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，报道了从卤化溶剂到约100 nm厚的有源层的旋涂光活性层的最高效率。结果表明，这类薄膜具有良好的分子间纳米结构和低能无序。当从非氯化溶剂打印更厚的活性层时，这种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设备和旋涂最先进的太阳能电池的性能之间的详细分析，将能量无序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计具有不同的混相性、界面相互作用和形态，从而具有能量无序。为此，在本项目中，我们将使用瞬时吸收、延迟采集场和光电流-光致吸收来研究自由电荷的产生和复合随场和温度的变化。另一方面，空间限制电荷电流测量将用于量化打印设备的能量无序和迁移率。结果将与该联盟的小组一起进入详细的设备模拟。我们的研究将从旋涂设备上已经报道的高效率的选定材料组合开始，并继续在本研究单位的过程中开发单组分有源层，这也将从第二个资助期的重点开始。

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.