Optoelectronic characterization of printed organic solar cells

对于非富勒烯受体（NFA）为基础的有机太阳能电池，最高效率的报道与旋涂的光活性层，从卤化溶剂与约。100 nm厚的有源层。这些层显示出良好定义的分子间纳米结构和低能量无序。当用非氯化溶剂印刷较厚的活性层时，情况可能会发生很大变化。在这项提案中，我们将通过提供由良性溶剂形成的印刷器件的特性与旋涂最先进的太阳能电池的特性之间的详细分析，将能量紊乱与光伏参数联系起来。由非卤化溶剂印刷的较厚的活性层预期具有不同的可溶解性、界面相互作用和形态，从而具有能量无序。为此，在该项目中，我们将采用瞬态吸收，时间延迟收集场和光电流光致吸收研究，自由电荷的产生和复合作为场和温度的函数。另一方面，空间限制的电荷电流测量将用于量化印刷设备的能量紊乱和迁移率。结果将与财团的小组一起进入详细的设备模拟。我们的调查将从选定的材料组合开始，这些材料组合在旋涂设备上已经报告了高效率，并继续在本研究单元的过程中开发单组分有源层，这也将是第二个资助期的重点。

For non-fullerene acceptor (NFA)-based organic solar cells, highest efficiencies are reported with spin-coated photoactive layers, from halogenated solvent with ca. 100 nm thick active layers. Such layers were shown to exhibit a well-defined intermolecular nanostructure and low energetic disorder. The situation may largely change when printing thicker active layers from non-chlorinated solvents. In this proposal, we will link energetic disorder to the photovoltaic parameters by providing detailed analysis between properties of printed devices formed from benign solvents and those of spin-coated state-of-the-art solar cells. Thicker active layers printed from non-halogenated solvents are anticipated to have different miscibility, interfacial interaction and morphology thereby energetic disorder. To this end in the project we will employ transient absorption, time-delayed collection field and photocurrent-photoinduced absorption to study, free charge generation and recombination as a function of field and temperature. On the other hand, space limited charge current measurements will be used to quantify energetic disorder and mobility of printed devices. The results will enter detailed device simulation together with groups of the consortium. Our investigations will start with selected material combinations for which high efficiencies are already reported on spin-coated devices and continue with single component active layers to be developed in course of this Research Unit, which will also from the focus of the second funding period.