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poly(p-arylene-ethynylene)-alt-poly(p-arylene-vinylene)s共聚物的π−π堆积能力的综合控制。这是通过接枝直链和/或支链烷氧基侧链来实现的。将特别强调基于侧链的统计嵌段共聚物，该嵌段共聚物由随机分布在共轭主链内的线形和支化侧链序列组成。其目的是建立聚合物的π−π堆积能力、聚合物的电子和光物理性质与聚合物-富勒烯光活性层之间的关联，后者的纳米级形貌与太阳能电池的光伏性能之间的关系。通过使用混合溶剂制备薄膜以及改变不同富勒烯衍生物的溶解度，也可以调节有源层中的纳米级相分离。我们将用原子力显微镜、散射方法和光学显微镜在很大的长度范围内研究其形貌。我们将实施新的空间和时间分辨散射方法，允许在线监测真实打印和退火过程中的形态变化，如自组装和相分离。为了了解材料的长期稳定性，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.