Donor-acceptor single cocrystal of coronene and perylene diimide: molecular self-assembly and charge-transfer photoluminescence

Abstract

The research on donor-acceptor (D-A) cocrystalline structures based on organic semiconductive molecules has drawn great attention due to their unique optical and electronic properties. Among the building block molecules, derivatives of perylene-3,4,9,10-tetracarboxylic-3,4,9,10-diimides (PTCDI) are of particular interest as these molecules form high performance n-type semiconductors with strong air stability. However, the cocrystal of PTCDIs remains challenging to fabricate, and only few D-A cocrystals of PTCDIs have been reported. Herein, we report a successful molecular self-assembly design for the PTCDI cocrystal with a donor molecule, coronene. Within the triclinic cell of the cocrystal, the PTCDI and coronene molecules achieved 1 : 1 alternated π-π stacking. The cocrystal showed clear red-shifted absorption and photoluminescence bands, implying the strong charge transfer interaction between coronene and PTCDI. Additionally, the cofacial π-π stacking between coronene and PTCDI planes favors strong one-dimensional self-assembly, leading to the formation of microsized fibril cocrystals and arrays. This presented cocrystal design strategy helps to explore new D-A cocrystalline structures, particularly with one-dimensional morphology control.