Controlling Molecule Aggregation and Electronic Spatial Coherence in the H-Aggregate and J-Aggregate Regime at Room Temperature

Controlling molecule aggregation in polymer films is one of the key factors in understanding the links between properties and structures in organic semiconductors. Here, we used poly(3-hexylthiophene-2,5-diyl) (P3HT) as the model system. By doping the insulating polar additive poly (ethylene oxide) (PEO) into P3HT film and controlling the processing methods, we achieved the side-to-side H-aggregate and head-to-tail J-aggregate of P3HT molecules with different extents at room temperature. We have demonstrated that the solvent solidification rate plays an important role in the controlling of molecule aggregation, which finally influenced the solid-state phase separation in the film. Furthermore, based on a series of spectroscopy investigations, we quantified the electronic spatial coherence in different aggregations combined with the modified Franck-Condon model. Subsequently, we established the relationship between the processing method, the molecule aggregation, and the electronic spatial coherence.