Cocrystal charge transfer COR-TCNB and the relevant ultrafast photodynamics

Charge transfer cocrystals, as a promising class of optoelectronic materials, have attracted significant attention due to their strong intermolecular interactions and efficient electronic coupling between donor and acceptor molecules. However, a comprehensive understanding of their electronic structure and charge transfer dynamics remains crucial for optimizing their functional properties. In this study, the highly symmetrical polycyclic aromatic hydrocarbon coronene (COR) is selected as the electron donor, the 1,2,4,5-tetracyanobenzene (TCNB), known for its strong electron-accepting capability, is chosen as the electron acceptor. Using the microspacing in-air sublimation method, a highly oriented COR-TCNB organic charge-transfer cocrystal is successfully fabricated. Theoretical calculations, consistent with the experimental spectroscopic analysis, illuminate the electronic structure and charge transfer characteristics of the COR-TCNB cocrystal, and reveal charge redistribution and electron delocalization. The time-resolved fluorescence spectroscopy and transient transmission based on the femtosecond pump-probe method reveal the ultrafast photodynamics and charge transfer exciton formation. The present results exhibited the strong interaction of charge transfer and the existence of charge transfer excitons. This study provides new insights into structure–property relationships in charge transfer cocrystals, offering valuable guidelines for designing functional optoelectronic materials.