2025-06-08
Molecules, Vol. 30, Pages 2513: Tuning the Inter-Chromophore Electronic Coupling in Perylene Diimide Dimers with Rigid Covalent Linkers
Guo Yu, Yixuan Gao, Yonghang Li, Yiran Tian, Xiaoyu Zhang, Yandong Han, Jinsheng Song, Wensheng Yang, Xiaonan Ma
The organic multi-chromophore system has been increasingly attractive due to the potential optoelectronic applications. The inter-chromophore electronic coupling (EC), i.e., JCoul and JCT, plays a critical role in determining the relaxation path of the excited state. However, the molecular designing strategy for effective tuning of inter-chromophore EC is still challenging. In this computational work, we designed a series of perylene diimides (PDI) covalent dimers with rigid linking cores containing thiophene (Th) or phenyl (Ph) fragments and performed corresponding theoretical investigation to analyze the inter-PDI electronic coupling. Vibrational analysis indicated that the minimized excited state structural relaxation (ES-SR) can ensure the rigid inter-PDI geometry pre-defined by the topological characteristic of linking cores, leading to comparable |JCoul| on S0 and S1 states. The saddle-shaped linking cores allow collaborative tuning of inter-PDI dihedral (a) and slipping (q) angles, leading to effective tuning of inter-PDI |JCoul| = 0–1000 cm−1. Our work provides a new molecular designing strategy for effective tuning of inter-chromophore EC for organic chromophores. By using a rigid inter-chromophore structure, the ignorable ES-SR allows simplified molecular designing without considering the plausible geometric difference between S1 and S0 states, which might be useful for future applications in organic optoelectronics.