Time-resolved EPR for probing ordering in conjugated polymers and primary processes of charge generation in organic electronic devices

有机半导体广泛应用于从发光二极管（oled）和晶体管（ofet）到太阳能电池（OSCs）的各种应用中。与传统无机半导体相比，它们的优势在于成本低，而且在定制所使用的分子时几乎具有无限的灵活性。电荷的产生、分离和传输是开发高效有机电子学需要进一步研究的关键方面。聚合物的形态是影响有机电子器件效率的最关键因素之一，因为它们之间存在着强烈的结构-功能关系。电子顺磁共振（EPR）光谱学几乎非常适合研究用于有机电子学的共轭聚合物，因为大多数光诱导态是顺磁性的，因此可以被检测到。本项目的重点是通过时间分辨EPR光谱研究共轭聚合物和有机电子器件中光诱导初级过程的形态和顺序。微观过程与聚合物的形态和宏观器件效率相关。由于结构-功能关系强，因此控制样品的形貌至关重要。只有在与有机电子器件相比较的情况下，光谱结果才能与器件特性相关联。在一个系统的方法中，用于有机电子的材料将被光谱研究-从构建块开始，通过低聚物和聚合物继续到实际设备中使用的供体和受体材料的混合物。为了将形态学、微观过程和宏观器件效率联系起来，将建立一个EPR装置来研究整个有机电子器件（ofet, OSCs）。通过开发涵盖不同场景的易于使用的模拟程序框架，将促进自旋极化EPR光谱的分析。

Organic semiconductors are used in a large number of applications ranging from light-emitting diodes (OLEDs) and transistors (OFETs) to solar cells (OSCs). Their advantage over conventional inorganic semiconductors is the low-cost and nearly endless flexibility in tailoring the molecules used. Generation, separation, and transport of charges are crucial aspects that need further investigation to develop efficient organic electronics. Morphology of the involved polymers is one of the most crucial aspects for the efficiency of organic electronic devices due to the existing strong structure-function relationship. Electron paramagnetic resonance (EPR) spectroscopy is nearly ideally suited to investigate conjugated polymers used for organic electronics, as most of the light-induced states are paramagnetic and can therefore be detected.The focus of this project is on investigating morphology and ordering in conjugated polymers and light-induced primary processes in organic electronic devices by time-resolved EPR spectroscopy. The microscopic processes are correlated with both, the morphology of the polymers and the macroscopic device efficiency. Due to the strong structure-function relationship, it is crucially important to control the sample morphology. Only if it is comparable to that in organic electronic devices, spectroscopic results can be correlated to device characteristics.In a systematic approach, the materials used for organic electronics will be investigated spectroscopically - starting out with the building blocks and continuing via oligo- and polymers to the blends of donor and acceptors materials used in the actual devices. To correlate morphology, microscopic processes and macroscopic device efficiency, an EPR setup to investigate whole organic electronic devices (OFETs, OSCs) will be built. Analysis of spin-polarised EPR spectra will be facilitated by developing an easy-to-use framework of simulation programs covering the different scenarios.