Controlling of the interplay between order and disorder by side-chain based statistic block-copolymers for photovoltaics

本项目的目标是获得对低带隙聚（对亚芳基-乙炔基）-交替-聚（对亚芳基-乙烯基）共聚物的π−π堆积能力的合成控制。这通过接枝直链和/或支链烷氧基侧链来实现。特别强调的是侧链为基础的统计嵌段共聚物组成的线性以及分支的侧链随机分布在共轭主链的序列。目的是建立聚合物的π-π堆叠能力、聚合物和聚合物-富勒烯光活性层的电子和物理性质、后者的纳米级形态与太阳能电池的光伏性能之间的相关性。活性层中的纳米级相分离也将通过使用用于膜制备的溶剂的混合物以及通过改变不同富勒烯衍生物的溶解度来调节。将通过原子力显微镜、散射方法和光学显微镜在宽的长度尺度范围内研究形态。我们将实施新的空间和时间分辨的散射方法，允许监测形态变化，如自组装和相分离过程中的真实的打印和退火过程在线。为了获得有关材料长期稳定性的知识，我们将进行光降解研究和太阳能电池寿命调查。

The goal of the present project is to gain synthetic control over the π−π stacking ability of low band gap poly(p-arylene-ethynylene)-alt-poly(p-arylene-vinylene)s based copolymers. This is attained through grafting of linear and/or branched alkoxy side chains. Special emphasis will be laid on side chain based statistic block-copolymers consisting of sequences of linear as well as branched side chains randomly distributed within the conjugated backbone. The aim is to establish a correlation between the π−π-stacking ability of the polymers, the electronic and photophysical properties of the polymers and polymer-fullerene photo-active layers, the nanoscale morphology of the latter up to the photovoltaic performance of the solar cells. The nano-scale phase separation in the active layers will also be tuned by using mixture of sol-vents for film preparation as well as by changing the solubility of different fullerene derivatives. The morphology will be investigated over a broad length scale range by atomic force microscopy, scattering methods and optical microscopy. We will implement new spatially- and time-resolved scattering methods which allow monitoring morphological changes such as self-assembly and phase separation during real printing and annealing processes online. In order to gain knowledge about the long-term stability of the materials we will perform photo-degradation studies and solar cell lifetime investigations.