Delocalization of excited states of organic semiconductors is directly related to their efficiency in devices. Time-resolved electron paramagnetic resonance spectroscopy provides unique capabilities in this respect because of its high spectral resolution and capability to probe the geometry and extent of excitons. Using magnetophotoselection experiments, the mode of exciton delocalization, along the backbone or parallel to the π–π stacking direction of the conjugated polymers, can be revealed. We demonstrate the robustness of this approach by applying it to building blocks of a prototypical conjugated polymer showing a symmetry of their excited states being far from ideal for this experiment. This renders magnetophotoselection superior to other approaches because it is applicable to a wealth of other organic semiconductors. The insight gained into exciton delocalization is crucial to the structure–function relationship of organic semiconductors and directly relevant for developing highly efficient materials.

中文翻译：

---

探索有机半导体中的激子离域：时间分辨电子顺磁共振和磁光选择实验的见解

有机半导体的激发态的离域化与它们在装置中的效率直接相关。时间分辨电子顺磁共振光谱在这方面具有独特的功能，因为它具有高光谱分辨率和探测激子的几何形状和范围的能力。使用磁光选择实验，可以揭示出沿骨架或与共轭聚合物的π–π堆积方向平行的激子离域模式。我们通过将其应用于原型共轭聚合物的结构单元来证明这种方法的鲁棒性，该模型显示出其激发态的对称性远非本实验的理想选择。这使得磁光选择优于其他方法，因为它适用于许多其他有机半导体。