高分子化学部分，将分别合成带有P3HT供体嵌段的侧链功能化嵌段共聚物和全共轭嵌段共聚物，以及基于低Tg和聚二酮吡咯的新型优化受体嵌段的PCBM。这些材料的自组装将被预先研究，以确保结构的形成是由结晶驱动的。在聚合物物理部分，第一部分将使用聚合物化学提供的模型材料研究获得完全定向晶体薄膜的先决条件。第二步，将详细阐述的定向结晶和外延定向方法转移到嵌段共聚物上，以获得具有定向供体-受体纳米结构的薄膜。电特性将在二极管设置（SCLC）测量中进行，给出有关垂直电荷传输的信息。

Donor-acceptor block copolymers are potentially promising materials for organic solar cells. By self-assembly they are able to form thermodynamically stable donor-acceptor nanostructures. Such nanostructures are a fundamental requirement for efficient photoinduced charge separation into holes and electrons. Compared to the usually used donor/acceptor blends, block copolymers offer increased control over the morphology and avoid morphological degradation.While basic understanding of the complex self-assembly behavior of donor-acceptor block copolymers has been achieved, current investigations are limited to a small number of model materials and the necessary alignment of the microphase structure has not been realized. This proposal addresses both of these issues. New optimized materials will be synthesized, and using these materials, we plan to explore interface induced, directed crystallization as a means to create well-aligned donor-acceptor nanostructures to ensure efficient charge transport. In order to address both of the interwoven aims, the project consists of a collaboration between two groups with suitable expertize.In the polymer chemistry part of the project, both side-chain functionalized and all-conjugated block copolymers with a P3HT donor block and new optimized acceptor blocks based on PCBM with low Tg and Polydiketopyrrolopyrrole respectively will be synthesized. The self-assembly of these materials in bulk will be studied beforehand to make sure that structure formation is driven by crystallization. In the polymer physics part, the prerequisites for obtaining fully oriented crystalline films will be investigated in a first part using model materials supplied by polymer chemistry. In a second step, the elaborated methods of directional crystallization and epitaxial orientation will be transferred to block copolymers to obtain films with oriented donor-acceptor nanostructure. Electrical characterization will be performed in a diode setup (SCLC) measurements giving information about vertical charge transport.